Introduction. Tumor-associated gangliosides are overexpressed on a large number of tumors. The ratio of the amount of gangliosides varies from one type of tumor to another. Tissue restriction of GD2 expression in normal cells and its presence in a wide range of human tumor diseases has increased the relevance of GD2 as a target for immunooncology drugs.

The aim of the study was to improve the efficacy of the treatment of children and adolescents with refractory and recurrent solid malignancies (soft tissue, undifferentiated and bone sarcomas) by incorporating targeted immunotherapeutic options (passive immunotherapy with antiGD2 monoclonal antibodies (MA)) into comprehensive therapy programs.

The primary objective of the study was to analyze the efficacy of tandem use of antiGD2 MA and 2+ line chemotherapy on survival. Secondary targets were overall response rate (complete remission (CR) + partial remission (PR)), tumor control rate (CR + PR + stabilization), duration of response, and immune-associated adverse events.

Materials and methods. The clinical study protocol was initiated at the Petrov National Medical Research Center of Oncology of the Ministry of Health of Russia and approved by the local ethics committee No. 8 of 21.05.2021. On the basis of a signed memorandum of cooperation, the Research Institute of Pediatric Oncology and Hematology named after Academician of the Russian Academy of Medical Sciences L.A. Durnov at N.N. Blokhin National Medical Research Center of Oncology of the Ministry of Health of Russia.

The study is prospective. It is planned to evaluate the efficacy and safety of using antiGD2 MA and 2+ line chemotherapy at the investigator's choice in patients under 18 years of age with bone, soft tissue and undifferentiated sarcomas with positive GD2 expression and disease progression/recurrence on/after the 1st line of polychemotherapy.

This study screened 40 patients to randomize 10 patients. In the future, an additional set of patients is planned.

Conclusion. Based on the results obtained, the efficacy and safety of using a combination of antiGD2 immunotherapy and 2+ line chemotherapy in patients under 18 years of age with refractory and recurrent forms of bone and soft-tissue GD2-positive sarcomas will be concluded.

Introduction. Over the past 10 years, there has been a 130 % increase in the amount of thrombosis in hospitalized children. The data about frequency, outcomes and long-term complications of incidental thrombosis is usually presented together with symptomatic thrombosis, and the problem of asymptomatic thrombosis seems to be underestimated.

Aim to the study – to assess the patient-related characteristics, outcomes of incidental thrombosis in children. To estimate the frequency, severity and risk factors of post-thrombotic syndrome (PTS) after incidental thrombosis. To evaluate the effect of therapy on thrombus resolution and frequency of PTS following asymptomatic deep vein thrombosis (DVT) in children.

Materials and methods. We have retrospectively analyzed the medical records of 48 patients from 0 to 17 years (at the time of thrombosis) from 2013 to 2023 of our tertiary care Centre with objectively confirmed asymptomatic DVT of upper or lower extremity. All patients were divided into 2 groups: patients, who did not receive antithrombotic treatment (G1) and who assessed therapy (G2). Then we analyzed the data of PTS assessment in these patients. PTS was measured using Manco–Jonson Instrument (MJI), Modified Villalta Scale (MVS), the Clinical Assessment of Post-Thrombotic Syndrome (CAPTSure). Chi-square test was used to assess the statistical significance of differences between groups.

Results. 90 % of patients were cancer patients, most of DVTs (96 %) were in the veins of upper extremity, 27 % of thrombosis were occlusive. There were no statistically significant differences between G1 and G2 in thrombus resolution, severity and frequency of PTS. The overall frequency of PTS was 46 % using MVS/MJI and 29 % using CAPTSure. Majority of children had mild PTS, the most common symptom was the presence of collaterals. There was 1 patient with moderate PTS in G2.

Conclusion. The overall frequency of PTS in patients with asymptomatic thrombosis was 46 %. However, most patients had mild PTS and slight clinical sings. There were no statistically significant difference in the rate of recanalization at 3 months after thrombosis between patients who received anticoagulant therapy and those who did not. Also, there were no statistically significant differences in the frequency and severity of PTS between groups.

In ophthalmopediatric practice retinoblastoma (Rb) – is the most common malignant pathology of the eye that occurs as a result of malignant transformation of the embryonic retina. The main clinical manifestations accompanying Rb are leukocoria, strabismus, decreased visual acuity, the presence of yellowish-white foci on the fundus with and without surrounding subretinal fluid, as well as tumor dropouts in the vitreous and/or under the retina. Usually, morphological confirmation of the diagnosis is not required. The main diagnostic instrumental methods for the diagnosis of Rb are biomicroscopy of the anterior segment of the eye, ophthalmoscopy of the fundus with maximum druginduced mydriasis, ultrasound of the eyes and orbits and MRI with contrast enhancement of the orbits and brain. There are a number of diseases that have common clinical signs with Rb, which can be difficult for practicing ophthalmologists to diagnose. An ophthalmologist should always be on-alert and if there are difficulties in diagnosis, the child should be sent to a specialized center.

