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The Diagnosis: Nipple Adenoma (Florid Papillomatosis of the Nipple) 

Biopsy of the nodule showed florid papillary hyperplasia of the ductal epithelium within the dermis that was sharply demarcated from the background stroma (Figure, A and B). Neither cytological nor architectural atypia were evident. There was no notable necrosis (Figure C). There was a background of fibrosis whereby the glandular ductal structures assumed a somewhat irregular growth pattern within the dermis with attendant hemorrhage. The patient underwent complete excision of the lesion. No evidence of carcinoma was seen on the final pathology, and the final margins were negative. 

First described in 1923 and fully characterized in 1955, nipple adenoma (also known as florid papillomatosis of the nipple) is a benign proliferative neoplasm that originates in the lactiferous ducts of the nipple.^1,2 It most commonly affects women aged 40 to 50 years (range, 0-89 years); less than 5% of cases are reported in men.^3,4 It predominantly is unilateral, with only rare cases of bilateral papillomatosis reported. Patients often present with serous or serosanguineous discharge and an itching or burning sensation. Symptoms may worsen with the menstrual cycle.⁴ On physical examination, it presents as an ill-defined red nodule on the nipple with crusting, erosion, or erythema of the nipple surface. Although imaging generally is not used to confirm the diagnosis, mammography should be performed prior to biopsy to rule out underlying breast pathology. Dermoscopy may show linear cherry red structures or red serpiginous and annular structures.^5,6 The differential diagnosis of nipple adenoma includes Paget disease of the breast, adenomyoepithelioma, subareolar subsclerosing duct hyperplasia, syringomatous adenoma, adenosis tumor, low-grade adenosquamous carcinoma, low-grade ductal carcinoma in situ, tubular carcinoma, and sweat gland tumors.³  

Microscopic features of nipple adenoma have been categorized into 4 subtypes: sclerosing papillomatosis, papillomatosis, adenosis, and a mixed pattern.^3,7 The tumors may have keratin cysts and focal necrosis but no atypia, and the myoepithelial cell layer is retained. Nipple adenomas show a glandular proliferation in the dermis that is relatively well circumscribed with glands that vary in appearance between a simple adenosislike pattern of growth to a papillary hyperplasia and/or usual ductal hyperplasia growth pattern. A pseudoinfiltrative pattern can occur when the glandular epithelium is entrapped within stromal fibrosis; however, the myoepithelial layer is retained. Occasionally, the glandular epithelium can grow in continuity with the surface squamous epithelium of the nipple, clinically simulating Paget disease of the breast.⁸ Immunohistochemical stains, specifically p63, p40, calponin 1, h-caldesmon, cytokeratin 5/6, CD10, and α; smooth muscle actin, highlight the myoepithelial cells, while cytokeratin 7 identifies the ductal epithelium, supporting the diagnosis.⁶ In addition to biopsy and microscopic tissue examination, touch preparation cytology, curettage cytology, and fine needle aspiration techniques have been used to perform cytologic examination of the lesions, aiding in identification of the benign or malignant nature of the neoplasm.⁶ Nipple adenoma also is referred to as florid papillomatosis of the nipple, papillary adenoma, erosive adenomatosis, and subareolar duct papillomatosis.⁷ 

Although nipple adenoma is a benign tumor, up to 16.5% of affected patients had an ipsilateral or contralateral mammary carcinoma.⁹ The majority arose coincidentally but separately in the same breast, and carcinoma arose directly from the nipple adenoma in 8 cases; 3 cases were carcinomas that arose in men.¹⁰ A definitive association or causal relationship between nipple adenoma and subsequent development of breast cancer has not been identified, and the incidence of nipple adenoma in patients with a positive family history of breast cancer has not been examined. Therefore, although various treatments including cryosurgery, nipple splitting enucleation, and Mohs micrographic surgery have been proposed, complete excision remains the gold standard of therapy. Regular breast examinations and digital mammography are necessary to screen for local recurrences.  

The Diagnosis: Nipple Adenoma (Florid Papillomatosis of the Nipple) 

Biopsy of the nodule showed florid papillary hyperplasia of the ductal epithelium within the dermis that was sharply demarcated from the background stroma (Figure, A and B). Neither cytological nor architectural atypia were evident. There was no notable necrosis (Figure C). There was a background of fibrosis whereby the glandular ductal structures assumed a somewhat irregular growth pattern within the dermis with attendant hemorrhage. The patient underwent complete excision of the lesion. No evidence of carcinoma was seen on the final pathology, and the final margins were negative. 

First described in 1923 and fully characterized in 1955, nipple adenoma (also known as florid papillomatosis of the nipple) is a benign proliferative neoplasm that originates in the lactiferous ducts of the nipple.^1,2 It most commonly affects women aged 40 to 50 years (range, 0-89 years); less than 5% of cases are reported in men.^3,4 It predominantly is unilateral, with only rare cases of bilateral papillomatosis reported. Patients often present with serous or serosanguineous discharge and an itching or burning sensation. Symptoms may worsen with the menstrual cycle.⁴ On physical examination, it presents as an ill-defined red nodule on the nipple with crusting, erosion, or erythema of the nipple surface. Although imaging generally is not used to confirm the diagnosis, mammography should be performed prior to biopsy to rule out underlying breast pathology. Dermoscopy may show linear cherry red structures or red serpiginous and annular structures.^5,6 The differential diagnosis of nipple adenoma includes Paget disease of the breast, adenomyoepithelioma, subareolar subsclerosing duct hyperplasia, syringomatous adenoma, adenosis tumor, low-grade adenosquamous carcinoma, low-grade ductal carcinoma in situ, tubular carcinoma, and sweat gland tumors.³  

Microscopic features of nipple adenoma have been categorized into 4 subtypes: sclerosing papillomatosis, papillomatosis, adenosis, and a mixed pattern.^3,7 The tumors may have keratin cysts and focal necrosis but no atypia, and the myoepithelial cell layer is retained. Nipple adenomas show a glandular proliferation in the dermis that is relatively well circumscribed with glands that vary in appearance between a simple adenosislike pattern of growth to a papillary hyperplasia and/or usual ductal hyperplasia growth pattern. A pseudoinfiltrative pattern can occur when the glandular epithelium is entrapped within stromal fibrosis; however, the myoepithelial layer is retained. Occasionally, the glandular epithelium can grow in continuity with the surface squamous epithelium of the nipple, clinically simulating Paget disease of the breast.⁸ Immunohistochemical stains, specifically p63, p40, calponin 1, h-caldesmon, cytokeratin 5/6, CD10, and α; smooth muscle actin, highlight the myoepithelial cells, while cytokeratin 7 identifies the ductal epithelium, supporting the diagnosis.⁶ In addition to biopsy and microscopic tissue examination, touch preparation cytology, curettage cytology, and fine needle aspiration techniques have been used to perform cytologic examination of the lesions, aiding in identification of the benign or malignant nature of the neoplasm.⁶ Nipple adenoma also is referred to as florid papillomatosis of the nipple, papillary adenoma, erosive adenomatosis, and subareolar duct papillomatosis.⁷ 

Although nipple adenoma is a benign tumor, up to 16.5% of affected patients had an ipsilateral or contralateral mammary carcinoma.⁹ The majority arose coincidentally but separately in the same breast, and carcinoma arose directly from the nipple adenoma in 8 cases; 3 cases were carcinomas that arose in men.¹⁰ A definitive association or causal relationship between nipple adenoma and subsequent development of breast cancer has not been identified, and the incidence of nipple adenoma in patients with a positive family history of breast cancer has not been examined. Therefore, although various treatments including cryosurgery, nipple splitting enucleation, and Mohs micrographic surgery have been proposed, complete excision remains the gold standard of therapy. Regular breast examinations and digital mammography are necessary to screen for local recurrences.  

The Diagnosis: Nipple Adenoma (Florid Papillomatosis of the Nipple) 

Biopsy of the nodule showed florid papillary hyperplasia of the ductal epithelium within the dermis that was sharply demarcated from the background stroma (Figure, A and B). Neither cytological nor architectural atypia were evident. There was no notable necrosis (Figure C). There was a background of fibrosis whereby the glandular ductal structures assumed a somewhat irregular growth pattern within the dermis with attendant hemorrhage. The patient underwent complete excision of the lesion. No evidence of carcinoma was seen on the final pathology, and the final margins were negative. 

First described in 1923 and fully characterized in 1955, nipple adenoma (also known as florid papillomatosis of the nipple) is a benign proliferative neoplasm that originates in the lactiferous ducts of the nipple.^1,2 It most commonly affects women aged 40 to 50 years (range, 0-89 years); less than 5% of cases are reported in men.^3,4 It predominantly is unilateral, with only rare cases of bilateral papillomatosis reported. Patients often present with serous or serosanguineous discharge and an itching or burning sensation. Symptoms may worsen with the menstrual cycle.⁴ On physical examination, it presents as an ill-defined red nodule on the nipple with crusting, erosion, or erythema of the nipple surface. Although imaging generally is not used to confirm the diagnosis, mammography should be performed prior to biopsy to rule out underlying breast pathology. Dermoscopy may show linear cherry red structures or red serpiginous and annular structures.^5,6 The differential diagnosis of nipple adenoma includes Paget disease of the breast, adenomyoepithelioma, subareolar subsclerosing duct hyperplasia, syringomatous adenoma, adenosis tumor, low-grade adenosquamous carcinoma, low-grade ductal carcinoma in situ, tubular carcinoma, and sweat gland tumors.³  

Microscopic features of nipple adenoma have been categorized into 4 subtypes: sclerosing papillomatosis, papillomatosis, adenosis, and a mixed pattern.^3,7 The tumors may have keratin cysts and focal necrosis but no atypia, and the myoepithelial cell layer is retained. Nipple adenomas show a glandular proliferation in the dermis that is relatively well circumscribed with glands that vary in appearance between a simple adenosislike pattern of growth to a papillary hyperplasia and/or usual ductal hyperplasia growth pattern. A pseudoinfiltrative pattern can occur when the glandular epithelium is entrapped within stromal fibrosis; however, the myoepithelial layer is retained. Occasionally, the glandular epithelium can grow in continuity with the surface squamous epithelium of the nipple, clinically simulating Paget disease of the breast.⁸ Immunohistochemical stains, specifically p63, p40, calponin 1, h-caldesmon, cytokeratin 5/6, CD10, and α; smooth muscle actin, highlight the myoepithelial cells, while cytokeratin 7 identifies the ductal epithelium, supporting the diagnosis.⁶ In addition to biopsy and microscopic tissue examination, touch preparation cytology, curettage cytology, and fine needle aspiration techniques have been used to perform cytologic examination of the lesions, aiding in identification of the benign or malignant nature of the neoplasm.⁶ Nipple adenoma also is referred to as florid papillomatosis of the nipple, papillary adenoma, erosive adenomatosis, and subareolar duct papillomatosis.⁷ 

Although nipple adenoma is a benign tumor, up to 16.5% of affected patients had an ipsilateral or contralateral mammary carcinoma.⁹ The majority arose coincidentally but separately in the same breast, and carcinoma arose directly from the nipple adenoma in 8 cases; 3 cases were carcinomas that arose in men.¹⁰ A definitive association or causal relationship between nipple adenoma and subsequent development of breast cancer has not been identified, and the incidence of nipple adenoma in patients with a positive family history of breast cancer has not been examined. Therefore, although various treatments including cryosurgery, nipple splitting enucleation, and Mohs micrographic surgery have been proposed, complete excision remains the gold standard of therapy. Regular breast examinations and digital mammography are necessary to screen for local recurrences.  

The Diagnosis: Phacomatosis Cesioflammea  

Phacomatosis pigmentovascularis (PPV) encompasses a group of diseases that have a vascular nevus coupled with a pigmented nevus.¹ It is divided into 5 types: Type I is defined by the presence of a vascular malformation and epidermal nevus; type II by a vascular malformation and dermal melanosis with or without nevus anemicus; type III by a vascular malformation and nevus spilus with or without nevus anemicus; type IV by a vascular malformation, dermal melanosis, and nevus spilus with or without nevus anemicus; and type V as cutis marmorata telangiectatica congenita and dermal melanosis.¹  

Happle² proposed a descriptive classification system in 2005 that eliminated type I PPV because neither linear epidermal nevus nor Becker nevus are derived from pigmentary cells. An appended "a" denotes a subtype with isolated cutaneous findings, while "b" is associated with extracutaneous manifestations. Phacomatosis cesioflammea (type IIa/b) refers to blue-hued dermal melanocytosis and nevus flammeus. Phacomatosis spilorosea (type IIIa/b) refers to nevus spilus and rose-colored nevus flammeus. Phacomatosis cesiomarmorata (type Va/b) refers to dermal melanocytosis and cutis marmorata telangiectasia congenita. The last group (type IVa/b) is unclassifiable phacomatosis pigmentovascularis.^2,3  

Phacomatosis pigmentovascularis can be isolated to the skin or have associated extracutaneous findings, including ocular melanocytosis, seizures, or cognitive delay due to intracerebral vascular malformations. Patients also can develop limb and soft-tissue overgrowth.⁴ Phacomatosis pigmentovascularis has been found to be associated with mutations in the GNA11 and GNAQ genes. The theory behind PPV is twin spotting, resulting from a somatic mutation that leads to mosaic proliferation of 2 different cell lines.⁵ Phacomatosis pigmentovascularis can occur in isolation or can demonstrate the phenotype of Sturge-Weber syndrome or Klippel-Trenaunay syndrome. In Sturge-Weber syndrome, capillary malformations involve the face and underlying leptomeninges and cerebral cortex. Glaucoma and epilepsy also may be present. In Klippel-Trenaunay syndrome, capillary malformations involve the extremities (usually the legs) in association with varicose veins, soft-tissue hypertrophy, and skeletal overgrowth.^6-9 Tuberous sclerosis is an autosomal-dominant neurocutaneous disease in which patients develop hamartomas throughout the body, including the brain, skin, eyes, kidneys, heart, and lungs. Cutaneous manifestations include facial angiofibromas, ungual fibromas, hypomelanotic macules (ash leaf spots, confetti-like lesions), shagreen patches or connective tissue hamartomas, and fibrous plaques on the forehead. Tuberous sclerosis does not include vascular malformations.¹⁰  

Our patient was diagnosed with PPV type IIb, or phacomatosis cesioflammea. He had a large port-wine stain involving the right upper arm, back (Figure, A), and chest (Figure, B) with involvement of the bilateral conjunctivae (Figure, C). Our case is unique because our patient did not have dermal melanocytosis, only ocular melanocytosis.  

