Recurrent intussusception of the sigmoid colon caused by a transanal protruding sessile tubulo-villous malignant polyp.

We report a case of a 35 year-old woman with a large malignant sessile tubulo-villous polyp of the proximal end of a dolico-sigmoid colon causing intussusception and transanal prolapsing. The diagnosis presented some difficulties being the intussusception intermittent. The clinical feature had been initially misdiagnosed for a very large bleeding polyp (5 cm in size), protruding out of the anus with a long pedicle in the rectum. The histology of multiple bioptic samples of the lesion revealed malignancy. Conventional radiologic studies (plain x-rays, barium enema) after metal clips had been placed on the head of the polyp before it rose up the colon, led to the correct diagnosis without, nevertheless, documenting intussusception. An elective surgical resection of the dolico-sigmoid colon allowed the correct diagnosis and the curative treatment of the colonic intussusception and the malignancy.