Meningiomas are slow-growing tumors that represent about 30 percent of all primary tumors of the central nervous system. About 90 percent are benign.
A meningioma is a brain tumor that grows in the meninges, a thin layer of tissue covering the brain and spinal cord. Some meningiomas contain cysts or calcified mineral deposits, and others contain hundreds of tiny blood vessels. Because meningiomas tend to grow inward, they commonly cause pressure on the brain or spinal cord. Infrequently meningiomas will grow outward, causing the skull to thicken. Meningiomas grow very slowly and may not produce symptoms for many years.
Symptoms vary by location and size of the tumor. They often first appear as headaches and seizures, the result of increased pressure imposed by the growing tumor. Weakness in the arms or legs, or loss of sensation, may occur with spinal cord meningiomas.
Radiation and genetics are known causes of meningiomas.
Most meningiomas occur in adults between the ages of 40 and 60 years. The annual incidence is approximately 2 cases per 100,000 people.
If a patient has symptoms that suggest a meningioma, the patient’s physician will work with a team of specialists to confirm the diagnosis. A specialist will conduct a neurological examination, followed by CT scans and/or an MRI. These tests will help determine the size, location and type of tumor. Skull x-rays may be obtained if the tumor is believed to involve the bone. Diagnostic tests for spinal cord tumors can include a myelogram or an arteriogram, an x-ray of the blood vessels. The diagnosis can be confirmed by a biopsy.
Surgical removal of the tumor is the treatment most often used in patients with meningioma. Aggressive surgery may include removal of part of the meninges and any abnormality in the bone as well as the tumor.
Sometimes, only part of the tumor will be removed because of its location near sensitive areas of the brain. This partial removal can still relieve symptoms, and further surgery may not be needed because of the availability of other effective treatments. Radiation therapy may be used on the remaining tumor cells.
Because meningiomas grow slowly, monitoring a meningioma in an elderly patient may be preferable to surgical removal of the tumor. The physician will monitor the tumor’s growth with frequent MRI scans. Patients should report any symptomatic change immediately.