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The Diagnosis: Necrolytic Acral Erythema

Histopathologic analysis of a biopsy specimen from the right leg revealed an erosion with parakeratosis containing neutrophils and marked spongiosis favoring the upper layer of the epidermis with focal individual necrotic keratinocytes. In addition, there was a lymphocytic and neutrophilic exocytosis with edema of the papillary dermal papillae, mild papillary dermal fibrosis, and a mild perivascular lymphocytic infiltrate with neutrophils and occasional eosinophils. Clinicopathologic correlation led to a diagnosis of necrolytic acral erythema (NAE).

The patient was prescribed clobetasol propionate ointment 0.05% and oral zinc sulfate 220 mg twice daily but was initially noncompliant with the topical corticosteroid regimen. He did, however, initiate zinc supplementation, which was later increased to 220 mg 3 times daily. At 3-month follow-up, the lesions had nearly completely cleared (Figure) and the serum zinc level was within reference range at 81 μg/dL.

Necrolytic acral erythema is a rare dermatosis that was first described in 1996 by el Darouti and Abu el Ela¹ in a series of 7 Egyptian patients. Since then, most of the cases have reported concomitant hepatitis C virus (HCV) infection.² Necrolytic acral erythema classically presents with symmetric, well-defined, hyperkeratotic plaques in an acral distribution, typically on the dorsal aspect of the feet.^2,3 Lesions may involve the dorsal aspect of the toes and the lower legs, with less common involvement of the elbows, hands, and buttocks. Patients often report pruritus and/or burning.³

Abdallah et al⁴ proposed several stages of NAE development with erythematous papules with dusky eroded centers progressing to marginated, erythematous to violaceous, lichenified plaques. Over time, these lesions tend to thin with progressive hyperpigmentation.

Histologically, early findings of NAE include acanthosis with epidermal spongiosis and upper dermal perivascular dermatitis. Over time, lesions may exhibit psoriasiform hyperplasia with papillomatosis and parakeratosis, epidermal pallor, subcorneal pustules, vascular ectasia, papillary dermal inflammation, and necrotic keratinocytes. Minimal to moderate acanthosis with an inflammatory infiltrate may be observed later in disease progression.⁵

The differential diagnosis of NAE includes many benign inflammatory skin diseases. Given the acral/extensor distribution of hyperkeratotic lesions and psoriasiform pattern on histopathology, NAE initially may be misdiagnosed as psoriasis. Unlike psoriasis, however, NAE rarely involves palmoplantar skin or nails⁴ and may respond dramatically to treatment with zinc supplementation.^6,7 Necrolytic acral erythema also may be confused with other necrolytic erythemas, including necrolytic migratory erythema, acrodermatitis enteropathica, and pellagra. A deficiency of biotin or essential fatty acids also may mimic NAE. Necrolytic acral erythema can be distinguished from these entities based on its characteristic appearance and distribution, along with comorbid HCV infection.^2-4

Several reports of NAE have revealed an associated zinc deficiency.^2,8 The underlying pathophysiology of zinc deficiency in NAE has not been elucidated but is thought to be related to HCV infection.² Clinical improvement has been reported with zinc supplementation in patients with NAE at dosages of 220 mg twice daily, even in those with initial serum zinc levels within reference range.^6,7 Our patient was observed to have a low serum zinc level that dramatically improved with oral supplementation.

The recognition of this uncommon entity is critical for dermatologists and dermatopathologists, as NAE has been proposed as an early cutaneous marker of HCV and may prompt the initial diagnosis of HCV.^1-10 The severity of NAE has even been linked to HCV severity.^1,8 Treatment of HCV has cleared NAE in several cases,^4,10 implicating the virus in its pathogenesis. A proper workup for liver dysfunction and follow-up with an appropriate health care provider for HCV treatment is crucial. Our patient was encouraged to follow up with the hepatology department, as he had not been evaluated in several years.

The Diagnosis: Necrolytic Acral Erythema

Histopathologic analysis of a biopsy specimen from the right leg revealed an erosion with parakeratosis containing neutrophils and marked spongiosis favoring the upper layer of the epidermis with focal individual necrotic keratinocytes. In addition, there was a lymphocytic and neutrophilic exocytosis with edema of the papillary dermal papillae, mild papillary dermal fibrosis, and a mild perivascular lymphocytic infiltrate with neutrophils and occasional eosinophils. Clinicopathologic correlation led to a diagnosis of necrolytic acral erythema (NAE).

The patient was prescribed clobetasol propionate ointment 0.05% and oral zinc sulfate 220 mg twice daily but was initially noncompliant with the topical corticosteroid regimen. He did, however, initiate zinc supplementation, which was later increased to 220 mg 3 times daily. At 3-month follow-up, the lesions had nearly completely cleared (Figure) and the serum zinc level was within reference range at 81 μg/dL.

Necrolytic acral erythema is a rare dermatosis that was first described in 1996 by el Darouti and Abu el Ela¹ in a series of 7 Egyptian patients. Since then, most of the cases have reported concomitant hepatitis C virus (HCV) infection.² Necrolytic acral erythema classically presents with symmetric, well-defined, hyperkeratotic plaques in an acral distribution, typically on the dorsal aspect of the feet.^2,3 Lesions may involve the dorsal aspect of the toes and the lower legs, with less common involvement of the elbows, hands, and buttocks. Patients often report pruritus and/or burning.³

Abdallah et al⁴ proposed several stages of NAE development with erythematous papules with dusky eroded centers progressing to marginated, erythematous to violaceous, lichenified plaques. Over time, these lesions tend to thin with progressive hyperpigmentation.

Histologically, early findings of NAE include acanthosis with epidermal spongiosis and upper dermal perivascular dermatitis. Over time, lesions may exhibit psoriasiform hyperplasia with papillomatosis and parakeratosis, epidermal pallor, subcorneal pustules, vascular ectasia, papillary dermal inflammation, and necrotic keratinocytes. Minimal to moderate acanthosis with an inflammatory infiltrate may be observed later in disease progression.⁵

The differential diagnosis of NAE includes many benign inflammatory skin diseases. Given the acral/extensor distribution of hyperkeratotic lesions and psoriasiform pattern on histopathology, NAE initially may be misdiagnosed as psoriasis. Unlike psoriasis, however, NAE rarely involves palmoplantar skin or nails⁴ and may respond dramatically to treatment with zinc supplementation.^6,7 Necrolytic acral erythema also may be confused with other necrolytic erythemas, including necrolytic migratory erythema, acrodermatitis enteropathica, and pellagra. A deficiency of biotin or essential fatty acids also may mimic NAE. Necrolytic acral erythema can be distinguished from these entities based on its characteristic appearance and distribution, along with comorbid HCV infection.^2-4

Several reports of NAE have revealed an associated zinc deficiency.^2,8 The underlying pathophysiology of zinc deficiency in NAE has not been elucidated but is thought to be related to HCV infection.² Clinical improvement has been reported with zinc supplementation in patients with NAE at dosages of 220 mg twice daily, even in those with initial serum zinc levels within reference range.^6,7 Our patient was observed to have a low serum zinc level that dramatically improved with oral supplementation.

The recognition of this uncommon entity is critical for dermatologists and dermatopathologists, as NAE has been proposed as an early cutaneous marker of HCV and may prompt the initial diagnosis of HCV.^1-10 The severity of NAE has even been linked to HCV severity.^1,8 Treatment of HCV has cleared NAE in several cases,^4,10 implicating the virus in its pathogenesis. A proper workup for liver dysfunction and follow-up with an appropriate health care provider for HCV treatment is crucial. Our patient was encouraged to follow up with the hepatology department, as he had not been evaluated in several years.

The Diagnosis: Necrolytic Acral Erythema

Histopathologic analysis of a biopsy specimen from the right leg revealed an erosion with parakeratosis containing neutrophils and marked spongiosis favoring the upper layer of the epidermis with focal individual necrotic keratinocytes. In addition, there was a lymphocytic and neutrophilic exocytosis with edema of the papillary dermal papillae, mild papillary dermal fibrosis, and a mild perivascular lymphocytic infiltrate with neutrophils and occasional eosinophils. Clinicopathologic correlation led to a diagnosis of necrolytic acral erythema (NAE).

The patient was prescribed clobetasol propionate ointment 0.05% and oral zinc sulfate 220 mg twice daily but was initially noncompliant with the topical corticosteroid regimen. He did, however, initiate zinc supplementation, which was later increased to 220 mg 3 times daily. At 3-month follow-up, the lesions had nearly completely cleared (Figure) and the serum zinc level was within reference range at 81 μg/dL.

Necrolytic acral erythema is a rare dermatosis that was first described in 1996 by el Darouti and Abu el Ela¹ in a series of 7 Egyptian patients. Since then, most of the cases have reported concomitant hepatitis C virus (HCV) infection.² Necrolytic acral erythema classically presents with symmetric, well-defined, hyperkeratotic plaques in an acral distribution, typically on the dorsal aspect of the feet.^2,3 Lesions may involve the dorsal aspect of the toes and the lower legs, with less common involvement of the elbows, hands, and buttocks. Patients often report pruritus and/or burning.³

Abdallah et al⁴ proposed several stages of NAE development with erythematous papules with dusky eroded centers progressing to marginated, erythematous to violaceous, lichenified plaques. Over time, these lesions tend to thin with progressive hyperpigmentation.

