What are the features of a circumaortic left renal vein? How common is this anatomic variant?
A circumaortic left renal vein is an anatomic variant in which the left renal vein forms a ring around the abdominal aorta. It has a prevalence of 1.5% to 8.7%. The anterior segment of the ring connects with the IVC at the expected level of the left renal vein, and the posterior segment connects with the IVC below the level of insertion of the anterior segment.