[Curative endoscopic submucosal dissection of laterally spreading sporadic tumor in ulcerative colitis:a case report].

A 60-year-old man visited our department because of watery diarrhea that lasted for several months. On colonoscopy, we diagnosed him as ulcerative colitis. Additionally, a laterally spreading tumor (non-granular type) was discovered in the rectum above the peritoneal reflection (Ra). The patient was initially treated with 5-aminosalicylic acid. Four months later, endoscopic submucosal dissection was performed. Histopathology examination showed a sporadic tubular adenoma. Complete en bloc resection was performed.