Left retrocaval ureter without situs inversus or inferior venacava duplication.

Retrocaval ureter (pre-ureteral vena cava) is an uncommon congenital anomaly that causes ureteral obstruction by external compression. Although right retrocaval ureter is a common entity, left retrocaval ureter is extremely rare. A left retrocaval ureter is usually associated with situs inversus or duplicated inferior venacava (IVC). An isolated left retrocaval ureter with single left-sided IVC is even rarer and only four cases have been reported in the literature. We present images of a case with isolated left retrocaval ureter with a single left-sided IVC without situs inversus.

INTRODUCTION

A retrocaval ureter or pre-ureteric venacava is a rare anomaly which occurs in 1 per 1000 live births. This is caused by an abnormal development of Inferior Venacava (IVC). It is seen three times more often in males and is usually on the right side. A left retrocaval ureter as such is very rare and is usually associated with situs inversus or IVC duplication[12345]. Isolated left retrocaval ureter without any situs or IVC duplication is very rare. These patients usually present in the third or fourth decades and symptoms depend on the degree of obstruction.

CASE REPORT

An 84-year-old male patient presented to us with dull, aching left flank pain of 6 months duration. He was moderately built, well-nourished and ambulant with no physical abnormalities. Ultrasonogram of the abdomen revelaed left hydroureteronephrosis. X-ray of kidney, ureter, and bladder was non-contributory. CT scan of the abdomen revealed transposed IVC to the left side and classic retrocaval ureter with proximal hydro-ureteronephrosis [Figures 1–3]. All other viscera were orthotopically placed. Chest X-ray showed normally placed cardiac shadow.

Figure 1

Intravenous urogram showing a sea-horse sign

Figure 3

Axial CT images with arrows showing (a) Pre-caval Ureter (b) Post-caval ureter and (c) Left renal vein

Coronal CT image showing left retrocaval ureter with pre-caval (arrowhead) and post-caval (arrow) segments

DISCUSSION

The embryogenesis of the IVC is a complex process of development involving the posterior cardinal, the subcardinal, and the supracardinal venous systems. Aberrant complexation of these veins can result into four anomalies: Duplicated IVC, transposition of IVC to left, retroaortic left renal vein, and circum-aortic left renal vein. Left retrocaval ureter is rare, and only eight cases have been reported in the literature so far.[12345678] Left retrocaval ureter without situs and without IVC duplication is rarer with only four cases being reported in the literature.[2467] Pierro et al. reported a 0.2 to 0.5% prevalence of transposition of IVC to the left and a 0.1% prevalence of left retrocaval ureter. The management involves ureteroureterostomy, keeping in mind the altered retroperitoneal anatomy while operating.