Uncommon features of giant colonic diverticula.

Two patients with giant colonic diverticula were operated upon within one week. Uncommon features of this rare condition were observed in both patients: 1) the diverticulum was located outside the sigmoid colon, 2) smooth-muscle fibers and ganglion cells were present in the wall of the diverticulum, and 3) free perforation into the peritoneal cavity was the presenting symptom. Barium enema in one patient showed no communication between the diverticulum and the colonic lumen, despite evidence of such communication on histologic examination. Both patients were successfully treated by simple excision of the diverticulum without colonic resection.