Histologically, early findings of NAE include acanthosis with epidermal spongiosis and upper dermal perivascular dermatitis. Over time, lesions may exhibit psoriasiform hyperplasia with papillomatosis and parakeratosis, epidermal pallor, subcorneal pustules, vascular ectasia, papillary dermal inflammation, and necrotic keratinocytes. Minimal to moderate acanthosis with an inflammatory infiltrate may be observed later in disease progression.⁵

The differential diagnosis of NAE includes many benign inflammatory skin diseases. Given the acral/extensor distribution of hyperkeratotic lesions and psoriasiform pattern on histopathology, NAE initially may be misdiagnosed as psoriasis. Unlike psoriasis, however, NAE rarely involves palmoplantar skin or nails⁴ and may respond dramatically to treatment with zinc supplementation.^6,7 Necrolytic acral erythema also may be confused with other necrolytic erythemas, including necrolytic migratory erythema, acrodermatitis enteropathica, and pellagra. A deficiency of biotin or essential fatty acids also may mimic NAE. Necrolytic acral erythema can be distinguished from these entities based on its characteristic appearance and distribution, along with comorbid HCV infection.^2-4

Several reports of NAE have revealed an associated zinc deficiency.^2,8 The underlying pathophysiology of zinc deficiency in NAE has not been elucidated but is thought to be related to HCV infection.² Clinical improvement has been reported with zinc supplementation in patients with NAE at dosages of 220 mg twice daily, even in those with initial serum zinc levels within reference range.^6,7 Our patient was observed to have a low serum zinc level that dramatically improved with oral supplementation.

The recognition of this uncommon entity is critical for dermatologists and dermatopathologists, as NAE has been proposed as an early cutaneous marker of HCV and may prompt the initial diagnosis of HCV.^1-10 The severity of NAE has even been linked to HCV severity.^1,8 Treatment of HCV has cleared NAE in several cases,^4,10 implicating the virus in its pathogenesis. A proper workup for liver dysfunction and follow-up with an appropriate health care provider for HCV treatment is crucial. Our patient was encouraged to follow up with the hepatology department, as he had not been evaluated in several years.

The Diagnosis: Irritated Seborrheic Keratosis

Biopsies of one of the protruding papules and the underlying plaque were performed. The specimen from the papule showed hyperkeratosis, acanthosis, papillomatosis, and a flattened dermoepidermal junction with demarcated horizontal margin, which demonstrated apparent upward growth of the epidermis. Moderate lymphocytic infiltration in the upper dermis also was observed (Figure, A). The histologic findings of the plaque showed acanthosis, several pseudohorn cysts, hyperpigmentation of the basal layer, and a horizontal demarcation of the dermoepidermal junction (Figure, B).

Seborrheic keratosis is the most common benign epidermal tumor of the skin with variable appearance.¹ It usually begins with well-circumscribed, dull, flat, tan or brown patches that then grow into waxy verrucous papules.¹ There are many clinicopathologic variants of SK such as common SK, stucco keratosis, and dermatosis papulosa nigra in clinical variation, as well as acanthotic, hyperkeratotic, clonal, reticulated, irritated, and melanoacanthoma subtypes based on histological variation.^2,3

Seborrheic keratosis is a tumor of keratinocytic origin. Although genetics, sun exposure,⁴ and human papillomavirus infection⁵ are thought to be causative factors, the precise etiology of SK is unknown.¹

The histology of SK shows monotonous basaloid tumor cells without atypia. It generally is comprised of focal acanthosis and papillomatosis with a sharp flat base. Intraepithelial horn pseudocysts are notable features of SK and increased melanin often is seen.^2,6

Irritated SK is a histologic variant of SK that has been mechanically or chemically irritated or is involved in immunologic responses. Histologically, the dermis underlying an SK lesion filled with a dense lymphocytic infiltration is characteristic.^1,2

For symptomatic or cosmetically undesirable lesions, complete removal of the lesion is the preferred treatment. Cryotherapy, electrodesiccation followed by curettage, curettage followed by desiccation, laser ablation, and surgical excision are effective treatments.¹

The Diagnosis: Irritated Seborrheic Keratosis

Biopsies of one of the protruding papules and the underlying plaque were performed. The specimen from the papule showed hyperkeratosis, acanthosis, papillomatosis, and a flattened dermoepidermal junction with demarcated horizontal margin, which demonstrated apparent upward growth of the epidermis. Moderate lymphocytic infiltration in the upper dermis also was observed (Figure, A). The histologic findings of the plaque showed acanthosis, several pseudohorn cysts, hyperpigmentation of the basal layer, and a horizontal demarcation of the dermoepidermal junction (Figure, B).

Seborrheic keratosis is the most common benign epidermal tumor of the skin with variable appearance.¹ It usually begins with well-circumscribed, dull, flat, tan or brown patches that then grow into waxy verrucous papules.¹ There are many clinicopathologic variants of SK such as common SK, stucco keratosis, and dermatosis papulosa nigra in clinical variation, as well as acanthotic, hyperkeratotic, clonal, reticulated, irritated, and melanoacanthoma subtypes based on histological variation.^2,3

Seborrheic keratosis is a tumor of keratinocytic origin. Although genetics, sun exposure,⁴ and human papillomavirus infection⁵ are thought to be causative factors, the precise etiology of SK is unknown.¹

The histology of SK shows monotonous basaloid tumor cells without atypia. It generally is comprised of focal acanthosis and papillomatosis with a sharp flat base. Intraepithelial horn pseudocysts are notable features of SK and increased melanin often is seen.^2,6

Irritated SK is a histologic variant of SK that has been mechanically or chemically irritated or is involved in immunologic responses. Histologically, the dermis underlying an SK lesion filled with a dense lymphocytic infiltration is characteristic.^1,2

For symptomatic or cosmetically undesirable lesions, complete removal of the lesion is the preferred treatment. Cryotherapy, electrodesiccation followed by curettage, curettage followed by desiccation, laser ablation, and surgical excision are effective treatments.¹

The Diagnosis: Irritated Seborrheic Keratosis

Biopsies of one of the protruding papules and the underlying plaque were performed. The specimen from the papule showed hyperkeratosis, acanthosis, papillomatosis, and a flattened dermoepidermal junction with demarcated horizontal margin, which demonstrated apparent upward growth of the epidermis. Moderate lymphocytic infiltration in the upper dermis also was observed (Figure, A). The histologic findings of the plaque showed acanthosis, several pseudohorn cysts, hyperpigmentation of the basal layer, and a horizontal demarcation of the dermoepidermal junction (Figure, B).

Seborrheic keratosis is the most common benign epidermal tumor of the skin with variable appearance.¹ It usually begins with well-circumscribed, dull, flat, tan or brown patches that then grow into waxy verrucous papules.¹ There are many clinicopathologic variants of SK such as common SK, stucco keratosis, and dermatosis papulosa nigra in clinical variation, as well as acanthotic, hyperkeratotic, clonal, reticulated, irritated, and melanoacanthoma subtypes based on histological variation.^2,3

Seborrheic keratosis is a tumor of keratinocytic origin. Although genetics, sun exposure,⁴ and human papillomavirus infection⁵ are thought to be causative factors, the precise etiology of SK is unknown.¹

The histology of SK shows monotonous basaloid tumor cells without atypia. It generally is comprised of focal acanthosis and papillomatosis with a sharp flat base. Intraepithelial horn pseudocysts are notable features of SK and increased melanin often is seen.^2,6

Irritated SK is a histologic variant of SK that has been mechanically or chemically irritated or is involved in immunologic responses. Histologically, the dermis underlying an SK lesion filled with a dense lymphocytic infiltration is characteristic.^1,2

For symptomatic or cosmetically undesirable lesions, complete removal of the lesion is the preferred treatment. Cryotherapy, electrodesiccation followed by curettage, curettage followed by desiccation, laser ablation, and surgical excision are effective treatments.¹

Linear Basal Cell Carcinoma

On examination, the lesion was suspected to be a nevocellular nevus, foreign body granuloma, or venous lake; however, a skin biopsy specimen from the lesion on the left wrist revealed a tumor mass of basaloid cells, peripheral palisading arrangement, and scattered pigment granules (Figure 1). Tumor cells were negative for S-100 protein staining. These findings were consistent with a diagnosis of linear basal cell carcinoma (BCC). The lesion was removed by simple excision with primary closure of the wound. The surgical margins were free of tumor cells. The lesion had not recurred at 6-month follow-up. The patient was subsequently lost to follow-up.

Basal cell carcinoma presents with diverse clinical features, and several morphologic and histologic variants have been reported.¹ Linear BCC was described as a distinct clinical entity in 1985 by Lewis² in a 73-year-old man with a 20-mm linear pigmented lesion on the left cheek. Linear BCC often is not recognized or categorized as such by clinicians, as some may think that linear BCC is not a distinct entity but rather is one of the diverse clinical features of BCC.³ Linear BCC is believed to have specific clinical and histologic features and can be regarded as a distinct entity.⁴ Mavrikakis et al⁵ objectively defined linear BCC as a lesion that appeared to extend preferentially in one direction, resulting in a lesion with relatively straight borders and a length much greater than the width (3:1 ratio). Our patient presented with a linearly curved lesion, which is a rare feature of BCC.

Linear BCC occurs in equal proportions in men and women aged 40 to 87 years. More than 92% of reported patients were older than 60 years.⁶ The most common site for linear BCC is the periocular area, with the majority of lesions occurring on the cheek or lower eyelid. The second most common site is the neck, followed by the trunk, lower face, and inguinal skin fold.^3,5

The mechanism of linearity has been speculated. The majority of the reported cases of linear BCC have no history of trauma.⁷ However, focal trauma has been assumed to be a risk factor for the development of linear BCC, so the possibility that the Köbner phenomenon may be related to its linear pattern has been proposed.⁸ The Köbner phenomenon can be implicated in our case, as there was a history of surgery, which resulted in a scar.

