Desmoplastic melanoma: clinicopathologic aspects of six cases

We report 6 cases of desmoplastic melanoma. Upon removal and histologic examination, each lesion consisted of a dermal nodule of fascicles of spindle cells, many of which showed pleomorphic and hyperchromatic nuclei. Fascicles, as well as single cells, were seen infiltrating the dermal collagen. Lentiginous hyperplasia of melanocytes with varying but usually slight cellular atypia overlay the dermal proliferations in all cases. Melanophages and some pigmented cells, albeit few in number, were present in the infiltrate, whereas mitotic figures were also noted. These features are most consistent with desmoplastic melanoma, a rare tumor of which a limited number of cases has been described. The clinical and histopathologic features of the lesions presented exemplify the diagnostic and therapeutic dilemma associated with desmoplastic melanoma.