Endoscopy is one of the valuable diagnostic methods for primary aorto-enteric fistula

The present report describes a case of primary aorto-enteric fistula (PAEF) in an 81-year-old man with no previous abdominal surgery. The patient was admitted to Teraoka Memorial Hospital in shock with repeated episodes of melena and hematemesis. We performed emergency endoscopy to establish a diagnosis and identified a ruptured aortic aneurysm visualized through a fistula in the second portion of the duodenum. As most PAEF cause massive gastrointestinal hemorrhage, prompt diagnosis is critical to ensure a successful outcome. Although the patient and his family refused surgery and the patient died, we were able to make the diagnosis at an early stage by endoscopy. While PAEF is usually very difficult to diagnose by a single modality, endoscopy can be one of the modalities to identify the source of gastrointestinal hemorrhages, even in cases of PAEF.