Introduction. Central nervous system (CNS) tumors are the most common pediatric solid tumor, that need multimodality treatment approach including surgery, intensive chemotherapy (CT) and radiotherapy (RT). Due to toxicity, mostly late, RT has limited use in children, especially those under 3 years of age. The physical characteristics of proton beam therapy (PBT) minimize the risk and types of toxicity compared to photons, making it the preferred choice for pediatric use.
   Aim – to analyze the experience of PBT in patients under 18 years of age with various types of CNS malignancies, the assessment of risk factors for acute and late toxicity and its clinical manifestations. Materials and methods. A retrospective analysis of 63 courses of PBT performed in 58 patients with CNS malignancies for the period from 2018 to 2022 was carried out on Proton Center of the Sergey Beresin Medical Institute. The manifestations of local and systemic toxicity (predominantly acute) were analyzed, with an assessment of the influence of age, the volume of RT, the use of previous and concomitant CT on the severity of adverse events (AE).
   Results. In the study cohort, patients with embryonal CNS malignancies predominated (72.3 %). Median age was 5 years 2 months, median follow-up was 15 months. In 36 % of cases, a complete response was achieved by the start of PBT. Patients with craniospinal irradiation (CSI) prevailed (60 %). Among the manifestations of toxicity, AE grade I–II predominated. The most common AE were local reactions (dermatitis (84 %), focal alopecia (96 %)). Among systemic AE, hematological complications (84 %) were the most often occurred. A more pronounced toxicity profile was registered in the group with CSI, while concomitant CT, the patient’s age, previous CT did not significantly affect the severity of most of the assessed AE parameters (p > 0.05). The analysis of late toxic effects was difficult due to the short follow-up period, the cumulative effect of other treatment modalities on the AE’s development. The reported complications included persistent focal alopecia (14 % of cases), endocrinopathies (7 %), neurological manifestations (6 %). One (2 %) child had a severe neurological deficit, secondary epilepsy with psychomotor regression, which can also be associated with the potentiating effect of previous CT and high-dose CT.
   Conclusion. The analysis of our data and literature review allows to conclude that PBT has relatively low toxicity profile, which is the determining factor for choosing this method of RT in pediatric patients. The main risk factor of AE’s was CSI. The acceptable acute toxicity of repeat PBT makes it possible to be used in pts with disease progression or relapse in case of absence of alternative therapeutic options.

   Introduction. Soft tissue tumors account for up to 8 % of all malignant neoplasms in children. According to the international histological classification, about 150 different morphological variants of soft tissue tumors have been registered, of which 45 % are rhabdomyosarcoma (RMS). Most often, RMS occurs in early childhood – the average age of patients at the time of diagnosis is 5 years. The incidence rate of RMS is 0.9 per 100,000 children. In 25 % cases, the initial diagnosis reveals distant metastasis to the lungs, bones, bone marrow, and 8 % – leptomeningeal metastasis. More than 7 % of patients with localized parameningeal RMS develop leptomeningeal metastasis, according to the Rhabdomyosarcoma Study Group.
   Purpose of the study – report the incidence, prognosis of leptomeningeal metastasis and treatment outcomes in children with intracranial spread of RMS.
   Materials and methods. The study included 45 patients aged 1 to 17 years with a diagnosis of RMS of parameningeal localization with intracranial spread, who received special treatment from 2003 to 2020. The study included 6 (20 %) patients in whom the tumor developed in early childhood (up to 3 years). The boys predominated – 25 (55.5 %) in the study. The primary tumor spread to the orbit in 7 (15 %) cases, the skull base in 7 (15 %) cases, the middle ear in 4 (8 %) cases, the nasopharynx in 3 (6 %) cases, and the brain substance was affected in 16 (35 %). Metastases in regional lymph nodes were determined in 7 (15 %) patients. Multiple metastatic lesions of bones and bone marrow – 4 (9 %) cases, leptomeningeal metastases – in 2 (4 %). 45 (100 %) patients received drug treatment according to the protocols approved by the Academic Council of the Research Institute of Pediatric Oncology and Hematology at N. N. Blokhin National Medical Research Center
of Oncology, Ministry of Health of Russia. Radiation therapy was performed in 33 (74 %) patients, while total focal dose of 50 Gy was administered to the primary tumor. Affected lymph nodes of the neck were irradiated in 10 (23 %) patients, total focal dose is 45.0 Gy. Surgical treatment was performed in 15 (34 %) patients. Multicomponent treatment was performed in 15 (34 %) patients.
   Results. During the observation period from 12 months to 14 years, 21 (49 %) patients are alive. 21 (51 %) patients died from tumor progression, 1 (2 %) died from complications of special treatment.
   Conclusions. The treatment of this group of patients is one of the urgent problems of pediatric oncology, which is based on polychemotherapy, supplemented by intrathecal administration of anticancer drugs and craniospinal irradiation. The development of new therapies requires a multidisciplinary approach to achieve a significant improvement in the survival of children with leptomeningeal metastases RMS of parameningeal localization.

