RESUMO
Aortoenteric fistulas (AEFs) are a rare and deadly cause of gastrointestinal bleeding that can be easily overlooked, leading to massive bleeding. Secondary AEFs are more common than primary AEFs. An example of a secondary cause of anemia is postoperative hemorrhage due to a surgically placed aortic graft or after endovascular aneurysm repair. This report aims to increase the awareness of AEF as a differential diagnosis when anemia is detected. The clinical report presents a case of anemia in a 79-year-old man due to a secondary AEF, which occurred in a patient who had undergone abdominal aortic aneurysm surgery 10 years before. Surgical repair is considered the gold standard for AEF treatment; however, in this case, the patient was managed with medical therapy and discharged after two months.