99mTc-Labeled Diethylenetriamine Pentaacetic Acid Unveils a Hernia: Renal Scintigraphy in Late Transplant Obstruction

Ureteral obstruction is a frequent urologic complication after kidney transplant and usually occurs in the early postoperative period. Inguinal herniation of the transplanted ureter is a rare but potentially correctable cause of late obstructive uropathy. We report a 57-year-old male kidney transplant recipient who presented with hydronephrosis and acute kidney injury. Ultrasonography showed moderate to severe hydronephrosis of the renal allograft. Renal scintigraphy with 99mTc-diethylenetriamine pentaacetic acid revealed delayed tracer transit and abnormal radiotracer accumulation inferior to the urinary bladder, suggestive of distal ureteral obstruction. Abdominopelvic computed tomography confirmed herniation of the distal transplanted ureter into a right inguinal hernia. This case highlights the diagnostic value of 99mTc-diethylenetriamine pentaacetic acid renal scintigraphy for identification of uncommon causes of late ureteral obstruction in kidney transplant recipients. Inguinal herniation of the transplanted ureter should be considered in patients with posttransplant hydronephrosis and compatible clinical findings.