Meningiomas are the most common benign intracranial tumor. Meningiomas form on membranes that cover the brain and spinal cord just inside the skull called the meninges. Specifically on the arachnoid. Although meningiomas are benign, these tumors can grow if not discovered or if untreated they can be severely disabling and life-threatening. Most patients develop a single meningioma, however some patients may develop several tumors growing simultaneously in other parts of the brain or spinal cord.
Although the causes of meningiomas are not well known or understood, there are known risk factors such as exposure to radiation and Neurofibromatosis Type 2 which is a genetic disorder. Previous head injury may also be a factor. Meningiomas may also be associated with the hormone progesterone and middle-aged women are three times as likely as men to develop the condition. Most meningiomas occur between the ages of 40 and 70.
Because meningiomas are slow growing tumors, often they do not cause noticeable symptoms until they are quite large. Some people may not show any symptoms throughout their life and may be detected when they have a brain scan for unrelated reasons. However when people do have symptoms, they may depend on the size and location of the tumor. Symptoms may include:
- Change in personality or behavior
- Hearing loss or tinnitus (ringing in the ears)
- Muscle weakness
- Nausea or vomiting
- Visual disorders