Sigmoido-gluteal fistula--a rare complication in clinically asymptomatic chronic diverticulitis

Chronic colonic diverticulitis may be associated with typical complications such as local abscesses, stenosis, bleeding, intraperitoneal bowel perforations or fistulas to other organs. Most commonly, fistulas exist between the colon and the bladder; nevertheless, they may also extend to the small intestine, other areas of the colon, ureter, uterus, salpinx, vagina, abdominal wall, portal- and mesenterial venous system, pleura, urachus, biliary system and the hip. We report on a patient with chronic colonic diverticulitis having an unusual sigmoido-gluteal fistula along the sacrum, the piriformis muscle and sciatic nerve. The patient presented with sciatic nerve symptoms and recurrent gluteal abscess formation, but no other clinical symptoms leading to an abdominal pathology. Initially, that fact caused an unsuccessful local treatment under the differential diagnosis of a local gluteal abscess for about a year. Finally, a sigmoid colon resection with end-to-end anastomosis and a proximal diverting stoma was performed. The colostomy was closed electively five months later without any complication.