The article presents a report for 13 months of the work of the Competence center for Retinoblastoma of the Research Institute of Pediatric Oncology and Hematology named after Academician of the Russian Academy of Medical Sciences L.A. Durnov at N.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of Russia on the identification of pseudoretinoblastomas among patients treated with critical symptoms that may accompany or simulate Rb.

Introduction. Patients treated with chemotherapy and hematopoietic stem cell transplantation (HSCT) often suffer from complications that have a negative impact on appetite and the functional ability of the digestive system, which can lead to the malnutrition – a factor of poor overall survival prognosis in hematology. Oral nutritional supplementation is one of the nutrition support (NS) types, which is currently developing by improving the taste properties and optimizing formula chemical composition, but is an underestimated NS option in clinical practice.

The aim of the study – to evaluate oral nutritional supplements (ONS) tolerability and compliance in pediatric oncology patients during anticancer treatment.

Materials and methods. From 2015 to 2022, in the Raisa Gorbacheva Memorial Research Institute of Children Oncology, Hematology and Transplantation, First Pavlov State Medical University of St. Petersburg, Ministry of Health of Russia 988 cases of oral nutritional supplementation in patients from birth to 18 years old, with acute leukemia – 49.5 % (n = 489), hereditary diseases – 17.4 % (n = 172) and solid tumors – 16.9 % (n = 167) were included to a retrospective analysis. The median age was 7 (3–13) years. Male patients were in 61 % of cases (n = 603), female patients – 39 % (n = 385). In 74.2 % of cases (n = 733) allogeneic HSCT was used as a treatment option, in 22.4 % (n = 221) chemotherapy and autologous HSCT, in 3.4 % (n = 34) surgery, 11 of them as a primary tumor removal, 23 as a part of the main treatment’s complications cure. At the time of sipping initiation in 50.7 % of cases (n = 501), there was hyporexia, in 26.8 % of cases (n = 265) maldigestion, in 27.2 % (n = 269) malabsorption. In 54.6 % of cases (n = 203), a chronic graft-versus-host disease (GVHD) was observed, including the mucous membranes and gastrointestinal tract involvement. In 1.8 % of cases (n = 18), ONS was used in combination with breastfeeding, in 2.8 % (n = 28) with enteral nutrition and in 15.1 % (n = 149) with parenteral nutrition. The formula composition included standard (n = 766), semi-elemental (n = 97), balanced infant formula (n = 89) and specialized (n = 36) samples. The sipping usage in the relation of HSCT onset was preventive (n = 130), in the early period – up to D+30 (n = 212), D+31–100 (n = 182), D > +101 (n = 400).

Results. Good ONS tolerability in the general cohort of patients was in 96.1 % (n = 948). Cases of poor tolerance were noted in 3.9 % of patients (n = 38). The factors that matched children with reduced sipping tolerance compared with acceptable one were: age – median 13.5 (4.0; 15.8, Q₁ –Q₃ ) and 7 (3.0; 12.0, Q₁ –Q₃ ) years, p = 0.002; presence of chronic GVHD – 91.3 % (n = 21) and 52 % (n = 181), p = 0.001; unpleasant formula taste – 42.1 % (n = 16) and 12.1 % (n = 115), p < 0.001, respectively. The effectiveness of sipping was evaluated before and after therapy based on the dynamics of body mass index (BMI) in three age groups: 14.5 (13.1; 16, Q₁ –Q₃ ) and 14.5 (13.4; 16.0, Q₁ –Q₃ ) in patients 2–8 years old, p = 0.12; 15.2 (13.7; 17.3, Q₁ –Q₃ ) and 14.7 (13.6 and 16.4, Q₁ –Q₃ ) in patients 9–12 years old, p = 0.009; 17.1 (14.6 and 19.9, Q₁ –Q₃ ) and 16.3 (14.3 and 18.4, Q₁ –Q₃ ) in patients aged 13–18 years, p = 0.0000. These results indicate that oral nutritional supplementation alone or as part of NS allow maintaining BMI within the average age standards, but only in younger patients in comparison with adolescents. In the group of patients with allogeneic HSCT (n = 731) in comparison with the general cohort of patients included in the follow-up, reduced ONS tolerance was determined somewhat more often – in 4.5 % of cases (n = 33). Chronic GVHD (91.3 %, n = 21, p = 0.001) was identified among the factors influencing the risk of developing reduced formula tolerance, while hyporexia (36.4 %, n = 12, p = 0.28), maldigestion (30.3 %, n = 10, p = 0.73) and malabsorption (42.4 %, n = 14, p = 0.1) did not have a negative effect. In 86.7 % of cases, patients characterized the sipping taste like: “I enjoy it”; and in infants, the criterion of adequate compliance was the absence of baby bottle rejection. Among the subjects who used sipping for more than one week with a pleasant taste for them (n = 810), 8.8 % (n = 79) developed formula rejection. In the group of patients with reduced compliance (n = 131) – who initially did not like the ONS taste and texture – an increase in the frequency of poor tolerability was noted from 2.6 to 12.2 % (n = 16), p < 0.001. Combined NS was also more often required: enteral nutrition 1.6 % (n = 14) and 10.7 % (n = 14), parenteral nutrition – 13.2 % (n = 113) and 27.5 % (n = 36), respectively, p < 0.001. Conclusions. Oral nutritional supplementation is an essential part of NS in pediatric oncology and hereditary diseases treatment, including the HSCT, which, on the example of patients with malfunctioned digestive system, has an appropriate tolerance and compliance.

