Diagnosing Meningioma

Meningiomas are tumors that develop in the meninges, the three layers of connective tissue that cover the brain and spinal cord. The majority of meningiomas are benign, meaning they don’t contain cancer cells and grow slowly. But some tumors are atypical, meaning the cells act more aggressively and grow more quickly. Very rarely, meningiomas are malignant, meaning they contain cancer.

Most meningiomas grow on the surface of the brain and spinal cord. However, some meningiomas grow at the base of the skull, an area underneath the brain. This area, located behind the nose and eyes, contains many nerves, blood vessels, and other important structures.

Rarely, meningiomas occur in the ventricular chambers, the inner portions of the brain that contain cerebrospinal fluid. This fluid cushions and protects the brain and spinal cord. A small percentage of tumors grow in the layer of tissue that covers the spinal cord.

Depending on their location, these tumors can cause various symptoms. Symptoms are caused by pressure on critical nerves, areas of the brain, and the brainstem, which connects the brain to the spinal cord. Meningiomas of the brain or skull base can cause headache, weakness on one side of the body, seizures, vision changes, memory loss, or problems with balance and walking. Spinal meningiomas can cause weakness, numbness, and pain in the arms or legs.

The causes of meningioma are not completely understood. These tumors are more common in women than men and are most likely to occur in people ages 30 to 70. People with certain genetic conditions, such as neurofibromatosis type 2, are also at risk. Previous radiation therapy to the head for treatment of other tumors, especially during childhood, may also lead to the development of brain or skull base meningiomas.

To diagnose the condition, your NYU Langone doctor asks about your medical history and looks for symptoms associated with meningioma. A detailed neurological examination is then done to define if the tumor is producing any signs of neurological changes. Tests may include a detailed vision examination and hearing test.

Your doctor may order imaging tests to identify the tumor.

MRI Scans

An MRI scan uses magnets and radio waves to create detailed three-dimensional images that are sent to a computer. Our doctors use a contrast agent, which is injected into a vein before the procedure, to enhance images of the brain and skull base and the spine (for spinal meningiomas).

Meningiomas can be identified by their location and shape, as well as how the cells appear when enhanced by the contrast agent. The diagnosis can be made with a high likelihood of accuracy, but the ultimate proof is the examination of tissue under a microscope, after the tumor has been removed with surgery.

CT Scans

Meningiomas, whether benign or malignant, can invade the skull. If after an MRI, doctors suspect a tumor is affecting the bone, they may order a CT scan, which is often better at detecting changes in bone than other imaging tests are. Meningiomas can affect the bones of the skull by causing bone destruction or, more often, excessive bone growth, also called hyperostosis.

In a CT scan, a series of X-ray images is sent to a computer to create three-dimensional, cross-sectional pictures of the head. Before the test, you may receive a contrast agent through an injection into a vein to enhance the CT image. The CT scan exposes you to a very low level of radiation.

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