Once underlying neurologic and vascular anomalies have been ruled out, port-wine stains can be treated cosmetically. Pulsed dye laser is the gold standard therapy for capillary malformations, especially when instituted early. Follow-up with ophthalmology is advised to monitor ocular involvement. Shields et al¹¹ suggested dilated fundoscopy for patients with port-wine stains because choroidal pigmentation often is the only ocular change seen. Ocular melanocytosis can progress to pigmented glaucoma or choroidal melanoma. 

The Diagnosis: Phacomatosis Cesioflammea  

Phacomatosis pigmentovascularis (PPV) encompasses a group of diseases that have a vascular nevus coupled with a pigmented nevus.¹ It is divided into 5 types: Type I is defined by the presence of a vascular malformation and epidermal nevus; type II by a vascular malformation and dermal melanosis with or without nevus anemicus; type III by a vascular malformation and nevus spilus with or without nevus anemicus; type IV by a vascular malformation, dermal melanosis, and nevus spilus with or without nevus anemicus; and type V as cutis marmorata telangiectatica congenita and dermal melanosis.¹  

Happle² proposed a descriptive classification system in 2005 that eliminated type I PPV because neither linear epidermal nevus nor Becker nevus are derived from pigmentary cells. An appended "a" denotes a subtype with isolated cutaneous findings, while "b" is associated with extracutaneous manifestations. Phacomatosis cesioflammea (type IIa/b) refers to blue-hued dermal melanocytosis and nevus flammeus. Phacomatosis spilorosea (type IIIa/b) refers to nevus spilus and rose-colored nevus flammeus. Phacomatosis cesiomarmorata (type Va/b) refers to dermal melanocytosis and cutis marmorata telangiectasia congenita. The last group (type IVa/b) is unclassifiable phacomatosis pigmentovascularis.^2,3  

Phacomatosis pigmentovascularis can be isolated to the skin or have associated extracutaneous findings, including ocular melanocytosis, seizures, or cognitive delay due to intracerebral vascular malformations. Patients also can develop limb and soft-tissue overgrowth.⁴ Phacomatosis pigmentovascularis has been found to be associated with mutations in the GNA11 and GNAQ genes. The theory behind PPV is twin spotting, resulting from a somatic mutation that leads to mosaic proliferation of 2 different cell lines.⁵ Phacomatosis pigmentovascularis can occur in isolation or can demonstrate the phenotype of Sturge-Weber syndrome or Klippel-Trenaunay syndrome. In Sturge-Weber syndrome, capillary malformations involve the face and underlying leptomeninges and cerebral cortex. Glaucoma and epilepsy also may be present. In Klippel-Trenaunay syndrome, capillary malformations involve the extremities (usually the legs) in association with varicose veins, soft-tissue hypertrophy, and skeletal overgrowth.^6-9 Tuberous sclerosis is an autosomal-dominant neurocutaneous disease in which patients develop hamartomas throughout the body, including the brain, skin, eyes, kidneys, heart, and lungs. Cutaneous manifestations include facial angiofibromas, ungual fibromas, hypomelanotic macules (ash leaf spots, confetti-like lesions), shagreen patches or connective tissue hamartomas, and fibrous plaques on the forehead. Tuberous sclerosis does not include vascular malformations.¹⁰  

Our patient was diagnosed with PPV type IIb, or phacomatosis cesioflammea. He had a large port-wine stain involving the right upper arm, back (Figure, A), and chest (Figure, B) with involvement of the bilateral conjunctivae (Figure, C). Our case is unique because our patient did not have dermal melanocytosis, only ocular melanocytosis.  

Once underlying neurologic and vascular anomalies have been ruled out, port-wine stains can be treated cosmetically. Pulsed dye laser is the gold standard therapy for capillary malformations, especially when instituted early. Follow-up with ophthalmology is advised to monitor ocular involvement. Shields et al¹¹ suggested dilated fundoscopy for patients with port-wine stains because choroidal pigmentation often is the only ocular change seen. Ocular melanocytosis can progress to pigmented glaucoma or choroidal melanoma. 

The Diagnosis: Phacomatosis Cesioflammea  

Phacomatosis pigmentovascularis (PPV) encompasses a group of diseases that have a vascular nevus coupled with a pigmented nevus.¹ It is divided into 5 types: Type I is defined by the presence of a vascular malformation and epidermal nevus; type II by a vascular malformation and dermal melanosis with or without nevus anemicus; type III by a vascular malformation and nevus spilus with or without nevus anemicus; type IV by a vascular malformation, dermal melanosis, and nevus spilus with or without nevus anemicus; and type V as cutis marmorata telangiectatica congenita and dermal melanosis.¹  

Happle² proposed a descriptive classification system in 2005 that eliminated type I PPV because neither linear epidermal nevus nor Becker nevus are derived from pigmentary cells. An appended "a" denotes a subtype with isolated cutaneous findings, while "b" is associated with extracutaneous manifestations. Phacomatosis cesioflammea (type IIa/b) refers to blue-hued dermal melanocytosis and nevus flammeus. Phacomatosis spilorosea (type IIIa/b) refers to nevus spilus and rose-colored nevus flammeus. Phacomatosis cesiomarmorata (type Va/b) refers to dermal melanocytosis and cutis marmorata telangiectasia congenita. The last group (type IVa/b) is unclassifiable phacomatosis pigmentovascularis.^2,3  

Phacomatosis pigmentovascularis can be isolated to the skin or have associated extracutaneous findings, including ocular melanocytosis, seizures, or cognitive delay due to intracerebral vascular malformations. Patients also can develop limb and soft-tissue overgrowth.⁴ Phacomatosis pigmentovascularis has been found to be associated with mutations in the GNA11 and GNAQ genes. The theory behind PPV is twin spotting, resulting from a somatic mutation that leads to mosaic proliferation of 2 different cell lines.⁵ Phacomatosis pigmentovascularis can occur in isolation or can demonstrate the phenotype of Sturge-Weber syndrome or Klippel-Trenaunay syndrome. In Sturge-Weber syndrome, capillary malformations involve the face and underlying leptomeninges and cerebral cortex. Glaucoma and epilepsy also may be present. In Klippel-Trenaunay syndrome, capillary malformations involve the extremities (usually the legs) in association with varicose veins, soft-tissue hypertrophy, and skeletal overgrowth.^6-9 Tuberous sclerosis is an autosomal-dominant neurocutaneous disease in which patients develop hamartomas throughout the body, including the brain, skin, eyes, kidneys, heart, and lungs. Cutaneous manifestations include facial angiofibromas, ungual fibromas, hypomelanotic macules (ash leaf spots, confetti-like lesions), shagreen patches or connective tissue hamartomas, and fibrous plaques on the forehead. Tuberous sclerosis does not include vascular malformations.¹⁰  

Our patient was diagnosed with PPV type IIb, or phacomatosis cesioflammea. He had a large port-wine stain involving the right upper arm, back (Figure, A), and chest (Figure, B) with involvement of the bilateral conjunctivae (Figure, C). Our case is unique because our patient did not have dermal melanocytosis, only ocular melanocytosis.  

Once underlying neurologic and vascular anomalies have been ruled out, port-wine stains can be treated cosmetically. Pulsed dye laser is the gold standard therapy for capillary malformations, especially when instituted early. Follow-up with ophthalmology is advised to monitor ocular involvement. Shields et al¹¹ suggested dilated fundoscopy for patients with port-wine stains because choroidal pigmentation often is the only ocular change seen. Ocular melanocytosis can progress to pigmented glaucoma or choroidal melanoma. 

The Diagnosis: Granulosis Rubra Nasi 

A history of prominent nasal sweating was later elicited and the patient was subsequently diagnosed with granulosis rubra nasi. She was instructed to continue daily use of topical pimecrolimus with the addition of topical atropine, resulting in complete resolution of the eruption at 6-week follow-up (Figure, A). She was then maintained on topical atropine monotherapy, only noting recurrence with cessation of the atropine (Figure, B).  

Other successful treatment regimens of granulosis rubra nasi include injection of botulinum toxin into the nose,¹ monotherapy with topical tacrolimus,² topical indomethacin, steroids, and cryotherapy, among other modalities.¹ Topical atropine and pimecrolimus were selected as first-line agents for treating our pediatric patient due to tolerability and their anti-inflammatory and anticholinergic properties.  

Granulosis rubra nasi is a form of focal hyperhidrosis that presents as erythematous papules, pustules, and vesicles of the midface, especially the nose.3 It is a fairly rare condition that can mimic many other common clinical entities, including comedonal acne, nevus comedonicus, periorificial dermatitis, and tinea faciei, but is resistant to treatments aimed at these disorders. It was first described as a "peculiar disease of the skin of the nose in children" in a case report by Jadassohn⁴ in 1901. It is most common in children aged 7 to 12 years and typically resolves at puberty; adults rarely are affected. Although the etiology has not yet been elucidated, autosomal-dominant transmission has been described, and the cutaneous changes are hypothesized to be secondary to hyperhidrosis.⁵ This postulation is further corroborated by a case report of a pheochromocytoma-associated granulosis rubra nasi that resolved with surgical excision of the pheochromocytoma.⁶ It is not uncommon for patients to have concomitant palmoplantar hyperhidrosis and acrocyanosis.⁵ Histopathologic examination is not necessary for diagnosis, but when performed, it discloses a mononuclear cellular infiltrate surrounding eccrine sweat ducts, blood vessels, and lymphatics without other abnormalities of the epidermis or pilosebaceous unit.^1-3,7 
 

The Diagnosis: Granulosis Rubra Nasi 

A history of prominent nasal sweating was later elicited and the patient was subsequently diagnosed with granulosis rubra nasi. She was instructed to continue daily use of topical pimecrolimus with the addition of topical atropine, resulting in complete resolution of the eruption at 6-week follow-up (Figure, A). She was then maintained on topical atropine monotherapy, only noting recurrence with cessation of the atropine (Figure, B).  

Other successful treatment regimens of granulosis rubra nasi include injection of botulinum toxin into the nose,¹ monotherapy with topical tacrolimus,² topical indomethacin, steroids, and cryotherapy, among other modalities.¹ Topical atropine and pimecrolimus were selected as first-line agents for treating our pediatric patient due to tolerability and their anti-inflammatory and anticholinergic properties.  

Granulosis rubra nasi is a form of focal hyperhidrosis that presents as erythematous papules, pustules, and vesicles of the midface, especially the nose.3 It is a fairly rare condition that can mimic many other common clinical entities, including comedonal acne, nevus comedonicus, periorificial dermatitis, and tinea faciei, but is resistant to treatments aimed at these disorders. It was first described as a "peculiar disease of the skin of the nose in children" in a case report by Jadassohn⁴ in 1901. It is most common in children aged 7 to 12 years and typically resolves at puberty; adults rarely are affected. Although the etiology has not yet been elucidated, autosomal-dominant transmission has been described, and the cutaneous changes are hypothesized to be secondary to hyperhidrosis.⁵ This postulation is further corroborated by a case report of a pheochromocytoma-associated granulosis rubra nasi that resolved with surgical excision of the pheochromocytoma.⁶ It is not uncommon for patients to have concomitant palmoplantar hyperhidrosis and acrocyanosis.⁵ Histopathologic examination is not necessary for diagnosis, but when performed, it discloses a mononuclear cellular infiltrate surrounding eccrine sweat ducts, blood vessels, and lymphatics without other abnormalities of the epidermis or pilosebaceous unit.^1-3,7 
 

The Diagnosis: Granulosis Rubra Nasi 

A history of prominent nasal sweating was later elicited and the patient was subsequently diagnosed with granulosis rubra nasi. She was instructed to continue daily use of topical pimecrolimus with the addition of topical atropine, resulting in complete resolution of the eruption at 6-week follow-up (Figure, A). She was then maintained on topical atropine monotherapy, only noting recurrence with cessation of the atropine (Figure, B).  

Other successful treatment regimens of granulosis rubra nasi include injection of botulinum toxin into the nose,¹ monotherapy with topical tacrolimus,² topical indomethacin, steroids, and cryotherapy, among other modalities.¹ Topical atropine and pimecrolimus were selected as first-line agents for treating our pediatric patient due to tolerability and their anti-inflammatory and anticholinergic properties.  

