Conservative management of hyperplastic and multicentric nephroblastomatosis

Purpose: The treatment of hyperplastic nephroblastomatosis remains controversial. We report the advantages of conservative management of hyperplastic and multicentric nephroblastomatosis associated with unilateral Wilms tumor (WT). Materials and Methods: During the last 10 years 48 children with unilateral WT were consecutively treated at our 2 institutions. Children with multiple solid renal masses on imaging were treated with 2-drug chemotherapy until disappearance of the lesions. Stabilization or progression of the lesions despite chemotherapy, as well as heterogeneity of the lesions on imaging, prompted nephron sparing surgery (NSS). Results: Three female infants (12, 13 and 20 months old, respectively) presented with multiple solid renal tumors at imaging. Despite chemotherapy, small and unilateral WT developed in 2 cases of hyperplastic nephroblastomatosis, which was excised. One of these infants subsequently presented with a small contralateral metachronous WT, which was excised. Both infants are disease-free with 2 normal kidneys at followup of 6 and 2 years, respectively. The third infant, who presented with unilateral multicentric WT and unilateral hyperplastic nephroblastomatosis nodules, was successfully treated with preoperative chemotherapy and enucleation of 5 tumors. Subsequently, nephrectomy was performed at another institution because the abnormal kidney outline due to NSS was misinterpreted as a recurrence of WT. She was lost to followup. Conclusions: Hyperplastic and multicentric nephroblastomatosis is not a rare lesion and is most often associated, either initially or subsequently, with WT. In some infants with multiple solid renal masses on imaging chemotherapy and for developing WT NSS may safely allow maximum sparing of the parenchyma of both kidneys.