Circumaortic left renal vein: a cadaveric case study

Abstract Circumaortic left renal vein (CLRV) is a rare variation in which two renal veins encircle the aorta prior to draining into the inferior vena cava (IVC) and can be classified into three types based on branching pattern from the renal hilum. This case study aims to describe a rare case of a type III circumaortic left renal vein identified during routine dissection of a donor cadaver, and to discuss the gross anatomical characteristics, embryological origin, and clinical significance of this variation. Following dissection, images and measurements were documented, and a schematic representation of the CLRV was illustrated using procreate software. Based on the classification system proposed by Nastis et al., the CLRV was classified as type III, as it forms an anastomosis between the preaortic and retroaortic veins prior to draining into the IVC. Unique tributaries were noted, including two accessory suprarenal veins draining into the retroaortic vein. This variation has the potential to cause significant complications in the surgical setting, specifically in retroperitoneal abdominal surgery, nephrectomy, and laparoscopic procedures, emphasizing the importance of pre- or intraoperative identification. Although rare, CLRV has the potential to cause clinical symptoms as a result of increased venous pressure due to compression of the retroaortic renal vein between the aorta and vertebral column. This case of a rare type III circumaortic left renal vein with unique tributaries including multiple accessory suprarenal veins highlights the need for awareness and documentation of vascular variants to prevent potential clinical or surgical complications.