Giant neonatal hydronephrosis of the upper pole of a complete duplicated renal system.

Ureteropelvic junction obstruction (UPJO) in the upper pole of a complete duplicated renal system is extremely rare. We report a case that was diagnosed prenatally and we review 10 cases published in the literature. Diagnoses of adrenal hematoma and cystic neuroblastoma were suspected on prenatal ultrasound, based on the severity of dilatation and the difficulty of identifying the exact origin of this anomaly. Neonatal magnetic resonance imagery (MRI) was subsequently able to show a normal adrenal gland. Surgical management is similar to that of a single-system pyeloureteral junction obstruction. Since this situation is very rare, we believe cystoscopy can be useful to confirm diagnosis of UPJO associated with complete duplication, especially in the absence of preoperative MRI. Among the 11 surgical cases previously published, seven patients underwent pyeloplasty and four heminephrectomy.