Photo Challenge

THE DIAGNOSIS: Cutaneous Leiomyosarcoma

Based on the clinical and histopathologic findings, our patient was diagnosed with primary cutaneous leiomyosarcoma (LMS), a rare soft-tissue neoplasm that arises from smooth muscle and typically manifests as a firm pink nodule.¹ The neoplasm may occur in the area of a prior traumatic injury or develop spontaneously without an identifiable cause.^1-3 Cutaneous LMS represents 2% to 3% of all soft-tissue sarcomas worldwide, with an estimated incidence of 1 in 500,000 annually.^1,4 Men who are in their fifth to seventh decades of life are at the highest risk for LMS.¹

Histologically, cutaneous LMS can be subclassified as dermal, which has a low metastatic risk and excellent prognosis, or subcutaneous, which is associated with poorer outcomes and vascular muscle origin.¹ In our case, hematoxylin and eosin staining revealed fascicles of smooth muscle fibers with hypercellularity, atypia, and mitotic figures (Figure). The neoplasm stained positive for desmin, vimentin, and smooth muscle actin and negative for SOX10, Melan-A, PRAME (preferentially expressed antigen in melanoma), CD34, and Factor XIIIa.¹

Standard treatment for LMS is surgical excision.⁵ Poor prognostic factors include lesions with a diameter of 5 cm or larger, deep subcutaneous tumor invasion, and distant metastases.^2,5

The differential diagnosis may include dermatofibrosarcoma protuberans, which can have a similar pink nodular appearance and also may manifest after injury⁶; however, this lesion would stain positive for CD34 on histopathology.¹ Nodular melanoma also can manifest as a solitary red, raised lesion, but it would stain positive for SOX10, PRAME, and Melan-A on histopathology.⁷ Basal cell carcinoma, which also may have a similar clinical appearance, is associated with nests of basaloid cells and palisading nuclei histologically.⁸ Lastly, atypical fibroxanthoma also manifests as a red nodule or plaque and is associated with atypical mitotic figures on histology; however, it notably stains negative for desmin.⁹

In summary, cutaneous LMS should be included in the differential diagnosis for raised, pink nodules. Given its nonspecific clinical presentation, this rare and malignant neoplasm requires biopsy and immunohistochemical staining for accurate diagnosis.

THE DIAGNOSIS: Cutaneous Leiomyosarcoma

Based on the clinical and histopathologic findings, our patient was diagnosed with primary cutaneous leiomyosarcoma (LMS), a rare soft-tissue neoplasm that arises from smooth muscle and typically manifests as a firm pink nodule.¹ The neoplasm may occur in the area of a prior traumatic injury or develop spontaneously without an identifiable cause.^1-3 Cutaneous LMS represents 2% to 3% of all soft-tissue sarcomas worldwide, with an estimated incidence of 1 in 500,000 annually.^1,4 Men who are in their fifth to seventh decades of life are at the highest risk for LMS.¹

Histologically, cutaneous LMS can be subclassified as dermal, which has a low metastatic risk and excellent prognosis, or subcutaneous, which is associated with poorer outcomes and vascular muscle origin.¹ In our case, hematoxylin and eosin staining revealed fascicles of smooth muscle fibers with hypercellularity, atypia, and mitotic figures (Figure). The neoplasm stained positive for desmin, vimentin, and smooth muscle actin and negative for SOX10, Melan-A, PRAME (preferentially expressed antigen in melanoma), CD34, and Factor XIIIa.¹

Standard treatment for LMS is surgical excision.⁵ Poor prognostic factors include lesions with a diameter of 5 cm or larger, deep subcutaneous tumor invasion, and distant metastases.^2,5

The differential diagnosis may include dermatofibrosarcoma protuberans, which can have a similar pink nodular appearance and also may manifest after injury⁶; however, this lesion would stain positive for CD34 on histopathology.¹ Nodular melanoma also can manifest as a solitary red, raised lesion, but it would stain positive for SOX10, PRAME, and Melan-A on histopathology.⁷ Basal cell carcinoma, which also may have a similar clinical appearance, is associated with nests of basaloid cells and palisading nuclei histologically.⁸ Lastly, atypical fibroxanthoma also manifests as a red nodule or plaque and is associated with atypical mitotic figures on histology; however, it notably stains negative for desmin.⁹

In summary, cutaneous LMS should be included in the differential diagnosis for raised, pink nodules. Given its nonspecific clinical presentation, this rare and malignant neoplasm requires biopsy and immunohistochemical staining for accurate diagnosis.

THE DIAGNOSIS: Cutaneous Leiomyosarcoma

Based on the clinical and histopathologic findings, our patient was diagnosed with primary cutaneous leiomyosarcoma (LMS), a rare soft-tissue neoplasm that arises from smooth muscle and typically manifests as a firm pink nodule.¹ The neoplasm may occur in the area of a prior traumatic injury or develop spontaneously without an identifiable cause.^1-3 Cutaneous LMS represents 2% to 3% of all soft-tissue sarcomas worldwide, with an estimated incidence of 1 in 500,000 annually.^1,4 Men who are in their fifth to seventh decades of life are at the highest risk for LMS.¹

Histologically, cutaneous LMS can be subclassified as dermal, which has a low metastatic risk and excellent prognosis, or subcutaneous, which is associated with poorer outcomes and vascular muscle origin.¹ In our case, hematoxylin and eosin staining revealed fascicles of smooth muscle fibers with hypercellularity, atypia, and mitotic figures (Figure). The neoplasm stained positive for desmin, vimentin, and smooth muscle actin and negative for SOX10, Melan-A, PRAME (preferentially expressed antigen in melanoma), CD34, and Factor XIIIa.¹

Standard treatment for LMS is surgical excision.⁵ Poor prognostic factors include lesions with a diameter of 5 cm or larger, deep subcutaneous tumor invasion, and distant metastases.^2,5

The differential diagnosis may include dermatofibrosarcoma protuberans, which can have a similar pink nodular appearance and also may manifest after injury⁶; however, this lesion would stain positive for CD34 on histopathology.¹ Nodular melanoma also can manifest as a solitary red, raised lesion, but it would stain positive for SOX10, PRAME, and Melan-A on histopathology.⁷ Basal cell carcinoma, which also may have a similar clinical appearance, is associated with nests of basaloid cells and palisading nuclei histologically.⁸ Lastly, atypical fibroxanthoma also manifests as a red nodule or plaque and is associated with atypical mitotic figures on histology; however, it notably stains negative for desmin.⁹

In summary, cutaneous LMS should be included in the differential diagnosis for raised, pink nodules. Given its nonspecific clinical presentation, this rare and malignant neoplasm requires biopsy and immunohistochemical staining for accurate 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.

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: Pseudopsoriatic Nails With Pterygium Inversum Unguis

Based on the clinical findings and the patient’s history of gel manicures, a diagnosis of pseudopsoriatic nails with pterygium inversum unguis (PIU) was made. The patient was advised to avoid gel manicures and any other chemical or mechanical trauma to the nails. No other treatment was administered. Improvements including healthy nail growth and disappearing color and structure changes within the nail plates were noted at 2 months’ follow-up.

The durability and availability of gel manicures has been increasingly popular due to their ideal cosmetic results. A gel manicure involves applying a gel nail polish (GNP) containing acrylate or methacrylate monomers that harden after exposure to UV light through a photopolymerization reaction. Acrylate polymers including ethylene glycol dimethacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, methyl methacrylate, and tetrahydrofurfuryl methacrylate are known to cause allergic contact dermatitis in patients who wear acrylate-based GNP.¹Hydroxyethyl methacrylate is the most common sensitizer among these acrylates. Fingertip dry dermatitis, fissured painful pulpitis of the fingers, and periungual erythema are the most common manifestations of methacrylate allergy; however, there also are reports of onycholysis and onychodystrophy in patients with severe allergic contact dermatitis caused by acrylates.^2,3

In contrast to common public misconception that GNP may strengthen the nails, scientific evidence has shown otherwise. Besides allergic contact dermatitis, mechanical damage and UV-induced skin manifestations have been reported in association with GNP.^1,3,4 Pseudopsoriatic nails are characterized by onycholysis accompanied by subungual hyperkeratosis, closely resembling the nail findings seen in psoriasis. This condition may occur due to mechanical damage and acrylate sensitization.^2,4 Pterygium inversum unguis, also known as ventral pterygium, occurs as a result of hyponychium trauma due to either application or removal processes of GNP and/ or exposure to chemical ingredients and is one of the most striking clinical manifestations of GNP use.⁵ In our patient, all fingernails were affected by PIU.

Patients presenting with pseudopsoriatic nail changes and/or PIU should be questioned about potential exposure to GNP and/or sculpted nails, also known as custom artificial nails or nail prostheses. Diagnosis primarily is made clinically, but microbial cultures or skin biopsy may be required to exclude psoriasis and fungal infections in some patients. Patch testing with acrylate series in particular also is necessary in patients presenting with hand dermatitis. As it is the most common contact sensitizer in the acrylic material of the GNPs, screening for 2-hydroxyethyl methacrylate allergy is recommended in these patients.¹ Almost all adverse effects related to use of GNP may be reversible upon discontinuation of exposure.

THE DIAGNOSIS: Pseudopsoriatic Nails With Pterygium Inversum Unguis

Based on the clinical findings and the patient’s history of gel manicures, a diagnosis of pseudopsoriatic nails with pterygium inversum unguis (PIU) was made. The patient was advised to avoid gel manicures and any other chemical or mechanical trauma to the nails. No other treatment was administered. Improvements including healthy nail growth and disappearing color and structure changes within the nail plates were noted at 2 months’ follow-up.

