A glioma, so named because it originates from glial cells, forms in the brain or spine (usually the brain).
There are four common types of gliomas:
Ependymomas: Forms in the epithelial membrane lining the ventricular system of the brain and spinal cord.
Astrocytomas: Formed in the star-shaped glial cells in the brain and spinal cord, which, among other functions, play a vital role in the repair and scarring process of the brain and spinal cord following a traumatic injury.
Oligodendrogliomas: Forms in the oligodendrocytes, which, among other important functions, helps to insulate the axons (long projection of nerve cells) in the central nervous system.
Mixed gliomas: These tumors form in the glial cells which are partially responsible for insulating and regulating the activity of the central nervous system. One of the most common mixed gliomas is the oligoastrocytoma,which is responsible for approximately 2.3 % of all brain tumors diagnosed.
Signs & Symptoms
The symptoms depend on which part of the central nervous system is affected. A glioma in the brain can cause headaches, nausea, vomiting, seizures, and possibly cranial nerve disorders because of the buildup of cranial pressure. A glioma in the optic nerve can cause blurred vision.
A glioma in the spine can cause pain, weakness, or numbness in the body’s extremities. As opposed to other types of tumors, gliomas do not metastasize, or spread, via bloodstream, but via cerebrospinal fluid instead.
Diagnosis & Treatment
Diagnosing a glioma usually involves a neurological exam (which tests vision, balance, hearing, coordination, reflexes, and the ability to think and remember), scans of the brain (which may include a CT or CAT scan, or magnetic resonance imaging that takes detailed pictures of the brain), and possibly an eye exam to check for swelling caused by pressure on the optic nerve. A biopsy, when a small piece of tissue is cut away from the mass and examined under a microscope, provides the most definitive diagnosis for a glioma.
Treatment depends on the size, location, and grade of the tumor. A glioma in the brain may be treated much differently than a mass on the spine. A glioma in the brain is usually treated with a combination of chemotherapy, radiation, and surgery; the radiation is usually a type of external beam radiation or an approach called radiosurgery. Tumors on the spinal cord are usually treated with surgery and radiation.
Patients with gliomas generally receive a grim prognosis, as these masses are treatable but rarely curable. High-grade gliomas are particularly aggressive. Approximately 10,000 Americans are diagnosed with gliomas each year; roughly half are alive 1 year after diagnosis, 25% after two years. Patients with low-grade tumors have a slightly better prognosis, with some patients surviving up to 11 years, on average, after diagnosis.