Early colon cancer presenting as intussusception and successfully treated using endoscopic submucosal dissection.

and successfully treated using endoscopic submucosal dissection Adult intussusception represents 5% of all cases of intussusception, and accounts for 1% of all cases of bowel obstruction [1]. Due to the significant risk of malignancy associated with this condition, with neoplasia found in approximately 65% of cases [2], intussusception in adults is treated by surgery, and in most cases cancer is discovered intraoperatively [3]. Thus, in most cases adult intussusception requires treatment by definitive surgical resection [2]. We report the first case of adult intussusception caused by early sigmoid colorectal cancer, which was successfully resected endoscopically. A 57-year-old man was admitted to our hospital with the complaints of lower abdominal pain and a tumor prolapsing through the anus. His white cell count was 8100/μL and his blood hemoglobin level 12.4g/dL. Abdominal computed tomography showed intestinal intussusception caused by the sigmoid tumor (●" Fig.1). The tumor was manually reduced into the rectum, relieving the patient of pain. The following day, sigmoidoscopy revealed a large subpedunculated polyp measuring about 50mm in diameter. Magnifying endoscopy with crystal violet staining (●" Fig.2) did not suggest that the tumor was associated with massive invasion of the submucosal layer, and endoscopic submucosal dissection (ESD) was performed. During this procedure, severe fibrosis and muscle retraction were observed in the submucosal layer (●" Fig.3); however, en bloc resection was successfully performed without anycomplications. The tumorwas 50×40mm in size; histological examination revealed intramucosal carcinoma, and that all the margins were tumor-free (●" Fig.4). Several reports have described an endoscopic treatment approach for intussusception associated with benign tumors [4,5]. However, there have been no reports of endoscopic resection carried out in cases of intussusception caused by early colorectal cancer. In our case, the physical findings, CT findings, and precise endoscopic diagnosis [6] after reduction of the prolapsing tumor led us to an accurate diagnosis, allowing this large tumor to be resected not by surgery, but by cautious ESD, which is a minimally invasive treatment [7].