ABSTRACT
Nephroblastomatosis (NBM) is a precursor of Wilms tumor. We herein report a case in which Wilms tumor was initially suspected and the affected kidney was removed.The tumor was subsequently diagnosed as intralobar NBM and a favorable outcome was achieved with postoperative chemotherapy. A 2-year-old boy who presented with gross hematuria was found to have an enlarged left kidney with hydronephrosis.Needle biopsy of the left kidney suggested Wilms tumor and left nephrectomy was performed. The tumor was histopathologically diagnosed as intralobar NBM.Although NBM is regarded as a precancerous lesion, a definite treatment plan has not yet been established. In the present case, we used a similar chemotherapy regimen to that for Wilms tumor. Eight years after the completion of chemotherapy, Wilms tumor has not developed or recurred. Appropriate management plans need to be developed by accumulating similar cases.