Granulosis rubra nasi is a form of focal hyperhidrosis that presents as erythematous papules, pustules, and vesicles of the midface, especially the nose.3 It is a fairly rare condition that can mimic many other common clinical entities, including comedonal acne, nevus comedonicus, periorificial dermatitis, and tinea faciei, but is resistant to treatments aimed at these disorders. It was first described as a "peculiar disease of the skin of the nose in children" in a case report by Jadassohn⁴ in 1901. It is most common in children aged 7 to 12 years and typically resolves at puberty; adults rarely are affected. Although the etiology has not yet been elucidated, autosomal-dominant transmission has been described, and the cutaneous changes are hypothesized to be secondary to hyperhidrosis.⁵ This postulation is further corroborated by a case report of a pheochromocytoma-associated granulosis rubra nasi that resolved with surgical excision of the pheochromocytoma.⁶ It is not uncommon for patients to have concomitant palmoplantar hyperhidrosis and acrocyanosis.⁵ Histopathologic examination is not necessary for diagnosis, but when performed, it discloses a mononuclear cellular infiltrate surrounding eccrine sweat ducts, blood vessels, and lymphatics without other abnormalities of the epidermis or pilosebaceous unit.^1-3,7 
 

The Diagnosis: Nodular Kaposi Sarcoma 

Epidemic Kaposi sarcoma (KS) primarily affects patients with human immunodeficiency virus (HIV) infection. Kaposi sarcoma can appear as brown, red, or blue-black macules, plaques, patches, nodules, or tumors, and it often is observed as multifocal cutaneous lesions located on the head, neck, and upper aspects of the trunk in a fulminant manner. Kaposi sarcoma portends a poor prognosis and is an AIDS-defining malignancy.^1-3 Importantly, antiretroviral therapy does not preclude its consideration in those without AIDS-defining CD4 cell counts and undetectable HIV viremia presenting with cutaneous manifestations.^2,3 A retrospective review by Daly et al⁴ reported KS lesions in patients with CD4 lymphocyte counts greater than 300 cells/µL, most of whom were antiretroviral therapy-naïve patients. Also, those with higher CD4 counts tended to have a solitary KS lesion at presentation, while those with CD4 counts less than 300 cells/µL tended to present with multiple foci.⁴ Epidemic KS lesions are clinically indistinguishable from other common cutaneous conditions in the differential diagnosis of KS, necessitating biopsy for histopathologic examination. Light microscopy findings help to delineate the diagnosis of KS. Immunohistochemical staining to the latent nuclear antigen 1 of human herpesvirus 8 (HHV-8) confirms the KS diagnosis.^5,6 Our patient's presentation as a solitary acral lesion was atypical for KS.  

Light microscopy of our patient's biopsy demonstrated a large tumor on the acral surface of the right hand. Dermal collections of basophilic spindled cells clustered with small slitlike vascular spaces with abundant erythrocyte extravasation and numerous large ectatic vessels at the periphery were seen (Figure, A). At higher magnification, interlaced bundles of spindle cells with slitlike vessels with scattered lymphocytes and plasma cells were seen (Figure, B). An immunohistochemical stain for HHV-8 was positive and largely confined to spindle cells (Figure, C). These findings confirmed KS and met AIDS-defining criteria. Awareness of these histopathologic features is key in differentiating KS from other conditions in the differential diagnosis.  

The patient's history of late latent syphilis coinfected with HIV and persistently elevated rapid plasma reagin that was recalcitrant to therapy placed an atypical nodular presentation within reason for the differential diagnosis. Deviations from the typical papulosquamous presentation with acral involvement in an immunocompromised patient mandates a consideration for syphilis with an atypical presentation. Atypical presentations include nodular, annular, pustular, lues maligna, frambesiform, corymbose, and photosensitive distributions.^7,8 Notably, coinfection with HIV modifies the clinical presentation, serology, and efficacy of treatment.^7-10 Atypical presentations are more common in coinfected HIV-positive patients, mandating a high degree of suspicion. Nodular secondary syphilis and the noduloulcerative form (lues maligna) often spare the palmar and plantar surfaces, and patients often have constitutional symptoms accompanying the cutaneous eruptions. In questionable cases, a biopsy lends clarification. Light microscopy on hematoxylin and eosin (H&E) staining may display acanthosis, superficial and deep perivascular swelling, plasma, histiocyte infiltrates, dermoepidermal junction changes, mixed patterns, epidermal hyperplasia, and dermal vascular thickening.^7-9,11 Spirochetes may be observed on Warthin-Starry stain; however, artifact obscuration from melanin granules and reticular fibers or paucity of organisms can make identification difficult. Immunohistochemical staining may prove useful when H&E stains are atypical or have a paucity of organisms or plasma cells or when silver stains have artifactual obscuration.⁹ Our patient's solitary palmar lesion without constitutional symptoms made an atypical nodular secondary syphilis presentation less likely. Ultimately, the histopathologic findings were consistent with KS.  

Bacillary angiomatosis (BA) is caused by Bartonella species and results in vascular proliferation with cutaneous manifestation. It frequently is observed in patients with HIV or other immunosuppressive conditions as well as patients with exposure to mammals or their vectors. Protean cutaneous manifestations and distributions of BA exist. The number of lesions can be singular to thousands. Solitary superficial pyogenic granuloma-like lesions can be clinically indistinguishable from both KS and pyogenic granuloma (PG). Superficial lesions often begin as red, violaceous, or flesh-colored papules that hemorrhage easily with trauma. The morphology of the papule can progress to be exophytic with dome-shaped or ulcerative surface features and is rubbery on palpation.¹² Biopsy is required to differentiate BA from KS. Bacillary angiomatosis on light microscopy with H&E shows protuberant, lobulated, round vessels with plump endothelial cells with or without necrosis. A neutrophil infiltrate in close proximity to bacilli may be noted. Warthin-Starry stain demonstrates numerous bacilli juxtaposed to these endothelial cells. The lack of immunohistochemical staining for HHV-8 also differentiates BA from KS.^12,13  

Pyogenic granuloma is resultant from proliferation of endothelial cells with a lobular architecture. Pyogenic granulomas are benign, rapidly progressive, acquired lesions presenting in the skin and mucous membranes. Pyogenic granuloma often presents as a single painless papule or nodule with a glistening red-violaceous color that occasionally appears with a perilesional collarette. The lesions are friable and easily hemorrhage. Pyogenic granuloma has been associated with local skin trauma and estrogen hormones. Histopathologic examination of PG assists with differentiation from other nodular lesions. Light microscopy with standard H&E staining demonstrates a network of capillaries arranged into a lobule surrounded by a fibrous matrix. Endothelial cells appear round and protrude into the vascular lamina. Mitotic activity is increased. Lack of findings on Warthin-Starry stain assists with differentiating PG from BA, while the microscopy architecture and immunohistochemical staining differentiates PG from KS.^6,13,14 

Squamous cell carcinoma (SCC) is the primary malignant cancer of the hand. The dorsal aspect of the hand is the most common location; SCC less commonly is located on the palmar surface, fingers, nail bed, or intertriginous areas.^15-17 Chakrabarti et al¹⁶ found that these lesions were invasive SCC when located on the palmar surface. Morphologically, SCC takes an exophytic papular, nodular, or scaly appearance with a red to flesh-colored appearance and poor demarcation of the borders. Progression to large ulcerated or secondarily infected lesions also can occur. The inflammatory reaction may cause tenderness to palpation and hemorrhage with trauma. Histopathologic examination of invasive SCC reveals atypical keratinocytes violating the basement membrane and abundant cytoplasm. Our patient's clinical presentation placed invasive SCC low on the differential diagnosis, and the histopathologic and immunohistochemical results eliminated SCC as the diagnosis. 

The Diagnosis: Nodular Kaposi Sarcoma 

Epidemic Kaposi sarcoma (KS) primarily affects patients with human immunodeficiency virus (HIV) infection. Kaposi sarcoma can appear as brown, red, or blue-black macules, plaques, patches, nodules, or tumors, and it often is observed as multifocal cutaneous lesions located on the head, neck, and upper aspects of the trunk in a fulminant manner. Kaposi sarcoma portends a poor prognosis and is an AIDS-defining malignancy.^1-3 Importantly, antiretroviral therapy does not preclude its consideration in those without AIDS-defining CD4 cell counts and undetectable HIV viremia presenting with cutaneous manifestations.^2,3 A retrospective review by Daly et al⁴ reported KS lesions in patients with CD4 lymphocyte counts greater than 300 cells/µL, most of whom were antiretroviral therapy-naïve patients. Also, those with higher CD4 counts tended to have a solitary KS lesion at presentation, while those with CD4 counts less than 300 cells/µL tended to present with multiple foci.⁴ Epidemic KS lesions are clinically indistinguishable from other common cutaneous conditions in the differential diagnosis of KS, necessitating biopsy for histopathologic examination. Light microscopy findings help to delineate the diagnosis of KS. Immunohistochemical staining to the latent nuclear antigen 1 of human herpesvirus 8 (HHV-8) confirms the KS diagnosis.^5,6 Our patient's presentation as a solitary acral lesion was atypical for KS.  

Light microscopy of our patient's biopsy demonstrated a large tumor on the acral surface of the right hand. Dermal collections of basophilic spindled cells clustered with small slitlike vascular spaces with abundant erythrocyte extravasation and numerous large ectatic vessels at the periphery were seen (Figure, A). At higher magnification, interlaced bundles of spindle cells with slitlike vessels with scattered lymphocytes and plasma cells were seen (Figure, B). An immunohistochemical stain for HHV-8 was positive and largely confined to spindle cells (Figure, C). These findings confirmed KS and met AIDS-defining criteria. Awareness of these histopathologic features is key in differentiating KS from other conditions in the differential diagnosis.  

The patient's history of late latent syphilis coinfected with HIV and persistently elevated rapid plasma reagin that was recalcitrant to therapy placed an atypical nodular presentation within reason for the differential diagnosis. Deviations from the typical papulosquamous presentation with acral involvement in an immunocompromised patient mandates a consideration for syphilis with an atypical presentation. Atypical presentations include nodular, annular, pustular, lues maligna, frambesiform, corymbose, and photosensitive distributions.^7,8 Notably, coinfection with HIV modifies the clinical presentation, serology, and efficacy of treatment.^7-10 Atypical presentations are more common in coinfected HIV-positive patients, mandating a high degree of suspicion. Nodular secondary syphilis and the noduloulcerative form (lues maligna) often spare the palmar and plantar surfaces, and patients often have constitutional symptoms accompanying the cutaneous eruptions. In questionable cases, a biopsy lends clarification. Light microscopy on hematoxylin and eosin (H&E) staining may display acanthosis, superficial and deep perivascular swelling, plasma, histiocyte infiltrates, dermoepidermal junction changes, mixed patterns, epidermal hyperplasia, and dermal vascular thickening.^7-9,11 Spirochetes may be observed on Warthin-Starry stain; however, artifact obscuration from melanin granules and reticular fibers or paucity of organisms can make identification difficult. Immunohistochemical staining may prove useful when H&E stains are atypical or have a paucity of organisms or plasma cells or when silver stains have artifactual obscuration.⁹ Our patient's solitary palmar lesion without constitutional symptoms made an atypical nodular secondary syphilis presentation less likely. Ultimately, the histopathologic findings were consistent with KS.  

Bacillary angiomatosis (BA) is caused by Bartonella species and results in vascular proliferation with cutaneous manifestation. It frequently is observed in patients with HIV or other immunosuppressive conditions as well as patients with exposure to mammals or their vectors. Protean cutaneous manifestations and distributions of BA exist. The number of lesions can be singular to thousands. Solitary superficial pyogenic granuloma-like lesions can be clinically indistinguishable from both KS and pyogenic granuloma (PG). Superficial lesions often begin as red, violaceous, or flesh-colored papules that hemorrhage easily with trauma. The morphology of the papule can progress to be exophytic with dome-shaped or ulcerative surface features and is rubbery on palpation.¹² Biopsy is required to differentiate BA from KS. Bacillary angiomatosis on light microscopy with H&E shows protuberant, lobulated, round vessels with plump endothelial cells with or without necrosis. A neutrophil infiltrate in close proximity to bacilli may be noted. Warthin-Starry stain demonstrates numerous bacilli juxtaposed to these endothelial cells. The lack of immunohistochemical staining for HHV-8 also differentiates BA from KS.^12,13  

Pyogenic granuloma is resultant from proliferation of endothelial cells with a lobular architecture. Pyogenic granulomas are benign, rapidly progressive, acquired lesions presenting in the skin and mucous membranes. Pyogenic granuloma often presents as a single painless papule or nodule with a glistening red-violaceous color that occasionally appears with a perilesional collarette. The lesions are friable and easily hemorrhage. Pyogenic granuloma has been associated with local skin trauma and estrogen hormones. Histopathologic examination of PG assists with differentiation from other nodular lesions. Light microscopy with standard H&E staining demonstrates a network of capillaries arranged into a lobule surrounded by a fibrous matrix. Endothelial cells appear round and protrude into the vascular lamina. Mitotic activity is increased. Lack of findings on Warthin-Starry stain assists with differentiating PG from BA, while the microscopy architecture and immunohistochemical staining differentiates PG from KS.^6,13,14 

Squamous cell carcinoma (SCC) is the primary malignant cancer of the hand. The dorsal aspect of the hand is the most common location; SCC less commonly is located on the palmar surface, fingers, nail bed, or intertriginous areas.^15-17 Chakrabarti et al¹⁶ found that these lesions were invasive SCC when located on the palmar surface. Morphologically, SCC takes an exophytic papular, nodular, or scaly appearance with a red to flesh-colored appearance and poor demarcation of the borders. Progression to large ulcerated or secondarily infected lesions also can occur. The inflammatory reaction may cause tenderness to palpation and hemorrhage with trauma. Histopathologic examination of invasive SCC reveals atypical keratinocytes violating the basement membrane and abundant cytoplasm. Our patient's clinical presentation placed invasive SCC low on the differential diagnosis, and the histopathologic and immunohistochemical results eliminated SCC as the diagnosis. 

