Meningiomas are a common type of brain tumor that grows in the meninges, the membranes that cover the brain and spinal cord. They account for 40% of all reported brain tumors. These tumors typically grow slowly and can go undetected for years. While they usually do not invade brain tissue, their growth can put pressure on the brain and spinal cord, leading to symptoms. In most cases, meningiomas are treatable and can be surgically removed. There are three grades of meningiomas, ranging from non-cancerous to cancerous and aggressive, which determine their severity and necessary treatment.