Desmoplastic neurotropic melanoma.

Desmoplastic neurotropic melanoma (DNM) is a rare variant of a spindle cell melanoma. The majority of these tumors occur on the head and neck of elderly patients. The rather variable clinical appearance (e.g. frequent lack of pigmentation) makes initial diagnosis often difficult. Histologically, DNM may show a lentiginous melanocytic proliferation with atypia and pleomorphic spindle cells in the dermis. Immunostaining for S-100 is usually positive although staining for HMB-45 is frequently absent. As with other melanomas, surgery is the first line treatment for DNM. Unlike other melanomas, however, survival for DNM may be better compared with other forms of melanoma.