Menzies⁹ described dermoscopic features of pigmented BCC and stated that the diagnosis of pigmented BCC required the presence of 1 or more of the following 6 positive features: large blue-gray ovoid nests; multiple blue-gray globules; maple leaf–like areas; spoke wheel areas; ulceration; and arborizing treelike vessels. In our case, there were multiple blue-gray globules and a streak that resembled ginseng (Figure 2).

Linear BCC is an uncommon morphological variant that requires clinical recognition. Our case was unique because of the ginsenglike streak on dermoscopy and possible association with a prior trauma.

Linear Basal Cell Carcinoma

On examination, the lesion was suspected to be a nevocellular nevus, foreign body granuloma, or venous lake; however, a skin biopsy specimen from the lesion on the left wrist revealed a tumor mass of basaloid cells, peripheral palisading arrangement, and scattered pigment granules (Figure 1). Tumor cells were negative for S-100 protein staining. These findings were consistent with a diagnosis of linear basal cell carcinoma (BCC). The lesion was removed by simple excision with primary closure of the wound. The surgical margins were free of tumor cells. The lesion had not recurred at 6-month follow-up. The patient was subsequently lost to follow-up.

Basal cell carcinoma presents with diverse clinical features, and several morphologic and histologic variants have been reported.¹ Linear BCC was described as a distinct clinical entity in 1985 by Lewis² in a 73-year-old man with a 20-mm linear pigmented lesion on the left cheek. Linear BCC often is not recognized or categorized as such by clinicians, as some may think that linear BCC is not a distinct entity but rather is one of the diverse clinical features of BCC.³ Linear BCC is believed to have specific clinical and histologic features and can be regarded as a distinct entity.⁴ Mavrikakis et al⁵ objectively defined linear BCC as a lesion that appeared to extend preferentially in one direction, resulting in a lesion with relatively straight borders and a length much greater than the width (3:1 ratio). Our patient presented with a linearly curved lesion, which is a rare feature of BCC.

Linear BCC occurs in equal proportions in men and women aged 40 to 87 years. More than 92% of reported patients were older than 60 years.⁶ The most common site for linear BCC is the periocular area, with the majority of lesions occurring on the cheek or lower eyelid. The second most common site is the neck, followed by the trunk, lower face, and inguinal skin fold.^3,5

The mechanism of linearity has been speculated. The majority of the reported cases of linear BCC have no history of trauma.⁷ However, focal trauma has been assumed to be a risk factor for the development of linear BCC, so the possibility that the Köbner phenomenon may be related to its linear pattern has been proposed.⁸ The Köbner phenomenon can be implicated in our case, as there was a history of surgery, which resulted in a scar.

Menzies⁹ described dermoscopic features of pigmented BCC and stated that the diagnosis of pigmented BCC required the presence of 1 or more of the following 6 positive features: large blue-gray ovoid nests; multiple blue-gray globules; maple leaf–like areas; spoke wheel areas; ulceration; and arborizing treelike vessels. In our case, there were multiple blue-gray globules and a streak that resembled ginseng (Figure 2).

Linear BCC is an uncommon morphological variant that requires clinical recognition. Our case was unique because of the ginsenglike streak on dermoscopy and possible association with a prior trauma.

Linear Basal Cell Carcinoma

On examination, the lesion was suspected to be a nevocellular nevus, foreign body granuloma, or venous lake; however, a skin biopsy specimen from the lesion on the left wrist revealed a tumor mass of basaloid cells, peripheral palisading arrangement, and scattered pigment granules (Figure 1). Tumor cells were negative for S-100 protein staining. These findings were consistent with a diagnosis of linear basal cell carcinoma (BCC). The lesion was removed by simple excision with primary closure of the wound. The surgical margins were free of tumor cells. The lesion had not recurred at 6-month follow-up. The patient was subsequently lost to follow-up.

Basal cell carcinoma presents with diverse clinical features, and several morphologic and histologic variants have been reported.¹ Linear BCC was described as a distinct clinical entity in 1985 by Lewis² in a 73-year-old man with a 20-mm linear pigmented lesion on the left cheek. Linear BCC often is not recognized or categorized as such by clinicians, as some may think that linear BCC is not a distinct entity but rather is one of the diverse clinical features of BCC.³ Linear BCC is believed to have specific clinical and histologic features and can be regarded as a distinct entity.⁴ Mavrikakis et al⁵ objectively defined linear BCC as a lesion that appeared to extend preferentially in one direction, resulting in a lesion with relatively straight borders and a length much greater than the width (3:1 ratio). Our patient presented with a linearly curved lesion, which is a rare feature of BCC.

Linear BCC occurs in equal proportions in men and women aged 40 to 87 years. More than 92% of reported patients were older than 60 years.⁶ The most common site for linear BCC is the periocular area, with the majority of lesions occurring on the cheek or lower eyelid. The second most common site is the neck, followed by the trunk, lower face, and inguinal skin fold.^3,5

The mechanism of linearity has been speculated. The majority of the reported cases of linear BCC have no history of trauma.⁷ However, focal trauma has been assumed to be a risk factor for the development of linear BCC, so the possibility that the Köbner phenomenon may be related to its linear pattern has been proposed.⁸ The Köbner phenomenon can be implicated in our case, as there was a history of surgery, which resulted in a scar.

Menzies⁹ described dermoscopic features of pigmented BCC and stated that the diagnosis of pigmented BCC required the presence of 1 or more of the following 6 positive features: large blue-gray ovoid nests; multiple blue-gray globules; maple leaf–like areas; spoke wheel areas; ulceration; and arborizing treelike vessels. In our case, there were multiple blue-gray globules and a streak that resembled ginseng (Figure 2).

Linear BCC is an uncommon morphological variant that requires clinical recognition. Our case was unique because of the ginsenglike streak on dermoscopy and possible association with a prior trauma.

The Diagnosis: Primary Cutaneous Mucinous Carcinoma

Primary cutaneous mucinous carcinoma is a rare tumor of the sweat glands that was first reported in 1952 by Lennox et al.¹ These tumors are slow growing and have a predilection for the head and neck, with the eyelid being the most commonly reported location.² In general, they present as erythematous asymptomatic nodules measuring less than 7 cm in diameter.^2-4 Primary cutaneous mucinous carcinoma tends to have a good prognosis with complete resection, but cases of metastasis and recurrence have been reported.² Although there is no standard of care, treatment typically consists of surgical management, as the tumors are nonresponsive to chemotherapy or radiation.⁴ Kamalpour et al² compared outcomes for Mohs micrographic surgery versus standard excision, the former showing a lower percentage of poor outcomes. Of note, there were fewer cases treated with Mohs surgery in this study; only more recently reported cases have been treated with Mohs surgery.

Histologically, primary cutaneous mucinous carcinoma is composed of cords, tubules, and lobules of epithelial cells floating in large pools of basophilic mucin, separated by thin fibrovascular septa.⁵ It can be difficult to distinguish a primary tumor from a mucinous carcinoma metastasis with histology alone, especially on the breasts and in the gastrointestinal tract. Immunohistochemistry can be helpful in determining the origin of the tumor. A homologue of p53, p63 expressed in basal and myoepithelial cells of the skin can aid in the confirmation of a primary tumor when present.^6,7 Negative staining for cytokeratin 20 and positive staining for cytokeratin 7 also are helpful in distinguishing a primary cutaneous mucinous carcinoma from a gastrointestinal tract metastasis.^4,8

In our patient, no other symptoms were present that raised concern for an internal malignancy. Findings that supported a primary versus metastatic tumor included the clinicopathologic findings (Figure) as well as positive p63, cytokeratin 7, and negative cytokeratin 20 staining. The initial standard excision had tumor cells within 1 mm of the specimen margin; thus, a subsequent wider reexcision was performed. Reexcision was negative for tumor cells. Close follow-up with a primary care physician was recommended, with emphasis on colon and breast cancer screening. A follow-up mammogram was negative for breast cancer.

The Diagnosis: Primary Cutaneous Mucinous Carcinoma

Primary cutaneous mucinous carcinoma is a rare tumor of the sweat glands that was first reported in 1952 by Lennox et al.¹ These tumors are slow growing and have a predilection for the head and neck, with the eyelid being the most commonly reported location.² In general, they present as erythematous asymptomatic nodules measuring less than 7 cm in diameter.^2-4 Primary cutaneous mucinous carcinoma tends to have a good prognosis with complete resection, but cases of metastasis and recurrence have been reported.² Although there is no standard of care, treatment typically consists of surgical management, as the tumors are nonresponsive to chemotherapy or radiation.⁴ Kamalpour et al² compared outcomes for Mohs micrographic surgery versus standard excision, the former showing a lower percentage of poor outcomes. Of note, there were fewer cases treated with Mohs surgery in this study; only more recently reported cases have been treated with Mohs surgery.

Histologically, primary cutaneous mucinous carcinoma is composed of cords, tubules, and lobules of epithelial cells floating in large pools of basophilic mucin, separated by thin fibrovascular septa.⁵ It can be difficult to distinguish a primary tumor from a mucinous carcinoma metastasis with histology alone, especially on the breasts and in the gastrointestinal tract. Immunohistochemistry can be helpful in determining the origin of the tumor. A homologue of p53, p63 expressed in basal and myoepithelial cells of the skin can aid in the confirmation of a primary tumor when present.^6,7 Negative staining for cytokeratin 20 and positive staining for cytokeratin 7 also are helpful in distinguishing a primary cutaneous mucinous carcinoma from a gastrointestinal tract metastasis.^4,8

In our patient, no other symptoms were present that raised concern for an internal malignancy. Findings that supported a primary versus metastatic tumor included the clinicopathologic findings (Figure) as well as positive p63, cytokeratin 7, and negative cytokeratin 20 staining. The initial standard excision had tumor cells within 1 mm of the specimen margin; thus, a subsequent wider reexcision was performed. Reexcision was negative for tumor cells. Close follow-up with a primary care physician was recommended, with emphasis on colon and breast cancer screening. A follow-up mammogram was negative for breast cancer.

