A case of malignant rhabdoid tumor mimicking yolk sac tumor.

Malignant rhabdoid tumors (MRTs) are rare, highly aggressive embryonal neoplasms caused by biallelic alterations of the SMARCB1 gene. MRTs may occur in any soft tissue, but extracranial extrarenal MRTs are extremely rare. Diagnosis of MRTs in unusual locations and with an uncharacteristic cytomorphology that mimics other tumors is difficult. This was an atypical case of MRT in a 15-year-old female with tumors that closely resembled yolk sac tumors. It was extremely challenging to diagnose the tumors without confirming the SMARCB1 status.

[Successful management of acute chest syndrome in a patient with sickle cell disease].

Although sickle cell disease (SCD) is common in endemic areas of malaria, it is one of the rare diseases in Japan. Hence, SCD and its complications are not well established in Japan. An 11-year-old girl was referred to the specialized pediatric center of our hospital. She was born in Brazil and diagnosed with SCD after birth. However, she did not have a routine checkup in Japan. Owing to influenza viral infection, she developed vaso-occlusive pain crisis (VPC) and needed hospitalization for pain management. After admission, she developed dyspnea, needing intratracheal intubation and mechanical ventilation. A chest X-ray revealed bilateral pulmonary infiltration, suggesting acute chest syndrome (ACS) complicated with SCD. Intensive care, including transfusion of red blood cells, successfully improved her condition. Reportedly, half cases of VPC develop ACS, and the mortality of ACS is very high. Hence, when managing VPC cases, the prevention of ACS, through transfusion of red blood cells or infectious control, is imperative. Thus, Japanese hematologists and pediatricians should recognize SCD and its complications owing to an anticipated increase of foreign travelers or migrants in the future.

[Allogeneic hematopoietic stem cell transplantation using myeloablative conditioning including total body irradiation for pediatric acute lymphoblastic leukemia: a single-center retrospective analysis].

This study aimed to investigate the clinical outcomes of hematopoietic stem cell transplantation (HSCT) with total body irradiation-based myeloablative conditioning (TBI-MAC) in pediatric patients with acute lymphoblastic leukemia (ALL). We retrospectively examined patients with ALL who underwent HSCT with TBI-MAC from January 2000 to August 2016 at our institute. We enrolled 67 patients with a median follow-up period of 8 years. The 5-year event-free survival (EFS) and overall survival (OS) were 51.2% and 59.6%, respectively. At the first complete remission, HSCT exhibited significantly superior EFS and OS in our patients than that in patients with other diseases. We encountered 57.9% of patients with at least one late complication. Major late complications were short stature (26.3%) and hypogonadism (18.4%). While late complications were observed in several recipients of HSCT, late complication-related deaths occurred in three patients. The TBI-MAC regimen led to favorable clinical outcomes in pediatric patients with ALL who underwent HSCT. Thus, proper evaluation and management of late complications are mandatory.

Safety of Live Attenuated High-Titer Varicella-Zoster Virus Vaccine in Pediatric Allogeneic Hematopoietic Stem Cell Transplantation Recipients.

Hematopoietic stem cell transplantation (HSCT) recipients have a high risk of varicella-zoster virus (VZV) infections. Although VZV vaccination may be beneficial in preventing VZV infections, data on safety and efficacy of VZV vaccines in HSCT recipients, particularly of zoster vaccine, are limited. We report our experience with the use of a single dose of an Oka strain high-titer zoster-equivalent varicella vaccine in pediatric allogeneic HSCT recipients. We administered the high-titer VZV vaccine to 31 pediatric allogeneic HSCT recipients without vaccine-type VZV infections. One patient developed varicella due to wild-type VZV 13 days after vaccination. No zoster developed after vaccination during a median follow-up period of 4.8 years from vaccination. No other adverse effects were observed. Eighteen of the 31 patients (58.1%) were seropositive after vaccination. Seventeen patients were vaccinated within 24 months after HSCT; the seropositivity of these patients did not significantly differ from that of patients vaccinated > 24 months after HSCT. VZV vaccination may be a safe and beneficial approach in preventing VZV infections after HSCT.

