Unusual Presentation of Duplex Kidneys: Ureteropelvic Junction Obstruction.

. Ureteropelvic junction obstruction (UPJO) is rarely associated with a duplex collecting system. We review this unusual anomaly in terms of presentation, diagnostic evaluation, and surgical management. . We retrospectively reviewed the medical records of patients diagnosed with a duplex system with UPJO. . Sixteen patients (6 girls, 10 boys) with 18 moieties were treated surgically and four patients were treated conservatively. The median age at surgery was two years (range, 2 months to 7 years). The lower pole and upper moiety were affected in 12 and two kidneys, respectively, and both were affected in two patients. The anomaly was right-sided in 12 moieties and left-sided in six. The duplication was incomplete in seven patients and complete in nine. The mean renal pelvis diameter at the time of surgery was 25.6 (range 11-48 mm) mm by USG. The mean renal function of the involved moiety was 28.3% before surgery. Management included pyelopyelostomy or ureteropyelostomy in six moieties, dismembered pyeloplasty in eight moieties, heminephrectomy in four cases, and simultaneous upper heminephrectomy and lower pole ureteropyelostomy in one patient. . There is no standard approach for these patients and treatment should be individualized according to physical presentation, detailed anatomy, and severity of obstruction.