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Paclitaxel-induced papular eruption with ringed mitoses
P1503
P1505
Equivalent histologic findings in atypical nevi from patients with and without melanoma Alyssa Hoverson, DO, Mayo Clinic, Rochester, MN, United States; Roger Weenig, MPH, MD, Mayo Clinic, Rochester, MN, United States
Indeterminate cell histiocytosis: A case report and novel immunohistochemical finding Lonnie Hammonds, MD, Mayo Clinic Jacksonville, Jacksonville, FL, United States; John Snow, MD, Mayo Clinic Jacksonville, Jacksonville, FL, United States
Objective: To determine if individual atypical histologic features in melanocytic nevi predict melanoma risk, and if so, to quantify the magnitude of this risk. Methods: Four hundred thirty skin pathology slides with a histologic diagnosis of ‘‘atypia’’ were sequentially retrieved by patient identification number from 172 patients seen at the Mayo Clinic in Rochester, MN between 1992 and 2004. After blinding to clinical history and diagnosis, age, gender, and previous pathologic diagnosis, microscopic examination of all skin biopsies was performed and the presence or absence of 18 histologic features was recorded. The frequency of each ‘‘atypical’’ histologic feature in melanocytic nevi from patients with and without a history of melanoma was compared using a 2-tailed Pearson x2 analysis. P # .05 was considered statistically significant. Results: The frequency of each atypical histologic feature was similar in the melanocytic nevi obtained from patients with and without a history of cutaneous malignant melanoma. No statistically significant difference was observed for any feature by univariate or multivariate analysis. Two (0.5%) of the biopsies were interpreted as melanoma and were excluded from the analysis.
We present a case report of an 85-year-old male with indeterminate cell histiocytosis. During a routine skin cancer follow-up examination, a diffuse eruption of 2- to 3-mm, monomorphic, red-brown papules was noted. Biopsy revealed a dense histiocytic infiltrate in the upper dermis. The histiocytes exhibited abundant, periodic acideSchiff positive, eosinophilic cytoplasm. These cells stained positively for CD1a and S100 and negatively for CD68 and factor XIIIa. Interestingly, these cells were negative for Langerin. Electron microscopy did not demonstrate classic Birbeck granules within these cells. Based upon the clinical presentation, histopathology, and ultrastructural analysis, a diagnosis of indeterminate cell histiocytosis was made. This is an exceedingly rare variant of cutaneous histiocytosis which may be differentiated from Langerhans cell histiocytosis by three cardinal features: the lack of Birbeck granules on ultrastructural study, the absence of epidermotropism on histopathology, and the lack of extracutaneous involvement. The absence of Langerin staining in this disorder has not been previously reported but may also be characteristic. These cells typically express both Langerhans cell and monocyte/macrophage markers. It has been postulated that the indeterminate cell may represent an immature Langerhans cell or an indeterminate type of dendritic cell.
Conclusions: Atypical histologic features are identified with an equivalent frequency in patients with or without a history of melanoma. The findings in this study suggest that identification of ‘‘atypical’’ histologic features in an otherwise benign melanocytic nevus does not equate to increased risk for melanoma. Given that two (0.5%) of the lesions originally believed to represent atypical nevi were confirmed to be melanomas, these findings support the assertion that atypical nevi possess histologic features in common with melanoma. Furthermore, given that both of these melanomas were incomplete samples of larger pigment lesions, complete removal of all suspicious pigmented lesions at initial biopsy is recommended.
Commercial support: None identified.
Commercial support: None identified.
P1506 Can lesions present as rashes? A pathologist’s clue to the diagnosis Victoria Helen Smith, MD, Royal Liverpool & Broadgreen University Hospitals NHS Trust, Liverpool, Merseyside, United Kingdom; Paul D Yesudian, MBBCh, Countess of Chester Hospital NHS Foundation Trust, Chester, Cheshire, United Kingdom
P1504 Paclitaxel-induced papular eruption with ringed mitoses Mark Tusa, Texas A&M Health Science Center College of Medicine, Temple, TX, United States Abnormal mitotic figures may be seen histologicly in skin biopsies performed after the application of podophyllin and after the systemic administration of etoposide. We present an 85-year-old female who developed a scaly nonpruritic papular eruption on the forearms. The patient was receiving treatment for metastatic adenocarcinoma of an unknown primary with weekly paclitaxel. A biopsy of one of the papules demonstrated vacuolar degeneration with epidermal spongiosis, apoptosis, circular basal cell mitoses, and cellular atypia. Abnormal circular mitotic figures have been reported with use of laulimalide analogues, but not with paclitaxel. Laulimalide and paclitaxel are both potent microtubule stabilizers, but in vitro testing has shown that tumors resistant to paclitaxel may respond to laulimalide analogues. We discuss the unusual histologic features of the drug-related skin eruption, the potential etiology of circular mitotic figures, and review the literature regarding chemotherapy-induced mitotic figures. Commercial support: None identified.
