Rare communication between the aorta and the gastrointestinal tract.
Primary lesions occur most often in the presence of an atherosclerotic aortic aneurysm.
Also associated with infectious aortitis, enteric ulcers, tumor, trauma, radiation therapy, foreign body ingestion, and diverticulitis.
Secondary AE fistulas occur in prosthetic abdominal aortic vascular graft due to graft infection.