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.

Background: Febrile neutropenia (FN) remains an important complication in pediatric cancer patients. The present study compared the efficacy of meropenem (MEPM) and piperacillin/tazobactam (PIPC/TAZ) with or without intravenous immunoglobulin (IVIG) as second-line therapy for FN in pediatric patients. Methods: As first-line treatment for FN, 394 episodes in 99 patients were randomly assigned to receive PIPC/TAZ (360 mg/kg/day, maximum 18 g/day) or MEPM (120 mg/ kg/day, maximum 3 g/day). Eighty-four episodes in 42 patients were judged as failures, and, thus, were enrolled for second-line treatment. In second-line treatment, antibiotics were switched to MEPM or PIPC/TAZ, and episodes were further randomized for treatment with or without concomitant IVIG at 100 mg/kg/day (maximum 5 g/day) for 3 consecutive days. Results: The total success rate of second-line treatment was 50.0% (52.0% in PIPC/ TAZ and 47.2% in MEPM with or without IVIG, P=0.826). The success rates of patients treated with (IVIG+ group) and without IVIG (IVIG− group) were 53.8 and 46.7%, respectively (P=0.662). In the IVIG+ group, the success rate of patients younger than 8 years old was 78.6%, which was significantly higher than that of those aged 8 years and older (40.0%, P=0.043). Conclusion PIPC/TAZ and MEPM were equally effective as second-line treatment. Concomitant IVIG was also effective, particularly in patients younger than 8 years.