A noncancerous brain tumor is an unexpected cluster of abnormal cells in your brain. Most grow slowly. They can't spread to other parts of your body the way cancerous tumors do. But they can grow large enough to cause symptoms.
Your doctor may call it a benign tumor.
There are many kinds of noncancerous tumors. Each affects a different type of brain cell.
Even though they aren’t cancerous, it's important that you continue to follow up with your doctor. In rare cases, these tumors can become cancerous.
This is the most common kind of brain tumor. About one-third of them are this type.
Meningiomas start in the meninges, the protective cover around your brain and spinal cord.
Women are twice as likely as men to get meningiomas. You may be more likely to get this tumor if you:
- Were exposed to high doses of radiation
- Have the genetic condition neurofibromatosis type 1 (NF1) or type 2 (NF2)
Most meningiomas don't cause symptoms until they get bigger. Then they can cause:
These get their name from the cells where they start. Schwann cells surround nerve cells in the brain.
The most common type of schwannoma is vestibular schwannoma, which your doctor may call acoustic neuroma. It affects the vestibular nerve, which travels from your inner ear to your brain and helps you keep your balance.
People with NF2 are more likely to get schwannomas. Women are twice as likely as men to get them.
Symptoms of schwannomas include:
These tumors start in your pituitary gland, which sits at the base of your brain and makes hormones. The pituitary also directs other glands in your body to make their hormones.
Pituitary adenomas are common. Up to 1 in 5 adults have tiny tumors in their pituitary gland. Most of these tumors never grow or cause problems.
Women get these more often than men. Anyone can get these tumors, but people with the inherited disease multiple endocrine neoplasia type 1 (MEN1) are more likely to get them.
Some pituitary adenomas make hormones. These are called functional tumors.
Which symptoms you have depend on whether the tumor makes hormones and which ones it makes:
If it creates:
Adrenocorticotropic hormone (ACTH), you'll probably have symptoms of something called Cushing's disease. These can include weight gain, easy bruising, and weakness.
Other symptoms of these tumors include:
These tumors sometimes affect people with the genetic disease Von Hippel-Lindau syndrome.
- Numbness or weakness in the arms or legs
- Nausea and vomiting
- Trouble with balance and walking
- Loss of control over the bladder or bowels
This type starts from cells at the base of the brain near the pituitary gland. Craniopharyngiomas are made up of solid parts and fluid-filled pockets called cysts. They’re most common in children between 5 and 14 and in adults older than 45.
When a craniopharyngioma grows, it can cause symptoms like:
Gliomas grow in glial cells, which surround and support nerve cells in your brain and spinal cord.
These tumors affect both children and adults. But they're more common in adults. Men are slightly more likely to get a glioma than women.
People with inherited diseases like NF1 or tuberous sclerosis are more likely to get them.
Gliomas come in different grades based on how much (or how little) they look like normal cells and how rapidly they grow:
- Grade 1: These cells look almost normal. They grow very slowly.
- Grade 2: A bit of abnormality sets in. They can return after treatment as a higher grade.
- Grade 3: The cells reproduce quickly and are more aggressive than the first two grades.
- Grade 4: These cells look nothing like normal cells. They're very aggressive and grow very quickly.
How Doctors Diagnose These Tumors
Your doctor will ask whether you've had brain tumor symptoms like seizures, headaches, or nausea. You may need one or more of these tests:
- CT, or computed tomography. A powerful X-ray makes detailed pictures of your brain.
- MRI, or magnetic resonance imaging. Powerful magnets and radio waves make pictures of your brain.
- Biopsy. This test removes a small amount of cells from the tumor. Your sample is checked under a microscope to see if it has cancer cells.
- Lumbar puncture (also known as a spinal tap). This may be done to check for abnormal cells in the spinal fluid.
- Blood and urine tests. You may have these to look for hormones and other substances that tumors release in your body. Your doctor could use these to check how well your organs are working, too.
How They're Treated
Small tumors may not need treatment. Your doctor will check you regularly with CT or MRI scans to see if the tumor grows.
Bigger tumors are removed with surgery. Your surgeon will try to take out as much of the tumor as possible.
Radiation is another treatment. It uses high-energy X-rays to shrink tumors. Doctors use radiation on tumors when they:
- Can't be fully removed with surgery
- Come back after surgery
A type of radiation treatment called stereotactic radiosurgery is an option for some brain tumors. It aims high doses of radiation directly at your tumor to avoid harming nearby tissues.
Your doctor will discuss all of your treatment options with you and help you decide on a plan that’s best for you.