Summary

A 69-year-old man presented to the emergency department with sudden onset abdominal pain. He was hypotensive and tachycardic with a peritonitic abdomen. On admission, the patient had been taking clopidogrel, a known cause of spontaneous retroperitoneal haematoma. An initial computed tomography of the abdomen showed a mass in the pelvis, which was thought to most likely be a gastrointestinal stromal tumour arising from the sigmoid colon. Explorative surgery identified a retroperitoneal haematoma of the rectosigmoid region. There was no evidence of bowel perforation. Hence a washout and closure was performed. Five days following an initial improvement, the patient developed symptoms of peritonitis. A second operation revealed that the rectum had become necrotic and perforated with free faeces. The ischaemia was caused by the retroperitoneal haematoma restricting the blood supply to this part of the upper rectum.