MONDO_0006298 (mediastinal malignant germ cell tumor) is an extragonadal malignant germ cell tumor that arises from the mediastinum. This category includes seminoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma, mixed germ cell tumors, and immature malignant teratoma. Also known as: malignant mediastinal germ cell tumor, malignant mediastinal germ cell tumour, mediastinal germ cell tumor, malignant, thymic malignant germ cell tumor, thymic malignant germ cell tumour.