Brain Tumor Glossary of Terms

Easily explore the meaning of hundreds of medical terms or words, many directly used in brain tumor-related terminology.

Basal ganglia

The basal ganglia (or basal nuclei) are a group of nuclei in the brain interconnected with the cerebral cortex, thalamus and brainstem. Basal ganglia are associated with a variety of functions: motor control, cognition, emotions, and learning.


An initial measurement that is taken at an early time point to represent a beginning condition, and is used for comparison over time to look for changes. For example, the size of a tumor will be measured before treatment (baseline) and then afterwards to see if the treatment had an effect.


Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body. Also called non-malignant.

Benign Brain Tumor

Benign brain tumors have defined borders and are composed of harmless cells that usually can be entirely removed. The cells do not invade nearby tissues, but can place pressure on sensitive areas, causing severe pain, brain damage or even be life-threatening.
* When removed, benign brain tumors seldom return
* Benign tumors can turn into malignant tumors

Benign Tumor

A growth that is not cancer. It does not invade nearby tissue or spread to other parts of the body.


A drug used to treat several types of cancer, including certain types of colorectal, lung, and breast cancers and glioblastoma. It is also being studied in the treatment of other types of cancer. Bevacizumab binds to vascular endothelial growth factor (VEGF) and may prevent the growth of new blood vessels that tumors need to grow. It is a type of antiangiogenesis agent and a type of monoclonal antibody. Also called Avastin.


The science of using computers, databases, and math to organize and analyze large amounts of biological, medical, and health information. Information may come from many sources, including patient statistics, tissue specimens, genetics research, and clinical trials.


A biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease. A biomarker may be used to see how well the body responds to a treatment for a disease or condition. Also called molecular marker and signature molecule.


Several of the tests can suggest the presence of a tumor, but the biopsy, which is a piece of the tumor, provides the definitive diagnosis. Depending on the tumor, the biopsy also reveals the type and grade of the tumor and assists in potential treatment. The sample tumor is analyzed by a pathologist, a doctor specializing in tissue, cell and organ evaluation to diagnose disease.

Biopsy Specimen

Tissue removed from the body and examined under a microscope to determine whether disease is present.


A facility that collects, catalogs, and stores samples of biological material, such as urine, blood, tissue, cells, DNA, RNA, and protein, from humans, animals, or plants for laboratory research. If the samples are from people, medical information may also be stored along with a written consent to use the samples in laboratory studies.


Samples of material, such as urine, blood, tissue, cells, DNA, RNA, and protein from humans, animals, or plants. Biospecimens are stored in a biorepository and are used for laboratory research. If the samples are from people, medical information may also be stored along with a written consent to use the samples in laboratory studies.


The science of collecting and analyzing biologic or health data using statistical methods. Biostatistics may be used to help learn the possible causes of a cancer or how often a cancer occurs in a certain group of people. Also called biometrics and biometry.


Internal radiation therapy using an implant of radioactive material placed directly into or near the tumor.

Brain cancer

Brain cancer is the abnormal growth of tissue found inside the skull. There are two types of malignant brain tumors: A primary brain tumor is that which originates in the brain. A metastatic (secondary) brain tumor occurs when cancer cells from other parts of the body - such as the lungs, kidneys, breasts and skin - spread to the brain.

Brain Metastasis

Cancer that has spread from the original (primary) tumor to the brain.

Brain shunt

Surgical establishment of a shunt to drain cerebrospinal fluid (as in hydrocephalus) from a ventricle of the brain to the right atrium

Brain Stem

The part of the brain that is connected to the spinal cord.

Brain stem glioma

Brain stem gliomas are tumors located in the area of the brain called the brain stem, which connects the spinal cord with the brain and is located in the lowest portion of the brain, just above the back of the neck. It can be a low-grade or high-grade tumor, but the most common type is a diffuse intrinsic pontine glioma, which affects the pons portion of the brain stem and stymies nervous system functions. Also:

* Because of tumor location, it causes a challenge in treatment
* Gliomas are the most common form of brain cancer, accounting for about 50 percent of malignant brain tumors
* Occurs most often in children between age 3 and 10, but can occur in adults
* Rarely spreads or metastasizes

Peak incidence occurs from age 6 to 9 with brain stem tumors accounting for 10 to 15 percent of childhood brain tumors. The annual U.S. incidence rate of gliomas: seven per 100,000.

Brain Stem Tumor

A tumor in the part of the brain that connects to the spinal cord (the brain stem).

Brain tumor

A tumor in the brain. There are too many to generalize to just brain tumor. There are many different types and locations.

Brain tumor symptoms

Some of the symptoms may include headache, blurred vision, vomiting, mental dulling, seizures. Localizing signs of brain dysfunction can occur when vital areas of the brain that regulate specific functions such as language or motor control are affected.

Butterfly glioma astrocytoma

Butterfly glioma. Butterfly refers to the anatomical aspect of the tumor. A "butterfly" glioma (of any grade or type) is one which crosses the corpus callosum from one side to the other and then grows out into the hemisphere on both sides. Robert A. Fink, M. D., F.A.C.S., P. C.