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This is a structured glossary of words and terms you may come across in your records that need explanation. This is not an exhaustive list – some words will be missing. If something you’re looking for isn’t here, or you need more help with some of these words then call or email brainstrust on 01983 292 405 or You can also Suggest a word.

1p19q A chromosome. If the chromosome 1p19q is showing deletion from an oligodendroglioma it means that the tumour is more responsive to chemotherapy.
Adjuvant Usually used as ‘adjuvant therapies’. These are treatments which are given after a primary treatment, e.g. after removal of a brain tumour
Alkylating agents A family of anticancer drugs that interfere with a cell’s DNA to stop it growing
Anaplastic When cells divide rapidly and bear little or no resemblance to normal cells in appearance or function.
Anterior Placed before or in front
Anti-angiogenic therapy Treatment which blocks the formation of new blood vessels around a tumour
Antibody An antibody is a protein made by the white blood cells to combat foreign substances
Antigens Any substance capable of inducing a specific immune response and of reacting with the products of that response
Artifact Fuzziness or distortion in an image caused by manipulation, such as file compression
Astrocytes A large, star-shaped cell that forms a supportive network for brain tumour tissue
Asymptomatic If you are asymptomatic it means you don’t have any symptoms
Avastin (Bevacizumab) A monoclonal antibody that interferes with the blood supply to a brain tumour. It blocks the formation of new blood vessels
Awake craniotomy Neurosurgery done with the patient awake for all or part of the surgery
Axial Perpendicular to the long axis of the body
Axial (intra and extra) Axial is the position as it relates to the central nervous system (CNS). Intra-axial is within the CNS; extra-axial is outside the CNS
Benign Usually slow growing, less tendency to invade and often curable if completely removed
Biopsy A medical test performed by a surgeon or an interventional radiologist who will take a sample of cells or tissues for examination
Biopsy only A surgical procedure to remove a small piece of tumour for examination to make a diagnosis. This is not performed as part of the surgery to remove the tumour but is a separate procedure
Blood brain barrier (BBB) A barrier between brain tissue and circulating blood. It is there to protect the brain and prevents substances from leaving the blood and crossing into the brain tissues
Brain shift Deformation and shift of brain tissue during neurosurgery
Brain stem The bottom portion of the brain, which connects the cerebrum to the spinal chord
Burr hole A hole made in the skull by a special drill with a rounded tip
Calcification Deposits of calcium in the tissues
Cannula A thin tube inserted into a vein or body cavity to administer medicine, drain off fluid, or insert a surgical instrument
Carmustine (BCNU) A chemotherapy agent used to treat brain tumours
Caudal Postioned underneath or toward the bottom. Sometimes referred to as inferior
Cell The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane.
Cellular packing density A large collection of non-overlapping solid objects (particles) is called a packing. They are useful models for the structures of brain tumours. The packing density is defined as the fraction of space covered by the particles. This can be used to model the growth of a brain tumour.
Cerebellum The second largest structure of the brain, the cerebellum is located just above the neck in the back of the head
Cerebrum The largest area of the brain, which occupies the uppermost part of the skull. It consists of two halves (hemispheres)
cGy (centiGrays) A unit of absorbed radiation dose equal to one hundredth
Chemosensitive The susceptibility of tumour cells to the cell-killing effects of anticancer drugs
Chemotherapy Drug therapy for cancer
Chromatin The protein structures that package DNA and regulate its function, in cancer stem cells
Chromosome Part of a cell that contains genetic information
Clinical presentation The picture of signs and symptoms, which leads to a diagnosis
Coarse Thick, rough appearance. This can be used to describe the abnormal chromatin in tumour nuclei
Concomitant Happening at the same time e.g. concomitant temodal with radiotherapy
Concurrent Happening at the same time. Radiotherapy and chemotherapy are often referred to as concurrent when they are given at the same time.
Conformal Radiotherapy beams are shaped in three dimensions to match the shape of the tumour
Contrast 1) The degree to which light and dark areas of an image differ in brightness or in optical density.


2) A contrast agent is a substance injected into the body that illuminates certain structures that would otherwise be hard to see on the radiograph (film).

Coronal The plane created by an imaginary line that divides the body at any level into anterior and posterior portions. Also called the frontal plane.
