Nonmelanoma Skin Cancer

Extramammary Paget disease (EMPD) is a rare cutaneous malignancy typically seen in apocrine-rich areas, including the axillae and anogenital region. It presents as a slow-growing, erythematous patch or plaque that commonly is misdiagnosed as an infectious or inflammatory condition.^1,2 Primary EMPD occurs as a intraepithelial neoplasm, whereas secondary EMPD occurs due to epidermotropic metastases or direct extension of an underlying adenocarcinoma into the skin.¹ Most commonly, primary EMPD occurs in situ; however, when present, dermal invasion and metastases from the skin are associated with poorer outcomes.³ Given the rarity of metastatic disease, existing literature is limited to case reports and case series.

We present 2 patients with metastatic primary EMPD who had evidence of invasion on initial biopsy and died secondary to metastatic EMPD. We conducted a comprehensive review of the literature for invasive and metastatic EMPD to highlight key clinicopathologic features, treatment considerations, and the potential for rapid disease progression in cases of invasive EMPD.

Case Series

Patient 1—A 68-year-old White man with a history of breast cancer (in remission) presented to our clinic for further management of biopsy-proven scrotal EMPD. Prior to biopsy, he described a 6-month history of worsening scrotal rash treated with topical antifungals, oral antibiotics, and topical steroids due to presumed diagnosis of intertrigo, cellulitis, and dermatitis, respectively. Clinical examination showed indurated, erythematous, ulcerated plaques involving the bilateral groin, genitalia, and perineum (Figure 1). Skin biopsy confirmed a diagnosis of EMPD with both dermal and lymphovascular invasion. An immunohistochemical profile was positive for CK7 and carcinoembryonic antigen (CEA) and negative for CK20 (Figure 2).

At presentation, the patient had palpable lymphadenopathy and scrotal edema concerning for inguinal and iliac lymph node metastases. Workup for an underlying adenocarcinoma included computed tomography (CT) of the chest, abdomen, and pelvis; urologic consultation with cystoscopy; and a screening colonoscopy. The CT scan revealed multiple enlarged inguinal and external iliac lymph nodes. Fine-needle aspiration revealed CK7- and CEA-positive neoplastic cells consistent with metastatic EMPD. The patient was treated with 6 cycles of carboplatin-paclitaxel, palliative radiation therapy, and pembrolizumab with minimal response to treatment and development of osteolytic vertebral lesions concerning for disease progression. He died 1 year after the initial diagnosis secondary to the disease.

Patient 2—A 79-year-old White man presented for further management of an outside diagnosis of superficially invasive primary EMPD of the bilateral inguinal folds and scrotum that had been present for 5 months prior to biopsy and diagnosis. Clinical examination at initial presentation revealed erythematous patches of the bilateral inguinal folds and scrotum, as well as an erythematous scaling plaque in the right axilla. There was no palpable clinical lymphadenopathy. Biopsy of the axilla and groin were both consistent with invasive EMPD with positive staining for CK7 and negative staining for CK20 and CDX2. Workup for underlying adenocarcinoma with whole-body positron emission tomography/CT, mammography, esophagogastroduodenoscopy, serum CEA, colonoscopy, and cystoscopy were all negative for a metastatic adenocarcinoma. There was no imaging or clinical evidence of lymphadenopathy. Complete circumferential peripheral and deep-margin assessment was performed in a staged manner on both sites, and negative margins were obtained.

Surveillance imaging 6 months after surgery revealed suspicious hepatic lesions. Fine-needle aspiration of the hepatic lesions demonstrated positive staining for CK7 and negative staining for CK20, CDX2, prostate-specific antigen, and thyroid transcription factor 1, consistent with metastatic EMPD. Oncology recommended carboplatin and docetaxel or docetaxel monotherapy chemotherapy. The patient was further managed by an outside oncologist due to ease of travel but died secondary to the disease 15 months following the initial diagnosis.

Comment

Extramammary Paget disease is an uncommon cutaneous malignancy that manifests as pruritic erythematous plaques within apocrine-rich areas such as the genitalia, axillae, or anal region. It most commonly occurs in patients older than 65 years, with White women and Asian men being affected at disproportionately higher rates.^1,4 Delay in diagnosis is common, as EMPD can mimic other benign inflammatory or infectious conditions, including contact dermatitis, seborrheic dermatitis, tinea, candidiasis, and eczema.¹

Metastatic and multifocal cases of primary EMPD are especially rare. According to a search of PubMed articles indexed for MEDLINE published through December 2023 using the terms extramammary Paget disease, EMPD, neoplasm metastasis, invasive extramammary, and neoplasm invasiveness, we identified 5040 cases of invasive EMPD and 477 cases of metastatic EMPD.^5-37 Of the reports that disclosed patient demographic information, 3627 patients were female 1410 were male, and the mean age was 67 years. Sites of metastases included regional lymph nodes, liver, lungs, cervix, bladder, bone, brain, skin, kidney, and adrenal glands

Workup for EMPD—The initial steps for workup of EMPD include a thorough physical examination and lymph node assessment. A skin biopsy also should be performed for patients presenting with refractory, pruritic, and eczematous rashes in apocrine-rich areas to evaluate for EMPD.¹ Characterization of large and complex tumors is better achieved through multiple biopsies with particular focus on nodular or thickened areas, as these may indicate invasive disease.² Primary EMPD is characterized by pagetoid cells with abundant pale cytoplasm proliferating in a single-cell or nested pattern within the epidermis or dermis in invasive disease and often is accompanied by dermal lymphocytic inflammation.¹ Immunohistochemistry demonstrates positive staining for CEA, CK7, and CK8, with negative staining for indicators of secondary EMPD including CK20 and CDX2.^1,2

As part of the workup, it is critical to distinguish between primary disease and secondary EMPD.¹ Beyond skin and clinical lymph node examination, additional workup should be based on age-appropriate and location-directed malignant neoplasm screenings, including colonoscopy, cystoscopy, prostate examination, mammography, and Papanicolaou test. Advanced imaging such as CT, positron emission tomography, or magnetic resonance imaging can be used to assess for metastatic disease if internal malignant neoplasms are present on initial screening or clinical lymphadenopathy is identified.² Additionally, it can be helpful in the evaluation for nodal disease in cases of invasive EMPD.

The likelihood of associated underlying carcinomas varies depending on the site of involvement.^38,39 For example, vulvar involvement constitutes approximately 65% of EMPD cases, with 11% to 20% of cases being associated with underlying gastrointestinal or genitourinary carcinomas. Involvement of the male genitalia, as in our 2 patients, is rare, accounting for approximately 14% of cases, 11% of which are associated with prostate, testicular, and bladder carcinoma. Perianal involvement comprises 20% of EMPD cases and has the greatest risk for underlying malignancy with an incidence of 33% to 86%, the majority of which are rectal or tubo-ovarian cancers.^38,39 Consideration of the frequency and types of underlying carcinoma of respective sites of involvement can be helpful when ruling out secondary EMPD.

In both of our patients, palpable lymphadenopathy at the time of original diagnosis and histologic invasive disease on initial biopsy warranted thorough imaging and laboratory workup; there was no evidence of primary malignancy. Given the absence of an underlying carcinoma, both patients were classified as having metastatic primary EMPD.

Assessment of lymphadenopathy is an essential aspect of disease workup, as it is associated with a statistically higher rate of lymph node metastases. A study by Fujisawa et al²⁰ demonstrated that 80% of patients with lymphadenopathy had regional metastases compared to only 15% of patients without clinical lymphadenopathy. The presence of invasive disease also has been shown to correspond with lymph node metastases.⁴⁰ Ogata et al⁴⁰ showed that 0% of cases with in situ EMPD had a positive sentinel lymph node biopsy (SLNB) compared to 4% and 43% in cases that showed evidence of microinvasion and dermal invasion, respectively. Lymph node metastases are associated with poor prognosis, with increasingly worse prognosis when there are multiple lymph nodes affected.⁴¹ In our case series, patient 1 had lymphadenopathy and both patients had invasive EMPD; they both later developed metastases and died.

Lymphadenopathy should be further investigated with imaging and biopsy or fine-needle aspiration.⁴² Recent expert consensus guidelines recommended this method of investigation over routine use of SLNB, as there is no evidence that a positive SLNB affects treatment that changes disease-specific survival.²

Treatment of EMPD—Surgical excision of the primary lesion is the first-line treatment of EMPD,^1,2 which can be performed by wide local excision; however, studies have demonstrated higher recurrence-free survival with margin-controlled surgery (complete circumferential peripheral and deep margin assessment) or Mohs micrographic surgery (MMS), especially with CK7 immunostaining.^2,37,43 The literature on MMS of invasive EMPD is sparse, accounting for 57 patients.^25,37,44 Other reports describe management with surgical excision, wide local excision, regional resection, or vulvectomy, in addition to lymph node dissection, radiation therapy (RT), and/or chemotherapy.^{1-36,39,43-46} Despite the improved outcomes with MMS, the predominance of other surgical approaches in our search suggests that MMS may be currently underutilized for the treatment of invasive or locally advanced EMPD.

Among patients with unresectable disease or distant metastases, management includes RT with curative intent, chemotherapy, or a combination of both.^1,2 In our review, 267 cases were treated using RT and 77 with chemotherapy. Radiation therapy is an effective therapeutic option with a reported response rate of 62% to 100% and can be employed as either primary or adjuvant treatment.³ For patients with lymph node metastasis the combination of RT and lymph node dissection has been shown to have improved outcomes compared to lymph node dissection alone, with 1 study showing a 5-year survival of 75% for patients who received adjuvant RT compared to 0% for lymph node dissection alone.⁴⁵

There are currently no consensus guidelines on the best chemotherapeutic regimen for metastatic EMPD. Several regimens have been reported, including docetaxel monotherapy; low-dose 5-fluorouracil and cisplatin; combination chemotherapy FECOM (5-fluorouracil, epirubicin, carboplatin, vincristine, mitomycin); or combination therapy with cisplatin, epirubicin, and paclitaxel.¹

Prognosis of Metastatic EMPD—Because invasive and metastatic EMPD is rare, its natural history is hard to predict. Poor prognosis is associated with nodule formation, tumor thickness, perianal or vaginal involvement, lymphovascular invasion, nodal metastasis, and distant metastasis. The 5-year survival for metastatic EMPD has been reported to be less than 10%.⁴⁶ Our cases underscore the poor prognostic risk associated with metastatic EMPD.

For all cases of EMPD, close follow-up is warranted. Guidelines recommend physical examination with lymph node assessment every 3 to 6 months for 3 years and every 6 to 12 months for the subsequent 5 years.² Specific recommendations for follow-up in invasive disease have not yet been described, though the 20% probability of developing an internal malignancy within 5 years after diagnosis and poor prognostic outcomes associated with invasive and metastatic disease support the need for close monitoring.²

Conclusion

Although in situ EMPD often is a slow-growing tumor with good prognosis, invasive disease has high potential to behave aggressively with high morbidity and mortality. Increased awareness and prompt identification of invasive EMPD, expedited comprehensive workup, and early multidisciplinary management might impact patient outcomes.

Acknowledgment—The authors would like to thank Ellen Aaronson, MLIS, AHIP (Mayo Clinic Libraries [Jacksonville, FL]), for creating and conducting the narrative literature search in the MEDLINE database.

Extramammary Paget disease (EMPD) is a rare cutaneous malignancy typically seen in apocrine-rich areas, including the axillae and anogenital region. It presents as a slow-growing, erythematous patch or plaque that commonly is misdiagnosed as an infectious or inflammatory condition.^1,2 Primary EMPD occurs as a intraepithelial neoplasm, whereas secondary EMPD occurs due to epidermotropic metastases or direct extension of an underlying adenocarcinoma into the skin.¹ Most commonly, primary EMPD occurs in situ; however, when present, dermal invasion and metastases from the skin are associated with poorer outcomes.³ Given the rarity of metastatic disease, existing literature is limited to case reports and case series.

We present 2 patients with metastatic primary EMPD who had evidence of invasion on initial biopsy and died secondary to metastatic EMPD. We conducted a comprehensive review of the literature for invasive and metastatic EMPD to highlight key clinicopathologic features, treatment considerations, and the potential for rapid disease progression in cases of invasive EMPD.

Case Series

Patient 1—A 68-year-old White man with a history of breast cancer (in remission) presented to our clinic for further management of biopsy-proven scrotal EMPD. Prior to biopsy, he described a 6-month history of worsening scrotal rash treated with topical antifungals, oral antibiotics, and topical steroids due to presumed diagnosis of intertrigo, cellulitis, and dermatitis, respectively. Clinical examination showed indurated, erythematous, ulcerated plaques involving the bilateral groin, genitalia, and perineum (Figure 1). Skin biopsy confirmed a diagnosis of EMPD with both dermal and lymphovascular invasion. An immunohistochemical profile was positive for CK7 and carcinoembryonic antigen (CEA) and negative for CK20 (Figure 2).

At presentation, the patient had palpable lymphadenopathy and scrotal edema concerning for inguinal and iliac lymph node metastases. Workup for an underlying adenocarcinoma included computed tomography (CT) of the chest, abdomen, and pelvis; urologic consultation with cystoscopy; and a screening colonoscopy. The CT scan revealed multiple enlarged inguinal and external iliac lymph nodes. Fine-needle aspiration revealed CK7- and CEA-positive neoplastic cells consistent with metastatic EMPD. The patient was treated with 6 cycles of carboplatin-paclitaxel, palliative radiation therapy, and pembrolizumab with minimal response to treatment and development of osteolytic vertebral lesions concerning for disease progression. He died 1 year after the initial diagnosis secondary to the disease.

Patient 2—A 79-year-old White man presented for further management of an outside diagnosis of superficially invasive primary EMPD of the bilateral inguinal folds and scrotum that had been present for 5 months prior to biopsy and diagnosis. Clinical examination at initial presentation revealed erythematous patches of the bilateral inguinal folds and scrotum, as well as an erythematous scaling plaque in the right axilla. There was no palpable clinical lymphadenopathy. Biopsy of the axilla and groin were both consistent with invasive EMPD with positive staining for CK7 and negative staining for CK20 and CDX2. Workup for underlying adenocarcinoma with whole-body positron emission tomography/CT, mammography, esophagogastroduodenoscopy, serum CEA, colonoscopy, and cystoscopy were all negative for a metastatic adenocarcinoma. There was no imaging or clinical evidence of lymphadenopathy. Complete circumferential peripheral and deep-margin assessment was performed in a staged manner on both sites, and negative margins were obtained.

Surveillance imaging 6 months after surgery revealed suspicious hepatic lesions. Fine-needle aspiration of the hepatic lesions demonstrated positive staining for CK7 and negative staining for CK20, CDX2, prostate-specific antigen, and thyroid transcription factor 1, consistent with metastatic EMPD. Oncology recommended carboplatin and docetaxel or docetaxel monotherapy chemotherapy. The patient was further managed by an outside oncologist due to ease of travel but died secondary to the disease 15 months following the initial diagnosis.

Comment

Extramammary Paget disease is an uncommon cutaneous malignancy that manifests as pruritic erythematous plaques within apocrine-rich areas such as the genitalia, axillae, or anal region. It most commonly occurs in patients older than 65 years, with White women and Asian men being affected at disproportionately higher rates.^1,4 Delay in diagnosis is common, as EMPD can mimic other benign inflammatory or infectious conditions, including contact dermatitis, seborrheic dermatitis, tinea, candidiasis, and eczema.¹

Metastatic and multifocal cases of primary EMPD are especially rare. According to a search of PubMed articles indexed for MEDLINE published through December 2023 using the terms extramammary Paget disease, EMPD, neoplasm metastasis, invasive extramammary, and neoplasm invasiveness, we identified 5040 cases of invasive EMPD and 477 cases of metastatic EMPD.^5-37 Of the reports that disclosed patient demographic information, 3627 patients were female 1410 were male, and the mean age was 67 years. Sites of metastases included regional lymph nodes, liver, lungs, cervix, bladder, bone, brain, skin, kidney, and adrenal glands

Workup for EMPD—The initial steps for workup of EMPD include a thorough physical examination and lymph node assessment. A skin biopsy also should be performed for patients presenting with refractory, pruritic, and eczematous rashes in apocrine-rich areas to evaluate for EMPD.¹ Characterization of large and complex tumors is better achieved through multiple biopsies with particular focus on nodular or thickened areas, as these may indicate invasive disease.² Primary EMPD is characterized by pagetoid cells with abundant pale cytoplasm proliferating in a single-cell or nested pattern within the epidermis or dermis in invasive disease and often is accompanied by dermal lymphocytic inflammation.¹ Immunohistochemistry demonstrates positive staining for CEA, CK7, and CK8, with negative staining for indicators of secondary EMPD including CK20 and CDX2.^1,2

As part of the workup, it is critical to distinguish between primary disease and secondary EMPD.¹ Beyond skin and clinical lymph node examination, additional workup should be based on age-appropriate and location-directed malignant neoplasm screenings, including colonoscopy, cystoscopy, prostate examination, mammography, and Papanicolaou test. Advanced imaging such as CT, positron emission tomography, or magnetic resonance imaging can be used to assess for metastatic disease if internal malignant neoplasms are present on initial screening or clinical lymphadenopathy is identified.² Additionally, it can be helpful in the evaluation for nodal disease in cases of invasive EMPD.

The likelihood of associated underlying carcinomas varies depending on the site of involvement.^38,39 For example, vulvar involvement constitutes approximately 65% of EMPD cases, with 11% to 20% of cases being associated with underlying gastrointestinal or genitourinary carcinomas. Involvement of the male genitalia, as in our 2 patients, is rare, accounting for approximately 14% of cases, 11% of which are associated with prostate, testicular, and bladder carcinoma. Perianal involvement comprises 20% of EMPD cases and has the greatest risk for underlying malignancy with an incidence of 33% to 86%, the majority of which are rectal or tubo-ovarian cancers.^38,39 Consideration of the frequency and types of underlying carcinoma of respective sites of involvement can be helpful when ruling out secondary EMPD.