The Diagnosis: Nodular Kaposi Sarcoma 

Epidemic Kaposi sarcoma (KS) primarily affects patients with human immunodeficiency virus (HIV) infection. Kaposi sarcoma can appear as brown, red, or blue-black macules, plaques, patches, nodules, or tumors, and it often is observed as multifocal cutaneous lesions located on the head, neck, and upper aspects of the trunk in a fulminant manner. Kaposi sarcoma portends a poor prognosis and is an AIDS-defining malignancy.^1-3 Importantly, antiretroviral therapy does not preclude its consideration in those without AIDS-defining CD4 cell counts and undetectable HIV viremia presenting with cutaneous manifestations.^2,3 A retrospective review by Daly et al⁴ reported KS lesions in patients with CD4 lymphocyte counts greater than 300 cells/µL, most of whom were antiretroviral therapy-naïve patients. Also, those with higher CD4 counts tended to have a solitary KS lesion at presentation, while those with CD4 counts less than 300 cells/µL tended to present with multiple foci.⁴ Epidemic KS lesions are clinically indistinguishable from other common cutaneous conditions in the differential diagnosis of KS, necessitating biopsy for histopathologic examination. Light microscopy findings help to delineate the diagnosis of KS. Immunohistochemical staining to the latent nuclear antigen 1 of human herpesvirus 8 (HHV-8) confirms the KS diagnosis.^5,6 Our patient's presentation as a solitary acral lesion was atypical for KS.  

Light microscopy of our patient's biopsy demonstrated a large tumor on the acral surface of the right hand. Dermal collections of basophilic spindled cells clustered with small slitlike vascular spaces with abundant erythrocyte extravasation and numerous large ectatic vessels at the periphery were seen (Figure, A). At higher magnification, interlaced bundles of spindle cells with slitlike vessels with scattered lymphocytes and plasma cells were seen (Figure, B). An immunohistochemical stain for HHV-8 was positive and largely confined to spindle cells (Figure, C). These findings confirmed KS and met AIDS-defining criteria. Awareness of these histopathologic features is key in differentiating KS from other conditions in the differential diagnosis.  

The patient's history of late latent syphilis coinfected with HIV and persistently elevated rapid plasma reagin that was recalcitrant to therapy placed an atypical nodular presentation within reason for the differential diagnosis. Deviations from the typical papulosquamous presentation with acral involvement in an immunocompromised patient mandates a consideration for syphilis with an atypical presentation. Atypical presentations include nodular, annular, pustular, lues maligna, frambesiform, corymbose, and photosensitive distributions.^7,8 Notably, coinfection with HIV modifies the clinical presentation, serology, and efficacy of treatment.^7-10 Atypical presentations are more common in coinfected HIV-positive patients, mandating a high degree of suspicion. Nodular secondary syphilis and the noduloulcerative form (lues maligna) often spare the palmar and plantar surfaces, and patients often have constitutional symptoms accompanying the cutaneous eruptions. In questionable cases, a biopsy lends clarification. Light microscopy on hematoxylin and eosin (H&E) staining may display acanthosis, superficial and deep perivascular swelling, plasma, histiocyte infiltrates, dermoepidermal junction changes, mixed patterns, epidermal hyperplasia, and dermal vascular thickening.^7-9,11 Spirochetes may be observed on Warthin-Starry stain; however, artifact obscuration from melanin granules and reticular fibers or paucity of organisms can make identification difficult. Immunohistochemical staining may prove useful when H&E stains are atypical or have a paucity of organisms or plasma cells or when silver stains have artifactual obscuration.⁹ Our patient's solitary palmar lesion without constitutional symptoms made an atypical nodular secondary syphilis presentation less likely. Ultimately, the histopathologic findings were consistent with KS.  

Bacillary angiomatosis (BA) is caused by Bartonella species and results in vascular proliferation with cutaneous manifestation. It frequently is observed in patients with HIV or other immunosuppressive conditions as well as patients with exposure to mammals or their vectors. Protean cutaneous manifestations and distributions of BA exist. The number of lesions can be singular to thousands. Solitary superficial pyogenic granuloma-like lesions can be clinically indistinguishable from both KS and pyogenic granuloma (PG). Superficial lesions often begin as red, violaceous, or flesh-colored papules that hemorrhage easily with trauma. The morphology of the papule can progress to be exophytic with dome-shaped or ulcerative surface features and is rubbery on palpation.¹² Biopsy is required to differentiate BA from KS. Bacillary angiomatosis on light microscopy with H&E shows protuberant, lobulated, round vessels with plump endothelial cells with or without necrosis. A neutrophil infiltrate in close proximity to bacilli may be noted. Warthin-Starry stain demonstrates numerous bacilli juxtaposed to these endothelial cells. The lack of immunohistochemical staining for HHV-8 also differentiates BA from KS.^12,13  

Pyogenic granuloma is resultant from proliferation of endothelial cells with a lobular architecture. Pyogenic granulomas are benign, rapidly progressive, acquired lesions presenting in the skin and mucous membranes. Pyogenic granuloma often presents as a single painless papule or nodule with a glistening red-violaceous color that occasionally appears with a perilesional collarette. The lesions are friable and easily hemorrhage. Pyogenic granuloma has been associated with local skin trauma and estrogen hormones. Histopathologic examination of PG assists with differentiation from other nodular lesions. Light microscopy with standard H&E staining demonstrates a network of capillaries arranged into a lobule surrounded by a fibrous matrix. Endothelial cells appear round and protrude into the vascular lamina. Mitotic activity is increased. Lack of findings on Warthin-Starry stain assists with differentiating PG from BA, while the microscopy architecture and immunohistochemical staining differentiates PG from KS.^6,13,14 

Squamous cell carcinoma (SCC) is the primary malignant cancer of the hand. The dorsal aspect of the hand is the most common location; SCC less commonly is located on the palmar surface, fingers, nail bed, or intertriginous areas.^15-17 Chakrabarti et al¹⁶ found that these lesions were invasive SCC when located on the palmar surface. Morphologically, SCC takes an exophytic papular, nodular, or scaly appearance with a red to flesh-colored appearance and poor demarcation of the borders. Progression to large ulcerated or secondarily infected lesions also can occur. The inflammatory reaction may cause tenderness to palpation and hemorrhage with trauma. Histopathologic examination of invasive SCC reveals atypical keratinocytes violating the basement membrane and abundant cytoplasm. Our patient's clinical presentation placed invasive SCC low on the differential diagnosis, and the histopathologic and immunohistochemical results eliminated SCC as the diagnosis. 

The Diagnosis: Juvenile Xanthogranuloma

Juvenile xanthogranuloma (JXG) was first described in 1905 by Adamson1 as solitary or multiple plaquiform or nodular lesions that are yellow to yellowish brown. In 1954, Helwig and Hackney² coined the term juvenile xanthogranuloma to define this histiocytic cutaneous granulomatous tumor.

Juvenile xanthogranuloma is a rare dermatologic disorder that may be present at birth and primarily affects infants and young children. The benign lesions generally occur in the first 4 years of life, with a median age of onset of 2 years.³ Lesions range in size from millimeters to several centimeters in diameter.⁴ The skin of the head and neck is the most commonly involved site in JXG. The most frequent noncutaneous site of JXG involvement is the eye, particularly the iris, accounting for 0.4% of cases.^5,6 Extracutaneous sites such as the heart, liver, lungs, spleen, oral cavity, and brain also may be involved.⁴

Most children with JXG are asymptomatic. Skin lesions present as well-demarcated, rubbery, tan-orange papules or nodules. They usually are solitary, and multiple nodules can increase the risk for extracutaneous involvement.⁴ A case series of patients with neurofibromatosis type 1 showed 14 of 77 (18%) patients examined in the first year of life presented with JXG or other non–Langerhans cell histiocytosis.⁷ The adult form of cutaneous xanthogranuloma often presents with severe bronchial asthma.⁸

Histopathologic examination of a biopsy of the lesion typically demonstrates well-circumscribed nodules with dense infiltrates of polyhedral histiocytes with vaculoles.^3-7 In 85% of cases, Touton giant cells are present.^4,9 A prominent vascular network often is present, which was observed in our patient’s biopsy (Figure 1). Immunohistochemistry typically is positive for CD14, CD68, CD163, fascin, and factor XIIIa.^4,10 Classically, the cells are negative for S-100 and CD1a, which differentiates these lesions from Langerhans cell histiocytosis.^4-7,10 Our patient demonstrated scattered S-100–positive cells representing background dendritic cells and macrophages (Figure 2). The remainder of the clinical, morphologic, and immunophenotypic findings were consistent with non–Langerhans cell histiocytosis, specifically JXG.

Biopsy should be performed in all cases, and basic laboratory test results such as a complete blood cell count and basic metabolic panel also are appropriate. Routine referral of all patients with cutaneous JXG for ophthalmologic evaluation is not recommended.¹¹ Most patients with ocular involvement present with acute ocular concerns; asymptomatic eye involvement is rare. It is reasonable to consider referral to ophthalmology for patients younger than 2 years who present with multiple lesions, as they may have a higher risk for ocular involvement.¹¹

Juvenile xanthogranuloma usually is a benign disorder with management involving observation, as the lesions typically involute spontaneously.^3-7,9,10,12 Systemic or intralesional corticosteroids may be used for treatment in lesions that do not resolve. Ocular JXG refractory to steroid treatment has been managed in several cases with intravitreal bevacizumab.¹³ Additionally, surgical excision can be considered if malignancy is suspected, the lesion does not resolve with observation or steroid treatment, or the lesion is located near vital structures.^4-7,9-13

Spitz nevus presents as a single dome-shaped papule, but histology shows a symmetrical proliferation of spindle and epithelioid cells. Trachoma can present in and around the eye as a follicular hypertrophy but most commonly is seen in the conjunctiva. Dermoid cysts present as solitary subcutaneous cystic lesions; histology demonstrates a lining of keratinizing squamous epithelium with the presence of pilosebaceous structures. Dermatofibroma appears as a tan to reddish-brown papule in an area of prior minor trauma; pathology demonstrates an acanthotic epidermis with an underlying zone of normal papillary dermis and unencapsulated lesions with spindle cells overlapping in fascicles and whorls at the periphery.

The Diagnosis: Juvenile Xanthogranuloma

Juvenile xanthogranuloma (JXG) was first described in 1905 by Adamson1 as solitary or multiple plaquiform or nodular lesions that are yellow to yellowish brown. In 1954, Helwig and Hackney² coined the term juvenile xanthogranuloma to define this histiocytic cutaneous granulomatous tumor.

Juvenile xanthogranuloma is a rare dermatologic disorder that may be present at birth and primarily affects infants and young children. The benign lesions generally occur in the first 4 years of life, with a median age of onset of 2 years.³ Lesions range in size from millimeters to several centimeters in diameter.⁴ The skin of the head and neck is the most commonly involved site in JXG. The most frequent noncutaneous site of JXG involvement is the eye, particularly the iris, accounting for 0.4% of cases.^5,6 Extracutaneous sites such as the heart, liver, lungs, spleen, oral cavity, and brain also may be involved.⁴

Most children with JXG are asymptomatic. Skin lesions present as well-demarcated, rubbery, tan-orange papules or nodules. They usually are solitary, and multiple nodules can increase the risk for extracutaneous involvement.⁴ A case series of patients with neurofibromatosis type 1 showed 14 of 77 (18%) patients examined in the first year of life presented with JXG or other non–Langerhans cell histiocytosis.⁷ The adult form of cutaneous xanthogranuloma often presents with severe bronchial asthma.⁸

Histopathologic examination of a biopsy of the lesion typically demonstrates well-circumscribed nodules with dense infiltrates of polyhedral histiocytes with vaculoles.^3-7 In 85% of cases, Touton giant cells are present.^4,9 A prominent vascular network often is present, which was observed in our patient’s biopsy (Figure 1). Immunohistochemistry typically is positive for CD14, CD68, CD163, fascin, and factor XIIIa.^4,10 Classically, the cells are negative for S-100 and CD1a, which differentiates these lesions from Langerhans cell histiocytosis.^4-7,10 Our patient demonstrated scattered S-100–positive cells representing background dendritic cells and macrophages (Figure 2). The remainder of the clinical, morphologic, and immunophenotypic findings were consistent with non–Langerhans cell histiocytosis, specifically JXG.

Biopsy should be performed in all cases, and basic laboratory test results such as a complete blood cell count and basic metabolic panel also are appropriate. Routine referral of all patients with cutaneous JXG for ophthalmologic evaluation is not recommended.¹¹ Most patients with ocular involvement present with acute ocular concerns; asymptomatic eye involvement is rare. It is reasonable to consider referral to ophthalmology for patients younger than 2 years who present with multiple lesions, as they may have a higher risk for ocular involvement.¹¹

Juvenile xanthogranuloma usually is a benign disorder with management involving observation, as the lesions typically involute spontaneously.^3-7,9,10,12 Systemic or intralesional corticosteroids may be used for treatment in lesions that do not resolve. Ocular JXG refractory to steroid treatment has been managed in several cases with intravitreal bevacizumab.¹³ Additionally, surgical excision can be considered if malignancy is suspected, the lesion does not resolve with observation or steroid treatment, or the lesion is located near vital structures.^4-7,9-13

Spitz nevus presents as a single dome-shaped papule, but histology shows a symmetrical proliferation of spindle and epithelioid cells. Trachoma can present in and around the eye as a follicular hypertrophy but most commonly is seen in the conjunctiva. Dermoid cysts present as solitary subcutaneous cystic lesions; histology demonstrates a lining of keratinizing squamous epithelium with the presence of pilosebaceous structures. Dermatofibroma appears as a tan to reddish-brown papule in an area of prior minor trauma; pathology demonstrates an acanthotic epidermis with an underlying zone of normal papillary dermis and unencapsulated lesions with spindle cells overlapping in fascicles and whorls at the periphery.

The Diagnosis: Juvenile Xanthogranuloma

Juvenile xanthogranuloma (JXG) was first described in 1905 by Adamson1 as solitary or multiple plaquiform or nodular lesions that are yellow to yellowish brown. In 1954, Helwig and Hackney² coined the term juvenile xanthogranuloma to define this histiocytic cutaneous granulomatous tumor.

