A rare cause of acute massive lower gastrointestinal bleeding.

Even if lower gastrointestinal bleeding (LGIB) can present as trivial haematochezia, massive hemorrhage with shock may occur. Acute massive LGIB is defined as bleeding of recent duration that originates beyond the ligament of Treitz and encompasses: passage of a large volume of red or maroon blood through the rectum, haemodynamic instability and shock, initial decrease in haematocrit level of 6 g/dL or less, transfusion of at least 2 U of packed red blood cells, bleeding that continues for 3 days or significant rebleeding in 1 week. This report presents the case of a 58-year-old man with massive LGI bleeding. Colonoscopy was performed in emergency with a poor colonic preparation, but the examiner fortunately and with difficulty managed to identify the source of the haemorrhage- a Dieulafoy's lesion of the right colon. The bleeding was successfully stopped permanently by injecting sclerosing agents into the spurting vessel. We have preferred colonoscopy as our first choice of investigation due to the facile availability and the opportunity of endoscopic haemostasis in case of finding the source of bleeding. Angiography was planned in case of failure of the first method. The definition, clinical presentation, and treatment of Dieulafoy's lesion are further discussed.