Definition

A type of tumor that begins in germ cells (cells that form sperm or eggs). Germinomas can occur in the ovaries or testicles or other parts of the body, but they occur most often in the central nervous system (brain and spinal cord). This happens when a germ cell travels to the brain during fetal development and later becomes a germ cell tumor. Some germinomas make a hormone called beta-human chorionic gonadotropin (beta-HCG). Germinomas are usually malignant (cancer) but tend to grow and spread slowly and can usually be cured. They are the most common type of central nervous system germ cell tumor. They usually occur in teenagers and young adults.