Juvenile xanthogranuloma is a rare dermatologic disorder that may be present at birth and primarily affects infants and young children. The benign lesions generally occur in the first 4 years of life, with a median age of onset of 2 years.³ Lesions range in size from millimeters to several centimeters in diameter.⁴ The skin of the head and neck is the most commonly involved site in JXG. The most frequent noncutaneous site of JXG involvement is the eye, particularly the iris, accounting for 0.4% of cases.^5,6 Extracutaneous sites such as the heart, liver, lungs, spleen, oral cavity, and brain also may be involved.⁴

Most children with JXG are asymptomatic. Skin lesions present as well-demarcated, rubbery, tan-orange papules or nodules. They usually are solitary, and multiple nodules can increase the risk for extracutaneous involvement.⁴ A case series of patients with neurofibromatosis type 1 showed 14 of 77 (18%) patients examined in the first year of life presented with JXG or other non–Langerhans cell histiocytosis.⁷ The adult form of cutaneous xanthogranuloma often presents with severe bronchial asthma.⁸

Histopathologic examination of a biopsy of the lesion typically demonstrates well-circumscribed nodules with dense infiltrates of polyhedral histiocytes with vaculoles.^3-7 In 85% of cases, Touton giant cells are present.^4,9 A prominent vascular network often is present, which was observed in our patient’s biopsy (Figure 1). Immunohistochemistry typically is positive for CD14, CD68, CD163, fascin, and factor XIIIa.^4,10 Classically, the cells are negative for S-100 and CD1a, which differentiates these lesions from Langerhans cell histiocytosis.^4-7,10 Our patient demonstrated scattered S-100–positive cells representing background dendritic cells and macrophages (Figure 2). The remainder of the clinical, morphologic, and immunophenotypic findings were consistent with non–Langerhans cell histiocytosis, specifically JXG.

Biopsy should be performed in all cases, and basic laboratory test results such as a complete blood cell count and basic metabolic panel also are appropriate. Routine referral of all patients with cutaneous JXG for ophthalmologic evaluation is not recommended.¹¹ Most patients with ocular involvement present with acute ocular concerns; asymptomatic eye involvement is rare. It is reasonable to consider referral to ophthalmology for patients younger than 2 years who present with multiple lesions, as they may have a higher risk for ocular involvement.¹¹

Juvenile xanthogranuloma usually is a benign disorder with management involving observation, as the lesions typically involute spontaneously.^3-7,9,10,12 Systemic or intralesional corticosteroids may be used for treatment in lesions that do not resolve. Ocular JXG refractory to steroid treatment has been managed in several cases with intravitreal bevacizumab.¹³ Additionally, surgical excision can be considered if malignancy is suspected, the lesion does not resolve with observation or steroid treatment, or the lesion is located near vital structures.^4-7,9-13

Spitz nevus presents as a single dome-shaped papule, but histology shows a symmetrical proliferation of spindle and epithelioid cells. Trachoma can present in and around the eye as a follicular hypertrophy but most commonly is seen in the conjunctiva. Dermoid cysts present as solitary subcutaneous cystic lesions; histology demonstrates a lining of keratinizing squamous epithelium with the presence of pilosebaceous structures. Dermatofibroma appears as a tan to reddish-brown papule in an area of prior minor trauma; pathology demonstrates an acanthotic epidermis with an underlying zone of normal papillary dermis and unencapsulated lesions with spindle cells overlapping in fascicles and whorls at the periphery.

The Diagnosis: Milia En Plaque 

Biopsy results revealed a normal epidermis; the dermis showed multiple small cystic structures lined by a stratified squamous epithelium containing eosinophilic keratin surrounded by a mononuclear cell infiltrate and some melanophages (Figure).  

Milia en plaque was first described in 1903 by Balzer and Fouquet.¹ In 1978, Hubler et al² presented 2 cases with an asymptomatic, erythematous, and edematous plaque and white milialike lesions. On histopathology, they showed multiple cystic structures characterized by central laminated keratin and an intense polymorphic inflammatory reaction surrounding the cyst and epidermal appendages. Both patients were treated with topical tretinoin with complete response at 3 months. The authors suggested the term milia en plaque to describe this clinical entity.² 

Milia en plaque is described as an infrequent condition that more often presents on the head, neck, and trunk, as well as the periocular, periauricular, and perinasal areas. It has been reported to occur at any age³ but appears more frequently in middle-aged adults and females. A congenital case also has been reported.⁴ It has been associated with pseudoxanthoma elasticum, lichen planus, trauma, kidney transplant, and cyclosporine use, but it also can present in healthy individuals,³ as in our patient. No clear cause has been identified. 

Pathology is characteristic, with multiple cysts filled with keratin and surrounded by 2 or 3 layers of epithelial cells, associated with a mononuclear, nonlichenoid, mononuclear infiltrate.⁵ Structures similar to follicular infundibular tumors have been described, suggesting a common origin of follicular lesions as milia en plaque.⁶  

Treatment includes surgical excision, cryosurgery, dermabrasion, electrodesiccation, trichloroacetic acid, photodynamic therapy, CO₂ and erbium lasers, topical retinoids, minocycline, and etretinate.⁷ We performed a complete surgical excision in our patient.  

In acneform reactions, erythematous papules and pustules can be found on the cheeks and forehead. Nevus comedonicus appears during childhood and presents with multiple open comedones. Postinflammatory milia is present in chronic inflammatory pathologies such as porphyria cutanea tarda. Histopathologic findings in adnexal tumors show a benign proliferation of any cellular type of a cutaneous annex. 

Milia en plaque is an unusual but benign condition that is distinguished clinically by its characteristic presentation. 

The Diagnosis: Milia En Plaque 

Biopsy results revealed a normal epidermis; the dermis showed multiple small cystic structures lined by a stratified squamous epithelium containing eosinophilic keratin surrounded by a mononuclear cell infiltrate and some melanophages (Figure).  

Milia en plaque was first described in 1903 by Balzer and Fouquet.¹ In 1978, Hubler et al² presented 2 cases with an asymptomatic, erythematous, and edematous plaque and white milialike lesions. On histopathology, they showed multiple cystic structures characterized by central laminated keratin and an intense polymorphic inflammatory reaction surrounding the cyst and epidermal appendages. Both patients were treated with topical tretinoin with complete response at 3 months. The authors suggested the term milia en plaque to describe this clinical entity.² 

Milia en plaque is described as an infrequent condition that more often presents on the head, neck, and trunk, as well as the periocular, periauricular, and perinasal areas. It has been reported to occur at any age³ but appears more frequently in middle-aged adults and females. A congenital case also has been reported.⁴ It has been associated with pseudoxanthoma elasticum, lichen planus, trauma, kidney transplant, and cyclosporine use, but it also can present in healthy individuals,³ as in our patient. No clear cause has been identified. 

Pathology is characteristic, with multiple cysts filled with keratin and surrounded by 2 or 3 layers of epithelial cells, associated with a mononuclear, nonlichenoid, mononuclear infiltrate.⁵ Structures similar to follicular infundibular tumors have been described, suggesting a common origin of follicular lesions as milia en plaque.⁶  

Treatment includes surgical excision, cryosurgery, dermabrasion, electrodesiccation, trichloroacetic acid, photodynamic therapy, CO₂ and erbium lasers, topical retinoids, minocycline, and etretinate.⁷ We performed a complete surgical excision in our patient.  

In acneform reactions, erythematous papules and pustules can be found on the cheeks and forehead. Nevus comedonicus appears during childhood and presents with multiple open comedones. Postinflammatory milia is present in chronic inflammatory pathologies such as porphyria cutanea tarda. Histopathologic findings in adnexal tumors show a benign proliferation of any cellular type of a cutaneous annex. 

Milia en plaque is an unusual but benign condition that is distinguished clinically by its characteristic presentation. 

The Diagnosis: Milia En Plaque 

Biopsy results revealed a normal epidermis; the dermis showed multiple small cystic structures lined by a stratified squamous epithelium containing eosinophilic keratin surrounded by a mononuclear cell infiltrate and some melanophages (Figure).  

Milia en plaque was first described in 1903 by Balzer and Fouquet.¹ In 1978, Hubler et al² presented 2 cases with an asymptomatic, erythematous, and edematous plaque and white milialike lesions. On histopathology, they showed multiple cystic structures characterized by central laminated keratin and an intense polymorphic inflammatory reaction surrounding the cyst and epidermal appendages. Both patients were treated with topical tretinoin with complete response at 3 months. The authors suggested the term milia en plaque to describe this clinical entity.² 

Milia en plaque is described as an infrequent condition that more often presents on the head, neck, and trunk, as well as the periocular, periauricular, and perinasal areas. It has been reported to occur at any age³ but appears more frequently in middle-aged adults and females. A congenital case also has been reported.⁴ It has been associated with pseudoxanthoma elasticum, lichen planus, trauma, kidney transplant, and cyclosporine use, but it also can present in healthy individuals,³ as in our patient. No clear cause has been identified. 

Pathology is characteristic, with multiple cysts filled with keratin and surrounded by 2 or 3 layers of epithelial cells, associated with a mononuclear, nonlichenoid, mononuclear infiltrate.⁵ Structures similar to follicular infundibular tumors have been described, suggesting a common origin of follicular lesions as milia en plaque.⁶  

Treatment includes surgical excision, cryosurgery, dermabrasion, electrodesiccation, trichloroacetic acid, photodynamic therapy, CO₂ and erbium lasers, topical retinoids, minocycline, and etretinate.⁷ We performed a complete surgical excision in our patient.  

In acneform reactions, erythematous papules and pustules can be found on the cheeks and forehead. Nevus comedonicus appears during childhood and presents with multiple open comedones. Postinflammatory milia is present in chronic inflammatory pathologies such as porphyria cutanea tarda. Histopathologic findings in adnexal tumors show a benign proliferation of any cellular type of a cutaneous annex. 

Milia en plaque is an unusual but benign condition that is distinguished clinically by its characteristic presentation. 

The Diagnosis: Factitial Purpura 

Factitial dermatologic disorders are characterized by skin findings triggered by deliberate manipulation of the skin with objects to create lesions and feign signs of a dermatologic condition to seek emotional and psychological benefit.¹ The etiology of the lesions is unclear, and the patient's history of the injury is hollow.² Most often, there is sudden onset of the lesions without any warning or symptoms. When giving the history, the patient may appear unemotional, does not report pain, and denies self-infliction.¹  

In factitial purpura, the purple patches are clearly demarcated from uninvolved skin and have an unusual angular or geometric shape. The pattern typically takes the shape of the object used to create the purpura and lacks the features of recognizable dermatoses.² In our patient and those with similar linear purpuric streaks, we use the term penny purpura to indicate that the lesions resulted from rubbing with a penny or other blunt object, similar to coining. The lesions occur in areas that are easily accessible and visible such as the arms, chest, or chin. It is suggested that the child unconsciously wants the lesions to be seen. Histologic findings in factitial purpura include disruption of collagen fiber bundles and extravasated red blood cells in the dermis.³ Unfortunately, evolving lesions may give nonspecific histologic findings; when the clinical lesions are typical, skin biopsy usually is unnecessary and may be misleading. Laboratory test results such as complete blood cell count, prothrombin time, and partial thromboplastin time usually are within reference range, as in our patient. 

When evaluating these patients, confrontation is not recommended. More than two-thirds of affected patients have a history of trauma such as sexual/physical abuse or neglect, and the lesions typically arise during times of stress.^1,3 Thus, treatment includes nonaccusatory measures and referral for psychologic evaluation. The purpura will rapidly heal when covered with an occlusive dressing.²  

The differential diagnosis for penny purpura includes lesions that evolve from cupping and coining. Cupping is a type of complementary and alternative medicine that acts by correcting imbalances in the internal biofield and restoring the flow of qi, which determines the state of one's health and life span.⁴ Cupping is performed by placing a glass cup over a painful body part. A partial vacuum is created by flaming, mechanical withdrawal, or thermal cooling of the entrapped air under the cup. When the flame exhausts the supply of oxygen, the skin is sucked into the mouth of the glass, and the skin is bruised painlessly.⁴  

The differential also includes child maltreatment syndrome and other disorders that would potentiate bruising. Intravascular etiologies include idiopathic thrombocytopenic purpura, leukemia, coagulation disorders, and other causes of thrombocytopenia or platelet dysfunction.³ Extravascular etiologies include hereditary collagen vascular disease (eg, Ehlers-Danlos syndrome), malnutrition, and other disorders associated with a decrease in collagen and other tissues that support cutaneous vessels. Vascular etiologies include infectious (eg, Rocky Mountain spotted fever, meningococcemia) and noninfectious vasculitis (eg, Henoch-Schönlein purpura), leaky capillary syndrome, drug reactions, and other disorders associated with a loss of vascular integrity.³  

It is important to be able to differentiate self-inflicted lesions in a person who repeatedly acts as if he/she has a physical disorder from those that are created during the practices of cupping or any other cultural healing practice. Vascular disorders, malnutrition, and child abuse also should be excluded.³  

For our patient with factitial purpura, we gently encouraged the family to work with the child's pediatrician and a pediatric psychologist to deal with stress related to the recurrent rash and asked them to think of the rash as a result of an external cause; however, we were careful not to blame anyone for the rash.  

