an 80-year - old woman presented to the emergency department complaining that she had defecated a 40-cm corded piece of dark - red tissue , without severe symptoms , after taking laxatives . laboratory data revealed a white blood cell count of 7.8  10 and a hematocrit of 31.9% . the rest of the laboratory test results , including levels of serum albumin , hepatic and pancreatic enzymes , and electrolytes , were within normal limits . on physical examination , there was a slight tenderness in the lower abdomen without guarding or rebound on palpation . we observed approximately 20 cm of a necrotic bowel segment ( colon cast ) protruding from her anus ( fig . 1 ) . approximately 20 cm of a necrotic bowel segment ( colon cast ) protruding from the patient 's anus an emergency colonoscopy revealed that the sigmoid colonic mucosa located between 40 and 20 cm from the anal verge was edematous and congested . colonoscopy could not be performed past 40 cm from the anal verge because the patient complained of pain . the dark - red segment of tissue she passed before admission was considered a colon cast because the colonic mucosa of the corresponding segment was desquamated ( fig . the residual segment of the colon cast was still attached to the sigmoid colonic wall ( fig . 3 ) . colonoscopy finding of deciduous sigmoid colon epithelium with edema and congestion colonoscopic finding of residual colon cast ( arrows ) . histologic examination of the passed material indicated that the mucus layer had dissected from the colon , resulting in necrosis ( fig . computed tomography demonstrated thickening of the wall of the sigmoid colon , but no free intraperitoneal air , free fluid , fecal contamination , aortic aneurysm , or thrombi in superior or inferior mesenteric arteries were detected . histologic examination ( 12.5 , 100 ) revealed infarcted mucosa in the discharged colon cast . initially , oral intake was withheld for 10 days for maintaining the rest of the digestive tract in optimal condition for mucosal tissue healing ; subsequently , the patient successfully tolerated fluids and then food in 2 weeks . however , she began to present melena again when she started low - residue diets . colonoscopy revealed persistent inflammation in the sigmoid colon ; therefore , conservative treatment was continued for 2 months . two months later , a follow - up colonoscopy demonstrated mucosal regeneration and a stenotic lumen in the sigmoid colon ( fig . a water - soluble contrast enema revealed a slight stricture measuring approximately 4 cm in the sigmoid colon , although the patient was asymptomatic . the patient was discharged from the hospital 111 days after admission . at the 8-month follow - up , in 1984 , speakman and turnbull first reported spontaneous anal passage of a full - thickness infarcted colonic segment , also known as a colon cast . colon cast passage has been associated with a preceding circulatory disorder resulting in ischemic colitis . about 50% of these cases of colonic ischemia were secondary to blockage of the inferior mesenteric artery ( i m a ) in abdominal aortic aneurysm ( aaa ) repair surgeries and colorectal surgeries . five of the remaining cases had no relation with vessel obstruction secondary to operations , but with ischemic colitis from preceding circulatory disorders . in the 22 previously reported cases of colon cast , the colon segment often originated from the left side of the colon , including the descending colon , sigmoid colon , and rectum , with the exception of 3 cases in which the segment originated from the ascending colon . because of its peristaltic motion and vulnerability of the submucosal connecting tissue , the sigmoid colon appears to be a frequent site of colon cast development . peristaltic motion of the sigmoid colon mobilizes intestinal contents toward the rectum 1 or 2 times per day . the 22 cases , blockage of the feeding arteries , including the i m a , was the main cause . in 5 of the 12 cases , the etiology was occlusion of the i m a during aaa repair . in the 7 remaining cases , colonic ischemia was caused by sacrifice of the main blood vessel ( i m a in 5 cases ) during colon cancer surgery . in another 10 cases , the causes included diabetic ketoacidosis , pancreatitis , trauma , graft - versus - host disease , and ischemic colitis secondary to arteriosclerotic cardiovascular disease in patients receiving anticoagulant drugs . in the present case , the patient had arteriosclerosis , as can be inferred from her prescribed medications including aspirin for prophylaxis of angina pectoris . the continuous elevated pressure on the large bowel and decrease in blood flow as a result of atherosclerosis were likely the causes of ischemic colitis in this case . moreover , the elevated pressure on the large intestine and consequent vessel extension may have induced further circulatory compromise . the extended severe ischemic colitis was presumably the etiology of the colon cast in this case . data on the extent of infarction of the colonic wall were available in 19 of the reported cases . the extent of infarction from the mucosa to the muscularis propria or subserosal layer was reported in 13 cases . such cases required management with surgical resections because of colonic stenosis / obstruction or bowel perforation . however , 2 patients did not undergo surgery owing to their deteriorated status . in 6 patients , four of the 6 patients were successfully managed by conservative therapy with endoscopic dilation of strictures . two patients had strictures at the colorectal anastomosis site after colorectal surgery and required surgical resections . circulatory disorders affecting surgical manipulation may also cause stenosis of the colorectal anastomosis . despite the submucosal layer of the colon many cases are asymptomatic , so initial conservative treatment should be chosen together with regular examinations in cases without digestive tract perforation . when the specimen contains muscularis propria or the patients have colorectal anastomosis , we suggest following a surgical approach . we made a flowchart to describe the algorithm for the management of the cases with colon cast ( fig . we report a case of colon cast passage in a patient with severe ischemic colitis successfully treated by conservative therapy . the pathologic depth of the layer of the excreted colon cast may be crucial in determining the appropriate treatment . patients with casts consisting of the mucosa / submucosa layer alone and without colorectal anastomosis may likely be successfully managed by conservative therapy . when the specimens contain muscularis propria or the patients have colorectal anastomosis , surgery should be considered .