A Case of Non-tumor Forming and Anal Gland Originating Anal Canal Cancer with Pagetoid Spread

Abstract

An 81-year-old man presenting with unpleasant sensation of the anus was referred to our hospital with a diagnosis of perianal Paget's disease. Neither recognizable tumor nor ulcer formation was proved in the anal canal and the rectum, but a biopsy with immunological staining resulted in CK20 positive and GCPFD15 negative. We diagnosed the case as pagetoid spread of anorectal cancer and performed abdominoperineal resection. Histopathology confirmed tumor cells to be within the anal gland, and furthermore signet ring cell carcinoma to have progressed from the anal canal epithelium to the surrounding skin. Accordingly, pagetoid spread of anal gland originating anal canal cancer was diagnosed. This case is extremely rare wherein anal gland originating intraepithelial cancer of the anal canal, which did not form any demonstrable tumor in the anal canal, displayed pagetoid spread. We present the case with some bibliographical comments.