Polypoid endometrioma of the rectosigmoid.

Endometriosis of the bowel most often involves the sigmoid and rectosigmoid and appears as an intramural mass protruding into the lumen in a polypoid or constricting fashion. Occasionally there is an intraluminal mass without obvious intramural involvement. Endometriosis of bowel is rarely diagnosed at endoscopic biopsy. We present a patient with an intraluminal endometrioma with a positive endoscopic biopsy.