This is a case of mixed germ cell tumor (MGCT) of the mediastinum in a 38 y/o male. MGCTs make up about 15% of mediastinal germ cell tumors in adults. Most patients are male. In adults, the most common components are teratoma and embryonal carcinoma, as was the case here. The image shows islands of hyaline cartilage separated by immature stroma (teratoma component) and scattered tubular-glandular structures that were CD30 positive (embryonal carcinoma component). In children, they usually consist of teratoma (mature and immature) and yolk sac tumor. MGCT of the mediastinum are usually symptomatic. The presenting symptoms include chest pain, cough, dyspnea, hoarseness, superior vena cava syndrome, and cardiac tamponade. They are rapidly growing tumors and frequently invade other mediastinal structures and nearby organs.