Successful treatment of congenital systemic juvenile xanthogranulomatosis with pulmonary involvement.

Juvenile xanthogranuloma (JXG) is a common form of non-Langerhans cell histiocytosis, which usually presents with spontaneously regressing skin lesions. Systemic involvement is rare and mostly seen in patients with multiple skin nodules. It can spontaneously regress, but sometimes systemic involvement can cause life-threatening symptoms and can be fatal. Herein, we report a case of congenital systemic JXG with multiple skin nodules, soft tissue and pulmonary involvement. She was successfully treated with chemotherapy according to Langerhans cell histiocytosis treatment protocol IV of the Histiocyte Society (LCH-IV).

Outcome of autologous hematopoietic stem cell transplantation in children and adolescents with relapsed or refractory Hodgkin's lymphoma.

This study evaluates the outcome of 66 pediatric patients with rrHL who underwent autoHSCT. Twenty-nine patients experienced early relapse, and 19 patients experienced late relapse. Of 18 newly diagnosed with HL, 13 were primary refractory disease and five had late responsive disease. At the time of transplantation, only 68% of the patients were chemosensitive. The majority of patients received BCNU + etoposide + ara-C + melphalan for conditioning (45/66), and peripheral blood (56/66) was used as a source of stem cells. After a median follow-up period of 39 months, 46 patients were alive. At five yr, the probabilities of OS, EFS, the relapse rate, and the non-relapse mortality rate were 63.1%, 54.3%, 36.4%, and 9.1%, respectively. The probability of EFS in chemosensitive and chemoresistant patients at five yr was 72.3% and 19%, respectively (p < 0.001). Multivariate analysis showed that chemoresistant disease at the time of transplantation was the only factor predicting limited both OS (hazard ratio = 4.073) and EFS (hazard ratio = 4.599). AutoHSCT plays an important role for the treatment of rrHL in children and adolescents, and survival rates are better for patients with chemosensitive disease at the time of transplantation.

Successful haematopoietic stem cell transplantation in 44 children from healthy siblings conceived after preimplantation HLA matching.

Haematopoietic stem cell transplantation (HSCT) remains the best therapeutic option for many acquired and inherited paediatric haematological disorders. Unfortunately, the probability of finding an HLA matched donor is limited. An alternative technique is PGD combined with HLA matching, which offers the possibility of selecting unaffected embryos that are HLA compatible with the sick child, with the aim of possible use of stem cells from the resulting baby in future. Since the first successful report for Fanconi anaemia a decade ago, the therapeutic success of this technique was reported in a few cases and for a limited number of disorders. Here, we report full recovery of 44 sick children who received HSCT from healthy infants conceived after pre-implantation HLA matching for the following 10 indications; beta-thalassaemia, Wiskott-Aldrich syndrome, Fanconi anaemia, sickle cell anaemia, acute myeloid leukaemia, acute lymphoblastic leukaemia, Glanzmann's thrombasthaenia, Diamond-Blackfan anaemia, X-linked adrenoleukodystrophy and mucopolysaccharidosis type I. No serious complications were observed among recipients and donors. Graft failure occurred in four children with beta-thalassaemia where a second HSCT was planned. Preimplantation HLA matching is a reliable technique and provides a realistic option for couples seeking treatment for an affected child when no HLA-matched donor is available.

Central nervous system involvement of epstein barr virus associated lymphoproliferative disorder in a child with acute lymphoblastic leukemia: successful treatment with rituximab and interferon-alpha.

UNLABELLED: Central nervous system (CNS) involvement of Epstein-Barr virus (EBV)-associated lymphoproliferative disease is a rare and serious complication in children with leukemia. Although rituximab therapy seems to be promising in these cases, persistent hypogammaglobulinemia may appear after treatment due to complete depletion of normal B lymphocytes in the peripheral blood. Here we report isolated CNS involvement of EBV-associated lymphoproliferative disorder in a 4-year-old boy with acute leukemia. The patient was treated with rituximab and interferon alpha; however, persistent hypogammaglobulinemia developed as a complication. Given the rarity of the complication in children receiving these agents, our experience with such a case may be helpful to others. CONFLICT OF INTEREST: None declared.

HLA-matched family hematopoetic stem cell transplantation in children with beta thalassemia major: the experience of the Turkish Pediatric Bone Marrow Transplantation Group.