The durability and availability of gel manicures has been increasingly popular due to their ideal cosmetic results. A gel manicure involves applying a gel nail polish (GNP) containing acrylate or methacrylate monomers that harden after exposure to UV light through a photopolymerization reaction. Acrylate polymers including ethylene glycol dimethacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, methyl methacrylate, and tetrahydrofurfuryl methacrylate are known to cause allergic contact dermatitis in patients who wear acrylate-based GNP.¹Hydroxyethyl methacrylate is the most common sensitizer among these acrylates. Fingertip dry dermatitis, fissured painful pulpitis of the fingers, and periungual erythema are the most common manifestations of methacrylate allergy; however, there also are reports of onycholysis and onychodystrophy in patients with severe allergic contact dermatitis caused by acrylates.^2,3

In contrast to common public misconception that GNP may strengthen the nails, scientific evidence has shown otherwise. Besides allergic contact dermatitis, mechanical damage and UV-induced skin manifestations have been reported in association with GNP.^1,3,4 Pseudopsoriatic nails are characterized by onycholysis accompanied by subungual hyperkeratosis, closely resembling the nail findings seen in psoriasis. This condition may occur due to mechanical damage and acrylate sensitization.^2,4 Pterygium inversum unguis, also known as ventral pterygium, occurs as a result of hyponychium trauma due to either application or removal processes of GNP and/ or exposure to chemical ingredients and is one of the most striking clinical manifestations of GNP use.⁵ In our patient, all fingernails were affected by PIU.

Patients presenting with pseudopsoriatic nail changes and/or PIU should be questioned about potential exposure to GNP and/or sculpted nails, also known as custom artificial nails or nail prostheses. Diagnosis primarily is made clinically, but microbial cultures or skin biopsy may be required to exclude psoriasis and fungal infections in some patients. Patch testing with acrylate series in particular also is necessary in patients presenting with hand dermatitis. As it is the most common contact sensitizer in the acrylic material of the GNPs, screening for 2-hydroxyethyl methacrylate allergy is recommended in these patients.¹ Almost all adverse effects related to use of GNP may be reversible upon discontinuation of exposure.

THE DIAGNOSIS: Pseudopsoriatic Nails With Pterygium Inversum Unguis

Based on the clinical findings and the patient’s history of gel manicures, a diagnosis of pseudopsoriatic nails with pterygium inversum unguis (PIU) was made. The patient was advised to avoid gel manicures and any other chemical or mechanical trauma to the nails. No other treatment was administered. Improvements including healthy nail growth and disappearing color and structure changes within the nail plates were noted at 2 months’ follow-up.

The durability and availability of gel manicures has been increasingly popular due to their ideal cosmetic results. A gel manicure involves applying a gel nail polish (GNP) containing acrylate or methacrylate monomers that harden after exposure to UV light through a photopolymerization reaction. Acrylate polymers including ethylene glycol dimethacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, methyl methacrylate, and tetrahydrofurfuryl methacrylate are known to cause allergic contact dermatitis in patients who wear acrylate-based GNP.¹Hydroxyethyl methacrylate is the most common sensitizer among these acrylates. Fingertip dry dermatitis, fissured painful pulpitis of the fingers, and periungual erythema are the most common manifestations of methacrylate allergy; however, there also are reports of onycholysis and onychodystrophy in patients with severe allergic contact dermatitis caused by acrylates.^2,3

In contrast to common public misconception that GNP may strengthen the nails, scientific evidence has shown otherwise. Besides allergic contact dermatitis, mechanical damage and UV-induced skin manifestations have been reported in association with GNP.^1,3,4 Pseudopsoriatic nails are characterized by onycholysis accompanied by subungual hyperkeratosis, closely resembling the nail findings seen in psoriasis. This condition may occur due to mechanical damage and acrylate sensitization.^2,4 Pterygium inversum unguis, also known as ventral pterygium, occurs as a result of hyponychium trauma due to either application or removal processes of GNP and/ or exposure to chemical ingredients and is one of the most striking clinical manifestations of GNP use.⁵ In our patient, all fingernails were affected by PIU.

Patients presenting with pseudopsoriatic nail changes and/or PIU should be questioned about potential exposure to GNP and/or sculpted nails, also known as custom artificial nails or nail prostheses. Diagnosis primarily is made clinically, but microbial cultures or skin biopsy may be required to exclude psoriasis and fungal infections in some patients. Patch testing with acrylate series in particular also is necessary in patients presenting with hand dermatitis. As it is the most common contact sensitizer in the acrylic material of the GNPs, screening for 2-hydroxyethyl methacrylate allergy is recommended in these patients.¹ Almost all adverse effects related to use of GNP may be reversible upon discontinuation of exposure.

THE DIAGNOSIS: Black Dermographism

Black dermographism is characterized by asymptomatic black discoloration on the skin caused by contact with various metals, most commonly gold but also silver, nickel, zinc, lead, and aluminum.¹ These metallic particles have a black appearance as they do not reflect light.² Our patient was wearing gold hoop earrings at presentation, which were near the black patches. Certain topical products (eg, makeup, sunscreens [especially those containing zinc oxide or titanium oxide], toothpaste) can abrade metal, causing it to deposit on the skin and absorb light.³ The black discoloration is not permanent and can be prevented by avoiding contact between inciting products and metals.² No further diagnostic testing is necessary, and the patches will self-resolve if contact with the product is avoided.

Our patient noted that she wore a physical sunscreen daily, but the black patches were present only when she wore the gold hoop earrings. Given this history and physical examination findings in the office, it was suspected she had black dermographism due to her gold earrings and topical sunscreen. The patient was advised to avoid wearing the gold earrings.

Black dermographism is a misnomer because it is not a true urticarial reaction but rather a false dermographism; therefore, patients will not experience pruritus or erythema.¹ True dermographism is an inducible urticarial eruption from pressure or trauma to the skin. The clinical appearance is notable for erythematous wheals in the shape of the external force applied.⁴ Two other types of false dermographism include white dermographism, which occurs secondary to allergic contact dermatitis, and yellow dermographism, which is caused by bile deposits on the skin.⁴

Additional diagnoses were able to be ruled out for the following reasons: cutaneous mastocytosis can manifest with red-brown maculopapular lesions often accompanied by the Darier sign, which includes swelling, pruritus, and erythema but was not present in our patient.⁴ Allergic contact dermatitis manifests as a delayed eczematous reaction around 48 to 72 hours after exposure to an allergen. Our patient’s lesions formed while wearing gold earrings but did not manifest with a hypersensitivity reaction. Of note, symptomatic dermographism has been reported to mimic latex allergy.⁵ Ecchymosis may appear as erythematous, violaceous, or yellow-green patches depending on the stage but develops due to leakage from broken blood vessels secondary to trauma, which was not reported in our patient. Type I hypersensitivity reactions can occur minutes to hours after exposure to an allergen but typically manifest with a wheal-and-flare presentation.

Black dermographism from gold earrings can mimic concerning skin disorders or poor hygiene, causing unnecessary anxiety. Understanding that it is a harmless reaction between gold and certain topical products can reassure patients and prevent unnecessary testing or treatments.

THE DIAGNOSIS: Black Dermographism

Black dermographism is characterized by asymptomatic black discoloration on the skin caused by contact with various metals, most commonly gold but also silver, nickel, zinc, lead, and aluminum.¹ These metallic particles have a black appearance as they do not reflect light.² Our patient was wearing gold hoop earrings at presentation, which were near the black patches. Certain topical products (eg, makeup, sunscreens [especially those containing zinc oxide or titanium oxide], toothpaste) can abrade metal, causing it to deposit on the skin and absorb light.³ The black discoloration is not permanent and can be prevented by avoiding contact between inciting products and metals.² No further diagnostic testing is necessary, and the patches will self-resolve if contact with the product is avoided.

Our patient noted that she wore a physical sunscreen daily, but the black patches were present only when she wore the gold hoop earrings. Given this history and physical examination findings in the office, it was suspected she had black dermographism due to her gold earrings and topical sunscreen. The patient was advised to avoid wearing the gold earrings.

Black dermographism is a misnomer because it is not a true urticarial reaction but rather a false dermographism; therefore, patients will not experience pruritus or erythema.¹ True dermographism is an inducible urticarial eruption from pressure or trauma to the skin. The clinical appearance is notable for erythematous wheals in the shape of the external force applied.⁴ Two other types of false dermographism include white dermographism, which occurs secondary to allergic contact dermatitis, and yellow dermographism, which is caused by bile deposits on the skin.⁴

Additional diagnoses were able to be ruled out for the following reasons: cutaneous mastocytosis can manifest with red-brown maculopapular lesions often accompanied by the Darier sign, which includes swelling, pruritus, and erythema but was not present in our patient.⁴ Allergic contact dermatitis manifests as a delayed eczematous reaction around 48 to 72 hours after exposure to an allergen. Our patient’s lesions formed while wearing gold earrings but did not manifest with a hypersensitivity reaction. Of note, symptomatic dermographism has been reported to mimic latex allergy.⁵ Ecchymosis may appear as erythematous, violaceous, or yellow-green patches depending on the stage but develops due to leakage from broken blood vessels secondary to trauma, which was not reported in our patient. Type I hypersensitivity reactions can occur minutes to hours after exposure to an allergen but typically manifest with a wheal-and-flare presentation.

Black dermographism from gold earrings can mimic concerning skin disorders or poor hygiene, causing unnecessary anxiety. Understanding that it is a harmless reaction between gold and certain topical products can reassure patients and prevent unnecessary testing or treatments.

THE DIAGNOSIS: Black Dermographism

Black dermographism is characterized by asymptomatic black discoloration on the skin caused by contact with various metals, most commonly gold but also silver, nickel, zinc, lead, and aluminum.¹ These metallic particles have a black appearance as they do not reflect light.² Our patient was wearing gold hoop earrings at presentation, which were near the black patches. Certain topical products (eg, makeup, sunscreens [especially those containing zinc oxide or titanium oxide], toothpaste) can abrade metal, causing it to deposit on the skin and absorb light.³ The black discoloration is not permanent and can be prevented by avoiding contact between inciting products and metals.² No further diagnostic testing is necessary, and the patches will self-resolve if contact with the product is avoided.

