Pathologic Study on Ischemic Colitis and Obstructive Colitis

Abstract

Pathologic materials from nineteen patients with ischemic colitis were studied from a pathomorphologic viewpoint, and were compared with those from five patients with colitis occurring in the portion proximal to an obstructing carcinoma of the colon (obstructive colitis).
In the acute phase of both diseases there were diffuse mucosal hemorrhage and irregular open ulcers, Ul- I and/or Ul-II, having tendency to longitudinal situation and to association with pseudomembrane. The histologic features consisted of fresh mucosal hemorrhage, degeneration and necrosis of glandular epithelium, open ulcers, and marked submu-cosal thickening due to prominent edema, hemorrhage, congestion and neutrophilic infiltration. In the chronic phase, both disease presented the lesion made up of one and/or three, long, longitudinal, linear or zonal ulcers, open or healed, along the teniae coli. The microscopic appearances in the chronic phase consisted of five main pictures as follows: 1) ulcers of Ul-II, 2) open ulcers floored with vascular granulation tissue, 3) prominent fibro-musculosis and fibrosis in the submucosa adjacent to the healing ulcers, 4) presence of many hemosiderin-laden macrophages scattered throughout the whole thickness of the colon, 5) a slight inflammatory infiltrate consisting mainly of lymphocytes and plasma cells. In addition, slight to severe fibromuscular intimal thickening of the small to medium-sized arteries situated in the serosa is recognized in four cases of ischemic colitis and two cases of bstrucotive colitis, respectively.
Considering the pathomorphologic findings mentioned above, the both diseases may essentially be of identical nature and their causative factors resulting in the ischemic change of the colonic wall include arteriosclerotic changes, increased intraluminal pressure and spasm. In addition, the pathomorphogenesis of the characteristic ulcers in these conditions was briefly discussed.