HIDROACANTHOMA-SIMPLEX - AN ULTRASTRUCTURAL AND IMMUNOHISTOCHEMICAL STUDY

A representative case of hidroacanthoma simplex was studied with routi ne light microscopy, immunohistochemistry, and electron microscopy. St aining with the periodic acid-Schiff reagent and immunostaining with a nti-keratin antibodies were useful in demarcating the tumor cells from adjacent normal epithelium. However, antibodies to carcinoembryonic a ntigen and epithelial membrane antigen did not help us to segregate or identify the neoplastic cells. Electron microscopy revealed tumor cel ls markedly different in appearance from luminal cells of the acrosyri ngium. Hidroacanthoma simplex does not appear to be derived from lumin al cells of the acrosyringium. We propose criteria for the histologic diagnosis of this benign neoplasm.