Epithelioid hemangioendothelioma of the azygos vein

Background. Epithelioid hemangioendothelioma (EHE) is a malignant vascular tumor of mesenchymal origin. In the mediastinum, EHE originates from the large venous vessels of the superior vena cava. the purpose of the study was to describe a rare clinical case of EHE of the unpaired vein and analyze literature data to improve diagnosis and treatment of this disease. Case presentation. We present a rare case of EHE of the unpaired vein in a 23-year-old male patient who admitted to the Herzen Moscow Oncology Research Institute with a posterior mediastinal tumor detected in August 2022. It was known from the medical history that the patient had undergone diagnostic right-sided thoracotomy and tumor biopsy at the place of residence. Morphologically, the tumor was an epithelioid hemangioendothelioma. The histological re-assessment of biopsy specimens at the Herzen Moscow Oncology Research Institute confirmed the diagnosis of EHE. Computed tomography of the chest organs revealed a mass in the posterior mediastinum (in the projection of the lumen of the unpaired vein), measuring 16×14×41 mm, with relatively clear even contours, close to the posterior wall of the trachea at the bifurcation level, the posterior wall of the right main bronchus, the left semicircle of the esophagus (without signs of invasion). Based on the data on the presence of a vascular tumor in the posterior mediastinum on the right, a multidisciplinary medical consilium recommended surgical treatment: right thoracotomy, removal of a posterior mediastinal tumor with resection of the azygos vein, marginal resection of the superior vena cava, and thrombectomy from its lumen. The duration of surgery was 180 minutes, blood loss was 200 ml. Morphological examination confirmed EHE of the unpaired vein. No complications were observed in the postoperative period. The patient was discharged from the hospital on the 8 th day after surgery in a satisfactory condition.