AB74
J AM ACAD DERMATOL
An 86-year-old female presented with a 14-month history of an itchy expanding rash on the buttocks and a 12-month history of multiple keratotic lesions, predominantly on the head and neck. The latter resolved spontaneously with pitted scarring after 4 months, only to recur elsewhere. There was no history of skin cancer, exposure to tar, pitch, printing chemicals or arsenic, excessive sun, nor a relevant family history. On examination, multiple papules and nodules with keratotic centers were present on the face and scalp, with smaller lesions on the trunk and limbs. These lesions resembled keratoacanthomas, but adnexal tumors were also considered in the differential diagnosis. On the buttocks, there was an erythematous plaque with peripheral follicular hyperkeratosis. Differential diagnosis of lichen planus and mycosis fungoides were proffered. Surprisingly, histology from the buttock plaque revealed a focally acanthotic dyskeratotic squamous epithelium with irregular buds, suggestive of a squamous cell carcinoma. The histology from one of the facial lesions confirmed a keratoacanthoma (KA). A unifying diagnosis of multiple KAs coexisting with KA centrifugum marginatum (KCM) was made. Treatment with low dose acitretin (10 mg/day) for 3 months resolved the KCM. The KAs decreased in number and size and have been less symptomatic. Multiple KAs may present in different forms; the commonest is the Ferguson Smith type where multiple self-resolving lesions occur in young adults, often of Scottish descent. Sporadic cases have also been reported. Our patient had multiple KAs with another rare keratoacanthoma variant, KCM. The response to acitretin concurs with previous experience, although higher doses have been used in the past. Precisely why retinoids are effective for KAs is unknown; it may modulate terminal differentiation of epidermal cells, thereby inducing inhibition of keratinisation. Alternatively, it could also have an antikeratin effect. The lack of family history, late age of onset, occurrence of two rare variants of KAs, and the response to low doses of acitretin makes our patient unusual. One cannot underestimate the role of the pathologist in helping the clinician make this rare dual diagnosis. Commercial support: None identified.
MARCH 2009
P1505
Equivalent histologic findings in atypical nevi from patients with and without melanoma Alyssa Hoverson, DO, Mayo Clinic, Rochester, MN, United States; Roger Weenig, MPH, MD, Mayo Clinic, Rochester, MN, United States
Indeterminate cell histiocytosis: A case report and novel immunohistochemical finding Lonnie Hammonds, MD, Mayo Clinic Jacksonville, Jacksonville, FL, United States; John Snow, MD, Mayo Clinic Jacksonville, Jacksonville, FL, United States
Objective: To determine if individual atypical histologic features in melanocytic nevi predict melanoma risk, and if so, to quantify the magnitude of this risk. Methods: Four hundred thirty skin pathology slides with a histologic diagnosis of ‘‘atypia’’ were sequentially retrieved by patient identification number from 172 patients seen at the Mayo Clinic in Rochester, MN between 1992 and 2004. After blinding to clinical history and diagnosis, age, gender, and previous pathologic diagnosis, microscopic examination of all skin biopsies was performed and the presence or absence of 18 histologic features was recorded. The frequency of each ‘‘atypical’’ histologic feature in melanocytic nevi from patients with and without a history of melanoma was compared using a 2-tailed Pearson x2 analysis. P # .05 was considered statistically significant. Results: The frequency of each atypical histologic feature was similar in the melanocytic nevi obtained from patients with and without a history of cutaneous malignant melanoma. No statistically significant difference was observed for any feature by univariate or multivariate analysis. Two (0.5%) of the biopsies were interpreted as melanoma and were excluded from the analysis.
We present a case report of an 85-year-old male with indeterminate cell histiocytosis. During a routine skin cancer follow-up examination, a diffuse eruption of 2- to 3-mm, monomorphic, red-brown papules was noted. Biopsy revealed a dense histiocytic infiltrate in the upper dermis. The histiocytes exhibited abundant, periodic acideSchiff positive, eosinophilic cytoplasm. These cells stained positively for CD1a and S100 and negatively for CD68 and factor XIIIa. Interestingly, these cells were negative for Langerin. Electron microscopy did not demonstrate classic Birbeck granules within these cells. Based upon the clinical presentation, histopathology, and ultrastructural analysis, a diagnosis of indeterminate cell histiocytosis was made. This is an exceedingly rare variant of cutaneous histiocytosis which may be differentiated from Langerhans cell histiocytosis by three cardinal features: the lack of Birbeck granules on ultrastructural study, the absence of epidermotropism on histopathology, and the lack of extracutaneous involvement. The absence of Langerin staining in this disorder has not been previously reported but may also be characteristic. These cells typically express both Langerhans cell and monocyte/macrophage markers. It has been postulated that the indeterminate cell may represent an immature Langerhans cell or an indeterminate type of dendritic cell.
