Histologically, the colonic mucosa was largely ulcerated and necrotic (Images 03 and 04). The normal mucosa was replaced by pseudomembranous plaques of fibrin, cellular debris, and neutrophils (Images 05 and 06). In some areas, relatively normal mucosa with preserved glandular architecture was seen adjacent to mushroom-shaped necrotic plaques (Image 07). In some patients, perforation of the muscularis allows pathogens and inflammatory cells to enter the abdominal cavity resulting in peritonitis and/or sepsis (Image 08).
The patient's stool was positive for Clostridium difficile toxin.