A case of mediastinal teratoma with pancreatic islets accompanied by discontinuation of insulin treatment in insulin-dependent diabetes mellitus

[Surgery for mediastinal teratoma containing pancreatic tissue]

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.

Mediastinal Germ Cell Tumors: A Review and Update on Pathologic, Clinical, and Molecular Features

Mediastinal germ cell tumors (MGCTs) are the most common extragonadal germ cell tumors (GCTs) and most often arise in the anterior mediastinum with a male predilection. MGCTs also have a predilection for patients with Klinefelter syndrome and possibly other genetic conditions. MGCTs, as GCTs at other extragonadal sites, are thought to arise from germ cells improperly retained during migration along the midline during embryogenesis. Similar to their counterparts in the testes, MGCTs are classified into seminomatous and nonseminomatous GCTs. Seminomatous MGCT represents pure seminoma, whereas nonseminomatous MGCTs encompass pure yolk sac tumors, embryonal carcinoma, choriocarcinoma, mature or immature teratoma, and mixed GCTs with any combination of GCT types, including seminoma. Somatic-type or hematologic malignancies can also occur in association with a primary MGCT. MGCTs share molecular findings with GCTs at other sites, most commonly the presence of chromosome 12p gains and isochromosome i(12p). Treatment includes neoadjuvant chemotherapy followed by surgical resection of residual tumor, with the exception of benign teratomas, which require only surgical resection without chemotherapy. In this review, we highlight and provide an update on pathologic, clinical, and molecular features of MGCTs. Immunohistochemical profiles of each tumor type, as well as differential diagnostic considerations, are discussed.