Ewing sarcoma is a relatively rare aggressive tumor of bones and soft tissues characterized by specific chromosomal translocations involving genes and transcription factors of the FET and ETS families. A number of studies have demonstrated the presence of molecular genetic events preceding these specific rearrangements.
The article presents a clinical observation of the treatment of a 24-year-old patient with Ewing sarcoma of the X rib and CHEK2-associated cancer predisposition syndrome with an oncologically burdened family history, including Ewing sarcoma in a first-degree relative. Specific translocation of the EWSR1 gene (22q12) was identified, characteristic of tumors of the Ewing sarcoma/PNET (primitive neuroectodermal tumors) family, as well as 59 variants of different functional significance in suppressor genes and driver genes was identified in the course of a comprehensive molecular genetic study using fluorescence in situ hybridization (FISH) and next-generation sequencing (NGS) with a targeted custom panel including 415 genes involved in carcinogenesis. The patient underwent combined treatment in the volume of neoadjuvant polychemotherapy, surgical stage (extirpation of the X rib with plastic surgery) and subsequent adjuvant polychemotherapy. During dynamic observation for the period 2022–2025, there were no signs of progression and metastatic process. 
Molecular genetic profiling in Ewing sarcoma has identified markers that may act as risk modifiers for disease development and progression, determine sensitivity/resistance to standard treatment methods, and serve as potential targets for personalized treatment.

Introduction. Osteoblastoma is a locally aggressive benign tumor affecting skeletal bones and most commonly seen in the spine. Most complications arise during treatment of stage III osteoblastoma per the Enneking classification characterized by fast growth and intra- or extracompartmental lesions. Despite the use of modern navigation technologies, intraoperative orientation of a surgeon relative to the soft and bone tissues remains the most important factor of successful and complete resection of the pathological lesion in case of osteoblastoma. The use of denosumab as a neoadjuvant agent promotes sharper differentiation of the tumor from intact bone tissue which makes tumor resection easier. Additionally, this drug can be used in the postoperative period to decrease the risk of recurrence and for unresectable forms of the tumor. 
Aim. To evaluate the effectiveness of denosumab in the treatment of aggressive  spinal osteoblastoma.
Materials and methods. The results of treatment of 6 patients (5 men, 1 woman) with aggressive stage III osteoblastoma per the Enneking classification who received treatment at the 11th Division of the National Medical Research Center of Traumatology and Orthopedics named after N.N. Priorov between 2021 2025 were analyzed. In all cases, diagnosis was histologically confirmed at the biopsy stage. Tumors were located at different levels of the spine: in 2 cases, in the cervical spine; in 3 cases, in the thoracic spine; and in 1 case, in the sacrum. All patients were prescribed denosumab (off-label). Density and volume of the tumor was evaluated using computed tomography and Gamma Multivox software.
Results. Analysis of the main effectiveness endpoints showed that the use of denosumab is associated with increased tumor density and significant decrease of pain in all patients. Additionally, a trend towards increased tumor volume per computed tomography was observed which can be explained by improved visualization of the tumor margins due to sclerotization of the soft-tissue component.
Conclusion. Neoadjuvant therapy with denosumab showed its effectiveness in aggressive osteoblastomas which opens new options for treatment of unresectable and recurrent tumors.

Introduction. The incidence of bone sarcomas in the distal tibia is about 5 %. Considering the features of this anatomical area, for a long time amputation was considered the method of choice for local control of the disease. Development of ankle joint endoprostheses in the 1970’s allowed to perform organ-saving surgeries. Data on the effectiveness of this technique in children and teenagers is very sparse and are usually presented as individual observations from large samples.
Aim. To evaluate oncological and functional outcomes of endoprosthesis of the distal tibia and ankle joint with personalized implants in children and teenagers with bone sarcomas and to describe complications (per the Henderson classification) of this surgical intervention.
Materials and methods. The study included 21 patients with ages varying between 8 and 17 years (median age 13.8  ±  3.2 years). All patients received combination treatment. Endoprosthesis of the distal tibia and ankle joint was performed. Functional results were evaluated after 12 months using the Musculoskeletal Tumor Society Score (MSTS) scale. Oncological outcomes were analyzed using the Kaplan–Meier method. All complications were classified per the Henderson system modified by the International Society of Limb Salvage (ISOLS).
Results. In 13 (61.9 %) cases, resection of both tibia and fibula was performed, in all other cases fibula was saved. Median resection length was 15 (8–22.5) cm. Histological examination verified osteosarcoma in the majority of patients, ratio between this pathology and other malignant neoplasms was 2.5:1. Even-free survival in patients with osteosarcoma of the distal tibia was 53 ± 14 %, overall survival was 77 ± 15 %. Functional results were evaluated in 14 patients. Mean score per the MSTS scale was 72 (49–88) %. Complications were reported in 7 (33.3 %) patients.
Conclusion. The data demonstrated effectiveness of endoprosthesis of the distal tibia and ankle joint in children and teenagers with bone sarcomas; good oncological and functional results were achieved.

