The tumor grows from the meninges, the layers of tissue covering the brain and spinal cord. As it grows, meningioma compresses other brain tissue which can affect cranial nerves. Sometimes the growth extends into facial bones, producing visible changes. It is usually benign (grade I) or low-grade. Still, the meningioma tumor can cause disability and be life-threatening. It also can be grade II or III.
* Cannot predict its rate of growth or how long it was growing prior to diagnosis
* Can arise after previous treatment from ionizing radiation or excessive X-ray exposure
* Grows slowly, which sometimes allows the brain to become accustomed to its presence
* Occurs at any age, but common among men and women, 40s to 50s
* Twice as common in women
* Can invade skull or metastasize to skin or lungs, although rare
Meningiomas are the most common primary brain tumors in adults. The annual U.S. incidence rate is: two per 100,000.