Congenital Midureteric Stenosis Mimicking Ureteropelvic Junction Obstruction: A Rare Cause of Pediatric Hydronephrosis

Background: Hydronephrosis resulting from ureteropelvic junction obstruction, the most common cause of obstructive uropathy in children, can also be caused by the rare anomaly, congenital midureteric stenosis. This case highlights the diagnostic challenge of congenital midureteric stenosis, which can clinically and radiographically mimic ureteropelvic junction obstruction. Case Presentation: We report a 5-month-old infant boy presenting with right-sided grade 3 hydronephrosis. Magnetic resonance urography and retrograde pyelography confirmed the diagnosis of congenital midureteric stenosis. At eleven months, definitive surgical correction via dismembered ureteroureterostomy was performed. Conclusions: Magnetic resonance urography can be an initial diagnostic tool to confirm Congenital midureteric stenosis along with the use of retrograde pyelography as needed.