Sometimes immature teratomas, dysgerminomas, yolk sac tumors, and mixed germ cell tumors (cancer) occur. (See the PDQ summary on Ovarian Germ Cell Tumors Treatment for more information.)Extragonadal Extracranial Germ Cell TumorsExtragonadal extracranial germ cell tumors form in areas other than the brain, testicles, or ovaries.Most extragonadal extracranial germ cell tumors form along the