In both of our patients, palpable lymphadenopathy at the time of original diagnosis and histologic invasive disease on initial biopsy warranted thorough imaging and laboratory workup; there was no evidence of primary malignancy. Given the absence of an underlying carcinoma, both patients were classified as having metastatic primary EMPD.

Assessment of lymphadenopathy is an essential aspect of disease workup, as it is associated with a statistically higher rate of lymph node metastases. A study by Fujisawa et al²⁰ demonstrated that 80% of patients with lymphadenopathy had regional metastases compared to only 15% of patients without clinical lymphadenopathy. The presence of invasive disease also has been shown to correspond with lymph node metastases.⁴⁰ Ogata et al⁴⁰ showed that 0% of cases with in situ EMPD had a positive sentinel lymph node biopsy (SLNB) compared to 4% and 43% in cases that showed evidence of microinvasion and dermal invasion, respectively. Lymph node metastases are associated with poor prognosis, with increasingly worse prognosis when there are multiple lymph nodes affected.⁴¹ In our case series, patient 1 had lymphadenopathy and both patients had invasive EMPD; they both later developed metastases and died.

Lymphadenopathy should be further investigated with imaging and biopsy or fine-needle aspiration.⁴² Recent expert consensus guidelines recommended this method of investigation over routine use of SLNB, as there is no evidence that a positive SLNB affects treatment that changes disease-specific survival.²

Treatment of EMPD—Surgical excision of the primary lesion is the first-line treatment of EMPD,^1,2 which can be performed by wide local excision; however, studies have demonstrated higher recurrence-free survival with margin-controlled surgery (complete circumferential peripheral and deep margin assessment) or Mohs micrographic surgery (MMS), especially with CK7 immunostaining.^2,37,43 The literature on MMS of invasive EMPD is sparse, accounting for 57 patients.^25,37,44 Other reports describe management with surgical excision, wide local excision, regional resection, or vulvectomy, in addition to lymph node dissection, radiation therapy (RT), and/or chemotherapy.^{1-36,39,43-46} Despite the improved outcomes with MMS, the predominance of other surgical approaches in our search suggests that MMS may be currently underutilized for the treatment of invasive or locally advanced EMPD.

Among patients with unresectable disease or distant metastases, management includes RT with curative intent, chemotherapy, or a combination of both.^1,2 In our review, 267 cases were treated using RT and 77 with chemotherapy. Radiation therapy is an effective therapeutic option with a reported response rate of 62% to 100% and can be employed as either primary or adjuvant treatment.³ For patients with lymph node metastasis the combination of RT and lymph node dissection has been shown to have improved outcomes compared to lymph node dissection alone, with 1 study showing a 5-year survival of 75% for patients who received adjuvant RT compared to 0% for lymph node dissection alone.⁴⁵

There are currently no consensus guidelines on the best chemotherapeutic regimen for metastatic EMPD. Several regimens have been reported, including docetaxel monotherapy; low-dose 5-fluorouracil and cisplatin; combination chemotherapy FECOM (5-fluorouracil, epirubicin, carboplatin, vincristine, mitomycin); or combination therapy with cisplatin, epirubicin, and paclitaxel.¹

Prognosis of Metastatic EMPD—Because invasive and metastatic EMPD is rare, its natural history is hard to predict. Poor prognosis is associated with nodule formation, tumor thickness, perianal or vaginal involvement, lymphovascular invasion, nodal metastasis, and distant metastasis. The 5-year survival for metastatic EMPD has been reported to be less than 10%.⁴⁶ Our cases underscore the poor prognostic risk associated with metastatic EMPD.

For all cases of EMPD, close follow-up is warranted. Guidelines recommend physical examination with lymph node assessment every 3 to 6 months for 3 years and every 6 to 12 months for the subsequent 5 years.² Specific recommendations for follow-up in invasive disease have not yet been described, though the 20% probability of developing an internal malignancy within 5 years after diagnosis and poor prognostic outcomes associated with invasive and metastatic disease support the need for close monitoring.²

Conclusion

Although in situ EMPD often is a slow-growing tumor with good prognosis, invasive disease has high potential to behave aggressively with high morbidity and mortality. Increased awareness and prompt identification of invasive EMPD, expedited comprehensive workup, and early multidisciplinary management might impact patient outcomes.

Acknowledgment—The authors would like to thank Ellen Aaronson, MLIS, AHIP (Mayo Clinic Libraries [Jacksonville, FL]), for creating and conducting the narrative literature search in the MEDLINE database.

Extramammary Paget disease (EMPD) is a rare cutaneous malignancy typically seen in apocrine-rich areas, including the axillae and anogenital region. It presents as a slow-growing, erythematous patch or plaque that commonly is misdiagnosed as an infectious or inflammatory condition.^1,2 Primary EMPD occurs as a intraepithelial neoplasm, whereas secondary EMPD occurs due to epidermotropic metastases or direct extension of an underlying adenocarcinoma into the skin.¹ Most commonly, primary EMPD occurs in situ; however, when present, dermal invasion and metastases from the skin are associated with poorer outcomes.³ Given the rarity of metastatic disease, existing literature is limited to case reports and case series.

We present 2 patients with metastatic primary EMPD who had evidence of invasion on initial biopsy and died secondary to metastatic EMPD. We conducted a comprehensive review of the literature for invasive and metastatic EMPD to highlight key clinicopathologic features, treatment considerations, and the potential for rapid disease progression in cases of invasive EMPD.

Case Series

Patient 1—A 68-year-old White man with a history of breast cancer (in remission) presented to our clinic for further management of biopsy-proven scrotal EMPD. Prior to biopsy, he described a 6-month history of worsening scrotal rash treated with topical antifungals, oral antibiotics, and topical steroids due to presumed diagnosis of intertrigo, cellulitis, and dermatitis, respectively. Clinical examination showed indurated, erythematous, ulcerated plaques involving the bilateral groin, genitalia, and perineum (Figure 1). Skin biopsy confirmed a diagnosis of EMPD with both dermal and lymphovascular invasion. An immunohistochemical profile was positive for CK7 and carcinoembryonic antigen (CEA) and negative for CK20 (Figure 2).

At presentation, the patient had palpable lymphadenopathy and scrotal edema concerning for inguinal and iliac lymph node metastases. Workup for an underlying adenocarcinoma included computed tomography (CT) of the chest, abdomen, and pelvis; urologic consultation with cystoscopy; and a screening colonoscopy. The CT scan revealed multiple enlarged inguinal and external iliac lymph nodes. Fine-needle aspiration revealed CK7- and CEA-positive neoplastic cells consistent with metastatic EMPD. The patient was treated with 6 cycles of carboplatin-paclitaxel, palliative radiation therapy, and pembrolizumab with minimal response to treatment and development of osteolytic vertebral lesions concerning for disease progression. He died 1 year after the initial diagnosis secondary to the disease.

Patient 2—A 79-year-old White man presented for further management of an outside diagnosis of superficially invasive primary EMPD of the bilateral inguinal folds and scrotum that had been present for 5 months prior to biopsy and diagnosis. Clinical examination at initial presentation revealed erythematous patches of the bilateral inguinal folds and scrotum, as well as an erythematous scaling plaque in the right axilla. There was no palpable clinical lymphadenopathy. Biopsy of the axilla and groin were both consistent with invasive EMPD with positive staining for CK7 and negative staining for CK20 and CDX2. Workup for underlying adenocarcinoma with whole-body positron emission tomography/CT, mammography, esophagogastroduodenoscopy, serum CEA, colonoscopy, and cystoscopy were all negative for a metastatic adenocarcinoma. There was no imaging or clinical evidence of lymphadenopathy. Complete circumferential peripheral and deep-margin assessment was performed in a staged manner on both sites, and negative margins were obtained.

Surveillance imaging 6 months after surgery revealed suspicious hepatic lesions. Fine-needle aspiration of the hepatic lesions demonstrated positive staining for CK7 and negative staining for CK20, CDX2, prostate-specific antigen, and thyroid transcription factor 1, consistent with metastatic EMPD. Oncology recommended carboplatin and docetaxel or docetaxel monotherapy chemotherapy. The patient was further managed by an outside oncologist due to ease of travel but died secondary to the disease 15 months following the initial diagnosis.

Comment

Extramammary Paget disease is an uncommon cutaneous malignancy that manifests as pruritic erythematous plaques within apocrine-rich areas such as the genitalia, axillae, or anal region. It most commonly occurs in patients older than 65 years, with White women and Asian men being affected at disproportionately higher rates.^1,4 Delay in diagnosis is common, as EMPD can mimic other benign inflammatory or infectious conditions, including contact dermatitis, seborrheic dermatitis, tinea, candidiasis, and eczema.¹

Metastatic and multifocal cases of primary EMPD are especially rare. According to a search of PubMed articles indexed for MEDLINE published through December 2023 using the terms extramammary Paget disease, EMPD, neoplasm metastasis, invasive extramammary, and neoplasm invasiveness, we identified 5040 cases of invasive EMPD and 477 cases of metastatic EMPD.^5-37 Of the reports that disclosed patient demographic information, 3627 patients were female 1410 were male, and the mean age was 67 years. Sites of metastases included regional lymph nodes, liver, lungs, cervix, bladder, bone, brain, skin, kidney, and adrenal glands

Workup for EMPD—The initial steps for workup of EMPD include a thorough physical examination and lymph node assessment. A skin biopsy also should be performed for patients presenting with refractory, pruritic, and eczematous rashes in apocrine-rich areas to evaluate for EMPD.¹ Characterization of large and complex tumors is better achieved through multiple biopsies with particular focus on nodular or thickened areas, as these may indicate invasive disease.² Primary EMPD is characterized by pagetoid cells with abundant pale cytoplasm proliferating in a single-cell or nested pattern within the epidermis or dermis in invasive disease and often is accompanied by dermal lymphocytic inflammation.¹ Immunohistochemistry demonstrates positive staining for CEA, CK7, and CK8, with negative staining for indicators of secondary EMPD including CK20 and CDX2.^1,2

As part of the workup, it is critical to distinguish between primary disease and secondary EMPD.¹ Beyond skin and clinical lymph node examination, additional workup should be based on age-appropriate and location-directed malignant neoplasm screenings, including colonoscopy, cystoscopy, prostate examination, mammography, and Papanicolaou test. Advanced imaging such as CT, positron emission tomography, or magnetic resonance imaging can be used to assess for metastatic disease if internal malignant neoplasms are present on initial screening or clinical lymphadenopathy is identified.² Additionally, it can be helpful in the evaluation for nodal disease in cases of invasive EMPD.

The likelihood of associated underlying carcinomas varies depending on the site of involvement.^38,39 For example, vulvar involvement constitutes approximately 65% of EMPD cases, with 11% to 20% of cases being associated with underlying gastrointestinal or genitourinary carcinomas. Involvement of the male genitalia, as in our 2 patients, is rare, accounting for approximately 14% of cases, 11% of which are associated with prostate, testicular, and bladder carcinoma. Perianal involvement comprises 20% of EMPD cases and has the greatest risk for underlying malignancy with an incidence of 33% to 86%, the majority of which are rectal or tubo-ovarian cancers.^38,39 Consideration of the frequency and types of underlying carcinoma of respective sites of involvement can be helpful when ruling out secondary EMPD.

In both of our patients, palpable lymphadenopathy at the time of original diagnosis and histologic invasive disease on initial biopsy warranted thorough imaging and laboratory workup; there was no evidence of primary malignancy. Given the absence of an underlying carcinoma, both patients were classified as having metastatic primary EMPD.

Assessment of lymphadenopathy is an essential aspect of disease workup, as it is associated with a statistically higher rate of lymph node metastases. A study by Fujisawa et al²⁰ demonstrated that 80% of patients with lymphadenopathy had regional metastases compared to only 15% of patients without clinical lymphadenopathy. The presence of invasive disease also has been shown to correspond with lymph node metastases.⁴⁰ Ogata et al⁴⁰ showed that 0% of cases with in situ EMPD had a positive sentinel lymph node biopsy (SLNB) compared to 4% and 43% in cases that showed evidence of microinvasion and dermal invasion, respectively. Lymph node metastases are associated with poor prognosis, with increasingly worse prognosis when there are multiple lymph nodes affected.⁴¹ In our case series, patient 1 had lymphadenopathy and both patients had invasive EMPD; they both later developed metastases and died.

Lymphadenopathy should be further investigated with imaging and biopsy or fine-needle aspiration.⁴² Recent expert consensus guidelines recommended this method of investigation over routine use of SLNB, as there is no evidence that a positive SLNB affects treatment that changes disease-specific survival.²

Treatment of EMPD—Surgical excision of the primary lesion is the first-line treatment of EMPD,^1,2 which can be performed by wide local excision; however, studies have demonstrated higher recurrence-free survival with margin-controlled surgery (complete circumferential peripheral and deep margin assessment) or Mohs micrographic surgery (MMS), especially with CK7 immunostaining.^2,37,43 The literature on MMS of invasive EMPD is sparse, accounting for 57 patients.^25,37,44 Other reports describe management with surgical excision, wide local excision, regional resection, or vulvectomy, in addition to lymph node dissection, radiation therapy (RT), and/or chemotherapy.^{1-36,39,43-46} Despite the improved outcomes with MMS, the predominance of other surgical approaches in our search suggests that MMS may be currently underutilized for the treatment of invasive or locally advanced EMPD.

Among patients with unresectable disease or distant metastases, management includes RT with curative intent, chemotherapy, or a combination of both.^1,2 In our review, 267 cases were treated using RT and 77 with chemotherapy. Radiation therapy is an effective therapeutic option with a reported response rate of 62% to 100% and can be employed as either primary or adjuvant treatment.³ For patients with lymph node metastasis the combination of RT and lymph node dissection has been shown to have improved outcomes compared to lymph node dissection alone, with 1 study showing a 5-year survival of 75% for patients who received adjuvant RT compared to 0% for lymph node dissection alone.⁴⁵

There are currently no consensus guidelines on the best chemotherapeutic regimen for metastatic EMPD. Several regimens have been reported, including docetaxel monotherapy; low-dose 5-fluorouracil and cisplatin; combination chemotherapy FECOM (5-fluorouracil, epirubicin, carboplatin, vincristine, mitomycin); or combination therapy with cisplatin, epirubicin, and paclitaxel.¹

Prognosis of Metastatic EMPD—Because invasive and metastatic EMPD is rare, its natural history is hard to predict. Poor prognosis is associated with nodule formation, tumor thickness, perianal or vaginal involvement, lymphovascular invasion, nodal metastasis, and distant metastasis. The 5-year survival for metastatic EMPD has been reported to be less than 10%.⁴⁶ Our cases underscore the poor prognostic risk associated with metastatic EMPD.

For all cases of EMPD, close follow-up is warranted. Guidelines recommend physical examination with lymph node assessment every 3 to 6 months for 3 years and every 6 to 12 months for the subsequent 5 years.² Specific recommendations for follow-up in invasive disease have not yet been described, though the 20% probability of developing an internal malignancy within 5 years after diagnosis and poor prognostic outcomes associated with invasive and metastatic disease support the need for close monitoring.²

Conclusion

Although in situ EMPD often is a slow-growing tumor with good prognosis, invasive disease has high potential to behave aggressively with high morbidity and mortality. Increased awareness and prompt identification of invasive EMPD, expedited comprehensive workup, and early multidisciplinary management might impact patient outcomes.

Acknowledgment—The authors would like to thank Ellen Aaronson, MLIS, AHIP (Mayo Clinic Libraries [Jacksonville, FL]), for creating and conducting the narrative literature search in the MEDLINE database.

THE DIAGNOSIS: Coexisting Squamous Cell Carcinoma and Basal Cell Carcinoma

Dermoscopy of the plaque showed central ulceration with blood spots surrounded by branched linear vessels, which was suggestive of squamous cell carcinoma (SCC)(Figure 1A). The nodule showed shiny, white-red, structureless areas with small gray spots, bright white crystalline streaks, and short fine telangiectasias suggestive of basal cell carcinoma (BCC)(Figure 1B). Histopathology showed that the plaque had irregular nests, cords, and sheets of neoplastic keratinocytes invading the dermis (Figure 2A) and the nodule had discrete nests of basaloid cells with peripheral palisading in the dermis (Figure 2B), which confirmed the diagnosis of coexisting SCC and BCC. The patient underwent surgical excision of the lesions, which achieved clear margins. At the 2-year follow-up, there was no sign of recurrence.

Squamous cell carcinoma is the second most frequent cancer in humans. Older patients are more susceptible due to chronic UV exposure.¹ Basal cell carcinoma is the most common human cancer worldwide.² These skin cancers have different clinical manifestations, pathologic features, treatment methods, and prognoses. The coexistence of 2 types of skin cancer presents a diagnostic challenge. Possible causes of this phenomenon are not clear. It may simply be a coincidence since the lesions typically occur in sun-exposed areas such as the nose, which may be affected by photodamage.³ According to the field cancerization theory, chronically sun-exposed areas are at higher risk for development of coexisting skin cancers.⁴ A more interesting explanation is the interaction theory, which suggests that one tumor produces epidermal or stromal changes that induce the formation of a second independent tumor via the paracrine effect (ie, growth mediators from nearby cells).⁴

Dermoscopy is an important noninvasive diagnostic tool for the evaluation of skin cancer, particularly early detection. Dermoscopic findings of blood vessels, ulcers, the fiber sign, blood spots, white structureless areas, keratin, and centered vessels indicate a diagnosis of SCC.⁵ In contrast, common dermoscopic findings for BCC include arborizing vessels, ulceration, shiny white structures, and blue-gray ovoid nests or globules.⁶

Irritated seborrheic keratosis is an inflammatory variant of seborrheic keratosis, which often is challenging to identify clinically due to its similar features with SCC; however, SCC is more likely to demonstrate dotted or branched vessels, white structureless areas, white circles around follicles, irregular or peripheral vessel patterns, and central scales on dermoscopy. In contrast, irritated seborrheic keratosis is more likely to have hairpin vessels, regular vessel patterns, and white halos around vessels, which may aid in the differentiation between the two entities.⁶

Due to the higher sensitivity of dermoscopy for detecting pigmented BCC compared to nonpigmented BCC, it holds substantial diagnostic value in Asian populations, in whom pigmented BCC is the most common subtype.^6,8 However, the lack of pigmentation in the nodule in our case posed a diagnostic challenge, as the diagnosis of BCC had to rely on subtle vascular and shiny white structures rather than more obvious pigment clues. This absence of pigment, however, also helped rule out pigmented BCC as a diagnosis for the nodule. Short fine telangiectasias is the second most common vascular pattern in BCC, and bright white structures are highly suggestive of nonpigmented BCC.⁶ Therefore, dermoscopic findings of bright-white structures with fine telangiectasias should be alerted to the possibility of nonpigmented BCC.