Corpus Callosum Nerve fibres that pass through and connect the two halves of cerebral hemispheres
Cortex The outer layer of the brain
Cortical mapping Cortical maps identify the language, motor, and sensory areas of the cortex and are often used during brain surgery
Craniocaudal The direction of entry of the x-ray beam. The beam enters at the cranial end of the part being examined and exits at the caudal end
Cranium The top portion of the skull
CSF (cerebrospinal fluid) A watery fluid that is continuously produced and absorbed and that flows in the ventricles within the brain and around the surface of the brain and spinal cord
CT (computerised tomography) X rays are aimed at slices of the body (by rotating equipment) and the results are assembled with a computer to give a three-dimensional picture of a structure
Cyberknife® Brand name of a machine used to deliver linear accelerator stereotactic radiosurgery
Cyst A cyst in the brain is a sphere filled with fluid, similar to a miniature balloon filled with water. Cysts may contain fluid, blood, minerals, or tissue.
Cystic A cyst in the brain is a sphere filled with fluid, similar to a miniature balloon filled with water. Cysts may contain fluid, blood, minerals, or tissue. If a tumour has cystic components then it may contain some of these things.
Cytoplasm The fluid inside a cell but outside the cell’s nucleus. Most chemical reactions in a cell take place in the cytoplasm.
Cytostatic An agent that stops cell growth or division
Debulking A surgical procedure to reduce the size of a brain tumour by removing a portion of it
Delineation The outline of the tumour. Also used to delineate target volume of tumour for surgery and radiotherapy
Demyelination Loss of the myelin sheath of a nerve
Dexamethasone A corticosteroid drug used to treat inflammation
Diffuse Widely spread; not confined or localised
Dis-cohesive Cells that do not stick to each other
Dose The total amount of ionizing radiation absorbed by material or tissues, expressed in centigrays
Dose rate The quantity of a treatment given over a period of time
DTI (diffusion tensor imaging) A refinement of magnetic resonance imaging (MRI) that allows the doctor to measure the flow of water and track the pathways of white matter in the brain. DTI is able to detect abnormalities in the brain that do not show up on standard MRI scans.
Dura The outermost of the three meninges
EEG (electroencephalogram) A record of the tiny electrical impulses produced by the brain’s activity. By measuring characteristic wave patterns, the EEG can help diagnose certain conditions of the brain.
Eloquent Used to describe an area of the brain where, if it is damaged or removed, will result in loss of sensory processing or linguistic ability
End of life A phrase used to describe a phase of illness which has become advanced, progressive and incurable
Endocrine system The tissues or glands in the body that secrete hormones
Endothelial The main type of cell found in the inside lining of blood vessels in the brain
Enhancement A substance is used to enhance the structures within the brain during a scan. This reduces the lowest grey values to black and the highest to white.
Eosinophilic Staining a cell or tissue with the pink dye eosin. This is characteristic of many of the low grade glial tumours.
Ependymal A cell that forms the lining of the fluid-filled spaces in the brain and spinal cord. It is a type of glial cell.
Excision A cut
External Beam Radiation therapy that uses a machine to aim x rays at a brain tumour
Fibrillary Made up of minute fibres
First line management Initial treatment of an illness
FLAIR (Fluid attenuated inversion recovery) A pulse sequence used in scanning to null signal from fluids. For example, it can be used in brain imaging to suppress cerebrospinal fluid (CSF).
fMRI (functional MRI) Functional MRI takes the map obtained with traditional MRI imaging, and adds on additional dimensions, such as measuring regional blood flow over time, or something about the biochemistry of tissue of a brain tumour in a specified location in the brain
Focal Limited to a specific area
Foci Foci is the plural of focus.It suggests microscopic visualisation of the tumor cells. Under a microscope therefore you might see more than one indication of one or two microscopic foci of possible invasion.
Fractionated Dividing the total dose of radiation to be given into several smaller, equal portions delivered over a period of days
Gadolinium A substance that enhances tumour images using magnetic resonance imaging (MRI).
Gamma Knife ® Brand name of a machine used to deliver stereotactic radiosurgery (SRS), a focal form of radiation therapy
GFAP Short for Glial Fabrillary Acidic Protein. This is a gene. It provides instructions for making GFAP protein, a member of the family that provides support and strength to cells.
