Sarcomatoid carcinoma of the skin: report of a case.

We report the histological, immunohistochemical and ultrastructural findings of an exophytic cutaneous tumor composed of a mixture of typical basal cell carcinoma (BCC) and malignant fibrous histiocytoma. Nine previously reported carcinosarcomas of the skin are reviewed. We prefer the term "sarcomatoid carcinoma" for this rare neoplasm. Only the BCC showed a positive immunoreaction to cytokeratin; the sarcomatous component was negative, but it did express vimentin, and, focally, smooth-muscle-specific actin and KP1 (CD68). Both components showed p53 immunostaining.