Rare Presentation of Crossed Fused Ectopia with Single Ureter and Ureteropelvic Junction Obstruction: A Case Report

Abstract

Crossed fused renal ectopia (CFRE) is a congenital anomaly in which one kidney is ectopically located on the opposite side of the midline and fused with its contralateral counterpart. However, CFRE with a single ureter draining both renal moieties is an exceptionally rare variant. We report on the case of a 12-year-old boy who presented with recurrent episodes of right flank pain. Ultrasonography and subsequent contrast-enhanced CT revealed that the left kidney was located on the right side, fused with the right kidney. Both renal pelvises were fused, forming a single pelvicalyceal system that drained through a solitary ureter entering the urinary bladder on the right side. This case highlights the characteristic imaging features of this unusual congenital anomaly, emphasizing the crucial role of CT in its accurate diagnosis and preoperative evaluation.