Basosquamous carcinoma has clinical and dermoscopic features between SCC and BCC, and the presence of dermatoscopic features from both BCC and SCC should raise suspicion, but the diagnosis is particularly challenging because its presentation is nonspecific.⁹ We need to be vigilant about the possibility of coexistence of 2 types of skin cancer, and that regular physical examination and dermatoscopy are very important for early detection and diagnosis.

THE DIAGNOSIS: Coexisting Squamous Cell Carcinoma and Basal Cell Carcinoma

Dermoscopy of the plaque showed central ulceration with blood spots surrounded by branched linear vessels, which was suggestive of squamous cell carcinoma (SCC)(Figure 1A). The nodule showed shiny, white-red, structureless areas with small gray spots, bright white crystalline streaks, and short fine telangiectasias suggestive of basal cell carcinoma (BCC)(Figure 1B). Histopathology showed that the plaque had irregular nests, cords, and sheets of neoplastic keratinocytes invading the dermis (Figure 2A) and the nodule had discrete nests of basaloid cells with peripheral palisading in the dermis (Figure 2B), which confirmed the diagnosis of coexisting SCC and BCC. The patient underwent surgical excision of the lesions, which achieved clear margins. At the 2-year follow-up, there was no sign of recurrence.

Squamous cell carcinoma is the second most frequent cancer in humans. Older patients are more susceptible due to chronic UV exposure.¹ Basal cell carcinoma is the most common human cancer worldwide.² These skin cancers have different clinical manifestations, pathologic features, treatment methods, and prognoses. The coexistence of 2 types of skin cancer presents a diagnostic challenge. Possible causes of this phenomenon are not clear. It may simply be a coincidence since the lesions typically occur in sun-exposed areas such as the nose, which may be affected by photodamage.³ According to the field cancerization theory, chronically sun-exposed areas are at higher risk for development of coexisting skin cancers.⁴ A more interesting explanation is the interaction theory, which suggests that one tumor produces epidermal or stromal changes that induce the formation of a second independent tumor via the paracrine effect (ie, growth mediators from nearby cells).⁴

Dermoscopy is an important noninvasive diagnostic tool for the evaluation of skin cancer, particularly early detection. Dermoscopic findings of blood vessels, ulcers, the fiber sign, blood spots, white structureless areas, keratin, and centered vessels indicate a diagnosis of SCC.⁵ In contrast, common dermoscopic findings for BCC include arborizing vessels, ulceration, shiny white structures, and blue-gray ovoid nests or globules.⁶

Irritated seborrheic keratosis is an inflammatory variant of seborrheic keratosis, which often is challenging to identify clinically due to its similar features with SCC; however, SCC is more likely to demonstrate dotted or branched vessels, white structureless areas, white circles around follicles, irregular or peripheral vessel patterns, and central scales on dermoscopy. In contrast, irritated seborrheic keratosis is more likely to have hairpin vessels, regular vessel patterns, and white halos around vessels, which may aid in the differentiation between the two entities.⁶

Due to the higher sensitivity of dermoscopy for detecting pigmented BCC compared to nonpigmented BCC, it holds substantial diagnostic value in Asian populations, in whom pigmented BCC is the most common subtype.^6,8 However, the lack of pigmentation in the nodule in our case posed a diagnostic challenge, as the diagnosis of BCC had to rely on subtle vascular and shiny white structures rather than more obvious pigment clues. This absence of pigment, however, also helped rule out pigmented BCC as a diagnosis for the nodule. Short fine telangiectasias is the second most common vascular pattern in BCC, and bright white structures are highly suggestive of nonpigmented BCC.⁶ Therefore, dermoscopic findings of bright-white structures with fine telangiectasias should be alerted to the possibility of nonpigmented BCC.

Basosquamous carcinoma has clinical and dermoscopic features between SCC and BCC, and the presence of dermatoscopic features from both BCC and SCC should raise suspicion, but the diagnosis is particularly challenging because its presentation is nonspecific.⁹ We need to be vigilant about the possibility of coexistence of 2 types of skin cancer, and that regular physical examination and dermatoscopy are very important for early detection and diagnosis.

THE DIAGNOSIS: Coexisting Squamous Cell Carcinoma and Basal Cell Carcinoma

Dermoscopy of the plaque showed central ulceration with blood spots surrounded by branched linear vessels, which was suggestive of squamous cell carcinoma (SCC)(Figure 1A). The nodule showed shiny, white-red, structureless areas with small gray spots, bright white crystalline streaks, and short fine telangiectasias suggestive of basal cell carcinoma (BCC)(Figure 1B). Histopathology showed that the plaque had irregular nests, cords, and sheets of neoplastic keratinocytes invading the dermis (Figure 2A) and the nodule had discrete nests of basaloid cells with peripheral palisading in the dermis (Figure 2B), which confirmed the diagnosis of coexisting SCC and BCC. The patient underwent surgical excision of the lesions, which achieved clear margins. At the 2-year follow-up, there was no sign of recurrence.

Squamous cell carcinoma is the second most frequent cancer in humans. Older patients are more susceptible due to chronic UV exposure.¹ Basal cell carcinoma is the most common human cancer worldwide.² These skin cancers have different clinical manifestations, pathologic features, treatment methods, and prognoses. The coexistence of 2 types of skin cancer presents a diagnostic challenge. Possible causes of this phenomenon are not clear. It may simply be a coincidence since the lesions typically occur in sun-exposed areas such as the nose, which may be affected by photodamage.³ According to the field cancerization theory, chronically sun-exposed areas are at higher risk for development of coexisting skin cancers.⁴ A more interesting explanation is the interaction theory, which suggests that one tumor produces epidermal or stromal changes that induce the formation of a second independent tumor via the paracrine effect (ie, growth mediators from nearby cells).⁴

Dermoscopy is an important noninvasive diagnostic tool for the evaluation of skin cancer, particularly early detection. Dermoscopic findings of blood vessels, ulcers, the fiber sign, blood spots, white structureless areas, keratin, and centered vessels indicate a diagnosis of SCC.⁵ In contrast, common dermoscopic findings for BCC include arborizing vessels, ulceration, shiny white structures, and blue-gray ovoid nests or globules.⁶

Irritated seborrheic keratosis is an inflammatory variant of seborrheic keratosis, which often is challenging to identify clinically due to its similar features with SCC; however, SCC is more likely to demonstrate dotted or branched vessels, white structureless areas, white circles around follicles, irregular or peripheral vessel patterns, and central scales on dermoscopy. In contrast, irritated seborrheic keratosis is more likely to have hairpin vessels, regular vessel patterns, and white halos around vessels, which may aid in the differentiation between the two entities.⁶

Due to the higher sensitivity of dermoscopy for detecting pigmented BCC compared to nonpigmented BCC, it holds substantial diagnostic value in Asian populations, in whom pigmented BCC is the most common subtype.^6,8 However, the lack of pigmentation in the nodule in our case posed a diagnostic challenge, as the diagnosis of BCC had to rely on subtle vascular and shiny white structures rather than more obvious pigment clues. This absence of pigment, however, also helped rule out pigmented BCC as a diagnosis for the nodule. Short fine telangiectasias is the second most common vascular pattern in BCC, and bright white structures are highly suggestive of nonpigmented BCC.⁶ Therefore, dermoscopic findings of bright-white structures with fine telangiectasias should be alerted to the possibility of nonpigmented BCC.

Basosquamous carcinoma has clinical and dermoscopic features between SCC and BCC, and the presence of dermatoscopic features from both BCC and SCC should raise suspicion, but the diagnosis is particularly challenging because its presentation is nonspecific.⁹ We need to be vigilant about the possibility of coexistence of 2 types of skin cancer, and that regular physical examination and dermatoscopy are very important for early detection and diagnosis.

TOPLINE:

In a review of physician-related malpractice cases from 1930 to 2025, melanoma was the most frequently litigated skin cancer, and failure or delay in diagnosis was the most common allegation, with documented death in nearly one third of cases.

METHODOLOGY:

Researchers conducted a review of physician-related medicolegal cases involving skin cancer using the LexisNexis legal database and identified 188 unique cases from 1930 through May 2025.

Cases were included if physicians were named as defendants and the litigation centered on diagnosis or management of a cutaneous malignancy.

Study outcomes examined case characteristics including cancer type, practice setting, defendant specialty, primary allegations, clinical outcomes, and case verdicts across the US.

TAKEAWAY:

Melanoma accounted for 49.5% of litigated cases, followed by squamous cell carcinoma (21.6%), basal cell carcinoma (14.2%), unspecified skin cancer (11.6%), and other rare tumors (3.1%). Death was reported in 29.8% of cases and metastatic disease in 39.9%.

Failure or delay in diagnosis was the leading allegation (38.1%), followed by treatment or management errors (24.2%), misdiagnosis (11.4%), “deliberate indifference” (8.3%), inadequate informed consent (7.5%), and pathology-related errors (7.2%).

Family physicians were the most common defendants (27.5%), followed by dermatologists, including Mohs surgeons (20.1%), and pathologists or dermatopathologists (14.4%), followed by general or plastic surgeons (7.9%), and internists (4.4%). Most cases originated in private practices (59.7%), and New York (16.0%) and California (13.3%) were the states with the most cases.

Among 109 closed cases, 5.5% resulted in plaintiff verdicts, whereas defense verdicts predominated in 55.0%. Plaintiff awards ranged from $10,000 to $4.25 million.

IN PRACTICE:

“This comprehensive review demonstrates that melanoma is the most frequently litigated skin cancer, particularly in cases involving metastatic disease or death, and that family physicians are the most commonly named defendants overall,” the authors wrote. “By examining both allegations and outcomes,” they added, “this analysis provides a pragmatic assessment of real-world litigation exposure and the clinical scenarios that expose physicians to legal proceedings, financial cost, reputational harm, and psychological burden, regardless of case disposition.”

SOURCE:

The study was led by Ghassan Barnawi, MD, Division of Dermatology, McGill University in Montreal, Quebec, Canada, and was published online on February 20, 2026, in the Journal of the American Academy of Dermatology.

LIMITATIONS:

The study relied on published court decisions, which likely underestimated malpractice burden by excluding settlements and unreported claims.

DISCLOSURES:

The study did not receive any funding. The authors reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

The study had no commercial funding. The authors had no relevant disclosures.

A version of this article first appeared on Medscape.com

TOPLINE:

In a review of physician-related malpractice cases from 1930 to 2025, melanoma was the most frequently litigated skin cancer, and failure or delay in diagnosis was the most common allegation, with documented death in nearly one third of cases.

METHODOLOGY:

Researchers conducted a review of physician-related medicolegal cases involving skin cancer using the LexisNexis legal database and identified 188 unique cases from 1930 through May 2025.

Cases were included if physicians were named as defendants and the litigation centered on diagnosis or management of a cutaneous malignancy.

Study outcomes examined case characteristics including cancer type, practice setting, defendant specialty, primary allegations, clinical outcomes, and case verdicts across the US.

TAKEAWAY:

Melanoma accounted for 49.5% of litigated cases, followed by squamous cell carcinoma (21.6%), basal cell carcinoma (14.2%), unspecified skin cancer (11.6%), and other rare tumors (3.1%). Death was reported in 29.8% of cases and metastatic disease in 39.9%.

Failure or delay in diagnosis was the leading allegation (38.1%), followed by treatment or management errors (24.2%), misdiagnosis (11.4%), “deliberate indifference” (8.3%), inadequate informed consent (7.5%), and pathology-related errors (7.2%).

Family physicians were the most common defendants (27.5%), followed by dermatologists, including Mohs surgeons (20.1%), and pathologists or dermatopathologists (14.4%), followed by general or plastic surgeons (7.9%), and internists (4.4%). Most cases originated in private practices (59.7%), and New York (16.0%) and California (13.3%) were the states with the most cases.

Among 109 closed cases, 5.5% resulted in plaintiff verdicts, whereas defense verdicts predominated in 55.0%. Plaintiff awards ranged from $10,000 to $4.25 million.

IN PRACTICE:

“This comprehensive review demonstrates that melanoma is the most frequently litigated skin cancer, particularly in cases involving metastatic disease or death, and that family physicians are the most commonly named defendants overall,” the authors wrote. “By examining both allegations and outcomes,” they added, “this analysis provides a pragmatic assessment of real-world litigation exposure and the clinical scenarios that expose physicians to legal proceedings, financial cost, reputational harm, and psychological burden, regardless of case disposition.”

SOURCE:

The study was led by Ghassan Barnawi, MD, Division of Dermatology, McGill University in Montreal, Quebec, Canada, and was published online on February 20, 2026, in the Journal of the American Academy of Dermatology.

LIMITATIONS:

The study relied on published court decisions, which likely underestimated malpractice burden by excluding settlements and unreported claims.

DISCLOSURES:

The study did not receive any funding. The authors reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

The study had no commercial funding. The authors had no relevant disclosures.

A version of this article first appeared on Medscape.com

TOPLINE:

In a review of physician-related malpractice cases from 1930 to 2025, melanoma was the most frequently litigated skin cancer, and failure or delay in diagnosis was the most common allegation, with documented death in nearly one third of cases.

METHODOLOGY:

Researchers conducted a review of physician-related medicolegal cases involving skin cancer using the LexisNexis legal database and identified 188 unique cases from 1930 through May 2025.

Cases were included if physicians were named as defendants and the litigation centered on diagnosis or management of a cutaneous malignancy.

Study outcomes examined case characteristics including cancer type, practice setting, defendant specialty, primary allegations, clinical outcomes, and case verdicts across the US.

TAKEAWAY:

Melanoma accounted for 49.5% of litigated cases, followed by squamous cell carcinoma (21.6%), basal cell carcinoma (14.2%), unspecified skin cancer (11.6%), and other rare tumors (3.1%). Death was reported in 29.8% of cases and metastatic disease in 39.9%.

Failure or delay in diagnosis was the leading allegation (38.1%), followed by treatment or management errors (24.2%), misdiagnosis (11.4%), “deliberate indifference” (8.3%), inadequate informed consent (7.5%), and pathology-related errors (7.2%).

Family physicians were the most common defendants (27.5%), followed by dermatologists, including Mohs surgeons (20.1%), and pathologists or dermatopathologists (14.4%), followed by general or plastic surgeons (7.9%), and internists (4.4%). Most cases originated in private practices (59.7%), and New York (16.0%) and California (13.3%) were the states with the most cases.

Among 109 closed cases, 5.5% resulted in plaintiff verdicts, whereas defense verdicts predominated in 55.0%. Plaintiff awards ranged from $10,000 to $4.25 million.

IN PRACTICE:

“This comprehensive review demonstrates that melanoma is the most frequently litigated skin cancer, particularly in cases involving metastatic disease or death, and that family physicians are the most commonly named defendants overall,” the authors wrote. “By examining both allegations and outcomes,” they added, “this analysis provides a pragmatic assessment of real-world litigation exposure and the clinical scenarios that expose physicians to legal proceedings, financial cost, reputational harm, and psychological burden, regardless of case disposition.”

SOURCE:

The study was led by Ghassan Barnawi, MD, Division of Dermatology, McGill University in Montreal, Quebec, Canada, and was published online on February 20, 2026, in the Journal of the American Academy of Dermatology.

LIMITATIONS:

The study relied on published court decisions, which likely underestimated malpractice burden by excluding settlements and unreported claims.

DISCLOSURES:

The study did not receive any funding. The authors reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

The study had no commercial funding. The authors had no relevant disclosures.

A version of this article first appeared on Medscape.com

To the Editor:

Primary cutaneous B-cell lymphomas (pcBCLs) can clinically mimic basal cell carcinomas (BCCs); however, histopathologic examination typically demonstrates features of lymphoma without evidence of an epithelial tumor. We present the case of a patient who demonstrated histologic features of both pcBCL and BCC in the same lesion, which was discovered during Mohs micrographic surgery.

An 84-year-old man presented for Mohs surgery for a biopsy-proven nodular and infiltrative BCC on the right superior helix of the ear of 1 year’s duration. Physical examination of the ear revealed a 1.0×1.3–cm ulcerated indurated plaque with rolled borders and a central hyperkeratotic crust (Figure 1). Frozen sections from the first Mohs stage demonstrated residual superficial, infiltrative, and basosquamous BCC (Figure 2). In addition, there was a brisk inflammatory infiltrate throughout the deep margins. The second stage showed no residual BCC, but there still was a brisk atypical lymphocytic infiltrate, with some areas showing lymphocytes in a linear cordlike distribution (Figure 3). Permanent sections demonstrated infiltration of small to medium lymphoid cells. Immunohistochemistry stains were positive for CD20 and BCL2 and negative for CD5, CD10, BCL6, and CD43; a low Ki-67 proliferation fraction also was observed. B-cell clonality studies and polymerase chain reaction demonstrated rearrangements of the IgH and IgK genes, consistent with primary cutaneous marginal zone lymphoma (pcMZL). Positron emission tomography showed no spread of malignancy; therefore, medical oncology recommended observation and close monitoring.

