Myoepithelioma of the parotid gland. Report of two cases with immunohistochemical technique for S-100 protein and electron microscopic observation.

Two cases of myoepithelioma occurring in the parotid gland were reported. These tumors consisted of spindle cells that exhibited an arrangement similar to leiomyoma or fibroma. The diagnosis was made on the basis of characteristic ultrastructural as well as immunohistochemical findings: The tumor cells of the two cases likewise contained myofilaments and gave a positive result for the S-100 protein immunohistochemical technique.