Introduction. Pelvic bone metastases are a common complication of malignant tumors, leading to pain, pathological fractures, and decreased quality of life. Surgical treatment plays a key role in palliative care, but the optimal approaches remain controversial.
Aim. To evaluate the results of surgical treatment of patients with pelvic bone metastases, including oncologic and functional outcomes, as well as complication rates.
Materials and methods. A retrospective analysis of 39 patients (21 men, 18 women; median age 55 years) who underwent surgical treatment for metastatic pelvic bone lesions in the period 2002–2022 was performed. The most common localizations were the ilium (10 (25.6 %) cases) and sacrum (13 (33.3 %) cases). A solitary lesion was detected in 33 (84.6 %) patients and multiple bone lesions in 6 (5.4 %) patients. The primary lesion in most cases (in 19 (48.7 %) patients) was kidney cancer. Radical (wide resections) (71.8 % cases) and palliative (decompression and excohleations) (23.1 % cases) methods were used. Survival, complications (according to the Clavien–Dindo classification), pain dynamics (according to the visual analog and Watkins scales) and functional status (according to the Karnofsky scale) were assessed.
Results. Complications developed in 28.2 % of patients, mainly after resections involving the acetabulum (p = 0.029). 
The leading complications were deep infections (8 cases), superficial necrosis (3 cases), which required additional surgical interventions. The median overall survival was 45 months, with solitary metastases – 93 months, with multiple metastases – 20 months (p = 0.019). Intralesional resections were associated with worse survival (p = 0.028). A significant decrease in pain (from 5 to 2 according to the visual analog scale; p <0.001) and improvement in functional status (according to the Karnofsky scale; p = 0.022) were noted. 
Conclusion. Radical resections provide better survival in solitary metastases group, while palliative methods are appropriate for multiple lesions. The choice of tactics requires a multidisciplinary approach, taking into account the prognosis and extent of the lesion.

Introduction. A dermoid cyst of the mediastinum is a rare benign tumor that develops from embryonic tissues as a result of dysembryogenesis.
Aim. To present the experience of surgical treatment of mediastinal dermoid cysts.
Materials and methods. A retrospective analysis of the treatment of 16 patients after removal of a mediastinal dermoid cyst was performed. Gender and age, clinical symptoms, tumor size and location, surgical approach and duration of surgery, volume of blood loss, pain syndrome, duration of drainage and hospitalization, postoperative complications according to the Clavien–Dindo classification were assessed.
Results. The study included 6 (37.5 %) men and 10 (62.5 %) women aged 11 months to 61 years (average age 33.2 years).
Among the patients, 62.5 % were asymptomatic, the rest complained of shortness of breath, cough, discomfort and retrosternal pain. The tumor size ranged from 4.5 to 18.2 cm. The tumor was detected in the anterior-superior zone of the mediastinum in 13 (81.25 %) cases, in the posteroinferior zone – in 3 (18.75 %). Open access was used in 7 (43.75 %) cases, thoracoscopic – in 8 (50 %). In 1 case, conversion to sternotomy was performed. The lung was resected in 3 patients, the thymus gland – in 6, the left brachiocephalic vein and pericardium in 1 case each, of which 5 were resected using the thoracoscopic approach. During thoracoscopy, the volume of blood loss (12.5 (5; 65) and 100 (60; 125) ml, respectively) and the duration of surgery (72.5 (45; 155) and 141.5 (105; 154) min, respectively) were significantly lower than with open access.Pleural drainage was removed on days 1–3 after surgery. Quantitative indicators are presented as a median (25th percentile; 75th percentile). After open approaches, pain was 4–6 points on the visual analogue scale, decreasing to 2–3 points by the end of hospitalization, after thoracoscopic ones – no more than 4 points and stopped after drainage removal. Postoperative complications of I–II degree were in 3 (18.75 %) patients after open operations. Hospitalization after thoracoscopy was significantly shorter and amounted to 5.5 (5; 6.5) bed-days, with open ones – 12 (7.5; 14). There were no fatal cases. No tumor recurrences were noted in the late period.
Conclusion. The absence of specific diagnostic criteria and the presence of contraindications for transthoracic puncture biopsy of the mediastinal dermoid cyst prevent preoperative verification. The surgical method is the only effective option with a favorable prognosis. and thoracoscopic intervention reduces blood loss and hospitalization time.