Actuality. In recent years, there have been significant advances in the diagnosis and treatment of malignant tumors in children. An increase in survival and, consequently, a decrease in mortality rates in developed countries of the world is associated not only with improved methods of diagnosis and treatment, but also with timely registration of primary cancer cases. There is significant geographical, gender, age and ethnic variability in the spread of cancer in children in the world. Cancers found in young children often have clinical and biological properties that differ from those of the same histological type of cancer found in older children.

The purpose of the study. To study the aspects of descriptive epidemiology of malignant tumors in young children in the Kyrgyz Republic.

Material and methods. Over 15 years (2008–2022), according to the population registry, 517 cases of cancer were registered in children in the younger age group (0–4 years). Crude and age-standardized rates were calculated using the world standard population, depending on gender, age, ethnic group and region. The data on the average annual number of children in the republic based on the materials of the National Statistical Committee were used.

Results and discussion. By gender, there were 311 (60.1 %) boys and 206 (39.9 %) girls. The sex ratio of boys/girls was 1.51. Leukemia was in the first place in the structure of cancer in young children – 172 (33 %) cases or. Kidney tumors (nephroblastoma) were in second place with a frequency of 77 (15 %) cases. The third one had eye tumors (retinoblastoma) with a frequency of 59 (11 %) cases. The average annual incidence of boys in the urban population was registered at 85.7, and in rural areas – 54.8 per 1 million of the corresponding population (p = 0.023). The incidence among indigenous ethnic groups (kyrgyzs and uzbeks) was recorded at 58.5 and 76.7, respectively. There was a statistically significant increase in the incidence of cancer in children of the Russian ethnic group (121.7) compared with other nationalities. Relatively high levels of morbidity were registered in Bishkek, Jalal-Abad and Issyk-Kul regions.

Conclusion. In the younger age group, the incidence of malignant tumors is higher than in middle and older childhood, but relatively lower than in developed countries. It is necessary to further study the features of the spread of tumors in children in Kyrgyzstan using large groups and analytical methods of epidemiology.

The well-known functions of platelets are participation in the hemostasis system and thrombosis, which, in turn, are performed by their adhesion to damaged tissues, as well as aggregation among themselves with the formation of a hemostatic plug that covers the lesion. The adhesion and aggregation abilities of platelets are determined by their specific membrane glycoproteins.

However, platelet functionality is not limited solely to thrombosis. For example, there is evidence for the use of platelets by tumor cells to effect metastasis. This publication summarizes the international literature on the role of platelets in hematogenous tumor metastasis.

The diagnosis of malignant neoplasms of bones often causes difficulties for doctors of all specialties. Despite the fact that many radiological features of malignant neoplasms have been identified (invasive growth, periosteal reaction, destruction of the cortical layer and the presence of a soft tissue component), instrumental diagnostics is a difficult task in making a correct diagnosis. Morphological investigation is a mandatory method for diagnosis, however, at the same time, some nosological units have a similar morphological picture. The differential diagnosis of teleangiectatic osteosarcoma and aneurysmal bone cyst is a particularly difficult task, because these two neoplasms have not only a similar histological, but also a radiological picture. The mistaken diagnoses delay the correct diagnosis and, accordingly, the start of treatment, that affects the patient’s prognosis.

The purpose of this review is to update information about the epidemiology, clinical-pathogenetic and genetic characteristics, and therapeutic approach to familial inherited erythrocytosis (FIE) in children in the Chuvash Republic.

This review presents updated data indicating that the variant of congenital polycythemia with the VHLR200W (598C>T) mutation in the Chuvash Republic does not have the expected association with tumor predisposition syndrome induced by VHL and does not lead to an increased frequency of their occurrence. Thrombosis largely explains the morbidity and mortality from congenital erythrocytosis, but patients with the Chuvash mutation show a reduced body mass index, systolic blood pressure levels, glucose and HbA1c levels, and leukocyte and platelet counts compared to control groups. A higher hematocrit level is not an independent predictor of thrombotic risk in children and adults. Moreover, prospective randomized studies have demonstrated that phlebotomy, performed to reduce hematocrit levels, is associated with a higher thrombotic risk.

