A malignant teratoma that involves the testis. The disease is malignant teratoma of testis (MONDO_0021282, a Monarch Disease Ontology id). Also known as: immature teratoma of testis, immature teratoma of the testis, immature testicular teratoma, malignant teratoma of the testis, malignant testicular teratoma, testicular immature teratoma, testicular malignant teratoma, testis malignant teratoma.