Gliadel ® The brand name of a wafer used to deliver chemotherapy
Glial cells Any of the cells that hold nerve cells in place and help them work the way they should. The types of glial cells include oligodendrocytes, astrocytes, microglia, and ependymal cells. Also called neuroglia.
Gliolan/5 ALA ® Gliolan is a powder to be made up into a solution to be taken by mouth. Gliolan is used in adult patients with malignant glioma. It helps surgeons to see the tumour more clearly during an operation to remove it from the brain
Global Throughout the brain
Grade A brain tumour will be given a grade which refers to the way the cells of the tumour look under a microscope. Grade 1 (low grade) refers to tumours that appear less likely to spread and grade IV (high grade) refer to tumours that appear to grow more quickly, or are most malignant. The brain tumour will be graded according to the highest grade of cell that the pathologist sees in the biopsy specimen. So if the tumour has a high percentage of grade II cells, and a small percentage of grade III cells, the tumour will be graded as a grade III.
Gross total resection Removal of all the tumour
Halo An area of perinuclear clearing
Heterogeneity A state of having different characteristics and qualities
Heterogeneous A state of having different characteristics and qualities
High grade Tumours that appear to grow more quickly, or are most malignant
Histology The study of tumour cells under a microscope
Histopathology The study of diseased tissues at a minute (microscopic) level
Homogeneous Of a uniform, consistent nature
Hydrocephalus An abnormal buildup of cerebrospinal fluid (CSF) in the ventricles of the brain
Hyperchromatic Abnormally highly coloured or excessively stained
Hyperostosis An excessive growth of bone
Hypothalamus The region of the brain that forms part of the wall of the third ventricle. It is part of the endocrine system.
IDH-1 Short for Isocitrate Dehydrogenase. IDH is an enzyme, one form of which participates in the citric acid cycle
Image guidance A surgical procedure where the surgeon uses tracked surgical instruments to indirectly guide the procedure
Imaging The use of technology to create a picture of the brain e.g. MRI scan
Immunocytochemistry Technique which uses specific antibodies to identify and stain tissue
Immunohistochemistry (IHC) The process of detecting antigens or biological markers within tumours or brain tissue using antibodies. Immunohistochemistry provides insight about the classification of brain tumours by identifying cellular markers of phenotype and about the tumour’s potential to grow.
Immunoreactive Reacts with an antibody
iMRI Intraoperative magnetic resonance imaging. iMRI enables neurosurgeons to obtain detailed images of the brain during and immediately after surgery, while the patient is still in the operating room
IMRT (intensity modulated radiation therapy) Specialised equipment that shapes radiation beams to the size and shape of the tumour
Increased (high) signal Hyperintensity signals show up as increased brightness (white) on MRI using different scanning techniques. The nature of brain scans causes tissues with more water to give off brighter signals that appear whiter on the scans.
Inflammation Swollen brain tissue
Infra-tentorial Below the tentorium
Intracranial Inside the cranium
Intracranial haemorrhage Bleeding within the skull
Intracranial pressure (ICP) Pressure inside the cranium
Intravenous Into the vein
Intrinsic Originating from, or situated within, an organ or tissue
Isotope A form of a chemical element that has a different-from-normal atomic mass. Isotopes are used in a number of medical tests because they can produce images of tissues that can be used to detect diseases or conditions.
Ki67 An antigen that detects cells in synthesis phase (the period when the chromosomes are replicated).
Late effects A health problem that occurs months or years after a disease is diagnosed or after treatment has ended
Laterality The side of the body in which symptoms are showing
Lesion A brain lesion describes damage or destruction to any part of the brain. It may be due to trauma or any other disease that can cause inflammation, malfunction, or destruction of a brain cells or brain tissue
Leukopenia A reduction in the number of white cells in the blood
LINAC (linear accelerator) An electrical device that creates ionising radiation in the form of x-rays (photons)
Lobe One of four sections of the cerebral hemispheres
Localised Confined or restricted to an area
Lomustine (CCNU) A chemotherapy agent used to treat brain tumours
Low grade Tumours that appear less likely to spread
Macroscopy Examination with the naked eye
Malignant Cancerous, tending to invade normal tissue or to recur after removal
Margin A border or edge of the tumour
Markers Pathologists can test for markers in the tumour tissue. Markers can be genetic, molecular or immunohistochemistry. These tests can:
Mask A mould to keep your head from moving so that you are in the exact same position for each treatment
MDT Multidisciplinary team meeting
Median survival Average survival time for patients with a certain tumour. 50% will survive longer than the median survival and 50% will survive less.
