Allogeneic hematopoietic stem cell transplantation (HSCT) is performed as a curative treatment for children with nonmalignant diseases, such as bone marrow failure syndromes and primary immunodeficiencies. Because graft-versus-host-disease (GVHD) is a major factor affecting survival probability and quality of life after HSCT, the availability of HLA-matched donors restricts the application of HSCT. Recently, HSCT with post-transplantation cyclophosphamide (PTCy) has emerged as a potent method to prevent GVHD after HSCT from HLA-haploidentical donors, and some studies have suggested the safety of PTCy-HSCT for nonmalignant diseases. We conducted a prospective clinical trial aiming to help confirm the safety of HSCT and further reduction of GVHD using a combination of PTCy and low-dose antithymocyte globulin (ATG) from HLA-mismatched related donors for children with nonmalignant diseases. Six patients underwent HSCT and achieved engraftment at a median of 14.5 days, and no patient developed severe acute GVHD. All patients had sustained donor chimerism without developing chronic GVHD at the last follow-up. In conclusion, HSCT with PTCy and low-dose ATG from an HLA-mismatched related donor were feasible to control GVHD for nonmalignant diseases in the children involved in our study.

A 42-year-old female presented with right back pain. The CT scan revealed a 72-mm space-occupying lesion in the middle portion of the right kidney. No metastasis was proven. She underwent laparoscopic radical nephrectomy and lymph node disection. The histopathological examination revealed a high-grade primitive small round tumor the cells of which were strongly positive for CD99 and vimentin. Fluorescence in situ hybridization analysis using a DNA probe for the Ewing sarcoma breakpoint region 1 (EWSR 1) on chromosome 22g12 revealed a rearrangement of the EWSR 1 locus. The diagnosis was Ewing's sarcoma / primitive neuroectodermal tumor of the kidney. She underwent 13 cycles of chemotherapy, and has no evidence of recurrence 19 months after surgery.

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Juvenile xanthogranulomatosis (JXG) is a rare histiocytic disease that is usually limited to the skin, but some JXG cases involve other organs. JXG involving the central nervous system (CNS) is rare and its treatment is inadequate. The optimum treatment for refractory JXG involving the CNS remains unknown. We report here a case of refractory pediatric extracutaneous JXG (extra-JXG) involving the CNS with multiple intracranial masses treated with 2-chlorodeoxyadenosine resulting in achievement of long-term complete remission. 2-Chlorodeoxyadenosine, with favorable CNS penetration in the cerebrospinal fluid, is apparently an effective treatment for extra-JXG and systemic JXG (sJXG) with CNS involvement.

Treatment strategy for trilateral retinoblastoma (TRb: very rare RB with brain tumor) or retinoblastoma with central nervous system (CNS) involvement is not established yet. We retrospectively reviewed our seven cases of these rare almost fatal tumors. Their ages at diagnosis are 0y3m-1y10m (median 1y3m) (Male 4, Female 3). Only one had RB family history. Their affected eyes were bilateral 3, unilateral 3 and no 1. Their CNS involvements were suprasellar tumor 4, pineal tumor 1 and cerebrospinal fluid (CSF) cytology positive 2. Three of the suprasellar tumor patients had spinal metastasis. Four of the seven patients were TRb and one were genetically classified suprasellar retinoblastoma. All of them were treated with chemotherapy and four received high-dose chemotherapy. Three brain tumors of four TRb almost disappeared with chemotherapy. Two of them also received radiotherapy but relapsed. Although one radiation-free long-term TRb survivor developed secondary osteosarcoma, he got remission again and live 5 more years. One CSF positive Rb patient with chiasm invasion died of disease 11 months later. The other patient had no chiasm invasion nor CSF involvement at diagnosis, but his CSF cytology turned to positive after his second cycle of chemotherapy. He got remission with radiotherapy and high-dose chemotherapy, and alive without disease for 4 years. 2-year RFS and 2-year OS of all patients were 40% and 60%. Although our TRb patients responded to chemotherapy, it was difficult to avoid radiotherapy except one. Data accumulation is necessary for better treatment of these cancer-predisposed patients.