We report a 60-year-old woman with intramucosal adenocarcinoma arising in the interposed colon, 40 years after the esophageal reconstruction for lye induced esophageal stricture. Although synchronous adenomas were also found in the native colon where the graft was taken, the number of adenomas was greater in the interposed colon and more dysplastic, even progressed to adenocarcinoma, than that of the native colon. The microsatellite instability-testing performed in the intramucosal carcinoma from interposed colon showed absence of microsatellite instability. Changing of location and functional demand of colonic segment, and the exposure to different intraluminal contents might have facilitated the adenoma- carcinoma transformation in the interposed colon.