   Introduction. Regional blockades in children in ophthalmology operations are used not only for analgesia in the intra- and postoperative period, but also for the prevention of oculocardial reflex (OCR), postoperative nausea and vomiting (PONV). But there is still no convincing data on the advantages of the methods of retrobulbar blockade (RBB) performed under ultrasound guidance and parabulbar blockade (PBB) performed under ultrasound guidance.
   Aim. In the present study, we investigated the efficacy and safety of RBB under ultrasound guidance with ropivacaine 0.5 % for the prevention of OCR and postoperative pain, as well as PONV when detected with PBB of ropivacaine 0.5 % under ultrasound guidance upon detection of enucleation of the eyeball.
   Materials and methods. A prospective randomized arterial study was performed for the period 2016–2022. The study included 110 patients with established inclusion criteria. The patients were divided into two groups: 55 patients who performed a RBB + ultrasound and 55 patients who performed a PBB + ultrasound. Evaluated: the likelihood of the introduction of opioid analgesics, the quality of anesthesia, the duration of the block and the likelihood of complications.
   Results. There was a decrease in intraoperative diseases in the RBB + ultrasound group, where the average dose of fentanyl was increased by 4.1 ± 1.4 μg/kg, and in the PBB + ultrasound group it was 9.7 ± 1.8 μg/kg (p < 0.05 ). The time to the first frequency of the analgesic in the postoperative period was 6.7 ± 1.8 hours in the PBB + ultrasound group, and 11.7 ± 3.3 hours in the RBB + ultrasound group (p < 0.05).
   Conclusions. There was a significant difference in analgesic efficacy between RBB + ultrasound and PBB + ultrasound. It was revealed that RBB + ultrasound reduces intraoperative opioid requirements, stable intraoperative hemodynamics and longer postoperative analgesia. Therefore, the use of RBB + ultrasound for enucleation of the eyeball in children with retinoblastoma is the preferred technique.

   Tumor lesion of the orbit is found in the clinic of various oncohematological diseases in children. Untimely referral of such patients to an oncologist delays the timing of the necessary treatment, thereby worsening the prognosis of the disease. The literature review presents the features of clinical manifestations of orbital pathology in children at the onset of acute myeloid leukemia, myeloid sarcoma, lymphoma, Langerhans cell and non-Langerhans cell histiocytosis. The article presents our own observations and identifies factors that negatively affect the timely diagnosis of oncohematological diseases in this category of patients.

   Background. In some rare cases pediatric solid tumors may infiltrate or incase major vessels, which may require vascular plastics as part of radical tumor resection. As these situations are rare in pediatric surgeon practice, there is no common approach to this problem. In order to analyze the available experience we reviewed published cases concerning vascular plastics in pediatric oncosurgery.
   Materials and methods. The references from MEDLINE (PubMed), HighWire Press, and eLibrary electronic databases were analyzed for references describing practical vascular surgery experience with vascular implants published in 2002–2022.
   Results. There is few published data on major vessels reconstruction in patients with pediatric solid tumors. Most publications describe single cases or small case series. The vascular plastics in these children is difficult due to small vessel diameter, difficulties in choosing the right graft, risk of thrombosis, and the need to provide adequate circulation in a rapidly growing child. As there are no major studies of this subject we still have no consensus on optimal vascular reconstruction tactics in children with solid tumors. Therefore, new systematic studies are needed.
   Conclusion. We provide a brief review on currently used methods of vascular plastics and reconstruction available for use in children with solid tumors.

   Conditioning regimens prior to hematopoietic stem cell transplantation (HSCT) are often accompanied by a period of aplasia characterized by severe neutropenia, anemia, and thrombocytopenia. Long-term antibacterial and immunosuppressive therapy in patients with graft-versus-host disease (GVHD) exacerbates hematopoietic depression. Colony-stimulating factors, erythropoietins, and thrombopoietin receptor agonists are used to correct hematological dysfunction in these patients. However, these drugs have side effects, and their stimulating effect, as a rule, is limited to one of the hematopoietic lineages. At the same time, in patients after HSCT, for the prevention and treatment of hematopoietic disorders against the background of GVHD, it is necessary to use drugs that promote the restoration of all hematopoietic cell lines. Inducers of Toll- and NOD-like receptors, stimulators of emergency hematopoiesis, can be considered as promising drugs for this category of patients. These compounds include bacterial derivatives and sulfated poly(oligo)saccharides capable of stimulating hematopoiesis, which allows us to consider them as promising stimulants of hematopoiesis for the treatment and prevention of disorders of the immune status and hematopoiesis in GVHD.

   The review article is devoted to evaluation of the quality of life of patients with retinoblastoma (RB), in particular children following enucleation of the eyeball. The main methods of cosmetic rehabilitation and psychological support of patients with RB are considered. The analysis of the literature suggests that it is important to pay attention not only to the physical condition, but also to the emotional well-being of patients with RB, and to develop specialized rehabilitation measures.

   Radiation therapy (RT) is associated with high incidence of dermatologic adverse events. Radiation dermatitis is a major cutaneous side effect of RT. The article presents current views on pathogenesis of radiation dermatitis and modern approaches to prophylaxis and treatment of this cutaneous reaction.

