Objective. To determine a possible assessment of the verification of the genetic group of medulloblastomas based on MRI imaging and quantitative assessment indicators. Materials and Methods . MRI data of 60 patients with a verified molecular genetic subgroup based on the expression level of selected genes on the Nano String platform were retrospectivel analyzed. Results. Based on MRI signs of the shape and contrast intensity of the tumor, taking into account the age of the patients, 76 % of medulloblastomas were correctly identified by genetic groups. Conclusion . The ability to predict the genetic group of the disease in children with medulloblastoma during an initial MRI study with an accuracy of 76 % seems to us important and relevant. Only the first steps have been taken in the development of radiogenomics of medulloblastomas in children. The classification of CNS tumors with the molecular subgroups of medulloblastomas has allowed modern pediatric oncological practice to apply a differentiated approach to stratification of risk groups and prognosis of the disease. This affects the determination of the scope and the tactics of treatment. The aim of our study was an attempt to systematize and definition the diagnostic radiological signs of the currently known four molecular subgroups of medulloblastomas in children. Thirty-nine (76%) patients diagnosed with medulloblastoma were correctly classified into genetic groups based on radiographic features of shape, contrast intensity, and patient age.

Medulloblastoma (MB) recurrence can manifest in various clinical ways and still remains a major therapeutic challenge. As reported in the international literature, high-dose chemotherapy (HDCT) with autologous hematopoietic stem cell transplantation (auto-HSCT) has low effectiveness and severe toxicity in patients with recurrent MB. Here, we analyzed the effectiveness and tolerability of HDCT with auto-HSCT in 9 pediatric and adolescent patients with MB relapses whose histological samples and magnetic resonance images had been reviewed at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology from July 2013 till December 2021. The aim of the study was to evaluate the effectiveness of the HDCT with auto-HSCT approach for the treatment of MB relapses in pediatric patients. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of Russia.

INTRODUCTION: Extracranial neurogenic tumors in children are represented by neoplasms of the sympathetic nervous system and adrenal medulla: ganglioneuromas, ganglioneuroblastomas and neuroblastomas. The main prognostic factors used to stratify patients into risk groups and, in many ways, determine the effectiveness of treatment are the histological type of the tumor and the presence of MYCN gene amplification.OBJECTIVE: To evaluate the capabilities of quantitative MRI to determine the histological variant of neurogenic tumors and predict the presence of MYCN gene amplification in children.MATERIALS AND METHODS: We retrospectively analyzed the data of 110 patients with primary peripheral neurogenic tumors who underwent therapy or received an advisory opinion at the D.Rogachev National Medical Research Center for Pediatric Orthopedics and Pediatric Orthopedics in the period from 2012 to 2022. with diagnoses of ganglioneuroma — 12, mixed ganglioneuroblastoma — 10, neuroblastoma — 88. The age of patients at the time of diagnosis ranged from 15 days to 16 years, median age — 17 months. Before surgery and therapeutic interventions, all patients underwent diffusion-weighted MRI and a tumor biopsy to determine MYCN gene amplification using FISH.Statistics: To determine the threshold values of the apparent diffusion coefficient (ADC) of neurogenic tumors of various histological structures, as well as with the presence and absence of MYCN gene amplification, ROC analysis (receiver operating characteristic) was used. Differences in qualitative parameters in the studied groups of patients were analyzed using the χ2 test, and quantitative ones — using the Mann-Whitney and Kruskal-Wallis tests.RESULTS: Threshold values of the ADC index were determined to reliably differentiate neurogenic tumors rich in Schwann stroma (ganglioneuromas and ganglioneuroblastomas, ADC≥1.25 mm2/s) and neuroblastomas, as well as neuroblastomas without MYCN gene amplification (0.782/s) and with the presence of amplification (ADC≤0.78 mm2/s). In the first case, sensitivity was 0.95, specificity — 0.94; in the second — 0.94 and 0.75, respectively.DISCUSSION: Our data indicate the possibility of separating histological types of neurogenic tumors on the basis of quantitative MRI; the ADC value makes it possible to differentiate ganglioneuromas and ganglioneuroblastomas from neuroblastoma, as well as to distinguish neuroblastoma with the presence of MYCN gene amplification and without this genetic event. Non-invasive quantitative MRI makes it possible to assess the entire tumor volume at the diagnostic stage, and an extremely low ADC value radiogenomic sing for the presence of MYCN gene amplification in neuroblastoma.CONCLUSION: Quantitative MRI with determination of ADC of neurogenic tumors allows not only to separate the histological variants of neurogenic tumors, but also to predict the presence of MYCN gene amplification as the most unfavorable genetic marker of neuroblastomas.

