What is Meningioma?

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.

How is Meningioma classified?

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.

• Convexity meningioma: These grow on the surface of the brain, often toward the front and top of the brain. They may not produce symptoms until they reach a large size. Symptoms of a convexity meningioma are diverse, and include headache, seizures, weakness, numbness, vision loss, or other focal neurological deficits.
• Falcine and Parasagittal meningiomas: The falx is a double-thickness membrane that divides the two sides of the brain (front to back). Falcine meningiomas arise from one or both sides of this membrane and may spread along the falx to extend far from the original tumor site. A major a blood vessel runs along the top of the falx (superior sagittal sinus) and is responsible for draining blood from a large sector of the brain. Large parasagittal meningiomas may result in leg weakness. Falcine and parasagittal meningiomas are more likely to be higher-grade than meningiomas in other locations of the brain.
• Olfactory groove meningiomas: Olfactory groove meningiomas grow at the base of the skull in the front of the head, behind the top of the nose. They can grow to a large size prior to being diagnosed because of loss of sense of smell, altered personality, or changes in mental status.
• Sphenoid wing meningiomas: Sphenoid meningiomas grow at the base of the skull on either side. These tumors can cause bulging of the eye, visual problems, altered sensation in the face, or seizures. Sphenoid wing meningiomas sometimes involve the critical blood vessels supplying vessels the brain (e.g. carotid artery branches).
• Petrous and Petroclival meningiomas: Meningiomas of the petrous bone grow at the base of the skull and may involve a number of critical cranial nerves, including that supplying sensation to the face, the hearing nerve, the nerves controlling facial movement and eye movements. These are some of the most challenging meningiomas to treat and should be evaluated by a skull base specialist.
• Posterior fossa meningiomas: Posterior fossa tumors arise in the back of the head. These tumors are associated with many different symptoms, depending on their point of origin. They include tentorial meningiomas, posterior petrosal and petroclival meningiomas, jugular foramen meningiomas, and foramen magnum meningiomas. Because of the tight space in the back of the brain, growth of these tumors can cause elevated pressure in the brain, leading to headaches, unsteadiness, or dizziness. They can also lead to changes in voice and swallowing, decreased hearing, and changes in facial strength or double vision.
• Intraventricular meningiomas: Intraventricular meningiomas arise from chambers of cerebrospinal fluid, which circulates throughout the brain and spine. They can block the flow of cerebrospinal fluid and causing an increase in pressure, leading to headaches and dizziness.
• Intra-orbital meningiomas: Intra-orbital meningiomas grow around the eye sockets of your skull and can cause pressure in the eyes, resulting in a bulging appearance. They can also cause an increasing loss of vision.
• Spinal meningiomas: Spinal meningiomas account for less than 10 percent of meningiomas. They are intradural (within or enclosed within the dura mater), extramedullary (outside or unrelated to any medulla) tumors occurring predominantly in the thoracic spine. They can cause back pain, numbness, or weakness in the limbs from compression of the spinal cord or the exiting of the spinal cord.

What are the symptoms of Meningioma, and how is Meningioma diagnosed?

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).

What are the risk factors for Meningioma?

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.

Radiation Exposure

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.

Genetic Predisposition

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.

How is a Meningioma treated?

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:

• Observation for small tumors not causing symptoms. Patients will have CT or MRI scans to monitor for tumor growth.
• Surgery to remove the tumor. The goal is to remove the entire tumor and the membranes from which it originates. Complexity of the surgery depends on the tumor’s location and involved nerves and blood vessels.
• Radiation may be used in combination with surgery to treat patients with aggressive meningiomas.

Learn more about Meningioma Treatment at Brigham and Women’s.

Contact the Brain Tumor Center

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.