On the nature of desmoplastic melanoma.

Pathologic study demonstrated lentigo maligna melanoma in three of four cases of desmoplastic melanoma and demonstrated spindle cell masses with features of atypical fibroxanthoma in all four of the cases. Pigment enzymes of melanosomes were not found in the mesenchymal portion of the tumor. The cellular atypia and the histochemical and ultrastructural findings favor the fibroblastic nature of this melanoma-related dermal mass.