The Diagnosis: Primary Cutaneous Mucinous Carcinoma

Primary cutaneous mucinous carcinoma is a rare tumor of the sweat glands that was first reported in 1952 by Lennox et al.¹ These tumors are slow growing and have a predilection for the head and neck, with the eyelid being the most commonly reported location.² In general, they present as erythematous asymptomatic nodules measuring less than 7 cm in diameter.^2-4 Primary cutaneous mucinous carcinoma tends to have a good prognosis with complete resection, but cases of metastasis and recurrence have been reported.² Although there is no standard of care, treatment typically consists of surgical management, as the tumors are nonresponsive to chemotherapy or radiation.⁴ Kamalpour et al² compared outcomes for Mohs micrographic surgery versus standard excision, the former showing a lower percentage of poor outcomes. Of note, there were fewer cases treated with Mohs surgery in this study; only more recently reported cases have been treated with Mohs surgery.

Histologically, primary cutaneous mucinous carcinoma is composed of cords, tubules, and lobules of epithelial cells floating in large pools of basophilic mucin, separated by thin fibrovascular septa.⁵ It can be difficult to distinguish a primary tumor from a mucinous carcinoma metastasis with histology alone, especially on the breasts and in the gastrointestinal tract. Immunohistochemistry can be helpful in determining the origin of the tumor. A homologue of p53, p63 expressed in basal and myoepithelial cells of the skin can aid in the confirmation of a primary tumor when present.^6,7 Negative staining for cytokeratin 20 and positive staining for cytokeratin 7 also are helpful in distinguishing a primary cutaneous mucinous carcinoma from a gastrointestinal tract metastasis.^4,8

In our patient, no other symptoms were present that raised concern for an internal malignancy. Findings that supported a primary versus metastatic tumor included the clinicopathologic findings (Figure) as well as positive p63, cytokeratin 7, and negative cytokeratin 20 staining. The initial standard excision had tumor cells within 1 mm of the specimen margin; thus, a subsequent wider reexcision was performed. Reexcision was negative for tumor cells. Close follow-up with a primary care physician was recommended, with emphasis on colon and breast cancer screening. A follow-up mammogram was negative for breast cancer.

The Diagnosis: Eccrine Angiomatous Hamartoma

Given the progression of symptoms 3 months prior to presentation, an excisional biopsy was performed (Figure 1). Hematoxylin and eosin staining showed prominent eccrine sweat glands and vessels surrounded by superficially located adipose tissue in the mid and deep dermis (Figure 2).

Eccrine angiomatous hamartoma (EAH) is an uncommon benign tumor typically located on the arms and legs or trunk. It is usually solitary, though cases with multiple lesions have been reported.^1,2 Most cases are diagnosed in childhood as either congenital or acquired lesions. However, EAHs can develop in adulthood and have been described in patients up to 70 years of age.³ The median age of diagnosis is 10 years,² indicating that EAH is primarily a pediatric tumor. There is no gender predilection.

Approximately 35% to 66% of patients report pain, pruritus, or hyperhidrosis associated with EAHs, though this incidence may be overrepresented because patients tend to present when the lesions become symptomatic.^2-5 The pain is attributed to nerve fibers infiltrating the tumor. Hypertrichosis also has been described and is thought to be due to hair follicles within the hamartoma.

Histologically, EAHs are characterized by normal-appearing eccrine glands mingled with venules and capillaries. Additional variable pathologic findings include lipomatous, pilar, lymphatic, or mucinous features.² Other vascular anomalies such as hemangiomas or arteriovenous malformations occasionally have been described in association with EAH. The vessels stain for ulex europaeus 1 and factor VIII. Eccrine glands stain for S-100 protein, carcinoembryonic antigen, epithelial membrane antigen, and cytokeratin CAM 5.2. In light of a publication proposing that EAH is a lymphatic proliferation,⁶ a D2-40 stain was performed on the specimen and was negative. 

Eccrine angiomatous hamartoma has been reported to grow mainly during childhood, puberty, or pregnancy, presumably due to hormonal influences.⁷ There are few reports of EAH enlarging in middle-aged adults, and even fewer without pain during the growth phase. It is unclear what triggered the growth in our otherwise healthy postmenopausal patient.

Eccrine angiomatous hamartoma does not have malignant potential and thus treatment is optional and based on relief of symptoms. Simple excision of the EAH usually is curative, but recurrences can occur.⁴ Botulinum toxin also has been used to treat hyperhidrosis in tumors that are too large for resection. Treatment with lasers such as the pulsed dye laser and Nd:YAG laser has not been successful.⁸ A case of spontaneous regression has been reported.¹

Liposuction was considered in our patient given the substantial adipose tissue on biopsy. The patient ultimately declined treatment. This case highlights that EAH can present in adulthood and should be considered in the differential diagnosis of an enlarging but otherwise asymptomatic vascular tumor.

The Diagnosis: Eccrine Angiomatous Hamartoma

Given the progression of symptoms 3 months prior to presentation, an excisional biopsy was performed (Figure 1). Hematoxylin and eosin staining showed prominent eccrine sweat glands and vessels surrounded by superficially located adipose tissue in the mid and deep dermis (Figure 2).

Eccrine angiomatous hamartoma (EAH) is an uncommon benign tumor typically located on the arms and legs or trunk. It is usually solitary, though cases with multiple lesions have been reported.^1,2 Most cases are diagnosed in childhood as either congenital or acquired lesions. However, EAHs can develop in adulthood and have been described in patients up to 70 years of age.³ The median age of diagnosis is 10 years,² indicating that EAH is primarily a pediatric tumor. There is no gender predilection.

Approximately 35% to 66% of patients report pain, pruritus, or hyperhidrosis associated with EAHs, though this incidence may be overrepresented because patients tend to present when the lesions become symptomatic.^2-5 The pain is attributed to nerve fibers infiltrating the tumor. Hypertrichosis also has been described and is thought to be due to hair follicles within the hamartoma.

Histologically, EAHs are characterized by normal-appearing eccrine glands mingled with venules and capillaries. Additional variable pathologic findings include lipomatous, pilar, lymphatic, or mucinous features.² Other vascular anomalies such as hemangiomas or arteriovenous malformations occasionally have been described in association with EAH. The vessels stain for ulex europaeus 1 and factor VIII. Eccrine glands stain for S-100 protein, carcinoembryonic antigen, epithelial membrane antigen, and cytokeratin CAM 5.2. In light of a publication proposing that EAH is a lymphatic proliferation,⁶ a D2-40 stain was performed on the specimen and was negative. 

Eccrine angiomatous hamartoma has been reported to grow mainly during childhood, puberty, or pregnancy, presumably due to hormonal influences.⁷ There are few reports of EAH enlarging in middle-aged adults, and even fewer without pain during the growth phase. It is unclear what triggered the growth in our otherwise healthy postmenopausal patient.

Eccrine angiomatous hamartoma does not have malignant potential and thus treatment is optional and based on relief of symptoms. Simple excision of the EAH usually is curative, but recurrences can occur.⁴ Botulinum toxin also has been used to treat hyperhidrosis in tumors that are too large for resection. Treatment with lasers such as the pulsed dye laser and Nd:YAG laser has not been successful.⁸ A case of spontaneous regression has been reported.¹

Liposuction was considered in our patient given the substantial adipose tissue on biopsy. The patient ultimately declined treatment. This case highlights that EAH can present in adulthood and should be considered in the differential diagnosis of an enlarging but otherwise asymptomatic vascular tumor.

The Diagnosis: Eccrine Angiomatous Hamartoma

Given the progression of symptoms 3 months prior to presentation, an excisional biopsy was performed (Figure 1). Hematoxylin and eosin staining showed prominent eccrine sweat glands and vessels surrounded by superficially located adipose tissue in the mid and deep dermis (Figure 2).

Eccrine angiomatous hamartoma (EAH) is an uncommon benign tumor typically located on the arms and legs or trunk. It is usually solitary, though cases with multiple lesions have been reported.^1,2 Most cases are diagnosed in childhood as either congenital or acquired lesions. However, EAHs can develop in adulthood and have been described in patients up to 70 years of age.³ The median age of diagnosis is 10 years,² indicating that EAH is primarily a pediatric tumor. There is no gender predilection.

Approximately 35% to 66% of patients report pain, pruritus, or hyperhidrosis associated with EAHs, though this incidence may be overrepresented because patients tend to present when the lesions become symptomatic.^2-5 The pain is attributed to nerve fibers infiltrating the tumor. Hypertrichosis also has been described and is thought to be due to hair follicles within the hamartoma.

Histologically, EAHs are characterized by normal-appearing eccrine glands mingled with venules and capillaries. Additional variable pathologic findings include lipomatous, pilar, lymphatic, or mucinous features.² Other vascular anomalies such as hemangiomas or arteriovenous malformations occasionally have been described in association with EAH. The vessels stain for ulex europaeus 1 and factor VIII. Eccrine glands stain for S-100 protein, carcinoembryonic antigen, epithelial membrane antigen, and cytokeratin CAM 5.2. In light of a publication proposing that EAH is a lymphatic proliferation,⁶ a D2-40 stain was performed on the specimen and was negative. 

Eccrine angiomatous hamartoma has been reported to grow mainly during childhood, puberty, or pregnancy, presumably due to hormonal influences.⁷ There are few reports of EAH enlarging in middle-aged adults, and even fewer without pain during the growth phase. It is unclear what triggered the growth in our otherwise healthy postmenopausal patient.

