A meningioma is a type of meningeal tumor.  Meningeal tumors arise from the thin layers of tissue that cover the brain and spinal cord, rather from the actual brain tissue.  Most meningiomas are benign, slow-growing tumors.  They often grow inward exerting pressure on the brain and spinal cord.  In other cases, they grow outward and cause the skull to thicken.  Meningiomas may contain cysts, mineral deposits, or clusters of blood vessels. The most common sites include the coverings located near the top of the brain, the outer curve of the brain, and the skull base. 

Meningiomas account for about 15%-20% of all primary brain tumors.  They are most likely to be diagnosed in adults older than 60 years.  Incidence seems to increase with age, and they occur about twice as frequently in women as in men.  They rarely occur in children.

Tumor Classification

Meningiomas are often classified by tumor grade:

Benign:  Contain cells well-differentiated cell types (resembling normal cells) that tend to grow slowly.  About 80% of meningiomas are benign.

Atypical:  Contain proliferating cells that are faster growing and more likely to grow back after treatment.  Because these cells may grow back after a seemingly complete resection, atypical tumors should be followed closely.  Represent about 10-20% of meningiomas.

Malignant (or anaplastic):  Contain poorly differentiated cell forms that often grow back rapidly.  These are rare, but can be very aggressive and difficult to treat.  Represent 1-2% of meningiomas.

Meningiomas may also be classified by type of cell.  For example:

  • Syncytial meningioma refers to meningiomas that consist of cells that are unusually plump in type.
  • Fibroblastic meningioma refers to meningiomas that consist of cells that are long and thin in shape.
  • Transitional meningiomas refers to meningiomas that consist of cells that are of both cell types.

Meningiomas may also be classified by location of tumor.  For example:

  • Parasagittal meningioma refers to a meningioma that is located near the sagittal sinus, a major blood vessel near the top of cerebral hemisphere.

Symptoms
Meningiomas are usually slow growing, but may grow to a large size before symptoms appear.  Symptoms vary depending on the tumor’s location, and often begin with headache or arm/leg weakness due to pressure on the brain from the growing tumor.  Seizures, personality change, and visual problems are other possible symptoms.  Pain, weakness, and/or loss of feeling in the arms or legs are common symptoms of spinal cord meningioma.

Diagnosis
A neurological exam, MRI, and CT scan are among the diagnostic tests used to help determine tumor location, size, and probable type.  The exact diagnosis requires a surgical biopsy or excision to remove a sample of the tumor tissue for examination.

Treatment
Surgery is the primary treatment for meningiomas.  The goals of surgery are to obtain tumor tissue for exact diagnosis and to remove as much of the tumor as safely possible. Some meningiomas, although benign, can be difficult to treat because they are located in areas that are difficult to reach or functionally sensitive.  Radiation is often used for inoperable tumors or tumors that are not completely removed by surgery, as well as for malignant tumors and recurrent tumors.  Conventional external beam radiation (“standard radiation”) may be used alone or in conjunction with “local radiation” (such as stereotactic radiosurgery and intensity modulated radiation therapy).

Medications may also be prescribed to treat symptoms of the tumor.  Anti-epilepsy drugs are used to prevent or control seizures; anti-emetics are used to manage nausea/vomiting; and steroids are used for edema (swelling) around the tumor.  A meningioma may recur in cases where all of the tumor cells are not removed with treatment.  Your physician can discuss the likelihood of your particular tumor reoccurring.

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