Abstract

Obstructive colitis is an ulceroinflammatory lesion of the large intestine at a distance proximal to the obstructing or potentially obstructing lesion of any etiology. It has been suggested that a rise in the intraluminal pressure related to the obstruction results in a fall in the intramural blood flow with subsequent ischemic necrosis. We examined 7 cases of surgically resected obstructive colitis associated with distal constrictive adenocarcinoma of the large intestine. Two cases of the obstructive colitis were radiologically suspected prior to surgery either as a separate tumor mass or diverticulosis, and another case was suggested to be a tumor seeding by colonoscopy. Grossly, five cases presented with single or multiple, shallow, well-demarcated ulcerative lesions, and the remaining two were featured with a segmental ulcerative lesion the with pseudopolypoid area. The ulceroinflammatory lesions were separated from the distal obstructive carcinoma by a skipped zone of relatively normal mucosa measuring 4-43 cm. The proximal colon to the obstructive lesions were obviously dilated except in one case. Microscopically, mucosa and submucosa were replaced by granulation tissue, and showed inflammatory cell infiltration and fibrin exudates. Muscle coat often accompanied ischemic contraction. Fissuring was noted in one case. The recognition of these lesions prior to or during surgery is stressed based on the morphological features corresponding to an ischemic change in the proximal mucosa to the primary obstructive lesion.

• Keywords: Colon;Obstruction;Obstructive colitis;Pathology;