Unexpected proximal ureteral stricture in a 5-year-old girl: case report.

Congenital ureteral stricture is a rare but important differential diagnosis in antenatal hydronephrosis, often mistaken for ureteropelvic junction obstruction. We report the case of a 5-year-old girl who underwent surgery for suspected ureteropelvic junction obstruction based on imaging findings, including renal ultrasound and scintigraphy. Intraoperatively, the pyeloureteral junction appeared normal, but a proximal ureteral stricture was discovered 4 cm distal to the renal pelvis. Surgical management consisted of resecting the narrowed segment and performing a tension-free end-to-end ureteral anastomosis over a double-J stent. This case highlights the diagnostic limitations of standard imaging techniques in detecting ureteral anomalies and emphasizes the importance of accurate diagnosis and optimal management to preserve renal function.