Desmoplastic Malignant Melanoma

A 68-year-old man sought dermatologic attention for a tumor of the arm. Biopsy specimen showed abnormal, essentially amelanotic, spindle-shaped cells in the cutis, greatly fibrotic stroma, and focal epidermal invasion. Desmoplastic malignant melanoma was diagnosed. The lesion was widely excised and axillary lymphadenectomy performed; one node showed metastasis. Nine months later, he died with widespread metastatic disease. To our knowledge, this is the first report of this entity since its delineation in 1971 and the only case in which diagnosis was established on initial biopsy and followed by definitive therapy. Desmoplastic melanoma has been confused with benign fibrosis, invasive fibromatosis, and fibrosarcoma, and is another example, with morpheaform basal cell carcinoma and sclerodermoid metastatic lesions from breast carcinoma, in which desmoplastic stroma may obscure the epithelial nature of cutaneous neoplasm.