Treatment of patients with high-risk neuroblastoma (NB) is a complex challenge, and it is based on response to certain elements of therapy. The development and introduction of new treatment approaches, such as GD2-targeted immunotherapy (IT), leads to improved survival in this cohort of patients. The aim of the study was to retrospectively assess the effectiveness of therapy in patients with high-risk NB before the introduction of IT into clinical practice. We retrospectively analyzed the data of 151 NB patients stratified into a high-risk group who had received treatment in accordance with the modified NB2004 protocol of the German Society for Pediatric Oncology and Hematology (GPOH) at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology from 01.2012 to 12.2017. This study was approved by the Independent Ethics Committee and the Academic Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. All the study subjects (or their legal representatives) signed a voluntary informed consent form indicating their agreement to treatment and use of their data for research purposes. Overall survival (OS), event-free survival (EFS), and risk factors were analyzed in the patients with high-risk NB including those who had completed multimodal therapy with autologous hematopoietic stem cell transplantation and post-consolidation therapy with isotretinoin and had achieved a satisfactory response to induction therapy (complete response (CR), very good partial response (VGPR), partial response (PR)) (population of special interest). The main unfavorable prognostic clinical and molecular genetic factors affecting survival in the high-risk NB patients were older age, MYCN gene amplification, and stage 4 of the disease. The use of the modified GPOH NB2004 protocol resulted in a satisfactory response (CR/VGPR/PR) to the induction therapy in most patients: 124/151 (82.1 %). Surgery (other than primary tumor biopsy) led to improved survival, with no statistical difference between macroscopic radical surgery and macroscopic residual tumor. At the same time, radiation therapy (RT), as the second element of local control, had a significant impact on EFS in the group of the patients with stage 4 disease: the 3-year EFS was 39.4 % (95 % confidence interval (CI) 23.1–55.4) in the patients with RT versus 25.7 % (95 % CI 17.5–34.7) in the patients without RT (p = 0.0295). The introduction of a new high-dose TreoMel chemotherapy regimen did not result in worse survival rates but led to a decrease in transplant-related toxicity. The 5-year OS and 5-year EFS were 49.4 % (95 % CI 40.9–57.3 %) and 33.3 % (95 % CI 25.9–40.9) respectively for all the study subjects, and 81.6 % (95 % CI 70.3–88.9) and 55.1 % (95 % CI 43.1–65.5) respectively for the patients from the population of special interest. The analysis of the results of therapy in the high-risk NB patients who had received treatment at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, yielded results comparable to those of the original GPOH NB2004 protocol. The patients with CR/VGPR/PR to the induction therapy who had completed the protocol treatment with autologous hematopoietic stem cell transplantation and isotretinoin post-consolidation therapy demonstrated higher 5-year EFS rates. However, there remains a need to develop more effective treatment regimens for high-risk NB.

Mucormycosis is a rare invasive fungal infection most commonly seen in patients with oncological and hematological diseases, when receiving chemotherapy treatment especially in the neutropenic phase. Early diagnosis and timely initiation of treatment are extremely important to improve the prognosis and survival of the patient. In this article, we present a clinical case of a very rare variant of disseminated mucormycosis with involvement of the spleen and mediastinum in a 21-month-old child due to Lichtheimia spp.

Aplastic anemia is a life-threatening condition characterized by the suppression of all hematopoietic lineages in the bone marrow. Empty intertrabecular spaces are replaced by adipose tissue. With modern MR techniques for assessing fat fraction, it has become possible to capture these changes. The fat fraction is estimated as the ratio of the signal intensity from fat to the sum of the fat and water signals. Aim of the study: to assess the diagnostic value of bone marrow fat fraction quantification in patients aged < 18 years with aplastic anemia. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of the Ministry of Healthcare of the Russian Federation. The study included 66 participants aged under 18 years. A control group consisted of 33 healthy subjects with a mean age of 13.03 ± 2.83 years. A group of interest included 33 children with a confirmed diagnosis of aplastic anemia, with a mean age of 12.31 ± 4.39 years. The study was carried out at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of the Ministry of Healthcare of the Russian Federation; all scanning was performed on a Philips Achieva 3.0T MRI scanner using the mDixon-quant sequence in the iliac bones and lumbar vertebrae. Our results showed that bone marrow fat fraction was significantly higher in the aplastic anemia group than in the controls. In the patients with aplastic anemia, the mean fat fraction values in the iliac bones and in the L4, L5 vertebrae were 82.62 ± 10.92% and 73.52 ± 17.52%, respectively. In the control group, the mean fat fraction values for these sites were 51.04 ± 11.41% and 31.43 ± 10.61%, respectively. We found a significant difference in fat fraction values for the same sites between the groups ( p < 0.01). Bone marrow fat fraction quantification by MRI allows for the detection of decreased cellularity of the marrow in patients under 18 years of age with aplastic anemia compared to healthy children.

