Glioma is a term used to describe a group of tumors that start in glial cells in the brain. These cells support the function of the other main brain cell type, the neuron. Gliomas often happen in the cerebral hemispheres of the brain. These are the largest, outermost part of the brain that controls many functions, including movement, speech, thinking, and emotions.
But gliomas can also first appear in the brain stem. The brainstem is the lower part of the brain that controls breathing, blood pressure, and heartbeat. Gliomas can also first appear in the optic nerves and cerebellum. The cerebellum is the part of the brain that deals with balance and other non-thinking functions.
Gliomas can be cancerous (malignant) or non-cancerous (benign). They make up about 3 in 10 of all tumors that start in the brain.
Gliomas come in several types. The category that a glioma falls into depends on the type of glial cell it comes from. These are types of gliomas:
- Astrocytoma. This type of glioma is a tumor that comes from astrocytes, the star-shaped glial cells in the brain. The fastest growing astrocytomas are called glioblastomas.
- Oligodendroglioma. These gliomas come from oligodendrocytes. These are glial cells that normally form a cover for nerve fibers in the brain.
- Oligoastrocytoma. These gliomas are a mix of abnormal oligodendrocytes and astrocytes.
- Ependymoma. This type of glioma comes from the cells lining the cavities of the brain and spinal canal. They are most common in children.
- Ganglioglioma. This is a rare glioma that can occur in the brain or spine. It forms from both glial cells and nerve cells.