The National Cancer Institute reports that more than 35,000 people each year in the United States are diagnosed with a primary brain tumor, meaning a tumor that originated in the brain. There are three major parts of the brain which control different actions, thoughts and perceptions: the cerebellum, the brain stem and the cerebrum. The region in which a brain tumor grows dictates the signs and symptoms caused by the tumor. There are several different types of brain tumors, both cancerous and noncancerous.
Glioblastoma
Merck Manuals, an online medical library, reports that the most common type of brain tumor is a glioblastoma, accounting for 40 percent of all primary brain tumors. A glioblastoma is a tumor that originates from cells that ultimately develop into glial cells. Glial cells surround and hold nerve cells in the brain and spinal cord, according to the National Cancer Institute. Glioblastomas are generally quite fast-growing cancerous tumors. Merck Manuals notes that glioblastomas usually develop in adults.
Meningioma
Merck Manuals reports that a meningioma is a type of noncancerous tumor that begins in the tissue that covers the brain, called the meninges. This is a common type of brain tumor, accounting for 20 percent of all brain tumors. The University of Alabama Health System adds that this type of brain tumor is often very slow-growing, and commonly develops in people in their 40s and 50s.
Medulloblastoma
This type of cancerous brain tumor begins in the cerebellum embryonic cells, and makes up 25 percent of all brain tumor cases. Medulloblastomas most often grow in children. According to the National Cancer Institute, these types of tumors are fast-growing and often spread to the spinal cord.
Oligodendroglioma
An oligodendroma is a type glioma, a type of tumor that begins in mature glial cells. Merck Manuals notes that this type of tumor makes up for five to 10 percent of brain tumors, and affects both children and adults.
Adenoma
The majority of adenomas are noncancerous, and account for approximately 10 percent of all brain tumors, according to Merck Manuals. Adenomas mostly occur in adults.
Less Common Tumor Types
Merck Manuals describes less common types of brain tumors which account for less than 2 percent of the total cases: astrocytoma, a type of cancerous or noncancerous glioma; chordoma, a noncancerous but invasive tumor of the embryonic cells in the spine; craniopharyngiomas, mostly noncancerous tumors of the pituitary gland embryonic cells; dermoid cysts, noncancerous tumors of the embryonic skin cells; ependymomas, mostly noncancerous tumors of the cells that line brain ventricles; and hemangioblastomas, noncancerous tumors of the embryonic cells which differentiate into blood vessels. Many of these tumors develop from embryonic cells that ultimately develop into the cells of mature tissues in the brain.