The aim of the study was to evaluate fat fraction (FF) changes in patients diagnosed with acute lymphoblastic leukaemia (ALL) in comparison with children without haematological disorders. All the patients or their legal representatives gave their informed consent to magnetic resonance imaging (MRI). The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology and was conducted in line with the Ethical Principles of the World Health Organization (the Declaration of Helsinki) for Medical Research Involving Human Subjects. The study included 33 healthy volunteers aged 13.4 ± 2.8 years (the control group) and 34 patients with acute phase ALL whose mean age was 12.2 ± 3.6 years (the group of interest). Imaging of the pelvic bones and lumbar vertebrae was performed on a Philips Achieva 3T scanner using the mDixon-quant sequence, with a subsequent construction of FF maps. The Mann–Whitney U-test was used to compare the FF data of the cases with each other and with the controls. Four regions of interest were selected, 100 mm2 each: in the bodies of the right and the left iliac bones as well as in the bodies of the L4 and L5 vertebras. For each group of subjects and each region of interest, mean FF was calculated. In the group of the patients with acute phase ALL, FF was the lowest: 3.53 ± 2.75% and 3,72 ± 3.09% in the bodies of the left and right iliac bones respectively, and 2.62 ± 1.86% and 2.47 ± 2.17% in the L4 and L5 vertebras respectively. In the control group, FF in the respective regions of interest was 51.3 ± 9.5%; 49.9 ± 11.0%; 31.3 ± 8.73% and 32.4 ± 10.3%. It is obvious that bone marrow FF in the patients with ALL differs significantly from the control group. Quantitative MRI can become a new method for the assessment of changes in the bone marrow of children with leukaemias.

НМИЦ детской гематологии, онкологии и иммунологии им

Low survival rates in children with recurrent medulloblastoma (MB) necessitate the search for new therapeutic approaches as alternatives to the existing treatment standards. Favorable dosimetric characteristics of stereotactic radiation techniques justify the use of such treatments for local radiation control in children with oligometastatic recurrent MB. Given the constant risk of metastatic dissemination and in order to potentiate response to radiation therapy and improve progression-free survival, metronomic molecular-targeted antiangiogenic therapy (MEMMAT, Medulloblastoma European Multitarget Metronomic AntiAngiogenic Trial) can be considered in children with recurrent/progressive MB. Here, we report 2 clinical cases that demonstrate the effectiveness of the treatment approach involving stereotactic irradiation followed by the metronomic MEMMAT regimen for oligometastatic recurrent MB in pediatric patients. The patients’ parents gave consent to the use of their child's data, including photographs, for research purposes and in publications.

Evaluation of the apparent fat fraction (FF) changes in patients at different stages of leukemia treatment compared with children without hematological disorders. The study included 24 healthy volunteers (control group), 40 patients with leukemia: 20 in the acute phase of the disease and 20 patients after chemotherapy in hematopoietic aplasia. Four regions of interest were chosen in size of 150 mm 2 : in the body of the right and left iliac bones, as well as in the bodies of L4 and L5 vertebras. FF significantly changes in patients with leukemia regarding the control group. Quantitative MRI images is a new method for assessing changes in the bone marrow of children with leukemia.

РОЛЬ КТ В ОПРЕДЕЛЕНИИ ОБЪЕМА ОПЕРАЦИИ И ПОСЛЕОПЕРАЦИОННЫЙ МОНИТОРИНГ У ПАЦИЕНТА С НЕЙРОБЛАСТОМОЙТерновая Е.С. 1 , Терещенко Г.В. 1 , Рубцова Н

