Epithelial-myoepithelial carcinoma of the salivary glands: a clinico-pathologic, immunohistochemical and DNA flow cytometric study of three cases.

Epithelial-myoepithelial carcinoma is a rare neoplasia of the salivary glands. Histologic, immunohistochemical and flow cytometry analysis were used to study three new cases involving the major salivary glands of two women and one man. The mean age was 66.7 years. Immunohistochemistry confirmed the epithelial-myoepithelial dualism of the tumors: the predominant growth pattern showed ducts made up of an external myoepithelial layer and an internal epithelial layer. Proliferative activity, assessed by means of the PCNA and Ki-67 immunostaining and the study of the S-phase with flow cytometric analysis, proved to be higher in a recurrent case. All three cases were diploid. The use of immunohistochemical and flow cytometric techniques for the assessment of proliferative activity would seem to be an efficient method for the selection of a subgroup of epithelial-myoepithelial carcinomas with unfavorable prognosis.