Mechanism: A large, hard mass of impacted feces may interfere with the blood supply to the mucosa of the bowel, resulting in ulceration that dissects through the wall, resulting in bowel perforation.
Criteria for stercoral perforation of the colon:
(1) It typically occurs along the antimesenteric surface of the colon.
(2) It occurs in the left hemicolon, usually in the sigmoid or rectum.
(3) The perforation tends to be round or oval.
(4) The diameter of the perforation is typically > 1 cm.
(5) A stercoraceous mass is present in the colonic lumen at the site of perforation. It may protrude through the perforation.
(6) Histology of the lesion shows pressure necrosis or ulceration with a chronic inflammatory cell infiltrate around the perforation.
where:
• The blood supply to the colonic wall is poorest along the antimesenteric surface.
• The stool is driest and hardest in the distal colon due to water resorption.
• Stercoral simply means fecal.
