Meningiomas are brain tumors that develop from the membrane (the “meninges”) that covers the brain and spinal cord. They are the most common primary brain tumor in adults. Most meningiomas (85-90 percent) are categorized as benign tumors, with the remaining 10-15 percent being atypical or malignant (cancerous).
The word “benign” can be misleading for meningiomas. Depending on location and growth rate, benign meningiomas may impinge on vital nerves or compress the brain, causing disability. They may even become life threatening.
Meningiomas occur most commonly in people aged 40 to 70 years and occur more commonly in women. They are found in about 3 percent of people over age 60. The few known predisposing factors are prior radiation exposure, prolonged hormone use, and genetically inherited conditions such as neurofibromatosis type 2.
Meningiomas are most commonly divided into three grades, with 15 histopathologic subtypes based on the individual tumor appearance. Traditionally, one of the most important feature in determining meningioma grade, and therefore behavior, is the number of actively dividing cells observed within the tumor, known as the mitotic count.
Meningiomas often vary in symptom and treatment, and this largely depends on tumor location. Below is a list of central nervous system (CNS) locations where meningiomas can be found.
Tumor location determines both symptoms and treatment. A person may have subtle symptoms for a long period before the meningioma is diagnosed. Symptoms may include headaches, blurred vision, seizures, numbness, weakness in the arms or legs, or speech difficulty. Diagnosis is made by a MRI (magnetic resonance imaging) scan and/or contrast enhanced CT (computerized tomography).
Predisposing factors associated with meningiomas include exposure to radiation, prolonged use of certain hormones, and some genetic disorders (e.g. neurofibromatosis). Benign (noncancerous) meningiomas are also more common in women than in men, and may show increased growth during pregnancy.
Life-time exposure to radiation has been found to be associated with a higher incidence of meningiomas. For example, survivors of Hiroshima had an increased incidence of these tumors. For therapeutic uses of radiation, new methods use focused beams to limit unnecessary exposure to areas outside the target, and so are expected to be safer. Patients who have undergone broad radiation treatments in the past should watch for symptoms and monitor themselves for meningiomas. Meningiomas caused by known radiation exposure are generally more aggressive than other meningiomas.
People with a genetic disorder known as neurofibromatosis type 2 (NF2) are more likely to develop meningiomas. Of people with malignant meningiomas, a higher percent have mutations in NF2.
Patients with NF2 are more likely to develop meningiomas because they have inherited a gene that has the potential to cause normal cells to become cancerous.
Treatment plans vary based on tumor size, location, growth rate, association with neurologic symptoms, as well as the patient’s age and overall health. Meningioma treatment includes three options:
To schedule an appointment with a physician in the Brain Tumor Center, please contact our Patient Coordinator at: (617) 732-6600. We see new patients with a brain tumor diagnosis as soon as the next business day.
If you are a physician seeking to refer a patient to the Brain Tumor Center, please call (617) 732-6600 or you can access our physicians’ office phone numbers. To contact one of our physicians with a question, patient referral or second opinion, you may also email: BWHNeurosurgery@partners.org.
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