Our patient noted that she wore a physical sunscreen daily, but the black patches were present only when she wore the gold hoop earrings. Given this history and physical examination findings in the office, it was suspected she had black dermographism due to her gold earrings and topical sunscreen. The patient was advised to avoid wearing the gold earrings.

Black dermographism is a misnomer because it is not a true urticarial reaction but rather a false dermographism; therefore, patients will not experience pruritus or erythema.¹ True dermographism is an inducible urticarial eruption from pressure or trauma to the skin. The clinical appearance is notable for erythematous wheals in the shape of the external force applied.⁴ Two other types of false dermographism include white dermographism, which occurs secondary to allergic contact dermatitis, and yellow dermographism, which is caused by bile deposits on the skin.⁴

Additional diagnoses were able to be ruled out for the following reasons: cutaneous mastocytosis can manifest with red-brown maculopapular lesions often accompanied by the Darier sign, which includes swelling, pruritus, and erythema but was not present in our patient.⁴ Allergic contact dermatitis manifests as a delayed eczematous reaction around 48 to 72 hours after exposure to an allergen. Our patient’s lesions formed while wearing gold earrings but did not manifest with a hypersensitivity reaction. Of note, symptomatic dermographism has been reported to mimic latex allergy.⁵ Ecchymosis may appear as erythematous, violaceous, or yellow-green patches depending on the stage but develops due to leakage from broken blood vessels secondary to trauma, which was not reported in our patient. Type I hypersensitivity reactions can occur minutes to hours after exposure to an allergen but typically manifest with a wheal-and-flare presentation.

Black dermographism from gold earrings can mimic concerning skin disorders or poor hygiene, causing unnecessary anxiety. Understanding that it is a harmless reaction between gold and certain topical products can reassure patients and prevent unnecessary testing or treatments.

THE DIAGNOSIS: Disseminate and Recurrent Infundibulofolliculitis

Histopathology demonstrated a lymphocyte-predominant infundibular infiltrate with mild spongiosis and lymphocytic exocytosis; a mild, superficial perivascular infiltrate also was present. The surrounding skin was largely normal with no notable papillomatosis, acanthosis, or hyperkeratosis (Figure 1). The clinical presentation and histopathologic findings led to the diagnosis of disseminate and recurrent infundibulofolliculitis (DRIF). The patient was started on a 2-week course of once-daily ammonium lactate lotion 12% and urea cream 40% and twice-daily triamcinolone ointment 0.1%. The patient was instructed to take a 1-week break before this regimen was repeated. Isotretinoin 0.5 mg/kg/d for 2 to 4 months was considered and will be an option if there is no improvement at follow-up.

Disseminate and recurrent infundibulofolliculitis is a rare noninfectious folliculitis that initially was described by Hitch and Lund¹ in 1968. Males of African descent are most commonly affected by DRIF, but the condition is not limited to this population.^2,3 It manifests as asymptomatic, flesh-colored, monomorphic, follicular papules distributed on the trunk and proximal extremities. Pustules can be present, and hair may be seen protruding from them. As the name suggests, DRIF is associated with histopathologic changes that are prominent at the infundibulum of hair follicles.^3,4 Disseminate and recurrent infundibulofolliculitis can persist for months to years because it often is resistant to treatment. Treatments include topical monotherapies such as corticosteroids, calcineurin inhibitors, or retinoids; combination topical treatments; antibiotics; and isotretinoin.² Recurrent remission and exacerbation occurs in many patients.³

The classic manifestations of DRIF, including follicular, monomorphic, flesh-colored papules distributed on the neck, trunk, and proximal upper extremities, were seen in our patient (Figure 2). These findings along with the skin biopsy identifying a lymphocytic infundibular infiltrate led to the diagnosis of DRIF. The papules associated with DRIF can be recurrent or chronic. The lesions in this patient were chronic and persistent.

Despite limited evidence, it has been suggested that DRIF may be a manifestation of atopic dermatitis in patients with darker skin tones. In our case, the patient had a history of childhood eczema. Other hypotheses have proposed that DRIF could be a nonspecific reaction to a currently unknown antigen. A causative infectious agent has not been identified, although the search continues. There is speculation that DRIF could be an overt expression of normal follicular prominence, but the presence of occasional pustules and lymphocyte- predominant infundibular infiltrate negates that.³

Confluent and reticulated papillomatosis was included in the differential for our patient and manifests as asymptomatic hyperpigmented papules and plaques frequently occurring on the upper trunk, neck, and axilla; however, these lesions have a peripheral netlike configuration, as the name suggests. Additionally, this condition is thought to have an infectious component (Dietzia papillomatosis) and responds to antibiotic treatment.⁵ Follicular eczema also was high in the differential diagnosis but usually is seasonal and pruritic, and histopathology typically shows the features of spongiotic dermatitis. It also would respond well to topical steroids.⁶ Another condition high on the differential was juxtaclavicular beaded lines, which also manifests as flesh-colored follicular papules distributed on the upper trunk; however, histopathology usually shows features of hyperplastic pilosebaceous units along with spongiosis and exocytosis.⁷ Pityrosporum folliculitis initially was considered, but the patient only endorsed occasional pruritus. Additionally, no fungal elements were observed.

Currently, there are no definitive treatments for DRIF. The topical treatments available include midpotency corticosteroids, tretinoin, calcineurin inhibitors, 12% lactic acid, and 20% to 40% urea. The systemic therapies are high-dose oral vitamin A (100,000 IU/d), isotretinoin, and psoralen plus UVA.^8-10

THE DIAGNOSIS: Disseminate and Recurrent Infundibulofolliculitis

Histopathology demonstrated a lymphocyte-predominant infundibular infiltrate with mild spongiosis and lymphocytic exocytosis; a mild, superficial perivascular infiltrate also was present. The surrounding skin was largely normal with no notable papillomatosis, acanthosis, or hyperkeratosis (Figure 1). The clinical presentation and histopathologic findings led to the diagnosis of disseminate and recurrent infundibulofolliculitis (DRIF). The patient was started on a 2-week course of once-daily ammonium lactate lotion 12% and urea cream 40% and twice-daily triamcinolone ointment 0.1%. The patient was instructed to take a 1-week break before this regimen was repeated. Isotretinoin 0.5 mg/kg/d for 2 to 4 months was considered and will be an option if there is no improvement at follow-up.

Disseminate and recurrent infundibulofolliculitis is a rare noninfectious folliculitis that initially was described by Hitch and Lund¹ in 1968. Males of African descent are most commonly affected by DRIF, but the condition is not limited to this population.^2,3 It manifests as asymptomatic, flesh-colored, monomorphic, follicular papules distributed on the trunk and proximal extremities. Pustules can be present, and hair may be seen protruding from them. As the name suggests, DRIF is associated with histopathologic changes that are prominent at the infundibulum of hair follicles.^3,4 Disseminate and recurrent infundibulofolliculitis can persist for months to years because it often is resistant to treatment. Treatments include topical monotherapies such as corticosteroids, calcineurin inhibitors, or retinoids; combination topical treatments; antibiotics; and isotretinoin.² Recurrent remission and exacerbation occurs in many patients.³

The classic manifestations of DRIF, including follicular, monomorphic, flesh-colored papules distributed on the neck, trunk, and proximal upper extremities, were seen in our patient (Figure 2). These findings along with the skin biopsy identifying a lymphocytic infundibular infiltrate led to the diagnosis of DRIF. The papules associated with DRIF can be recurrent or chronic. The lesions in this patient were chronic and persistent.

Despite limited evidence, it has been suggested that DRIF may be a manifestation of atopic dermatitis in patients with darker skin tones. In our case, the patient had a history of childhood eczema. Other hypotheses have proposed that DRIF could be a nonspecific reaction to a currently unknown antigen. A causative infectious agent has not been identified, although the search continues. There is speculation that DRIF could be an overt expression of normal follicular prominence, but the presence of occasional pustules and lymphocyte- predominant infundibular infiltrate negates that.³

Confluent and reticulated papillomatosis was included in the differential for our patient and manifests as asymptomatic hyperpigmented papules and plaques frequently occurring on the upper trunk, neck, and axilla; however, these lesions have a peripheral netlike configuration, as the name suggests. Additionally, this condition is thought to have an infectious component (Dietzia papillomatosis) and responds to antibiotic treatment.⁵ Follicular eczema also was high in the differential diagnosis but usually is seasonal and pruritic, and histopathology typically shows the features of spongiotic dermatitis. It also would respond well to topical steroids.⁶ Another condition high on the differential was juxtaclavicular beaded lines, which also manifests as flesh-colored follicular papules distributed on the upper trunk; however, histopathology usually shows features of hyperplastic pilosebaceous units along with spongiosis and exocytosis.⁷ Pityrosporum folliculitis initially was considered, but the patient only endorsed occasional pruritus. Additionally, no fungal elements were observed.

Currently, there are no definitive treatments for DRIF. The topical treatments available include midpotency corticosteroids, tretinoin, calcineurin inhibitors, 12% lactic acid, and 20% to 40% urea. The systemic therapies are high-dose oral vitamin A (100,000 IU/d), isotretinoin, and psoralen plus UVA.^8-10

THE DIAGNOSIS: Disseminate and Recurrent Infundibulofolliculitis

Histopathology demonstrated a lymphocyte-predominant infundibular infiltrate with mild spongiosis and lymphocytic exocytosis; a mild, superficial perivascular infiltrate also was present. The surrounding skin was largely normal with no notable papillomatosis, acanthosis, or hyperkeratosis (Figure 1). The clinical presentation and histopathologic findings led to the diagnosis of disseminate and recurrent infundibulofolliculitis (DRIF). The patient was started on a 2-week course of once-daily ammonium lactate lotion 12% and urea cream 40% and twice-daily triamcinolone ointment 0.1%. The patient was instructed to take a 1-week break before this regimen was repeated. Isotretinoin 0.5 mg/kg/d for 2 to 4 months was considered and will be an option if there is no improvement at follow-up.

