Providing you with the basic information to help you understand brain tumors.
Finding out that you or your loved one have a brain tumor can feel overwhelming. Doctors will perform many tests using medical equipment and terminology you are unfamiliar with. Learning this process can help you feel more comfortable and confident you are making the right medical decisions.
Anatomy
Learn where the tumor is located within the brain to help you understand what symptoms may occur.
Brain Tumor Types
There are more than 120 types of brain tumors. See the most common brain tumor types.
Symptoms
Possible symptoms that can be related to the location of the brain tumor or increased pressure.
Pathology / Grades
See the various tumor grades. Knowing the grade helps to predict the tumor’s likely behavior.
Diagnostic Tests
When a brain tumor is suspected or confirmed, your doctor will have you undergo one or more tests to diagnose or monitor it.
Prognosis
Prognosis refers to the probable outcome of the disease. View the latest prognosis statistical report.
Anatomy
It is important to know where the tumor is located within the brain so you can understand what symptoms or changes may occur.

Changes can be due to the impact of the tumor itself or from treatment.
Address any of these concerns with your health care provider to evaluate if there are options to help alleviate their impact on your quality of life.
Brain Anatomy and Functions
Frontal Lobe
Executive functions including concentration, coordination of thought and activity, judgment, emotional expression, inhibition, coordination of muscle strength and movement, strength on opposite side of body, and understanding scent.
Temporal Lobe
Functions including pain, hunger, “fight or flight” response, short-term memory, emotion, understanding words and directions.
Parietal Lobe
Sensation on opposite side of body, expressive and receptive language comprehension, understanding object’s characteristics (for example, texture and temperature and position in space).
Occipital Lobe
Sight on opposite side, image recognition.
Cerebellum
Balance and coordination of movement of body, arms and legs.
Brain Stem
Regulates heart rate, breathing, blood pressure, swallowing and digestion.
Symptoms
Brain tumors cause a range of symptoms from feeling uncomfortable to life-altering. Symptoms depend on the tumor location, size and growth rate. They can be related to the location of the tumor on the brain (click here to see the brain anatomy and what symptoms may occur), or related to increased pressure. These symptoms can occur gradually over days to months or they can happen suddenly, such as a seizure.
Symptoms that may occur:
- Headaches
- Seizures
- Nausea or vomiting
- Sleepiness or lethargy
- Loss of balance or dizziness
- Convulsions
- Personality or behavior changes
- Memory loss
- Sensory changes
- Changes in sight, speech or hearing
- Weakness or loss of sensation of arms, legs, hands or feet
These symptoms often lead to the diagnosis of your tumor, but may continue to affect your life after diagnosis. Symptoms can also occur if there is growth or recurrence of the tumor. Any symptom you notice should be taken seriously. If your symptom gets worse or a symptom occurs that you have never had before, you should contact your health care team to discuss.
You and your doctor will review your medical history together and he or she will perform a physical exam.
The physical exam tests may include:
- Balance and coordination
- Abstract thinking and memory
- Eye movement
- Sensory perception
- Reflexes
- Control of facial muscles
- Head and tongue movement
If the doctor suspects a brain tumor is present, one or more diagnostic tests will be performed.
Diagnostic Tests
When a brain tumor is suspected or confirmed, your doctor will have you undergo one or more tests to diagnose or monitor it. Tests may also help determine effective treatments. The most effective test to diagnose a brain tumor is an MRI scan. While tests can strongly suggest the presence of a tumor, only a biopsy of suspected tumor tissue that has been surgically removed provides the definitive diagnosis.
MRI
An MRI scan is typically the preferred test for people who may have a brain tumor.
Biopsy
A biopsy is usually done to confirm the diagnosis and determine what type of tumor it is.

