Stercoral perforation is defined as a bowel perforation due to pressure necrosis from a fecal mass (fecaloma). It is an uncommon, but life-threatening, complication of unresolved fecal impaction and can be a cause of acute abdomen secondary to fecal peritonitis.
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Epidemiology
It may represent 3.2% of all colonic perforations and 2.2% of randomly-selected autopsy examinations 2. It generally occurs in older individuals 8.
Associations
Conditions causing chronic constipation, see article on fecaloma for list of associations and etiologies.
Pathology
The postulated pathogenesis is from a rise in intraluminal pressure which becomes greater than the capillary perfusion pressure within the bowel. This then results in focal ischemia, necrosis, ulceration, and ultimately perforation 1,2.
Location
It typically involves the rectosigmoid colon on the antimesenteric side in ~90% of cases 7.
Radiographic features
CT
A universal component in a stercoral perforation is the formation of a fecaloma which is a localized hard, inspissated, or calcified fecal mass, usually of a diameter equal to or greater than the colonic lumen (due to the lowest blood supply and narrowest diameter).
Hyperdense mucosa may be seen on non-contrast CT scans.
There is evidence of extraluminal gas +/- extruding fecal content. The site of perforation usually involves the antimesenteric border of the colon.
Treatment and prognosis
They can be life-threatening with mortality rates ranging between 30-55% 8.
Stercoral perforations are almost always free and open, although to some extent plugged by a fecaloma, hence unlikely to resolve spontaneously with conservative management.