From January 1991 to June 2009, 245 children with beta thalassemia major who underwent their first allogeneic HSCT in Turkey and who were followed for a minimum of one yr post-transplantation were enrolled this study. The median age of the patients was 6.6 yr old (range, 1-22 yr). The distribution of Pesaro risk class I, II, and III categories was 41, 130, and 63 children, respectively. The median serum ferritin level was 2203 ng/mL. Eighty-eight patients received bone marrow (BM) stem cells; 137, peripheral blood (PB) stem cells; and 20, cord blood (CB) stem cells. The donors were HLA-matched siblings or parents. Median engraftment times were shorter in PBSCT patients compared with the BMT group (p < 0.001). Grade II-IV acute GvHD was observed in 33 children (13.5%), while cGvHD was observed in 28 patients (12.5%), eight of whom had the extensive form. Thalassemic reconstitution was observed in 43 (17%) of the transplant patients. Post-transplant aplasia occurred in three patients, and the TRM rate was 7.75%. Seventeen patients were lost after 100 days. The thalassemia-free survival and OS rates were 68% (95% CI, 61.8-74.2) and 85.0% (95% CI, 80.2-89.8), respectively. We believe that this study is important because it is the first multicenter national data for children with beta thalassemia major receiving HSCT.

Thalassemia-free and graft-versus-host-free survival: outcomes of hematopoietic stem cell transplantation for thalassemia major, Turkish experience.

We report the national data on the outcomes of hematopoietic stem cell transplantation (HSCT) for thalassemia major (TM) patients in Turkey on behalf of the Turkish Pediatric Stem Cell Transplantation Group. We retrospectively enrolled 1469 patients with TM who underwent their first HSCT between 1988 and 2020 in 25 pediatric centers in Turkey. The median follow-up duration and transplant ages were 62 months and 7 years, respectively; 113 patients had chronic graft versus host disease (cGVHD) and the cGVHD rate was 8.3% in surviving patients. Upon the last visit, 30 patients still had cGvHD (2.2%). The 5-year overall survival (OS), thalassemia-free survival (TFS) and thalassemia-GVHD-free survival (TGFS) rates were 92.3%, 82.1%, and 80.8%, respectively. cGVHD incidence was significantly lower in the mixed chimerism (MC) group compared to the complete chimerism (CC) group (p < 0.001). In survival analysis, OS, TFS, and TGFS rates were significantly higher for transplants after 2010. TFS and TGFS rates were better for patients under 7 years and at centers that had performed over 100 thalassemia transplants. Transplants from matched unrelated donors had significantly higher TFS rates. We recommend HSCT before 7 years old in thalassemia patients who have a matched donor for improved outcomes.

Variant clinical courses in children with immune thrombocytopenic purpura: Sixteen year experience of a single medical center.

OBJECTIVE: Immune thrombocytopenic purpura (ITP) is the most common cause of acquired thrombocytopenia in children. The objective of this study was to evaluate the presenting features, variation in the clinical courses, initial response rate to therapy, and long-term outcome in patients with ITP. METHODS: Three hundred and fifty out of 491 newly diagnosed patients with ITP between the initial diagnosis ages of 6 months to 16 years were included in this retrospective, descriptive study. Patients with acute vs chronic ITP, acute vs recurrent ITP and chronic vs recurrent ITP were compared in terms of age at diagnosis, gender, initial platelet count, response rate to initial therapy, long-term outcome, and total duration of follow-up. RESULTS: The clinical courses of the patients were determined as acute, chronic and recurrent in 63.8%, 29.1%, and 7.1%, respectively. Platelet count >20x109/L and initial diagnosis age >10 years were found to increase the probability of chronic outcome by at least two-fold. CONCLUSION: It is concluded that ITP in childhood is a common disease with low morbidity and mortality. In addition to the acute and chronic form, a rare recurrent form, which accounts for about 4-7% of all ITP patients, should be considered.

Atypical teratoid/rhabdoid tumor of the central nervous system: clinicopathologic and immunohistochemical features of four cases.

