We reviewed the clinical courses of nine patients in our institute with acquired bone marrow failure syndrome. Five male and four female patients with a median age of 7 years (range: 6–19 years) were included in this study. Four patients were diagnosed with aplastic anemia, four with refractory cytopenia of childhood, and one with refractory cytopenia with multilineage dysplasia. Five patients were treated with immunosuppressive therapy (IST), including anti-thymocyte globulin and cyclosporine. IST responses were observed in only one patient with RCC (partial response). Nine patients received bone marrow transplantation (BMT) following fludarabine-containing regimen for conditioning. Engraftment was successful for all patients, although one patient received a second BMT owing to the development of a donor-type bone marrow aplasia. Acute graft-versus-host disease (GVHD) grade II or higher developed in five patients. Chronic GVHD developed in two patients, one of whom developed an extensive type. In terms of transplantation-associated complications, severe thrombotic microangiopathy, myasthenia gravis, or brain tumor developed in each patient. The IST response rate in our small cohort was lower than that in previous reports; however, all patients recovered from bone marrow failure after treatment by BMT. The development of GVHD and sequelae associated with BMT affected the patients’ quality of life.

Central venous catheters (CVCs) have improved the safety of chemotherapy for malignant diseases, but complications include catheter infection, thrombophlebitis and fluid extravasation. We describe two patients with childhood acute leukemia and massive fluid extravasation that occurred during CVC management and who developed sudden chest pain and breathing difficulties. The CVCs were inserted at the left upper arm in both patients and problems occurred within one month thereafter. Contrast-imaging findings confirmed the absence of direct communication between the CVC tip and the pleural cavity in both patients, implying that massive bleeding was unlikely to occur after CVC removal. Identifying the precise location of the CVC tip by contrast radiography allowed for the selection of an appropriate treatment strategy for patients with CVC-related complications such as fluid extravasation.

Neuroblastoma in children over 18 months of age is usually advanced when detected and primary resection is not feasible. We experienced treating an 18-month-old boy with a huge right adrenal mass presenting as an intraabdominal hemorrhage. He developed hemorrhagic shock and underwent arterial embolization as a life-preserving therapy. The embolization was temporarily effective in stabilizing the patient’s circulatory condition. The patient underwent primary resection of the tumor after three embolizations in order to control recurrent bleeding, followed by full-dose chemotherapy and radiotherapy. The patient has been free from disease for 4 years after the treatments. Bleeding from neuroblastoma should be recognized as an oncologic emergency. The arterial embolization of pediatric tumors, which is uncommon in children, proved to be an effective option for controlling life-threatening hemorrhage.

A 3-year-old boy with no medical history presented with fever and dyspnea to his previous physician. Computed tomography demonstrated a posterior mediastinal tumor, an osteolytic lesion on the left 8^th rib, and marked pleural thickening and pleural effusion in the left thoracic cavity. These imaging findings strongly suggested a primary bone neoplasm. A soft tissue neoplasm such as Askin tumor was suspected, and chemotherapy was begun. However, the pathological report of the tumor biopsy revealed poorly differentiated neuroblastoma. No distant metastasis was apparent. The mitosis-karyorrhexis index was low, and no MYCN amplification was detected. The tumor was assessed to be at stage 3 on the basis of the International Neuroblastoma Staging System, and the patient was considered to be at high risk. After chemotherapy following the JNBSG protocol, he underwent surgical resection of the mediastinal tumor. The tumor beds were subjected to proton beam therapy, followed by high-dose chemotherapy with autologous peripheral blood stem cell transplantation. The patient was further treated with retinoic acid, and has presented no sign of recurrence 2 years after the completion of therapy.

We report on the case of an 11-month-old girl with postoperative intussusception after tumor resection for nephroblastoma. The patient had a distended abdomen, bilious emesis and increased nasogastric output since 2 days after the surgery. A second surgery was performed 7 days after the initial surgery because of suspected adhesive obstruction of the intestine. Intussusception was the diagnosis. A patient with postoperative intussusception, a rare complication, presents with bilious vomiting, increased nasogastric output, and abdominal distention without an abdominal mass or bloody stool. Radiological examinations, including ultrasonography are less informative for making a diagnosis. In most cases, these symptoms occur within a few weeks after surgery, and clinical symptoms resemble the adverse effects of postoperative chemotherapy or radiotherapy. These clinical characteristics make diagnosis difficult. Postoperative intussusception should be suspected in patients with prolonged bilious vomiting soon after retroperitoneal surgery.

Inflammatory myofibroblastic tumor (IMT) is considered to be a neoplasm on the basis of the clonal rearrangement of the ALK gene in half of all patients. However, when ALK rearrangement is negative, it is difficult to distinguish IMT from inflammatory pseudotumor (IPT) owing to their similar pathological features. We encountered a 7-year-old boy who developed left facial and abducens nerve palsy. Diagnostic imaging revealed a mass lesion in the left masticatory space. HE and immunological staining of a tumor biopsy specimen showed the proliferation of spindle cells and the infiltration of inflammatory cells that were ALK negative. ALK rearrangement was undetectable in in situ hybridization. Karyotypic analysis of the biopsy sample showed the chromosomal translocation of t(1;11)(q32;q23) in 5 of 20 mitoses, leading to the diagnosis of IMT. The patient was treated with chemotherapy including cyclophosphamide, vincristine, pirarubicin and cisplatin, and the tumor effectively regressed thereafter. No recurrence has been observed 3 and a half years after the completion of chemotherapy. In this patient, we showed the usefulness of the karyotypic analysis of a tumor specimen to distinguish IMT from IPT, and revealed t(1;11)(q32;q23) to be a potential chromosomal translocation involved in the pathogenesis of IMT.

