Bipolar supernumerary renal artery.

The variations of renal arteries are considered critical issues that surgeons should have thorough envision and appreciation of the condition. Variations of these vessels may influences urological, renal transplantation and laparoscopic surgeries. We present a case of bilateral accessory renal artery with a striking pre-hilar branching pattern encountered upon digital subtraction angiography (DSA) for imaging of the renal arteries of a healthy 30-year-old man, renal transplant donor. The right kidney received two renal arteries from the aorta including a main hilar and one lower polar. However, the left accessory artery while originated from the aorta, simultaneously, supplied both upper and lower renal poles following its pre-hilar division that replaced upper/apical and lower segmental arteries of the single main renal artery, respectively. The left main renal artery divided into two anterior and posterior segmental arteries. Whether this should be categorized either as an accessory hilar artery or a unique variant of renal arterial supply, the so-called bipolar supernumerary renal artery, is a matter of debate. We discuss possible embryologic origin and clinical aspects of accessory renal artery.