Mondo Description A malignant germ cell tumor characterized by the presence of a monotonous primitive germ cell population. The neoplastic cells form aggregates and have an abundant pale cytoplasm and uniform nuclei. The aggregates of the germ cells are separated by fibrous septa which contain inflammatory cells, mostly T-lymphocytes. It arises primarily in the ovaries, but can occur both primarily and secondarily at other sites, particularly the central nervous system. It responds to chemotherapy and radiotherapy. Its prognosis is related to the tumor stage.