Type II retrocaval ureter causing hydronephrosis in a cat: case report

V.G.P Albernaz,U.I Tasqueti,J.G Quitzan,L.C Miara,F Meyer,I.A Fabris

doi:10.1590/1678-4162-10252

Abstract

ABSTRACT Retrocaval ureter (RU) is an abnormal embryonic development of the caudal vena cava (CVC) that leads the ureter to be entrapped dorsal to the CVC. In most cases there is no clinical impact; however, it can cause hydronephrosis. We report a rare case of type II symptomatic retrocaval ureter in a feline treated with nephroureterectomy. A 4-year-old, intact male, mixed breed cat was submitted to abdominal ultrasound and severe right hydronephrosis was diagnosed, with no signs of obstruction. We performed an exploratory celiotomy, in which a displacement of the right ureter dorsal to the CVC was observed. The animal was treated with ureteronephrectomy and recovered well. No intraluminal cause was found, and a urethral catheter could be easily inserted across the ureter length. The real clinical relevance of the RU is unknown, since it is a common find in post-mortem examination without kidney impact and, when significant, is often associated to other causes of ureteral obstructions, such as calculi and strictures. Additionally, in humans, type II RU seldom develops obstruction and hydronephrosis. In our case, due to absence of other causes of obstruction, probably mechanical compression of the CVC against the psoas muscle caused the hydronephrosis.

Highlights

Retrocaval ureter (RU), known as circumcaval ureter, is a rare congenital anomaly of the caudal vena cava (CVC), in which the ureter is abnormally displaced dorsal to the CVC and between the aorta and dorsal muscles (Salonia et al, 2006; Basok et al, 2008; Bélanger et al, 2014)
We report a rare case of type II symptomatic retrocaval ureter in a feline treated with nephroureterectomy
All image exams, surgical exploration, and ureteral patency test with a urinary catheter did not found any calculi or stricture, suggesting that the mechanical compression of the CVC and the psoas muscle could be the cause of the megaureter and hydronephrosis, as occurs in human urology (Salonia et al, 2006)

Summary

INTRODUCTION

Retrocaval ureter (RU), known as circumcaval ureter, is a rare congenital anomaly of the caudal vena cava (CVC), in which the ureter is abnormally displaced dorsal to the CVC and between the aorta and dorsal muscles (Salonia et al, 2006; Basok et al, 2008; Bélanger et al, 2014). The most common is type I, where an acute medial deviation of the ureter causes a “Fish-hook” deformity leading often to symptomatic patients; and the rare, generally asymptomatic type II, when the ureter passes around the CVC at the ureteropelvic junction (Basok et al 2008; Salonia et al, 2006). This case report aims to describe a rare case of feline type II RU causing severe hydronephrosis, without any other obstructive cause and successfully treated with nephroureterectomy. The patient remained stable, without any signs compatible with the disease

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CONCLUSION