A case of rectal carcinoma concomitant with Pagetoid lesion in the perianal region--histopathological and electron microscopic observations--.

A case of extramammary Paget's disease of the perianal area adjacent to a mucinous adenocarcinoma of the rectum is presented. The histopathological examination of the case revealed that within the epidermis adjacent to the invading rectal cancer nest, the formation of glandular structures can be observed occasionally, around which so-called Paget's cells are noted to be scattered and further many points of similarity between cancer cell and Paget's cell are proved by electron microscope. Perianal skin lesion looking like Paget's disease is proved to be due to intraepidermal spread of the rectal carcinoma. Referring to the literature, this is the first report to our knowledge, to elucidate the histogenesis of perianal extramammary Paget's disease associated with a rectal carcinoma using the electron microscopy.