ABSTRACT
A primary aortoenteric fistula is defined as the spontaneous development of communication between the gastrointestinal tract and the native aorta. This is unlike a secondary aortoenteric fistula that occurs after surgery, such as a vascular graft. A primary aortoenteric fistula is an extremely rare cause of upper gastrointestinal bleeding. The condition is often overlooked because of its extremely low incidence. This paper reports a case of a 75-year-old man who presented with massive melena. Esophagogastroduodenoscopy revealed an ulcer measuring approximately 1.3 cm with a huge pulsating vessel in the third portion of the duodenum. Later, the diagnosis of primary aortoduodenal fistula was confirmed. The patient died in the preoperative stage due to massive bleeding. The findings of this case suggest that the endoscopists should recognize aortoenteric fistula as a potential cause of gastrointestinal bleeding.