Introduction. Allogeneic haematopoietic stem cell transplantation (HSCT) is actively used in clinical practice for the treatment of various diseases. Recipients of allogeneic HSCT require significant amounts of transfusion therapy, but the real need for transfusions and factors influencing this need have not been assessed in domestic practice.

Materials and methods. A retrospective analysis of the need for transfusions of blood components of recipients of the first allogeneic HSCT performed in 2018–2022 during the observation period of 1 year was performed. The volumes of transfusions performed were calculated for each type of blood components. The transfusion-dependent period is represented by the number of days until the transfusion independence criteria were reached. The incidence of loss of transfusion independence is presented. The influence of various factors on transfusion requirement and transfusion independence was assessed.

Results and discussion. The median number of red blood cells transfusions was 2 (IQR 1–4), the median number of platelet transfusions was 5 (IQR 3–10). The only factor that influenced the volume of transfusion therapy was the type of diagnosis more transfusions were required for nonmalignant diseases. The duration of the transfusion-dependent period was influenced by the type of diagnosis, haematopoietic stem cell source and donor type. Gender differences between donor and recipient, as well as differences in ABO and conditioning regime did not influence either transfusion requirement or independence from transfusions.

Conclusion. This analysis presents the need for transfusions of donor blood components in allogeneic HSCT recipients during 1 year.

The results of the analysis can be used for planning the activities of transplantation centres and blood service institutions to provide transfusion support for HSCT recipients.

Background. Neuroblastoma (NB) with primary tumor located in the posterior mediastinum is a unique subgroup characterized by a higher incidence of life-threatening complications, such as epidural compression (EC) and respiratory failure, yet it is associated with favorable long-term outcomes.

Materials and methods. The study included patients with low-risk posterior mediastinal NB treated at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology between January 2012 and September 2024 (152 months). Patients were stratified into risk groups and managed according to the GPOH-NB2004 protocol. We evaluated relapse/progression detection methods, disease characteristics, treatment approaches, and long-term outcomes.

Results. The study included 146 patients with NB with primary tumor located in the posterior mediastinum, which is 21.6 % of all patients in the observation (low-risk) group registered in the research database of Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. The median age at diagnosis was 19.6 months (range 0.5–132.5 months) with a female predominance (male-to-female ratio 1:1.2). Most patients (85/146; 58.2 %) presented with stage 2 disease. 38/146 (26.0 %) patients received chemotherapy due to life threatening symptoms, primarily EC, while 87/146 (59.6 %) patients underwent best surgery in the volume of a macroscopic residual tumor. Relapse/progression occurred in 16.4 % (24/146), predominantly detected during routine follow-up imaging (18/24; 75,0 %), with a median time to relapse of 7.8 months (range 3.0–25.3 months). The majority of relapses/progressions were local (18/24; 75.0 %). In 93 % (14/15) of relapsed/progressed cases analyzed retrospectively, MLPA revealed segmental chromosomal aberrations (median 3 aberrations/ patient; range 0–6). The most frequent alterations included 17q gain (n = 11), 2p gain (n = 8), and deletions in 3p (n = 6), 11q (n = 5), and 4q (n = 4). The 5-year event-free survival in patients with mediastinal NB was 79,1 ± 4,0 %, patients with stage 1 showing the highest survival rates (90 ± 6 %) (p = 0.1932). The 5-year overall survival was 95,0 ± 2,1 %. The cumulative incidence of relapse/progression was 18.7 ± 3.5 %, while treatment-related mortality was 2.8 ± 1.4 % (one death from disease progression; five from therapy toxicity).

Conclusions. Mediastinal NB is a prognostically favorable group, with excellent survival rates independent of age or stage. Most patients in the low-risk group achieved favorable outcomes, even after relapse/progression. For the majority of patients in the low-risk group, surgery only is sufficient, and this strategy allows to reduce the risk of mortality from the toxicity of therapy without reducing overall survival.

However, chemotherapy remains critical for patients with life-threatening complications, such as EC and respiratory failure, which once again highlighting the challenges in managing this subgroup. Strict adherence to the entire follow-up plan during the period of catamnesis is essential for early relapse detection. The molecular profile of the tumor may predict relapses and treatment response, which underscores the need to integrate molecular diagnostic methods (MLPA) to all patients with NB in the low-risk group into routine diagnostics.

