Large external iliac vein aneurysm in a patient with a post-traumatic femoral arteriovenous fistula.

We report about a young patient with a large aneurysm of the left external iliac vein associated with a traumatic arteriovenous fistula between the left superficial femoral artery and the femoral vein after a stab wound 20 years ago. The patient presented with swelling of the left leg, which developed during the past years and worsened after saphenectomy 12 months before hospital admission. The chronically hyperperfused common iliac artery proximal to the arteriovenous fistula was compressing the common iliac vein. The venous outflow obstruction and subsequent venous hypertension render a possible explanation for the formation of the iliac vein aneurysm. Surgical repair of the venous aneurysm by interposition grafting and closure of the arteriovenous fistula was successful. A postoperative computed tomography scan showed a 50% size reduction of the feeding artery, underlining the ability of the arterial system to normalize arterial diameter in response to flow reduction, even after a high flow situation had existed for probably >20 years.