Bilateral Pelvic Ectopic Kidneys With Bicornuate Uterus: A Rare Case of Congenital Association Complicated by Urolithiasis and Pregnancy

Bilateral pelvic ectopic kidneys represent an exceptionally rare congenital anomaly. Their co-occurrence with Müllerian anomalies reflects shared embryological disruption of the metanephric and paramesonephric systems and carries significant clinical implications, particularly during pregnancy. A 37-year-old woman with no previous urological history presented with left flank pain. Renal ultrasound demonstrated bilateral pelvic ectopic kidneys and a 5 mm non-obstructing left renal calculus. Oral analgesia and increased fluid intake were advised. Repeat ultrasound six months later confirmed spontaneous passage of the calculus with no residual stone burden. The patient was concurrently under gynecological follow-up for a bicornuate uterus. A non-contrast pelvic magnetic resonance imaging (MRI), performed by the gynecology department, to characterize the uterine anomaly and deferred to a non-contrast protocol due to concurrent pregnancy, confirmed bilateral ectopic kidneys situated in the presacral and rectovaginal pouch of Douglas with aberrant vascular supply arising near the common iliac artery bifurcation. Renal function tests and urinalysis remained within normal limits throughout the follow-up period, including during pregnancy. The patient delivered at 37+3 weeks of gestation by elective cesarean section without maternal or urological complications and was maintained under urological surveillance post-partum, with computed tomography urography planned for full anatomical delineation. This case illustrates a rare embryologically linked combination of bilateral pelvic ectopic kidneys and a bicornuate uterus. Awareness of this association may aid multidisciplinary management across urology, gynecology, and obstetrics. Consideration should be given to evaluation for co-existing Müllerian anomalies when congenital renal anomalies are identified, and vice versa.