Retroperitoneal fibrosis presenting as colonic dysfunction: CT diagnosis.

In a patient who presented with pelvic pain and changed bowel habits, barium enema and sigmoidoscopic examinations demonstrated a nonspecific asymmetric narrowing of the colon at the rectosigmoid junction with normal mucosal appearance. Computed tomography revealed the etiology to be retroperitoneal fibrosis with pelvic extension and entrapment of the colon at this level. The importance of CT in diagnosis of this unusual manifestation of retroperitoneal fibrosis is discussed.