Hidroacanthoma Simplex with Porocarcinomain situの2例

Two cases of hidroacanthoma simplex with porocarcinoma in situ are reported. The first case was an 80-year-old woman with a tumor on the right back and the other was an 85-year-old woman with a tumor on the right side of her abdomen. On histological examination, both tumors showed intraepidermal epithlioma. These tumor cells had atypical nuclei and a fairly abundant, pale-stained cytoplasm. Some of them had periodic acid-Schiff positive, diastase-digestive granules and alcian blue at pH 2.5 positive substances. Immunohistochemical studies revealed positive reaction for carcinoembryonic antigen and epithelial membrane antigen in both tumor cells.