Eccrine angiomatous hamartoma does not have malignant potential and thus treatment is optional and based on relief of symptoms. Simple excision of the EAH usually is curative, but recurrences can occur.⁴ Botulinum toxin also has been used to treat hyperhidrosis in tumors that are too large for resection. Treatment with lasers such as the pulsed dye laser and Nd:YAG laser has not been successful.⁸ A case of spontaneous regression has been reported.¹

Liposuction was considered in our patient given the substantial adipose tissue on biopsy. The patient ultimately declined treatment. This case highlights that EAH can present in adulthood and should be considered in the differential diagnosis of an enlarging but otherwise asymptomatic vascular tumor.

The Diagnosis: Granulomatous Slack Skin Disease

Initial biopsy revealed a lichenoid lymphohistiocytic infiltrate with scattered epidermotropism, papillary dermal sclerosis, and lymphocyte atypia (Figure 1). A repeat biopsy showed a lichenoid granulomatous infiltrate with histiocytes and rare giant cells, superficially located in the dermis, without a deeper dense infiltration. Focal lymphocytic epidermotropism also was present (Figure 2). The infiltrate was CD3⁺CD4⁺ with a minority of cells also staining for CD8. An elastin stain demonstrated diminished elastin fibers in the superficial dermis. A clonal T-cell receptor gene rearrangement was identified by polymerase chain reaction. One group of pink and brown papules was present on the dorsal aspect of the right foot (Figure 3). A biopsy of this area showed similar findings. The patient was treated with a trial of carmustine 20-mg% ointment over the following year with some improvement of the mild pruritus but without notable change in the clinical findings.

Granulomatous slack skin disease (GSSD) is a rare form of mycosis fungoides–type cutaneous T-cell lymphoma. It usually presents as well-demarcated, atrophic, poikilodermatous patches and plaques with a predilection for the inguinal and axillary regions.¹ The affected areas tend to be asymptomatic and enlarge gradually over years to become pendulous with lax skin and wrinkles. In contrast to other forms of cutaneous T-cell lymphoma, extracutaneous spread is rare. The disease shows a slow progression over many years and by itself is not life threatening. However, affected patients have a risk for developing secondary lymphoproliferative neoplasms, which have been documented in approximately 50% of reported cases.² These lymphoproliferative neoplasms may arise concurrently, precede, or follow the development of GSSD lesions. Hodgkin lymphoma, seen in 33% of cases, is the most common association, with others being non-Hodgkin lymphoma, mycosis fungoides, acute myeloid leukemia, and Langerhans cell histiocytosis.^1-3

Histologically, GSSD is characterized by a dense, dermal, granulomatous proliferation of atypical T lymphocytes with scattered multinucleated giant cells.^1,4 There is a loss of elastin fibers in the infiltrated areas, and occasional elastophagocytosis can be seen.^1,2,4 Immunoprofiling of the infiltrate has shown CD3⁺CD4⁺CD45RO⁺ T-helper cells with occasional loss of CD5 and CD7.³ A clonal T-cell receptor rearrangement of the g and b genes frequently is described.^1,4,5

At this time no treatment has been found to be reliably curative. Varying success in treating GSSD has been achieved with topical nitrogen mustard, carmustine, topical and systemic corticosteroids, psoralen plus UVA, radiotherapy, azathioprine, IFN-g, and combinations of these agents.^1-3,6-9 Excision of the diseased skin has been performed for cosmetically or functionally disturbing lesions, but in all but one case the lesions recurred within months.^1,10 A consistently reliable treatment of GSSD has not been established; treatment should be tailored to the individual patient.

The Diagnosis: Granulomatous Slack Skin Disease

Initial biopsy revealed a lichenoid lymphohistiocytic infiltrate with scattered epidermotropism, papillary dermal sclerosis, and lymphocyte atypia (Figure 1). A repeat biopsy showed a lichenoid granulomatous infiltrate with histiocytes and rare giant cells, superficially located in the dermis, without a deeper dense infiltration. Focal lymphocytic epidermotropism also was present (Figure 2). The infiltrate was CD3⁺CD4⁺ with a minority of cells also staining for CD8. An elastin stain demonstrated diminished elastin fibers in the superficial dermis. A clonal T-cell receptor gene rearrangement was identified by polymerase chain reaction. One group of pink and brown papules was present on the dorsal aspect of the right foot (Figure 3). A biopsy of this area showed similar findings. The patient was treated with a trial of carmustine 20-mg% ointment over the following year with some improvement of the mild pruritus but without notable change in the clinical findings.

Granulomatous slack skin disease (GSSD) is a rare form of mycosis fungoides–type cutaneous T-cell lymphoma. It usually presents as well-demarcated, atrophic, poikilodermatous patches and plaques with a predilection for the inguinal and axillary regions.¹ The affected areas tend to be asymptomatic and enlarge gradually over years to become pendulous with lax skin and wrinkles. In contrast to other forms of cutaneous T-cell lymphoma, extracutaneous spread is rare. The disease shows a slow progression over many years and by itself is not life threatening. However, affected patients have a risk for developing secondary lymphoproliferative neoplasms, which have been documented in approximately 50% of reported cases.² These lymphoproliferative neoplasms may arise concurrently, precede, or follow the development of GSSD lesions. Hodgkin lymphoma, seen in 33% of cases, is the most common association, with others being non-Hodgkin lymphoma, mycosis fungoides, acute myeloid leukemia, and Langerhans cell histiocytosis.^1-3

Histologically, GSSD is characterized by a dense, dermal, granulomatous proliferation of atypical T lymphocytes with scattered multinucleated giant cells.^1,4 There is a loss of elastin fibers in the infiltrated areas, and occasional elastophagocytosis can be seen.^1,2,4 Immunoprofiling of the infiltrate has shown CD3⁺CD4⁺CD45RO⁺ T-helper cells with occasional loss of CD5 and CD7.³ A clonal T-cell receptor rearrangement of the g and b genes frequently is described.^1,4,5

At this time no treatment has been found to be reliably curative. Varying success in treating GSSD has been achieved with topical nitrogen mustard, carmustine, topical and systemic corticosteroids, psoralen plus UVA, radiotherapy, azathioprine, IFN-g, and combinations of these agents.^1-3,6-9 Excision of the diseased skin has been performed for cosmetically or functionally disturbing lesions, but in all but one case the lesions recurred within months.^1,10 A consistently reliable treatment of GSSD has not been established; treatment should be tailored to the individual patient.

The Diagnosis: Granulomatous Slack Skin Disease

Initial biopsy revealed a lichenoid lymphohistiocytic infiltrate with scattered epidermotropism, papillary dermal sclerosis, and lymphocyte atypia (Figure 1). A repeat biopsy showed a lichenoid granulomatous infiltrate with histiocytes and rare giant cells, superficially located in the dermis, without a deeper dense infiltration. Focal lymphocytic epidermotropism also was present (Figure 2). The infiltrate was CD3⁺CD4⁺ with a minority of cells also staining for CD8. An elastin stain demonstrated diminished elastin fibers in the superficial dermis. A clonal T-cell receptor gene rearrangement was identified by polymerase chain reaction. One group of pink and brown papules was present on the dorsal aspect of the right foot (Figure 3). A biopsy of this area showed similar findings. The patient was treated with a trial of carmustine 20-mg% ointment over the following year with some improvement of the mild pruritus but without notable change in the clinical findings.

Granulomatous slack skin disease (GSSD) is a rare form of mycosis fungoides–type cutaneous T-cell lymphoma. It usually presents as well-demarcated, atrophic, poikilodermatous patches and plaques with a predilection for the inguinal and axillary regions.¹ The affected areas tend to be asymptomatic and enlarge gradually over years to become pendulous with lax skin and wrinkles. In contrast to other forms of cutaneous T-cell lymphoma, extracutaneous spread is rare. The disease shows a slow progression over many years and by itself is not life threatening. However, affected patients have a risk for developing secondary lymphoproliferative neoplasms, which have been documented in approximately 50% of reported cases.² These lymphoproliferative neoplasms may arise concurrently, precede, or follow the development of GSSD lesions. Hodgkin lymphoma, seen in 33% of cases, is the most common association, with others being non-Hodgkin lymphoma, mycosis fungoides, acute myeloid leukemia, and Langerhans cell histiocytosis.^1-3

Histologically, GSSD is characterized by a dense, dermal, granulomatous proliferation of atypical T lymphocytes with scattered multinucleated giant cells.^1,4 There is a loss of elastin fibers in the infiltrated areas, and occasional elastophagocytosis can be seen.^1,2,4 Immunoprofiling of the infiltrate has shown CD3⁺CD4⁺CD45RO⁺ T-helper cells with occasional loss of CD5 and CD7.³ A clonal T-cell receptor rearrangement of the g and b genes frequently is described.^1,4,5

At this time no treatment has been found to be reliably curative. Varying success in treating GSSD has been achieved with topical nitrogen mustard, carmustine, topical and systemic corticosteroids, psoralen plus UVA, radiotherapy, azathioprine, IFN-g, and combinations of these agents.^1-3,6-9 Excision of the diseased skin has been performed for cosmetically or functionally disturbing lesions, but in all but one case the lesions recurred within months.^1,10 A consistently reliable treatment of GSSD has not been established; treatment should be tailored to the individual patient.

