A Meningioma is a tumor of the central nervous system that develops from cells of the meninges (the Dura matter, arachnoid, and pia matter) and spinal cord. In most cases 90% of Meningiomas are benign (non-cancerous) and do not tend to spread out to the rest of the body or nervous system. These tend to grow at a very slow rate and usually show no symptoms until the tumor gets relatively large. This is due to the gradual compression of the brain over time. Although benign tumors are not cancerous they can cause serious damage due to the location in the brain or spinal cord. In rare cases, about 2% of the Meningiomas can be malignant (cancerous) and are more aggressive. They grow at a faster rate and have a higher chance of reoccurring. 7% of all Meningiomas are known to be atypical which means that they are neither benign nor malignant but rather something in between. Only 1% of all Meningiomas are developed in the spinal cord. These tumors grow at a slow rate and usually between the neck and the abdomen. Symptoms usually occur when the tumor compresses on the spinal cord. Meningiomas get their name by the location where they arise. There are several types of Meningiomas. Convexity Meningiomas (20%) grow on the surface of the brain and show no symptoms until the tumor reaches a fairly large size. Falx and Parasagittal Meningiomas (25%) grow from the fold that runs between the left and right side of the brain. Olfactory Groove Meningiomas (10%) grow along the olfactory nerves that run between the brain and the nose. Sphenoid Meningiomas (20%) grow along the sphenoid ridge, which lies behind the eyes. Posterior Fossa Meningiomas (10%) grow along the underside of the brain near the brainstem and the cerebellum. Intraventricular Meningiomas (2%) grow inside the fluid-filled ventricles deep inside the brain. Spinal Meningiomas (less than 10%) grow predominantly in the thoracic spine. The causes of...
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