Aberrant renal hilar pelvic anatomy in a malrotated kidney.

Understanding variations in uretero-pelvic anatomy is of paramount importance from a surgical, radiological and academic perspective. We report an unheard renal hilar pelvic anatomy where the renal pelvis presented as the most anterior hilar structure. We believe an embryologic event in the renal ascent and rotation can account for this unusual presentation. Copyright:

INTRODUCTION

The arrangement of structures at renal hilum typically includes the renal hilum facing medially and the renal vein, artery, and pelvis arranged anteroposteriorly. Unlike this textbook description, cadaveric and clinical studies have reported variable patterns.[1] The variations in the branching pattern of renal vessels at the hilum are well reported. However, renal pelvis constituting the most anterior structure has never been reported to date. Kumar et al. further described and compared studies on renal hilar anatomy in cadaveric dissections.[2] The classical pattern of renal hilar structures from anterior to posterior as renal vein, renal artery, and renal pelvis was described in 20%–80% of patients. Renal artery, vein, and pelvis in that order were the next most frequent observation in anterior to posterior distribution.

CASE REPORT

We present the images of a healthy laparoscopic kidney donor with aberrant renal hilar anatomy. We performed a magnetic resonance imaging before kidney donation to ascertain renal hilar vascular anatomy. The left kidney had a normal size and vascular distribution. However, the pelvis of the left kidney was anatomically located anterior to the vein and artery [Figure 1]. The ureter further descended on the anterior surface of the kidney [Figure 2].

Figure 1

Left laparoscopic donor nephrectomy specimen. Arrows - Yellow: Ureter, Red: Renal artery, Blue: Renal vein

Figure 2

Magnetic resonance imaging image. Arrows - Yellow: Ureter, Red: Renal artery, Blue: Renal vein

DISCUSSION

Embryological changes or abnormalities in the normal ascent of the kidneys from a pelvic to lumbar position in adults can possibly account for most hilar structural variations.[3] Renal rotation usually occurs during its ascent and often precedes vascularization.[4] We believe that this rotational defect can reason the renal pelvis to present itself ventrally as was found in our case.

Understanding variations in uretero–pelvic anatomy is of paramount importance from a surgical, radiological, and academic perspective. Over the past few decades most urologic procedures including donor nephrectomies are being carried out using minimally invasive surgical techniques. Understanding the branching pattern of renal hilar vessels and their structural arrangement in relation to renal pelvis is a prerequisite to performing partial nephrectomies, endopyelotomies, and ureteric implantation during kidney transplant. Precise knowledge of normal and variant hilar anatomy can prevent operative complications.