18 - A Unique Combination of an Ectopic Left Kidney with Extrarenal Calyces, Multiple Renal Arteries, Circumaortic Venous Drainage, and an Inferior Polar Renal Vein

Poster Board Number: 18
There are separate poster presentation times for odd and even posters.
Odd poster #s – first hour
Even poster #s – second hour

Abstract Body : INTRODUCTION - Variation in renal arterial supply is common in the general population. However, variations in the renal collecting system and/or renal drainage system are rarer occurrences that are often associated with positional abnormalities of the kidney. Much of the literature regarding these variations attempts to determine potential embryological causes for the differences in anatomy while discussing potential clinical implications associated with atypical anatomy.

CASE DESCRIPTION - During routine dissection of the retroperitoneal region for a graduate level gross anatomy course, multiple variations in renal morphology were observed in a 78-year-old female cadaver. Immediately upon dissection and removal of the perirenal fat of the left kidney it was observed that components of the collecting system and renal venous system were emerging from the renal hilum on the anterior surface of the kidney rather than typically from the medial border. The left kidney was located more inferiorly than the right kidney, indicating that it had not fully ascended during development.

Collecting System Variations: Further dissection of the collecting system revealed three distinct renal calyces outside the renal tissue draining into an anteriorly placed renal pelvis. These extrarenal calyces were named superior, inferior, and lateral, based on their position on the anterior surface of the kidney.

Venous Variations: Two anteriorly placed veins were observed emerging adjacent to the collecting system structures. These two veins joined together to form the left renal vein which connected to the inferior vena cava. From the point where the two anteriorly placed veins join there was another venous structure that traveled posterior to the aorta before joining with the inferior vena cava creating a circumaortic venous collar. An additional vein, the inferior polar vein, was observed draining the inferior pole of the kidney directly to the left common iliac vein.

Arterial Variations: The arterial supply to the left kidney was observed to arise from three sources rather than a typical single renal artery. The most superior vessel, the superior polar artery, was a direct branch from the aorta to the posterior surface of the superior pole of the kidney. The second arterial structure supplying the kidney, the main renal artery, branched from the aorta 6.96cm below the superior polar artery. Before entering the renal tissue, it divided into anterior and posterior divisions. The anterior division branched into anterior superior and anterior inferior segmental arteries while the posterior division traveled on the posterior surface of the kidney until its termination into the renal tissue near the lateral border of the kidney. The third artery, the inferior polar artery, originated from the left common iliac artery and traveled with the inferior polar vein to the inferior pole of the kidney.

SIGNIFICANCE and CONCLUSION - This case presents an unusual combination of variations that had previously been unreported together. Knowledge of these variations are significant for surgeons as well as radiologists. Though these variations in renal structure are not typically associated with altered renal function, they can help give insight into embryological development of the urogenital system.