Meningioma is the most common type of primary brain tumor, accounting for approximately 30% of all brain tumors. Meningiomas originate in the meninges, which are the outer three layers of tissue between the skull and the brain that cover and protect the brain just under the skull. Meningiomas grow out of the middle layer of the meninges, called the arachnoid. When they grow, they press against the brain or spinal cord.

About 85% of meningiomas are benign (non-cancerous, slow growing) tumors. Meningiomas can often be removed entirely with surgery. Some meningiomas may not need immediate treatment and can often remain undetected for many years.

Causes and risk factors for Meningioma
There is no obvious cause of a meningioma. However, this type of brain tumor is about three times more common in women than in men. Other risk factors that increase the chance of getting a meningioma are:

Signs and symptoms of meningioma:

A meningioma can cause symptoms by pressing on the brain or spinal cord. However, many meningiomas are found incidentally on MRIs leading from a patient visit that often has little to do with the meningioma itself. Symptoms, if present, appear slowly and may be slight at first. Symptoms are location dependent, meaning that the symptom corresponds to the part of the brain that the tumor is pushing on.

The most common symptoms are:

Other symptoms include: