Surgery for mediastinal tumors is still one of the most difficult in modern medicine. This is due to vital organs and various nature of tumors in this area. Teratomas are relatively rare among mediastinal tumors. However, they have certain features that is important for treatment strategy and management of possible complications. This can complicate diagnostic algorithm, exclude transthoracic biopsy and contribute to active surgical approach even for benign process. Oncogenesis of teratoma has its own characteristics. Tissues of different organs are always present in this tumor. Among these, pancreatic tissue inclusions are rare. A few data in the world literature on the treatment of such patients do not allow to develop a universally accepted algorithm of diagnosis and treatment. The authors present two patients with mediastinal teratoma. The second patient had teratoma with pancreatic tissue. The authors discuss the diagnostic algorithm for similar cases. A special attention is paid to description of possible complications throughout long-term follow-up period. Surgical aspects including the choice of access and local spread of process (adhesions in the area of surgical interest) are considered. The report on the treatment of two patients with rare mediastinal tumors containing pancreatic tissue will be useful for primary care physicians, thoracic surgeons, oncologists and morphologists.