Meningioma

A meningioma is a type of tumor that grows in the layers of tissue that cover the brain and spinal cord. Technically, a meningioma is not a brain tumor because it does not arise from brain tissue. But it's often referred to as a brain tumor.

These tumors are usually noncancerous (benign). Although rare, higher grade meningiomas can become cancerous (malignant). As these tumors grow, they can compress the brain and spinal cord, leading to serious neurological problems.

Meningiomas are the most common type of brain tumors in adults. They are more common in women and tend to be found in people around 60 years old.

Most cancer centers that treat brain tumors use a grading system developed by the World Health Organization. A tumor's grade is determined by looking at cells from the tumor under a microscope. Tumor grading is important because it is one factor that helps doctors decide how to treat a tumor.

Meningiomas are broken down into low, mid and high grades based on their characteristics. The lower the grade, the less likely they are to spread, and they are easier to treat. Higher grade meningiomas tend to grow more quickly and are harder to treat. Over time, some low-grade tumors become high-grade tumors.

• Grade I—These meningiomas are low grade tumors and are considered to be benign and slow growing. They may be treated with surgery and they rarely come back. You can often expect long-term survival.
• Grade II—Classified as mid-grade tumors, these meningiomas grow a bit quicker and higher chance of coming back after being removed. 
• Grade III—A more rare meningioma, these tumors are malignant (cancerous). They are fast-growing, spread more rapidly and are harder to treat.

The underlying cause of meningiomas is not clear. Hormonal fluctuations may encourage the growth of these tumors. But more research is needed to confirm this.

Researchers have found a chromosome defect in a significant percentage of meningiomas. This suggests that the tumors may be caused by genetic-related factors. The specific chromosome involved functions to suppress tumor growth.

Women are much more likely to get meningiomas than men. This has led experts to suspect that certain hormones might play a role in the development of these tumors. Other people at higher risk include those who have had radiation treatment to the head and people with neurofibromatosis. This is an inherited nervous system disorder.

These tumors usually grow slowly. You may not have any symptoms until the tumor has become large. The tumor can cause different symptoms, depending on where it's growing. These are possible symptoms:

• Vision or hearing loss.
• Seizures.
• Trouble thinking clearly.
• Trouble walking.
• Loss of smell.
• Weakness in an arm or leg.
• Headache.
• Nausea.

Meningiomas often come to light because of symptoms a person is having. To diagnose meningiomas, these tests may be done:

• Neurological exam. Your healthcare provider will ask about your symptoms and may do a neurological exam to look for changes in motor and sensory function, vision, coordination, balance, mental status, and in mood or behavior.
• Imaging. Your healthcare provider may diagnose a meningioma using an MRI or CT scan to get a picture of the brain and nearby structures.
• Biopsy. In addition, your provider may want to remove a sample of the tumor to examine it under a microscope before making the diagnosis.

If your meningioma is causing symptoms or is growing, your healthcare provider will likely want to remove it with surgery. In some cases, though, trying to remove the tumor may be too risky. For example, the tumor may be too close to a vital brain structure or blood vessel.

If you do have surgery, the surgeon will try to take out as much of the tumor as possible. The surgeon may use MRI images of your brain to help guide the surgery. The surgeon may also use a special microscope during the surgery to get a better view of the tumor and the surrounding parts of your brain.

If the surgeon can't remove the tumor — or can only remove part of it — you may need radiation therapy. Depending on the areas of the brain or spinal cord that are involved, radiation therapy may help shrink any remaining tumor and can also help prevent it from spreading to the tissues around it. Even if the tumor is completely removed during surgery, some healthcare providers may still recommend radiation therapy to help prevent another meningioma from developing in the future. Meningiomas have a tendency to grow back after surgery.

Your healthcare provider may also recommend medicine to treat the tumor. Experts are studying several medicines to see if they work against meningiomas. You may need to take part in a study to use these medicines.

You may also be able to use other medicines to treat symptoms caused by the meningioma, such as seizures, excessive vomiting, weakness, and vision disturbances.

In many people, meningiomas don’t cause any symptoms and grow quite slowly. For this reason, experts might recommend watchful waiting. This means you will report any new symptoms to your healthcare provider. He or she will also order scans on a regular basis to track even minor changes in the tumor. This may be a reasonable option for managing small tumors that aren't causing symptoms, especially in older adults who may not be able to have surgery or radiation therapy because of other medical conditions.