Congenital neuroblastoma (NB) accounts for 5 % of the total number of patients with this diagnosis and is characterized by a favorable remote prognosis. Most patients are stratified into a low-risk group and do not need chemotherapy. However, in some cases, at stage 4S the disease may develop life-threatening symptoms. Objective of the study: development of an algorithm for prenatal diagnosis and management of patients after birth with NB diagnosis. Materials and methods of research: the study includes 29 patients with a diagnosis of «neuroblastoma», first suspected during ultrasound of the fetus. Therapy and dynamic observation were carried out at the National Scientific and Practical Center for Pediatric Hematology, Oncology and Immunology named after Dmitry Rogachev (Moscow, Russia) from January 2012 to July 2021 (115 months). The stage of the disease was established in accordance with international criteria (G.M. Brodeur, 1993). Stratification for risk groups and therapy was carried out according to the recommendations of the modified protocol of the German group for the treatment of NB-2004. Results: the median of the gestation period at the time of detection of pathological changes in the fetus in 25 cases was 36 weeks (spread 28–40 weeks). In 4 patients, the exact period of detection of prenatal formation was not specified in medical documents. The most frequently detected pathology was interpreted as a voluminous formation of retroperitoneal space – 20/29 (70%) cases, in 7/29 (24%) – as the formation of the abdominal cavity and in 2/29 (6%) – as a chest formation. The delivery naturally was carried out in 17/29 (57.7%), in 12/29 (42.3%) a cesarean section was performed. Median age at diagnosis of «neuroblastoma» amounted to 1.9 months (spread 0.4–12.7 months). Lesions of the adrenal glands were the most commonly noted – 26/29 (89.7%), including bilateral – 8/26. Primary tumor was localized in the posterior mediastinum in 2 patients (6.9%), in one case retroperitoneally – (3.4%). No adverse cytogenetic markers were detected in any case. The first stage of the disease was established in 17/29 (58.6%) of patients, in one case, at the 2–4th stage, this stage was detected in 9/29 (31%) children. 28 (96.6%) out of 29 children were stratified into the observation group, one (3.4%) patient – into an intermediate risk group. In 3/29 (10.3%) of patients, the development of relapse/progression was noted. All patients are alive with median observation of 46.9 months (spread 3.5–99.6 months). Conclusion: Patients with intrauterine NB have favorable biological and cytogenetic characteristics of the tumor. The multidisciplinary approach in management of such patients from the moment of detection of fetal pathologies to the diagnosis of NB and following dynamic observation result in high survival rates.

Risk-adapted therapy is the standard of care for hepatoblastoma (HB). The aim of this study was to analyze the effectiveness of cisplatin monotherapy in patients with standard-risk HB. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation. For the period 02.2012–12.2019 (95 months) 60 patients with standard-risk HB aged 0–8 years were treated within the framework of the cooperation of Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation and B.V. Petrovsky Russian Scientific Center of Surgery. The SIOPEL criteria were used for stratification into risk groups. Throughout the study period, standard-risk patients received therapy per SIOPEL-3 SR protocol, including cisplatin monotherapy. Survival was assessed by the Kaplan–Meier method. For the purposes of this study, overall survival (OS), event-free survival (EFS), where any modification of chemotherapy regimen towards its escalation were considered as an additional event, and progression-free survival (PFS) were calculated. The survival analysis was carried out on 15.01.2021; 54/60 (90%) patients were treated with cisplatin monotherapy and included in the final analysis. Median age at diagnosis was 11.3 (range 0.0–87.7) months. Male:female ratio – 0.86:1. Distribution by PRETEXT stages: I – 14 (25.9%), II – 30 (55.6%), III – 10 (18.5%) patients. The median alphafetoprotein level at the time of diagnosis was 162 979 (range 129–2 000 000) ng/ml. Modification of therapy without confirmed relapse/progression was required in 3/54 patients. Median follow-up was 47.1 (range 2–99) months. Among 54 patients 52 (96.3%) are alive, 2 (3.7%) patients died (1/2 – complications of surgical treatment). Relapses/progressions were noted in 4/54 (7.4%) patients, one of whom died due to disease progression. The three-year OS was 98.1% (95% confidence interval (CI) 94.6–100), EFS – 85.1% (95% CI 75.5–94.6), PFS – 90.5% (95% CI 82.5–98.4). Our data are consistent with the original studies of the SIOPEL group and convincingly confirm the effectiveness of cisplatin monotherapy in patients with HB of the standard risk group in the Russian Federation. Currently this regimen is incorporated into the national clinical guidelines of HB therapy and considered as a standard of care.