The Diagnosis: Fibroepithelioma of Pinkus

Fibroepithelioma of Pinkus (FeP) was first described in 1953¹ and was thought to be premalignant as evidenced by the proposed name premalignant fibroepithelial tumor of the skin. This neoplasm now is largely believed to represent a rare form of basal cell carcinoma (BCC). Typical presentation is a smooth, flesh-colored or pink plaque or nodule.² Fibroepithelioma of Pinkus has a predilection for the lumbosacral back, though the groin also has been reported as a common site of incidence.^1,3 Similar to other BCCs, it is seen in older individuals, typically those older than 50 years.^3,4

Clinical diagnosis of FeP can be difficult. The differential diagnosis of FeP can include acrochordon, amelanotic melanoma, compound nevus, hemangioma, neurofibroma, nevus sebaceous, pyogenic granuloma, and seborrheic keratosis.⁵ Dermoscopic evaluation can aid in the diagnosis. A vascular network composed of fine arborizing vessels with or without dotted vessels and white streaks are characteristic findings of FeP. Patients with pigment also demonstrate structureless gray-brown areas and gray-blue dots.⁶

Biopsy with subsequent histopathologic evaluation confirms the diagnosis of FeP. The characteristic microscopic findings of thin eosinophilic epithelial strands with eccrine ducts anastomosing in an abundant fibromyxoid stroma with collections of basophilic cells located at the ends of the epithelial strands were demonstrated in our patient’s histopathologic specimen (Figure). The histologic appearance is similar to syringofibroadenoma of Mascaro. Recognition of basaloid nests, which often demonstrate retraction, and mitotic activity can differentiate FeP from syringofibroadenoma of Mascaro.⁷

Treatment of FeP is largely the same as other BCCs including destruction by electrodesiccation and curettage or complete removal by surgical excision. Several studies have demonstrated effective treatment of nonaggressive BCCs with curettage alone and subjectively reported improved cosmesis compared to electrodesiccation and curettage.^8-10 Although methyl aminolevulinate photodynamic therapy has demonstrated some therapeutic efficacy for superficial and nodular BCCs,¹¹ a case report utilizing the same modality for FeP did not provide adequate response.¹² However, adequate data are not available to assess potential use of this less invasive therapy.

The Diagnosis: Fibroepithelioma of Pinkus

Fibroepithelioma of Pinkus (FeP) was first described in 1953¹ and was thought to be premalignant as evidenced by the proposed name premalignant fibroepithelial tumor of the skin. This neoplasm now is largely believed to represent a rare form of basal cell carcinoma (BCC). Typical presentation is a smooth, flesh-colored or pink plaque or nodule.² Fibroepithelioma of Pinkus has a predilection for the lumbosacral back, though the groin also has been reported as a common site of incidence.^1,3 Similar to other BCCs, it is seen in older individuals, typically those older than 50 years.^3,4

Clinical diagnosis of FeP can be difficult. The differential diagnosis of FeP can include acrochordon, amelanotic melanoma, compound nevus, hemangioma, neurofibroma, nevus sebaceous, pyogenic granuloma, and seborrheic keratosis.⁵ Dermoscopic evaluation can aid in the diagnosis. A vascular network composed of fine arborizing vessels with or without dotted vessels and white streaks are characteristic findings of FeP. Patients with pigment also demonstrate structureless gray-brown areas and gray-blue dots.⁶

Biopsy with subsequent histopathologic evaluation confirms the diagnosis of FeP. The characteristic microscopic findings of thin eosinophilic epithelial strands with eccrine ducts anastomosing in an abundant fibromyxoid stroma with collections of basophilic cells located at the ends of the epithelial strands were demonstrated in our patient’s histopathologic specimen (Figure). The histologic appearance is similar to syringofibroadenoma of Mascaro. Recognition of basaloid nests, which often demonstrate retraction, and mitotic activity can differentiate FeP from syringofibroadenoma of Mascaro.⁷

Treatment of FeP is largely the same as other BCCs including destruction by electrodesiccation and curettage or complete removal by surgical excision. Several studies have demonstrated effective treatment of nonaggressive BCCs with curettage alone and subjectively reported improved cosmesis compared to electrodesiccation and curettage.^8-10 Although methyl aminolevulinate photodynamic therapy has demonstrated some therapeutic efficacy for superficial and nodular BCCs,¹¹ a case report utilizing the same modality for FeP did not provide adequate response.¹² However, adequate data are not available to assess potential use of this less invasive therapy.

The Diagnosis: Fibroepithelioma of Pinkus

Fibroepithelioma of Pinkus (FeP) was first described in 1953¹ and was thought to be premalignant as evidenced by the proposed name premalignant fibroepithelial tumor of the skin. This neoplasm now is largely believed to represent a rare form of basal cell carcinoma (BCC). Typical presentation is a smooth, flesh-colored or pink plaque or nodule.² Fibroepithelioma of Pinkus has a predilection for the lumbosacral back, though the groin also has been reported as a common site of incidence.^1,3 Similar to other BCCs, it is seen in older individuals, typically those older than 50 years.^3,4

Clinical diagnosis of FeP can be difficult. The differential diagnosis of FeP can include acrochordon, amelanotic melanoma, compound nevus, hemangioma, neurofibroma, nevus sebaceous, pyogenic granuloma, and seborrheic keratosis.⁵ Dermoscopic evaluation can aid in the diagnosis. A vascular network composed of fine arborizing vessels with or without dotted vessels and white streaks are characteristic findings of FeP. Patients with pigment also demonstrate structureless gray-brown areas and gray-blue dots.⁶

Biopsy with subsequent histopathologic evaluation confirms the diagnosis of FeP. The characteristic microscopic findings of thin eosinophilic epithelial strands with eccrine ducts anastomosing in an abundant fibromyxoid stroma with collections of basophilic cells located at the ends of the epithelial strands were demonstrated in our patient’s histopathologic specimen (Figure). The histologic appearance is similar to syringofibroadenoma of Mascaro. Recognition of basaloid nests, which often demonstrate retraction, and mitotic activity can differentiate FeP from syringofibroadenoma of Mascaro.⁷

Treatment of FeP is largely the same as other BCCs including destruction by electrodesiccation and curettage or complete removal by surgical excision. Several studies have demonstrated effective treatment of nonaggressive BCCs with curettage alone and subjectively reported improved cosmesis compared to electrodesiccation and curettage.^8-10 Although methyl aminolevulinate photodynamic therapy has demonstrated some therapeutic efficacy for superficial and nodular BCCs,¹¹ a case report utilizing the same modality for FeP did not provide adequate response.¹² However, adequate data are not available to assess potential use of this less invasive therapy.

The Diagnosis: Primary Cutaneous Carcinosarcoma

A generous shave biopsy and debulking performed on the initial visit revealed an infiltrating tumor consisting of malignant epithelial and stromal components (Figure). The basaloid and squamoid epithelial cells were keratin positive. The stromal cells demonstrated positivity for CD10 but were keratin negative. The epithelial portion of the tumor was composed mostly of basaloid islands of cells with nuclear pleomorphism, scattered mitoses, and focal sebaceous differentiation. The mesenchymal portion of the tumor displayed florid pleomorphism and polymorphism, with many large atypical cells and proliferation. A diagnosis of primary cutaneous carcinosarcoma (PCC) was rendered. Head and neck computed tomography showed tumor penetration of less than 1 cm into scalp soft tissues with no involvement of the underlying bone. There was some evidence of swelling of the supragaleal soft tissues without indication of perineural spread. An 11-mm hyperlucent lower cervical lymph node on the left side that likely represented an incidental finding was noted. Surgical excision with margin evaluation was recommended, but the patient declined. He instead received radiation therapy to the left side of the posterior scalp with a total dose of 30 Gy at 6 Gy per fraction and 1 fraction daily. The patient was found to have a well-healed scar with no evidence of recurrence at 4-week follow-up and again at 5 months after radiation therapy.

A generous shave biopsy and debulking performed on the initial visit revealed an inflitrating tumor consisting on malignant epithelial and stromal components (A-C)(H&E; original magnifications ×10, ×20, and ×40, respectively).

Primary cutaneous carcinosarcoma is a rare biphasic neoplasm of unknown etiology that is characterized by the presence of both malignant epithelial and mesenchymal components.¹ Carcinosarcomas have been reported in both the male and female reproductive tracts, urinary tract, gastrointestinal tract, lungs, breasts, larynx, thymus, and thyroid but is uncommon as a primary neoplasm of the skin.² Epidermal PCC occurs with greater frequency in males than in females and typically presents in the eighth or ninth decades of life.³ These tumors tend to arise in sun-exposed regions, most commonly on the face and scalp.²

Morphologically, PCCs typically are exophytic growths that often feature surface ulceration and may or may not bleed upon palpation.⁴ Primary cutaneous carcinosarcomas may present as long-standing lesions that have undergone rapid transformation in the weeks preceding presentation.⁴ It is not uncommon for PCC lesions to carry the clinical diagnosis of squamous cell carcinoma, which suggests notable morphologic overlap between these entities. Histopathologically, PCC shows a basal cell carcinoma and/or a squamous cell carcinoma epithelial component intimately admixed with a sarcomatous component.⁵ The mesenchymal component of PCC typically resembles a superficial malignant fibrous histiocytoma characterized by pleomorphic nuclei and cytoplasm, necrosis, and an increased number of mitotic figures.² Immunohistochemistry can be beneficial in the diagnosis of PCC. A combination of p63 and AE1/AE3 stains can be used to confirm cells of epithelial origin. Staining with vimentin, CD10, or caldesmon can help to delineate the mesenchymal component of PCC.

Epidermal PCC most commonly affects elderly individuals with a history of extensive sun exposure. It has been suggested that p53 mutations due to UV damage are key in tumor formation for both epithelial and mesenchymal elements.⁵ Literature supports a monoclonal origin for the epithelial and mesenchymal components of this tumor; however, there is insufficient evidence.⁶ Surgical excision is the primary treatment modality for epidermal PCC, but adjuvant or substitutive radiotherapy has been used in some cases.⁴ The prognosis of PCC is notably better than its visceral counterpart due to early diagnosis and treatment of easily visible lesions. Epidermal PCC has a 70% 5-year disease-free survival rate, while adnexal PCC tends to occur in younger patients and has a 25% 5-year disease-free survival rate.³ Due to the rarity of reported cases and limited follow-up, the long-term prognosis for PCC remains unclear.

