Meningiomas are often benign tumors arising from the coverings of the brain and spinal cord. They represent about one-third of all primary brain tumors and occur most frequently in middle-aged women.
Although meningiomas are referred to as brain tumors, they do not grow from brain tissue. They arise from the meninges, which are three thin layers of tissue covering the brain and spinal cord. These tumors are most often found near the top and the outer curve of the brain. Tumors may also form at the base of the skull.
Meningiomas usually grow inward, causing pressure on the brain or spinal cord. They also can grow outward toward the skull, causing it to thicken. Most meningiomas are noncancerous, slow-growing tumors. Some contain sacs of fluid (cysts), mineral deposits (calcifications), or tightly packed bunches of blood vessels.
Meningiomas usually grow slowly, and may reach a large size before interfering with the normal functions of the brain. The resulting symptoms depend on the location of the tumor within the brain. Headache and weakness in an arm or leg are the most common symptoms. However, seizures, personality changes, and/or visual problems may also occur.
Meningiomas account for about 20% of all primary brain tumors, which are tumors that form in the brain or its coverings. They are most likely to be found in adults older than 60; the incidence appears to increase with age. Rarely are meningiomas found in children. They occur about twice as often in women as in men.
Researchers are studying meningiomas carefully to find out what causes them. Between 40% and 80% of meningiomas contain an abnormal chromosome 22. The cause of this abnormality is not known. We do know, however, that this chromosome is normally involved in suppressing tumor growth. Meningiomas also frequently have extra copies of the platelet-derived growth factor (PDGFR) and epidermal growth factor receptors (EGFR), which may contribute to the growth of these tumors.
Previous radiation to the head, a history of breast cancer, or neurofibromatosis type 2 may be risk factors for developing meningioma. Multiple meningiomas occur in 5% to 15% of patients, particularly those with neurofibromatosis type 2.
Some meningiomas have receptors that interact with hormones, including progesterone, androgen, and less commonly, estrogen. Although the exact role of hormones in the growth of meningiomas has not been determined, researchers have observed that meningiomas occasionally grow faster during pregnancy.
Surgery and radiation are the most common forms of treatment for meningioma. Surgery is the primary treatment for meningiomas, although some tumors may not be removed this way. Radiation therapy may be used to tumors that cannot be removed with surgery, tumors that are not completely removed in surgery, malignant/anaplastic tumors, or recurrent tumors.
Careful observation is sometimes the best course of action for patients with meningioma. Scans are performed at regular intervals during this time, and any new or unusual symptoms should be reported to your doctor right away.
Learn more about different treatment options for brain tumors on our Treatment page.
Some meningioma treatments are available through research studies called clinical trials. Click here to access TrialConnect®, the ABTA's clinical trial match service.