Retro-Iliac Ureter: A Case Report of an Unusual Cause of Mid-ureteric Obstruction.

Retro-iliac ureter, a rare congenital anomaly in which the ureter courses behind the iliac vessels, is infrequently reported in the urological literature. We describe the case of a 27-year-old woman with Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome type II who presented with recurrent urinary tract infections (UTIs) and persistent right flank pain. Intraoperative retrograde pyelogram (RGP) demonstrated a markedly dilated right ureter with contrast hold-up near the sacroiliac joint. Surgical exploration confirmed a retro-iliac course of the ureter. The patient underwent successful anterior transposition and anastomosis of the ureter. This case illustrates the diagnostic challenges and surgical management of the retro-iliac ureter, particularly when associated with complex congenital anomalies such as MRKH syndrome. To our knowledge, this may be the first reported case of these two rare anomalies being combined.