Purpose: Renal tumors account for approximately 7% of all childhood cancers. These include Wilms tumor (WT), clear cell sarcoma of the kidney (CCSK), malignant rhabdoid tumor of the kidney (MRTK), renal cell carcinoma (RCC), congenital mesoblastic nephroma (CMN) and other rare tumors. We investigated the epidemiology of pediatric renal tumors in Korea. Materials and Methods: From January 2001 to December 2015, data of pediatric patients (0–18 years) newly-diagnosed with renal tumors at 26 hospitals were retrospectively analyzed. Results: Among 439 patients (male, 240), the most common tumor was WT (n=342, 77.9%), followed by RCC (n=36, 8.2%), CCSK (n=24, 5.5%), MRTK (n=16, 3.6%), CMN (n=12, 2.7%), and others (n=9, 2.1%). Median age at diagnosis was 27.1 months (range 0-225.5) and median follow-up duration was 88.5 months (range 0-211.6). Overall, 32 patients died, of whom 17, 11, 1, and 3 died of relapse, progressive disease, second malignant neoplasm, and treatment-related mortality. Five-year overall survival and event free survival were 97.2% and 84.8% in WT, 90.6% and 82.1% in RCC, 81.1% and 63.6% in CCSK, 60.3% and 56.2% in MRTK, and 100% and 91.7% in CMN, respectively (p < 0.001). Conclusion The pediatric renal tumor types in Korea are similar to those previously reported in other countries. WT accounted for a large proportion and survival was excellent. Non-Wilms renal tumors included a variety of tumors and showed inferior outcome, especially MRTK. Further efforts are necessary to optimize the treatment and analyze the genetic characteristics of pediatric renal tumors in Korea.

Background: Hematologic malignancies have a relatively lower prevalence than major solid cancers, although the incidence of hematologic malignancies has significantly increased in recent years. However, understanding the current status of hematologic malignancy is significantly challenging because basic data regarding this malignancy are insufficient in the Korean population. Methods: From 2005 to 2015, the status of seven codes of hematologic malignancy, containing 24 subcodes defined using a classification defined by the Korean Classification of Disease-6, was analyzed. The number of new patients, crude incidence rate, prevalence rate, and age-standardized incidence rate were also investigated. Results were analyzed based on National Health Insurance Service (NHIS) data. Results: The number of new patients showed an overall increase over time and a rate of increase up to 56.7% for 10 years. The number of male patients was higher than that of female patients, with the majority of patients aged greater than 60 years. The incidence and prevalence rates have increased steadily. Conclusions Consistent with the previous studies, this study might be useful to understand the current status of hematologic malignancy and might contribute to the improvement of national public healthcare.

The histiocytosis is rare disorder characterized by the accumulation of macrophages, dendritic cells, or monocyte-derived cells in various tissues and organs of children and adults. Classifying histiocytic disorders is difficult and has changed over time as an understanding of the biology of these cells has evolved. The most recently revised 2016 WHO classification of histiocytosis and neoplasms of the macrophagedendritic cell lineages has proposed grouping this diverse group of over 100 clinical entities into five main groups based on clinical, histologic, and molecular relevance. Comprehensive genomic studies for histiocytosis have been described and our understanding of the pathogenesis and biology has increased over the past decade. These advances will be able to make precision medicine and targeted therapy possible in patients with histiocytosis. Among the histiocytosis, this review mainly focuses on the updated diagnosis and treatment of Langerhans cell histiocytosis (LCH) and hemophagocytic lymphohistiocytosis (HLH) in children.

Background: Except for data in the Korea Hemophilia Foundation Registry, little is known of the epidemiology of congenital bleeding disorders in Korea. Methods: Data were obtained from the Korean Health Insurance Review and Assessment Service (HIRA) database. Results: From 2010 to 2015, there were 2,029 patients with congenital bleeding disorders in the Korean HIRA database: 38% (n = 775) of these patients had hemophilia A (HA), 25% (n = 517) had von Willebrand disease (vWD), 7% (n = 132) had hemophilia B (HB), and 25% (n = 513) had less common factor deficiencies. The estimated age-standardized incidence rate (ASR) of HA and HB was 1.78–3.15/100,000 and 0.31–0.51/100,000, respectively. That of vWD was 1.38–1.95/100,000. The estimated ASR of HA showed increase over time though the number of new patients did not increase. Most patients with congenital bleeding disorders were younger than 19 years old (47.8%), and most were registered in Gyeonggi (22.1%) and Seoul (19.2%). Conclusion This is the first nationwide population-based study of congenital bleeding disorders in Korea. This study provides data that will enable more accurate estimations of patients with vWD. This information will help advance the comprehensive care of congenital bleeding disorders. We need to continue to obtain more detailed information on patients to improve the management of these diseases.

