Unusual presentations of aorto-enteric fistula

Background: Aorto-enteric fistula is rare but can result in exsanguination without timely surgery or endovascular stent placement. Methods: Four cases of aorto-enteric fistula were reviewed in which the presentation was unusual and diagnosis difficult. Observations: The first patient had an aorto-sigmoid fistula in the setting of an aorto-bi-femoral graft. Two patients had a primary aorto-enteric fistula, one to the stomach from a suprarenal aortic aneurysm, and the other, to the duodenum in the setting of retroperitoneal spread of renal cancer. The aortoduodenal fistula recurred in the 4th patient within 3 months of surgical repair; this patient is the only one who survived long term. Conclusions: When presentation is atypical, the diagnosis of aorto-enteric fistula can be extremely difficult. Because investigative studies are not consistently useful in making a definitive pre-operative diagnosis, a strong index of clinical suspicion and a willingness to consider surgical exploration are essential for timely and successful management.