Primary cutaneous B-cell lymphoma accounts for approximately 25% of all cutaneous lymphomas.¹ Three main cutaneous subtypes exist: pcMZL; primary cutaneous follicular center lymphoma; and primary cutaneous diffuse large B-cell lymphoma, leg type. The second most common type of cutaneous lymphoma, pcMZL, accounts for 25% of cases of pcBCL.¹ Primary cutaneous follicular center lymphoma makes up 60% of cutaneous lymphomas, and the remainder are primary cutaneous diffuse large B-cell lymphoma, leg type. All share a notable male predominance and onset most commonly in the sixth through eighth decades of life, although they also can occur in younger patients.¹

Histologically, pcMZL has 2 distinct subtypes: one resembling mucosal-associated lymphoid tissue lymphomas and a more clinically aggressive subtype with heavy chain class switching, although intermediate forms also exist. Both are characterized by diffuse and/or nodular infiltrates in the subcutis and dermis with sparing of the epidermis. Often, these infiltrates are more prominent in the deeper sections examined, and occasionally they may be accompanied by germinal center follicles. Immunohistochemical stains are key in determining the pcBCL subtype. Primary cutaneous marginal zone lymphoma will most commonly show a BCL2+, BCL6–, CD20+, and CD10– immunophenotype, as in our case. If a majority of cells have undergone plasmacytoid differentiation, loss of CD20 can occur, but retention of other B-cell markers, such as CD79a and CD19, will be seen. Proliferation fraction via Ki-67 commonly is low, reflecting the indolence of this subtype of lymphoma.¹

Monoclonal rearrangement of immunoglobulins also can occur, with IgH rearrangements detected in 60% to 80% of cases of pcMZL. Translocations are not a reliable method of diagnosis for pcMZL but can be present in a variable manner, with t(14;18), t(3;14), and t(11;18) reported in a subset of cases.² Leukemic infiltrates encountered on frozen sections should prompt the Mohs surgeon to consider the possibility of a concomitant leukemia or lymphoma. In one study, 36% (20/55) of patients with chronic lymphocytic leukemia (CLL) were found to have predominantly leukemic B-cell infiltrates on frozen sections.³ Numerous reports also exist of asymptomatic patients being diagnosed with CLL due to leukemic infiltrates identified during Mohs surgery.^4,5 Patients with systemic hematologic malignancies, including CLL and non-Hodgkin lymphoma, also are known to be at an increased risk for skin cancers, including keratinocyte cancers, melanoma, and Merkel cell carcinoma. This can be attributed partially to immunosuppression, a well-known risk factor for development of cutaneous malignancies.⁵ Padgett et al⁵ speculated that local immune suppression due to underlying pcBCL and reaction of lymphocytes to tumor antigens could have played a role in the development of BCC at this site. If a leukemic infiltrate is demonstrated, the surgeon should consider sending tissue for permanent section and immunostaining. This can be helpful to determine if it is a reactive or neoplastic process and aid in characterizing the leukemic infiltrate if it is suspected to be neoplastic in nature.

There are numerous reports of pcBCL imitating the cutaneous findings of BCC clinically, but this is quite uncommon on histopathology. As in our case, findings of sheets of dense, monomorphic lymphocytes; inability to clear inflammation on deeper Mohs sections; presence of primordial follicles; and atypical cytology, including predominance of blastic forms, plasmacytoid cells, or cleaved lymphocytes, should give the clinician pause to consider further evaluation through permanent sections as well as genetic and immunoglobulin studies by a dermatopathologist. This case highlights the importance of further evaluation when an atypical finding is encountered during Mohs surgery.

To the Editor:

Primary cutaneous B-cell lymphomas (pcBCLs) can clinically mimic basal cell carcinomas (BCCs); however, histopathologic examination typically demonstrates features of lymphoma without evidence of an epithelial tumor. We present the case of a patient who demonstrated histologic features of both pcBCL and BCC in the same lesion, which was discovered during Mohs micrographic surgery.

An 84-year-old man presented for Mohs surgery for a biopsy-proven nodular and infiltrative BCC on the right superior helix of the ear of 1 year’s duration. Physical examination of the ear revealed a 1.0×1.3–cm ulcerated indurated plaque with rolled borders and a central hyperkeratotic crust (Figure 1). Frozen sections from the first Mohs stage demonstrated residual superficial, infiltrative, and basosquamous BCC (Figure 2). In addition, there was a brisk inflammatory infiltrate throughout the deep margins. The second stage showed no residual BCC, but there still was a brisk atypical lymphocytic infiltrate, with some areas showing lymphocytes in a linear cordlike distribution (Figure 3). Permanent sections demonstrated infiltration of small to medium lymphoid cells. Immunohistochemistry stains were positive for CD20 and BCL2 and negative for CD5, CD10, BCL6, and CD43; a low Ki-67 proliferation fraction also was observed. B-cell clonality studies and polymerase chain reaction demonstrated rearrangements of the IgH and IgK genes, consistent with primary cutaneous marginal zone lymphoma (pcMZL). Positron emission tomography showed no spread of malignancy; therefore, medical oncology recommended observation and close monitoring.

Primary cutaneous B-cell lymphoma accounts for approximately 25% of all cutaneous lymphomas.¹ Three main cutaneous subtypes exist: pcMZL; primary cutaneous follicular center lymphoma; and primary cutaneous diffuse large B-cell lymphoma, leg type. The second most common type of cutaneous lymphoma, pcMZL, accounts for 25% of cases of pcBCL.¹ Primary cutaneous follicular center lymphoma makes up 60% of cutaneous lymphomas, and the remainder are primary cutaneous diffuse large B-cell lymphoma, leg type. All share a notable male predominance and onset most commonly in the sixth through eighth decades of life, although they also can occur in younger patients.¹

Histologically, pcMZL has 2 distinct subtypes: one resembling mucosal-associated lymphoid tissue lymphomas and a more clinically aggressive subtype with heavy chain class switching, although intermediate forms also exist. Both are characterized by diffuse and/or nodular infiltrates in the subcutis and dermis with sparing of the epidermis. Often, these infiltrates are more prominent in the deeper sections examined, and occasionally they may be accompanied by germinal center follicles. Immunohistochemical stains are key in determining the pcBCL subtype. Primary cutaneous marginal zone lymphoma will most commonly show a BCL2+, BCL6–, CD20+, and CD10– immunophenotype, as in our case. If a majority of cells have undergone plasmacytoid differentiation, loss of CD20 can occur, but retention of other B-cell markers, such as CD79a and CD19, will be seen. Proliferation fraction via Ki-67 commonly is low, reflecting the indolence of this subtype of lymphoma.¹

Monoclonal rearrangement of immunoglobulins also can occur, with IgH rearrangements detected in 60% to 80% of cases of pcMZL. Translocations are not a reliable method of diagnosis for pcMZL but can be present in a variable manner, with t(14;18), t(3;14), and t(11;18) reported in a subset of cases.² Leukemic infiltrates encountered on frozen sections should prompt the Mohs surgeon to consider the possibility of a concomitant leukemia or lymphoma. In one study, 36% (20/55) of patients with chronic lymphocytic leukemia (CLL) were found to have predominantly leukemic B-cell infiltrates on frozen sections.³ Numerous reports also exist of asymptomatic patients being diagnosed with CLL due to leukemic infiltrates identified during Mohs surgery.^4,5 Patients with systemic hematologic malignancies, including CLL and non-Hodgkin lymphoma, also are known to be at an increased risk for skin cancers, including keratinocyte cancers, melanoma, and Merkel cell carcinoma. This can be attributed partially to immunosuppression, a well-known risk factor for development of cutaneous malignancies.⁵ Padgett et al⁵ speculated that local immune suppression due to underlying pcBCL and reaction of lymphocytes to tumor antigens could have played a role in the development of BCC at this site. If a leukemic infiltrate is demonstrated, the surgeon should consider sending tissue for permanent section and immunostaining. This can be helpful to determine if it is a reactive or neoplastic process and aid in characterizing the leukemic infiltrate if it is suspected to be neoplastic in nature.

There are numerous reports of pcBCL imitating the cutaneous findings of BCC clinically, but this is quite uncommon on histopathology. As in our case, findings of sheets of dense, monomorphic lymphocytes; inability to clear inflammation on deeper Mohs sections; presence of primordial follicles; and atypical cytology, including predominance of blastic forms, plasmacytoid cells, or cleaved lymphocytes, should give the clinician pause to consider further evaluation through permanent sections as well as genetic and immunoglobulin studies by a dermatopathologist. This case highlights the importance of further evaluation when an atypical finding is encountered during Mohs surgery.

To the Editor:

Primary cutaneous B-cell lymphomas (pcBCLs) can clinically mimic basal cell carcinomas (BCCs); however, histopathologic examination typically demonstrates features of lymphoma without evidence of an epithelial tumor. We present the case of a patient who demonstrated histologic features of both pcBCL and BCC in the same lesion, which was discovered during Mohs micrographic surgery.

An 84-year-old man presented for Mohs surgery for a biopsy-proven nodular and infiltrative BCC on the right superior helix of the ear of 1 year’s duration. Physical examination of the ear revealed a 1.0×1.3–cm ulcerated indurated plaque with rolled borders and a central hyperkeratotic crust (Figure 1). Frozen sections from the first Mohs stage demonstrated residual superficial, infiltrative, and basosquamous BCC (Figure 2). In addition, there was a brisk inflammatory infiltrate throughout the deep margins. The second stage showed no residual BCC, but there still was a brisk atypical lymphocytic infiltrate, with some areas showing lymphocytes in a linear cordlike distribution (Figure 3). Permanent sections demonstrated infiltration of small to medium lymphoid cells. Immunohistochemistry stains were positive for CD20 and BCL2 and negative for CD5, CD10, BCL6, and CD43; a low Ki-67 proliferation fraction also was observed. B-cell clonality studies and polymerase chain reaction demonstrated rearrangements of the IgH and IgK genes, consistent with primary cutaneous marginal zone lymphoma (pcMZL). Positron emission tomography showed no spread of malignancy; therefore, medical oncology recommended observation and close monitoring.

Primary cutaneous B-cell lymphoma accounts for approximately 25% of all cutaneous lymphomas.¹ Three main cutaneous subtypes exist: pcMZL; primary cutaneous follicular center lymphoma; and primary cutaneous diffuse large B-cell lymphoma, leg type. The second most common type of cutaneous lymphoma, pcMZL, accounts for 25% of cases of pcBCL.¹ Primary cutaneous follicular center lymphoma makes up 60% of cutaneous lymphomas, and the remainder are primary cutaneous diffuse large B-cell lymphoma, leg type. All share a notable male predominance and onset most commonly in the sixth through eighth decades of life, although they also can occur in younger patients.¹

Histologically, pcMZL has 2 distinct subtypes: one resembling mucosal-associated lymphoid tissue lymphomas and a more clinically aggressive subtype with heavy chain class switching, although intermediate forms also exist. Both are characterized by diffuse and/or nodular infiltrates in the subcutis and dermis with sparing of the epidermis. Often, these infiltrates are more prominent in the deeper sections examined, and occasionally they may be accompanied by germinal center follicles. Immunohistochemical stains are key in determining the pcBCL subtype. Primary cutaneous marginal zone lymphoma will most commonly show a BCL2+, BCL6–, CD20+, and CD10– immunophenotype, as in our case. If a majority of cells have undergone plasmacytoid differentiation, loss of CD20 can occur, but retention of other B-cell markers, such as CD79a and CD19, will be seen. Proliferation fraction via Ki-67 commonly is low, reflecting the indolence of this subtype of lymphoma.¹

Monoclonal rearrangement of immunoglobulins also can occur, with IgH rearrangements detected in 60% to 80% of cases of pcMZL. Translocations are not a reliable method of diagnosis for pcMZL but can be present in a variable manner, with t(14;18), t(3;14), and t(11;18) reported in a subset of cases.² Leukemic infiltrates encountered on frozen sections should prompt the Mohs surgeon to consider the possibility of a concomitant leukemia or lymphoma. In one study, 36% (20/55) of patients with chronic lymphocytic leukemia (CLL) were found to have predominantly leukemic B-cell infiltrates on frozen sections.³ Numerous reports also exist of asymptomatic patients being diagnosed with CLL due to leukemic infiltrates identified during Mohs surgery.^4,5 Patients with systemic hematologic malignancies, including CLL and non-Hodgkin lymphoma, also are known to be at an increased risk for skin cancers, including keratinocyte cancers, melanoma, and Merkel cell carcinoma. This can be attributed partially to immunosuppression, a well-known risk factor for development of cutaneous malignancies.⁵ Padgett et al⁵ speculated that local immune suppression due to underlying pcBCL and reaction of lymphocytes to tumor antigens could have played a role in the development of BCC at this site. If a leukemic infiltrate is demonstrated, the surgeon should consider sending tissue for permanent section and immunostaining. This can be helpful to determine if it is a reactive or neoplastic process and aid in characterizing the leukemic infiltrate if it is suspected to be neoplastic in nature.

There are numerous reports of pcBCL imitating the cutaneous findings of BCC clinically, but this is quite uncommon on histopathology. As in our case, findings of sheets of dense, monomorphic lymphocytes; inability to clear inflammation on deeper Mohs sections; presence of primordial follicles; and atypical cytology, including predominance of blastic forms, plasmacytoid cells, or cleaved lymphocytes, should give the clinician pause to consider further evaluation through permanent sections as well as genetic and immunoglobulin studies by a dermatopathologist. This case highlights the importance of further evaluation when an atypical finding is encountered during Mohs surgery.

Squamous cell carcinoma (SCC) is the malignant proliferation of keratinocytes in the epidermis of the skin. Most SCCs are caused by UV light exposure, with sex and increased age acting as the primary known risk factors: SCCs are nearly twice as prevalent in men vs women, and the average age of presentation is the middle of the seventh decade of life.¹ In the United States, there are an estimated 1.8 million new SCC cases annually.² Although not usually life threatening, if left untreated, SCC can metastasize, thereby reducing the 10-year survival rate from above 90% with treatment to 16%.^3-6

Most invasive SCC lesions are treated surgically, but intralesional methotrexate (IL-MTX) has emerged as an alternative treatment for cutaneous SCC. It offers the potential for lower-cost, efficacious outpatient treatment.^7-12 Methotrexate competitively inhibits the enzyme dihydrofolate reductase, which converts dihydrofolate into tetrahydrofolate.¹³ In doing so, MTX indirectly prevents the synthesis of thymine, a nucleotide required for DNA synthesis. Thus, MTX can halt DNA synthesis and consequently, cell division. Intralesional MTX has been shown to successfully treat keratoacanthomas, lymphomas, and various inflammatory dermatologic conditions.^8-12 

Surgical options include standard excision, Mohs micrographic surgery, or electrodesiccation and curettage. Surgical treatment has high (92% to 99%) cure rates and typically requires only 1 or 2 appointments.^14,15 Although costs can vary, one 2012 study using Medicare fee schedules found that total costs (including primary procedure, biopsy, follow-up appointments through 2 months, and other associated costs) for cutaneous SCC were $475 for electrodesiccation and curettage, $1302.92 for excision, and $2093.14 for Mohs micrographic surgery.¹⁶ For some patients, surgery is not an ideal option due to the tumor location, poor wound healing, anticoagulation, and cost. In these patients, photodynamic therapy, topical therapy with 5-fluorouracil or imiquimod, radiation, and cryotherapy are options listed in the American Academy of Dermatology guidelines.¹⁵ Compared with surgery, radiation is more demanding on the patient, often requiring multiple visits a week and including common undesirable adverse effects such as radiation dermatitis and prolonged wounds on the lower legs.¹⁷ Radiation also can be costly, with one study reporting costs between $2559 and $3431 for SCC of the forearm.¹⁸ Furthermore, in young patients, radiotherapy can increase the risk for developing nonmelanoma skin cancer later in life.¹⁶ 

Intralesional MTX is a localized treatment option that avoids the high costs of surgery, the side effects of radiotherapy, prolonged healing, and the systemic effects of chemotherapy. Treatment with IL-MTX can vary depending on the number of treatments necessary but usually only costs a few hundred dollars, rarely costing more than $1000.⁷ Although IL-MTX is less expensive, it typically requires several follow-up visits, whereas surgical removal may only require 1 visit.

Prior research has noted the efficacy of IL-MTX as a neoadjuvant therapy, with one study finding that IL-MTX can reduce the size of SCC lesions by an average of 0.52 cm² prior to surgery.¹⁹ Several case studies also have documented the effectiveness of IL-MTX as a treatment for SCC.^20-22 However, larger studies involving multiple patients to evaluate the efficacy of IL-MTX as a sole treatment for SCC are lacking. Gualdi et al²³ looked at the outcomes (complete resolution, partial response, or no response) for SCC treated with IL-MTX and found that 62% (13/21) of patients experienced improvement, with 48% (10/21) experiencing at least 50% improvement. Although these results are promising, further research is needed.

Our study sought to examine IL-MTX efficacy as well as evaluate the dosage and number of appointments/­sessions needed to achieve resolution of the lesions.

Methods

We conducted a retrospective chart review of patients who received only IL-MTX for clinically evident or biopsy-proven SCC at US Dermatology Partners clinics in Phoenix, Arizona, from January 1, 2022, to June 30, 2023. Patients aged 18 to 89 years were included, and they had not received other treatment for their SCC lesions such as radiation or systemic chemotherapy. Each patient received at least 1 dose of IL-MTX, beginning with a concentration of 12.5 mg/mL and with all subsequent doses at a concentration of 25 mg/mL (low dose vs high dose). Lesion resolution was categorized as no gross clinical tumor on follow-up. Patients received additional doses of IL-MTX based on the clinical appearance of their lesion(s).

Patient-level descriptive statistics are reported as mean (SD) or median (interquartile range [IQR]) for continuous variables as well as frequency and percentage for categorical variables. To account for the correlation of multiple lesions within individual patients, marginal Cox proportional hazard models were used. Time as well as cumulative dose to lesion resolution were evaluated and presented via the cumulative hazard function, while differences in resolution were estimated using separate Cox models for age, sex, and initial dose.

Results

In total, 107 different lesions from 21 patients were included in the analysis. The median number of lesions was 4 per patient (range, 1-15; IQR, 2-7), with a mean (SD) age of 80 (6) years. Patients were primarily female (81% [17/21]). From the data provided, the majority of lesions (83% [89/107]) resolved with IL-MTX. Of the 18 unresolved lesions, 5 (5%) were referred for a different procedure, and the remaining 13 (12%) were censored (lost to follow-up). Figure 1 provides the cumulative incidence function for lesion resolution. Approximately 50% of patient lesions resolved by the second appointment. Similarly, Figure 2 provides the cumulative dose function for lesion resolution; the median cumulative total dose for resolution was 5 mg (IQR, 2.5–12.5). Finally, concerning the ratio for case resolution, no difference in hazard ratio (HR) was observed for age (female vs male, HR: 1.01; 95% CI: 0.96-1.06), biological sex (HR, 1.01; 95% CI, 0.63-1.63), or initial dose (high vs low, HR: 1.13; 95% CI: 0.77-1.65).

