Meningioma are tumors that grow from the meninges — membranes that surround the brain and spinal cord. They are the most common benign brain and central nervous system tumor in adults.
Scientists do not know what causes meningiomas, but they agree that an abnormality in chromosome 22 (involved with tumor suppression) is associated with them.
Symptoms
Meningiomas are slow-growing tumors that usually aren’t cancerous (benign). They originate from cells in the arachnoid layer, one of three layers that cover and protect your brain and spinal cord.
The most common symptoms are a headache that lasts for weeks or months, weakness or loss of balance and vision, and changes in speech, personality, or mood. These symptoms may occur in different parts of your body, depending on where the tumor is located. These symptoms are caused by pressure from the tumor on areas of your brain or spinal cord.
These tumors usually appear as small, round or oval-shaped growths that are often indistinguishable from normal brain tissue. They are typically found incidentally on a scan ordered for another reason. Meningiomas grow slowly and are sometimes present for years before they are discovered. They can also cause few or no symptoms, especially if they are located in the middle part of the brain.
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You’ll probably have a neurological exam to check your balance, coordination, and brain function. You’ll have an MRI or CT scan to get pictures of your brain and the area around it. Your healthcare team will also need to take a sample of tissue from the tumor, which is called a biopsy, to confirm the diagnosis and determine whether it’s malignant or benign. This tissue is analyzed by a neuropathologist.
Your treatment may depend on the grade of your meningioma, its location and symptoms, and whether it’s attached to your brain tissue or surrounding veins. Surgical removal of the tumor is generally recommended for malignant or symptomatic meningiomas, and it’s an option for people with lower-grade meningiomas that haven’t yet caused symptoms.
If you have a lower-grade meningioma, your healthcare team may recommend active surveillance. This means having follow-up MRI scans and appointments at regular intervals to monitor your condition and look for any growth. If symptoms do develop, your healthcare team will discuss treatment options. There are medicines under study that might treat certain types of meningiomas, and you may be able to take part in a clinical trial for these.
Diagnosis
A meningioma is typically diagnosed based on magnetic resonance imaging (MRI) and computed tomography (CT). Both tests take X-rays that create cross-sectional images of the brain. A CT scan may also use an iodine-based dye to improve the clarity of the image. Meningiomas have a characteristic appearance on these tests and are usually easy to detect. If the MRI or CT scan suggests a meningioma, the healthcare professional will order further imaging and possibly a biopsy.
A biopsy is the surgical removal of a small sample of tumor tissue for examination under a microscope to determine the type and grade of the meningioma. It is often performed during surgical resection of the tumor or as a separate procedure prior to therapeutic intervention. A thin needle enters the tumor under MRI or CT guidance to collect the sample, which is then sent to the laboratory for evaluation and diagnosis.
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If a meningioma is discovered and is causing symptoms, surgery is the usual treatment. However, in some cases, a surgeon might decide to monitor the tumor instead of removing it. This is more common for older patients or those who have other health conditions that might make surgery more risky. The decision to monitor is also made if the meningioma is expected to grow slowly and is not likely to affect a patient’s quality of life. A patient undergoing monitoring will have periodic MRIs to evaluate the growth of the tumor.
If a tumor is located in a space that prevents an open biopsy, another option is radiotherapy, which uses radiation to shrink the tumor and reduce the likelihood of it growing back. A neurosurgeon may also use this method if the location of the meningioma makes it difficult to reach with a surgical procedure. For example, meningiomas that occur behind the eyes can be challenging to remove surgically because they are in a tight spot where the surgeon must avoid the visual nerves and a key blood vessel. A neurosurgeon might be able to access the area with a technique called a craniotomy, which involves making a temporary window in the skull to allow for the tumor to be removed and then replacing the bone.
Treatment
Meningiomas are typically slow-growing tumors that originate from the meninges, the protective covering of the brain and spinal cord. In many cases, they may exist for years without producing symptoms. However, if they grow too large, they can cause problems by pressing on critical brain or spinal cord structures. Symptoms can include headache, weakness, loss of vision or hearing and changes in personality or behavior. These tumors occur more frequently in people with a hereditary condition called neurofibromatosis type 2 (NF-2).
If a meningioma is causing symptoms or it grows rapidly, surgical removal will likely be recommended by your doctor. The location of the tumor, its expected growth rate and your age will help physicians determine whether surgery is needed. A biopsy, or small sample of the tumor, may also be required to determine its grade and whether it is cancerous.
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Surgery for meningiomas can be performed through a traditional surgical incision or with advanced, minimally invasive techniques that minimize scarring. Depending on where the meningioma is located, doctors may be able to reach it through the nose or by removing just a piece of skull that covers the area. In cases where the meningioma is close to vital structures, surgeons will often perform a craniotomy. This involves creating a temporary window in the skull and removing the tumor through that opening, which is then repaired.
MRI-guided radiation therapy (IGRT) is another treatment option for some meningiomas, particularly those that are symptomatic or growing quickly. This technique uses focused, shaped radiation fields to destroy the tumor while sparing nearby tissue. Its effectiveness is enhanced by the use of a contrast agent that binds to water molecules in the brain, which helps the surgeon visualize and target the tumor cells.
For those who prefer not to undergo surgery, observation of a meningioma with periodic physical examinations and MRI scans is an option. This is especially useful for those who are older or have other health conditions that make surgery a riskier option. In these cases, your physician may recommend a monitoring plan that involves meeting with your treatment team on a regular basis to discuss any new symptoms and monitor the tumor for signs of growth or change.
Prevention
Getting a brain tumor diagnosis is unsettling, whether it’s benign or cancerous. The good news is that a large number of meningiomas can be cured or controlled with surgery and radiation. At MUSC Hollings, we use our unique combination of world-leading technology, teamwork and technical skill to deliver exceptional, individualized care to patients with meningioma. We have a comprehensive neurosurgery team that includes neuro-radiologists who interpret imaging, a group of highly trained neuro-pathologists who diagnose tumor type and a neuro-anesthesiologist who specializes in assisting surgical treatment of brain tumors.
Meningiomas are different than other types of brain tumors because they grow in the tough membranes that cover the brain and spinal cord, rather than in the brain tissue itself. As a result, meningiomas can be removed surgically, whereas other tumors are harder to get to and often require more complex procedures. In some cases, however, a meningioma can grow near critical brain structures, such as nerves and blood vessels. The risk of injuring these structures can prevent surgeons from removing a tumor completely.
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A surgical procedure called a craniotomy may be used to remove a meningioma that is causing symptoms or is growing rapidly. The procedure involves removing part of the skull to allow the surgeon to reach the area where the tumor is located. The surgeon then removes the meningioma or as much of it as possible. The type of craniotomy and approach used to access the affected area depends on where the tumor is located, as some areas of the skull are more difficult to open than others.
After a surgical removal, doctors can monitor a meningioma for signs of growth with regular brain scans. If a meningioma is small and slow-growing, it may not need to be treated at all. If the doctor determines that the meningioma needs to be treated, it will be given a grade, which reflects how aggressive and fast-growing it is. Meningiomas with a grade of 1 have the best prognosis.
Strickland spends half of his time at MUSC Hollings researching new therapies for meningiomas that aren’t responsive to current treatments. He is looking into strategies that could target the tumor immune microenvironment to help the body fight off these tumors. His research is also focused on developing a way to predict which meningiomas are likely to be malignant or anaplastic. This information could lead to more effective and safer treatments in the future.
