Brain and spinal cord tumors are usually found because of signs or symptoms a person is having. If a tumor is suspected, tests will be needed to confirm the diagnosis.

Symptoms of brain and spinal cord tumors

A brain or spinal cord tumor usually comes to light because of the symptoms it causes. Symptoms can be fairly general, or they may be more specific depending on where the tumor is located. Symptoms may occur gradually and become worse over time, or they can happen suddenly, such as with a seizure.

Tumors within any part of the brain may cause pressure to rise within the skull, which can lead to general symptoms such as:

• Headache
• Nausea
• Vomiting
• Blurred vision
• Balance problems
• Personality changes
• Drowsiness

In severe cases, even coma can develop. Headache is a common symptom of a brain tumor, occurring in about half of patients. (Of course, most headaches are not caused by tumors.)

Both brain and spinal cord tumors cause specific symptoms if they irritate or damage certain parts of the brain or spinal cord:

• About half of people with brain tumors will have seizures at some point. The type of seizure may depend on where the tumor is. Sometimes this is the first sign of a brain tumor, but fewer than 1 in 10 first seizures are caused by brain tumors.

• Tumors in parts of the cerebrum (the large, outer part of the brain) that control movement or sensation may cause weakness or numbness of part of the body.

• Tumors in or near the parts of the cerebrum responsible for language may cause problems with speech or even understanding words.

• Tumors in the front part of the cerebrum can sometimes affect thinking and personality.

• Tumors in an area of the brain called the basal ganglia typically cause abnormal movements and an abnormal positioning of the body.

• If the tumor is in the cerebellum, where coordination is controlled, a person may have trouble with walking or other everyday functions, even eating.

• Tumors in the back part of the cerebrum, or around the pituitary gland, the optic nerve, or certain other cranial nerves may cause vision problems.

• Tumors in or near other cranial nerves may lead to loss of hearing, balance problems, weakness of some facial muscles, or trouble swallowing.

• Spinal cord tumors may cause numbness, weakness, or incoordination in the legs, as well as bladder or bowel problems.

The brain controls functions of some other organs, including the production of hormones, so many other symptoms can be caused by brain tumors that haven't been listed here.

Having one or more of the symptoms above does not mean that you definitely have a brain or spinal cord tumor. All of these symptoms may have other causes. Still, if you have symptoms that suggest that a brain or spinal cord tumor may be present, see your doctor so that the cause can be evaluated and treated, if needed.

Medical history and physical exam

If symptoms suggest a CNS tumor may be present, your doctor will take a complete medical history and do a neurologic exam to evaluate brain and spinal cord function. This special type of physical exam may be done by a general doctor. It tests reflexes, muscle strength, eye and mouth movement, coordination, alertness, and other functions.

If the results of the exam are abnormal, your doctor may refer you to a neurologist (a doctor specializing in nervous system diseases) or a neurosurgeon (a surgeon specializing in operations to treat nervous system diseases) to do a more detailed exam or for other tests.

Imaging tests

Your doctor may order one or more imaging tests. These studies use x-rays, strong magnets, or radioactive substances to create pictures of internal organs such as the brain and spinal cord. The tests are viewed and interpreted by radiologists (doctors specializing in x-ray and other diagnostic imaging tests) and by your doctor.

Magnetic resonance imaging (MRI) and computed tomography (CT) scans are used most often for brain diseases. MRI or CT scans will show a brain tumor, if one is present, in almost all cases, and can often tell the doctors exactly where the tumor is in the brain.

Magnetic resonance imaging (MRI) scan

MRI scans are particularly helpful in looking at the brain and spinal cord and are considered the best way to look for tumors in these areas. The images they provide are usually more detailed than those from CT scans (described below). But they do not image the bones of the skull as well as CT scans and therefore may not see the effects of tumors on the skull.

MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of body tissue and by certain diseases. A computer translates the pattern into a very detailed image of parts of the body. A contrast material called gadolinium may be injected into a vein before the scan to better see details.

MRI scans can take a long time -- often up to an hour. You have to lie inside a narrow tube, which can be confining. Newer, more open MRI machines may help with this, but they may provide less detailed images and can't be used in all cases. The machine also makes buzzing and clicking noises that may be disturbing. Some people may need medicine to help them relax for the test.