Malignant extrarenal rhabdoid tumor is a rare, highly aggressive neoplasm of childhood, belonging to a group of heterogeneous formations and having an extremely poor prognosis with a median survival of 2–12 months.

In this article, we present a clinical case of a female patient with a malignant extrarenal rhabdoid tumor of the soft tissues of the submandibular region, diagnosed at the age of five months. The child received comprehensive treatment and has been in remission since the age of one and a half years. Due to the prolonged absence of signs of recurrence, continued growth, and progression of the disease, a decision was made on the advisability of conducting a reconstructive plastic stage of treatment to restore the lower zone of the child’s face.

Relevance. Late-onset vitamin K deficiency bleeding is considered a successfully preventable condition, however, current data on morbidity in the group of children who received prophylactic administration of menadion are missing, and the effectiveness of the drug is questionable. At the same time, late diagnosis of this disease often leads to disability and death of patients.

The purpose of the study – to demonstrate the high prevalence of late vitamin K-dependent coagulopathy in a group of healthy full-term infants who received prophylactic administration of menadione sodium bisulfite.

Materials and methods. The retrospective analysis included all children who had an established diagnosis of late-onset vitamin K deficiency bleeding and were treated at the Rostov Regional Children’s Clinical Hospital. All patients underwent an assessment of their medical history and necessary laboratory examinations. The diagnosis was made on the basis of the following criteria: spontaneous bleeding occurring between day 8 and month 6 of life; and characteristic changes in the coagulation parameters, with no evidence of hereditary coagulopathies.

Results. The diagnosis of late-onset vitamin K deficiency bleeding was established in 13 children. 11 of them received prophylactic menadione administration in the hospital. Out of the 8 full-term healthy children who received the prophylaxis, 3 developed spontaneous intracranial hemorrhages and one patient died. In all cases, after the administration of menadione, coagulation parameters returned to normal.

Conclusion. Prophylactic administration of menadione is probably not effective enough in preventing late-onset Vitamin K deficiency bleeding. Further research into the effectiveness of this medication may allow us to revise the current recommendations and lower the incidence of this condition.

Malignant tumors of the scalp are neoplasms of various morphologies. The most common malignant tumors of this localization are basal cell and squamous cell skin cancer, accounting for 95 % of all neoplasms in adults. Malignant tumors of the scalp in children account for no more than 0.2 % of all malignant tumors in childhood, of which unclassified carcinoma accounts for 0.1 %. The etiological factors of unclassified skin carcinoma are unknown, but previous factors include genetic predisposition, hemorrhage after trauma. The specific anatomical structure of the scalp (high density of hair follicles, the presence of hair), as well as the lack of specificity of symptoms and signs, leads to late diagnosis of skin tumors, which affects treatment and prognosis. CT-scan better diagnoses the condition of bone structures, and magnetic resonance imaging better assesses the presence of intracranial spread and the degree of involvement of brain structures. The difficulty of differential diagnosis of rare morphological variants of skin tumors in children lies in the lack of a unified database of rare skin tumors of childhood. To treat patients with malignant tumors of the scalp, combined antitumor treatment is used, including multicomponent chemotherapy, radiation therapy, and modern surgical technologies. Currently, unclassified skin carcinoma remains poorly understood. Therefore, the treatment of this cohort of patients requires a multidisciplinary approach.

The casuistry of benign triton tumor/neuromuscular choristoma (NMC) in the world medical literature has no more than 40–50 observations. There are no descriptions of a such disease in Russian sources. Here is our own case. A 6-year-old boy was diagnosed with a benign tumor of the right sciatic nerve. Sciatic neurolysis and removal of the neoplasm with a size of 8 × 3 × 3 cm were performed. Histological and immunohistochemical investigation revealed a tumor built of bundles of striated muscles and nerve fibers intertwined in the collagen matrix. Conclusion: benign triton tumor (NMC).

NMC is an extremely rare neoplasm associated with large nerves and occurs more often in childhood. Pain syndrome/neuropathy is usually clinically registered. Although a mature triton tumor is considered benign, it often has recurrences and desmoid fibromatosis (mainly postoperative): it is assumed that trauma stimulates fibroblasts/myofibroblasts with a mutation of the CTNNB1 gene. For this reason, noncontact diagnosis is recommended for patients with classic clinical and radiological signs of NMC. To develop an optimal approach to the treatment of this tumor and to assess the long-term prognosis of the disease, it is necessary to accumulate a sufficient number of observations.