Disseminate and recurrent infundibulofolliculitis is a rare noninfectious folliculitis that initially was described by Hitch and Lund¹ in 1968. Males of African descent are most commonly affected by DRIF, but the condition is not limited to this population.^2,3 It manifests as asymptomatic, flesh-colored, monomorphic, follicular papules distributed on the trunk and proximal extremities. Pustules can be present, and hair may be seen protruding from them. As the name suggests, DRIF is associated with histopathologic changes that are prominent at the infundibulum of hair follicles.^3,4 Disseminate and recurrent infundibulofolliculitis can persist for months to years because it often is resistant to treatment. Treatments include topical monotherapies such as corticosteroids, calcineurin inhibitors, or retinoids; combination topical treatments; antibiotics; and isotretinoin.² Recurrent remission and exacerbation occurs in many patients.³

The classic manifestations of DRIF, including follicular, monomorphic, flesh-colored papules distributed on the neck, trunk, and proximal upper extremities, were seen in our patient (Figure 2). These findings along with the skin biopsy identifying a lymphocytic infundibular infiltrate led to the diagnosis of DRIF. The papules associated with DRIF can be recurrent or chronic. The lesions in this patient were chronic and persistent.

Despite limited evidence, it has been suggested that DRIF may be a manifestation of atopic dermatitis in patients with darker skin tones. In our case, the patient had a history of childhood eczema. Other hypotheses have proposed that DRIF could be a nonspecific reaction to a currently unknown antigen. A causative infectious agent has not been identified, although the search continues. There is speculation that DRIF could be an overt expression of normal follicular prominence, but the presence of occasional pustules and lymphocyte- predominant infundibular infiltrate negates that.³

Confluent and reticulated papillomatosis was included in the differential for our patient and manifests as asymptomatic hyperpigmented papules and plaques frequently occurring on the upper trunk, neck, and axilla; however, these lesions have a peripheral netlike configuration, as the name suggests. Additionally, this condition is thought to have an infectious component (Dietzia papillomatosis) and responds to antibiotic treatment.⁵ Follicular eczema also was high in the differential diagnosis but usually is seasonal and pruritic, and histopathology typically shows the features of spongiotic dermatitis. It also would respond well to topical steroids.⁶ Another condition high on the differential was juxtaclavicular beaded lines, which also manifests as flesh-colored follicular papules distributed on the upper trunk; however, histopathology usually shows features of hyperplastic pilosebaceous units along with spongiosis and exocytosis.⁷ Pityrosporum folliculitis initially was considered, but the patient only endorsed occasional pruritus. Additionally, no fungal elements were observed.

Currently, there are no definitive treatments for DRIF. The topical treatments available include midpotency corticosteroids, tretinoin, calcineurin inhibitors, 12% lactic acid, and 20% to 40% urea. The systemic therapies are high-dose oral vitamin A (100,000 IU/d), isotretinoin, and psoralen plus UVA.^8-10

THE DIAGNOSIS: Terra Firma-Forme Dermatosis

During clinical examination, a 70% alcohol swab was utilized to gently rub several of the lesions, which were successfully removed. This confirmed a diagnosis of terra firma-forme dermatosis (TFFD)(also known as Duncan’s dirty dermatosis). The patient’s mother was counseled about the diagnosis and was instructed on how to use alcohol pads to remove the remaining lesions. Three days later, after several treatment sessions at home, the mother reported complete resolution of the lesions with no residual pigmentary changes, ulceration, or scarring (Figures 1 and 2).

Terra firma-forme dermatosis was first described in 1987 in a 12-year-old girl with hyperpigmented plaques on the neck that cleared when rubbing alcohol was applied before biopsy.^1,2 The term terra firma is Latin for “firm land” (or essentially “dirt”) in reference to what often is described as a characteristically “dirty” clinical appearance.² Terra firmaforme dermatosis can manifest anywhere on the body but shows a predilection for the neck, arms and legs, axillae, inguinal region, and umbilicus.³ Lesions typically are described as asymptomatic, smooth, well-circumscribed, reticular papules or patches that are brown or black. Terra firma-forme dermatosis also may demonstrate secondary features such as hyperkeratotic, scaly, velvety, or verrucous plaques and nodules.³

The etiology of this condition is theorized to be a result of abnormal or delayed keratinization and prolonged keratinocyte adhesion.^3,4 There are limited epidemiologic data, but TFFD has shown a predominance in children younger than 18 years (average age of onset, 10 years) with no known predilection for sex or race and no recognized pattern of inheritance.^3-5

Histopathology typically demonstrates epidermal atrophy, hyperkeratosis, and often a component of trapping and compaction of melanin, sebum, microorganisms, and environmental debris.⁵

Management of TFFD is straightforward and generally consists of rubbing with 70% isopropyl alcohol to remove the lesions. For more adherent lesions or for extensive involvement, other keratolytics such as salicylic acid or alpha-hydroxy acids may be used.⁵ For TFFD manifesting in infants and young children, widespread involvement, or lesions involving the face or genitals, a urea-based keratolytic with or without a topical anti-inflammatory is suggested.⁵ Other treatment options include other alpha-hydroxy acids, topical retinoids, and nonpolar solvents such as acetone or CO2 laser for recalcitrant cases.^4,5 Fortunately, most TFFD lesions respond well to conservative therapies, with recurrence reported only in 6.3% (5/79) of patients in one study.³

Dermatosis neglecta is clinically similar to TFFD and often is considered on the same spectrum of disease⁶; however, this entity is associated with decreased bathing or limited hygiene, which could be related to child or elder abuse/neglect or comorbid psychiatric disorders. These conditions can be distinguished by attempting to remove the lesions using soap and water; lesions of dermatosis neglecta will clear, whereas those of TFFD will not.

Metastatic melanoma in pediatric patients has a polymorphous appearance and may or may not be pigmented. Lesions often may be associated with lymphadenopathy of the draining lymph node basins, and nodules and lesions may be firm on palpation.⁷ Linear configurations of metastatic melanoma may represent a satellite or in-transit metastasis. Fortunately, melanoma is extraordinarily rare in children, with an estimated incidence of 2.1 per million for individuals younger than 20 years.⁸

Acanthosis nigricans is characterized by velvety plaques most commonly affecting the posterior neck, axillae, and flexor extremities. These lesions commonly are associated with obesity and insulin resistance but occasionally can be associated with underlying malignancy. In the latter association, acanthosis nigricans lesions tend to manifest more abruptly, often are pruritic, and can involve the mucous membranes. Fortunately, acanthosis nigricans related to malignancy in the pediatric population is rare.⁹

Epidermal nevi may exhibit clinical similarities to TFFD, particularly in lesions with brown/black pigment or with a reticulated or verrucous appearance; however, epidermal nevi often are congenital or manifest within the first few years of life. They commonly are distributed over the lines of Blaschko and have a linear appearance; they also enlarge and thicken as the patient ages.¹⁰

Black-dot tinea capitis, a classic manifestation of endothrix infection, manifests as alopecia with broken hairs and is most commonly caused by Tinea tonsurans.¹¹ The black dots refer to the appearance of the infected hair shafts, which have been weakened and broken off at the follicular ostia. As such, lesions typically are monomorphic and may be interspersed with uninvolved hair shafts. There often is associated scale and a lack of inflammation.^11,12

Additional differential diagnoses to consider include seborrheic keratoses and confluent and reticulated papillomatosis. Further workup (eg, potassium hydroxide preparation of skin scrapings or skin biopsy) may help elucidate the diagnosis.⁵ A simple and cost-effective initial diagnostic tool involves wiping suspicious lesions with a 70% isopropyl alcohol pad to confirm this diagnosis.

THE DIAGNOSIS: Terra Firma-Forme Dermatosis

During clinical examination, a 70% alcohol swab was utilized to gently rub several of the lesions, which were successfully removed. This confirmed a diagnosis of terra firma-forme dermatosis (TFFD)(also known as Duncan’s dirty dermatosis). The patient’s mother was counseled about the diagnosis and was instructed on how to use alcohol pads to remove the remaining lesions. Three days later, after several treatment sessions at home, the mother reported complete resolution of the lesions with no residual pigmentary changes, ulceration, or scarring (Figures 1 and 2).

Terra firma-forme dermatosis was first described in 1987 in a 12-year-old girl with hyperpigmented plaques on the neck that cleared when rubbing alcohol was applied before biopsy.^1,2 The term terra firma is Latin for “firm land” (or essentially “dirt”) in reference to what often is described as a characteristically “dirty” clinical appearance.² Terra firmaforme dermatosis can manifest anywhere on the body but shows a predilection for the neck, arms and legs, axillae, inguinal region, and umbilicus.³ Lesions typically are described as asymptomatic, smooth, well-circumscribed, reticular papules or patches that are brown or black. Terra firma-forme dermatosis also may demonstrate secondary features such as hyperkeratotic, scaly, velvety, or verrucous plaques and nodules.³

The etiology of this condition is theorized to be a result of abnormal or delayed keratinization and prolonged keratinocyte adhesion.^3,4 There are limited epidemiologic data, but TFFD has shown a predominance in children younger than 18 years (average age of onset, 10 years) with no known predilection for sex or race and no recognized pattern of inheritance.^3-5

Histopathology typically demonstrates epidermal atrophy, hyperkeratosis, and often a component of trapping and compaction of melanin, sebum, microorganisms, and environmental debris.⁵

Management of TFFD is straightforward and generally consists of rubbing with 70% isopropyl alcohol to remove the lesions. For more adherent lesions or for extensive involvement, other keratolytics such as salicylic acid or alpha-hydroxy acids may be used.⁵ For TFFD manifesting in infants and young children, widespread involvement, or lesions involving the face or genitals, a urea-based keratolytic with or without a topical anti-inflammatory is suggested.⁵ Other treatment options include other alpha-hydroxy acids, topical retinoids, and nonpolar solvents such as acetone or CO2 laser for recalcitrant cases.^4,5 Fortunately, most TFFD lesions respond well to conservative therapies, with recurrence reported only in 6.3% (5/79) of patients in one study.³

Dermatosis neglecta is clinically similar to TFFD and often is considered on the same spectrum of disease⁶; however, this entity is associated with decreased bathing or limited hygiene, which could be related to child or elder abuse/neglect or comorbid psychiatric disorders. These conditions can be distinguished by attempting to remove the lesions using soap and water; lesions of dermatosis neglecta will clear, whereas those of TFFD will not.