Magnetic resonance angiography: In some cases, a special form of MRI, known as magnetic resonance angiography or MRA, may be done to look at the structure of the blood vessels in the brain. This can be very useful before surgery to help the surgeon plan an operation.

Magnetic resonance spectroscopy: This test (also known as MR spectroscopy or MRS) is like an MRI, except that the radio wave interactions with different atoms within the tissues are measured. MRS images highlight some features of brain tumors that are not clearly seen by MRI. This may help narrow the possible type of tumor, but in most cases a biopsy of the tumor is still needed to be sure. MRS can also be used after treatment to help determine if an abnormal area is remaining tumor or if it is more likely to be scar tissue.

Magnetic resonance perfusion: For this test, also known as perfusion MRI, a contrast dye is injected quickly into a vein. A special type of MR image is then obtained to look at the amount of blood going through different parts of the brain. Tumors need a bigger blood supply than normal areas of the brain. The faster a tumor is growing, the more blood it needs.

Perfusion MRI can give doctors an idea of how quickly a tumor is growing or help show them the best place to take a biopsy. It can also be used after treatment to help determine if an abnormal area is remaining tumor or if it is more likely to be scar tissue.

Computed tomography (CT) scan

The CT scan is an x-ray test that produces detailed cross-sectional images of your brain and spinal cord (or other parts of the body). Instead of taking one picture, like a regular x-ray, a CT scanner takes many pictures as it rotates around you while you lie on a table. A computer then combines these pictures into images of slices of the body. Unlike a regular x-ray, a CT scan creates detailed images of the soft tissues in the body.

You may get an injection of a contrast dye through an IV (intravenous) line. This helps better outline any tumors that are present. The contrast may cause some flushing (a feeling of warmth, especially in the face). Some people are allergic and get hives. Rarely, people have more serious reactions like trouble breathing or low blood pressure. Be sure to tell the doctor if you have any allergies or if you ever had a reaction to any contrast material used for x-rays.

CT scans take longer than regular x-rays (but not as long as MRI scans). You need to lie still on a table while they are being done. During the test, the table moves in and out of the scanner, a ring-shaped machine that surrounds the table. Some people feel a bit confined by the ring they have to lie in while the pictures are being taken.

Spiral CT (also known as helical CT) is now available in many medical centers. This type of CT scan uses a faster machine. The scanner part of the machine rotates around the body continuously, allowing images to be collected much more quickly than with a standard CT. This lowers the chance of blurred images from body movements. It also lowers the dose of radiation received during the test. The slices it images are also thinner, which yields more detailed pictures.

CT scans are not used as often as MRI scans, but they do have features that make them useful. They may be used in some cases if MRI is not an option (such as in people who are very overweight or people who have a fear of enclosed spaces). CT scans also provide greater detail of the bone structures near the tumor.

CT angiography: For this test, you are injected with a contrast material through an IV line while you are in the CT scanner. The scan creates detailed images of the blood vessels in the brain, which can help doctors plan surgery. CT angiography can provide better details of the blood vessels in and around a tumor than MR angiography in selected cases.

Positron emission tomography (PET) scan

For a PET scan, glucose (a form of sugar) that contains a radioactive atom is injected into the blood. The amount of radioactivity used is very low. Because cancer cells in the body are growing quickly, they absorb larger amounts of the sugar than most other cells. A special camera can then create a picture of areas of radioactivity in the body. The picture is not finely detailed like a CT or MRI scan, but it can provide helpful information about whether abnormal areas seen on other tests (such as MRIs) are likely to be cancerous or not.

This test is also useful after treatment, as it can help tell whether the tumor cells have been killed. (Dead cells do not use glucose.) Abnormal areas may still show up on an MRI scan. PET scans can help determine if the abnormal area is remaining tumor or if it is more likely to just be scar tissue.

Chest x-ray

This is a plain x-ray of your chest, which can be done in a doctor's office, in an outpatient radiology center, or in a hospital. It may be done once a tumor is found in the brain, because most tumors in the brain have actually started in another organ (most often the lung) and spread to the brain.

