Rhabdomyosarcomatous (myoblastic?) phenotype of metastatic malignant melanoma. A case report.

Melanoma may present a great variety of cell morphology and mimic virtually almost all other neoplasms, and metastatic lesions pose major diagnostic difficulties. A typical immunoreactive profile of melanoma is: S-100p- and HMB-45-positivity, but these markers are not always present. Other new antigens for melanoma are NKIC3 and Anti-Melan-A (MART-1). This tumor may also present expression of unspecific markers, as cytokeratin, CEA, EMA, desmin, NFP, GFAP, CD68 and actins. We present here unusual features of two metastatic melanomas, showing the anaplastic pattern, immunopositive for desmin.