Metastatic melanoma in pediatric patients has a polymorphous appearance and may or may not be pigmented. Lesions often may be associated with lymphadenopathy of the draining lymph node basins, and nodules and lesions may be firm on palpation.⁷ Linear configurations of metastatic melanoma may represent a satellite or in-transit metastasis. Fortunately, melanoma is extraordinarily rare in children, with an estimated incidence of 2.1 per million for individuals younger than 20 years.⁸

Acanthosis nigricans is characterized by velvety plaques most commonly affecting the posterior neck, axillae, and flexor extremities. These lesions commonly are associated with obesity and insulin resistance but occasionally can be associated with underlying malignancy. In the latter association, acanthosis nigricans lesions tend to manifest more abruptly, often are pruritic, and can involve the mucous membranes. Fortunately, acanthosis nigricans related to malignancy in the pediatric population is rare.⁹

Epidermal nevi may exhibit clinical similarities to TFFD, particularly in lesions with brown/black pigment or with a reticulated or verrucous appearance; however, epidermal nevi often are congenital or manifest within the first few years of life. They commonly are distributed over the lines of Blaschko and have a linear appearance; they also enlarge and thicken as the patient ages.¹⁰

Black-dot tinea capitis, a classic manifestation of endothrix infection, manifests as alopecia with broken hairs and is most commonly caused by Tinea tonsurans.¹¹ The black dots refer to the appearance of the infected hair shafts, which have been weakened and broken off at the follicular ostia. As such, lesions typically are monomorphic and may be interspersed with uninvolved hair shafts. There often is associated scale and a lack of inflammation.^11,12

Additional differential diagnoses to consider include seborrheic keratoses and confluent and reticulated papillomatosis. Further workup (eg, potassium hydroxide preparation of skin scrapings or skin biopsy) may help elucidate the diagnosis.⁵ A simple and cost-effective initial diagnostic tool involves wiping suspicious lesions with a 70% isopropyl alcohol pad to confirm this diagnosis.

THE DIAGNOSIS: Terra Firma-Forme Dermatosis

During clinical examination, a 70% alcohol swab was utilized to gently rub several of the lesions, which were successfully removed. This confirmed a diagnosis of terra firma-forme dermatosis (TFFD)(also known as Duncan’s dirty dermatosis). The patient’s mother was counseled about the diagnosis and was instructed on how to use alcohol pads to remove the remaining lesions. Three days later, after several treatment sessions at home, the mother reported complete resolution of the lesions with no residual pigmentary changes, ulceration, or scarring (Figures 1 and 2).

Terra firma-forme dermatosis was first described in 1987 in a 12-year-old girl with hyperpigmented plaques on the neck that cleared when rubbing alcohol was applied before biopsy.^1,2 The term terra firma is Latin for “firm land” (or essentially “dirt”) in reference to what often is described as a characteristically “dirty” clinical appearance.² Terra firmaforme dermatosis can manifest anywhere on the body but shows a predilection for the neck, arms and legs, axillae, inguinal region, and umbilicus.³ Lesions typically are described as asymptomatic, smooth, well-circumscribed, reticular papules or patches that are brown or black. Terra firma-forme dermatosis also may demonstrate secondary features such as hyperkeratotic, scaly, velvety, or verrucous plaques and nodules.³

The etiology of this condition is theorized to be a result of abnormal or delayed keratinization and prolonged keratinocyte adhesion.^3,4 There are limited epidemiologic data, but TFFD has shown a predominance in children younger than 18 years (average age of onset, 10 years) with no known predilection for sex or race and no recognized pattern of inheritance.^3-5

Histopathology typically demonstrates epidermal atrophy, hyperkeratosis, and often a component of trapping and compaction of melanin, sebum, microorganisms, and environmental debris.⁵

Management of TFFD is straightforward and generally consists of rubbing with 70% isopropyl alcohol to remove the lesions. For more adherent lesions or for extensive involvement, other keratolytics such as salicylic acid or alpha-hydroxy acids may be used.⁵ For TFFD manifesting in infants and young children, widespread involvement, or lesions involving the face or genitals, a urea-based keratolytic with or without a topical anti-inflammatory is suggested.⁵ Other treatment options include other alpha-hydroxy acids, topical retinoids, and nonpolar solvents such as acetone or CO2 laser for recalcitrant cases.^4,5 Fortunately, most TFFD lesions respond well to conservative therapies, with recurrence reported only in 6.3% (5/79) of patients in one study.³

Dermatosis neglecta is clinically similar to TFFD and often is considered on the same spectrum of disease⁶; however, this entity is associated with decreased bathing or limited hygiene, which could be related to child or elder abuse/neglect or comorbid psychiatric disorders. These conditions can be distinguished by attempting to remove the lesions using soap and water; lesions of dermatosis neglecta will clear, whereas those of TFFD will not.

Metastatic melanoma in pediatric patients has a polymorphous appearance and may or may not be pigmented. Lesions often may be associated with lymphadenopathy of the draining lymph node basins, and nodules and lesions may be firm on palpation.⁷ Linear configurations of metastatic melanoma may represent a satellite or in-transit metastasis. Fortunately, melanoma is extraordinarily rare in children, with an estimated incidence of 2.1 per million for individuals younger than 20 years.⁸

Acanthosis nigricans is characterized by velvety plaques most commonly affecting the posterior neck, axillae, and flexor extremities. These lesions commonly are associated with obesity and insulin resistance but occasionally can be associated with underlying malignancy. In the latter association, acanthosis nigricans lesions tend to manifest more abruptly, often are pruritic, and can involve the mucous membranes. Fortunately, acanthosis nigricans related to malignancy in the pediatric population is rare.⁹

Epidermal nevi may exhibit clinical similarities to TFFD, particularly in lesions with brown/black pigment or with a reticulated or verrucous appearance; however, epidermal nevi often are congenital or manifest within the first few years of life. They commonly are distributed over the lines of Blaschko and have a linear appearance; they also enlarge and thicken as the patient ages.¹⁰

Black-dot tinea capitis, a classic manifestation of endothrix infection, manifests as alopecia with broken hairs and is most commonly caused by Tinea tonsurans.¹¹ The black dots refer to the appearance of the infected hair shafts, which have been weakened and broken off at the follicular ostia. As such, lesions typically are monomorphic and may be interspersed with uninvolved hair shafts. There often is associated scale and a lack of inflammation.^11,12

Additional differential diagnoses to consider include seborrheic keratoses and confluent and reticulated papillomatosis. Further workup (eg, potassium hydroxide preparation of skin scrapings or skin biopsy) may help elucidate the diagnosis.⁵ A simple and cost-effective initial diagnostic tool involves wiping suspicious lesions with a 70% isopropyl alcohol pad to confirm this diagnosis.

THE DIAGNOSIS: Follicular Mucinosis

Histologic examination of the hematoxylin and eosin–stained sections of the biopsy revealed an overall moderately dense, perivascular, and perifollicular lymphocytic infiltrate with follicular intraepidermal mucin (Figure). Immunohistochemical staining showed that the lymphocytic infiltrate was predominantly CD4+ over CD8+, with moderate loss of CD7 and absence of CD20 expression. Positive T-cell receptor (TCR) gene rearrangements were detected for both TCRγ and TCRΒ. The clinical features along with the histopathologic findings suggested a diagnosis of follicular mucinosis (FM) with concern in the differential for folliculotropic mycosis fungoides.

Follicular mucinosis, also known as alopecia mucinosa, is an uncommon inflammatory disorder characterized by follicular degeneration due to the accumulation of mucin within the pilosebaceous unit.¹ This condition manifests clinically as indurated plaques and/or follicular papules most often on the face, neck, and scalp.² It is further categorized as primary vs secondary FM. Primary idiopathic FM, which can further be subdivided into acute or chronic, tends to follow a more benign course, whereas secondary FM usually is associated with underlying inflammatory or neoplastic conditions, most commonly mycosis fungoides, a cutaneous T-cell lymphoma.^1,2 In cases of secondary FM, treatment of the underlying cause often leads to resolution of symptoms. Regular follow-up is warranted in either classification.^1,3

The initial differential diagnosis for this patient included contact dermatitis associated with mask use, with possible underlying seborrheic dermatitis or rosacea; however, the rash persisted and worsened after treatment with topical triamcinolone and ketoconazole. After the diagnosis of FM was made, the patient was started on topical betamethasone and tacrolimus with good response.

A referral to hematology/oncology revealed that the patient had primary FM and possible stage 1A folliculotropic mycosis fungoides with limited skin involvement (<10% body surface area). On physical examination, no palpable cervical or axillary lymphadenopathy were noted. Flow cytometry for lymphoma was negative with no lymphoid or blast population detected. Laboratory workup and positron emission tomography/computed tomography were unremarkable. The patient had rapid improvement with a more potent topical steroid but also was given tacrolimus ointment 0.1% for residual findings. His disease remained stable without progression at 1-year follow-up.