Comment

Results of this study demonstrate the efficacy of IL-MTX for the treatment of cutaneous SCC. More than 80% of the lesions resolved by IL-MTX alone. This treatment approach is more cost-effective with fewer adverse effects when compared to other options. In our study, treatment with IL-MTX also proved to be reasonable in terms of the number of appointments and total dose required, with more than 50% of lesions resolving within 2 appointments and a median cumulative total dose of 5 mg. Intralesional MTX appears to be similarly efficacious in men and women, and the concentration of the initial dose (12.5 mg/mL vs 25 mg/mL) does not change the treatment outcome.

Although these data are encouraging for the use of IL-MTX in the treatment of SCC, future work should consider the relationships between lesion characteristics (such as size and location) and case resolution with IL-MTX as well as recurrence rates with lesions treated by IL-MTX compared to other treatment options.

Conclusion

This study demonstrated the efficacy of IL-MTX as a treatment for SCC that is cost-effective, avoids bothersome side effects, and can be accomplished in relatively few appointments. However, more data are needed to characterize the lesion type best suited to this treatment.

Squamous cell carcinoma (SCC) is the malignant proliferation of keratinocytes in the epidermis of the skin. Most SCCs are caused by UV light exposure, with sex and increased age acting as the primary known risk factors: SCCs are nearly twice as prevalent in men vs women, and the average age of presentation is the middle of the seventh decade of life.¹ In the United States, there are an estimated 1.8 million new SCC cases annually.² Although not usually life threatening, if left untreated, SCC can metastasize, thereby reducing the 10-year survival rate from above 90% with treatment to 16%.^3-6

Most invasive SCC lesions are treated surgically, but intralesional methotrexate (IL-MTX) has emerged as an alternative treatment for cutaneous SCC. It offers the potential for lower-cost, efficacious outpatient treatment.^7-12 Methotrexate competitively inhibits the enzyme dihydrofolate reductase, which converts dihydrofolate into tetrahydrofolate.¹³ In doing so, MTX indirectly prevents the synthesis of thymine, a nucleotide required for DNA synthesis. Thus, MTX can halt DNA synthesis and consequently, cell division. Intralesional MTX has been shown to successfully treat keratoacanthomas, lymphomas, and various inflammatory dermatologic conditions.^8-12 

Surgical options include standard excision, Mohs micrographic surgery, or electrodesiccation and curettage. Surgical treatment has high (92% to 99%) cure rates and typically requires only 1 or 2 appointments.^14,15 Although costs can vary, one 2012 study using Medicare fee schedules found that total costs (including primary procedure, biopsy, follow-up appointments through 2 months, and other associated costs) for cutaneous SCC were $475 for electrodesiccation and curettage, $1302.92 for excision, and $2093.14 for Mohs micrographic surgery.¹⁶ For some patients, surgery is not an ideal option due to the tumor location, poor wound healing, anticoagulation, and cost. In these patients, photodynamic therapy, topical therapy with 5-fluorouracil or imiquimod, radiation, and cryotherapy are options listed in the American Academy of Dermatology guidelines.¹⁵ Compared with surgery, radiation is more demanding on the patient, often requiring multiple visits a week and including common undesirable adverse effects such as radiation dermatitis and prolonged wounds on the lower legs.¹⁷ Radiation also can be costly, with one study reporting costs between $2559 and $3431 for SCC of the forearm.¹⁸ Furthermore, in young patients, radiotherapy can increase the risk for developing nonmelanoma skin cancer later in life.¹⁶ 

Intralesional MTX is a localized treatment option that avoids the high costs of surgery, the side effects of radiotherapy, prolonged healing, and the systemic effects of chemotherapy. Treatment with IL-MTX can vary depending on the number of treatments necessary but usually only costs a few hundred dollars, rarely costing more than $1000.⁷ Although IL-MTX is less expensive, it typically requires several follow-up visits, whereas surgical removal may only require 1 visit.

Prior research has noted the efficacy of IL-MTX as a neoadjuvant therapy, with one study finding that IL-MTX can reduce the size of SCC lesions by an average of 0.52 cm² prior to surgery.¹⁹ Several case studies also have documented the effectiveness of IL-MTX as a treatment for SCC.^20-22 However, larger studies involving multiple patients to evaluate the efficacy of IL-MTX as a sole treatment for SCC are lacking. Gualdi et al²³ looked at the outcomes (complete resolution, partial response, or no response) for SCC treated with IL-MTX and found that 62% (13/21) of patients experienced improvement, with 48% (10/21) experiencing at least 50% improvement. Although these results are promising, further research is needed.

Our study sought to examine IL-MTX efficacy as well as evaluate the dosage and number of appointments/­sessions needed to achieve resolution of the lesions.

Methods

We conducted a retrospective chart review of patients who received only IL-MTX for clinically evident or biopsy-proven SCC at US Dermatology Partners clinics in Phoenix, Arizona, from January 1, 2022, to June 30, 2023. Patients aged 18 to 89 years were included, and they had not received other treatment for their SCC lesions such as radiation or systemic chemotherapy. Each patient received at least 1 dose of IL-MTX, beginning with a concentration of 12.5 mg/mL and with all subsequent doses at a concentration of 25 mg/mL (low dose vs high dose). Lesion resolution was categorized as no gross clinical tumor on follow-up. Patients received additional doses of IL-MTX based on the clinical appearance of their lesion(s).

Patient-level descriptive statistics are reported as mean (SD) or median (interquartile range [IQR]) for continuous variables as well as frequency and percentage for categorical variables. To account for the correlation of multiple lesions within individual patients, marginal Cox proportional hazard models were used. Time as well as cumulative dose to lesion resolution were evaluated and presented via the cumulative hazard function, while differences in resolution were estimated using separate Cox models for age, sex, and initial dose.

Results

In total, 107 different lesions from 21 patients were included in the analysis. The median number of lesions was 4 per patient (range, 1-15; IQR, 2-7), with a mean (SD) age of 80 (6) years. Patients were primarily female (81% [17/21]). From the data provided, the majority of lesions (83% [89/107]) resolved with IL-MTX. Of the 18 unresolved lesions, 5 (5%) were referred for a different procedure, and the remaining 13 (12%) were censored (lost to follow-up). Figure 1 provides the cumulative incidence function for lesion resolution. Approximately 50% of patient lesions resolved by the second appointment. Similarly, Figure 2 provides the cumulative dose function for lesion resolution; the median cumulative total dose for resolution was 5 mg (IQR, 2.5–12.5). Finally, concerning the ratio for case resolution, no difference in hazard ratio (HR) was observed for age (female vs male, HR: 1.01; 95% CI: 0.96-1.06), biological sex (HR, 1.01; 95% CI, 0.63-1.63), or initial dose (high vs low, HR: 1.13; 95% CI: 0.77-1.65).

Comment

Results of this study demonstrate the efficacy of IL-MTX for the treatment of cutaneous SCC. More than 80% of the lesions resolved by IL-MTX alone. This treatment approach is more cost-effective with fewer adverse effects when compared to other options. In our study, treatment with IL-MTX also proved to be reasonable in terms of the number of appointments and total dose required, with more than 50% of lesions resolving within 2 appointments and a median cumulative total dose of 5 mg. Intralesional MTX appears to be similarly efficacious in men and women, and the concentration of the initial dose (12.5 mg/mL vs 25 mg/mL) does not change the treatment outcome.

Although these data are encouraging for the use of IL-MTX in the treatment of SCC, future work should consider the relationships between lesion characteristics (such as size and location) and case resolution with IL-MTX as well as recurrence rates with lesions treated by IL-MTX compared to other treatment options.

Conclusion

This study demonstrated the efficacy of IL-MTX as a treatment for SCC that is cost-effective, avoids bothersome side effects, and can be accomplished in relatively few appointments. However, more data are needed to characterize the lesion type best suited to this treatment.

Squamous cell carcinoma (SCC) is the malignant proliferation of keratinocytes in the epidermis of the skin. Most SCCs are caused by UV light exposure, with sex and increased age acting as the primary known risk factors: SCCs are nearly twice as prevalent in men vs women, and the average age of presentation is the middle of the seventh decade of life.¹ In the United States, there are an estimated 1.8 million new SCC cases annually.² Although not usually life threatening, if left untreated, SCC can metastasize, thereby reducing the 10-year survival rate from above 90% with treatment to 16%.^3-6

Most invasive SCC lesions are treated surgically, but intralesional methotrexate (IL-MTX) has emerged as an alternative treatment for cutaneous SCC. It offers the potential for lower-cost, efficacious outpatient treatment.^7-12 Methotrexate competitively inhibits the enzyme dihydrofolate reductase, which converts dihydrofolate into tetrahydrofolate.¹³ In doing so, MTX indirectly prevents the synthesis of thymine, a nucleotide required for DNA synthesis. Thus, MTX can halt DNA synthesis and consequently, cell division. Intralesional MTX has been shown to successfully treat keratoacanthomas, lymphomas, and various inflammatory dermatologic conditions.^8-12 

Surgical options include standard excision, Mohs micrographic surgery, or electrodesiccation and curettage. Surgical treatment has high (92% to 99%) cure rates and typically requires only 1 or 2 appointments.^14,15 Although costs can vary, one 2012 study using Medicare fee schedules found that total costs (including primary procedure, biopsy, follow-up appointments through 2 months, and other associated costs) for cutaneous SCC were $475 for electrodesiccation and curettage, $1302.92 for excision, and $2093.14 for Mohs micrographic surgery.¹⁶ For some patients, surgery is not an ideal option due to the tumor location, poor wound healing, anticoagulation, and cost. In these patients, photodynamic therapy, topical therapy with 5-fluorouracil or imiquimod, radiation, and cryotherapy are options listed in the American Academy of Dermatology guidelines.¹⁵ Compared with surgery, radiation is more demanding on the patient, often requiring multiple visits a week and including common undesirable adverse effects such as radiation dermatitis and prolonged wounds on the lower legs.¹⁷ Radiation also can be costly, with one study reporting costs between $2559 and $3431 for SCC of the forearm.¹⁸ Furthermore, in young patients, radiotherapy can increase the risk for developing nonmelanoma skin cancer later in life.¹⁶ 

Intralesional MTX is a localized treatment option that avoids the high costs of surgery, the side effects of radiotherapy, prolonged healing, and the systemic effects of chemotherapy. Treatment with IL-MTX can vary depending on the number of treatments necessary but usually only costs a few hundred dollars, rarely costing more than $1000.⁷ Although IL-MTX is less expensive, it typically requires several follow-up visits, whereas surgical removal may only require 1 visit.

Prior research has noted the efficacy of IL-MTX as a neoadjuvant therapy, with one study finding that IL-MTX can reduce the size of SCC lesions by an average of 0.52 cm² prior to surgery.¹⁹ Several case studies also have documented the effectiveness of IL-MTX as a treatment for SCC.^20-22 However, larger studies involving multiple patients to evaluate the efficacy of IL-MTX as a sole treatment for SCC are lacking. Gualdi et al²³ looked at the outcomes (complete resolution, partial response, or no response) for SCC treated with IL-MTX and found that 62% (13/21) of patients experienced improvement, with 48% (10/21) experiencing at least 50% improvement. Although these results are promising, further research is needed.

Our study sought to examine IL-MTX efficacy as well as evaluate the dosage and number of appointments/­sessions needed to achieve resolution of the lesions.

Methods

We conducted a retrospective chart review of patients who received only IL-MTX for clinically evident or biopsy-proven SCC at US Dermatology Partners clinics in Phoenix, Arizona, from January 1, 2022, to June 30, 2023. Patients aged 18 to 89 years were included, and they had not received other treatment for their SCC lesions such as radiation or systemic chemotherapy. Each patient received at least 1 dose of IL-MTX, beginning with a concentration of 12.5 mg/mL and with all subsequent doses at a concentration of 25 mg/mL (low dose vs high dose). Lesion resolution was categorized as no gross clinical tumor on follow-up. Patients received additional doses of IL-MTX based on the clinical appearance of their lesion(s).

Patient-level descriptive statistics are reported as mean (SD) or median (interquartile range [IQR]) for continuous variables as well as frequency and percentage for categorical variables. To account for the correlation of multiple lesions within individual patients, marginal Cox proportional hazard models were used. Time as well as cumulative dose to lesion resolution were evaluated and presented via the cumulative hazard function, while differences in resolution were estimated using separate Cox models for age, sex, and initial dose.

Results

In total, 107 different lesions from 21 patients were included in the analysis. The median number of lesions was 4 per patient (range, 1-15; IQR, 2-7), with a mean (SD) age of 80 (6) years. Patients were primarily female (81% [17/21]). From the data provided, the majority of lesions (83% [89/107]) resolved with IL-MTX. Of the 18 unresolved lesions, 5 (5%) were referred for a different procedure, and the remaining 13 (12%) were censored (lost to follow-up). Figure 1 provides the cumulative incidence function for lesion resolution. Approximately 50% of patient lesions resolved by the second appointment. Similarly, Figure 2 provides the cumulative dose function for lesion resolution; the median cumulative total dose for resolution was 5 mg (IQR, 2.5–12.5). Finally, concerning the ratio for case resolution, no difference in hazard ratio (HR) was observed for age (female vs male, HR: 1.01; 95% CI: 0.96-1.06), biological sex (HR, 1.01; 95% CI, 0.63-1.63), or initial dose (high vs low, HR: 1.13; 95% CI: 0.77-1.65).

Comment

Results of this study demonstrate the efficacy of IL-MTX for the treatment of cutaneous SCC. More than 80% of the lesions resolved by IL-MTX alone. This treatment approach is more cost-effective with fewer adverse effects when compared to other options. In our study, treatment with IL-MTX also proved to be reasonable in terms of the number of appointments and total dose required, with more than 50% of lesions resolving within 2 appointments and a median cumulative total dose of 5 mg. Intralesional MTX appears to be similarly efficacious in men and women, and the concentration of the initial dose (12.5 mg/mL vs 25 mg/mL) does not change the treatment outcome.

Although these data are encouraging for the use of IL-MTX in the treatment of SCC, future work should consider the relationships between lesion characteristics (such as size and location) and case resolution with IL-MTX as well as recurrence rates with lesions treated by IL-MTX compared to other treatment options.

Conclusion

This study demonstrated the efficacy of IL-MTX as a treatment for SCC that is cost-effective, avoids bothersome side effects, and can be accomplished in relatively few appointments. However, more data are needed to characterize the lesion type best suited to this treatment.

When Skin Cancer Awareness Month rolls around every May, my social media feed is inundated with posts extolling the benefits of total body skin examinations and the life-saving potential of skin cancer screenings; however, time and again the US Preventive Services Task Force (USPSTF)—the leading authority on evidence-based public health recommendations in the United States—has found the evidence supporting skin cancer screenings to be insufficient. The USPSTF has cited a lack of high-quality studies and inadequate data to recommend screening for the general population, excluding those at elevated risk due to personal, family, or occupational history.¹ A 2019 Cochrane review went further, concluding that current evidence refutes the utility of population-based screening for melanoma.²

Despite these findings, skin cancer screenings and total body skin examinations remain popular among patients both with and without a personal or family history of cutaneous malignancy. Indeed, the anecdotal experience of dermatologists worldwide suggests an intangible benefit to screening that persists, even if robust data to support it remain elusive.

Putting aside studies that suggest these screenings help identify melanomas at earlier stages and with reduced Breslow thicknesses,³ there is a crucial benefit from face-to-face interaction between medical professionals and the public during skin cancer screening events or health fairs. This interaction has become especially important in an era when misinformation thrives online and so-called skin care “experts” with no formal training can amass tens of thousands—or even millions—of followers on social media.

So, what are the intangible benefits of the face-to-face interactions that occur naturally during skin cancer screenings? The most obvious is education. While the USPSTF may not recommend routine screening for skin cancer in the general population, it does endorse education for children, adolescents, and adults on the importance of minimizing exposure to UV radiation, particularly those with lighter skin tones.⁴ Publicly advertised skin cancer screenings at health fairs or other community events may offer an opportunity to raise awareness about sun safety and protection, including the value of peak UV avoidance, sun-protective clothing, and proper sunscreen use; these settings also serve as platforms for health care providers to counter misinformation, including concerns about sunscreen safety both for the patient and the environment, overhyped risks for vitamin D deficiency from sun avoidance, and myths about low skin cancer risk in patients with skin of color.

While the benefits of skin self-examination (SSE) remain uncertain, especially in low-risk populations, screening events provide an opportunity to educate patients on who is most likely to benefit from SSE and in whom the practice may cause more harm than good.⁵ For higher-risk individuals such as melanoma survivors or those with a strong family history, screening fairs can serve as meaningful touchpoints that reinforce the importance of sun protection and regular examinations with a health care provider. For those eager to perform SSEs, these events offer the chance to teach best ­practices—how to conduct SSEs effectively, what features to look for (eg, the ABCDE method or the ugly duckling sign), and when to seek professional care.

Finally (and importantly), skin cancer screening events provide peace of mind for patients. Reassurance from a professional about a benign skin lesion can alleviate anxiety that might otherwise lead to emergency or urgent care visits. While cellulitis and other skin infections are the most common dermatologic conditions seen in emergency settings, benign neoplasms and similar nonurgent conditions still contribute a substantial burden to urgent care systems in the United States.⁶ Outside emergency care, systems-level data support what many of us observe in practice: two of the most common reasons for referral to dermatology are benign neoplasms and epidermoid cysts, accounting for millions of visits annually.⁷ In fact, recent claims data suggest that the most common diagnosis made in US dermatology clinics in 2023 was (you guessed it!) seborrheic keratosis.⁸

What if instead of requiring a patient to wait weeks for a primary care appointment and months for a dermatology referral—all while worrying about a rapidly growing pigmented lesion and incurring costs in copays, travel, lost wages, and time away from work—we offered a fast, trustworthy, and free evaluation that meets the patient where they live, work, or socialize? An evaluation that not only eases their fears but also provides meaningful education about skin cancer prevention and screening guidelines? While precautions must of course be taken to ensure that the quality and completeness of such an examination equals that of an in-clinic evaluation, if services of this quality can be provided, public screening events may offer a simple, accessible, and valuable solution that delivers peace of mind and helps reduce unnecessary strain on emergency, primary, and specialty care networks.

