Recurrence of adenoma after curative endoscopic submucosal dissection for a rectal intramucosal adenocarcinoma in adenoma

Background and study aims A 71-year-old female underwent endoscopic submucosal dissection (ESD) for a subcircumferential lateral-spreading rectal tumor. Pathological examination showed an intramucosal adenocarcinoma in villous adenoma (size: 155 × 140 mm), which had been curatively resected with negative margins. However, follow-up colonoscopy revealed a tumor at the ulcer scar site, which soon grew into a circumferential lesion. Nineteen months after the first ESD procedure, additional ESD was performed for the recurrent lesion, which was resected en bloc without any adverse events, although severe fibrosis was noted in the submucosa. Pathological examination revealed a villous adenoma similar to the primary lesion with negative margins, but tumor cell nests were also present in the submucosa, which implied that tumor cell implantation had occurred during the first ESD. The post-ESD ulcer bed was subjected to argon plasma coagulation to prevent tumor recurrence after confirmation of the pathological results. There have not been any signs of recurrence during 9 years of follow-up.