[A Case of FAP Who Underwent Mucosectomy for Intramucosal Cancer That Repeatedly Developed in the Residual Rectal Mucosa after Stapled Ileal-Pouch Anal Anastomosis].

When we perform stapled ileal pouch anal anastomosis (IPAA) for familial adenomatous polyposis (FAP), some rectal mucosa persists. There is no consensus on surgical treatment when cancer develops at the residual mucosa. We report the case of a 43-year-old woman who repeatedly underwent endoscopic resection for intramucosal cancer that developed in the residual rectal mucosa 6 years after stapled IPAA, which she received at age 33. She was referred to our department for surgical treatment. We performed mucosectomy for the residual rectum mucosa, including a 0-Ⅱa lesion at the anterior wall. Two months later, stenosis was observed at the anastomotic site. We repeatedly conducted balloon expansion of the stenotic lesion. Six months later, the resected lesion was covered with white epithelium, and columnar epithelium was confirmed by step biopsy of the epithelium from the dentate line to the ileoanal pouch anastomotic site. This finding indicated that the regenerating epithelium was derived from the epithelium from the anal side. The patient remains well after 2 year 4 months with no complaints.