The Diagnosis: Factitial Purpura 

Factitial dermatologic disorders are characterized by skin findings triggered by deliberate manipulation of the skin with objects to create lesions and feign signs of a dermatologic condition to seek emotional and psychological benefit.¹ The etiology of the lesions is unclear, and the patient's history of the injury is hollow.² Most often, there is sudden onset of the lesions without any warning or symptoms. When giving the history, the patient may appear unemotional, does not report pain, and denies self-infliction.¹  

In factitial purpura, the purple patches are clearly demarcated from uninvolved skin and have an unusual angular or geometric shape. The pattern typically takes the shape of the object used to create the purpura and lacks the features of recognizable dermatoses.² In our patient and those with similar linear purpuric streaks, we use the term penny purpura to indicate that the lesions resulted from rubbing with a penny or other blunt object, similar to coining. The lesions occur in areas that are easily accessible and visible such as the arms, chest, or chin. It is suggested that the child unconsciously wants the lesions to be seen. Histologic findings in factitial purpura include disruption of collagen fiber bundles and extravasated red blood cells in the dermis.³ Unfortunately, evolving lesions may give nonspecific histologic findings; when the clinical lesions are typical, skin biopsy usually is unnecessary and may be misleading. Laboratory test results such as complete blood cell count, prothrombin time, and partial thromboplastin time usually are within reference range, as in our patient. 

When evaluating these patients, confrontation is not recommended. More than two-thirds of affected patients have a history of trauma such as sexual/physical abuse or neglect, and the lesions typically arise during times of stress.^1,3 Thus, treatment includes nonaccusatory measures and referral for psychologic evaluation. The purpura will rapidly heal when covered with an occlusive dressing.²  

The differential diagnosis for penny purpura includes lesions that evolve from cupping and coining. Cupping is a type of complementary and alternative medicine that acts by correcting imbalances in the internal biofield and restoring the flow of qi, which determines the state of one's health and life span.⁴ Cupping is performed by placing a glass cup over a painful body part. A partial vacuum is created by flaming, mechanical withdrawal, or thermal cooling of the entrapped air under the cup. When the flame exhausts the supply of oxygen, the skin is sucked into the mouth of the glass, and the skin is bruised painlessly.⁴  

The differential also includes child maltreatment syndrome and other disorders that would potentiate bruising. Intravascular etiologies include idiopathic thrombocytopenic purpura, leukemia, coagulation disorders, and other causes of thrombocytopenia or platelet dysfunction.³ Extravascular etiologies include hereditary collagen vascular disease (eg, Ehlers-Danlos syndrome), malnutrition, and other disorders associated with a decrease in collagen and other tissues that support cutaneous vessels. Vascular etiologies include infectious (eg, Rocky Mountain spotted fever, meningococcemia) and noninfectious vasculitis (eg, Henoch-Schönlein purpura), leaky capillary syndrome, drug reactions, and other disorders associated with a loss of vascular integrity.³  

It is important to be able to differentiate self-inflicted lesions in a person who repeatedly acts as if he/she has a physical disorder from those that are created during the practices of cupping or any other cultural healing practice. Vascular disorders, malnutrition, and child abuse also should be excluded.³  

For our patient with factitial purpura, we gently encouraged the family to work with the child's pediatrician and a pediatric psychologist to deal with stress related to the recurrent rash and asked them to think of the rash as a result of an external cause; however, we were careful not to blame anyone for the rash.  

The Diagnosis: Factitial Purpura 

Factitial dermatologic disorders are characterized by skin findings triggered by deliberate manipulation of the skin with objects to create lesions and feign signs of a dermatologic condition to seek emotional and psychological benefit.¹ The etiology of the lesions is unclear, and the patient's history of the injury is hollow.² Most often, there is sudden onset of the lesions without any warning or symptoms. When giving the history, the patient may appear unemotional, does not report pain, and denies self-infliction.¹  

In factitial purpura, the purple patches are clearly demarcated from uninvolved skin and have an unusual angular or geometric shape. The pattern typically takes the shape of the object used to create the purpura and lacks the features of recognizable dermatoses.² In our patient and those with similar linear purpuric streaks, we use the term penny purpura to indicate that the lesions resulted from rubbing with a penny or other blunt object, similar to coining. The lesions occur in areas that are easily accessible and visible such as the arms, chest, or chin. It is suggested that the child unconsciously wants the lesions to be seen. Histologic findings in factitial purpura include disruption of collagen fiber bundles and extravasated red blood cells in the dermis.³ Unfortunately, evolving lesions may give nonspecific histologic findings; when the clinical lesions are typical, skin biopsy usually is unnecessary and may be misleading. Laboratory test results such as complete blood cell count, prothrombin time, and partial thromboplastin time usually are within reference range, as in our patient. 

When evaluating these patients, confrontation is not recommended. More than two-thirds of affected patients have a history of trauma such as sexual/physical abuse or neglect, and the lesions typically arise during times of stress.^1,3 Thus, treatment includes nonaccusatory measures and referral for psychologic evaluation. The purpura will rapidly heal when covered with an occlusive dressing.²  

The differential diagnosis for penny purpura includes lesions that evolve from cupping and coining. Cupping is a type of complementary and alternative medicine that acts by correcting imbalances in the internal biofield and restoring the flow of qi, which determines the state of one's health and life span.⁴ Cupping is performed by placing a glass cup over a painful body part. A partial vacuum is created by flaming, mechanical withdrawal, or thermal cooling of the entrapped air under the cup. When the flame exhausts the supply of oxygen, the skin is sucked into the mouth of the glass, and the skin is bruised painlessly.⁴  

The differential also includes child maltreatment syndrome and other disorders that would potentiate bruising. Intravascular etiologies include idiopathic thrombocytopenic purpura, leukemia, coagulation disorders, and other causes of thrombocytopenia or platelet dysfunction.³ Extravascular etiologies include hereditary collagen vascular disease (eg, Ehlers-Danlos syndrome), malnutrition, and other disorders associated with a decrease in collagen and other tissues that support cutaneous vessels. Vascular etiologies include infectious (eg, Rocky Mountain spotted fever, meningococcemia) and noninfectious vasculitis (eg, Henoch-Schönlein purpura), leaky capillary syndrome, drug reactions, and other disorders associated with a loss of vascular integrity.³  

It is important to be able to differentiate self-inflicted lesions in a person who repeatedly acts as if he/she has a physical disorder from those that are created during the practices of cupping or any other cultural healing practice. Vascular disorders, malnutrition, and child abuse also should be excluded.³  

For our patient with factitial purpura, we gently encouraged the family to work with the child's pediatrician and a pediatric psychologist to deal with stress related to the recurrent rash and asked them to think of the rash as a result of an external cause; however, we were careful not to blame anyone for the rash.  

The Diagnosis: Cutaneous B-Cell Lymphoma, Follicle Center Subtype 

A 4-mm punch biopsy through the center of the largest lesion on the right posterior shoulder demonstrated a superficial and deep dermal atypical lymphoid infiltrate composed predominantly of small mature lymphocytes with interspersed intermediate-sized cells with irregular to cleaved nuclei, dispersed chromatin, one or more distinct nucleoli, occasional mitoses, and small amounts of cytoplasm (Figure, A). Immunoperoxidase studies showed the infiltrate to be a mixture of CD3+ T cells and CD20+ B cells (Figure, B). The B cells coexpressed B-cell lymphoma (Bcl) 6 protein (Figure, C) but were negative for multiple myeloma 1/interferon regulatory factor 4 and CD10; Bcl2 protein was positive in T cells but inconclusive for staining in B cells. Very few plasma cells were seen with CD138 stain. Fluorescence in situ hybridization studies were negative for IgH and BCL2 gene rearrangement. Molecular diagnostic studies for IgH and κ light chain gene rearrangement were positive for a clonal population. A clonal T-cell receptor γ chain gene rearrangement was not identified. The overall morphologic, immunophenotypic, and molecular findings were consistent with cutaneous involvement by a B-cell lymphoproliferative disorder, favoring primary cutaneous follicle center lymphoma (PCFCL). 

The patient was referred to our cancer center for further workup consisting of a complete blood cell count with differential; comprehensive metabolic panel; lactate dehydrogenase; serum protein electrophoresis; peripheral blood flow cytometry; and computed tomography of the chest, abdomen, and pelvis. The analysis was unremarkable, supporting primary cutaneous disease. Additional studies suggested in the National Comprehensive Cancer Network (NCCN) Guidelines for primary cutaneous B-cell lymphomas include hepatitis B testing if the patient is being considered for immunotherapy and/or chemotherapy due to risk of reactivation, pregnancy testing in women of childbearing age, and human immunodeficiency virus testing.¹ These tests were not performed in our patient because he did not have any risk factors for hepatitis B or human immunodeficiency virus. 

Primary cutaneous B-cell lymphomas originate in the skin without evidence of extracutaneous disease at presentation. They account for approximately 25% of primary cutaneous lymphomas in the United States, with primary cutaneous T-cell lymphoma being most common.² The revised 2017 World Health Organization classification system defines 3 major subtypes of primary cutaneous B-cell lymphoma (Table).^3-9 Primary cutaneous follicle center lymphoma is the most common subtype, accounting for approximately 60% of cases. In Europe, an association with Borrelia burgdorferi has been reported.¹⁰ The extent of skin involvement determines the T portion of TNM staging for PCFCL. It is based on the size and location of affected body regions that are delineated, such as the head and neck, chest, abdomen/genitalia, upper back, lower back/buttocks, each upper arm, each lower arm/hand, each upper leg, and each lower leg/foot. T1 is for solitary skin involvement in which the lesion is 5 cm or less in diameter (T1a) or greater than 5 cm (T1b). T2 is for regional skin involvement limited to 1 or 2 contiguous body regions, whereas T2a has all lesions confined to an area 15 cm or less in diameter, T2b has lesions confined to an area greater than 15 cm up to 30 cm in diameter, and the area for T2c is greater than 30 cm in diameter. Finally, T3 is generalized skin involvement, whereas T3a has multiple lesions in 2 noncontiguous body regions, and T3b has multiple lesions on 3 or more regions.¹¹ At presentation, our patient was considered T2cN0M0, as his lesions were present on only 2 contiguous regions extending beyond 30 cm without any evidence of lymph node involvement or metastasis.  

Treatment of PCFCL is tailored to each case, as there is a paucity of randomized data in this rare entity. It is guided by the number and location of cutaneous lesions, associated skin symptoms, age of the patient, and performance status. Local disease can be treated with intralesional corticosteroids, excision, or close monitoring if the patient is asymptomatic. Low-dose radiation therapy may be used as primary treatment or for local recurrence.¹² Patients with more extensive skin lesions can relapse after clearing; those with refractory disease can be managed with single-agent rituximab.¹³ Our patient underwent low-dose radiation therapy with good response and has not experienced recurrence. 

Lymphocytoma cutis, also known as benign reactive lymphoid hyperplasia, can be idiopathic or can arise after arthropod assault, penetrative skin trauma, drugs, or infections. In granuloma annulare, small dermal papules may present in isolation or coalesce to form annular plaques. It is a benign inflammatory disorder of unknown cause, can have mild pruritus, and usually is self-limited. Pyogenic granuloma is a benign vascular proliferation of unknown etiology. Sarcoidosis is an immune-mediated systemic disorder with granuloma formation that has a predilection for the lungs and the skin. 

The Diagnosis: Cutaneous B-Cell Lymphoma, Follicle Center Subtype 

A 4-mm punch biopsy through the center of the largest lesion on the right posterior shoulder demonstrated a superficial and deep dermal atypical lymphoid infiltrate composed predominantly of small mature lymphocytes with interspersed intermediate-sized cells with irregular to cleaved nuclei, dispersed chromatin, one or more distinct nucleoli, occasional mitoses, and small amounts of cytoplasm (Figure, A). Immunoperoxidase studies showed the infiltrate to be a mixture of CD3+ T cells and CD20+ B cells (Figure, B). The B cells coexpressed B-cell lymphoma (Bcl) 6 protein (Figure, C) but were negative for multiple myeloma 1/interferon regulatory factor 4 and CD10; Bcl2 protein was positive in T cells but inconclusive for staining in B cells. Very few plasma cells were seen with CD138 stain. Fluorescence in situ hybridization studies were negative for IgH and BCL2 gene rearrangement. Molecular diagnostic studies for IgH and κ light chain gene rearrangement were positive for a clonal population. A clonal T-cell receptor γ chain gene rearrangement was not identified. The overall morphologic, immunophenotypic, and molecular findings were consistent with cutaneous involvement by a B-cell lymphoproliferative disorder, favoring primary cutaneous follicle center lymphoma (PCFCL). 

The patient was referred to our cancer center for further workup consisting of a complete blood cell count with differential; comprehensive metabolic panel; lactate dehydrogenase; serum protein electrophoresis; peripheral blood flow cytometry; and computed tomography of the chest, abdomen, and pelvis. The analysis was unremarkable, supporting primary cutaneous disease. Additional studies suggested in the National Comprehensive Cancer Network (NCCN) Guidelines for primary cutaneous B-cell lymphomas include hepatitis B testing if the patient is being considered for immunotherapy and/or chemotherapy due to risk of reactivation, pregnancy testing in women of childbearing age, and human immunodeficiency virus testing.¹ These tests were not performed in our patient because he did not have any risk factors for hepatitis B or human immunodeficiency virus. 

Primary cutaneous B-cell lymphomas originate in the skin without evidence of extracutaneous disease at presentation. They account for approximately 25% of primary cutaneous lymphomas in the United States, with primary cutaneous T-cell lymphoma being most common.² The revised 2017 World Health Organization classification system defines 3 major subtypes of primary cutaneous B-cell lymphoma (Table).^3-9 Primary cutaneous follicle center lymphoma is the most common subtype, accounting for approximately 60% of cases. In Europe, an association with Borrelia burgdorferi has been reported.¹⁰ The extent of skin involvement determines the T portion of TNM staging for PCFCL. It is based on the size and location of affected body regions that are delineated, such as the head and neck, chest, abdomen/genitalia, upper back, lower back/buttocks, each upper arm, each lower arm/hand, each upper leg, and each lower leg/foot. T1 is for solitary skin involvement in which the lesion is 5 cm or less in diameter (T1a) or greater than 5 cm (T1b). T2 is for regional skin involvement limited to 1 or 2 contiguous body regions, whereas T2a has all lesions confined to an area 15 cm or less in diameter, T2b has lesions confined to an area greater than 15 cm up to 30 cm in diameter, and the area for T2c is greater than 30 cm in diameter. Finally, T3 is generalized skin involvement, whereas T3a has multiple lesions in 2 noncontiguous body regions, and T3b has multiple lesions on 3 or more regions.¹¹ At presentation, our patient was considered T2cN0M0, as his lesions were present on only 2 contiguous regions extending beyond 30 cm without any evidence of lymph node involvement or metastasis.  