PURPOSE: Dexrazoxane has been used as an effective cardioprotector against anthracycline cardiotoxicity. This study intended to analyze cardioprotective efficacy and secondary malignancy development, and elucidate risk factors for secondary malignancies in dexrazoxane-treated pediatric patients. MATERIALS AND METHODS: Data was collected from 15 hospitals in Korea. Patients who received any anthracyclines, and completed treatment without stem cell transplantation were included. For efficacy evaluation, the incidence of cardiac events and cardiac event-free survival rates were compared. Data about risk factors of secondary malignancies were collected. RESULTS: Data of total 1,453 cases were analyzed; dexrazoxane with every anthracyclines group (D group, 1,035 patients) and no dexrazoxane group (non-D group, 418 patients). Incidence of the reported cardiac events was not statistically different between two groups; however, the cardiac event-free survival rate of patients with more than 400 mg/m2 of anthracyclines was significantly higher in D group (91.2% vs. 80.1%, p=0.04). The 6-year cumulative incidence of secondary malignancy was not different between both groups after considering follow-up duration difference (non-D, 0.52%±0.37%; D, 0.60%±0.28%; p=0.55). The most influential risk factor for secondary malignancy was the duration of anthracycline administration according to multivariate analysis. CONCLUSION: Dexrazoxane had an efficacy in lowering cardiac event-free survival rates in patients with higher cumulative anthracyclines. As a result of multivariate analysis for assessing risk factors of secondary malignancy, the occurrence of secondary malignancy was not related to dexrazoxane administration.
Anthracyclines ; Cardiotoxicity ; Dexrazoxane ; Disease-Free Survival ; Follow-Up Studies ; Humans ; Incidence ; Korea ; Multivariate Analysis ; Neoplasms, Second Primary ; Risk Factors* ; Stem Cell Transplantation

BACKGROUND: Previous studies have recommended a 2- to 5-year waiting time prior to kidney transplantation (KT) in patients with end-stage renal disease (ESRD) and symptomatic renal cell carcinoma (RCC) and no delay for incidental early-stage RCC. Data on Asian KT recipients are unavailable.METHODS: This is a Korean single-center retrospective study on 35 KT recipients with ESRD and RCC. Patients were classified into two groups: early KT (KT performed within 1 year after nephrectomy for RCC, including KT with simultaneous nephrectomy) and delayed KT (KT performed over than 1 year after nephrectomy for RCC). Patient survival, graft survival, and cancer recurrence were compared between both groups.RESULTS: There were no statistically significant differences in patient survival (P = 0.388), graft survival (P = 0.317), or graft rejection rate (P = 0.207) between the early and delayed KT groups. Additionally, there were no differences in pathological characteristics or RCC stage other than cancer histology: acquired cystic disease-associated RCC (47.4%) was the most common RCC type in the early KT group, whereas clear cell type (62.5%) was the most common RCC type in the delayed KT group. No RCC recurrence was observed.CONCLUSION: Patients with early-stage and asymptomatic RCC do not require a mandatory observational period prior to KT after curative nephrectomy
Asian Continental Ancestry Group ; Carcinoma, Renal Cell ; Graft Rejection ; Graft Survival ; Humans ; Kidney Failure, Chronic ; Kidney Transplantation ; Kidney ; Nephrectomy ; Recurrence ; Retrospective Studies ; Transplant Recipients