We report an unusual case of PCC on the scalp that was successfully treated with radiation therapy alone. This modality should be considered in patients with large tumors who refuse surgery or are not good surgical candidates.

The Diagnosis: Primary Cutaneous Carcinosarcoma

A generous shave biopsy and debulking performed on the initial visit revealed an infiltrating tumor consisting of malignant epithelial and stromal components (Figure). The basaloid and squamoid epithelial cells were keratin positive. The stromal cells demonstrated positivity for CD10 but were keratin negative. The epithelial portion of the tumor was composed mostly of basaloid islands of cells with nuclear pleomorphism, scattered mitoses, and focal sebaceous differentiation. The mesenchymal portion of the tumor displayed florid pleomorphism and polymorphism, with many large atypical cells and proliferation. A diagnosis of primary cutaneous carcinosarcoma (PCC) was rendered. Head and neck computed tomography showed tumor penetration of less than 1 cm into scalp soft tissues with no involvement of the underlying bone. There was some evidence of swelling of the supragaleal soft tissues without indication of perineural spread. An 11-mm hyperlucent lower cervical lymph node on the left side that likely represented an incidental finding was noted. Surgical excision with margin evaluation was recommended, but the patient declined. He instead received radiation therapy to the left side of the posterior scalp with a total dose of 30 Gy at 6 Gy per fraction and 1 fraction daily. The patient was found to have a well-healed scar with no evidence of recurrence at 4-week follow-up and again at 5 months after radiation therapy.

A generous shave biopsy and debulking performed on the initial visit revealed an inflitrating tumor consisting on malignant epithelial and stromal components (A-C)(H&E; original magnifications ×10, ×20, and ×40, respectively).

Primary cutaneous carcinosarcoma is a rare biphasic neoplasm of unknown etiology that is characterized by the presence of both malignant epithelial and mesenchymal components.¹ Carcinosarcomas have been reported in both the male and female reproductive tracts, urinary tract, gastrointestinal tract, lungs, breasts, larynx, thymus, and thyroid but is uncommon as a primary neoplasm of the skin.² Epidermal PCC occurs with greater frequency in males than in females and typically presents in the eighth or ninth decades of life.³ These tumors tend to arise in sun-exposed regions, most commonly on the face and scalp.²

Morphologically, PCCs typically are exophytic growths that often feature surface ulceration and may or may not bleed upon palpation.⁴ Primary cutaneous carcinosarcomas may present as long-standing lesions that have undergone rapid transformation in the weeks preceding presentation.⁴ It is not uncommon for PCC lesions to carry the clinical diagnosis of squamous cell carcinoma, which suggests notable morphologic overlap between these entities. Histopathologically, PCC shows a basal cell carcinoma and/or a squamous cell carcinoma epithelial component intimately admixed with a sarcomatous component.⁵ The mesenchymal component of PCC typically resembles a superficial malignant fibrous histiocytoma characterized by pleomorphic nuclei and cytoplasm, necrosis, and an increased number of mitotic figures.² Immunohistochemistry can be beneficial in the diagnosis of PCC. A combination of p63 and AE1/AE3 stains can be used to confirm cells of epithelial origin. Staining with vimentin, CD10, or caldesmon can help to delineate the mesenchymal component of PCC.

Epidermal PCC most commonly affects elderly individuals with a history of extensive sun exposure. It has been suggested that p53 mutations due to UV damage are key in tumor formation for both epithelial and mesenchymal elements.⁵ Literature supports a monoclonal origin for the epithelial and mesenchymal components of this tumor; however, there is insufficient evidence.⁶ Surgical excision is the primary treatment modality for epidermal PCC, but adjuvant or substitutive radiotherapy has been used in some cases.⁴ The prognosis of PCC is notably better than its visceral counterpart due to early diagnosis and treatment of easily visible lesions. Epidermal PCC has a 70% 5-year disease-free survival rate, while adnexal PCC tends to occur in younger patients and has a 25% 5-year disease-free survival rate.³ Due to the rarity of reported cases and limited follow-up, the long-term prognosis for PCC remains unclear.

We report an unusual case of PCC on the scalp that was successfully treated with radiation therapy alone. This modality should be considered in patients with large tumors who refuse surgery or are not good surgical candidates.

The Diagnosis: Primary Cutaneous Carcinosarcoma

A generous shave biopsy and debulking performed on the initial visit revealed an infiltrating tumor consisting of malignant epithelial and stromal components (Figure). The basaloid and squamoid epithelial cells were keratin positive. The stromal cells demonstrated positivity for CD10 but were keratin negative. The epithelial portion of the tumor was composed mostly of basaloid islands of cells with nuclear pleomorphism, scattered mitoses, and focal sebaceous differentiation. The mesenchymal portion of the tumor displayed florid pleomorphism and polymorphism, with many large atypical cells and proliferation. A diagnosis of primary cutaneous carcinosarcoma (PCC) was rendered. Head and neck computed tomography showed tumor penetration of less than 1 cm into scalp soft tissues with no involvement of the underlying bone. There was some evidence of swelling of the supragaleal soft tissues without indication of perineural spread. An 11-mm hyperlucent lower cervical lymph node on the left side that likely represented an incidental finding was noted. Surgical excision with margin evaluation was recommended, but the patient declined. He instead received radiation therapy to the left side of the posterior scalp with a total dose of 30 Gy at 6 Gy per fraction and 1 fraction daily. The patient was found to have a well-healed scar with no evidence of recurrence at 4-week follow-up and again at 5 months after radiation therapy.

A generous shave biopsy and debulking performed on the initial visit revealed an inflitrating tumor consisting on malignant epithelial and stromal components (A-C)(H&E; original magnifications ×10, ×20, and ×40, respectively).

Primary cutaneous carcinosarcoma is a rare biphasic neoplasm of unknown etiology that is characterized by the presence of both malignant epithelial and mesenchymal components.¹ Carcinosarcomas have been reported in both the male and female reproductive tracts, urinary tract, gastrointestinal tract, lungs, breasts, larynx, thymus, and thyroid but is uncommon as a primary neoplasm of the skin.² Epidermal PCC occurs with greater frequency in males than in females and typically presents in the eighth or ninth decades of life.³ These tumors tend to arise in sun-exposed regions, most commonly on the face and scalp.²

Morphologically, PCCs typically are exophytic growths that often feature surface ulceration and may or may not bleed upon palpation.⁴ Primary cutaneous carcinosarcomas may present as long-standing lesions that have undergone rapid transformation in the weeks preceding presentation.⁴ It is not uncommon for PCC lesions to carry the clinical diagnosis of squamous cell carcinoma, which suggests notable morphologic overlap between these entities. Histopathologically, PCC shows a basal cell carcinoma and/or a squamous cell carcinoma epithelial component intimately admixed with a sarcomatous component.⁵ The mesenchymal component of PCC typically resembles a superficial malignant fibrous histiocytoma characterized by pleomorphic nuclei and cytoplasm, necrosis, and an increased number of mitotic figures.² Immunohistochemistry can be beneficial in the diagnosis of PCC. A combination of p63 and AE1/AE3 stains can be used to confirm cells of epithelial origin. Staining with vimentin, CD10, or caldesmon can help to delineate the mesenchymal component of PCC.

Epidermal PCC most commonly affects elderly individuals with a history of extensive sun exposure. It has been suggested that p53 mutations due to UV damage are key in tumor formation for both epithelial and mesenchymal elements.⁵ Literature supports a monoclonal origin for the epithelial and mesenchymal components of this tumor; however, there is insufficient evidence.⁶ Surgical excision is the primary treatment modality for epidermal PCC, but adjuvant or substitutive radiotherapy has been used in some cases.⁴ The prognosis of PCC is notably better than its visceral counterpart due to early diagnosis and treatment of easily visible lesions. Epidermal PCC has a 70% 5-year disease-free survival rate, while adnexal PCC tends to occur in younger patients and has a 25% 5-year disease-free survival rate.³ Due to the rarity of reported cases and limited follow-up, the long-term prognosis for PCC remains unclear.

We report an unusual case of PCC on the scalp that was successfully treated with radiation therapy alone. This modality should be considered in patients with large tumors who refuse surgery or are not good surgical candidates.

The Diagnosis: Herpetic Glossitis

Oral lesions of the tongue are common during primary herpetic gingivostomatitis, though most primary oral herpes simplex virus (HSV) infections occur during childhood or early adulthood. Reactivation of HSV type 1 most commonly manifests as herpes labialis.¹ When recurrent HSV involves intraoral lesions, they are typically confined to the gingiva and palate, sparing the tongue.

Clinical presentation of herpetic glossitis varies. Recurrent herpetic glossitis has been described in immunocompromised patients, particularly those with hematologic malignancies and organ transplants.² In addition, immunocompromised and human immunodeficiency virus–infected patients may present with deep and/or broad ulcers. A case of herpes infection presenting with nodules on the tongue has been reported in Hodgkin disease.³ Herpetic geometric glossitis also has been described, which is a linear, crosshatched, or sharply angled branching with painful fissuring of the tongue. Herpetic geometric glossitis has been reported to occur in both immunocompetent and immunocompromised individuals.⁴ Tongue involvement during oral reactivation of HSV is exceedingly rare and the pathogenesis remains elusive, though one hypothesis proposes a protective role of salivary-specific IgA and lysozyme.⁵ Here, we report a case in which a patient developed similar lingual HSV lesions following recent immunosuppression.