The article is devoted to an extremely rare variant of type I interferonopathies associated with a homozygous gain of function (GOF) mutation in the STAT2 gene in a 5-year-old child. This genetic defect was first described in 2019, and so far only 3 cases are known in the world with a similar pathology. Here we present the fourth clinical case and our experience in managing a patient with STAT2 GOF. The article presents the key aspects of the pathogenesis, clinical picture based on the analysis of all known cases of the disease. The absence of established criteria and methods of treatment for this disease is due to the rarity and relative novelty of the described nosology. We present the experience of treatment using a JAK kinase inhibitor, followed by an assessment of the effectiveness of the therapy and side effects. The patient's parents agreed to use the information, including the child's photo, in scientific research and publications.

The aim of the study is to assess the difference in apparent diffusion coefficient (ADC) values depending on the degrees of malignancy of Wilms’ tumor. The study includes 64 patients with verified Wilms tumor after a course of chemotherapy, before undergoing surgical treatment. The patients were examined using scanners with magnetic field induction of 3.0 and 1,5 T. ADC data collection (mm2/s) was carried out using specialized software. Statistical analysis was performed using the Graphpad Prism software package. Based on the results of this study, average ADC values were obtained for histological types of Wilms’ tumors distributed by clinical risk groups: 0.4 × 10-3 mm2/s — for the low grade of malignancy, 1.1 × 10-3 mm2/s — for the average grade of malignancy and 0.6 × 10-3 mm2/s — for the high grade. In addition, for the average grade of malignancy, the ADC values were divided into groups depending on the cellular composition — 1 ± 0.2 × 10-3 mm2/s — for the regressive and mixed type; 0.9 ± 0.2 × 10-3 mm2/s — for the epithelial type; 1.3 ± 0.4 × 10-3 mm2/s — for the stromal type. Thus, diffusion-weighted MRI can be a useful tool in the initial assessment and differential diagnosis of patients with Wilms tumor.

Neuroblastoma (NB) is the most common extracranial tumor in children. In 5–15% of cases, the tumor extends into the spinal canal and can potentially cause neurological deficits and orthopedic problems that can develop both at the onset of the disease and at a later time. We analyzed data of 61 patients with NB and intraspinal extension who had been treated at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology over the period from Jan 2012 to Dec 2018. The study was approved by the Independent Ethics Committee and the Scientific Council of the D. Rogachev NMRCPHOI. The treatment was delivered in accordance with the NB-2004 protocol. In all the children, magnetic resonance imaging and/or computed tomography of the CNS were performed to evaluate intraspinal extension of the tumor as well as the degree of spinal cord compression. The presence of scoliosis and its severity were determined at the baseline and at 2 years after the diagnosis using imaging data and Cobb angle measurement. Scoliosis was classified as mild if the Cobb angle was 10–25°, moderate if it was 25–40°, and severe if it exceeded 40°. In our study, 7/61 (12%) patients were diagnosed with scoliosis at the baseline assessment. The median age at diagnosis was 8.0 (2.3–11.8) months. The male to female ratio was 2.5:1. In 4/7 (57%) patients, the primary tumor was located in the retroperitoneum (outside the major organs), and in 3/7 (43%) patients – in the posterior mediastinum. In this group, 4/7 (57%) patients had INSS stage 2 or 3 tumors, 2/7 (29%) patients had stage 4 disease, and 1/7 (14%) had INSS stage 4S. The majority of patients (5/7 (71%)) were stratified into an observation group. In 6/7 (86%) patients, the tumor extended into the spinal canal involving the thoracic spine. In 6/7 (86%) cases, there was evidence of complete obstruction of the spinal canal. Neurosurgery was performed in 4/7 (57%) patients. All these patients were diagnosed with mild scoliosis at the baseline. At 2 years after the diagnosis, imaging data were available for 38/54 (70%) patients who had not had scoliosis at the baseline. This time, scoliosis was diagnosed in 9/38 (24%) cases. The median age at NB diagnosis was 8.2 (0.8–42.3) months, the male to female ratio was 2:1. In 7/9 (78%) patients, the primary tumor was located in the posterior mediastinum. The majority of patients were stratified into an observation group (7/9 (78%)). In 8/9 (89%) patients, the tumor extended into the spinal canal involving the thoracic vertebrae. In the majority of patients (4/9(44%)), the tumor filled 33 to 66% of the spinal canal. Neurosurgery was performed in 6/9 (67%) patients. In this group, 7/9 (78%) patients were diagnosed with mild scoliosis and 2/9 (22%) patients – with moderate scoliosis. NB with intraspinal extension can lead to various orthopedic problems including scoliosis that can be revealed both at the onset of the disease and at a later time, meaning that this condition requires a multidisciplinary approach involving orthopedic specialists.