Introduction. Retinoblastoma (RB) is the most common primary intraocular tumor in childhood. One of the most effective ways of targeted drug delivery directly to the tumor is selective intra-arterial chemotherapy (SIAC). No studies have been found in the world literature that would conduct a detailed assessment of this method of treating intraocular RB in infants under 6 months.

Objective – to evaluate the safety and efficacy of SIAC for the treatment of infants under 6 months of age diagnosed with intraocular RB.

Materials and methods. A single-center, retrospective cohort study was conducted, which included 19 infants (63 sessions of SIAC) who were diagnosed with unilateral or bilateral intraocular RB at the age of up to 6 months and underwent primary or secondary SIAC from December 2017 to November 2020.

Results. The main results included the technical success rate of SIAC, survival rates and adverse events. The age group up to 6 months is represented by 19 patients, in 4 cases with a familial form of RB. The number of boys was 5 (26.3 %), girls – 14 (73.7 %), aged from 0.5 to 5 months (median 3 (2; 5) months), the average weight was 7.13 (median 7.25 (5; 9) kg). 26 affected eyes in 19 patients underwent SIAC.

SIAC was performed primarily in 10 (52.6%) of 19 patients (13 affected eyes). Out of 9 (47.4 %) pretreated patients (13 affected eyes), before SIAC, in 5 cases (8 affected eyes) only systemic chemotherapy (CT) was performed. In 2 of 9 patients, in addition to CT, additional local treatment of 3 affected eyes was performed. 2 of 9 patients underwent only local treatment of 2 affected eyes. Catheterization was successful in 100 % of procedures (n = 63). Indications for additional treatment after SIAC with organ-preserving goal were required in 20 of 26 cases.

There were no cases of using external beam radiotherapy before and after SIAC. Secondary bilateral enucleation was performed in one patient due to complications after brachytherapy. Among the early systemic complications, cardiorespiratory disorders should be noted, which were observed during 23 (36.5 %) SIAC sessions; and among the remote ocular complications, 2 cases (7.7 %) – chorioretinal dystrophy (spread to 3 or more retinal quadrants). There were no cases of stroke, neurological disorders, extraocular tumor growth and metastasis.

In 3 of 19 patients, pineoblastoma was diagnosed as a metronomic manifestation of trilateral RB. The time from the initial diagnosis of bilateral RB to the occurrence of pineoblastoma in these patients was 2 years 11 months, 4 years 11 months and 2 years 8 months In 1 patient with familial bilateral RB, a second tumor was detected – an incidentoloma of the basal ganglia of the brain on the right after 5 years 6 months. from the initial diagnosis of RB. The overall five-year survival rate of patients was 87.4 ± 8.4 %. The cause of death of 2 patients was progression of metachronous trilateral RB. The overall five-year organ (eye) survival was 91.6 ± 5.7 %.

Conclusions. The results of our study indicate that SIAC, both primary and secondary, is effective and safe enough for the treatment of disseminated RB in infants under 6 months of age. However, possible complications associated with both selective intra-arterial catheterization and CT administration cannot be ignored and require further study.

Introduction. Essential thrombocythemia (ET) is a type of clonal myeloproliferative neoplasm, which is characterized by uncontrolled proliferation of megakaryocytes. It is associated with an increased number of large and giant megakaryocytes in the bone marrow, leading to thrombocytosis and a high risk of both thrombosis and bleeding. Unlike in adults, pediatric patients with ET often do not experience any clinical manifestations of the disease. However, based on data from adult studies, it is possible that ET and polycythemia vera in children can also lead to both thrombotic and hemorrhagic complications. Changes in the hemostatic system are an important factor that can contribute to these risks.

The aim of this study was to evaluate the state of blood coagulation system in children with thrombocytosis and erythrocytosis using standard coagulation tests, aggregometry, global hemostasis assays, levels of von Willebrand factor antigen (vWF:Ag) and activity and markers of endothelial dysfunction.

Materials and methods. Activated partial thromboplastin time, prothrombin time, thrombin time, fibrinogen, antithrombin III, D-dimer, vWF:Ag and activity RCo of von Willebrand factor, platelet aggregation with adenosine diphosphate (ADP), collagen, ristocetin, thromboelastography and thrombodynamics, endothelin-1 and thrombomodulin levels. The concentration of procoagulant micropartocles derived from the patients' plasma was estimated by flow cytometry. 59 patients diagnosed with ET were enrolled in this study. 13 children with secondary thrombocytosis and 23 with erythrocytosis were enrolled as the control groups.