When Skin Cancer Awareness Month rolls around every May, my social media feed is inundated with posts extolling the benefits of total body skin examinations and the life-saving potential of skin cancer screenings; however, time and again the US Preventive Services Task Force (USPSTF)—the leading authority on evidence-based public health recommendations in the United States—has found the evidence supporting skin cancer screenings to be insufficient. The USPSTF has cited a lack of high-quality studies and inadequate data to recommend screening for the general population, excluding those at elevated risk due to personal, family, or occupational history.¹ A 2019 Cochrane review went further, concluding that current evidence refutes the utility of population-based screening for melanoma.²

Despite these findings, skin cancer screenings and total body skin examinations remain popular among patients both with and without a personal or family history of cutaneous malignancy. Indeed, the anecdotal experience of dermatologists worldwide suggests an intangible benefit to screening that persists, even if robust data to support it remain elusive.

Putting aside studies that suggest these screenings help identify melanomas at earlier stages and with reduced Breslow thicknesses,³ there is a crucial benefit from face-to-face interaction between medical professionals and the public during skin cancer screening events or health fairs. This interaction has become especially important in an era when misinformation thrives online and so-called skin care “experts” with no formal training can amass tens of thousands—or even millions—of followers on social media.

So, what are the intangible benefits of the face-to-face interactions that occur naturally during skin cancer screenings? The most obvious is education. While the USPSTF may not recommend routine screening for skin cancer in the general population, it does endorse education for children, adolescents, and adults on the importance of minimizing exposure to UV radiation, particularly those with lighter skin tones.⁴ Publicly advertised skin cancer screenings at health fairs or other community events may offer an opportunity to raise awareness about sun safety and protection, including the value of peak UV avoidance, sun-protective clothing, and proper sunscreen use; these settings also serve as platforms for health care providers to counter misinformation, including concerns about sunscreen safety both for the patient and the environment, overhyped risks for vitamin D deficiency from sun avoidance, and myths about low skin cancer risk in patients with skin of color.

While the benefits of skin self-examination (SSE) remain uncertain, especially in low-risk populations, screening events provide an opportunity to educate patients on who is most likely to benefit from SSE and in whom the practice may cause more harm than good.⁵ For higher-risk individuals such as melanoma survivors or those with a strong family history, screening fairs can serve as meaningful touchpoints that reinforce the importance of sun protection and regular examinations with a health care provider. For those eager to perform SSEs, these events offer the chance to teach best ­practices—how to conduct SSEs effectively, what features to look for (eg, the ABCDE method or the ugly duckling sign), and when to seek professional care.

Finally (and importantly), skin cancer screening events provide peace of mind for patients. Reassurance from a professional about a benign skin lesion can alleviate anxiety that might otherwise lead to emergency or urgent care visits. While cellulitis and other skin infections are the most common dermatologic conditions seen in emergency settings, benign neoplasms and similar nonurgent conditions still contribute a substantial burden to urgent care systems in the United States.⁶ Outside emergency care, systems-level data support what many of us observe in practice: two of the most common reasons for referral to dermatology are benign neoplasms and epidermoid cysts, accounting for millions of visits annually.⁷ In fact, recent claims data suggest that the most common diagnosis made in US dermatology clinics in 2023 was (you guessed it!) seborrheic keratosis.⁸

What if instead of requiring a patient to wait weeks for a primary care appointment and months for a dermatology referral—all while worrying about a rapidly growing pigmented lesion and incurring costs in copays, travel, lost wages, and time away from work—we offered a fast, trustworthy, and free evaluation that meets the patient where they live, work, or socialize? An evaluation that not only eases their fears but also provides meaningful education about skin cancer prevention and screening guidelines? While precautions must of course be taken to ensure that the quality and completeness of such an examination equals that of an in-clinic evaluation, if services of this quality can be provided, public screening events may offer a simple, accessible, and valuable solution that delivers peace of mind and helps reduce unnecessary strain on emergency, primary, and specialty care networks.

When Skin Cancer Awareness Month rolls around every May, my social media feed is inundated with posts extolling the benefits of total body skin examinations and the life-saving potential of skin cancer screenings; however, time and again the US Preventive Services Task Force (USPSTF)—the leading authority on evidence-based public health recommendations in the United States—has found the evidence supporting skin cancer screenings to be insufficient. The USPSTF has cited a lack of high-quality studies and inadequate data to recommend screening for the general population, excluding those at elevated risk due to personal, family, or occupational history.¹ A 2019 Cochrane review went further, concluding that current evidence refutes the utility of population-based screening for melanoma.²

Despite these findings, skin cancer screenings and total body skin examinations remain popular among patients both with and without a personal or family history of cutaneous malignancy. Indeed, the anecdotal experience of dermatologists worldwide suggests an intangible benefit to screening that persists, even if robust data to support it remain elusive.

Putting aside studies that suggest these screenings help identify melanomas at earlier stages and with reduced Breslow thicknesses,³ there is a crucial benefit from face-to-face interaction between medical professionals and the public during skin cancer screening events or health fairs. This interaction has become especially important in an era when misinformation thrives online and so-called skin care “experts” with no formal training can amass tens of thousands—or even millions—of followers on social media.

So, what are the intangible benefits of the face-to-face interactions that occur naturally during skin cancer screenings? The most obvious is education. While the USPSTF may not recommend routine screening for skin cancer in the general population, it does endorse education for children, adolescents, and adults on the importance of minimizing exposure to UV radiation, particularly those with lighter skin tones.⁴ Publicly advertised skin cancer screenings at health fairs or other community events may offer an opportunity to raise awareness about sun safety and protection, including the value of peak UV avoidance, sun-protective clothing, and proper sunscreen use; these settings also serve as platforms for health care providers to counter misinformation, including concerns about sunscreen safety both for the patient and the environment, overhyped risks for vitamin D deficiency from sun avoidance, and myths about low skin cancer risk in patients with skin of color.

While the benefits of skin self-examination (SSE) remain uncertain, especially in low-risk populations, screening events provide an opportunity to educate patients on who is most likely to benefit from SSE and in whom the practice may cause more harm than good.⁵ For higher-risk individuals such as melanoma survivors or those with a strong family history, screening fairs can serve as meaningful touchpoints that reinforce the importance of sun protection and regular examinations with a health care provider. For those eager to perform SSEs, these events offer the chance to teach best ­practices—how to conduct SSEs effectively, what features to look for (eg, the ABCDE method or the ugly duckling sign), and when to seek professional care.

Finally (and importantly), skin cancer screening events provide peace of mind for patients. Reassurance from a professional about a benign skin lesion can alleviate anxiety that might otherwise lead to emergency or urgent care visits. While cellulitis and other skin infections are the most common dermatologic conditions seen in emergency settings, benign neoplasms and similar nonurgent conditions still contribute a substantial burden to urgent care systems in the United States.⁶ Outside emergency care, systems-level data support what many of us observe in practice: two of the most common reasons for referral to dermatology are benign neoplasms and epidermoid cysts, accounting for millions of visits annually.⁷ In fact, recent claims data suggest that the most common diagnosis made in US dermatology clinics in 2023 was (you guessed it!) seborrheic keratosis.⁸

What if instead of requiring a patient to wait weeks for a primary care appointment and months for a dermatology referral—all while worrying about a rapidly growing pigmented lesion and incurring costs in copays, travel, lost wages, and time away from work—we offered a fast, trustworthy, and free evaluation that meets the patient where they live, work, or socialize? An evaluation that not only eases their fears but also provides meaningful education about skin cancer prevention and screening guidelines? While precautions must of course be taken to ensure that the quality and completeness of such an examination equals that of an in-clinic evaluation, if services of this quality can be provided, public screening events may offer a simple, accessible, and valuable solution that delivers peace of mind and helps reduce unnecessary strain on emergency, primary, and specialty care networks.

Practice Gap

Tissue processing and complete margin assessment in Mohs micrographic surgery (MMS) are challenging concepts for residents, yet they are essential components of the dermatology residency curriculum. We propose a hands-on active teaching method using craft foam blocks to help residents master these techniques. Prior educational tools have included instructional videos¹ as well as the peanut butter–cup and cantaloupe analogies.^2,3 Specifically, our method utilizes inexpensive, readily available supplies that allow for repeated practice in a low-stakes environment without limitation of resources. This method provides an immersive, hands-on experience that allows residents to perform multiple practice excisions and simulate positive peripheral or deep margins, unlike tools that offer only fixed-depth or purely visual representations. Additionally, our learning model uniquely enables residents to flatten the simulated tissue, providing a clearer understanding of how a 3-dimensional specimen is transformed on a slide during histologic preparation. This step is particularly important, as tissue architecture can shift during processing, making it one of the most difficult concepts to grasp without hands-on experience. Having a multitude of teaching methods is crucial to accommodate various learning styles, and active learning has been shown to enhance retention for dermatology residents.⁴

The Technique

Residents use simple art supplies (including craft foam blocks and ink) and inexpensive, readily available surgical tools to simulate MMS (Table)(Figure 1). If desired, the resident can follow along with the comprehensive, stepwise textbook description of MMS, outlined by Benedetto et al⁵ to contextualize this hands-on exercise within a standardized didactic framework.

The foam block, which represents patient tissue, serves as the specimen. The resident begins by freehand drawing a simulated cutaneous tumor directly onto the foam using a surgical marking pen. At this point, the instructor discusses the advantages and limitations of tumor debulking with a sharp blade or curette. Residents then mark appropriate margins (1-3 mm) of normal-appearing “epidermis” on the foam block and add hash marks for orientation. This is another opportunity for the instructor to discuss common methods for marking tissue in vivo and to review situations when larger or smaller margins might be appropriate. 

Next, the resident removes the first layer of simulated tissue using a disposable #15 blade scalpel at a 45° angle circumferentially and deep around the representative tumor. The resident also may use scissors and tissue forceps to remove the representative tumor. Next, the excised foam layer (the simulated “specimen”) is transferred to gauze. To demonstrate a positive margin, the resident or instructor marks the deep or peripheral foam block with a surgical marking pen, indicating residual tumor (Figure 2). This allows for multiple sequential layers of foam to be removed, demonstrating successive stages of MMS. 

An inkwell holds different colors of washable paint to simulate tissue inking. After excision, the resident uses cotton-tipped applicators to apply different paint colors to the edges of the excised foam specimen at designated orientation points (eg, 3 o'clock and 12 o'clock). The resident then records the location of the excised sample by hand-drawing it on a printable Mohs map, labeling the corresponding paint colors to indicate orientation (Figure 3). 

The resident then places the specimen between 2 ­plastic page protectors mimicking a glass slide and cover slip. Clear tape can be used to help flatten the specimen (Figure 4). The tissue is compressed between the page protector so that the simulated epidermis, dermis, and subcutaneous fat are all in the same plane. At this stage, the instructor may discuss the use of relaxing incisions, especially for deeper tissue specimens or when excision at a 45° bevel is not achieved.⁵ The view from the underside of the page protector reveals 100% of the specimen’s margin and mimics the first cut off the tissue block. The resident can visualize the complete circumferential, peripheral, and deep margins and can easily identify any positive margins. At this point, the exercise can conclude, or the resident can explore further stages for positive margins, bisected specimens, or other tissue preparation variations.

Practice Implications

By individually designing and removing a representative tumor with margins, creating hash marks, and preparing a tissue specimen for histologic analysis, our interactive teaching method provides dermatology residents with a relatively simple, effective, and active learning experience for MMS outside the surgical setting. Using a piece of craft foam allows the representative tissue to be manipulated and flattened, similar to cutaneous tissue. This method was implemented and refined across 3 separate teaching sessions held by teaching faculty (E.I.P and E.B.W.) at the San Antonio Uniformed Services Health Education Consortium Dermatology Residency Program (San Antonio, Texas). This method has consistently generated strong resident engagement and prompted insightful questions and discussions. Program directors at other residency programs can readily incorporate this method in their surgical curriculum by allocating a brief didactic period to the exercise and facilitating the discussion with a dermatologic surgeon. Its simplicity, low cost, and effectiveness make the foam block model an easily adoptable teaching tool for dermatology residency programs seeking to provide a comprehensive, hands-on understanding of MMS.

Practice Gap

Tissue processing and complete margin assessment in Mohs micrographic surgery (MMS) are challenging concepts for residents, yet they are essential components of the dermatology residency curriculum. We propose a hands-on active teaching method using craft foam blocks to help residents master these techniques. Prior educational tools have included instructional videos¹ as well as the peanut butter–cup and cantaloupe analogies.^2,3 Specifically, our method utilizes inexpensive, readily available supplies that allow for repeated practice in a low-stakes environment without limitation of resources. This method provides an immersive, hands-on experience that allows residents to perform multiple practice excisions and simulate positive peripheral or deep margins, unlike tools that offer only fixed-depth or purely visual representations. Additionally, our learning model uniquely enables residents to flatten the simulated tissue, providing a clearer understanding of how a 3-dimensional specimen is transformed on a slide during histologic preparation. This step is particularly important, as tissue architecture can shift during processing, making it one of the most difficult concepts to grasp without hands-on experience. Having a multitude of teaching methods is crucial to accommodate various learning styles, and active learning has been shown to enhance retention for dermatology residents.⁴

The Technique

Residents use simple art supplies (including craft foam blocks and ink) and inexpensive, readily available surgical tools to simulate MMS (Table)(Figure 1). If desired, the resident can follow along with the comprehensive, stepwise textbook description of MMS, outlined by Benedetto et al⁵ to contextualize this hands-on exercise within a standardized didactic framework.

The foam block, which represents patient tissue, serves as the specimen. The resident begins by freehand drawing a simulated cutaneous tumor directly onto the foam using a surgical marking pen. At this point, the instructor discusses the advantages and limitations of tumor debulking with a sharp blade or curette. Residents then mark appropriate margins (1-3 mm) of normal-appearing “epidermis” on the foam block and add hash marks for orientation. This is another opportunity for the instructor to discuss common methods for marking tissue in vivo and to review situations when larger or smaller margins might be appropriate. 

Next, the resident removes the first layer of simulated tissue using a disposable #15 blade scalpel at a 45° angle circumferentially and deep around the representative tumor. The resident also may use scissors and tissue forceps to remove the representative tumor. Next, the excised foam layer (the simulated “specimen”) is transferred to gauze. To demonstrate a positive margin, the resident or instructor marks the deep or peripheral foam block with a surgical marking pen, indicating residual tumor (Figure 2). This allows for multiple sequential layers of foam to be removed, demonstrating successive stages of MMS. 

An inkwell holds different colors of washable paint to simulate tissue inking. After excision, the resident uses cotton-tipped applicators to apply different paint colors to the edges of the excised foam specimen at designated orientation points (eg, 3 o'clock and 12 o'clock). The resident then records the location of the excised sample by hand-drawing it on a printable Mohs map, labeling the corresponding paint colors to indicate orientation (Figure 3). 

The resident then places the specimen between 2 ­plastic page protectors mimicking a glass slide and cover slip. Clear tape can be used to help flatten the specimen (Figure 4). The tissue is compressed between the page protector so that the simulated epidermis, dermis, and subcutaneous fat are all in the same plane. At this stage, the instructor may discuss the use of relaxing incisions, especially for deeper tissue specimens or when excision at a 45° bevel is not achieved.⁵ The view from the underside of the page protector reveals 100% of the specimen’s margin and mimics the first cut off the tissue block. The resident can visualize the complete circumferential, peripheral, and deep margins and can easily identify any positive margins. At this point, the exercise can conclude, or the resident can explore further stages for positive margins, bisected specimens, or other tissue preparation variations.

Practice Implications

By individually designing and removing a representative tumor with margins, creating hash marks, and preparing a tissue specimen for histologic analysis, our interactive teaching method provides dermatology residents with a relatively simple, effective, and active learning experience for MMS outside the surgical setting. Using a piece of craft foam allows the representative tissue to be manipulated and flattened, similar to cutaneous tissue. This method was implemented and refined across 3 separate teaching sessions held by teaching faculty (E.I.P and E.B.W.) at the San Antonio Uniformed Services Health Education Consortium Dermatology Residency Program (San Antonio, Texas). This method has consistently generated strong resident engagement and prompted insightful questions and discussions. Program directors at other residency programs can readily incorporate this method in their surgical curriculum by allocating a brief didactic period to the exercise and facilitating the discussion with a dermatologic surgeon. Its simplicity, low cost, and effectiveness make the foam block model an easily adoptable teaching tool for dermatology residency programs seeking to provide a comprehensive, hands-on understanding of MMS.

Practice Gap

Tissue processing and complete margin assessment in Mohs micrographic surgery (MMS) are challenging concepts for residents, yet they are essential components of the dermatology residency curriculum. We propose a hands-on active teaching method using craft foam blocks to help residents master these techniques. Prior educational tools have included instructional videos¹ as well as the peanut butter–cup and cantaloupe analogies.^2,3 Specifically, our method utilizes inexpensive, readily available supplies that allow for repeated practice in a low-stakes environment without limitation of resources. This method provides an immersive, hands-on experience that allows residents to perform multiple practice excisions and simulate positive peripheral or deep margins, unlike tools that offer only fixed-depth or purely visual representations. Additionally, our learning model uniquely enables residents to flatten the simulated tissue, providing a clearer understanding of how a 3-dimensional specimen is transformed on a slide during histologic preparation. This step is particularly important, as tissue architecture can shift during processing, making it one of the most difficult concepts to grasp without hands-on experience. Having a multitude of teaching methods is crucial to accommodate various learning styles, and active learning has been shown to enhance retention for dermatology residents.⁴

The Technique

Residents use simple art supplies (including craft foam blocks and ink) and inexpensive, readily available surgical tools to simulate MMS (Table)(Figure 1). If desired, the resident can follow along with the comprehensive, stepwise textbook description of MMS, outlined by Benedetto et al⁵ to contextualize this hands-on exercise within a standardized didactic framework.

