Pathology report:

A total colectomy has been performed.

Sections show large bowel with confluent coagulative necrosis of mucosa, associated with hemorrhage and a relatively sparse acute inflammatory infiltrate. There is occasional preservation of crypt bases and muscularis propria. The submucosa is edematous and hemorrhagic. Occasionally there is transmural acute inflammatory infiltrate associated with patchy necrosis of muscularis propria. At the margins the mucosa is necrotic however the muscularis propria appears viable. The mesenteric vessels contain blood however thrombosis is not seen and there is no evidence of vasculitis.

DIAGNOSIS: Large bowel: Acute ischemic colitis with early infarction.

This case was not prospectively called ischemic colitis, but the patient went to theater since she was clinically peritonitic.

TEACHING POINT: apart from obstructing lesions resulting in colonic distension, consider a vascular insult.