Medulloblastomas account for about 25% of all brain tumors in children, and are the most common malignant brain tumor in children, but are relatively rare in adults. These tumors form in the neuroectodermal cells (very young nervous system cells) in the cerebellum and are located in the posterior part of the brain. These tumors are usually very aggressive and can spread throughout the brain and spinal fluid. Doctors commonly treat these tumors with a combination of surgery, chemotherapy, and radiation (including radiation to the spinal cord). Children over 3 years of age, children who have localized disease and children who have had a robust resection of the tumor (standard risk) carry a good prognosis with a 5 year survival rate of nearly 85%. Younger children under 3 years of age are often treated with radiation avoiding strategy using high-dose chemotherapy for better penetration of the blood-brain barrier. Tumors in these younger children fare badly compared to older children who belong to the standard risk. Currently these tumors are molecularly classified into four subgroups: WNT, SHH, Group 3, and Group 4. These subgroups are named for the signaling pathways that are thought to play a role in development of the tumor, and each subgroup carries a different prognosis. The WNT pathway tumors do well whereas the Group 3 and 4 do poorly. New strategies are now being designed to evaluate these subgroups and profile new targeted therapies.

Pineoblastoma is a type of fast-growing medulloblastoma that forms in the pineal gland and is usually malignant. These tumors are treated in a similar way as medulloblastoma; however, they are more difficult to treat and have a worse prognosis than most medulloblastomas.

Craniopharyngiomas are benign brain tumors that do not spread to other parts of the brain or to other parts of the body. They are found near the pituitary gland (organ at the bottom of the brain) and the hypothalamus (organ connected to the pituitary gland). These tumors can press on vital structures such as the pituitary gland, hypothalamus, and optic nerve. These tumors can cause hormone and vision problems, and are difficult to remove without further damaging these structures. Tests that examine the brain, vision, and hormone levels are typically used to detect childhood craniopharyngiomas. Both surgery and radiation are a part of treatment.

Germ cell tumors are rare tumors that form from germ cells, which usually develop into eggs in women or sperm in men. Normally, germ cells travel to the ovaries or testes before birth, during the development of the fetus. Sometimes, these germ cells do not travel to the reproductive organs and may end up in the brain, where they may become malignant and form a brain tumor. There are two different types of germ cell tumors known as germinomas and nongerminomas. These tumors are most common in children, and usually start in the pineal gland and/or above the pituitary gland, and can spread into the spinal cord. Symptoms depend on where the tumor forms, the size of the tumor, and whether the tumor makes hormones. Symptoms may include any of the following: headaches, vomiting, unusual thirst, frequent urination, early puberty, behavioral changes, visual changes, hormonal imbalances presenting as diabetes, and poor school performance. These tumors are treated with a combination of surgery, chemotherapy, and radiation therapy.