Results. The results of routine coagulation tests, as well as measurements of antithrombin III activity, D-dimer levels, vWF:Ag, thrombomodulin and endothelin-1, were within the normal range in most patients. The decrease in platelet aggregation was observed after stimulation with ADP in 29 % of patients, with collagen in 37 %, and with ristocetin in 47 %. A statistically significant correlation was found between the decrease in platelet aggregation and the increase in platelet counts. Increased aggregation was seen with ADP and collagen in only 11 and 18 % of patients, respectively, which may indicate a potential prothrombotic tendency and microcirculatory abnormalities in patients with ET.

Acquired von Willebrand syndrome was present in 54 % of patients. Analysis showed that among patients with extreme thrombocytosis (> 1500 × 109/L), all had acquired von Willebrand disease. In addition, in patients with extreme thrombocytosis, there was an increase in parameters of thromboelastography, such as angle α and maximum amplitude, as well as clot growth rates in the thrombodynamics test.

Correlation analysis showed significant dependences (p < 0.05) between the parameters of thromboelastography and thromobodynamics on both platelet count and number of procoagulant microvesicles.

Conclusions. Despite the differences in clinical manifestations in children with ET, a close correlation has been identified between increased platelet counts and changes in their aggregation function, as well as, between increased platelet counts and changes in global hemostasis assays. All patients with hemorrhagic symptoms had laboratory signs of acquired von Willebrand syndrome.

Backgrond. Venous thrombotic episodes (VTE), both symptomatic (sVTE) and asymptomatic (aVTE), are not uncommon complications of the course and therapy of malignant diseases in children. While the largest number of studies in children is devoted to the problem of VTE in acute lymphoblastic leukemia (ALL), the incidence of thrombotic events in other types of blood diseases remains poorly studied.

The aim of the study – to evaluate the incidence of VTE in children with hemoblastosis and bone marrow aplasia depending on the underlying disease by event-based survival analysis.

Materials and methods. The current study was prospective monocenter observational in nature. We analyzed the cumulative probability of detection (CPD) of VTE, aVTE and cVTE in 1623 pediatric patients hospitalized at the Dmitry Rogachev Center from 01.01.2013 to 31.12.2017.

Results. The 3-year incidence of VTE was 34.8 % (95 % confidence interval (CI) 31.3–38.7). The majority of VTE presented as aVTE: 3-year CPD 28.9 %; 95 % CI 25.7–32.5, and the 3-year CPD with aVTE was more than 3-fold lower: 3-year CPD 8.2 %; 95 % CI 5.8–11.5. While the highest incidence of aVTE was found in children with ALL and lymphomas, followed by myeloleukemia, histiocytosis and bone marrow aplasia. The majority of sVTE episodes were diagnosed in lymphomas followed by ALL, myeloleukemia and histiocytosis.

More than half of sVTE episodes were diagnosed in the first 6 months of treatment, with most episodes in children with lymphomas and myeloleukemia diagnosed in the first 3 months.

Conclusion. The highest incidence of VTE episodes was found in patients with ALL and lymphomas, with most episodes diagnosed in the first 3 months of treatment. The CPD for detecting sVTE in the first 3 months after hospitalization in patients with histiocytosis is comparable to that in ALL. Further prospective studies with the formation of risk-adapted models of primary antithrombotic prophylaxis in children with blood diseases are needed.

This review consolidates current knowledge on genetic alterations observed in pediatric glial and glioneuronal tumors of the central nervous system (CNS). Some of these alterations serve as diagnostic biomarkers, whereas others may inform the selection of targeted therapeutic strategies. Drawing on both diagnostic and clinical perspectives, the authors aim to facilitate a more comprehensive understanding of the WHO Classification of CNS Tumors and to promote interdisciplinary collaboration. This resource is intended to support accurate tumor classification, guide molecular testing, and aid in identifying actionable genetic targets. The content may be of practical value to pediatric neuro-oncologists, molecular pathologists, neuropathologists, and researchers involved in CNS tumor diagnostics and treatment. For user convenience, selected data are summarized in tables.

Current approaches to treating high-risk neuroblastoma include surgery, chemotherapy, radiation therapy, bone marrow transplantation, and immunotherapy. Despite multimodal treatment, the prognosis for this group of patients remains poor: relapse of the underlying disease occurs in 50 % of cases, and over 90 % of these patients die. Therefore, developing effective strategies to prevent relapse is key to improving long-term outcomes. The article presents a review of the use of the drug eflornithine (DFMO) in the treatment of children with high-risk neuroblastoma.

