Passage of "colonic cast" after colorectal surgery: report of four cases and review of the literature.

Anal passage of a full-thickness infarcted colonic segment (so-called "cast") not accompanied by any features of acute peritonitis is a very rare occurrence and may be the main advertising manifestation of acute colonic ischemia. Most of the reported cases of acute colonic ischemia are secondary to abdominal aortic aneurysms and ensuing inferior mesenteric artery thrombosis or to the repair of these aneurysms. The preceding events causing ischemia in other cases are Hartmann reversal, rectal resection and colonic J-pouch construction, and acute pancreatitis. In this article we present our experience on four cases of colonic cast passage, all of which developed subsequent to colorectal resection. Three of these casts are supposed to be mucosal and one is transmural. Generally, surgery is the rule and consists of the resection of the concerned ischemic segment. Every clinician should be aware of this form of presentation of bowel ischemia, not only following aneurysm surgery but also in the postoperative course of colorectal surgery.