Arteriovenous fistula simulating a solid tumor of the kidney.

In this report we describe a 57-year-old male hemophiliac with an acquired renal arteriovenous (AV) fistula presenting as a renal mass. Even after intravenous pyelography, ultrasound and computed tomography, a carcinoma seemed possible. Causes, symptoms and therapy of renal AV fistulas are shown and pitfalls in the usual diagnostic approach are discussed.