Overview

The brain and spinal column make up the central nervous system (CNS), where all vital functions of the body are controlled. When a tumor forms in the CNS, it can be especially problematic because a person’s thought processes and movements can be affected. This type of tumor can also be more difficult to treat because the tissues surrounding the tumor may be vital to functioning.

This guide focuses on meningioma, a type of tumor that occurs in the meninges, which are the thin membranes that surround and protect the brain and spinal cord. There are three meningeal layers called the dura mater, arachnoid, and pia mater. A meningioma is a slow-growing tumor that usually forms on the surface of the brain and may cause significant symptoms if it grows and presses on the brain or spinal cord. Approximately 85% of meningiomas are benign (noncancerous). The remaining 15% are atypical (a type of slow-growing tumor that has the potential to turn cancerous and spread to other parts of the body) or, in 1 - 2% of cases, malignant (cancerous).

Subtypes

Meningioma is classified into subtypes based on the location of the tumor.

Falx and parasagittal meningioma (accounts for 25% of meningioma cases). The falx is a membrane sitting in a groove that runs between the two sides of the brain. It contains a large blood vessel. Parasagittal meningioma occurs near the falx.

Convexity meningioma (20%). This type of meningioma occurs on the upper surface of the brain.

Sphenoid meningioma (20%). The sphenoidal ridge is located behind the eyes. Sphenoid meningioma occurs mostly in women.

Olfactory groove meningioma (10%). This type of meningioma occurs along the nerves that connect the brain to the nose.

Posterior fossa meningioma (10%). Posterior fossa meningioma develops at the back of the brain, on its underside.

Suprasellar meningioma (10%). Suprasellar meningioma occurs next to the sella turcica, a box at the base of the skull where the pituitary gland sits.

Spinal meningioma (less than 10%). Most common in women between the ages of 40 and 70, a spinal meningioma will usually occur in the spine at chest level and may push against the spinal cord. Spinal meningioma may cause such symptoms, as pain radiating around the chest wall, bladder trouble, and/or weakness or numbness in the legs.

Intraorbital meningioma (less than 10%). This type of meningioma develops in or around the eye sockets.

Intraventricular meningioma (2%). Intraventricular meningioma occurs in the chambers that carry fluid throughout the brain.

Statistics

Meningioma accounts for approximately 15% of primary brain tumors (tumors that start in the brain) in the United States and occurs in approximately six of every 100,000 people. Meningioma is rare in children.

The two-year relative survival rate (the percentage of people who survive at least two years after the meningioma is detected, excluding those who die from other diseases) for meningioma that can be surgically removed is 82%. The five-year and 10-year relative survival rates for meningioma that can be surgically removed are 72% and 60%, respectively.

Cancer survival statistics should be interpreted with caution. These estimates are based on data from thousands of cases of this type of tumor in the United States each year, but the actual risk for a particular individual may differ. It is not possible to tell a person how long he or she will live with meningioma. Because survival statistics are often measured in multi-year intervals, they may not represent advances made in the treatment or diagnosis of this cancer.

Sources: National Cancer Institute, Central Brain Tumor Registry of the United States, and Castillo, German C., MD, FCIS “Meningioma, Brain” eMedicine, 27 April 2007 http://www.emedicine.com/RADIO/topic439.htm

Find out more about basic cancer terms used in this section.