Double anal canal cancers associated with a long history of perianal Paget's disease: report of a case.

Extramammary Paget's disease (EPD) is rare. We report a case of double anal canal cancers in a patient with a long history of perianal Paget's disease. The patient, a 68-year-old Japanese woman, refused surgery initially and was treated with electron beam therapy, which achieved remission. However, 6 years later, Paget's disease was found to be progressing again and double anal canal tumors were also detected in the proctos and external skin area. We performed abdominoperineal resection (Miles' operation) and lymph node dissection for the Paget's disease with double anal canal tumors. Immunohistochemical staining revealed cytokeratin (CK)-20 expression in the adenocarcinomas and Paget's disease lesion, but not CK-7 or gross cystic disease fluid protein-15 expression. The lesion was joined to the carcinoma by a stalk. The immunohistochemistry results suggested secondary EPD, although it was originally considered to be Paget's carcinoma (primary EPD) based on the clinical history.