Retrocaval ureter successfully treated with laparoscopic ureteroplasty and functionally evaluated using Tc-99 m MAG-3 renal scintigraphy: a case report

BACKGROUND: Retrocaval ureter (RCU) is a rare congenital anomaly in which the ureter passes posterior to the inferior vena cava (IVC), causing urinary obstruction. The treatment generally involves surgical ureteral reconstruction. We report a case of RCU successfully treated with laparoscopic ureteroplasty, with favorable postoperative outcomes confirmed using technetium-99 m mercaptoacetyltriglycine (Tc-99 m MAG-3) renal scintigraphy. CASE PRESENTATION: A 22-year-old Japanese man presented with a 3-year history of dull right flank pain. Physical examinations and basic laboratory investigations returned normal results. Abdominal ultrasound identified hydronephrosis on the right side, and computed tomography urography revealed a characteristic "S"-shaped or "fishhook"-shaped right ureter, resulting in a diagnosis of RCU Type I. The patient was treated with laparoscopic ureteroplasty. Postoperatively, the hydronephrosis has been resolved and his symptoms have improved. Tc-99 m MAG-3 renal scintigraphy after 3 years postoperatively revealed demonstrating improvement in the delayed excretion from the right ureter observed before surgery. CONCLUSIONS: Surgical treatment for symptomatic RCU is effective in relieving symptoms and preventing renal function deterioration. Laparoscopic ureteroplasty offers a minimally invasive approach with favorable outcomes. Tc-99 m MAG-3 renal scintigraphy serves as a valuable tool for the functional assessment of laparoscopic ureteroplasty in the management of RCU.