Conclusions: Atypical histologic features are identified with an equivalent frequency in patients with or without a history of melanoma. The findings in this study suggest that identification of ‘‘atypical’’ histologic features in an otherwise benign melanocytic nevus does not equate to increased risk for melanoma. Given that two (0.5%) of the lesions originally believed to represent atypical nevi were confirmed to be melanomas, these findings support the assertion that atypical nevi possess histologic features in common with melanoma. Furthermore, given that both of these melanomas were incomplete samples of larger pigment lesions, complete removal of all suspicious pigmented lesions at initial biopsy is recommended.
Commercial support: None identified.
Commercial support: None identified.
P1506 Can lesions present as rashes? A pathologist’s clue to the diagnosis Victoria Helen Smith, MD, Royal Liverpool & Broadgreen University Hospitals NHS Trust, Liverpool, Merseyside, United Kingdom; Paul D Yesudian, MBBCh, Countess of Chester Hospital NHS Foundation Trust, Chester, Cheshire, United Kingdom
P1504 Paclitaxel-induced papular eruption with ringed mitoses Mark Tusa, Texas A&M Health Science Center College of Medicine, Temple, TX, United States Abnormal mitotic figures may be seen histologicly in skin biopsies performed after the application of podophyllin and after the systemic administration of etoposide. We present an 85-year-old female who developed a scaly nonpruritic papular eruption on the forearms. The patient was receiving treatment for metastatic adenocarcinoma of an unknown primary with weekly paclitaxel. A biopsy of one of the papules demonstrated vacuolar degeneration with epidermal spongiosis, apoptosis, circular basal cell mitoses, and cellular atypia. Abnormal circular mitotic figures have been reported with use of laulimalide analogues, but not with paclitaxel. Laulimalide and paclitaxel are both potent microtubule stabilizers, but in vitro testing has shown that tumors resistant to paclitaxel may respond to laulimalide analogues. We discuss the unusual histologic features of the drug-related skin eruption, the potential etiology of circular mitotic figures, and review the literature regarding chemotherapy-induced mitotic figures. Commercial support: None identified.
AB74
J AM ACAD DERMATOL
An 86-year-old female presented with a 14-month history of an itchy expanding rash on the buttocks and a 12-month history of multiple keratotic lesions, predominantly on the head and neck. The latter resolved spontaneously with pitted scarring after 4 months, only to recur elsewhere. There was no history of skin cancer, exposure to tar, pitch, printing chemicals or arsenic, excessive sun, nor a relevant family history. On examination, multiple papules and nodules with keratotic centers were present on the face and scalp, with smaller lesions on the trunk and limbs. These lesions resembled keratoacanthomas, but adnexal tumors were also considered in the differential diagnosis. On the buttocks, there was an erythematous plaque with peripheral follicular hyperkeratosis. Differential diagnosis of lichen planus and mycosis fungoides were proffered. Surprisingly, histology from the buttock plaque revealed a focally acanthotic dyskeratotic squamous epithelium with irregular buds, suggestive of a squamous cell carcinoma. The histology from one of the facial lesions confirmed a keratoacanthoma (KA). A unifying diagnosis of multiple KAs coexisting with KA centrifugum marginatum (KCM) was made. Treatment with low dose acitretin (10 mg/day) for 3 months resolved the KCM. The KAs decreased in number and size and have been less symptomatic. Multiple KAs may present in different forms; the commonest is the Ferguson Smith type where multiple self-resolving lesions occur in young adults, often of Scottish descent. Sporadic cases have also been reported. Our patient had multiple KAs with another rare keratoacanthoma variant, KCM. The response to acitretin concurs with previous experience, although higher doses have been used in the past. Precisely why retinoids are effective for KAs is unknown; it may modulate terminal differentiation of epidermal cells, thereby inducing inhibition of keratinisation. Alternatively, it could also have an antikeratin effect. The lack of family history, late age of onset, occurrence of two rare variants of KAs, and the response to low doses of acitretin makes our patient unusual. One cannot underestimate the role of the pathologist in helping the clinician make this rare dual diagnosis. Commercial support: None identified.
MARCH 2009