[Inverted sigmoid diverticulum simulating polyps].

The authors write about the inversion, a rare complication of the diverticulum of the sigmoid colon. The colour, surface of the diverticulum, 15 and 8 mm in diameters, were the same as the colon mucosa, it was soft and mobile by tacting. Biopsy was performed which caused a serious complication, a perforation to the free abdominal space, requiring a surgical operation. The inverted diverticulum can be distinguished from a polyp not by endoscopy, but by double contrast barium enema. Detecting a long, soft, mobile mass in the colon, must be thought about an inverted diverticulum and the biopsy must be omitted.