Contact dermatitis typically manifests as an eczematous eruption that appears on an anatomic location that was exposed to or came into contact with allergens or irritants.⁴ Contact dermatitis was less likely in our patient due to the lack of acute or subacute spongiosis and lymphocyte exocytosis. Rosacea is a chronic inflammatory dermatosis that presents as recurrent episodes of flushing or transient erythema, persistent erythema, phyphymatous changes, papules, pustules, and telangiectasia⁵; however, rosacea was less likely in our patient due to the histopathologic and immunohistochemical findings that were suggestive of FM on punch biopsy. Cutaneous lupus generally is associated with photosensitivity and manifests as erythema over the malar eminences and bridge of the nose with sparing of the nasolabial folds.⁶ Seborrheic dermatitis manifests as erythematous macules or patches with scale and associated pruritis on the scalp, eyebrows, eyelids, and nasolabial folds.⁷ This condition was less likely in our patient due to the persistence and worsening of the facial erythematous dermatitis despite the use of ketoconazole cream as well as no evidence of spongiosis, shoulder parakeratosis, vascular changes, or presence of microorganisms such as Malassezia species.

Due to the relatively rare nature of this condition as well as a wide variety of other more common etiologies for an erythematous dermatitis of the cheeks, the diagnosis of FM may be delayed or missed entirely. Physicians must have a high index of suspicion to diagnose properly and biopsy if necessary. This photoquiz serves as an important reminder to physicians to keep uncommon diseases on their differential, especially when the patient’s symptoms do not respond to treatment.

THE DIAGNOSIS: Follicular Mucinosis

Histologic examination of the hematoxylin and eosin–stained sections of the biopsy revealed an overall moderately dense, perivascular, and perifollicular lymphocytic infiltrate with follicular intraepidermal mucin (Figure). Immunohistochemical staining showed that the lymphocytic infiltrate was predominantly CD4+ over CD8+, with moderate loss of CD7 and absence of CD20 expression. Positive T-cell receptor (TCR) gene rearrangements were detected for both TCRγ and TCRΒ. The clinical features along with the histopathologic findings suggested a diagnosis of follicular mucinosis (FM) with concern in the differential for folliculotropic mycosis fungoides.

Follicular mucinosis, also known as alopecia mucinosa, is an uncommon inflammatory disorder characterized by follicular degeneration due to the accumulation of mucin within the pilosebaceous unit.¹ This condition manifests clinically as indurated plaques and/or follicular papules most often on the face, neck, and scalp.² It is further categorized as primary vs secondary FM. Primary idiopathic FM, which can further be subdivided into acute or chronic, tends to follow a more benign course, whereas secondary FM usually is associated with underlying inflammatory or neoplastic conditions, most commonly mycosis fungoides, a cutaneous T-cell lymphoma.^1,2 In cases of secondary FM, treatment of the underlying cause often leads to resolution of symptoms. Regular follow-up is warranted in either classification.^1,3

The initial differential diagnosis for this patient included contact dermatitis associated with mask use, with possible underlying seborrheic dermatitis or rosacea; however, the rash persisted and worsened after treatment with topical triamcinolone and ketoconazole. After the diagnosis of FM was made, the patient was started on topical betamethasone and tacrolimus with good response.

A referral to hematology/oncology revealed that the patient had primary FM and possible stage 1A folliculotropic mycosis fungoides with limited skin involvement (<10% body surface area). On physical examination, no palpable cervical or axillary lymphadenopathy were noted. Flow cytometry for lymphoma was negative with no lymphoid or blast population detected. Laboratory workup and positron emission tomography/computed tomography were unremarkable. The patient had rapid improvement with a more potent topical steroid but also was given tacrolimus ointment 0.1% for residual findings. His disease remained stable without progression at 1-year follow-up.

Contact dermatitis typically manifests as an eczematous eruption that appears on an anatomic location that was exposed to or came into contact with allergens or irritants.⁴ Contact dermatitis was less likely in our patient due to the lack of acute or subacute spongiosis and lymphocyte exocytosis. Rosacea is a chronic inflammatory dermatosis that presents as recurrent episodes of flushing or transient erythema, persistent erythema, phyphymatous changes, papules, pustules, and telangiectasia⁵; however, rosacea was less likely in our patient due to the histopathologic and immunohistochemical findings that were suggestive of FM on punch biopsy. Cutaneous lupus generally is associated with photosensitivity and manifests as erythema over the malar eminences and bridge of the nose with sparing of the nasolabial folds.⁶ Seborrheic dermatitis manifests as erythematous macules or patches with scale and associated pruritis on the scalp, eyebrows, eyelids, and nasolabial folds.⁷ This condition was less likely in our patient due to the persistence and worsening of the facial erythematous dermatitis despite the use of ketoconazole cream as well as no evidence of spongiosis, shoulder parakeratosis, vascular changes, or presence of microorganisms such as Malassezia species.

Due to the relatively rare nature of this condition as well as a wide variety of other more common etiologies for an erythematous dermatitis of the cheeks, the diagnosis of FM may be delayed or missed entirely. Physicians must have a high index of suspicion to diagnose properly and biopsy if necessary. This photoquiz serves as an important reminder to physicians to keep uncommon diseases on their differential, especially when the patient’s symptoms do not respond to treatment.

THE DIAGNOSIS: Follicular Mucinosis

Histologic examination of the hematoxylin and eosin–stained sections of the biopsy revealed an overall moderately dense, perivascular, and perifollicular lymphocytic infiltrate with follicular intraepidermal mucin (Figure). Immunohistochemical staining showed that the lymphocytic infiltrate was predominantly CD4+ over CD8+, with moderate loss of CD7 and absence of CD20 expression. Positive T-cell receptor (TCR) gene rearrangements were detected for both TCRγ and TCRΒ. The clinical features along with the histopathologic findings suggested a diagnosis of follicular mucinosis (FM) with concern in the differential for folliculotropic mycosis fungoides.

Follicular mucinosis, also known as alopecia mucinosa, is an uncommon inflammatory disorder characterized by follicular degeneration due to the accumulation of mucin within the pilosebaceous unit.¹ This condition manifests clinically as indurated plaques and/or follicular papules most often on the face, neck, and scalp.² It is further categorized as primary vs secondary FM. Primary idiopathic FM, which can further be subdivided into acute or chronic, tends to follow a more benign course, whereas secondary FM usually is associated with underlying inflammatory or neoplastic conditions, most commonly mycosis fungoides, a cutaneous T-cell lymphoma.^1,2 In cases of secondary FM, treatment of the underlying cause often leads to resolution of symptoms. Regular follow-up is warranted in either classification.^1,3

The initial differential diagnosis for this patient included contact dermatitis associated with mask use, with possible underlying seborrheic dermatitis or rosacea; however, the rash persisted and worsened after treatment with topical triamcinolone and ketoconazole. After the diagnosis of FM was made, the patient was started on topical betamethasone and tacrolimus with good response.

A referral to hematology/oncology revealed that the patient had primary FM and possible stage 1A folliculotropic mycosis fungoides with limited skin involvement (<10% body surface area). On physical examination, no palpable cervical or axillary lymphadenopathy were noted. Flow cytometry for lymphoma was negative with no lymphoid or blast population detected. Laboratory workup and positron emission tomography/computed tomography were unremarkable. The patient had rapid improvement with a more potent topical steroid but also was given tacrolimus ointment 0.1% for residual findings. His disease remained stable without progression at 1-year follow-up.

Contact dermatitis typically manifests as an eczematous eruption that appears on an anatomic location that was exposed to or came into contact with allergens or irritants.⁴ Contact dermatitis was less likely in our patient due to the lack of acute or subacute spongiosis and lymphocyte exocytosis. Rosacea is a chronic inflammatory dermatosis that presents as recurrent episodes of flushing or transient erythema, persistent erythema, phyphymatous changes, papules, pustules, and telangiectasia⁵; however, rosacea was less likely in our patient due to the histopathologic and immunohistochemical findings that were suggestive of FM on punch biopsy. Cutaneous lupus generally is associated with photosensitivity and manifests as erythema over the malar eminences and bridge of the nose with sparing of the nasolabial folds.⁶ Seborrheic dermatitis manifests as erythematous macules or patches with scale and associated pruritis on the scalp, eyebrows, eyelids, and nasolabial folds.⁷ This condition was less likely in our patient due to the persistence and worsening of the facial erythematous dermatitis despite the use of ketoconazole cream as well as no evidence of spongiosis, shoulder parakeratosis, vascular changes, or presence of microorganisms such as Malassezia species.

Due to the relatively rare nature of this condition as well as a wide variety of other more common etiologies for an erythematous dermatitis of the cheeks, the diagnosis of FM may be delayed or missed entirely. Physicians must have a high index of suspicion to diagnose properly and biopsy if necessary. This photoquiz serves as an important reminder to physicians to keep uncommon diseases on their differential, especially when the patient’s symptoms do not respond to treatment.

THE DIAGNOSIS: Neutrophilic Dermatosis of the Dorsal Hands

Histopathology showed a unilocular pustule with a dense neutrophilic infiltrate of the superficial dermis. Minimal vascular alterations also were observed. These findings were consistent with a diagnosis of neutrophilic dermatosis of the dorsal hands (NDDH). Our patient was treated successfully with systemic corticosteroids (1 mg/kg/d) with rapid improvement after 10 days of treatment.

Neutrophilic dermatosis of the dorsal hands is an evolving disease concept that was first described as pustular vasculitis by Strutton et al¹ in 1995. Galaria et al² subsequently identified NDDH as a clinical entity associating tender erythematous plaques, pustules, bullae, and/or ulcers on the dorsal hands with histologic features of Sweet syndrome (SS). After reviewing 9 cases of NDDH—all of which demonstrated clinical, laboratory, and histologic characteristics of SS—Walling et al³ concluded that NDDH was best understood as a distributional variant of SS.

