What is a brain tumor? A Mayo Clinic expert explains

Learn more about brain tumors from neuro-oncologist Alyx Porter, M.D.

I'm Dr. Alyx Porter, a neuro-oncologist at Mayo Clinic. In this video, we'll cover the basics of brain tumors: What is a brain tumor? Who gets it? The symptoms, diagnosis and treatment. Whether you're looking for answers for yourself or someone you love, we are here to give you the best information available. First, let's talk about what a brain tumor is. DNA tells our cells what to do. Sometimes this DNA mutates and tells cells to duplicate abnormally, dividing rapidly and living longer than healthy cells are supposed to. These cells collect into a mass, in this case, in various parts of the brain. And since the brain is the control center for the rest of our bodies, this can affect all kinds of other functions. There are many kinds of brain tumors. Some are benign or non-cancerous. In other words, it's an overgrowth of cells that produces a mass. But the cells themselves are normal. Some are malignant or cancerous. This means the mass is composed of abnormal cells that will continue to spread and invade to other tissues. Tumors that originate in the brain or surrounding tissues are known as primary brain tumors. More often, the tumor is known as a secondary or metastatic brain tumor - the result of cancer from elsewhere in the body that is spread to the brain.

We often just don't know why primary brain tumors form. Statistically, in adults, age increases your risk of having a primary brain tumor. And they are more common in women than men. Exposure to some kinds of radiation, including prior cancer treatment, can increase your risk. And there are some rare inherited syndromes that seem related to brain tumor development. But they're not really predictable nor preventable. When it comes to secondary tumors, we know that they spread from cancer in other parts of the body. And the cause of that original cancer, depending on where it started, could have resulted from genetic or external factors. It's not common, but sometimes a brain tumor can be the first indication of cancer elsewhere.

Usually, the first sign of a brain tumor is a headache, generally in conjunction with other symptoms. These may include: seizures, difficulty thinking or speaking, changes in personality, anxiety, depression, disorientation, fatigue, abnormal eye movements, numbness or tingling on one side of the body, weakness on one side of the body, loss of balance, vision changes, memory loss, nausea, generalized pain, trouble swallowing, trouble walking, drooping on one side of the face, loss of appetite, weight loss, and slurred speech. That doesn't mean if you have a headache or even a headache with these other symptoms that you have a brain tumor. But if you notice a headache that awakens you from sleep, that seems to be at its worst in the early morning hours, along with dimming of your vision, this could be a sign of increased intracranial pressure. And you should make an appointment with your doctor.

There are a variety of tests and procedures your doctor may recommend for determining the cause of your symptoms. First, you will most likely be given a neurological examination. This will evaluate your vision, hearing, balance, coordination, strength, sensation, and reflexes. They may recommend imaging tests, such as an MRI or a CAT scan or a PET scan, to get a clearer picture of the brain. If a tumor is detected, a surgical procedure may be done to determine the nature of the mass or its type.

Although a brain tumor diagnosis can be overwhelming and scary, know that there are experts in the field who will work with you to figure out the best strategic course for your individual situation. So the most important thing you can do is to find a specialized treatment center that feels like a good fit and get a second opinion or even a third. It's important to feel confident in your care team and their support as you fight this battle together. Treatment depends on a lot of factors: the type, size, and location of the tumor, as well as your overall health and personal preferences. You and your care team will collaborate to map a course for the best quality of life ahead. If the tumor is in a place where removal is a viable option, surgery may be recommended to take out as much of the mass as possible. Even if the entire thing can't be removed safely, eliminating a portion can help alleviate symptoms. Another possibility is radiation. There are a few different forms of delivery, but all use high-energy radiation to target and destroy cancerous cells. There's chemotherapy, in which powerful drugs that combat cancer cells are taken either orally or through an IV. For certain kinds of cancer, targeted drug therapy may also be an option. These blocks specific abnormalities within the cancer cells, causing them to die. You may qualify for clinical trials, as well, for experimental measures that are showing promise. Your doctors can help guide you and recommend to you if this seems like the best plan of action. All of these treatments have side effects - some quite severe. These can include issues with memory and thinking, motor skills, vision, and speech, as well as other physical or emotional symptoms. Your doctors can recommend a course of supportive and palliative care to help you get through the treatment itself. In addition, physical therapy, speech therapy, occupational therapy, and, in children, tutoring may be necessary.