Treatment of PCFCL is tailored to each case, as there is a paucity of randomized data in this rare entity. It is guided by the number and location of cutaneous lesions, associated skin symptoms, age of the patient, and performance status. Local disease can be treated with intralesional corticosteroids, excision, or close monitoring if the patient is asymptomatic. Low-dose radiation therapy may be used as primary treatment or for local recurrence.¹² Patients with more extensive skin lesions can relapse after clearing; those with refractory disease can be managed with single-agent rituximab.¹³ Our patient underwent low-dose radiation therapy with good response and has not experienced recurrence. 

Lymphocytoma cutis, also known as benign reactive lymphoid hyperplasia, can be idiopathic or can arise after arthropod assault, penetrative skin trauma, drugs, or infections. In granuloma annulare, small dermal papules may present in isolation or coalesce to form annular plaques. It is a benign inflammatory disorder of unknown cause, can have mild pruritus, and usually is self-limited. Pyogenic granuloma is a benign vascular proliferation of unknown etiology. Sarcoidosis is an immune-mediated systemic disorder with granuloma formation that has a predilection for the lungs and the skin. 

The Diagnosis: Cutaneous B-Cell Lymphoma, Follicle Center Subtype 

A 4-mm punch biopsy through the center of the largest lesion on the right posterior shoulder demonstrated a superficial and deep dermal atypical lymphoid infiltrate composed predominantly of small mature lymphocytes with interspersed intermediate-sized cells with irregular to cleaved nuclei, dispersed chromatin, one or more distinct nucleoli, occasional mitoses, and small amounts of cytoplasm (Figure, A). Immunoperoxidase studies showed the infiltrate to be a mixture of CD3+ T cells and CD20+ B cells (Figure, B). The B cells coexpressed B-cell lymphoma (Bcl) 6 protein (Figure, C) but were negative for multiple myeloma 1/interferon regulatory factor 4 and CD10; Bcl2 protein was positive in T cells but inconclusive for staining in B cells. Very few plasma cells were seen with CD138 stain. Fluorescence in situ hybridization studies were negative for IgH and BCL2 gene rearrangement. Molecular diagnostic studies for IgH and κ light chain gene rearrangement were positive for a clonal population. A clonal T-cell receptor γ chain gene rearrangement was not identified. The overall morphologic, immunophenotypic, and molecular findings were consistent with cutaneous involvement by a B-cell lymphoproliferative disorder, favoring primary cutaneous follicle center lymphoma (PCFCL). 

The patient was referred to our cancer center for further workup consisting of a complete blood cell count with differential; comprehensive metabolic panel; lactate dehydrogenase; serum protein electrophoresis; peripheral blood flow cytometry; and computed tomography of the chest, abdomen, and pelvis. The analysis was unremarkable, supporting primary cutaneous disease. Additional studies suggested in the National Comprehensive Cancer Network (NCCN) Guidelines for primary cutaneous B-cell lymphomas include hepatitis B testing if the patient is being considered for immunotherapy and/or chemotherapy due to risk of reactivation, pregnancy testing in women of childbearing age, and human immunodeficiency virus testing.¹ These tests were not performed in our patient because he did not have any risk factors for hepatitis B or human immunodeficiency virus. 

Primary cutaneous B-cell lymphomas originate in the skin without evidence of extracutaneous disease at presentation. They account for approximately 25% of primary cutaneous lymphomas in the United States, with primary cutaneous T-cell lymphoma being most common.² The revised 2017 World Health Organization classification system defines 3 major subtypes of primary cutaneous B-cell lymphoma (Table).^3-9 Primary cutaneous follicle center lymphoma is the most common subtype, accounting for approximately 60% of cases. In Europe, an association with Borrelia burgdorferi has been reported.¹⁰ The extent of skin involvement determines the T portion of TNM staging for PCFCL. It is based on the size and location of affected body regions that are delineated, such as the head and neck, chest, abdomen/genitalia, upper back, lower back/buttocks, each upper arm, each lower arm/hand, each upper leg, and each lower leg/foot. T1 is for solitary skin involvement in which the lesion is 5 cm or less in diameter (T1a) or greater than 5 cm (T1b). T2 is for regional skin involvement limited to 1 or 2 contiguous body regions, whereas T2a has all lesions confined to an area 15 cm or less in diameter, T2b has lesions confined to an area greater than 15 cm up to 30 cm in diameter, and the area for T2c is greater than 30 cm in diameter. Finally, T3 is generalized skin involvement, whereas T3a has multiple lesions in 2 noncontiguous body regions, and T3b has multiple lesions on 3 or more regions.¹¹ At presentation, our patient was considered T2cN0M0, as his lesions were present on only 2 contiguous regions extending beyond 30 cm without any evidence of lymph node involvement or metastasis.  

Treatment of PCFCL is tailored to each case, as there is a paucity of randomized data in this rare entity. It is guided by the number and location of cutaneous lesions, associated skin symptoms, age of the patient, and performance status. Local disease can be treated with intralesional corticosteroids, excision, or close monitoring if the patient is asymptomatic. Low-dose radiation therapy may be used as primary treatment or for local recurrence.¹² Patients with more extensive skin lesions can relapse after clearing; those with refractory disease can be managed with single-agent rituximab.¹³ Our patient underwent low-dose radiation therapy with good response and has not experienced recurrence. 

Lymphocytoma cutis, also known as benign reactive lymphoid hyperplasia, can be idiopathic or can arise after arthropod assault, penetrative skin trauma, drugs, or infections. In granuloma annulare, small dermal papules may present in isolation or coalesce to form annular plaques. It is a benign inflammatory disorder of unknown cause, can have mild pruritus, and usually is self-limited. Pyogenic granuloma is a benign vascular proliferation of unknown etiology. Sarcoidosis is an immune-mediated systemic disorder with granuloma formation that has a predilection for the lungs and the skin. 

The Diagnosis: Atypical Fibroxanthoma  

Shave biopsy showed the superficial aspect of a highly cellular tumor composed of pleomorphic spindle cells exhibiting storiform growth and increased mitotic activity (Figure 1). The tumor stained positive for factor XIIIa, CD163, CD68, and smooth muscle actin (mild), and negative for high-molecular-weight cytokeratin (HMW-CK), p63, S-100, and melan-A. Subsequent excision with 0.5-cm margins was performed, and histopathology showed a well-circumscribed tumor contained within the dermis with a histologic scar at the outer margin (Figure 2). There was no lymphovascular or perineural invasion by tumor cells. Re-excision with 0.3-cm margins demonstrated no residual scar or tumor, and external radiation was deferred due to clear surgical margins.  

Atypical fibroxanthoma (AFX) belongs to a group of spindle cell neoplasms that can be diagnostically challenging, as they often lack specific morphologic features on examination or routine histology. These neoplasms--of which the differential includes malignant fibrous histiocytoma, spindle cell squamous cell carcinoma (SCC), desmoplastic melanoma, and leiomyosarcoma--may each appear as a rapidly enlarging solitary plaque or nodule on sun-damaged skin on the head and neck or less commonly on the trunk, arms, or legs. Histologically, the cells of AFX exhibit notable pleomorphism with frequent atypical mitotic figures and nonspecific surrounding dermal changes. Subcutaneous and lymphovascular or perineural invasion of tumor cells can point away from the diagnosis of AFX; however, these features are likely to be missed in small superficial shave biopsies.^1,2 Therefore, immunohistochemistry (IHC) and adequate tumor sampling are essential in the accurate diagnosis of AFX and other spindle cell neoplasms.  

Several IHC markers have been employed in differentiating AFX from other spindle cell neoplasms.^3-8 Positive stains for AFX include factor XIIIa (10%-25%), vimentin (>99%), CD10 (95%-100%), procollagen (87%), CD99 (35%-73%), CD163 (37%-79%), smooth muscle actin (50%), CD68 (>50%), and CD31 (43%). Other stains, such as HMW-CK, S-100, p63, desmin, CD34, and melan-A, typically are negative in AFX but are actively expressed in other pleomorphic spindle cell tumors. The Table summarizes the utility of these various markers in narrowing the differential diagnosis of a spindle cell lesion. Selection of an appropriate panel of IHC markers is critical for accurate diagnosis of AFX and exclusion of more aggressive, poorly differentiated spindle cell neoplasms. Key IHC markers include S-100 (negative in AFX; positive in desmoplastic melanoma), HMW-CK (negative in AFX; positive in spindle cell SCC), and p63 (negative in AFX; positive in spindle cell SCC). Benoit et al⁹ reported a case of a poorly differentiated spindle cell SCC misdiagnosed as AFX based on a limited IHC panel that was negative for pancytokeratin and S-100. Later, a more comprehensive IHC panel including HMW-CK and p63 confirmed spindle cell SCC, but by this time, a delay in therapy had allowed the tumor to metastasize, which ultimately proved fatal to the patient.⁹  

In addition to incomplete IHC evaluation, accurate diagnosis of spindle cell tumors also may be obscured by inadequate tumor sampling. The cells of AFX tumors often are well circumscribed and dermally based, and an excisional biopsy is the preferred biopsy procedure for AFX. A tumor invading into subcutaneous tissue or into lymphovascular or perineural structures suggests a more aggressive, poorly differentiated spindle cell neoplasm.^1,3 For example, the tumor cells of malignant fibrous histiocytoma, which belongs to the undifferentiated pleomorphic sarcoma group, may appear identical to those of AFX on histology, and the 2 tumors display similar IHC profiles.³ Malignant fibrous histiocytoma, however, extends into the subcutaneous space and portends a notably worse prognosis compared to AFX. Malignant fibrous histiocytoma tumors therefore require more aggressive treatment strategies such as external beam radiation therapy, whereas AFX can be safely treated with surgical removal alone. In our patient, complete visualization of tumor margins solidified the diagnosis of AFX and spared our patient from unnecessary radiation therapy. Overall, AFX has a good prognosis and metastasis is rare, particularly when good margin control is achieved.¹⁰ 

Our case highlights the importance of clinicopathologic correlation, including appropriate IHC analysis and adequate tumor sampling in the diagnostic workup of a pleomorphic spindle cell neoplasm. Although these tumors are well studied, their notable degree of clinical and histologic heterogeneity may pose a diagnostic challenge to even experienced dermatologists and require careful consideration of the potential pitfalls in diagnosis.  

The Diagnosis: Atypical Fibroxanthoma  

Shave biopsy showed the superficial aspect of a highly cellular tumor composed of pleomorphic spindle cells exhibiting storiform growth and increased mitotic activity (Figure 1). The tumor stained positive for factor XIIIa, CD163, CD68, and smooth muscle actin (mild), and negative for high-molecular-weight cytokeratin (HMW-CK), p63, S-100, and melan-A. Subsequent excision with 0.5-cm margins was performed, and histopathology showed a well-circumscribed tumor contained within the dermis with a histologic scar at the outer margin (Figure 2). There was no lymphovascular or perineural invasion by tumor cells. Re-excision with 0.3-cm margins demonstrated no residual scar or tumor, and external radiation was deferred due to clear surgical margins.  

Atypical fibroxanthoma (AFX) belongs to a group of spindle cell neoplasms that can be diagnostically challenging, as they often lack specific morphologic features on examination or routine histology. These neoplasms--of which the differential includes malignant fibrous histiocytoma, spindle cell squamous cell carcinoma (SCC), desmoplastic melanoma, and leiomyosarcoma--may each appear as a rapidly enlarging solitary plaque or nodule on sun-damaged skin on the head and neck or less commonly on the trunk, arms, or legs. Histologically, the cells of AFX exhibit notable pleomorphism with frequent atypical mitotic figures and nonspecific surrounding dermal changes. Subcutaneous and lymphovascular or perineural invasion of tumor cells can point away from the diagnosis of AFX; however, these features are likely to be missed in small superficial shave biopsies.^1,2 Therefore, immunohistochemistry (IHC) and adequate tumor sampling are essential in the accurate diagnosis of AFX and other spindle cell neoplasms.  