BACKGROUND: Atypical teratoid/rhabdoid tumor (AT/RT) is a rare aggressive infantile neoplasm of uncertain origin. This study was performed to assess the clinicopathologic and immunohistochemical features of four AT/RT cases. CASE REPORTS: Two cases were male and two were female, and their ages ranged from 8 to 103 months. Tumors were located in the cerebellum (two cases), frontoparietal lobe (one case), and third ventricle (one case). Histopathologically, the tumors were composed of rhabdoid cells and undifferentiated small cells mixed with epithelial or mesenchymal components. However, one of the tumors was composed predominantly of a mesenchymal component mimicking a sarcoma. Immunohistochemically, vimentin (4/4), epithelial membrane antigen (4/4), cytokeratin (3/4), smooth muscle actin (4/4), glial fibrillary acidic protein (4/4), S-100 (4/4), and synaptophysin (1/4) were positive in varying proportions, while desmin and INI-1 were negative in all the cases. All of the patients died within a mean of 14 months due to tumor progression despite the chemotherapy. Only one of our patients lived for 40 months after the diagnosis. In conclusion, AT/RTs are aggressive tumors. They can occur in a variety of locations, such as the third ventricle. Morphologically, a large spectrum can be seen, like predominantly sarcoma in appearance, but immunohistochemistry is helpful in the correct diagnosis.

Radiological nodule behavior: A critical parameter in the surgical management of pediatric pulmonary metastases.

Divarci E, Arslan S, Dökümcü Z, Kantar M, Demirag B, Öniz H, Ertan Y, Alper H, Erdener A, Özcan C. Radiological nodule behavior: A critical parameter in the surgical management of pediatric pulmonary metastases. Turk J Pediatr 2018; 60: 372-379. Radiological nodule behavior (RNB) means the course of nodule appearance on consecutive CT scans. In this study, we aimed to discuss the effects of RNB on prognosis of patients with pulmonary metastasis. Retrospective analysis of patients who underwent pulmonary metastasectomy (PM) between 2005-2015 was performed. RNBs were grouped as stable, enlarging or new rising nodules. The effects of RNBs were analyzed on recurrence, 1- and 3-year event free survival (EFS) and mortality. Twenty-seven patients (18 male) underwent PM with a median age of 15 years (3-18 years). The diagnoses were listed as osteosarcoma (13), Wilms` tumor (7), Ewing`s sarcoma (3), synovial sarcoma (2), rabdomyosarcoma (1) and mixed germ cell tumor of testis (1). RNBs were new rising in 15 patients (55%), enlarging in seven patients (26%) and stable in five patients (19%). Vital tumor metastasis was detected in all of the patients with enlarging nodules (100%); in 10 of the 15 patients with new rising nodules (66%) and none of the patients with stable nodules. None of the patients with stable nodules developed recurrence or died after PM (p˂0.05). In patients with enlarging nodules, metastases recurred and they died in the postoperative period. These findings were similar in different types of tumors. RNB could be used as a critical parameter in deciding surgical management strategies of pulmonary metastases. Stabile nodules should be observed by close follow-up with serial CT scans without surgery. All of the suspected new rising nodules should undergo surgical sampling to avoid unnecessary chemotherapy. Nodule progression under chemotherapy is a poor prognostic criteria for overall survival.

Risk factors predicting the survival of pediatric patients with relapsed/refractory non-Hodgkin lymphoma who underwent hematopoietic stem cell transplantation: a retrospective study from the Turkish pediatric bone marrow transplantation registry.

We examined outcomes of 62 pediatric patients with relapsed or refractory non-Hodgkin lymphoma (rr-NHL) who underwent hematopoietic stem cell transplantation (HSCT). The overall survival (OS) and event-free survival (EFS) rates were 65% and 48%, respectively. Survival rates for patients with chemosensitive disease at the time of HSCT were significantly higher than those of patients with chemoresistant disease (69% vs. 37%, p = .019 for OS; 54% vs. 12%, p < .001 for EFS; respectively). A chemoresistant disease at transplantation was the only factor that predicted a limited OS (hazard ratio = 10.00) and EFS (hazard ratio = 16.39) rates. Intensive chemotherapy followed by HSCT could be an effective strategy for treating children with rr-NHL and may offer improved survival for a significant group of pediatric patients, particularly those with chemosensitive disease at transplantation.

Juvenile Myelomonocytic Leukemia in Turkey: A Retrospective Analysis of Sixty-five Patients.