Our patient presented with vascular alterations described as a reactive response to the neutrophilic infiltration. The presence of vasculitis in SS and NDDH biopsies is considered as an occasional epiphenomenon and should not rule out the diagnosis of NDDH.³ A literature review of 123 cases of NDDH revealed the presence of vasculitis in 36 (29.5%) patients.⁴ With regard to other clinical findings, it has been suggested that an increased white blood cell count and elevated C-reactive protein level, as was seen in our patient, may be observed in NDDH, albeit less frequently than in classical SS.⁴

While palmar involvement of NDDH is considered rare, the recent review of 123 cases of NDDH identified palmar lesions in 5 patients (4.1%).⁴ Earlier reviews had identified 12 historical cases.⁵ Palmar manifestations of NDDH have been shown to be associated with erythematous nonulcerated lesions (as opposed to the classical ulcerative or pustular plaques) and a lower association with hematologic malignancies.⁵

In our patient’s case, dyshidrosis was excluded due to the presence of painful ulcerative plaques rather than pruritic, deep-seated vesicles. Pustular psoriasis typically manifests with sterile pustules on the palms and soles; however, the rapid onset of ulcerative, necrotic plaques and substantial edema are more specific to NDDH. Poststreptococcal pustulosis generally follows a streptococcal infection and lacks the violaceous undermined borders seen in NDDH. Reactive arthritis manifests with hyperkeratotic plaques and is associated with the clinical triad of urethritis, conjunctivitis, and arthritis, which were absent in our patient.

The histologic differential diagnosis of NDDH includes infection, pyoderma gangrenosum, bowel-associated dermatosis-arthritis syndrome, rheumatoid neutrophilic dermatitis, and erythema elevatum diutinum^3,4; however, these conditions typically manifest with distinct clinical features that allow for differentiation, despite histologic similarities. The wide histologic spectrum of neutrophilic dermatosis may contribute to variable clinical manifestations and an evolving disease concept, as the classification of NDDH has changed from a primary vasculitis to a variant of SS. However, this evolution does not affect the appropriate management, as they all have shown good response to corticosteroid treatment.^4,6

THE DIAGNOSIS: Neutrophilic Dermatosis of the Dorsal Hands

Histopathology showed a unilocular pustule with a dense neutrophilic infiltrate of the superficial dermis. Minimal vascular alterations also were observed. These findings were consistent with a diagnosis of neutrophilic dermatosis of the dorsal hands (NDDH). Our patient was treated successfully with systemic corticosteroids (1 mg/kg/d) with rapid improvement after 10 days of treatment.

Neutrophilic dermatosis of the dorsal hands is an evolving disease concept that was first described as pustular vasculitis by Strutton et al¹ in 1995. Galaria et al² subsequently identified NDDH as a clinical entity associating tender erythematous plaques, pustules, bullae, and/or ulcers on the dorsal hands with histologic features of Sweet syndrome (SS). After reviewing 9 cases of NDDH—all of which demonstrated clinical, laboratory, and histologic characteristics of SS—Walling et al³ concluded that NDDH was best understood as a distributional variant of SS.

Our patient presented with vascular alterations described as a reactive response to the neutrophilic infiltration. The presence of vasculitis in SS and NDDH biopsies is considered as an occasional epiphenomenon and should not rule out the diagnosis of NDDH.³ A literature review of 123 cases of NDDH revealed the presence of vasculitis in 36 (29.5%) patients.⁴ With regard to other clinical findings, it has been suggested that an increased white blood cell count and elevated C-reactive protein level, as was seen in our patient, may be observed in NDDH, albeit less frequently than in classical SS.⁴

While palmar involvement of NDDH is considered rare, the recent review of 123 cases of NDDH identified palmar lesions in 5 patients (4.1%).⁴ Earlier reviews had identified 12 historical cases.⁵ Palmar manifestations of NDDH have been shown to be associated with erythematous nonulcerated lesions (as opposed to the classical ulcerative or pustular plaques) and a lower association with hematologic malignancies.⁵

In our patient’s case, dyshidrosis was excluded due to the presence of painful ulcerative plaques rather than pruritic, deep-seated vesicles. Pustular psoriasis typically manifests with sterile pustules on the palms and soles; however, the rapid onset of ulcerative, necrotic plaques and substantial edema are more specific to NDDH. Poststreptococcal pustulosis generally follows a streptococcal infection and lacks the violaceous undermined borders seen in NDDH. Reactive arthritis manifests with hyperkeratotic plaques and is associated with the clinical triad of urethritis, conjunctivitis, and arthritis, which were absent in our patient.

The histologic differential diagnosis of NDDH includes infection, pyoderma gangrenosum, bowel-associated dermatosis-arthritis syndrome, rheumatoid neutrophilic dermatitis, and erythema elevatum diutinum^3,4; however, these conditions typically manifest with distinct clinical features that allow for differentiation, despite histologic similarities. The wide histologic spectrum of neutrophilic dermatosis may contribute to variable clinical manifestations and an evolving disease concept, as the classification of NDDH has changed from a primary vasculitis to a variant of SS. However, this evolution does not affect the appropriate management, as they all have shown good response to corticosteroid treatment.^4,6

THE DIAGNOSIS: Neutrophilic Dermatosis of the Dorsal Hands

Histopathology showed a unilocular pustule with a dense neutrophilic infiltrate of the superficial dermis. Minimal vascular alterations also were observed. These findings were consistent with a diagnosis of neutrophilic dermatosis of the dorsal hands (NDDH). Our patient was treated successfully with systemic corticosteroids (1 mg/kg/d) with rapid improvement after 10 days of treatment.

Neutrophilic dermatosis of the dorsal hands is an evolving disease concept that was first described as pustular vasculitis by Strutton et al¹ in 1995. Galaria et al² subsequently identified NDDH as a clinical entity associating tender erythematous plaques, pustules, bullae, and/or ulcers on the dorsal hands with histologic features of Sweet syndrome (SS). After reviewing 9 cases of NDDH—all of which demonstrated clinical, laboratory, and histologic characteristics of SS—Walling et al³ concluded that NDDH was best understood as a distributional variant of SS.

Our patient presented with vascular alterations described as a reactive response to the neutrophilic infiltration. The presence of vasculitis in SS and NDDH biopsies is considered as an occasional epiphenomenon and should not rule out the diagnosis of NDDH.³ A literature review of 123 cases of NDDH revealed the presence of vasculitis in 36 (29.5%) patients.⁴ With regard to other clinical findings, it has been suggested that an increased white blood cell count and elevated C-reactive protein level, as was seen in our patient, may be observed in NDDH, albeit less frequently than in classical SS.⁴

While palmar involvement of NDDH is considered rare, the recent review of 123 cases of NDDH identified palmar lesions in 5 patients (4.1%).⁴ Earlier reviews had identified 12 historical cases.⁵ Palmar manifestations of NDDH have been shown to be associated with erythematous nonulcerated lesions (as opposed to the classical ulcerative or pustular plaques) and a lower association with hematologic malignancies.⁵

In our patient’s case, dyshidrosis was excluded due to the presence of painful ulcerative plaques rather than pruritic, deep-seated vesicles. Pustular psoriasis typically manifests with sterile pustules on the palms and soles; however, the rapid onset of ulcerative, necrotic plaques and substantial edema are more specific to NDDH. Poststreptococcal pustulosis generally follows a streptococcal infection and lacks the violaceous undermined borders seen in NDDH. Reactive arthritis manifests with hyperkeratotic plaques and is associated with the clinical triad of urethritis, conjunctivitis, and arthritis, which were absent in our patient.

The histologic differential diagnosis of NDDH includes infection, pyoderma gangrenosum, bowel-associated dermatosis-arthritis syndrome, rheumatoid neutrophilic dermatitis, and erythema elevatum diutinum^3,4; however, these conditions typically manifest with distinct clinical features that allow for differentiation, despite histologic similarities. The wide histologic spectrum of neutrophilic dermatosis may contribute to variable clinical manifestations and an evolving disease concept, as the classification of NDDH has changed from a primary vasculitis to a variant of SS. However, this evolution does not affect the appropriate management, as they all have shown good response to corticosteroid treatment.^4,6

THE DIAGNOSIS: Cutaneous Leishmaniasis

The biopsy results revealed amastigotes at the periphery of parasitized histiocytes, consistent with a diagnosis of cutaneous leishmaniasis. Polymerase chain reaction analysis revealed Leishmania guyanensis species complex, which includes both L guyanensis and Leishmania panamensis. In this case of disseminated cutaneous leishmaniasis (Figure 1), our patient received a prolonged course of systemic therapy with oral miltefosine 50 mg 3 times daily. At the most recent follow-up appointment, she showed ongoing resolution of ulcerations, subcutaneous plaques, and lymphadenopathy on the trunk and face, but development of subcutaneous nodules continued on the arms and legs. At the next follow-up, physical examination revealed that the lesions slowly started to fade.

Leishmania species are parasites transmitted by bites of female sand flies, which belong to the genera Phlebotomus (Old World, Eastern Hemisphere) and Lutzomyia (New World, Western Hemisphere) genera.¹ Leishmania species have a complex life cycle, propagating within human macrophages, ultimately leading to cutaneous, mucocutaneous, and visceral disease manifestations.² Cutaneous leishmaniasis manifests classically as scattered, painless, slow-healing ulcers.³ A biopsy taken from the edge of a cutaneous ulcer for hematoxylin and eosin processing is recommended for initial diagnosis, and subsequent polymerase chain reaction of the sample is required for speciation, which guides therapeutic options.^4,5 Classic hematoxylin and eosin and Giemsa stain findings include amastigotes lining the edges of parasitized histiocytes (Figure 2).