Angiogram

For this test, a special dye is injected into blood vessels that lead to the region of the tumor, and the area is then viewed with x-rays. This helps doctors look at the blood supply of a tumor.

This test has largely been replaced by other tests that can look at blood vessels in recent years, such as computerized tomographic angiography (CTA) or magnetic resonance angiography (MRA).

Biopsy

Imaging tests such as MRI and CT scans may show an abnormal area that is likely to be a brain tumor. But in most cases these scans cannot give a definite diagnosis of brain cancer. This can only be done by removing some of the tumor tissue, which is called a biopsy.

Once the tissue is removed, it is looked at under a microscope by a pathologist (a doctor specializing in diagnosis of diseases by lab tests) or a neuropathologist (a pathologist specializing in nervous system diseases). The pathologist determines if the tumor is benign or malignant (cancerous) and exactly what type of tumor is present.

In a few instances, the appearance of an astrocytoma on an MRI scan is so characteristic that a biopsy is not needed, especially when the tumor is located in a part of the brain that would make it hard to biopsy (such as the brain stem). In rare cases a PET scan or MR spectroscopy may give enough information so that a biopsy is not needed.

There are 2 main types of biopsies for brain tumors.

Stereotactic (needle) biopsy

This type of biopsy may be used in cases where the risks of surgery might be too high (such as with some tumors in vital areas, those deep within the brain, or other tumors that likely can't be treated with surgery) but where a sample is still needed to make a diagnosis.

The patient may be asleep (under general anesthesia) or awake during the biopsy. If the patient is awake, the neurosurgeon injects a local anesthetic into areas of skin above the skull to numb them. A rigid frame may then be fixed onto the head. This helps make sure the surgeon is targeting the tumor precisely. A cut (incision) is made in the scalp and a small hole is drilled in the skull. An MRI or CT scan is often used along with the frame to help the neurosurgeon guide a hollow needle into the tumor and remove a small piece of tissue. Another approach is to attach markers to the scalp, get an MRI or CT, and then use an image-guidance system to direct the needle into the tumor. This still requires that an incision be made and small hole be drilled into the skull.

The removed tissue is sent to a pathologist, who looks at it under a microscope to determine what type of tumor it is. This information is very important for determining the likely prognosis (outlook) and the best course of treatment.

Surgical or open biopsy (craniotomy)

If the tumor appears to be treatable with surgery based on the imaging tests, the neurosurgeon may not do a needle biopsy. Instead, he or she may do an operation called a craniotomy (described in the section "How are brain and spinal cord tumors treated?") to remove all or most of the tumor. (Removing most of the tumor is known as debulking.)

Small samples of the tumor are immediately looked at by the pathologist while the patient is still in the operating room, to obtain a preliminary diagnosis. This can help guide treatment, including whether further surgery should be done at that time. A final diagnosis is arrived at 3 to 4 days later in most cases.

Lumbar puncture (spinal tap)

This test is used to look for cancer cells in the cerebrospinal fluid (CSF), which is the liquid that surrounds the brain and spinal cord. For this test, you lay on your side on a bed or exam table with your knees up near your chest. The doctor first numbs an area in the lower part of the back near the spine. A small, hollow needle is then placed between the bones of the spine to withdraw some of the fluid.

This fluid is sent to a lab to be looked at under a microscope for cancer cells. Other tests may be done on the fluid as well.

Lumbar punctures are usually very safe, but doctors have to make sure the test does not result in a dramatic change in pressure in the fluid, which could possibly cause serious problems. For this reason, imaging tests such as CT or MRI scans are done beforehand.

Lumbar punctures usually aren't done to diagnose brain tumors, but they may be done after a diagnosis is made for certain types of brain tumors that can commonly spread via the CSF (such as ependymomas). They are particularly important in people with suspected brain lymphomas because often the lymphoma cells spread into the spinal fluid. These lymphomas require extra treatment.

Blood and urine tests

These lab tests are rarely part of the actual diagnosis of brain and spinal cord tumors, but they may be done if you have been sick for some time to check how well the liver, kidneys, and some other organs are working. Routine blood cell counts may also be needed, especially before any planned surgery or if you are getting chemotherapy.

Last Medical Review: 11/12/2009
Last Revised: 11/12/2009