Cardiac sarcomas are rare primary malignant tumors of the heart. This pathology is predominantly observed in young working-age patients between the ages of 30 and 50 and is characterized by quick progression, aggressive growth, frequent metastasis prior to detection of the primary lesion in the heart, similar symptoms to other heart diseases including heart failure, arrythmia, etc. The article presents the history of cardio-oncology, epidemiologic data and classification of cardiac sarcomas.

Synovial sarcoma is a rare malignant soft tissue tumor characterized by high aggressiveness and a propensity for metastasis. The assessment of therapeutic pathomorphosis plays a crucial role in predicting disease outcomes and selecting the optimal treatment strategy. This article discusses the morphological and molecular characteristics of synovial sarcoma, existing classifications of pathomorphosis, modern assessment methods, and the prognostic significance of pathomorphosis degree. 
Special attention is given to the impact of various factors on treatment efficacy, the prospects of personalized medicine, and the integration of innovative technologies in the diagnosis and management of this tumor.

Introduction. Cutaneous melanoma is one of the most aggressive oncological neoplasms requiring radical surgical treatment with compulsory wide resection of the primary tumor. The problem of restoration of anatomical integrity and functionality of the tissues after tumor resection is very important for favorable prognosis and high quality of life of the patients. Efficacy of the current techniques of reconstruction using local tissues depends on the size and location of the defect.
Aim. To compare short-term results of different types of defect reconstruction using local tissues after wide resection of cutaneous melanoma of the trunk and limbs.
Materials and methods. Prospective analysis of radical surgical treatment of 62 patients with cutaneous melanoma of the trunk and limbs of localized stages (сT1–4N0M0, Eastern Cooperative Oncology Group (ECOG) score 0–1) who at the 1st stage of treatment underwent wide tumor resection with subsequent reconstruction using local tissues was performed. Median age was 61 years (±8.5 years). The study included 33 (53.2 %) women and 29 (46.8%) men. Radical surgical resection included wide melanoma resection aimed to prevent tumor cell dissemination and achieve negative resection margins. The reconstruction stage included 2 main approaches: defect reconstruction using local advancement flaps (38 (61.3 %) cases) and mobilization of the skin margins (24 (38.7 %) cases). Selection of plastic surgery technique depended on tumor location, defect size after its resection, and individual anatomical features of the patient. 
The surgeries were primarily performed on the trunk (30 (48.4 %) cases) and limbs (32 (51.6 %) cases). During surgical intervention, special attention was paid to preservation of cutaneous flap blood flow and minimization of trauma to the surrounding wound tissues.
Results. In the postoperative period, analysis of complications on days 3, 7, 14 and 30 after surgical intervention was performed. Overall complication rate was 16.1 % (n = 10). Adverse events after surgeries on the trunk were significantly rarer (2 (3.2 %) cases) than after surgeries on the limbs (8 (12.9 %) cases). In the local advancement flap group, complications were observed in 4 (10.5 %) cases, primarily in cases of tumors located on the limbs (3 (7.9 %) cases). For trunk location of the tumor, adverse events were observed in only 1 (2.6 %) patient. The main complications were clinically significant seroma, wound margin diastasis, and wound abscess. In the skin margin mobilization group, the incidence of adverse events was 2.5 times higher than in the local advancement flap group (6 (25 %) cases); they primarily occurred in cases of tumors located on the limbs (5 (20.8 %) cases). The most common complications were necrosis of the skin margins and wound abscess. Despite the development of adverse events, in the majority of cases (in more than 75 % of patients) standard time of wound healing (days 14–21) was achieved. Patients with complications received conservative treatment. This allowed to avoid serious consequences but increased healing time which could delay the start of necessary adjuvant drug therapy. These results demonstrate that in surgical treatment of cutaneous melanoma, the selection of defect reconstruction technique and surgical area significantly affects the rate of postoperative complications and their type.
Conclusion. In skin defect reconstruction using local advancement flaps after wide resection of cutaneous melanoma of the trunk and limbs, postoperative complications are 2.5 times rarer than in mobilization of skin margins, especially in cases of defect repair on the limbs. Selection of plastic surgery technique must be made individually taking into account tumor location and size of the defect after tumor resection.

The article describes combination treatment of pleiomorphic sarcoma of the soft tissues of the right shoulder with metastases in the lungs and adrenal glands. This clinical case demonstrates the importance of using combination approach including surgical resection of the primary tumor and its metastases.