Meningiomas
Meningiomas are usually benign tumors that come from the meninges or dura, which is the tough outer covering of the brain just under the skull. This type of tumor accounts for about 25 percent of brain tumors. They are slow growing and may exist for years before being detected. Meningiomas are most common in patients in their 40s and 50s. They are commonly found in the cerebral hemispheres just under the skull. They usually are separate from the brain and can sometimes be removed entirely during surgery. They can, however, recur after surgery and certain types can be malignant.