Abstract

Dermatofibrosarcoma Protuberans (DFSP) is a rare malignant fibroblastic dermal sarcoma with an estimated incidence of 4.2 per 1 million in the United States; the pigmented variant (Bednar tumor) accounts for 1-5% of total cases. The majority of DFSPs are identified on the trunk or proximal extremities; only rare case reports of pigmented DFSPs on distal extremities have been reported in the literature. The following case report is that of a 45 year old male who presented with subacute growth and new onset pain in a 13 year old mass on the dorsal aspect of his right third toe. A punch biopsy was performed and submitted for histopathologic evaluation. The specimen demonstrated a pigmented spindle cell lesion. Immunohistochemical analysis was performed on the specimen, which was strongly positive for CD34 and negative for HMB45. The lesion was favored to be a pigmented DFSP. Subsequent excision redemonstrated the same histologic appearance and staining properties. The purpose of this report is to relate the details of this unusual entity and presentation and encourage dermatopathologists to keep pigmented DFSP as a differential consideration in superficial fibroblastic neoplasms, regardless of site.

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