Embryonal tumor of the central nervous system (CNS) with PLAGL1/PLAGL2 amplification is a new type of CNS tumors in children, first described in 2023. They can be localized in any part of the CNS and, as their name suggests, are caused by the amplification of genes of the PLAG family. At present, this tumor is not yet defined as a separate type in the latest edition of the WHO classification in 2021. In the foreign literature, 27 cases of embryonal tumors of the CNS with PLAGL1 and PLAGL2 amplification in children have been described. A single standard of therapy has not yet been developed; the optimal treatment method is resection of the tumor, as well as polychemotherapy in combination with radiation therapy.

This article presents a clinical case of a 2.5-year-old girl with an embryonal tumor with PLAGL1 amplification, describes in detail the treatment tactics and presents an analysis of cases previously described in international literature.

Relevance. Life-threatening conditions in pediatric oncology are caused either by tumor diseases or treatment of a tumor disease (chemotherapy-induced cardiotoxicity after the administration of anthracyclines, high doses of cyclophosphamide, ifosfamide, etc.).

Cardiotoxicity occurs over weeks to months and may manifest as restrictive cardiomyopathy with impaired diastolic function or dilated cardiomyopathy with thinning of the left ventricular wall and development of left ventricular systolic dysfunction. Information on the survival of pediatric patients with malignant neoplasms after veno-arterial extracorporeal membrane oxygenation (VA-ECMO) followed by orthotopic heart transplantation is not found in the published literature.

Purpose of the study – to present the experience of a multidisciplinary and multicenter approach in the treatment of a child with osteosarcoma in the event of life-threatening cardiomyopathy with acute circulatory failure, the use of VA-ECMO and subsequent heart transplantation.

Materials and methods. A description of a clinical case of treatment of a 13-year-old child with relapse of osteosarcoma after primary treatment in 9-year-old. The child underwent 5 courses of polychemotherapy with the inclusion of anthracyclines without exceeding cumulative doses. After completion of treatment, the child was diagnosed with chemotherapy-induced dilated cardiomyopathy, manifested by congestive heart failure and the development of cardiogenic shock. The child was initiated for vital indications VA-ECMO followed by orthotopic heart transplantation within 10 days.

Conclusion. During the time the patient was on ECMO, no significant complications were recorded; the child was in remission of the underlying disease, which made it possible to perform a successful donor heart transplantation with standard immunosuppressive therapy. During the observation period of 14 months, the heart transplant functioned satisfactorily.

Soft tissue sarcomas (SMTs) represent a heterogeneous group of malignant tumors of mesenchymal origin. The widespread introduction of next-generation sequencing techniques, including RNA sequencing, into clinical practice has led to the description of a variety of SMTs with rearrangements of genes encoding various kinases.

The present article describes the clinical case of a 3-year-old patient with a low-grade spindle cell sarcoma with a detectable MYH10::RET RNA transcript. The literature review describes the role of the RET gene in the pathogenesis of malignant neoplasms, with emphasis on soft tissue tumors, and presents the clinical, molecular and genetic characteristics of pediatric cases of SMT with RET gene rearrangements and the results of their therapy. The role of various molecular oncology techniques in the identification of kinase gene rearrangements, including RET, is discussed.

Tumor thrombosis of the main vessels is a rare complication of malignant neoplasms in children. In the world literature, a few clinical cases of thrombosis of the main vessels in hepatoblastoma are noted. This poses questions to the surgeon, the solution of which does not have a single and standardized approach, as well as sufficient clinical experience in pediatric practice. Treatment of patients with such complications requires careful preparation, planning and coordinated work of an interdisciplinary team of specialists. This article presents a clinical case of a child with right liver lobe hepatoblastoma with tumor-associated thrombosis of the right hepatic vein and inferior vena cava, extending to the right atrium. After neoadjuvant chemotherapy, the patient underwent right extended hepatectomy with resection of the inferior vena cava at the level of hepaticocaval confluence and subsequent reconstruction using an autogenic patch.

Neurofibromatosis type 1 (NF1) is an autosomal dominant, highly penetrant disorder caused by pathogenic variants (mutations) in the NF1 gene. Mosaic NF1 is a distinct form of this disorder. Somatic mosaicism in NF1 is a rare condition caused by postzygotic pathogenic variants in the NF1 gene. The article presents a clinical case of mosaic NF1 in a 13-year-old child.