Addition of High-Dose Cytarabine to Fludarabine-Based Conditioning for Hematopoietic Stem Cell Transplantation for Treating Fanconi Anemia Patients with Advanced Myeloid Malignancy: A Single-Center Experience and Literature Review.

The complication of Fanconi anemia (FA) with acute leukemia is rare and challenging to treat because of high relapse rates, despite the improved outcome of hematopoietic stem cell transplantation with fludarabine-based conditioning for treating FA patients with hematological abnormalities. We added high-dose cytarabine to fludarabine-based conditioning to promote an enhanced antitumor effect and successfully subjected 4 patients with FA, including 3 with acute leukemia, to hematopoietic stem cell transplantation. All patients remain alive without treatment-related mortality or evidence of disease. Adding high-dose cytarabine to fludarabine-based conditioning may be tolerable and effective for treating FA patients with acute leukemia.

Low Frequency of Programmed Death Ligand 1 Expression in Pediatric Cancers.

Programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway blockade has become a promising therapeutic target in adult cancers. We evaluated PD-L1 expression and tumor-infiltrating CD8(+) T cells in formalin-fixed, paraffin-embedded tumor specimens from 53 untreated pediatric patients with eight cancer types: neuroblastoma, extracranial malignant germ cell tumor, hepatoblastoma, germinoma, medulloblastoma, renal tumor, rhabdomyosarcoma, and atypical teratoid/rhabdoid tumor. One rhabdomyosarcoma with the shortest survival exhibited membranous PD-L1 expression and germinoma contained abundant tumor-infiltrating CD8(+) T cells and PD-L1-positive macrophages. The PD-1/PD-L1 pathway tended to be inactive in pediatric cancers.

Successful switching from eltrombopag to romiplostim in a pediatric patient with refractory chronic ITP.

Herein, we report a successful treatment experience with romiplostim in a child with immune thrombocytopenia (ITP) refractory to eltrombopag. A 9-year-old female developed chronic ITP, which was refractory to standard treatments, including intravenous immunoglobulin, cepharanthine and splenectomy, and she thus became dependent on prednisolone (PSL). At age 12 years, eltrombopag was started, but failed to increase her platelet count. Another thrombopoietin receptor agonist (TPO-RA), romiplostim, possibly having a different mechanism of action, was then administered. Platelet counts increased and PSL could thus be terminated. Our case suggests TPO-RA alteration to potentially be effective for chronic refractory ITP.

Long-term follow-up results of the observation program for neuroblastoma detected at 6-month mass screening.

We conducted an observation program of neuroblastoma in infants, detected by mass screening at 6 months of age; we followed up with them for 15 years. No recurrence was observed after disappearance of tumors, and persistent tumors showed no malignant transformation or metastasis. Histology of the resected tumors showed age-related differentiation.

Cisplatin-induced hearing loss: the need for a long-term evaluating system.

Cisplatin is an effective chemotherapeutic agent against pediatric cancers; however, ototoxicity is a concern. This study describes the frequency, severity, and clinical course of hearing loss in Japanese pediatric patients treated with cisplatin-based multimodal therapy. A total of 55 children who received cisplatin-based therapy from 1983 to 2012 underwent audiologic evaluations. Data were analyzed to determine the onset, time-to-progression, and severity of hearing loss. Thirty-five patients, 12 of 16 older patients (4 y or older), and 23 of 39 younger patients (under 4 y), including 7 of 8 patients treated with cisplatin, carboplatin, and radiotherapy, developed hearing loss. Ten of 18 patients who received a cumulative cisplatin dose of <360 mg/m developed hearing loss at a minimum dose of 200 mg/m. Median time to onset after the last cisplatin dose was 71 days; 6 patients developed hearing loss after ≥2 years. Four patients required hearing aids, 6 patients developed progressive hearing loss with time, and 4 patients exhibited persistent hearing failure at low frequencies. Risk factors for acquired hearing loss and its severity may be associated with a combination of factors such as cisplatin and carboplatin therapy, radiotherapy, age at diagnosis, and genetic background. Our results suggested that all pediatric patients treated with cisplatin would have their hearing evaluated regularly, irrespective of the cumulative cisplatin dose as a suggestion, and that further prospective studies regarding ototoxicity including genetic polymorphisms analysis were required.

