Solution: Stercoral colitis is an inflammatory process in the colon related to fecal impaction, leading to ischemic pressure necrosis and ultimately colonic perforation. If you see fecal impaction, focal colonic wall thickening and adjacent fat stranding, you should think of stercoral colitis. In this case, it has gone on to ulceration and perforation. The retroperitoneal air is obvious. On image 5, you can see the focal defect in the left lateral colonic wall. This is a relatively rare condition, but should be one that you are aware of. By the way, the wall thickening and fat standing can be fairly subtle, but remember, if you have a very dilated colon due to fecal impaction, the colonic wall should be paper thin due to the distention.