BACKGROUND: Neutropenia can be easily found in previously healthy children associated with various medical conditions, and the clinical course ranges from transient benign to life threatening. This study aimed to investigate the etiology, clinical characteristics, and clinical courses of neutropenia in previously healthy children. METHODS: We evaluated 215 previously healthy children under aged 18 years who diagnosed with neutropenia in two hospitals. Clinical and laboratory features were analyzed retrospectively based on the medical records. RESULTS: Transient infectious neutropenia (TIN) accounted for 97.7% of cases and chronic neutropenia (CN), for 2.3%. An infectious agent was identified in 128/210 (61%) patients with TIN, and the most frequent agents were viruses (46.5%). The most common viral agent was respiratory syncytial virus (RSV) (29%). TIN subgroups exhibited no differences in severity according to infectious agent (virus, bacteria, Mycoplasma); however, neutropenia severity differed among viral agents [mild-to-moderate neutropenia in the RSV group (857.3±293.3/µL) and moderate-to-severe neutropenia in the parainfluenza group (567.3±198.1/µL); P=0.017]. All patients with CN had anti-neutrophil antibody positivity (autoimmune neutropenia, AIN), and moderate-to-severe neutropenia predominated. The median duration of TIN was 8 days (range, 3–286 days), and it was significantly longer for AIN at 330 days (range, 217–730 days) (P=0.000). The median duration of neutropenia was also different according to each viral agent, with 4 days (range, 3–11 days) for the RSV group and longer durations for 3 other groups (influenza, parainfluenza, other respiratory viruses) (P=0.015). CONCLUSION: Neutropenia in previously healthy children is usually of transient infectious origin, with mild-to-moderate severity, and it resolves spontaneously without complications.
Autoimmune Diseases ; Bacteria ; Child* ; Humans ; Medical Records ; Neutropenia* ; Paramyxoviridae Infections ; Respiratory Syncytial Viruses ; Retrospective Studies ; Tin

Spinal epidural hematoma (SEH) is a rare neurosurgical emergency in which pressure on the spinal cord leads to acute neurological deficits, and is a rare complication in children with hemophilia. We report three cases of SEH in severe hemophilia A. An 8-month-old boy who presented with non-traumatic acute-onset irritability was found to have SEH and was later diagnosed with hemophilia. The two other patients presented with neck pain and magnetic resonance imaging confirmed the diagnosis of SEH. Two patients who received conservative management fully recovered, however the patient who presented with progressive neurological abnormalities at the time of diagnosis, received surgery but later developed breathing difficulties and quadriplegia. Early diagnosis and immediate, aggressive, clotting factor replacement therapy are crucial when managing SEH in children with hemophilia. Immediate and aggressive factor replacement, accompanied by both neurological monitoring and early imaging, are essential for hemophiliac with suspected SEH.
Child* ; Diagnosis ; Early Diagnosis ; Emergencies ; Hematoma ; Hematoma, Epidural, Spinal* ; Hemophilia A* ; Humans ; Infant ; Magnetic Resonance Imaging ; Male ; Neck Pain ; Quadriplegia ; Respiration ; Spinal Cord

Spontaneous intra-abdominal hemorrhages are uncommon in hemophilic patients. They can cause complications in patients with severe hemophilia, and are associated with a high mortality rate. To date, there is no guideline for the management of intra-abdominal hemorrhage in patients with hemophilia. Management of intra-abdominal hemorrhage ranges from conservative treatment to emergent embolization or surgery. We describe two children with hemophilia A, who were successfully treated non-operatively by administering coagulation factor concentrates and embolization, and were later discharged from the hospital. We emphasize the role of an active approach in the evaluation and management of intra-abdominal hemorrhage without any surgical intervention.
Blood Coagulation Factors ; Child ; Hemophilia A ; Hemorrhage ; Humans ; Mortality

In Korea, recent epidemiologic studies show that the incidence of β-thalassemia is increasing as the influx of South-East Asian population increases and molecular technologies develop. However, many patients are still misdiagnosed as iron deficiency anemia (IDA). All patients with microcytic anemia need to perform evaluation including reticulocyte index, Mentzer index, and iron studies. Considering the increasing incidence of β-thalassemia, hemoglobin beta globulin (HBB) gene sequencing should be performed if suspicious. In our cases, patients whose parents were both Koreans were confirmed to have β-thalassemia with a substitution in c1, ATG>GTG, and deletion of the HBB gene. In Korea, initiation condon ATG>AGG (20.9%) is most common mutation, followed by codon 17 (A>T) (17.6%), codon 121 (G>T) (12.1%), and so on. We report two cases of β-thalassemia diagnosed by genetic testing for microcytic anemia.
Anemia ; Anemia, Iron-Deficiency ; Asian Continental Ancestry Group ; Beta-Globulins ; beta-Thalassemia ; Codon ; Epidemiologic Studies ; Genetic Testing ; Humans ; Incidence ; Iron ; Korea ; Parents ; Reticulocytes