Epithelial-myoepithelial carcinoma: an immunocytochemical study.

An immunocytochemical study of epithelial-myoepithelial carcinoma, using antibodies to smooth muscle myosin, keratins, and type IV collagen, is presented. This rare tumor of salivary gland is composed of tubules and ductal structures, comprising an outer layer of clear cells that show myoepithelial differentiation and an inner layer of eosinophilic cells that show ductal differentiation. The findings in this study correlate well with previous ultrastructural descriptions of this tumor.