胸部に生じたＥｃｃｒｉｎｅ Ｐｏｒｏｃａｒｃｉｎｏｍａの１例

Abstract

We report a case of a 53-year-old woman who first noticed a skin tumor on her right chest between 4 and 5 years earlier. The size increased gradually, and at the initial consultation in our hospital, she had a dark brown to black coloured tumor measuring 15×20mm on her right chest. On biopsy, histological examination revealed the nests of poroma cells scattered in the epidermis and she was diagnosed with hidroacanthoma simplex.After 3 years, she consulted our hospital again. Tumor had grown to 18×24mm size and scales adhered to its surface. The tumor was totally excised and examined histologically, immunohistologically, and by electron microscopy.Histologically, PAS-positive tumor nests proliferated in the dermis. Atypical tumor cells demonstrated clear nuclei, and mitosis or dyskeratosis were found. Canaliculi were also found in the tumor nests. Immunohistologically, CEA, EMA, and keratin were positive, but S-100 protein was negative in the tumor nests. Electron microscopy examination revealed that intracellular canaliculi existed in tumor cells which had abundant microvilli on their surface.From these findings, we suppose that hidroacanthoma simplex developed into eccrine porocarcinoma over several years.