Recurrent metanephric stromal tumor in an infant.

A 9-month-old boy underwent nephrectomy for a renal mass. Congenital mesoblastic nephroma was diagnosed, and the patient received postoperative chemotherapy. Tumor recurred 6 months later as a scrotal mass. After orchiectomy, diagnosis of metanephric stromal tumor (MST) was made; review of the nephrectomy specimens confirmed this diagnosis. No additional treatment was given, and the child is alive and well 31 months later. Taking into account the histopathological entity of MST in the differential diagnosis of stromal renal tumors in childhood can spare the patient further, potentially toxic, treatment even in the case of relapse, as reported here for the first time.