Primitive Neuroectodermal Tumors: These are brain tumors that arise from primitive, embryonic cells that migrated to the brain during fetal development and did not mature normally. They are most common in the first decade of life, and are fast growing and highly malignant. The most common type of these tumors occurring in children are medulloblastoma (which strikes the medulla, a section of the brain stem) and neuroblastoma, which grows in the cerebrum. Tumors of the pineal region arising from embryonal tissue are called pineoblastomas.

Tumors of Nerve Cells (neuromas): Acoustic neuroma is the most common neuroma to occur in the brain. It strikes the eighth cranial or acoustic nerve, and usually can be completely removed with surgery. These tumors grow slowly, and are most common in people in their 40s and 50s. Early symptoms include ringing in the ears and dizziness.

Pineal Gland Tumors: The pineal gland is a pinecone-shaped gland located at the base of the brain that secretes melatonin, a hormone involved in regulating circadian rhythms and sleep. Tumors of the pineal gland are more common in children than in adults.

Germ Cell Tumors: These are tumors that arise from testicular or ovarian cells that have migrated to the brain. This migration is believed to occur during fetal development. These cancers are more common in children than in adults. They respond well to chemotherapy. In some cases these tumors can be identified by blood tests, because germ cell tumors produce large amounts of certain chemicals such as alpha fetoprotein and human chorionic gonadotropin.

Pituitary Gland Tumors: The pituitary gland, located at the base of the brain, releases a number of different hormones involved in growth and metabolism. Tumors of this gland, which are called pituitary gland adenomas, are benign and slow growing, and account for 8 percent of all intracranial tumors. They may or may not secrete pituitary hormones.

Meningiomas: These are tumors of the membranes surrounding the spinal cord and brain. They are relatively common, accounting for 20 percent of all brain tumors in adults and a quarter of spinal tumors. Meningiomas occur more frequently in women than in men. Slow-growing meningiomas are the most common type. Surgical removal, if possible, usually cures them. There also are malignant forms. Researchers are investigating a drug called hydroxyurea for treating recurrent forms of this tumor. In cases where meningiomas are growing very slowly, doctors may choose not to treat the patient immediately but instead observe the tumor closely, a strategy known as watchful waiting.