Several IHC markers have been employed in differentiating AFX from other spindle cell neoplasms.^3-8 Positive stains for AFX include factor XIIIa (10%-25%), vimentin (>99%), CD10 (95%-100%), procollagen (87%), CD99 (35%-73%), CD163 (37%-79%), smooth muscle actin (50%), CD68 (>50%), and CD31 (43%). Other stains, such as HMW-CK, S-100, p63, desmin, CD34, and melan-A, typically are negative in AFX but are actively expressed in other pleomorphic spindle cell tumors. The Table summarizes the utility of these various markers in narrowing the differential diagnosis of a spindle cell lesion. Selection of an appropriate panel of IHC markers is critical for accurate diagnosis of AFX and exclusion of more aggressive, poorly differentiated spindle cell neoplasms. Key IHC markers include S-100 (negative in AFX; positive in desmoplastic melanoma), HMW-CK (negative in AFX; positive in spindle cell SCC), and p63 (negative in AFX; positive in spindle cell SCC). Benoit et al⁹ reported a case of a poorly differentiated spindle cell SCC misdiagnosed as AFX based on a limited IHC panel that was negative for pancytokeratin and S-100. Later, a more comprehensive IHC panel including HMW-CK and p63 confirmed spindle cell SCC, but by this time, a delay in therapy had allowed the tumor to metastasize, which ultimately proved fatal to the patient.⁹  

In addition to incomplete IHC evaluation, accurate diagnosis of spindle cell tumors also may be obscured by inadequate tumor sampling. The cells of AFX tumors often are well circumscribed and dermally based, and an excisional biopsy is the preferred biopsy procedure for AFX. A tumor invading into subcutaneous tissue or into lymphovascular or perineural structures suggests a more aggressive, poorly differentiated spindle cell neoplasm.^1,3 For example, the tumor cells of malignant fibrous histiocytoma, which belongs to the undifferentiated pleomorphic sarcoma group, may appear identical to those of AFX on histology, and the 2 tumors display similar IHC profiles.³ Malignant fibrous histiocytoma, however, extends into the subcutaneous space and portends a notably worse prognosis compared to AFX. Malignant fibrous histiocytoma tumors therefore require more aggressive treatment strategies such as external beam radiation therapy, whereas AFX can be safely treated with surgical removal alone. In our patient, complete visualization of tumor margins solidified the diagnosis of AFX and spared our patient from unnecessary radiation therapy. Overall, AFX has a good prognosis and metastasis is rare, particularly when good margin control is achieved.¹⁰ 

Our case highlights the importance of clinicopathologic correlation, including appropriate IHC analysis and adequate tumor sampling in the diagnostic workup of a pleomorphic spindle cell neoplasm. Although these tumors are well studied, their notable degree of clinical and histologic heterogeneity may pose a diagnostic challenge to even experienced dermatologists and require careful consideration of the potential pitfalls in diagnosis.  

The Diagnosis: Atypical Fibroxanthoma  

Shave biopsy showed the superficial aspect of a highly cellular tumor composed of pleomorphic spindle cells exhibiting storiform growth and increased mitotic activity (Figure 1). The tumor stained positive for factor XIIIa, CD163, CD68, and smooth muscle actin (mild), and negative for high-molecular-weight cytokeratin (HMW-CK), p63, S-100, and melan-A. Subsequent excision with 0.5-cm margins was performed, and histopathology showed a well-circumscribed tumor contained within the dermis with a histologic scar at the outer margin (Figure 2). There was no lymphovascular or perineural invasion by tumor cells. Re-excision with 0.3-cm margins demonstrated no residual scar or tumor, and external radiation was deferred due to clear surgical margins.  

Atypical fibroxanthoma (AFX) belongs to a group of spindle cell neoplasms that can be diagnostically challenging, as they often lack specific morphologic features on examination or routine histology. These neoplasms--of which the differential includes malignant fibrous histiocytoma, spindle cell squamous cell carcinoma (SCC), desmoplastic melanoma, and leiomyosarcoma--may each appear as a rapidly enlarging solitary plaque or nodule on sun-damaged skin on the head and neck or less commonly on the trunk, arms, or legs. Histologically, the cells of AFX exhibit notable pleomorphism with frequent atypical mitotic figures and nonspecific surrounding dermal changes. Subcutaneous and lymphovascular or perineural invasion of tumor cells can point away from the diagnosis of AFX; however, these features are likely to be missed in small superficial shave biopsies.^1,2 Therefore, immunohistochemistry (IHC) and adequate tumor sampling are essential in the accurate diagnosis of AFX and other spindle cell neoplasms.  

Several IHC markers have been employed in differentiating AFX from other spindle cell neoplasms.^3-8 Positive stains for AFX include factor XIIIa (10%-25%), vimentin (>99%), CD10 (95%-100%), procollagen (87%), CD99 (35%-73%), CD163 (37%-79%), smooth muscle actin (50%), CD68 (>50%), and CD31 (43%). Other stains, such as HMW-CK, S-100, p63, desmin, CD34, and melan-A, typically are negative in AFX but are actively expressed in other pleomorphic spindle cell tumors. The Table summarizes the utility of these various markers in narrowing the differential diagnosis of a spindle cell lesion. Selection of an appropriate panel of IHC markers is critical for accurate diagnosis of AFX and exclusion of more aggressive, poorly differentiated spindle cell neoplasms. Key IHC markers include S-100 (negative in AFX; positive in desmoplastic melanoma), HMW-CK (negative in AFX; positive in spindle cell SCC), and p63 (negative in AFX; positive in spindle cell SCC). Benoit et al⁹ reported a case of a poorly differentiated spindle cell SCC misdiagnosed as AFX based on a limited IHC panel that was negative for pancytokeratin and S-100. Later, a more comprehensive IHC panel including HMW-CK and p63 confirmed spindle cell SCC, but by this time, a delay in therapy had allowed the tumor to metastasize, which ultimately proved fatal to the patient.⁹  

In addition to incomplete IHC evaluation, accurate diagnosis of spindle cell tumors also may be obscured by inadequate tumor sampling. The cells of AFX tumors often are well circumscribed and dermally based, and an excisional biopsy is the preferred biopsy procedure for AFX. A tumor invading into subcutaneous tissue or into lymphovascular or perineural structures suggests a more aggressive, poorly differentiated spindle cell neoplasm.^1,3 For example, the tumor cells of malignant fibrous histiocytoma, which belongs to the undifferentiated pleomorphic sarcoma group, may appear identical to those of AFX on histology, and the 2 tumors display similar IHC profiles.³ Malignant fibrous histiocytoma, however, extends into the subcutaneous space and portends a notably worse prognosis compared to AFX. Malignant fibrous histiocytoma tumors therefore require more aggressive treatment strategies such as external beam radiation therapy, whereas AFX can be safely treated with surgical removal alone. In our patient, complete visualization of tumor margins solidified the diagnosis of AFX and spared our patient from unnecessary radiation therapy. Overall, AFX has a good prognosis and metastasis is rare, particularly when good margin control is achieved.¹⁰ 

Our case highlights the importance of clinicopathologic correlation, including appropriate IHC analysis and adequate tumor sampling in the diagnostic workup of a pleomorphic spindle cell neoplasm. Although these tumors are well studied, their notable degree of clinical and histologic heterogeneity may pose a diagnostic challenge to even experienced dermatologists and require careful consideration of the potential pitfalls in diagnosis.  

The Diagnosis: Wells Syndrome 

Histopathologic examination of the biopsy demonstrated overlying acanthosis, focal spongiosis, and exocytosis. There also was proliferation and thickening of superficial capillaries and papillary fibrosis (Figure, A). There was a mixed interstitial and perivascular inflammatory infiltrate consisting of lymphocytes, histiocytes, plasma cells, and eosinophils (Figure, A and B). Occasional flame figures were identified (Figure, C). 

Wells syndrome, also known as eosinophilic cellulitis, was first described in 1971 by Wells¹ as a recurrent granulomatous dermatitis with eosinophilia. Rarely reported worldwide, this chronic relapsing condition is characterized by a pronounced eosinophilic infiltrate of the dermis resembling urticaria or cellulitis.² The exact etiology has not been elucidated; however, links to certain medications, vaccines, exaggerated arthropod reactions, infections, and malignancies have been documented.³  

Wells syndrome is a diagnosis of exclusion and lacks a predictable dermatologic presentation, thereby mandating focused clinical follow-up as well as correlation with histopathology findings. Although the classic histologic hallmark of Wells syndrome is scattered flame figures, this finding is not specific and can be found in other hypereosinophilic conditions.² Clinical manifestations most often consist of 2 distinct phases: an initial painful burning or pruritic sensation, followed by the development of erythematous and edematous dermal plaques that may heal with slight hyperpigmentation over 4 to 8 weeks. A case series of 19 patients demonstrated variants of Wells syndrome, with an annular granuloma-like appearance found primarily in adults and the signature plaque-type appearance predominating in children.⁴  

Acute urticaria is characterized by pruritic erythematous wheals secondary to a histamine-mediated response brought on by a variety of triggers, typically allergic and self-resolving within 24 hours. When such lesions last longer than 24 hours, biopsy should be performed to exclude urticarial vasculitis, which is characterized by a burning or painful sensation rather than pruritis, in addition to dermal neutrophilia and perivascular infiltrate on histology. Erythema migrans of Lyme disease begins at the site of a tick bite, evolving from a red macule to an expanding targetoid lesion and typically is not pruritic. Infectious cellulitis presents with warm, tender, and poorly defined erythematous patches; can progress rapidly; and is accompanied by systemic symptoms such as fevers, malaise, and lymphadenopathy.  

Best evidence favors the use of moderate- to high-dose corticosteroids as first-line treatment.⁵ The use of tumor necrosis factor blockers, various immunomodulating agents, and combination therapy with levocetirizine and hydroxyzine have demonstrated variable levels of efficacy, albeit often followed by high rates of relapse with drug discontinuation.⁶  

The Diagnosis: Wells Syndrome 

Histopathologic examination of the biopsy demonstrated overlying acanthosis, focal spongiosis, and exocytosis. There also was proliferation and thickening of superficial capillaries and papillary fibrosis (Figure, A). There was a mixed interstitial and perivascular inflammatory infiltrate consisting of lymphocytes, histiocytes, plasma cells, and eosinophils (Figure, A and B). Occasional flame figures were identified (Figure, C). 

Wells syndrome, also known as eosinophilic cellulitis, was first described in 1971 by Wells¹ as a recurrent granulomatous dermatitis with eosinophilia. Rarely reported worldwide, this chronic relapsing condition is characterized by a pronounced eosinophilic infiltrate of the dermis resembling urticaria or cellulitis.² The exact etiology has not been elucidated; however, links to certain medications, vaccines, exaggerated arthropod reactions, infections, and malignancies have been documented.³  

Wells syndrome is a diagnosis of exclusion and lacks a predictable dermatologic presentation, thereby mandating focused clinical follow-up as well as correlation with histopathology findings. Although the classic histologic hallmark of Wells syndrome is scattered flame figures, this finding is not specific and can be found in other hypereosinophilic conditions.² Clinical manifestations most often consist of 2 distinct phases: an initial painful burning or pruritic sensation, followed by the development of erythematous and edematous dermal plaques that may heal with slight hyperpigmentation over 4 to 8 weeks. A case series of 19 patients demonstrated variants of Wells syndrome, with an annular granuloma-like appearance found primarily in adults and the signature plaque-type appearance predominating in children.⁴  

Acute urticaria is characterized by pruritic erythematous wheals secondary to a histamine-mediated response brought on by a variety of triggers, typically allergic and self-resolving within 24 hours. When such lesions last longer than 24 hours, biopsy should be performed to exclude urticarial vasculitis, which is characterized by a burning or painful sensation rather than pruritis, in addition to dermal neutrophilia and perivascular infiltrate on histology. Erythema migrans of Lyme disease begins at the site of a tick bite, evolving from a red macule to an expanding targetoid lesion and typically is not pruritic. Infectious cellulitis presents with warm, tender, and poorly defined erythematous patches; can progress rapidly; and is accompanied by systemic symptoms such as fevers, malaise, and lymphadenopathy.  

Best evidence favors the use of moderate- to high-dose corticosteroids as first-line treatment.⁵ The use of tumor necrosis factor blockers, various immunomodulating agents, and combination therapy with levocetirizine and hydroxyzine have demonstrated variable levels of efficacy, albeit often followed by high rates of relapse with drug discontinuation.⁶  

The Diagnosis: Wells Syndrome 

Histopathologic examination of the biopsy demonstrated overlying acanthosis, focal spongiosis, and exocytosis. There also was proliferation and thickening of superficial capillaries and papillary fibrosis (Figure, A). There was a mixed interstitial and perivascular inflammatory infiltrate consisting of lymphocytes, histiocytes, plasma cells, and eosinophils (Figure, A and B). Occasional flame figures were identified (Figure, C). 

Wells syndrome, also known as eosinophilic cellulitis, was first described in 1971 by Wells¹ as a recurrent granulomatous dermatitis with eosinophilia. Rarely reported worldwide, this chronic relapsing condition is characterized by a pronounced eosinophilic infiltrate of the dermis resembling urticaria or cellulitis.² The exact etiology has not been elucidated; however, links to certain medications, vaccines, exaggerated arthropod reactions, infections, and malignancies have been documented.³  

Wells syndrome is a diagnosis of exclusion and lacks a predictable dermatologic presentation, thereby mandating focused clinical follow-up as well as correlation with histopathology findings. Although the classic histologic hallmark of Wells syndrome is scattered flame figures, this finding is not specific and can be found in other hypereosinophilic conditions.² Clinical manifestations most often consist of 2 distinct phases: an initial painful burning or pruritic sensation, followed by the development of erythematous and edematous dermal plaques that may heal with slight hyperpigmentation over 4 to 8 weeks. A case series of 19 patients demonstrated variants of Wells syndrome, with an annular granuloma-like appearance found primarily in adults and the signature plaque-type appearance predominating in children.⁴  

Acute urticaria is characterized by pruritic erythematous wheals secondary to a histamine-mediated response brought on by a variety of triggers, typically allergic and self-resolving within 24 hours. When such lesions last longer than 24 hours, biopsy should be performed to exclude urticarial vasculitis, which is characterized by a burning or painful sensation rather than pruritis, in addition to dermal neutrophilia and perivascular infiltrate on histology. Erythema migrans of Lyme disease begins at the site of a tick bite, evolving from a red macule to an expanding targetoid lesion and typically is not pruritic. Infectious cellulitis presents with warm, tender, and poorly defined erythematous patches; can progress rapidly; and is accompanied by systemic symptoms such as fevers, malaise, and lymphadenopathy.  

Best evidence favors the use of moderate- to high-dose corticosteroids as first-line treatment.⁵ The use of tumor necrosis factor blockers, various immunomodulating agents, and combination therapy with levocetirizine and hydroxyzine have demonstrated variable levels of efficacy, albeit often followed by high rates of relapse with drug discontinuation.⁶