[A Case of Anal Canal Adenocarcinoma with Perianal Pagetoid Spread without a Macroscopic Finding]

We report a case of anal canal cancer with Pagetoid spread without a macroscopic skin lesion. A 54-year-old man was admitted to a hospital with complaints of bloody stools. Endoscopic examination revealed a polyp in the anal canal, and endoscopic mucosal resection was performed. Pathological examination revealed an adenocarcinoma accompanied by Pagetoid spread and the positive surgical margin. We additionally performed trans-anal resection twice, but the resected horizontal margin was positive. Mapping biopsy of rectal mucosa and perianal skin revealed adenocarcinoma in only rectal mucosa. Abdominoperineal resection was performed. Histopathological examination showed invasive adenocarcinoma with pagetoid spread and that the surgical margin was negative. Pagetoid spread of anal canal adenocarcinoma usually showed macroscopic abnormal findings, but in this case, there was no skin lesion. It suggests that preoperative mapping biopsy is helpful for determining the excision range. It is necessary to keep in mind that anal canal adenocarcinoma with no skin lesion may cause Pagetoid spread.