The foam block, which represents patient tissue, serves as the specimen. The resident begins by freehand drawing a simulated cutaneous tumor directly onto the foam using a surgical marking pen. At this point, the instructor discusses the advantages and limitations of tumor debulking with a sharp blade or curette. Residents then mark appropriate margins (1-3 mm) of normal-appearing “epidermis” on the foam block and add hash marks for orientation. This is another opportunity for the instructor to discuss common methods for marking tissue in vivo and to review situations when larger or smaller margins might be appropriate. 

Next, the resident removes the first layer of simulated tissue using a disposable #15 blade scalpel at a 45° angle circumferentially and deep around the representative tumor. The resident also may use scissors and tissue forceps to remove the representative tumor. Next, the excised foam layer (the simulated “specimen”) is transferred to gauze. To demonstrate a positive margin, the resident or instructor marks the deep or peripheral foam block with a surgical marking pen, indicating residual tumor (Figure 2). This allows for multiple sequential layers of foam to be removed, demonstrating successive stages of MMS. 

An inkwell holds different colors of washable paint to simulate tissue inking. After excision, the resident uses cotton-tipped applicators to apply different paint colors to the edges of the excised foam specimen at designated orientation points (eg, 3 o'clock and 12 o'clock). The resident then records the location of the excised sample by hand-drawing it on a printable Mohs map, labeling the corresponding paint colors to indicate orientation (Figure 3). 

The resident then places the specimen between 2 ­plastic page protectors mimicking a glass slide and cover slip. Clear tape can be used to help flatten the specimen (Figure 4). The tissue is compressed between the page protector so that the simulated epidermis, dermis, and subcutaneous fat are all in the same plane. At this stage, the instructor may discuss the use of relaxing incisions, especially for deeper tissue specimens or when excision at a 45° bevel is not achieved.⁵ The view from the underside of the page protector reveals 100% of the specimen’s margin and mimics the first cut off the tissue block. The resident can visualize the complete circumferential, peripheral, and deep margins and can easily identify any positive margins. At this point, the exercise can conclude, or the resident can explore further stages for positive margins, bisected specimens, or other tissue preparation variations.

Practice Implications

By individually designing and removing a representative tumor with margins, creating hash marks, and preparing a tissue specimen for histologic analysis, our interactive teaching method provides dermatology residents with a relatively simple, effective, and active learning experience for MMS outside the surgical setting. Using a piece of craft foam allows the representative tissue to be manipulated and flattened, similar to cutaneous tissue. This method was implemented and refined across 3 separate teaching sessions held by teaching faculty (E.I.P and E.B.W.) at the San Antonio Uniformed Services Health Education Consortium Dermatology Residency Program (San Antonio, Texas). This method has consistently generated strong resident engagement and prompted insightful questions and discussions. Program directors at other residency programs can readily incorporate this method in their surgical curriculum by allocating a brief didactic period to the exercise and facilitating the discussion with a dermatologic surgeon. Its simplicity, low cost, and effectiveness make the foam block model an easily adoptable teaching tool for dermatology residency programs seeking to provide a comprehensive, hands-on understanding of MMS.

Practice Gap

Tattoos have become increasingly prevalent in Western culture, with approximately 1 in 4 Americans having at least 1 tattoo. Individuals invest money, time, and even pain in getting tattoos, many of which hold special personal, family, or religious significance.¹ Various cutaneous pathologies may arise in areas of the skin with tattoos, including malignancies and inflammatory reactions to tattoo pigment, and in these cases, surgical management may be indicated.^2,3

Nonmelanoma skin cancers (NMSCs) such as superficial basal cell carcinomas on broadly sun-damaged areas (eg, trunk, torso), squamous cell carcinomas, reactive keratoacanthomas, and reactive pseudoepitheliomatous squamous hyperplasia diagnosed as squamous cell carcinoma have been reported to occur in or near areas of the skin with tattoos.² Mohs micrographic surgery (MMS) is the standard of care for removing NMSCs, particularly when they manifest in cosmetically sensitive areas.⁴ This treatment option allows for careful guided resection of tumors to minimize the risk for recurrence; it also preserves healthy tissue, which typically results in a smaller radial defect after the procedure is complete. 

Chronic reactions to tattoo pigment may include granulomatous tattoo reactions and pseudolymphomas.³ Treatment options may include immunosuppressives such as intralesional triamcinolone as well as pigment destruction via lasers⁵; however, not all tattoos are responsive to these treatments. Surgical excision is an effective and definitive treatment in this context, as tattoo pigment resides in or above the mid dermis to a depth of approximately 400 μm. Intradermal excision effectively removes the antigenic pigment.⁵

In these clinical scenarios, patients may be hesitant to pursue surgical treatment due to concerns that it may alter tattoo appearance. Many clinicians and surgeons may consider definitive treatment and tattoo preservation to be mutually exclusive, but this is not always the case. We propose a technique that utilizes conservative thickness layers (CTL) to minimize disruption to the appearance of tattoos in MMS for treatment of cutaneous malignancies as well as intradermal excision of tattoo pigment in the setting of chronic inflammatory tattoo reactions.

The Technique

In the appropriate clinical context, CTL can effectively result in defects that heal well by secondary intention and minimize collateral tissue distortion.⁴ Lesions manifesting in or near tattooed skin often are responsive to treatment with CTL; furthermore, CTL may preserve some deeper tattoo pigment, resulting in only partial loss of the tattooed skin.

Conservative thickness layers are performed intradermally, similar to removing traditional layers in MMS. For treatment of NMSCs, a margin is scored around the lesion, and then the blade is passed carefully under the lesion nearly parallel to the skin through an intradermal plane. It is important to avoid entering the subcuticular fat (Figure 1). The tissue then is processed normally in the Mohs laboratory for complete circumferential margin evaluation. If necessary and possible, subsequent layers also can be performed in the intradermal plane. Once total circumferential margin control is obtained, the wound is allowed to granulate and heal by secondary intention. As these processes occur, we have found that wound contraction is less likely with the dermis intact, resulting in less impact on the overall appearance of the tattoo (Figures 1 and 2). For very thin lesions, resultant defects may retain some residual tattoo pigment. The residual scars also may be responsive to tattoo revision, although a period of monitoring for recurrence should be considered if there is concern that revising the tattoo could obscure early recurrent tumors. From our experience, utilizing CTL for NMSCs that arise within or near tattoos results in favorable preservation of the tattoo appearance and high patient satisfaction.

The procedure is performed similarly for removal of allergenic tattoo pigment, with careful excision to the mid dermis. Since the areas affected by the cutaneous reaction may be relatively large, surgical precision is required to maintain a uniform depth to remove the tattoo pigment and preserve the deep dermis (Figure 2). Once removed, the defect can be left to granulate and heal by secondary intention. If the patient wants to have the tattoo revised in the future, it would be prudent to utilize pigment that the patient has responded favorably to. In our experience, this approach is effective and yields high patient satisfaction and minimizes morbidity.

Practice Implications

Tattoos often hold special meaning for patients; therefore, treatment of pathologies arising in or near tattooed skin should emphasize maintaining the appearance of the tattoo while still being effective. Conservative thickness layers in MMS and intradermal excisions for allergic reactions to tattoo pigment are an effective treatment strategy that clinicians may consider.

One shortcoming of using CTL for MMS is the need for subsequent layers to clear the tumor; however, data suggest that first-stage cure rates are extremely high even with CTL for appropriately selected patients, with clearance of nearly 80% of tumors on the first stage. Tumors that may be most responsive to CTL include exophytic NMSCs and those arising in areas with a thicker dermis, including the back, legs, and scalp, although other locations including the face, hands, shins, ankles, and feet also may be well suited for CTL.⁴ Another shortcoming of CTL is that skin cancers arising in tattoos may not be considered appropriate for MMS based on the 2012 Appropriate Use Criteria, which consider factors such as location, type of cancer, size of the lesion, and patient characteristics to determine whether a skin cancer is appropriate for treatment with MMS.⁶ When the Appropriate Use Criteria categorizes a cancer as uncertain or inappropriate for MMS, the clinician must use their clinical judgment to determine whether MMS is the preferred treatment approach.⁷ Given the cosmetic significance of tattoos, location of a skin cancer near a tattoo could be taken into account for skin cancers that might otherwise not meet Appropriate Use Criteria. 

Conservative thickness layers in MMS and intradermal excisions of tattoo pigment are both effective techniques of minimizing disruption of tattoos while effectively treating patients.

Practice Gap

Tattoos have become increasingly prevalent in Western culture, with approximately 1 in 4 Americans having at least 1 tattoo. Individuals invest money, time, and even pain in getting tattoos, many of which hold special personal, family, or religious significance.¹ Various cutaneous pathologies may arise in areas of the skin with tattoos, including malignancies and inflammatory reactions to tattoo pigment, and in these cases, surgical management may be indicated.^2,3

Nonmelanoma skin cancers (NMSCs) such as superficial basal cell carcinomas on broadly sun-damaged areas (eg, trunk, torso), squamous cell carcinomas, reactive keratoacanthomas, and reactive pseudoepitheliomatous squamous hyperplasia diagnosed as squamous cell carcinoma have been reported to occur in or near areas of the skin with tattoos.² Mohs micrographic surgery (MMS) is the standard of care for removing NMSCs, particularly when they manifest in cosmetically sensitive areas.⁴ This treatment option allows for careful guided resection of tumors to minimize the risk for recurrence; it also preserves healthy tissue, which typically results in a smaller radial defect after the procedure is complete. 

Chronic reactions to tattoo pigment may include granulomatous tattoo reactions and pseudolymphomas.³ Treatment options may include immunosuppressives such as intralesional triamcinolone as well as pigment destruction via lasers⁵; however, not all tattoos are responsive to these treatments. Surgical excision is an effective and definitive treatment in this context, as tattoo pigment resides in or above the mid dermis to a depth of approximately 400 μm. Intradermal excision effectively removes the antigenic pigment.⁵

In these clinical scenarios, patients may be hesitant to pursue surgical treatment due to concerns that it may alter tattoo appearance. Many clinicians and surgeons may consider definitive treatment and tattoo preservation to be mutually exclusive, but this is not always the case. We propose a technique that utilizes conservative thickness layers (CTL) to minimize disruption to the appearance of tattoos in MMS for treatment of cutaneous malignancies as well as intradermal excision of tattoo pigment in the setting of chronic inflammatory tattoo reactions.

The Technique

In the appropriate clinical context, CTL can effectively result in defects that heal well by secondary intention and minimize collateral tissue distortion.⁴ Lesions manifesting in or near tattooed skin often are responsive to treatment with CTL; furthermore, CTL may preserve some deeper tattoo pigment, resulting in only partial loss of the tattooed skin.

Conservative thickness layers are performed intradermally, similar to removing traditional layers in MMS. For treatment of NMSCs, a margin is scored around the lesion, and then the blade is passed carefully under the lesion nearly parallel to the skin through an intradermal plane. It is important to avoid entering the subcuticular fat (Figure 1). The tissue then is processed normally in the Mohs laboratory for complete circumferential margin evaluation. If necessary and possible, subsequent layers also can be performed in the intradermal plane. Once total circumferential margin control is obtained, the wound is allowed to granulate and heal by secondary intention. As these processes occur, we have found that wound contraction is less likely with the dermis intact, resulting in less impact on the overall appearance of the tattoo (Figures 1 and 2). For very thin lesions, resultant defects may retain some residual tattoo pigment. The residual scars also may be responsive to tattoo revision, although a period of monitoring for recurrence should be considered if there is concern that revising the tattoo could obscure early recurrent tumors. From our experience, utilizing CTL for NMSCs that arise within or near tattoos results in favorable preservation of the tattoo appearance and high patient satisfaction.

The procedure is performed similarly for removal of allergenic tattoo pigment, with careful excision to the mid dermis. Since the areas affected by the cutaneous reaction may be relatively large, surgical precision is required to maintain a uniform depth to remove the tattoo pigment and preserve the deep dermis (Figure 2). Once removed, the defect can be left to granulate and heal by secondary intention. If the patient wants to have the tattoo revised in the future, it would be prudent to utilize pigment that the patient has responded favorably to. In our experience, this approach is effective and yields high patient satisfaction and minimizes morbidity.

Practice Implications

Tattoos often hold special meaning for patients; therefore, treatment of pathologies arising in or near tattooed skin should emphasize maintaining the appearance of the tattoo while still being effective. Conservative thickness layers in MMS and intradermal excisions for allergic reactions to tattoo pigment are an effective treatment strategy that clinicians may consider.

One shortcoming of using CTL for MMS is the need for subsequent layers to clear the tumor; however, data suggest that first-stage cure rates are extremely high even with CTL for appropriately selected patients, with clearance of nearly 80% of tumors on the first stage. Tumors that may be most responsive to CTL include exophytic NMSCs and those arising in areas with a thicker dermis, including the back, legs, and scalp, although other locations including the face, hands, shins, ankles, and feet also may be well suited for CTL.⁴ Another shortcoming of CTL is that skin cancers arising in tattoos may not be considered appropriate for MMS based on the 2012 Appropriate Use Criteria, which consider factors such as location, type of cancer, size of the lesion, and patient characteristics to determine whether a skin cancer is appropriate for treatment with MMS.⁶ When the Appropriate Use Criteria categorizes a cancer as uncertain or inappropriate for MMS, the clinician must use their clinical judgment to determine whether MMS is the preferred treatment approach.⁷ Given the cosmetic significance of tattoos, location of a skin cancer near a tattoo could be taken into account for skin cancers that might otherwise not meet Appropriate Use Criteria. 

Conservative thickness layers in MMS and intradermal excisions of tattoo pigment are both effective techniques of minimizing disruption of tattoos while effectively treating patients.

Practice Gap

Tattoos have become increasingly prevalent in Western culture, with approximately 1 in 4 Americans having at least 1 tattoo. Individuals invest money, time, and even pain in getting tattoos, many of which hold special personal, family, or religious significance.¹ Various cutaneous pathologies may arise in areas of the skin with tattoos, including malignancies and inflammatory reactions to tattoo pigment, and in these cases, surgical management may be indicated.^2,3

Nonmelanoma skin cancers (NMSCs) such as superficial basal cell carcinomas on broadly sun-damaged areas (eg, trunk, torso), squamous cell carcinomas, reactive keratoacanthomas, and reactive pseudoepitheliomatous squamous hyperplasia diagnosed as squamous cell carcinoma have been reported to occur in or near areas of the skin with tattoos.² Mohs micrographic surgery (MMS) is the standard of care for removing NMSCs, particularly when they manifest in cosmetically sensitive areas.⁴ This treatment option allows for careful guided resection of tumors to minimize the risk for recurrence; it also preserves healthy tissue, which typically results in a smaller radial defect after the procedure is complete. 

Chronic reactions to tattoo pigment may include granulomatous tattoo reactions and pseudolymphomas.³ Treatment options may include immunosuppressives such as intralesional triamcinolone as well as pigment destruction via lasers⁵; however, not all tattoos are responsive to these treatments. Surgical excision is an effective and definitive treatment in this context, as tattoo pigment resides in or above the mid dermis to a depth of approximately 400 μm. Intradermal excision effectively removes the antigenic pigment.⁵

In these clinical scenarios, patients may be hesitant to pursue surgical treatment due to concerns that it may alter tattoo appearance. Many clinicians and surgeons may consider definitive treatment and tattoo preservation to be mutually exclusive, but this is not always the case. We propose a technique that utilizes conservative thickness layers (CTL) to minimize disruption to the appearance of tattoos in MMS for treatment of cutaneous malignancies as well as intradermal excision of tattoo pigment in the setting of chronic inflammatory tattoo reactions.

The Technique

In the appropriate clinical context, CTL can effectively result in defects that heal well by secondary intention and minimize collateral tissue distortion.⁴ Lesions manifesting in or near tattooed skin often are responsive to treatment with CTL; furthermore, CTL may preserve some deeper tattoo pigment, resulting in only partial loss of the tattooed skin.

Conservative thickness layers are performed intradermally, similar to removing traditional layers in MMS. For treatment of NMSCs, a margin is scored around the lesion, and then the blade is passed carefully under the lesion nearly parallel to the skin through an intradermal plane. It is important to avoid entering the subcuticular fat (Figure 1). The tissue then is processed normally in the Mohs laboratory for complete circumferential margin evaluation. If necessary and possible, subsequent layers also can be performed in the intradermal plane. Once total circumferential margin control is obtained, the wound is allowed to granulate and heal by secondary intention. As these processes occur, we have found that wound contraction is less likely with the dermis intact, resulting in less impact on the overall appearance of the tattoo (Figures 1 and 2). For very thin lesions, resultant defects may retain some residual tattoo pigment. The residual scars also may be responsive to tattoo revision, although a period of monitoring for recurrence should be considered if there is concern that revising the tattoo could obscure early recurrent tumors. From our experience, utilizing CTL for NMSCs that arise within or near tattoos results in favorable preservation of the tattoo appearance and high patient satisfaction.

The procedure is performed similarly for removal of allergenic tattoo pigment, with careful excision to the mid dermis. Since the areas affected by the cutaneous reaction may be relatively large, surgical precision is required to maintain a uniform depth to remove the tattoo pigment and preserve the deep dermis (Figure 2). Once removed, the defect can be left to granulate and heal by secondary intention. If the patient wants to have the tattoo revised in the future, it would be prudent to utilize pigment that the patient has responded favorably to. In our experience, this approach is effective and yields high patient satisfaction and minimizes morbidity.

Practice Implications

Tattoos often hold special meaning for patients; therefore, treatment of pathologies arising in or near tattooed skin should emphasize maintaining the appearance of the tattoo while still being effective. Conservative thickness layers in MMS and intradermal excisions for allergic reactions to tattoo pigment are an effective treatment strategy that clinicians may consider.