OBJECTIVE: This study aimed to define the status of juvenile myelomonocytic leukemia (JMML) patients in Turkey in terms of time of diagnosis, clinical characteristics, mutational studies, clinical course, and treatment strategies. MATERIALS AND METHODS: Data including clinical and laboratory characteristics and treatment strategies of JMML patients were collected retrospectively from pediatric hematology-oncology centers in Turkey. RESULTS: Sixty-five children with JMML diagnosed between 2002 and 2016 in 18 institutions throughout Turkey were enrolled in the study. The median age at diagnosis was 17 months (min-max: 2-117 months). Splenomegaly was present in 92% of patients at the time of diagnosis. The median white blood cell, monocyte, and platelet counts were 32.9x109/L, 5.4x109/L, and 58.3x109/L, respectively. Monosomy 7 was present in 18% of patients. JMML mutational analysis was performed in 32 of 65 patients (49%) and PTPN11 was the most common mutation. Hematopoietic stem cell transplantation (HSCT) could only be performed in 28 patients (44%), the majority being after the year 2012. The most frequent reason for not performing HSCT was the inability to find a suitable donor. The median time from diagnosis to HSCT was 9 months (min-max: 2-63 months). The 5-year cumulative survival rate was 33% and median estimated survival time was 30±17.4 months (95% CI: 0-64.1) for all patients. Survival time was significantly better in the HSCT group (log-rank p=0.019). Older age at diagnosis (>2 years), platelet count of less than 40x109/L, and PTPN11 mutation were the factors significantly associated with shorter survival time. CONCLUSION: Although there has recently been improvement in terms of definitive diagnosis and HSCT in JMML patients, the overall results are not satisfactory and it is necessary to put more effort into this issue in Turkey.

Pancreatoblastoma, a Rare Childhood Tumor: A Case Report.

Pancreatoblastoma, rarely encountered in the literature, is a malignant exocrine tumor seen in the pancreas. A 5-year-old boy suffering from abdominal pain was sent to our institute for further examination and treatment. Clinical examination was normal but for a palpable abdominal tumor mass. Abdominal Doppler ultrasonography showed a mass with well-defined margins within the body of the pancreas. Laboratory tests, including lactic dehydrogenase, alpha-fetoprotein and cancer antigen 125 were abnormal. The tumor invading the splenic vein and transverse colon was removed totally. We observed a hypercellular tumor in histopathological examination. The tumor had epithelial acinar cells and squamoid morules (corpuscles) separated by stromal bands. Adjuvant chemotherapy was used after surgery. However, the patient died 14 months later. All data about pancreatoblastoma have to be collected in order to choose the treatment to elucidate the molecular pathogenesis of the tumor, to diagnose it early and to develop target-specific treatments.

Treatment of high-risk neuroblastoma: National protocol results of the Turkish Pediatric Oncology Group.

BACKGROUND: The national protocol aimed to improve the outcome of the high risk neuroblastoma patients by high-dose chemotherapy and stem cell rescue with intensive multimodal therapy. MATERIALS AND METHODS: After the 6 induction chemotherapy cycles, patients without disease progression were nonrandomly (by physicians' and/or parent's choices) allocated into two treatment arms, which were designed to continue the conventional chemotherapy (CCT), or myeloablative therapy with autologous stem cell rescue (ASCR). RESULTS: Fifty-six percent (272 patients) of patients was evaluated as high risk. Response rate to induction chemotherapy was 71%. Overall event-free survival (EFS) and overall survival (OS) at 5 years were 28% and 36%, respectively. "As treated" analysis documented postinduction EFS of 41% in CCT arm (n = 138) and 29% in ASCR group (n = 47) (P = 0.042); whereas, OS was 45% and 39%, respectively (P = 0.05). Thirty-one patients (11%) died of treatment-related complications. CONCLUSION: Survival rates of high-risk neuroblastoma have improved in Turkey. Myeloablative chemotherapy with ASCR has not augmented the therapeutic end point in our country's circumstances. The adequate supportive care and the higher patients' compliance are attained, the better survival rates might be obtained in high-risk neuroblastoma patients received myeloablative chemotherapy and ASCR.

Hyperleukocytosis in childhood acute lymphoblastic leukemia: complications and treatment outcome.

