A meningioma is a tumor that grows from the meninges — the protective membranes that cover the brain and spinal cord. Most meningiomas are benign (not cancer) and slow growing; however, some can be malignant. Symptoms typically appear gradually and vary depending on the tumor location. Because of their slow growth, not all meningiomas need to be treated immediately. Treatment options focus on removing the tumor and relieving the compression on the brain.
What is a meningioma?
Three layers of membranes, called meninges, lying just under the skull, protect the brain and spinal cord. From the outermost layer inward they are: the dura, arachnoid, and pia. A meningioma grows from the arachnoid cells that form the middle layer, and are firmly attached to the dura. Some meningiomas contain cysts or calcified mineral deposits, and others contain hundreds of tiny blood vessels. Because meningiomas tend to grow inward, they commonly cause pressure on the brain or spinal cord. They can also grow outward causing the skull to thicken (hyperostosis).