A malignant teratoma that involves the mediastinum. The disease is MONDO_0021283 (malignant teratoma of mediastinum). Also known as: immature malignant teratoma of mediastinum, immature malignant teratoma of the mediastinum, malignant mediastinal teratoma, malignant teratoma of the mediastinum, mediastinal immature malignant teratoma, mediastinum malignant teratoma.