The effect of the order of total body irradiation and chemotherapy on graft-versus-host disease.

BACKGROUND: Graft-versus-host disease (GVHD) is one of the most important complications in allogeneic hematopoietic stem cell transplantation. Intensity of conditioning regimen is one of the risk factors, which is associated with acute GVHD, and some studies have shown that alteration of the administration order from busulfan to cyclophosphamide to cyclophosphamide to busulfan could decrease cytokine levels and organ toxicity. METHODS: To investigate whether the order of total body irradiation (TBI) and chemotherapy is associated with the incidence of GVHD, we reviewed the charts of 124 consecutive hematopoietic stem cell transplantation, which was performed in Saitama Children's Medical Centre and University of Tokyo Hospital between 1995 and 2010. RESULTS: TBI performed before chemotherapy (TBI-CT) showed an increased risk for grades II to IV acute GVHD (61.6±7.8%) compared with the TBI performed after chemotherapy (CT-TBI) (42.8±7.2%) (P=0.048), whereas the incidence of grades III and IV GVHD were similar between TBI-CT and CT-TBI. Multivariate analysis showed that TBI-CT was associated with a higher risk of grades II to IV acute GVHD. However, overall survival probability of TBI-CT cohort was similar to that of CT-TBI cohort. CONCLUSIONS: Our results provided a novel risk factor for acute GVHD, which can be easily controlled by the physician.

Unrelated cord blood and bone marrow transplantation in pediatric leukemia.

To investigate the role of cord blood as an alternative stem cell source for hematopoietic stem cell transplantation for pediatric acute leukemia, we retrospectively analyzed the outcomes of 35 unrelated cord blood transplantations (UCBT) and 56 unrelated bone marrow transplantations (UBMT) with myeloablative conditioning. The 5 year overall survival (OS) probability was 49.8% (95% confidence interval [95%CI]: 35.6-62.4%) for UBMT and 53.8% (95%CI: 34.0-70.1%) for UCBT (P = 0.92). The 5 year event-free survival (EFS) probability was 47.3% (33.6-59.8%) for UBMT and 33.0% (15.9-51.2%) for UCBT (P = 0.38). OS and EFS were not significantly different between the groups. On multivariate analysis there was no significant difference between the groups. In conclusion, UCBT can have a role as important as that of UBMT in pediatric acute leukemia.

NUP98-NSD1 gene fusion and its related gene expression signature are strongly associated with a poor prognosis in pediatric acute myeloid leukemia.

The cryptic t(5;11)(q35;p15.5) creates a fusion gene between the NUP98 and NSD1 genes. To ascertain the significance of this gene fusion, we explored its frequency, clinical impact, and gene expression pattern using DNA microarray in pediatric acute myeloid leukemia (AML) patients. NUP98-NSD1 fusion transcripts were detected in 6 (4.8%) of 124 pediatric AML patients. Supervised hierarchical clustering analyses using probe sets that were differentially expressed in these patients detected a characteristic gene expression pattern, including 18 NUP98-NSD1-negative patients (NUP98-NSD1-like patients). In total, a NUP98-NSD1-related gene expression signature (NUP98-NSD1 signature) was found in 19% (24/124) and in 58% (15/26) of cytogenetically normal cases. Their 4-year overall survival (OS) and event-free survival (EFS) were poor (33.3% in NUP98-NSD1-positive and 38.9% in NUP98-NSD1-like patients) compared with 100 NUP98-NSD1 signature-negative patients (4-year OS: 86.0%, 4-year EFS: 72.0%). Interestingly, t(7;11)(p15;p15)/NUP98-HOXA13, t(6;11)(q27;q23)/MLL-MLLT4 and t(6;9)(p22;q34)/DEK-NUP214, which are known as poor prognostic markers, were found in NUP98-NSD1-like patients. Furthermore, another type of NUP98-NSD1 fusion transcript was identified by additional RT-PCR analyses using other primers in a NUP98-NSD1-like patient, revealing the significance of this signature to detect NUP98-NSD1 gene fusions and to identify a new poor prognostic subgroup in AML.

