Passage of a sigmoid colon cast in a patient with ischemic colitis.

Colon cast passage, which is the spontaneous passage of a full-thickness, infarcted colonic segment per rectum, is a rare occurrence. The main cause is acute ischemic colitis resulting from a circulation compromise. Most of the colon cast cases reported were secondary to abdominal aortic aneurysm repairs or colorectal surgery. We report a case of an 80-year-old woman with ischemic colitis who excreted a 20-cm colon cast. In most cases that involve a colon cast containing a muscle layer component, invasive therapy is required owing to colonic obstruction or stenosis. However, in the present case, the colon cast consisted only of a mucosa layer and was not associated with severe stenosis or obstruction; therefore, it was successfully treated by conservative therapy. Histologic examination of the colon segment may be crucial in determining the appropriate treatment.