Meningiomas are tumors that develop from the membrane (meninges) that covers the brain and spinal cord. They are the most common primary brain tumor in adults. Most meningioma tumors (85-90%) are categorized as benign, with the remaining 10-15% being atypical meningioma or malignant meningioma (cancerous).
The word “benign” can be misleading for meningiomas. Depending on location and growth rate, a benign meningioma brain tumor 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% 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.
Meningioma types are commonly divided into three grades, with 15 histopathologic subtypes based on the individual tumor appearance. Traditionally, one of the most important features 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.
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.
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 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 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 before being diagnosed because of loss of sense of smell, altered personality or changes in mental status.
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 to the brain (e.g., carotid artery branches).
Meningiomas of the petrous bone grow at the base of the skull and may involve several critical cranial nerves, including those 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 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 meningioma 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 arise from chambers of cerebrospinal fluid, which circulates throughout the brain and spine. They can block the flow of cerebrospinal fluid and cause an increase in pressure, leading to headaches and dizziness.
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 account for less than 10% 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.
Meningioma grades are based on the tumor location, meningioma type, spread and potential for the tumor to remain after surgery. Meningiomas may require molecular testing to determine its grade.
The World Health Organization (WHO) also classifies brain tumors, highlighting 15 variations of meningiomas based on cell type. The meningioma WHO grading system includes atypical meningiomas in WHO Grade II and anaplastic malignant tumors in WHO Grade III.
Tumor location determines both meningioma symptoms and potential meningioma treatment.
The symptoms of meningioma may occur gradually, starting relatively minor. These subtle symptoms may persist for a long period of time before a meningioma diagnosis. Based on the location of the meningioma, symptoms may include:
A small meningioma likely won't cause symptoms and may only be noticed during routine imaging exams. As a meningioma grows, signs of meningioma will likely increase.
A meningioma diagnosis is made after an imaging exam. Many tumors are slow growing, so without a sudden onslaught of symptoms, meningioma isn't often the first consideration when symptoms do start to appear. To identify a meningioma, imaging tests may include:
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 men and may show increased growth during pregnancy.
Life-time exposure to radiation has been 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 that use focused beams to limit unnecessary exposure to areas outside the target 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 percentage 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.
Meningioma 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:
Meningioma causes aren't fully understood. Risk factors include extensive radiation exposure, the NF2 genetic disorder and gender. Female hormones may explain the increased occurrence of meningioma in women.
A meningioma prognosis is dependent on the size, location and growth rate of the tumor. A small, benign tumor may not pose a great risk to an individual, and they could easily live for many years without symptoms. A malignant meningioma prognosis often requires surgical intervention to improve the quality and life expectancy of the patient.
An untreated meningioma that continues to grow can cause a worsening of symptoms and eventually serious medical complications and life-threatening situations for those living with meningioma.
Our team of maternal-fetal medicine specialists (high risk obstetricians), radiologists, surgeons, nurses, and other medical specialists provide supportive and compassionate care before, during, and after pregnancy for women who have or are at risk of having pregnancy complications. This care includes counseling, evaluation, and medical and surgical care.
A meningioma is a type of tumor growing near the brain. While roughly 90% of these tumors are benign, some do become cancerous
Individuals with the genetic disorder neurofibromatosis type 2 (NF2) have a greater chance of developing meningiomas. For those with NF2, meningiomas can be based on an inherited gene.
Depending on the size and location of a meningioma, it is entirely possible to live a normal life with a meningioma. Regular monitoring of the tumor and a close watch of symptoms is needed to ensure there isn't growth.
The neurosurgeons at Brigham and Women's Hospital offer state-of-the-art treatment options for patients with primary and metastatic brain tumors. Our neurosurgeons collaborate with other specialists to provide individualized care for every meningioma patient, from diagnosis through treatment and follow-up. Our neurosurgeons are known for their innovation in neuroimaging and surgical techniques for treating meningioma. As a result, we can safely remove tumors that other centers may consider inoperable.
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