Clofarabine-based combination chemotherapy for relapse and refractory childhood acute lymphoblastic leukemia.

Clofarabine, one of the key treatment agents for refractory and relapsed acute lymphoblastic leukemia (ALL), achieves a remission rate of approximately 30% with single-agent clofarabine induction chemotherapy. However, a remission rate of approximately 50% was reported with a combination chemotherapy regimen consisting of clofarabine, etoposide, and cyclophosphamide. We treated two cases with refractory and relapsed ALL with combination chemotherapy including clofarabine; one was an induction failure but the other achieved remission. Both cases developed an infectious complication (NCI-CTCAE grade 3) and body pain with infusion. Prophylactic antibiotic and opioid infusions facilitated avoiding septic shock and pain. Further investigation of such cases is required.

Characterization of genetic lesions in rhabdomyosarcoma using a high-density single nucleotide polymorphism array.

Rhabdomyosarcoma (RMS) is a common solid tumor in childhood divided into two histological subtypes, embryonal (ERMS) and alveolar (ARMS). The ARMS subtype shows aggressive clinical behavior with poor prognosis, while the ERMS subtype has a more favorable outcome. Because of the rarity, diagnostic diversity and heterogeneity of this tumor, its etiology remains to be completely elucidated. Thus, to identify genetic alterations associated with RMS development, we performed single nucleotide polymorphism array analyses of 55 RMS samples including eight RMS-derived cell lines. The ERMS subtype was characterized by hyperploidy, significantly associated with gains of chromosomes 2, 8 and 12, whereas the majority of ARMS cases exhibited near-diploid copy number profiles. Loss of heterozygosity of 15q was detected in 45.5% of ARMS that had been unrecognized in RMS to date. Novel amplifications were also detected, including IRS2 locus in two fusion-positive tumors, and KRAS or NRAS loci in three ERMS cases. Of note, gain of 13q was significantly associated with good patient outcome in ERMS. We also identified possible application of an ALK inhibitor to RMS, as ALK amplification and frequent expression of ALK were detected in our RMS cohort. These findings enhance our understanding of the genetic mechanisms underlying RMS pathogenesis and support further studies for therapeutic development of RMS.

Aggressive transformation of juvenile myelomonocytic leukemia associated with duplication of oncogenic KRAS due to acquired uniparental disomy.

A small fraction of cases of juvenile myelomonocytic leukemia (JMML) develop massive disease activation. Through genomic analysis of JMML, which developed in an individual with mosaicism for oncogenic KRAS mutation with rapid progression, we identified acquired uniparental disomy at 12p. We demonstrated that duplication of oncogenic KRAS is associated with rapid JMML progression.

Prophylactic administration of prothrombin complex concentrates for congenital prothrombin deficiency with a novel frameshift mutation, prothrombin saitama.

Prothrombin (Factor II, FII) deficiency is an extremely rare autosomal recessive condition with an estimated incidence of 1:2 million. As severe and life-threatening bleeding is rare in FII deficiency, on demand therapy with administration of prothrombin complex concentrates (PCCs) or fresh frozen plasma is generally performed, and prophylactic therapy for FII deficiency has been reported in only three cases. Thus, its optimal dosage and schedule has remained uncertain. Here we report a case of severe prothrombin deficiency with a novel frameshift mutation of the F2 gene, who was started on prophylactic administration.

