Meningiomas are usually slow growing and, therefore, may grow to a large size before causing symptoms. The symptoms of a meningioma are caused by the pressure the growing tumor exerts on surrounding brain or nerves. Depending on the location of the mass, meningiomas may cause headaches, seizures, weakness or numbness in the limbs or face, visual problems, and gradual changes in mood or personality. The symptoms tend to increase in severity as the tumor grows in size.
Olfactory groove meningiomas often lead to the loss of the sense of smell. If they grow large enough, they can also compress the optic nerves to the eyes and surrounding brain, causing visual symptoms, headaches, seizures and personality changes. Sphenoid wing meningiomas can cause visual problems, including loss of peripheral vision and even unilateral mon-occular blindness. In addition, they can cause facial numbness, double vision, headaches and seizures.
These tumors are diagnosed with a neurological examination followed by imaging studies of the brain, usually a computed tomography (CT) or magnetic resonance imaging (MRI) scan. The scan is usually performed with a contrast dye that makes the border and details of the tumor more visible in relation to the surrounding normal brain. The scan also provides detail information regarding the exact size, location and other structures involved by the tumor. An angiogram, which allows physicians to visualize the blood vessels in the area, may also be used for emobolization of a very vascular tumor and closing off its blood supply. Only examination of a patient’s tumor tissue under a microscope can confirm an exact diagnosis. This tissue is usually obtained with tumor resection.
If a particular meningioma is small and does not cause any symptoms, it may be observed over time rather than treated immediately. In this situation surveillance MRI scans will be recommended to monitor the stability of the tumor over time. In cases in which treatment is necessary, surgery is usually the primary form of treatment for a meningioma. Because most meningiomas are benign, and rarely invade the surrounding brain tissue, complete resection often results in a cure.
With contemporary microsurgical and skull base techniques, many of these tumors now can be removed. Prior to surgery, some patients can benefit from embolization of the blood supply to a meningioma which can make complete removal easier for the surgeon. Usually surgery is performed with a frameless stereotactic navigation system in which a high-resolution MRI is used to construct a three-dimensional brain model that allows for minimally invasive surgery. While every effort is aimed at total removal, certain tumors present a formidable technical challenge because they adhere to vital neural and vascular structures at the base of the brain. After surgery, the tumor tissue is microscopically examined to establish an accurate diagnosis, assess the risk of recurrence and dictate the next step in treatment.
Conventional external beam radiation therapy may be used as a follow-up treatment, especially for malignant or atypical tumors that have recurred. In addition, non-invasive, stereotactic radiosurgery (CyberKnife and Gamma Knife) may be used as either primary or adjunct treatment for small or residual tumors in difficult to reach locations or in patients that cannot undergo surgery. Stereotactic Radiosurgery uses numerous finely focused beams of radiation to accurately target the tumor and while minimizing the effects to any surrounding tissue. The target tumor is usually outlined on a 3-Dimensional model of the brain by the neurosurgeon and the radiation oncologist prior to the procedure.
After surgery, each patient is reviewed at our Multi-Disciplinary Tumor Board with an expert team of neuro-oncologists, medical oncologists, neuro-pathologists, neuro-radiologists and neurosurgeons. Together the tumor board recommends the best treatment options for each patient, incorporating ongoing national clinical trials and the latest treatment protocols.