Surgical ureteric injury is rare and often unsuspected for a long time. We present a child in whom an abdominal neuroblastoma was completely excised, but during surgery the left ureter was transected and anastomosed. One month later, during postoperative disease staging, abnormal (123)I-MIBG accumulation was observed in the left renal cortex and the left side of the abdomen. These findings were consistent with acute total obstruction and urinoma formation and were subsequently confirmed by renography and MRI. Despite treatment efforts, a significant amount of left renal mass and function were lost over the following months. These unusual findings are new additions to the literature regarding potential false-positive interpretations of (123)I-MIBG scans.