Intussusception of rectosigmoid colon cancer mimicking a pedunculated tumor.

Intussusception in adults is a rare phenomenon involving the colon in approximately 20% of cases. A 65-year-old man was hospitalized with anorexia, anemia, dehydration, and melena. Digital rectal examination revealed a palpable mass approximately 5 cm from the anal verge. The mass moved between the rectosigmoid colon and the rectum below the peritoneal reflection during radiographic examinations and during sigmoidoscopy. We strongly suspected a rectosigmoid pedunculated tumor and performed a low anterior resection. Intraoperatively we observed intussusception of the rectosigmoid colon with easy manual reduction. The tumor was palpable in the rectosigmoid colon. The postoperative course was uneventful. This case illustrates intussusception of a rectosigmoid type 1 colon adenocarcinoma mimicking a pedunculated tumor.