Retroaortic Left Renal Vein: A Case Series and Clinical Significance in Renal Surgery.

The retroaortic left renal vein (RLRV) is a rare anatomical variant in which the left renal vein passes posterior to the aorta. Although often asymptomatic, awareness of this anomaly is essential for avoiding vascular injury during retroperitoneal or renal surgery. We report three incidental cases of RLRV identified during imaging studies performed for unrelated renal or urinary conditions. A 53-year-old man presented with colicky left flank pain and multiple left renal calculi on computed tomography (CT). An incidental type I RLRV with orthotopic drainage into the inferior vena cava (IVC) at the L1-L2 level was detected. He opted for conservative management with elective laser lithotripsy planned. An 86-year-old woman presented with fever and bilateral flank pain due to urinary tract infection and left ureteric obstruction. Contrast-enhanced CT demonstrated bilateral pyelonephritis, left hydronephrosis, and a type II RLRV draining at the level of L4. She underwent ureteral stenting and intravenous antibiotics, with complete recovery. A 67-year-old woman presented with right flank pain due to a distal ureteric calculus. Non-contrast CT revealed a type III RLRV encircling the aorta. She was treated with double J stenting and conservative management, with spontaneous stone expulsion after one month. All patients were managed for their primary conditions, and the venous anomaly required no intervention. Although frequently incidental, RLRV has important surgical implications. Preoperative identification through contrast-enhanced imaging allows appropriate surgical planning and prevention of intraoperative vascular complications.