Massive fecal impaction presenting with megarectum and perforation of a stercoral ulcer at the rectosigmoid junction.

A 25-year-old male with lifelong constipation presented to the emergency department with an acute abdomen. Initial resuscitation was performed, and the patient underwent urgent laparotomy. He was found to have feculent peritonitis with megabowel involving the rectum and sigmoid colon and a stercoral ulcer with full thickness erosion, and perforation was also identified on the anti-mesocolic surface at the rectosigmoid junction. Abdominal irrigation and subtotal colectomy with proximal fecal diversion was performed. This case illustrates that recognition of severe, chronic constipation should lead to interventions including disimpaction and aggressive medical management. When indicated, megabowel can be managed surgically in an elective setting based on anatomic findings and physiologic studies. Peritonitis is an ominous late finding in patients with severe constipation.