If your primary care doctor suspects you have a brain tumor, you may be referred to a specialist who is trained in treating brain and nervous system disorders (neurologist). Your doctor may recommend a number of tests and procedures, including:
- A neurological exam. During a neurological exam, your doctor may check your vision, hearing, balance, coordination, strength and reflexes. Problems in one or more of these areas may provide clues about the part of your brain that could be affected by a brain tumor.
Imaging tests. Magnetic resonance imaging (MRI) is often used to help diagnose brain tumors. In some cases, a dye (contrast material) may be injected through a vein in your arm during your MRI study to help show differences in brain tissue.
A number of specialized MRI scan components — including functional MRI, perfusion MRI and magnetic resonance spectroscopy — may help your doctor evaluate the tumor and plan treatment.
Other imaging tests may include computerized tomography (CT) scan and positron emission tomography (PET).
Brain MRI scan
- Tests to find cancer in other parts of your body. To rule out other types of brain tumors that may have spread from other parts of the body, your doctor may recommend tests and procedures to determine where the cancer originated. Gliomas originate within the brain and are not the result of cancer that has spread (metastasized) from elsewhere.
Collecting and testing a sample of abnormal tissue (biopsy). Depending on the location of the glioma, a biopsy may be performed with a needle before treatment or as part of an operation to remove the brain tumor.
A stereotactic needle biopsy may be done for gliomas in hard-to-reach areas or very sensitive areas within your brain that might be damaged by a more extensive operation. During a stereotactic needle biopsy, your neurosurgeon drills a small hole into your skull. A thin needle is then inserted through the hole. Tissue is removed through the needle, which is frequently guided by CT or MRI scanning.
The biopsy sample is then analyzed under a microscope to determine if it's cancerous or benign.
A biopsy is the only way to definitively diagnose a brain tumor and give a prognosis to guide treatment decisions. Based on this information, a pathologist can determine the grade or stage of a brain tumor.
Tumors are divided into four grades with grade I tumors having the slowest growing, most benign cells and grade IV tumors having the most abnormal and aggressive cancer cells.
April 08, 2015
- Central nervous system cancers. Fort Washington, Pa.: National Comprehensive Cancer Network. http://www.nccn.org/professionals/physician_gls/f_guidelines.asp. Accessed April 29, 2014.
- Winn RH. Youmans Neurological Surgery. 6th ed. Philadelphia, Pa.: Saunders Elsevier; 2011. http://www.clinicalkey.com. Accessed April 29, 2014.
- Stupp R, et al. High-grade malignant glioma: ESMO clinical practice guidelines for diagnosis, treatment and follow-up. Annals of Oncology. 2010;21:v190. http://annonc.oxfordjournals.org/content/21/suppl_5/v190.full.pdf+html. Accessed Nov. 4, 2014.
- Brain SPOREs. National Institutes of Health. http://trp.cancer.gov/spores/brain.htm. Accessed April 29, 2014.
- Moynihan TJ (expert opinion). Mayo Clinic, Rochester, Minn. May 12, 2014.
- Glioma. American Brain Tumor Association. http://www.abta.org/brain-tumor-information/types-of-tumors/glioma.html. Accessed Nov. 6, 2014.
- Omuro A, et al. Glioblastoma and other malignant gliomas: A clinical review. Journal of the American Medical Association. 2013;310:1842. http://jama.jamanetwork.com/article.aspx?articleid=1764056. Accessed Nov. 4, 2014.
- Astrocystoma. American Brain Tumor Association. http://www.abta.org/brain-tumor-information/types-of-tumors/astrocytoma.html. Accessed Nov. 6, 2014.
- Ependymoma. American Brain Tumor Association. http://www.abta.org/brain-tumor-information/types-of-tumors/ependymoma.html. Accessed Nov. 6, 2014.
- What you need to know about brain tumors. National Cancer Institute. http://www.cancer.gov/cancertopics/wyntk/brain.pdf. Accessed Nov. 6, 2014.
- Armstrong TS, et al. Use of complementary and alternative medical therapy by patients with primary brain tumors. Current Neurology and Neuroscience Reports. 2008;8:264.
- Adult brain tumors treatment (PDQ): Health professional version. National Cancer Institute. http://www.cancer.gov/cancertopics/pdq/treatment/adultbrain/healthprofessional. Accessed Nov. 6, 2014.
- Taylor L. Diagnosis, treatment and prognosis of glioma: Five new things. Neurology: Clinical Practice. 2010:S28. http://www.neurology.org/content/75/18_Supplement_1/S28.full. Accessed Nov. 4, 2014.
- Rice EM. Decision Support System. Mayo Clinic, Rochester, Minn. Jan. 20, 2015.
You Are ... The Campaign for Mayo Clinic
Mayo Clinic is a not-for-profit organization. Make a difference today.