Imaging Tests
MRI Scan (Magnetic Resonance Imaging)
An MRI, which uses magnetic fields (not x-rays), provides detailed images of the body and can also measure the tumor’s size. An MRI creates a more detailed picture than a CT scan because the MRI outlines the normal brain structure in unique detail and is the preferred imaging test to diagnose a brain tumor.
This procedure takes about one hour and requires the patient to lie still in a cylinder-type machine. A special dye is given (as a pill or an injection) before the scan to create a clearer picture and distinguish tumors from healthy tissue.
CT Scan (Computed Tomography or CAT Scan)
A CT scan reveals brain abnormalities. This is a sophisticated x-ray machine linked to a computer to create 3-D images. It is painless and can be completed in ten minutes or less. Occasionally, a special dye is injected into the bloodstream to provide more detail. CT scans provide less anatomic detail than an MRI and are typically only used initially or if the patient cannot have an MRI.
Other Tests That May Be Performed
PET Scan (Positron Emission Tomography)
A PET scan may be used to determine brain tumor activity,blood flow, or the effect of the tumor on the brain. A small amount radioactive tracer substance (such as amino acids or sugar) is injected into the bloodstream.
Your doctor can then use a scanner to observe the movement of that substance through the blood and in the brain.
Lumbar puncture (or spinal tap)
A lumbar puncture obtains spinal fluid to determine the presence of tumor cells.
Brain Tumor Types
Primary brain tumors are named according to the type of cells or by the part of the brain where it originates. There are more than 120 different types of brain tumors, making it difficult to find effective treatments.
Most Common Brain Tumor Types In Adults

- Meningioma The tumor grows from the meninges, the layers of tissue covering the brain and spinal cord. As it grows, meningioma compresses other brain tissue, which can affect cranial nerves.
- Glioblastoma (GBM) These are highly malignant (cancerous) tumors that arise from astrocytes (star-shaped glial cells where the tumor originates) or supportive tissue of the brain. They are generally found in the cerebral hemispheres of the brain, but can be found anywhere in the brain or spinal cord.
- Pituitary These tumors develop in the pituitary gland and are called adenomas (benign) or carcinomas (malignant).
- Astrocytoma Astrocytes can develop in any part of the brain or spinal cord. They are star-shaped glial cells where the tumor originates. It can be any grade but in adults, it most often arises in the cerebrum.
- Ependymoma An ependymoma, part of the glial family, is a rare type of primary brain or spinal cord tumor. It originates in the ependyma, the cells that line the passageways in the brain where cerebrospinal fluid is produced.
- Oligodendroglioma The tumor, usually occurring in the cerebrum (located in the upper part of the skull), forms from cells that create the fatty substance that covers and protects nerves. The cerebrum, which is located in the anterior or front portion of the brain, determines personality, intelligence, sensory impulse and motor function.
Pathology / Grades
Following the biopsy lab analysis, your doctor will share the results with you, which will include the type and grade of the tumor. Primary brain tumors are named based on the type of cells they formed in, while the grade of a tumor indicates the difference between slow-growing and fast-growing tumors. Tumor grades are based on how abnormal the cancer cells look under a microscope or by looking at changes in genes or proteins. Knowing the grade helps to predict a tumor’s likely behavior.
- Grade I (low-grade) – The tumor cells look more like normal cells under a microscope and grow and spread more slowly than grade II, III, and IV tumor cells. They rarely spread into nearby tissues. Grade I brain tumors may be cured if they are completely removed by surgery.
- Grade II — The tumor cells grow and spread more slowly than grade III and IV tumor cells. They may spread into nearby tissue and may recur (come back). Some tumors may become a higher-grade tumor.
- Grade III — The tumor cells look very different from normal cells under a microscope and grow more quickly than grade I and II tumor cells. They are likely to spread into nearby tissue.
- Grade IV (high-grade) — The tumor cells do not look like normal cells under a microscope and grow and spread very quickly. There may be areas of dead cells in the tumor. Grade IV tumors usually cannot be cured.
Low-grade tumors can become high-grade tumors. While a tumor may show characteristics from one or more tumor grades, doctors treat patients based on the highest-level tumor grade.
Source: National Cancer Institute
Prognosis
Prognosis refers to the probable outcome of the disease. Some patients want to know their prognosis, while others don’t want to find out. It’s best to talk to your treating physician about your situation. Every person’s situation is different and should be treated individually.
Generally, physicians can’t give their patients a single accurate number for likely disease progression. They must reference one or more clinical trials to obtain their prognosis statistics, and some clinical trials have more detail than others or distinguish different factors. These might include months versus years, overall survival versus progression-free survival, partial resection versus complete resection, age, gender and or tumor grade. Physicians try to combine all the studies and factors to give prognosis, but there is no perfect answer.
Prognosis statistics should be used as a reference, but not a final predictor of your specific case.
Visit the Central Brain Tumor Registry of the U.S. (CBTRUS) for their latest prognosis statistical report.
