Background Stem cell transplantation (SCT) outcomes have improved over the last three decades, with many patients being rescued with this treatment. However, improved outcomes have led to issues with long-term sequelae. One of these sequelae in children is renal dysfunction, an index of which is estimated using glomerular filtration rate (eGFR). Procedure We retrospectively analyzed eGFR in 83 pediatric patients who received SCT. Data from all patients extended up to 12 months or more post SCT. The median follow-up time was 127.7 months (range 12.0-268.8 months). Results Eighteen patients (21.7%) had low eGFR (<90 ml/min/1.73 m(2)) post SCT. Cumulative incidence of low eGFR was 25.8 +/- 2.0%. Nine (10.6%) patients had a low eGFR pre-SCT. However, pre- and post-SCT incidence of low eGFR were not correlated. Meanwhile, only two patients (2.4%) exhibited severe renal dysfunction, with eGFRs < 60 ml/min/1.73 m(2). Independent risk factors for low eGFR were solid tumor and use of fludarabine. Moreover, age at SCT >= 7 years was also a long-term post-SCT risk factor for low eGFR in all patients. Conclusion Independent post-SCT long-term risk factors for low eGFR in children were solid tumor and use of fludarabine. Moreover, age at SCT >= 7 years was a post-SCT long-term risk factor for low eGFR across all patients.

Extrarenal nephroblastoma (ERNB) is a rare disease. We report a case of ERNB in a 4-year-old boy complaining of abdominal pain and vomiting. Imaging showed a retroperitoneal mass and left hydronephrosis. The mass was completely removed by surgery. The pathologic diagnosis was ERNB with favorable histology. Postoperative chemotherapy was administered for 24 weeks with actinomycin D, vincristine, and doxorubicin. No signs of recurrence were found for the next 3 years. We consider 53 reports of ERNB and our own. Median age at diagnosis was 42 months. The most common site is the retroperitoneal space (44.4%), followed by the uterus (14.8%).

Inhibitor development is one of the major problems in hemophilia patients. Whereas the inhibitor incidence in hemophilia A is estimated to be as high as 25-30%, it appears to be less frequent in hemophilia B, occurring in about 1-3% of hemophilia B patients. There are only a few case reports about immune tolerance induction (ITI) for hemophilia B patients. The present report describes ITI with rituximab in a patient with severe hemophilia B and inhibitor. The patient was diagnosed with severe hemophilia B at 9 months. He received prophylactic replacement therapy with plasma-derived factor IX (pd FIX). After 19 exposure days, inhibitor of factor IX was detected in his plasma, and replacement therapy was stopped. However, as he suffered from intracranial hemorrhage at the age of 1 year, he underwent first ITI at the age of 1 year. Unfortunately, this failed to reduce the level of the inhibitor, and this strategy was stopped after 2 years. Second ITI with pd FIX also failed. At the age of 14 years, ITI with rituximab was performed after obtaining informed consent. The patient received rituximab 375 mg/m(2) once a week for four doses and received 40 u/kg of pd FIX every day. At 4 weeks after the start of ITI with rituximab, the level of the inhibitor of factor IX was diminished and was undetectable for 1 year after therapy. In this patient, ITI with rituximab was well tolerated and effective. This method should be considered for patients with hemophilia B and inhibitor.