Glioma is a common type of primary brain tumor, accounting for about 33% of these tumors. Gliomas originate in the glial cells in the brain. Glial cells are the tissue that surrounds and supports neurons in the brain.
These tumors arise from three different types of cells that are normally found in the brain: astrocytes, oligodendrocytes, and ependymal cells. Gliomas are called intrinsic brain tumors because they reside within the substance of the brain and often intermix with normal brain tissue.
There are different grades of gliomas; however, they are most often referred to as "low-grade" or "high-grade" gliomas. The low or high grade designation reflects the growth potential and aggressiveness of the tumor.
Causes of and risk factors for glioma:
There is no obvious cause of glioma. This type of brain tumor affects all ages, but is more common in adults. Gliomas are slightly more common in men than in women and more common in Caucasian people than in African-American people.