One shortcoming of using CTL for MMS is the need for subsequent layers to clear the tumor; however, data suggest that first-stage cure rates are extremely high even with CTL for appropriately selected patients, with clearance of nearly 80% of tumors on the first stage. Tumors that may be most responsive to CTL include exophytic NMSCs and those arising in areas with a thicker dermis, including the back, legs, and scalp, although other locations including the face, hands, shins, ankles, and feet also may be well suited for CTL.⁴ Another shortcoming of CTL is that skin cancers arising in tattoos may not be considered appropriate for MMS based on the 2012 Appropriate Use Criteria, which consider factors such as location, type of cancer, size of the lesion, and patient characteristics to determine whether a skin cancer is appropriate for treatment with MMS.⁶ When the Appropriate Use Criteria categorizes a cancer as uncertain or inappropriate for MMS, the clinician must use their clinical judgment to determine whether MMS is the preferred treatment approach.⁷ Given the cosmetic significance of tattoos, location of a skin cancer near a tattoo could be taken into account for skin cancers that might otherwise not meet Appropriate Use Criteria. 

Conservative thickness layers in MMS and intradermal excisions of tattoo pigment are both effective techniques of minimizing disruption of tattoos while effectively treating patients.

THE DIAGNOSIS: Squamoid Eccrine Ductal Carcinoma

Immunohistochemical staining of the biopsy specimen showed neoplastic aggregates that were diffusely positive for pancytokeratin and strongly positive for cytokeratin (CK) 5/6. Epithelial membrane antigen (EMA) and CK7 also were positive, CAM 5.2 was partially positive, and carcinoembryonic antigen (CEA) was focally positive (periluminal); S100 was negative. Given the histologic findings of irregular infiltrative cords and stranding exhibiting ductal differentiation in a fibrotic stroma in combination with the staining pattern, a diagnosis of squamous eccrine ductal carcinoma (SEDC) was made.

Squamoid eccrine ductal carcinoma is a rare primary cutaneous tumor with aggressive features that can be confused both clinically and histologically with squamous cell carcinoma (SCC). Histologically, SEDC is a biphasic tumor. If a shallow histologic specimen is obtained, it may be indistinguishable from a well-differentiated SCC (Figure 1). A deeper biopsy reveals irregular infiltrative cords and strands exhibiting ductal differentiation in a fibrotic stroma.¹

The immunohistochemical staining pattern of SEDC is similar to that of SCC, showing diffuse staining with pancytokeratin (AE1/AE3), CK 5/6, CK7, p63, and EMA. What distinguishes SEDC from SCC is that CEA highlights areas of glandular differentiation. An additional histologic feature seen commonly with SEDC is perineural invasion.

The etiology of SEDC remains controversial; although it originally was considered an aggressive variant of SCC along the same continuum as adenosquamous carcinoma, the fifth edition of the WHO Classification of Skin Tumors² has categorized SEDC as an adnexal neoplasm. Our patient demonstrated an atypical presentation of this tumor, which has been most commonly described in the literature as manifesting on the head, neck, or upper extremities in older adults.³ Mohs micrographic surgery is the recommended treatment for this aggressive tumor.³

The differential diagnosis for SEDC includes microcystic adnexal carcinoma, porocarcinoma, and eccrine syringofibroadenoma. Microcystic adnexal carcinoma is a rare, low-grade tumor of the sweat glands that typically manifests as a firm pink papule or plaque in the head and neck region. Microscopically, it demonstrates cords of basaloid cells in a paisley-tie tadpole pattern with a dense pink to red stroma and horn cysts (Figure 2). Histologic differential diagnoses include syringoma, morpheaform basal cell carcinoma, desmoplastic trichoepithelioma, and trichoadenoma. Carcinoembryonic antigen stains positive in microcystic adnexal carcinoma, which helps distinguish it from basal cell carcinoma and SCC. Surgical excision or Mohs surgery are recommended for management.⁴

Porocarcinoma is a malignant skin tumor that originates from the intraepidermal sweat gland ducts. It also has been proposed that porocarcinoma develops from benign eccrine poroma. Porocarcinoma often is seen in elderly individuals, with a predilection for the lower extremities. Porocarcinoma demonstrates diverse clinical and histopathologic features, which can make diagnosis challenging. Histopathologically, porocarcinoma has an infiltrative growth pattern, with large basaloid epithelial cells that demonstrate ductal differentiation, cytologic atypia, increased mitotic activity, and tumor necrosis (Figure 3). Some porocarcinomas may exhibit squamous-cell, spindle-cell, or clear-cell differentiation. Neoplastic cells stain positive for CEA, EMA, and CD117, which can assist in distinguishing porocarcinoma from cutaneous SCC.⁵

Eccrine syringofibroadenoma is an unusual benign cutaneous adnexal tumor that manifests mostly in individuals aged 40 years or older. It develops as single or multiple lesions that usually affect the lower extremities. Histologically, eccrine syringofibroadenoma demonstrates unique findings of anastomosing ducts and monomorphous epithelial cells within a fibrovascular stroma (Figure 4). On immunohistochemistry, it stains positive for EMA, CEA, high-molecular-weight kininogen, and filaggrin.⁶ Periodic acid–Schiff staining also is positive.

THE DIAGNOSIS: Squamoid Eccrine Ductal Carcinoma

Immunohistochemical staining of the biopsy specimen showed neoplastic aggregates that were diffusely positive for pancytokeratin and strongly positive for cytokeratin (CK) 5/6. Epithelial membrane antigen (EMA) and CK7 also were positive, CAM 5.2 was partially positive, and carcinoembryonic antigen (CEA) was focally positive (periluminal); S100 was negative. Given the histologic findings of irregular infiltrative cords and stranding exhibiting ductal differentiation in a fibrotic stroma in combination with the staining pattern, a diagnosis of squamous eccrine ductal carcinoma (SEDC) was made.

Squamoid eccrine ductal carcinoma is a rare primary cutaneous tumor with aggressive features that can be confused both clinically and histologically with squamous cell carcinoma (SCC). Histologically, SEDC is a biphasic tumor. If a shallow histologic specimen is obtained, it may be indistinguishable from a well-differentiated SCC (Figure 1). A deeper biopsy reveals irregular infiltrative cords and strands exhibiting ductal differentiation in a fibrotic stroma.¹

The immunohistochemical staining pattern of SEDC is similar to that of SCC, showing diffuse staining with pancytokeratin (AE1/AE3), CK 5/6, CK7, p63, and EMA. What distinguishes SEDC from SCC is that CEA highlights areas of glandular differentiation. An additional histologic feature seen commonly with SEDC is perineural invasion.

The etiology of SEDC remains controversial; although it originally was considered an aggressive variant of SCC along the same continuum as adenosquamous carcinoma, the fifth edition of the WHO Classification of Skin Tumors² has categorized SEDC as an adnexal neoplasm. Our patient demonstrated an atypical presentation of this tumor, which has been most commonly described in the literature as manifesting on the head, neck, or upper extremities in older adults.³ Mohs micrographic surgery is the recommended treatment for this aggressive tumor.³

The differential diagnosis for SEDC includes microcystic adnexal carcinoma, porocarcinoma, and eccrine syringofibroadenoma. Microcystic adnexal carcinoma is a rare, low-grade tumor of the sweat glands that typically manifests as a firm pink papule or plaque in the head and neck region. Microscopically, it demonstrates cords of basaloid cells in a paisley-tie tadpole pattern with a dense pink to red stroma and horn cysts (Figure 2). Histologic differential diagnoses include syringoma, morpheaform basal cell carcinoma, desmoplastic trichoepithelioma, and trichoadenoma. Carcinoembryonic antigen stains positive in microcystic adnexal carcinoma, which helps distinguish it from basal cell carcinoma and SCC. Surgical excision or Mohs surgery are recommended for management.⁴

Porocarcinoma is a malignant skin tumor that originates from the intraepidermal sweat gland ducts. It also has been proposed that porocarcinoma develops from benign eccrine poroma. Porocarcinoma often is seen in elderly individuals, with a predilection for the lower extremities. Porocarcinoma demonstrates diverse clinical and histopathologic features, which can make diagnosis challenging. Histopathologically, porocarcinoma has an infiltrative growth pattern, with large basaloid epithelial cells that demonstrate ductal differentiation, cytologic atypia, increased mitotic activity, and tumor necrosis (Figure 3). Some porocarcinomas may exhibit squamous-cell, spindle-cell, or clear-cell differentiation. Neoplastic cells stain positive for CEA, EMA, and CD117, which can assist in distinguishing porocarcinoma from cutaneous SCC.⁵

Eccrine syringofibroadenoma is an unusual benign cutaneous adnexal tumor that manifests mostly in individuals aged 40 years or older. It develops as single or multiple lesions that usually affect the lower extremities. Histologically, eccrine syringofibroadenoma demonstrates unique findings of anastomosing ducts and monomorphous epithelial cells within a fibrovascular stroma (Figure 4). On immunohistochemistry, it stains positive for EMA, CEA, high-molecular-weight kininogen, and filaggrin.⁶ Periodic acid–Schiff staining also is positive.

THE DIAGNOSIS: Squamoid Eccrine Ductal Carcinoma

Immunohistochemical staining of the biopsy specimen showed neoplastic aggregates that were diffusely positive for pancytokeratin and strongly positive for cytokeratin (CK) 5/6. Epithelial membrane antigen (EMA) and CK7 also were positive, CAM 5.2 was partially positive, and carcinoembryonic antigen (CEA) was focally positive (periluminal); S100 was negative. Given the histologic findings of irregular infiltrative cords and stranding exhibiting ductal differentiation in a fibrotic stroma in combination with the staining pattern, a diagnosis of squamous eccrine ductal carcinoma (SEDC) was made.

Squamoid eccrine ductal carcinoma is a rare primary cutaneous tumor with aggressive features that can be confused both clinically and histologically with squamous cell carcinoma (SCC). Histologically, SEDC is a biphasic tumor. If a shallow histologic specimen is obtained, it may be indistinguishable from a well-differentiated SCC (Figure 1). A deeper biopsy reveals irregular infiltrative cords and strands exhibiting ductal differentiation in a fibrotic stroma.¹

The immunohistochemical staining pattern of SEDC is similar to that of SCC, showing diffuse staining with pancytokeratin (AE1/AE3), CK 5/6, CK7, p63, and EMA. What distinguishes SEDC from SCC is that CEA highlights areas of glandular differentiation. An additional histologic feature seen commonly with SEDC is perineural invasion.

The etiology of SEDC remains controversial; although it originally was considered an aggressive variant of SCC along the same continuum as adenosquamous carcinoma, the fifth edition of the WHO Classification of Skin Tumors² has categorized SEDC as an adnexal neoplasm. Our patient demonstrated an atypical presentation of this tumor, which has been most commonly described in the literature as manifesting on the head, neck, or upper extremities in older adults.³ Mohs micrographic surgery is the recommended treatment for this aggressive tumor.³

The differential diagnosis for SEDC includes microcystic adnexal carcinoma, porocarcinoma, and eccrine syringofibroadenoma. Microcystic adnexal carcinoma is a rare, low-grade tumor of the sweat glands that typically manifests as a firm pink papule or plaque in the head and neck region. Microscopically, it demonstrates cords of basaloid cells in a paisley-tie tadpole pattern with a dense pink to red stroma and horn cysts (Figure 2). Histologic differential diagnoses include syringoma, morpheaform basal cell carcinoma, desmoplastic trichoepithelioma, and trichoadenoma. Carcinoembryonic antigen stains positive in microcystic adnexal carcinoma, which helps distinguish it from basal cell carcinoma and SCC. Surgical excision or Mohs surgery are recommended for management.⁴

Porocarcinoma is a malignant skin tumor that originates from the intraepidermal sweat gland ducts. It also has been proposed that porocarcinoma develops from benign eccrine poroma. Porocarcinoma often is seen in elderly individuals, with a predilection for the lower extremities. Porocarcinoma demonstrates diverse clinical and histopathologic features, which can make diagnosis challenging. Histopathologically, porocarcinoma has an infiltrative growth pattern, with large basaloid epithelial cells that demonstrate ductal differentiation, cytologic atypia, increased mitotic activity, and tumor necrosis (Figure 3). Some porocarcinomas may exhibit squamous-cell, spindle-cell, or clear-cell differentiation. Neoplastic cells stain positive for CEA, EMA, and CD117, which can assist in distinguishing porocarcinoma from cutaneous SCC.⁵

Eccrine syringofibroadenoma is an unusual benign cutaneous adnexal tumor that manifests mostly in individuals aged 40 years or older. It develops as single or multiple lesions that usually affect the lower extremities. Histologically, eccrine syringofibroadenoma demonstrates unique findings of anastomosing ducts and monomorphous epithelial cells within a fibrovascular stroma (Figure 4). On immunohistochemistry, it stains positive for EMA, CEA, high-molecular-weight kininogen, and filaggrin.⁶ Periodic acid–Schiff staining also is positive.

Purpose

Skin adnexal tumors (SAT) include a group of benign and malignant appendageal tumors that arise from hair follicles, sebaceous glands, or sweat glands. They typically appear as small, painless bumps or nodules on the skin, and are more common in men compared to women. The 5-year overall SAT survival rate ranges from 74-90%. To better understand the differences in survival outcomes based on subtypes of SAT, the National Cancer Database (NCDB) was analyzed.

Methods

A retrospective cohort study of 11,627 patients with histologically confirmed SAT between 2004 and 2021 was conducted across 1,500 Commission on Cancer facilities located in the US and Puerto Rico. Demographic factors such as sex, age, and race were analyzed using Pearson Chi-squared tests, and survival outcomes were analyzed by Kaplan- Meier survival analysis. P value < 0.05 was considered statistically significant.

Results

Most patients with SAT were male (57.3%). The average age at diagnosis was 65.9 (SD=14.4, range 0-90). Of the patient sample, 87.2% were White, 7.6% Black, 2.5% Asian, and 2.7% other. Several subtypes disproportionately affected Black individuals, including apocrine adenocarcinoma (15.7%) and hidradenocarcinoma (13.6%). The estimated 5-year survival of SAT was 74.9% with an overall survival of 135.8 months (SE=1.1). Sebaceous carcinoma (which accounts for 41.8% of all cases) had the lowest average survival time of 119.6 months (SE=1.8), while digital papillary adenocarcinoma had the highest survival at around 183.5 months (SE=4.6).

Conclusions

This study supports a higher frequency of SAT among men. While White patients were more likely to get SAT overall, including the most common sebaceous carcinoma, Black race were associated with higher frequency of rarer subtypes. The average age of diagnosis of SAT mimics other non-melanoma skin cancers, but has a lower overall survival rate. Future studies should consider other risk factors that may be impacting the differences in survival outcomes to guide treatment and address health disparities among the various subtypes.

Purpose

Skin adnexal tumors (SAT) include a group of benign and malignant appendageal tumors that arise from hair follicles, sebaceous glands, or sweat glands. They typically appear as small, painless bumps or nodules on the skin, and are more common in men compared to women. The 5-year overall SAT survival rate ranges from 74-90%. To better understand the differences in survival outcomes based on subtypes of SAT, the National Cancer Database (NCDB) was analyzed.

Methods

A retrospective cohort study of 11,627 patients with histologically confirmed SAT between 2004 and 2021 was conducted across 1,500 Commission on Cancer facilities located in the US and Puerto Rico. Demographic factors such as sex, age, and race were analyzed using Pearson Chi-squared tests, and survival outcomes were analyzed by Kaplan- Meier survival analysis. P value < 0.05 was considered statistically significant.

Results

Most patients with SAT were male (57.3%). The average age at diagnosis was 65.9 (SD=14.4, range 0-90). Of the patient sample, 87.2% were White, 7.6% Black, 2.5% Asian, and 2.7% other. Several subtypes disproportionately affected Black individuals, including apocrine adenocarcinoma (15.7%) and hidradenocarcinoma (13.6%). The estimated 5-year survival of SAT was 74.9% with an overall survival of 135.8 months (SE=1.1). Sebaceous carcinoma (which accounts for 41.8% of all cases) had the lowest average survival time of 119.6 months (SE=1.8), while digital papillary adenocarcinoma had the highest survival at around 183.5 months (SE=4.6).

Conclusions

This study supports a higher frequency of SAT among men. While White patients were more likely to get SAT overall, including the most common sebaceous carcinoma, Black race were associated with higher frequency of rarer subtypes. The average age of diagnosis of SAT mimics other non-melanoma skin cancers, but has a lower overall survival rate. Future studies should consider other risk factors that may be impacting the differences in survival outcomes to guide treatment and address health disparities among the various subtypes.

Purpose

Skin adnexal tumors (SAT) include a group of benign and malignant appendageal tumors that arise from hair follicles, sebaceous glands, or sweat glands. They typically appear as small, painless bumps or nodules on the skin, and are more common in men compared to women. The 5-year overall SAT survival rate ranges from 74-90%. To better understand the differences in survival outcomes based on subtypes of SAT, the National Cancer Database (NCDB) was analyzed.

Methods

A retrospective cohort study of 11,627 patients with histologically confirmed SAT between 2004 and 2021 was conducted across 1,500 Commission on Cancer facilities located in the US and Puerto Rico. Demographic factors such as sex, age, and race were analyzed using Pearson Chi-squared tests, and survival outcomes were analyzed by Kaplan- Meier survival analysis. P value < 0.05 was considered statistically significant.

Results

Most patients with SAT were male (57.3%). The average age at diagnosis was 65.9 (SD=14.4, range 0-90). Of the patient sample, 87.2% were White, 7.6% Black, 2.5% Asian, and 2.7% other. Several subtypes disproportionately affected Black individuals, including apocrine adenocarcinoma (15.7%) and hidradenocarcinoma (13.6%). The estimated 5-year survival of SAT was 74.9% with an overall survival of 135.8 months (SE=1.1). Sebaceous carcinoma (which accounts for 41.8% of all cases) had the lowest average survival time of 119.6 months (SE=1.8), while digital papillary adenocarcinoma had the highest survival at around 183.5 months (SE=4.6).

Conclusions

This study supports a higher frequency of SAT among men. While White patients were more likely to get SAT overall, including the most common sebaceous carcinoma, Black race were associated with higher frequency of rarer subtypes. The average age of diagnosis of SAT mimics other non-melanoma skin cancers, but has a lower overall survival rate. Future studies should consider other risk factors that may be impacting the differences in survival outcomes to guide treatment and address health disparities among the various subtypes.