SPINDLE CELL EPITHELIOMA, THE SO-CALLED MIXED TUMOR OF THE VAGINA - ACLINICOPATHOLOGICAL, IMMUNOHISTOCHEMICAL, AND ULTRASTRUCTURAL ANALYSIS OF 28 CASES

A total of 28 examples of vaginal mixed tumors, a circumscribed tumor composed predominantly of spindle cells, but often admixed with minor glandular, and focal areas of squamous differentiation along with loca lized hyaline globules, were evaluated. In addition to the clinicopath ologic correlation with light microscopy, 10 cases were analyzed immun ohistochemically by a panel of antibodies for keratin, smooth muscle a ctin, S-100 protein, and glial fibrillary acidic protein; five cases w ere also evaluated for estrogen and progesterone receptors. Ultrastruc tural analysis was performed on two tumors. The results indicate an ep ithelial differentiation in the predominating spindle cells based upon an intense immunoreaction with cytokeratin in nine of 10 cases and th e presence of tonofilaments and desmosomes at the ultrastructural leve l. Contrary to mixed tumors of salivary gland and breast origin, no ev idence of a myoepithelial differentiation was identified in these tumo rs. The name vaginal spindle cell epithelioma is proposed for these ne oplasms as being more descriptive of the true nature of these tumors.