Supernumerary Kidney with Stone: Successfully Managed with Semirigid Ureteroscopy and Laser Lithotripsy

Supernumerary kidney is a rare anomaly. Not >100 cases have been reported. It was defined by Geisinger as the "free accessory organ," which is a distinct, encapsulated, large, or small parenchymatous mass topographically related to the usual kidney by a loose cellular attachment at most and often by no attachment at times. A 28-year-old woman presented with left lower abdomen pain. On evaluation, she was found to have left supernumerary kidney with renal pelvic stone 13 × 8 mm, which was placed below the native kidney. The ureter was merging with native kidney ureter just above the vesicoureteral junction. CT angiography revealed anomalous vessels supplying the supernumerary kidney. Patient underwent semirigid ureteroscopy and laser lithotripsy and complete stone clearance was achieved. Double-J stent was removed after 2 weeks and on follow-up, there is no recurrence of stones. Supernumerary kidney is a rare congenital anomaly. Renal stone in supernumerary kidney presenting as lower abdomen pain is rarely reported. Imaging is essential to confirm the diagnosis and look for other associated anomalies. Ureteroscopy and laser lithotripsy are suitable options in such cases possibly because of low-lying kidney and location of stone in renal pelvis. Other options are mini percutaneous nephrolithotomy and retrograde intrarenal surgery.