Hyperleukocytosis, defined as a peripheral leukocyte count ≥ 100x109/L, is seen in 5-20% of newly diagnosed cases of childhood leukemia and is a poor prognostic factor. In this study, we aimed to examine the presenting clinical and laboratory features, complications, and treatment outcome of 47 children with acute lymphoblastic leukemia (ALL) and hyperleukocytosis who were diagnosed and treated in four medical centers of Izmir between January 1990 and January 2001. The median age was 5.0 years (range: 0.1-16.3 years). Median white blood cell count was 495x109/L (range: 107x109/L- 794x109/L). Forty-two of 47 patients (90%) had hepatosplenomegaly, 5 (11%) had respiratory distress, 3 (6%) had neurologic symptoms, 3 (6%) had diffuse cervical lymphadenopathy, and 3 (6%) had acute renal failure at admission. Ten of 47 patients (21%) had central nervous system involvement, and 17 (36%) had mediastinal mass. Ten patients (21%) had coagulopathy and 15 patients (32%) had metabolic complications (8 patients had hyperuricemia, 4 had hyperphosphatemia, 2 had hyperuricemia, hyperphosphatemia and hypercalcemia, and 1 had hypocalcemia) before the initiation of therapy. Forty of 47 patients (85%) with hyperleukocytosis were effectively managed with intravenous hydration, alkalinization, and allopurinol therapy. Early death during remission induction therapy occurred in 5 patients (11%) with respiratory distress and sepsis. Kaplan-Meier estimates of event free survival and overall survival were 37.0% and 40.5%, respectively.

The role of radiotherapy in local control of nonextremity Ewing sarcomas.

PURPOSE: To evaluate the results of radiotherapy and the prognostic factors affecting local control in nonextremity Ewing sarcomas. METHODS: Between 1995 and 2011, 44 patients with nonextremity Ewing sarcomas were treated with radiotherapy. Tumor localizations were pelvis in 23, spine in 13, thoracic region in 5, and cranium in 3 patients. Tumor size was ≥8 cm in 56.8% of patients. Distant metastases were present in 19 of the patients at the time of diagnosis (43.1%). All patients were treated with 12 weeks of neoadjuvant chemotherapy followed by surgery and radiotherapy (45-54 Gy) or radiotherapy alone (54-64.8 Gy). Radiotherapy was applied due to microscopic residue (R1) in 5 patients after the operation and macroscopic tumor in 39 patients (macroscopic residue [R2] and nonresectable tumor). RESULTS: Median follow-up was 49 months (range 9-195). Local failures developed in 7 patients (15.9%) and local control at 5 years was 81.4%. Local recurrence was detected in 6 patients (6/38) who did not have residual tumor after RT. Progression was detected in 1 patient (1/6) who had residual tumor. All those patients with local failure experienced further distant metastases. Possible prognostic factors such as age (≤17 vs >17), tumor localization, tumor volume (≤8 cm vs >8 cm), and M status at diagnosis (0 vs 1) were not related to local control. CONCLUSIONS: Radiotherapy, either alone or adjuvant to surgery, provides local control in 80% of nonextremity Ewing sarcomas and plays an important role in treatment.

Prognostic Factors and a New Prognostic Index Model for Children and Adolescents with Hodgkin's Lymphoma Who Underwent Autologous Hematopoietic Stem Cell Transplantation: A Multicenter Study of the Turkish Pediatric Bone Marrow Transplantation Study Group.

OBJECTIVE: The prognostic factors and a new childhood prognostic index after autologous hematopoietic stem cell transplantation (AHSCT) in patients with relapsed/refractory Hodgkin's lymphoma (HL) were evaluated. MATERIALS AND METHODS: The prognostic factors of 61 patients who underwent AHSCT between January 1990 and December 2014 were evaluated. In addition, the Age-Adjusted International Prognostic Index and the Childhood International Prognostic Index (CIPI) were evaluated for their impact on prognosis. RESULTS: The median age of the 61 patients was 14.8 years (minimum-maximum: 5-20 years) at the time of AHSCT. There were single relapses in 28 patients, ≥2 relapses in eight patients, and refractory disease in 25 patients. The chemosensitivity/chemorefractory ratio was 36/25. No pretransplant radiotherapy, no remission at the time of transplantation, posttransplant white blood cell count over 10x103/µL, posttransplant positron emission tomography positivity at day 100, and serum albumin of <2.5 g/dL at diagnosis were correlated with progression-free survival. No remission at the time of transplantation, bone marrow positivity at diagnosis, and relapse after AHSCT were significant parameters for overall survival. CONCLUSION: The major factors affecting the progression-free and overall survival were clearly demonstrated. A CIPI that uses a lactate dehydrogenase level of 500 IU/L worked well for estimating the prognosis. We recommend AHSCT at first complete remission for relapsed cases, and it should also be taken into consideration for patients with high prognostic scores at diagnosis.