Chronic granulomatous disease (CGD) is a primary immunodeficiency (PID), characterized by a defective production of reactive oxygen species by phagocytes. Infectious diseases are a classic manifestation of this form of PID; however, many patients present with a variety of inflammatory and immune non-infectious complications. We analyzed non-infectious complications in a group of 60 patients with CGD, who were treated in Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology (Moscow, Russia) since 2012 to February 2020. This study is supported by the Independent Ethics Committee and approved by the Academic Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. Non-infectious manifestations were recorded in 53/60 patients, the most frequent of which were granulomatous complications (81.7% (49/60) of cases) in the following organs - the gastrointestinal tract, lungs, liver and lymph nodes. The median age of granulomas presentation was 3 years, and 45.8% of patients had a combined granulomatous lesion of several organs. Hepatomegaly (40%), splenomegaly (31.7%), dermatitis (21.7%) and chorioretinal lesions (11.3%) were other non-infectious complications. Hematological features outside acute infectious episodes included monocytosis (26.7%), eosinophilia (20%), neutrophilia (13.3%). 96.7% of patients had anemia with a decrease level of serum iron (65%), 31.7% - with signs of hemolysis. Autoimmune manifestations included arthritis, thyroiditis, immune thrombocytopenia or immune neutropenia. Non-infectious complications comprise a significant part of the CGD manifestations and often are the first symptoms of the disease. Awareness of this fact is very important for multidisciplinary approach in treatment of CGD. Delayed diagnosis and immunosuppressive therapy of non-infectious complications without prophylactic antimicrobial therapy can be life-threatening for patients with CGD.

1ФГБУ «Национальный медицинский исследовательский центр детской гематологии, онкологии и иммунологии им. Дмитрия Рогачева» Минздрава России, Москва 2ФГАОУ ВО «Российский национальный исследовательский медицинский университет им. Н.И. Пирогова» Минздрава России, Москва 3ГУ «Республиканская детская клиническая больница» Министерства здравоохранения Республики Коми, Сыктывкар 4ГБУЗ «Самарская областная детская клиническая больница им. Н.Н. Ивановой», Самара

Background. Diffuse leptomeningeal glioneuronal tumor (DLGNT) is an extremely rare entity first officially recognized in 2016 WHO classification of tumors of the central nervous system. Magnetic resonance imaging (MRI) of this tumor usually visualizes diffuse meningeal infiltration with contrast enhancement, with the presence of multiple small contrast‑negative cysts, visible mainly in the T2 images. The main molecular markers of DLGNTs include the KIAA1549-BRAF fusion gene, BRAF V600E substitution is less common.The aim of this work is to describe the manifestation of DLGNT, its neuroimaging and molecular genetic characteristics, the experience of using anti‑BRAF and anti‑MEK therapy.Materials and methods. In this article are described four cases of DLGNT. The first patient with the presence of the KIAA1549-BRAF fusion in the tumor tissue received a full course of SIOP‑LGG / 2004 chemotherapy (carbo‑ platin and vincristine), the stabilization of the disease on the MRI remains for 4 years after completion of treatment. Second patient with KIAA1549-BRAF fusion gene in tumour tissue received MEK inhibitor trametinib as first line of treatment with the stabilization of the disease on control MRI which last for 2 years. A third patient with a mutation in the BRAF V600E gene. After disease progression on standard chemotherapy (carboplatin and vincristine) according to the SIOP‑LGG / 2004 protocol, anti‑BRAF therapy with vemurafenib was prescribed. After 10 months on MRI a complete response was recorded, which persists during the drug intake for 2.5 years. In the fourth patient, no molecular genetic aberrations were detected; a refractory / progressive course of the dis‑ ease was noted. To date, the stabilization of the disease is recorded on the fourth line of chemotherapy (everoli‑ mus and temozolomide).Conclusion. Given the rarity of this tumor and the lack of consensus about therapy, despite the limited number of observations, our experience allows us to recommend molecular testing of DLGNT to detect activating events in the BRAF gene, as well as consideration of anti‑BRAF / MEK therapy if either the BRAF V600E mutation is de‑ tected or KIAA1549-BRAF fusion.

The article is devoted to the description of the X-ray anatomy of the mediastinum, the evolution of the classification of this anatomical region. As well as systematization of radiological signs of the most common formations of the anterior (prevascular) mediastinum in children. Based on these data, a table of the most characteristic radiographic features of various neoplasms of different groups. Reflected basic criteria differential diagnosis of various tumors of the anterior mediastinum.