Delayed short-term administration of granulocyte colony-stimulating factor is a good mobilization strategy for harvesting autologous peripheral blood stem cells in pediatric patients with solid tumors.

PBSCs have become the preferred source of autologous stem cells for supporting high-dose chemotherapy in childhood solid tumors. The aims of this retrospective study were to examine the optimal timing for administration of G-CSF after chemotherapy and to identify the patients from whom an optimal dose of PBSCs can be harvested. We evaluated the timing of G-CSF administration for harvesting PBSCs in patients with childhood solid tumors. G-CSF was administered immediately after chemotherapy in eight patients (11 harvests, long-term group) and following recovery from hematological nadirs in 17 patients (21 harvests, short-term group). The median duration of G-CSF administration was 22 vs. 5 days, respectively (p < 0.005), and the dose of harvested CD34(+) cells (×10(6) /kg) was 1.4 vs. 2.9, respectively (p = 0.023). Our results suggest that short-term G-CSF administration is a good strategy for harvesting PBSCs in these patients.

Kasabach-Merritt phenomenon: a report of 11 cases from a single institution.

BACKGROUND: Kasabach-Merritt phenomenon (KMP) is a rare condition and optimal treatments have not yet been established, especially for cases that are unresponsive to first-line therapy. We retrospectively reviewed 11 KMP cases treated over the past 13 years in our institute. OBSERVATIONS: With the exception of 1 case, steroids were administered as the first-line therapy. Eight cases required second-line or third-line therapy. The effective salvage therapies include interferon (n=1), radiotherapy (n=1), and chemotherapy (n=5). One case continues to depend upon chemotherapy. Three refractory cases were therapy dependent over 1 year of age, whereas 8 were treated effectively by 6 months of age. CONCLUSIONS: Chemotherapy seems to be the most effective therapy for steroid-resistant KMP cases.

Long-term survivor of relapsed stage IV malignant rhabdoid tumor of the kidney.

The prognosis for metastatic malignant rhabdoid tumor (MRT) is poor, and metastatic (stage IV) MRT was resistant to conventional treatment, with less than 20% of cure rate. Moreover, there have been no reports of patients who have survived relapsed stage IV MRT. Here we report a long-term survivor of relapsed MRT with lung metastasis at diagnosis. He was diagnosed as MRT of the kidney at 5-month-old. After resection of the renal tumor, he was treated with ICE (ifosfamide, carboplatin, and etoposide), total abdominal irradiation 10.8 Gy and high-dose chemotherapy using thiotepa and melphalan. Six months after initial treatment, a relapse in the lung was detected, and he received chemotherapy including doxorubicin/pirarubicin for 78 weeks. He is alive at five years of follow up, without any evidence of disease. Our report suggests the important role of anthracycline in treatment of MRT.

[The feasibility of Erwinia asparaginase for pediatric patients who developed an allergic reaction to E.coli asparaginase during treatment of acute lymphoblastic leukemia].

Asparaginase (ASNase) is one of the most important key drugs in the treatment of acute lymphoblastic leukemia (ALL). However, clinical hypersensitivity reactions often occur and lead to the discontinuation of ASNase treatment. Here, we report a retrospective study of 68 Erwinia ASNase (Erw-ASNase) administrations in 11 patients with childhood ALL who developed allergic reactions to E.coli-ASNase in our hospital between 2006 and 2012. The median age of the patients was 6 (range, 0 to 14). Erw-ASNase purchased overseas by the patients' guardians had already been administered when we obtained informed consent from the guardians. In all patients, fibrinogen and/or anti-thrombin III levels were decreased, but thrombosis did not develop. There was only one mild adverse event (grade 2 urticaria) in one patient, in whom Erw-ASNase could be continued after increasing the doses of premedication with antihistamine and prednisolone. Erw-ASNase could be safely administered to all patients.