The Diagnosis: Herpetic Glossitis

Oral lesions of the tongue are common during primary herpetic gingivostomatitis, though most primary oral herpes simplex virus (HSV) infections occur during childhood or early adulthood. Reactivation of HSV type 1 most commonly manifests as herpes labialis.¹ When recurrent HSV involves intraoral lesions, they are typically confined to the gingiva and palate, sparing the tongue.

Clinical presentation of herpetic glossitis varies. Recurrent herpetic glossitis has been described in immunocompromised patients, particularly those with hematologic malignancies and organ transplants.² In addition, immunocompromised and human immunodeficiency virus–infected patients may present with deep and/or broad ulcers. A case of herpes infection presenting with nodules on the tongue has been reported in Hodgkin disease.³ Herpetic geometric glossitis also has been described, which is a linear, crosshatched, or sharply angled branching with painful fissuring of the tongue. Herpetic geometric glossitis has been reported to occur in both immunocompetent and immunocompromised individuals.⁴ Tongue involvement during oral reactivation of HSV is exceedingly rare and the pathogenesis remains elusive, though one hypothesis proposes a protective role of salivary-specific IgA and lysozyme.⁵ Here, we report a case in which a patient developed similar lingual HSV lesions following recent immunosuppression.

The Diagnosis: Herpetic Glossitis

Oral lesions of the tongue are common during primary herpetic gingivostomatitis, though most primary oral herpes simplex virus (HSV) infections occur during childhood or early adulthood. Reactivation of HSV type 1 most commonly manifests as herpes labialis.¹ When recurrent HSV involves intraoral lesions, they are typically confined to the gingiva and palate, sparing the tongue.

Clinical presentation of herpetic glossitis varies. Recurrent herpetic glossitis has been described in immunocompromised patients, particularly those with hematologic malignancies and organ transplants.² In addition, immunocompromised and human immunodeficiency virus–infected patients may present with deep and/or broad ulcers. A case of herpes infection presenting with nodules on the tongue has been reported in Hodgkin disease.³ Herpetic geometric glossitis also has been described, which is a linear, crosshatched, or sharply angled branching with painful fissuring of the tongue. Herpetic geometric glossitis has been reported to occur in both immunocompetent and immunocompromised individuals.⁴ Tongue involvement during oral reactivation of HSV is exceedingly rare and the pathogenesis remains elusive, though one hypothesis proposes a protective role of salivary-specific IgA and lysozyme.⁵ Here, we report a case in which a patient developed similar lingual HSV lesions following recent immunosuppression.

The Diagnosis: Superficial Acral Fibromyxoma

Superficial acral fibromyxoma (SAF) was first described in 2001 by Fetsch et al.¹ Subsequently, the term digital fibromyxoma was proposed in 2012 by Hollmann et al² to describe a distinctive, slow-growing, soft-tissue tumor with a predilection for the periungual or subungual regions of the fingers and toes. The benign growth typically presents as a painless or tender nodule in middle-aged adults with a slight male predominance (1.3:1 ratio).^1,2 In a case series (N=124) described by Hollmann et al,² 9 of 25 patients (36%) who had imaging studies showed bone involvement by an erosive or lytic lesion. Reports of SAF with bone involvement also have been described in the radiologic and orthopedic surgery literature.^3,4 Radiographically, the soft-tissue invasion of the bone is demonstrated by scalloping on plain radiographs (Figure 1).³

Histologically, SAFs are moderately cellular with spindled or stellate fibroblastlike cells within a myxoid or collagenous matrix (Figure 2).¹ The vasculature is mildly accentuated and an increase in mast cells usually is observed. The nuclei have a low degree of atypia with few mitotic figures, and the stellate cells exhibit positive immunohistochemical staining for CD34 (Figure 3), epithelial membrane antigen, and CD99.¹ Hollmann et al² found that 66 of 95 tumors (69.5%) infiltrated the dermal collagen, 26 (27.4%) infiltrated fat, and 3 (3.2%) invaded bone. Of the 47 cases that were evaluated on follow-up, 10 tumors (21.3%) recurred locally (all near the nail unit of the fingers or toes) after a mean interval of 27 months. Although invasion of underlying tissues and recurrence of the tumor has been demonstrated, this growth is considered benign. The histologic differential diagnosis includes neurofibroma, myxoma, fibroma, low-grade fibromyxoid sarcoma, dermatofibroma, superficial angiomyxoma, and dermatofibrosarcoma protuberans.²

The primary treatment of SAF is local excision. The incidence of local recurrence found in the case series by Hollmann et al² was directly linked to positive margins after the first excision (10/47 [21.3%] recurrent lesions had positive margins). To date, there are no known reports of metastatic disease in SAF.² Our case manifested with a late recurrence of the tumor and bone involvement requiring surgical excision, which illustrates the role of adjuvant imaging and close follow-up following excision of any soft-tissue tumors of the fingers and toes that have been histologically confirmed as SAF, particularly those of the periungual region.

The Diagnosis: Superficial Acral Fibromyxoma

Superficial acral fibromyxoma (SAF) was first described in 2001 by Fetsch et al.¹ Subsequently, the term digital fibromyxoma was proposed in 2012 by Hollmann et al² to describe a distinctive, slow-growing, soft-tissue tumor with a predilection for the periungual or subungual regions of the fingers and toes. The benign growth typically presents as a painless or tender nodule in middle-aged adults with a slight male predominance (1.3:1 ratio).^1,2 In a case series (N=124) described by Hollmann et al,² 9 of 25 patients (36%) who had imaging studies showed bone involvement by an erosive or lytic lesion. Reports of SAF with bone involvement also have been described in the radiologic and orthopedic surgery literature.^3,4 Radiographically, the soft-tissue invasion of the bone is demonstrated by scalloping on plain radiographs (Figure 1).³

Histologically, SAFs are moderately cellular with spindled or stellate fibroblastlike cells within a myxoid or collagenous matrix (Figure 2).¹ The vasculature is mildly accentuated and an increase in mast cells usually is observed. The nuclei have a low degree of atypia with few mitotic figures, and the stellate cells exhibit positive immunohistochemical staining for CD34 (Figure 3), epithelial membrane antigen, and CD99.¹ Hollmann et al² found that 66 of 95 tumors (69.5%) infiltrated the dermal collagen, 26 (27.4%) infiltrated fat, and 3 (3.2%) invaded bone. Of the 47 cases that were evaluated on follow-up, 10 tumors (21.3%) recurred locally (all near the nail unit of the fingers or toes) after a mean interval of 27 months. Although invasion of underlying tissues and recurrence of the tumor has been demonstrated, this growth is considered benign. The histologic differential diagnosis includes neurofibroma, myxoma, fibroma, low-grade fibromyxoid sarcoma, dermatofibroma, superficial angiomyxoma, and dermatofibrosarcoma protuberans.²

The primary treatment of SAF is local excision. The incidence of local recurrence found in the case series by Hollmann et al² was directly linked to positive margins after the first excision (10/47 [21.3%] recurrent lesions had positive margins). To date, there are no known reports of metastatic disease in SAF.² Our case manifested with a late recurrence of the tumor and bone involvement requiring surgical excision, which illustrates the role of adjuvant imaging and close follow-up following excision of any soft-tissue tumors of the fingers and toes that have been histologically confirmed as SAF, particularly those of the periungual region.

The Diagnosis: Superficial Acral Fibromyxoma

Superficial acral fibromyxoma (SAF) was first described in 2001 by Fetsch et al.¹ Subsequently, the term digital fibromyxoma was proposed in 2012 by Hollmann et al² to describe a distinctive, slow-growing, soft-tissue tumor with a predilection for the periungual or subungual regions of the fingers and toes. The benign growth typically presents as a painless or tender nodule in middle-aged adults with a slight male predominance (1.3:1 ratio).^1,2 In a case series (N=124) described by Hollmann et al,² 9 of 25 patients (36%) who had imaging studies showed bone involvement by an erosive or lytic lesion. Reports of SAF with bone involvement also have been described in the radiologic and orthopedic surgery literature.^3,4 Radiographically, the soft-tissue invasion of the bone is demonstrated by scalloping on plain radiographs (Figure 1).³

Histologically, SAFs are moderately cellular with spindled or stellate fibroblastlike cells within a myxoid or collagenous matrix (Figure 2).¹ The vasculature is mildly accentuated and an increase in mast cells usually is observed. The nuclei have a low degree of atypia with few mitotic figures, and the stellate cells exhibit positive immunohistochemical staining for CD34 (Figure 3), epithelial membrane antigen, and CD99.¹ Hollmann et al² found that 66 of 95 tumors (69.5%) infiltrated the dermal collagen, 26 (27.4%) infiltrated fat, and 3 (3.2%) invaded bone. Of the 47 cases that were evaluated on follow-up, 10 tumors (21.3%) recurred locally (all near the nail unit of the fingers or toes) after a mean interval of 27 months. Although invasion of underlying tissues and recurrence of the tumor has been demonstrated, this growth is considered benign. The histologic differential diagnosis includes neurofibroma, myxoma, fibroma, low-grade fibromyxoid sarcoma, dermatofibroma, superficial angiomyxoma, and dermatofibrosarcoma protuberans.²

The primary treatment of SAF is local excision. The incidence of local recurrence found in the case series by Hollmann et al² was directly linked to positive margins after the first excision (10/47 [21.3%] recurrent lesions had positive margins). To date, there are no known reports of metastatic disease in SAF.² Our case manifested with a late recurrence of the tumor and bone involvement requiring surgical excision, which illustrates the role of adjuvant imaging and close follow-up following excision of any soft-tissue tumors of the fingers and toes that have been histologically confirmed as SAF, particularly those of the periungual region.