What is a mediastinal germ cell tumor?
Mediastinal germ cell tumors are a heterogeneous group of benign and malignant neoplasms that originate from primitive germ cells that remain in the mediastinum after early embryogenesis. The anterior mediastinum is the most common extragonadal primary site of germ cell tumors. Mediastinal germ cell tumors usually occur in young adults. Although mature teratomas occur equally in men and women, most malignant germ cell tumors occur in men. α-fetoprotein and β-human chorionic gonadotropin serum levels may be abnormally elevated in patients with malignant mediastinal germ cell tumors. Primary testicular or ovarian germ cell tumors need to be excluded when a mediastinal germ cell tumor is discovered because the mediastinum may be a site of metastasis from gonadal germ cell tumors.