When preparing for appointments, make sure you are aware of any pre-appointment restrictions, such as diet. Write down your symptoms - even things that may seem unrelated. Write down any recent life changes or major stressors. Make a list of your medications and any other supplements. Write down the questions you have and bring a friend or relative along with you to help you remember what your doctors say. While each person's prognosis and treatment can differ greatly, huge strides have been made in the field overall. And our understanding continues to grow, giving your expert medical team an ever-expanding set of tools to help you navigate this difficult journey as you maintain a manageable and positive quality of life. If you'd like to learn even more about brain tumors, watch our other related videos, or visit mayoclinic.org. We wish you well.

A brain tumor is a mass or growth of abnormal cells in your brain.

Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your brain (primary brain tumors), or cancer can begin in other parts of your body and spread to your brain as secondary (metastatic) brain tumors.

How quickly a brain tumor grows can vary greatly. The growth rate as well as the location of a brain tumor determines how it will affect the function of your nervous system.

Brain tumor treatment options depend on the type of brain tumor you have, as well as its size and location.



The signs and symptoms of a brain tumor vary greatly and depend on the brain tumor's size, location and rate of growth.

General signs and symptoms caused by brain tumors may include:

  • New onset or change in pattern of headaches
  • Headaches that gradually become more frequent and more severe
  • Unexplained nausea or vomiting
  • Vision problems, such as blurred vision, double vision or loss of peripheral vision
  • Gradual loss of sensation or movement in an arm or a leg
  • Difficulty with balance
  • Speech difficulties
  • Feeling very tired
  • Confusion in everyday matters
  • Difficulty making decisions
  • Inability to follow simple commands
  • Personality or behavior changes
  • Seizures, especially in someone who doesn't have a history of seizures
  • Hearing problems

When to see a doctor

Make an appointment with your doctor if you have persistent signs and symptoms that concern you.

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Brain tumors that begin in the brain

Primary brain tumors originate in the brain itself or in tissues close to it, such as in the brain-covering membranes (meninges), cranial nerves, pituitary gland or pineal gland.

Primary brain tumors begin when normal cells develop changes (mutations) in their DNA. A cell's DNA contains the instructions that tell a cell what to do. The mutations tell the cells to grow and divide rapidly and to continue living when healthy cells would die. The result is a mass of abnormal cells, which forms a tumor.

In adults, primary brain tumors are much less common than are secondary brain tumors, in which cancer begins elsewhere and spreads to the brain.

Many different types of primary brain tumors exist. Each gets its name from the type of cells involved. Examples include:

  • Gliomas. These tumors begin in the brain or spinal cord and include astrocytomas, ependymomas, glioblastomas, oligoastrocytomas and oligodendrogliomas.
  • Meningiomas. A meningioma is a tumor that arises from the membranes that surround your brain and spinal cord (meninges). Most meningiomas are noncancerous.
  • Acoustic neuromas (schwannomas). These are benign tumors that develop on the nerves that control balance and hearing leading from your inner ear to your brain.
  • Pituitary adenomas. These are tumors that develop in the pituitary gland at the base of the brain. These tumors can affect the pituitary hormones with effects throughout the body.
  • Medulloblastomas. These cancerous brain tumors are most common in children, though they can occur at any age. A medulloblastoma starts in the lower back part of the brain and tends to spread through the spinal fluid.
  • Germ cell tumors. Germ cell tumors may develop during childhood where the testicles or ovaries will form. But sometimes germ cell tumors affect other parts of the body, such as the brain.
  • Craniopharyngiomas. These rare tumors start near the brain's pituitary gland, which secretes hormones that control many body functions. As the craniopharyngioma slowly grows, it can affect the pituitary gland and other structures near the brain.

Cancer that begins elsewhere and spreads to the brain

Secondary (metastatic) brain tumors are tumors that result from cancer that starts elsewhere in your body and then spreads (metastasizes) to your brain.

Secondary brain tumors most often occur in people who have a history of cancer. Rarely, a metastatic brain tumor may be the first sign of cancer that began elsewhere in your body.

In adults, secondary brain tumors are far more common than are primary brain tumors.

Any cancer can spread to the brain, but common types include:

  • Breast cancer
  • Colon cancer
  • Kidney cancer
  • Lung cancer
  • Melanoma

Risk factors

In most people with primary brain tumors, the cause of the tumor isn't clear. But doctors have identified some factors that may increase your risk of a brain tumor.

Risk factors include:

  • Exposure to radiation. People who have been exposed to a type of radiation called ionizing radiation have an increased risk of brain tumor. Examples of ionizing radiation include radiation therapy used to treat cancer and radiation exposure caused by atomic bombs.
  • Family history of brain tumors. A small portion of brain tumors occurs in people with a family history of brain tumors or a family history of genetic syndromes that increase the risk of brain tumors.

Brain tumor care at Mayo Clinic

Aug. 06, 2021
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