A meningioma is a type of tumor that develops from the meninges, the membrane that surrounds the brain and spinal cord. There are three layers of meninges, called the dura mater, arachnoid and pia mater. Most meningiomas (90%) are categorized as benign tumors, with the remaining 10% being atypical or malignant. However, the word “benign” can be misleading in this case, as when benign tumors grow and constrict and affect the brain, they can cause disability and even be life threatening.
In many cases, benign meningiomas grow slowly. This means that depending upon where it is located, a meningioma may reach a relatively large size before it causes symptoms. Other meningiomas grow more rapidly, or have sudden growth spurts. There is no way to predict the rate of growth for a meningioma, or to know for certain how long a specific tumor was growing before diagnosis.
Most people with a meningioma will only have a tumor at only one site, but it is also possible to have several tumors growing simultaneously in different parts of the brain and spinal cord. When multiple meningiomas occur, more than one type of treatment may have to be used.
Meningiomas vary in their symptoms and appropriate treatment options depending on where they are located.
A primary brain tumor originates in the central nervous system, while metastatic brain tumors spread to the brain from other parts of the body. Meningiomas account for about 27% of primary brain tumors, making them the most common of that type.