   Epithelioid hemangioendothelioma (EHE) is one of the rarest vascular tumor found in the brain. In the pediatric group of patients, the proportion of EHE is only 0.02% of all brain neoplasms, and therefore oncogenesis and the causes are currently not well understood. Intracranial localization of EHE is extremely rare, nevertheless, this type of neoplasm should be included in the differential diagnostic series when multiple small intracerebral masses with hypointense MR signal in T2 mode are detected on magnetic resonance imaging. No specific therapy is currently developed for this disease, the optimal treatment is surgical removal of the volumetric mass if this type of treatment is possible. This article presents a clinical case of a primary multiple CNS lesion in a 14-year-old child with a long history of epilepsy. According to our data, the presented clinical case is the only one registered in the world, with primary multiple CNS EHE of the brain in the pediatric population

   Peritoneal sarcomatosis/carcinomatosis is a rare observation in pediatric practice. It occurs, as a rule, with various sarcomas, sarcomatoid tumors, desmoplastic small round cell tumors. Cytoreductive surgery followed by abdominal chemoperfusion has established itself as an effective method of treating such conditions in adult practice and is gaining popularity in pediatric practice. Laparoscopic cytoreduction followed by hyperthermic chemoperfusion used in adult patients has a number of advantages: early recovery after surgery, reduced hospital days, timely initiation of adjuvant chemotherapy, however, the experience of using a minimally invasive technique in children is limited. The article presents the first clinical observation in Russian practice of a 17-year-old patient with embryonal testicular rhabdomyosarcoma and peritoneal sarcomatosis of the abdominal cavity, which underwent laparoscopic cytoreductive surgery with hyperthermic chemoperfusion.

   Ewing sarcoma (ES) is one of the most frequent primary bone tumors and has a well-studied diagnostically important genetic background. However, there are primary bone round-cell tumors with atypical morphology different from conventional ES, tumors with rearrangement of the EWSR1 gene with partner genes not from the ETS gene family, tumors with unusual changes in the EWSR1 gene (amplification or deletion), which can cause significant diagnostic difficulties. In this article, we will describe a case of a primary bone tumor with an atypical morphology similar to myoepithelial carcinoma, where an amplification of the EWSR1 gene was detected. According to morphological, immunological, genetic and clinical signs, this tumor was classified as a sarcoma from the EWSR1::non-ETS group of round-cell sarcomas, namely a sarcoma with EWSR1::NFATC2 rearrangement, first formalized in the WHO classification of soft tissue tumors in 2020.

   Early T-cell precursor leukemia (early T-cell precursor, ETP-ALL) is a new subvariant of acute lymphoblastic leukemia (ALL). Tumor blasts have a unique phenotype, including signs of both stem and myeloid cells. This fact significantly complicates differential diagnosis. Cytogenetic and molecular biological features of cells in ETP-ALL are the most important diagnostic criteria. Nowadays the leading scientific international groups of pediatric leukemia conduct researches to develop new treatment protocols for ETP-ALL or to optimize existing chemotherapy regimens by including targeted drugs (bortezomib, ruxolitinib, venetoclax). Currently, hematopoietic stem cell transplantation is a mandatory option in the treatment of ETP-ALL. Targeted drugs and CAR-T-cell (chimeric antigen receptor of T-cells) therapy are the most perspective ways of posable treatment. In this article there are summarized data on diagnosis and therapy and a description of a successful treatment of a patient with ETP-ALL.

   Fanconi anemia (AF) is a hereditary genetic disease characterized by developmental abnormalities, progressive bone marrow failure, hypersensitivity to alkylating agents, and a tendency to hematological and solid tumors throughout life. The only curative option in the treatment of bone marrow failure in patients with AF is allogeneic hematopoietic stem cell transplantation (allo-HSCT). There are no detailed descriptions of allo-HSCT in patients with AF in the Russian-language literature. On the example of a clinical case with AF at the onset of myelodysplastic syndrome, a choose of method for treating bone marrow failure is presented.

   On October 19, 2022, the Council of Experts considered and discussed a number of issues related to the treatment of patients with infantile hemangioma in the Russian Federation.

   The success in pediatric oncology and hematology diseases treatment opened the way to cure more than 90 % of patients with leukemias and lemphomas. The ability to share an achievements in modern paediatric oncology and hematology, to find an actual directions of development, to permit the specialists from every corner of the world to communicate and discuss the most difficult aspects in diagnosis and treatment of paediatric malignancies – the basis of the International Society of Paediatric Oncology (SIOP) work. In the current issue it is presented the thesis of reports of 54th SIOP Congress, which took place in Spain (Barcelona) from September 28 to October 1, 2022. New target drugs (blinatumomab, inotuzumab ozogamicin, dinutuximab, venetoclax, daratumumab, asciminib), cellular (CAR-T) and immune approaches for malignancies treatment, new achievements in supportive care, psychological and social aspects of medical care organization for paediatric patients with malignancies – only a few topics, that were discussed of the event.