Dermatofibrosarcoma protuberans (DFSP) is a rare disease in infants and is classified as an intermediate-grade malignancy. The characteristics of the tumor are limited metastasis, slow local but aggressive growth, tendency to recur locally, and rarely a depressed lesion. We report on the case of a 12-year-old boy who developed DFSP on his left chest at five years of age. The patient was suspected to have angioma or lymphangioma and has been followed up at the outpatient clinic in our hospital. Over a period of seven years, the tumor increased in size and showed both protuberant lesions and depressed lesions. We suspected malignant soft tissue tumor, such as sarcoma, on the basis of ultrasonography and magnetic resonance imaging (MRI) findings. The tumor was excised, and its histopathological analysis indicated benign tumor with spindle cells. However, the permanent specimen demonstrated DFSP. We then excised the residual tumor including a wider margin. We found a rare type of DFSP with a depressed epidermis. The boy was surgically treated. DFSP did not recur nor metastasize in the two years of follow up.

Myeloid sarcoma is a rare extramedullary disease associated with acute myeloid leukemia (AML). We present the case of a 5-year-old boy with myeloid sarcoma followed by acute myeloid leukemia (AML M0). He was admitted to a local hospital because of recurrent vomiting, abdominal pain, and fever. Abdominal CT disclosed swelling of multiple lymph nodes in the abdomen and ileus. The patient was referred to our hospital for further diagnosis and treatment. Oral antibiotics and intravenous hydration were administered for suspected infectious mesenteric lymphadenitis. After the symptoms subsided, the patient was discharged. However, mesenteric lymphadenopathy remained unchanged and the serum-soluble IL-2R level gradually increased. Blastic cells appeared in the peripheral blood two months after the discharge; thus, we performed bone marrow aspiration and laparoscopic mesenteric lymph node biopsy. Tumor cells were positive for the phenotype of myeloid lineage but negative for MPO, indicating myeloid sarcoma caused by acute myeloid leukemia (AML M0). Myeloid sarcoma in mesenteric lymph nodes followed by AML M0 is very rare, but important in the differential diagnosis of mesenteric lymphadenopathy.

We report a pediatric case of B-cell precursor acute lymphoblastic leukemia with hyperkalemia and ventricular tachycardia (VT) caused by spontaneous tumor lysis syndrome. A 10-year-old girl was brought to our hospital by ambulance because of generalized clonic seizure and pallor. On arrival, her blood pressure was too low to measure. Her laboratory findings were as follows: WBC count, 30,830/μL (blast 91%); RBC count, 149×10⁴/μL; Hb level, 4.5 g/dL; Ht, 13.3%; Plt count, 1.0×10⁴/μL; LD level, 4,125 IU/L; uric acid level, 46.1 mg/dL; urea level, 85 mg/dL; Cr level, 1.85 mg/dL; K level, 9.7 mEq/L; Ca level, 5.8 mg/dL; and P, 26.3 mg/dL. ECG showed ventricular tachycardia. Two and a half hours later, hemodialysis was started; then arrhythmia immediately disappeared and her blood pressure normalized. Flow cytometry of the peripheral blood blasts confirmed the presence of cells positive for CD10, CD19, and HLA-DR, which is the characteristic immunophenotype of B-cell precursor acute lymphoblastic leukemia.

Acral erythema (AE), also known as palmar-plantar erythrodysesthesia syndrome, is a painful and edematous reddening of the palms and soles, which often emerges as an adverse effect of high-dose chemotherapy. A 2-year-old girl exhibited multiple bullous and erythematous lesions with pain and numbness in her palms and soles after high-dose methotrexate (MTX) treatment for acute lymphoblastic leukemia. The same lesions reemerged by repeating either high- or intermediate-dose MTX therapy. Direct deposition of MTX in the eccrine gland and its cytotoxic effects were considered as the mechanisms of AE pathogenesis since the severity of AE correlated with the MTX dose. However, allergic reactions may also contribute to the pathogenesis because the lymphocyte stimulation test showed a positive reaction to MTX. The lesions were successfully treated with topical and systemic corticosteroid therapy. Chemotherapy-induced AE does not affect the prognosis of the underlying disease; therefore, it is not necessary to alter the subsequent chemotherapy.

Systemic Epstein-Barr virus (EBV)-positive T-cell lymphoproliferative disease (TLPD) in childhood is rare and presents with heterogeneous clinical features; however, most cases exhibit an aggressive clinical course and a poor prognosis without allogenic stem cell transplantation. Here, we report an atypical clinical course of TLPD in the central nervous system of a patient with well-controlled EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH), who was treated by only surgical resection and maintained in complete remission (CR). A 5-year-old girl was diagnosed as having EBV-HLH and achieved disease control with prednisolone, cyclosporine, and combination chemotherapy. Three months after discharge, follow-up MRI of posterior reversible encephalopathy syndrome (PRES) that occurred while treating EBV-HLH revealed a mass lesion, measuring 3×3×2 cm³, in the left frontal lobe and diffuse white-matter edema, although she showed no neurological symptoms. The mass was completely removed by surgery. The tissue revealed apparent infiltration of monotonous lymphocytes expressing CD3 and CD8. An early RNA test showed positivity for EBV. The pathological features were concordant with systemic EBV-positive TLPD. Because PCR analysis revealed positivity for EBV-but a low viral load, we decided against chemotherapy. Moreover, since surgery, she has remained in CR for approximately 3 years without chemotherapy. The clinical features and course of TLPD are highly heterogeneous. To establish the classification criteria and standard treatment for TLPD and other overlapping diseases, further acquisition of cases, particularly in Japan, is required.