What is a meningioma?

Meningiomas are tumors found next to the brain. They come from the meninges, which are layers of tissue that cover the brain and spinal cord, most often the arachnoid cells. They tend to grow slowly and inward. Often they will have grown quite large before they are diagnosed. While they are usually benign (not cancer), they can still grow large enough to be life-threatening. Tumors that are cancer are called malignant. Some patients may have more than one meningioma. Meningiomas account for about one-third of all primary brain tumors. There are three types of meningioma by grade:

  • Grade I, (benign meningioma), which grows slowly
  • Grade II (atypical meningioma), which grows more quickly
  • Grade III (anaplastic/malignant meningioma), which grows and spreads quickly

These types of tumors are also called by names that indicate where they are found and by the types of cells that show up under the microscope.

Where are meningiomas most commonly found?

Most of these tumors are found on the outer surface of the brain. Often, they are found at the top of the brain. Sometimes, they can develop at the base of the skull.

What are the causes of meningiomas?

Research has shown that 40%-80% of all meningiomas have an abnormality in chromosome 22, which is involved in the suppression of the growth of tumors. This may occur spontaneously or part of a family history of neurofibromatosis type 2 or breast cancer. Previous radiation to the head is another risk factor. There is a correlation between hormones and meningiomas.

What are the signs and symptoms of meningiomas?

The most common signs are headaches and weakness in a hand or foot. Some symptoms are related specifically to the area of the brain that has the meningioma.

Other symptoms include:

  • Confusion
  • Drowsiness
  • Problems seeing and/or hearing
  • Personality changes
  • Nausea and vomiting
  • Twitching and seizures
  • Facial numbness or pain

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