A rare case of non-fused inferior dysplastic crossed renal ectopia with obstructing ectopic ureterocele in an adult: diagnostic and therapeutic considerations

Crossed renal ectopia (CRE) is the second most common renal fusion anomaly after horseshoe kidney, typically diagnosed antenatally. However, non-fused CRE is rare, accounting for only 10% of cases. Ureterocele, an uncommon congenital anomaly, is rarely associated with non-fused CRE and can cause significant urinary obstruction. We report the case of a 27-year-old male who presented with persistent lower urinary tract symptoms and weak urinary flow since childhood. Previous evaluations failed to identify an underlying cause. Magnetic resonance imaging (MRI) urography revealed a non-fused left renal ectopia with an ectopic ureterocele obstructing the bladder neck. Dimercaptosuccinic acid (DMSA) scintigraphy confirmed a non-functioning dysplastic left kidney, while voiding cystourethrography ruled out vesicoureteral reflux. The patient underwent holmium:yttrium-aluminum-garnet (YAG) laser incision of the ureterocele, which resulted in the drainage of a significant amount of pus, despite the fact that bacterial growth was not detected on culture. Postoperatively, the patient’s symptoms improved considerably, with an increase in maximum urinary flow rate (Qmax: 7 ml/s to 14 ml/s) and a reduction in International Prostate Symptom Score (IPSS: 31 to 9) within one month. This case underscores the importance of considering congenital urinary anomalies in patients with long-standing voiding dysfunction. To our knowledge, this is the first reported adult case of non-fused CRE with an ectopic ureterocele causing bladder outlet obstruction.