Objective: It is not common that, after diversion of the faecal stream by a colostomy, the defunctioned colon develops colitis. The pathogenesis of this colitis is still unclear and it has been proposed that ischaemia may play a major role. Our aim is to look for signs of ischaemia in a group of patients developing colitis after diversion colostomy for various causes.
Method: Surgical specimens from 32 patients resected for colitis developed after diverting colostomy were examined with routine (haematoxylin-eosin) and Elastic-Van Gieson and Perls' stains.
Results: The histological features related to mucosal crypt architecture, crypt epithelium and inflammation were mild, non specific or related to the underlying disease. Fibrosis was present in 21 (65.6%) patients, superficial coagulative necrosis was found in 18 (56%) patients, splitting and/or thickening of muscularis mucosae was present in 20 (62%) patients. The vessels were substantially normal or ectasic without thrombi or alterations in the wall. Evident ischaemia with coagulative necrosis, submucosal oedema and focal fibrosis was detected in only two (6%) patients and an intermediate picture between acute and chronic ischaemia was present in 16 (50%) patients.
Conclusion: It is possible that ischaemia plays some role in the pathogenesis of diversion colitis; however, further studies are needed to firmly establish its role.