Background. Tumors of the central nervous system occupy the first place in the structure of causes of death from malignant tumors among children. The tumors of brain stem structures account for 10 to 15% of all intracranial neoplasms in this age group. The etiology of these tumors is not completely known. Diagnosis of pathology is based on clinical manifestations and magnetic resonance imaging. Obtaining material for histological examination at this location is associated with the risk of severe neurological disorders. Despite clinical trials in search of targeted therapy, the treatment of this pathology is based on chemoradiation therapy. Purpose – to analyze the effectiveness of radiation therapy in mono-mode and in patients with the tumors of brain stem structures without intake of Temozolomide, a ccording to the results of clinical studies conducted on the basis of National Children’s Specialized Hospital «OKHMATDYT» of the Ministry of Health of Ukraine. Materials and Methods. On the basis of the National Children’s Specialized Hospital «OKHMATDYT» of the Ministry of Health of Ukraine, in the Department of Radiation Therapy of the Radiology Center during the 3-year existence, 22 people with brain stem tumor were treated on a linear electron accelerator Elekta Sinergy S. By gender: 12 boys aged 3–10 (54%), 10 girls aged 3–11 (46%). The average life expectancy of girls was longer and exceeded one year, compared with boys. The average age was 6 ± 4 years. The diagnosis in most cases was made radiologically, but 4 patients (18%) had histological confirmation. Radiation therapy was performed according to the High grade glioma protocol with total basic dose (TBD) of up to 54 Gy for 30 fractions. 2 patients received repeated radiation therapy due to the deterioration of neurological symptoms and negative dynamics on MRI. Planning of 3D-CRT, IMRT, VMAT irradiation techniques was performed on a Monaco planning system using the Monte Carlo calculation algorithm. Results. The use of radiation therapy with appropriate anti-edematous drug support, provided significant improvement in the neurological status of the child in 5–14 days from the beginning. After 4–6 weeks of control in 21 patients there was a decrease in the pathological focus compared to the original size by 17–70%. In 5 patients the tumor spread to the large hemispheres and/ or spinal cord after radiation therapy. 2 patients received repeated radiation therapy in 1 year and 1 year and 1 month after the previous one, based on the deterioration of neurological symptoms and negative dynamics on MRI. The average life expectancy was 13 months ± 7 months. It was longer for girls – more than a year, compared to boys. Conclusions. Diffuse intrinsic pontine gliomas are the leading cause of child mortality among patients with CNS tumors. Less than 10% of children live more than 2 years after diagnosis. At present, there is no method of radical treatment of patients with diffuse intrinsic point glioma. Radiation therapy still remains the main standard of treatment for DIPG, which improves the quality and duration of a child’s life.

Lymphatic malformations (LMs) - are congenital vascular malformations caused by abnormal embryologic development of the lymphatic system with variable clinical manifestation. Abdominal LMs account approximately 5% of all LMs. The main treatment option for abdominal LMs is surgical. Purpose - to analyze our experience in intestinal and omental LMs diagnosis and treatment, to reveal factors that could influence the complications occurrence risks, that could improve abdominal LMs treatment results in children. Materials and methods. Among 240 pediatric patients, who underwent cystic LMs treatment in a period from December 2012 to July 2022, 43 (19.1%) were diagnosed abdominal and retroperitoneal LMs. 18 (41.8%) patients with intestinal and mesentery affection were included into the study group. Median follow up was 20.7 (95% CI: 12-27) months. Results. Male patients predominated in the study group. Median age at admission was 2.5 (95% CI: 0.75-5) years. 12 (66.6%) had an emergency admission. In 7 (38.8%) children LMs were complicated by intestinal obstruction (n=5; 71.4%), intracystic bleeding and LM cyst infection were observed in n=1, 14.3%) cases both. Surgical treatment was applied in 16 (88.8%) patients, among which 7 (43.7%) underwent laparoscopy. In 4 (25%) cases conversion to laparotomy took place, 5 (31.3%) underwent laparotomic surgeries. No recurrences after surgical treatment were observed. Systemic therapy with mTOR-inhibitors was prescribed in a child with symptomatic total mesentery affection, observational tactics was chosen for asymptomatic child. Conclusions. Intestinal and mesenterial LMs can be asymptomatic or manifest complications, which were observed in 7 (38.8%) children of our group. Macrocystic intestinal LMs are of higher risks of complications development (р=0.0236). Surgical treatment is effective for local intestinal and mesentery affection, excellent treatment result was achieved in 94.1% of patients. In cases with total mesentery affection mTOR-inhibitors systemic therapy is the treatment of choice. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.