Colonic Obstruction Due To Localized Giant Pseudopolyposis Complicating Ulcerative Colitis

Abstract

Localized giant pseudopolyposis is an interesting but extremely rare feature of pseudopolyposis complicating ulcerative colitis or Crohn's disease. The lesion represents a localized exuberant collection of pseudopolyps giving rise to a large discrete intraluminal colonic mass, which may simulate neoplasms such as villous adenoma or polypoid cancer. Our case concerns a 50 year old man, with a 10 year history of pancolonic ulcerative colitis under medical treatment, who presented with symptoms of subacute large bowel obstruction. At colonoscopy a large polypoid lesion was found in the distal transverse colon, causing almost complete luminal obstruction. In abdominal CT scan an obstructive thickening of the distal transverse colon, just before the splenic flexure, was seen, with the question of malignancy. The patient went on surgery and a total colectomy with ileorectal anastomosis was performed. The giant polypoid mass was located in the distal transverse colon and extended circumferentially in a distance of 15cm, causing almost complete luminal obstruction. Its macroscopic features were highly suspicious of malignancy. The microscopic examination revealed multiple pseudopolyps on a background of active ulcerative colitis changes, confirming the diagnosis of localized giant pseudopolyposis. The patient's postoperative recovery was uneventful.