Evaluation of telomerase mRNA (hTERT) in childhood acute leukemia.

Human telomerase reverse transcriptase (hTERT) is the catalytic component of telomerase enzyme and has been shown to be associated with telomerase activity (TA). Although many studies in adult leukemia have established the importance of TA, very few have been reported in the children. In this study hTERT levels in childhood leukemia was evaluated and compared with the prognostic factors described before. The LightCycler instrument was used (online real-time PCR) for the quantification of hTERT in peripheral blood and bone marrow in 23 cases with acute lymphoblastic leukemia (ALL) and in 8 cases with acute myeloblastic leukemia (AML). Ten cases with normal peripheral blood (PB) and bone marrow (BM) were selected as control group. Cytogenetic analyses were available in 21 patients with leukemia. In all cases with acute leukemia and in control group, peripheral blood (PB) hTERT levels correlated significantly with bone marrow (BM) hTERT levels. Before treatment, patients with ALL had significantly higher hTERT levels than that of AML patients and control cases. Among patients with ALL, higher hTERT levels were observed in patients with pre-B leukemia, followed by B cell and T cell leukemia patients. Initially increased hTERT levels decreased to the nearly normal levels during remission in cases with ALL. No correlation was observed between the initial hTERT levels and the known prognostic factors except cytogenetic findings. Higher hTERT levels were detected in patients having karyotypic abnormalities which indicate poor prognosis. hTERT levels are significantly high in childhood ALL with the highest level of pre-B cell leukemia before treatment. Those high levels of hTERT decrease to almost normal levels in remission. hTERT levels might be useful in monitoring of leukemia in children.

Polycythemia vera in a 12-year-old girl: a case report.

A case of a 12-year-old girl presenting with headache and splenomegaly and fulfilling the diagnostic criteria of polycythemia vera is reported. Her peripheral blood values were as follows: hemoglobin 18 g/dL, red blood cells 7,000,000/mm3, while blood cells 22,000/mm, and platelets 1,248,000/mm3. Phlebotomy was performed initially but was ineffective. Afterward 100 mg/kg per day aspirin and 30/mg/kg per day hydroxyurea were given. The patient has been asypmtomatic for 1 year and her recent hemoglobin level is 15.5 g/dL, platelet count 922,000/mm3, and white blood cell 12,800/mm3. Polycythemia vera is an extremely uncommon disease in childhood and for this reason its treatment is not well established.

Analysis of pediatric thrombotic patients in Turkey.

This study analyzes the data of thrombotic children who were followed up in different pediatric referral centers of Turkey, to obtain more general data on the diagnosis, risk factors, management, and outcome of thrombosis in Turkish children. A simple two-page questionnaire was distributed among contact people from each center to standardize data collection. Thirteen pediatric referral centers responded to the invitation and the total number of cases was 271. All children were diagnosed with thromboembolic disease between January 1995 and October 2001. Median age at time of first thrombotic event was 7.0 years. Of the children 4% of the cases were neonates, 12% were infants less than 1 year old, and 17% were adolescents. Thromboembolic event was mostly located in the cerebral vascular system (32%), deep venous system of the limbs, femoral and iliac veins (24%), portal veins (10%), and intracardiac region (9%). Acquired risk factors were present in 86% of the children. Infection was the most common underlying risk factor. Inherited risk factors were present in 30% of the children. FVL was the most common inherited risk factor. Acquired and inherited risk factors were present simultaneously in 19% of the patients. Eleven children had a history of familial thrombosis. Due to the local treatment preferences, the treatment of the children varied greatly. Outcome of the 142 patients (52%) was reported: 88 (62%) patients had complete resolution, 47 (33%) had complications, 12 (9%) had recurrent thrombosis, and 34 (24%) died. Three children (2.1%) died as a direct consequence of their thromboembolic disease. The significant morbidity and mortality found in this study supports the need for multicentric prospective clinical trials to obtain more generalizable data on management and outcome of thrombosis in Turkish children.