Concomitant circumaortic and retro-aortic left renal veins associated with fenestrated renal artery.

Variations of the left renal vein can be in the form of circumaortic vein or renal collar, retro-aortic vein, additional renal vein, or multiple primary tributaries. We report a unique complex venous pattern of concomitant circumaortic and retro-aortic left renal veins associated with a fenestrated left renal artery. Two renal veins, anterior and posterior to the renal artery, originated from the renal hilum. The anterior vein was further divided into two branches. One branch passed through the fenestrated renal artery to continue as the anterior limb of the circumaortic vein. It received the suprarenal and gonadal veins and drained into the inferior vena cava. The other branch coursed posterior to the fenestrated renal artery and joined the posterior renal vein. The posterior renal vein was divided into two branches: one forming the posterior limb of the circumaortic vein, and the other continued obliquely downwards as the retro-aortic vein. Variations in the left renal vein have been implicated in several clinical conditions, such as varicocele and pelvic varices. It also plays a crucial role in renal transplantation, as the left kidney is often used as the donor organ. Even though many reports have been published on circumaortic and retro-aortic veins, the complex venous pattern associated with a fenestrated renal artery has not been reported previously.