Systemic treatment options include sodium stibogluconate, amphotericin B, pentamidine, paromomycin, miltefosine, and azole antifungals.^2,5 Geography often plays a critical role in selecting treatment options due to resistance rates of individual Leishmania species; for example, paromomycin compounds are more effective for cutaneous disease caused by Leishmania major than Leishmania tropica. Miltefosine is not effective for treating Leishmania braziliensis which can be acquired outside Guatemala, and higher doses of amphotericin B are recommended for visceral disease from East Africa.^2,5 In patients with cutaneous leishmaniasis caused by L guyanensis, miltefosine remains a first-line option due to its oral formulation and long half-life within organisms, though there is a risk for teratogenicity.² Amphotericin B remains the most effective treatment for visceral leishmaniasis and can be used off label to treat mucocutaneous disease or when cutaneous disease is refractory to other treatment options.³

Given the potential of L guyanensis to progress to mucocutaneous disease, monitoring for mucosal involvement should be performed at regular intervals for 6 months to 1 year.² Treatment may be considered efficacious if no new skin lesions occur after 4 to 6 weeks of therapy; existing skin lesions should be re-epithelializing and reduced by 50% in size, with most cutaneous disease adequately controlled after 3 months of therapy.²

THE DIAGNOSIS: Cutaneous Leishmaniasis

The biopsy results revealed amastigotes at the periphery of parasitized histiocytes, consistent with a diagnosis of cutaneous leishmaniasis. Polymerase chain reaction analysis revealed Leishmania guyanensis species complex, which includes both L guyanensis and Leishmania panamensis. In this case of disseminated cutaneous leishmaniasis (Figure 1), our patient received a prolonged course of systemic therapy with oral miltefosine 50 mg 3 times daily. At the most recent follow-up appointment, she showed ongoing resolution of ulcerations, subcutaneous plaques, and lymphadenopathy on the trunk and face, but development of subcutaneous nodules continued on the arms and legs. At the next follow-up, physical examination revealed that the lesions slowly started to fade.

Leishmania species are parasites transmitted by bites of female sand flies, which belong to the genera Phlebotomus (Old World, Eastern Hemisphere) and Lutzomyia (New World, Western Hemisphere) genera.¹ Leishmania species have a complex life cycle, propagating within human macrophages, ultimately leading to cutaneous, mucocutaneous, and visceral disease manifestations.² Cutaneous leishmaniasis manifests classically as scattered, painless, slow-healing ulcers.³ A biopsy taken from the edge of a cutaneous ulcer for hematoxylin and eosin processing is recommended for initial diagnosis, and subsequent polymerase chain reaction of the sample is required for speciation, which guides therapeutic options.^4,5 Classic hematoxylin and eosin and Giemsa stain findings include amastigotes lining the edges of parasitized histiocytes (Figure 2).

Systemic treatment options include sodium stibogluconate, amphotericin B, pentamidine, paromomycin, miltefosine, and azole antifungals.^2,5 Geography often plays a critical role in selecting treatment options due to resistance rates of individual Leishmania species; for example, paromomycin compounds are more effective for cutaneous disease caused by Leishmania major than Leishmania tropica. Miltefosine is not effective for treating Leishmania braziliensis which can be acquired outside Guatemala, and higher doses of amphotericin B are recommended for visceral disease from East Africa.^2,5 In patients with cutaneous leishmaniasis caused by L guyanensis, miltefosine remains a first-line option due to its oral formulation and long half-life within organisms, though there is a risk for teratogenicity.² Amphotericin B remains the most effective treatment for visceral leishmaniasis and can be used off label to treat mucocutaneous disease or when cutaneous disease is refractory to other treatment options.³

Given the potential of L guyanensis to progress to mucocutaneous disease, monitoring for mucosal involvement should be performed at regular intervals for 6 months to 1 year.² Treatment may be considered efficacious if no new skin lesions occur after 4 to 6 weeks of therapy; existing skin lesions should be re-epithelializing and reduced by 50% in size, with most cutaneous disease adequately controlled after 3 months of therapy.²

THE DIAGNOSIS: Cutaneous Leishmaniasis

The biopsy results revealed amastigotes at the periphery of parasitized histiocytes, consistent with a diagnosis of cutaneous leishmaniasis. Polymerase chain reaction analysis revealed Leishmania guyanensis species complex, which includes both L guyanensis and Leishmania panamensis. In this case of disseminated cutaneous leishmaniasis (Figure 1), our patient received a prolonged course of systemic therapy with oral miltefosine 50 mg 3 times daily. At the most recent follow-up appointment, she showed ongoing resolution of ulcerations, subcutaneous plaques, and lymphadenopathy on the trunk and face, but development of subcutaneous nodules continued on the arms and legs. At the next follow-up, physical examination revealed that the lesions slowly started to fade.

Leishmania species are parasites transmitted by bites of female sand flies, which belong to the genera Phlebotomus (Old World, Eastern Hemisphere) and Lutzomyia (New World, Western Hemisphere) genera.¹ Leishmania species have a complex life cycle, propagating within human macrophages, ultimately leading to cutaneous, mucocutaneous, and visceral disease manifestations.² Cutaneous leishmaniasis manifests classically as scattered, painless, slow-healing ulcers.³ A biopsy taken from the edge of a cutaneous ulcer for hematoxylin and eosin processing is recommended for initial diagnosis, and subsequent polymerase chain reaction of the sample is required for speciation, which guides therapeutic options.^4,5 Classic hematoxylin and eosin and Giemsa stain findings include amastigotes lining the edges of parasitized histiocytes (Figure 2).

Systemic treatment options include sodium stibogluconate, amphotericin B, pentamidine, paromomycin, miltefosine, and azole antifungals.^2,5 Geography often plays a critical role in selecting treatment options due to resistance rates of individual Leishmania species; for example, paromomycin compounds are more effective for cutaneous disease caused by Leishmania major than Leishmania tropica. Miltefosine is not effective for treating Leishmania braziliensis which can be acquired outside Guatemala, and higher doses of amphotericin B are recommended for visceral disease from East Africa.^2,5 In patients with cutaneous leishmaniasis caused by L guyanensis, miltefosine remains a first-line option due to its oral formulation and long half-life within organisms, though there is a risk for teratogenicity.² Amphotericin B remains the most effective treatment for visceral leishmaniasis and can be used off label to treat mucocutaneous disease or when cutaneous disease is refractory to other treatment options.³

Given the potential of L guyanensis to progress to mucocutaneous disease, monitoring for mucosal involvement should be performed at regular intervals for 6 months to 1 year.² Treatment may be considered efficacious if no new skin lesions occur after 4 to 6 weeks of therapy; existing skin lesions should be re-epithelializing and reduced by 50% in size, with most cutaneous disease adequately controlled after 3 months of therapy.²

THE DIAGNOSIS: Pacemaker Extrusion

The lesion crust was easily scraped away to reveal extrusion of the permanent pacemaker (PPM) through the skin with a visible overlying gelatinous biofilm (Figure). The patient subsequently completed a 2-week course of clindamycin 300 mg 3 times daily followed by generator and lead removal, with reimplantation of the PPM into the right chest, as is the standard of care in the treatment of pacemaker extrusion.¹

Ours is the first known reported case of pacemaker extrusion referred to dermatology with a primary concern for cutaneous malignancy. Pacemaker extrusion through the skin is not common, but it is the most common complication of PPM implantation, followed by infection.¹ Pacemaker extrusion results from pressure necrosis and occurs when the PPM emerges through erythematous skin.^1,2 Pacemaker extrusions generally are diagnosed by cardiology; however, it is important for dermatologists to recognize this phenomenon and differentiate it from other cutaneous pathologies, as the morphology of skin changes related to pacemaker extrusion through the skin can mimic cutaneous malignancy or other primary skin disease, especially if the outer layer of a biofilm that forms around the PPM hardens to form a crust. Our case emphasizes the importance of removing crusts when evaluating lesions.³

THE DIAGNOSIS: Pacemaker Extrusion

The lesion crust was easily scraped away to reveal extrusion of the permanent pacemaker (PPM) through the skin with a visible overlying gelatinous biofilm (Figure). The patient subsequently completed a 2-week course of clindamycin 300 mg 3 times daily followed by generator and lead removal, with reimplantation of the PPM into the right chest, as is the standard of care in the treatment of pacemaker extrusion.¹

Ours is the first known reported case of pacemaker extrusion referred to dermatology with a primary concern for cutaneous malignancy. Pacemaker extrusion through the skin is not common, but it is the most common complication of PPM implantation, followed by infection.¹ Pacemaker extrusion results from pressure necrosis and occurs when the PPM emerges through erythematous skin.^1,2 Pacemaker extrusions generally are diagnosed by cardiology; however, it is important for dermatologists to recognize this phenomenon and differentiate it from other cutaneous pathologies, as the morphology of skin changes related to pacemaker extrusion through the skin can mimic cutaneous malignancy or other primary skin disease, especially if the outer layer of a biofilm that forms around the PPM hardens to form a crust. Our case emphasizes the importance of removing crusts when evaluating lesions.³

THE DIAGNOSIS: Pacemaker Extrusion

The lesion crust was easily scraped away to reveal extrusion of the permanent pacemaker (PPM) through the skin with a visible overlying gelatinous biofilm (Figure). The patient subsequently completed a 2-week course of clindamycin 300 mg 3 times daily followed by generator and lead removal, with reimplantation of the PPM into the right chest, as is the standard of care in the treatment of pacemaker extrusion.¹

Ours is the first known reported case of pacemaker extrusion referred to dermatology with a primary concern for cutaneous malignancy. Pacemaker extrusion through the skin is not common, but it is the most common complication of PPM implantation, followed by infection.¹ Pacemaker extrusion results from pressure necrosis and occurs when the PPM emerges through erythematous skin.^1,2 Pacemaker extrusions generally are diagnosed by cardiology; however, it is important for dermatologists to recognize this phenomenon and differentiate it from other cutaneous pathologies, as the morphology of skin changes related to pacemaker extrusion through the skin can mimic cutaneous malignancy or other primary skin disease, especially if the outer layer of a biofilm that forms around the PPM hardens to form a crust. Our case emphasizes the importance of removing crusts when evaluating lesions.³