Mediastinal Germ Cell Tumor with Somatic-Type Malignancy

**Semantic type:** Neoplastic Process

**Definition:** A rare extragonadal germ cell tumor that arises from the mediastinum and is associated with the presence of a somatic-type malignant component. The somatic malignancy is usually a sarcoma (e.g., embryonal rhabdomyosarcoma, angiosarcoma, or leiomyosarcoma), adenocarcinoma, squamous cell carcinoma, adenosquamous carcinoma, or primitive neuroectodermal tumor. The prognosis is poor.