Meninges A membrane (one of 3) that envelops the brain and spinal cord)
Metabolism The chemical and physical processes that happen to maintain the body and produce energy
Metastasis/metastases Spread to another part of the body, usually through blood vessels, lymph channels or spinal fluid.
Metastatic brain tumour A secondary brain tumour formed of cancer cells that began elsewhere in the body e.g. lung, breast, colon, kidney, skin
MGMT Abbreviation for 06-methylguanine –DNA methyltransferase, a gene thought to play a role in DNA repair
MIB1 A gene that regulates cell death (apoptosis)
Micro-calcification A tiny abnormal deposit of calcium salts
Microvascular proliferation Abnormally thickened blood vessels which tend to be seen in higher grade gliomas. They tend to be leaky and cause contrast enhancement on imaging
Midline An imaginary line running along the surface of the brain (front to back), which separates the right and left hemispheres
Mitoses The number of cells dividing
Modality A method of treatment
Molecular analysis The analysis of human DNA, RNA, and chromosomes to establish a diagnosis or prognosis
Monoclonal Deriving from a single cell
Morphology The form and structure e.g. of a tumour
Motor Movement, control of muscles
MRI (magnetic resonance imaging) A special radiology technique which takes pictures of internal structures of the body using magnetism, radio waves, and a computer to produce the images of body structures
Multifocal Having many focal points. Damage caused by the disease occurs at multiple sites
Multinucleated Having more than one nucleus per cell
Myelin sheath The insulating envelope of myelin that surrounds the core of a nerve fibre. It facilitates the transmission of nerve impulses.
Myelosuppression A decline or absence of blood cell production
Necrosis Dead cells in tissue
Neoplasm A tumour, either benign or malignant
Neoplastic Used to describe abnormal new growth of tissue
Neuro-oncology The branch of medical science dealing with tumours of the nervous system
Neuroendoscope An endoscope for examining and performing various interventions in the central nervous system
Neuroendoscopy The use of a neuroendoscope with the aid of a neuronavigation system to examine the central nervous system and perform minimally invasive neurosurgical procedures.
Neurofibrillary matrix Extracellular background in which the cell sits
Neuronavigation Pre-operative MRI information, fed into a computer, that allows the surgeon to view 3D images during surgery
Neuropathology The study of diseases of the nervous system, which includes the brain
Neurotoxicity Damage to the nervous system
Neutropenia An abnormal decrease in the number of neutrophils, a type of white blood cells
Nitrosureas A group of anticancer drugs able to cross the blood brain barrier
Nuclear Forming a nucleus
Nucleus The structure in a cell that contains the chromosomes
Occipital lobe The lobe of the cerebral hemispheres at the back of the head, just above the neck
Oedema Swelling caused by fluid
Oligodendrocytes Cells that cover and protect nerve cells in the brain and spinal cord
Oligodendroglial Describes a slow-growing tumor that begins in oligodendrocytes.
Optimal Most desirable or satisfactory
Oral By mouth
Overall survival (OS) The percentage of people in a study or treatment group who are still alive for a certain period of time after they were diagnosed with or started treatment for a disease
Palisading The lining up of cells which gives them the ordered appearance of a fence
Palliative Therapy with the goal of relieving symptoms and improving quality of life
Palliative radiation Radiation therapy with a goal of relieving symptoms and improving quality of life
Paraffin Used in tissue preparation and processing
Parietal lobe One of the four lobes of the cerebral hemisphere
Partial Not total. Some tumour could not be removed
Pathology The branch of medicine that looks at abnormal changes in cells and tissues which signal disease
PCV regimen (procarbazine, lomustine (CCNU), vincristine) A combination chemotherapy regimen
Perfusion MR A special type of MRI that uses an injected dye in order to see blood flow through tissues
Perinuclear Situated around a nucleus
PET (position emission topography) A scanning device which uses low dose radioactive sugar to measure brain activity
Pleomorphic Varying in cell shape
Posterior Back
Prognosis A forecast as to likely outcome, the chance of recovery
Progression free survival (PFS) The length of time during and after the treatment of a disease that a patient lives with the disease but it does not get worse.
Proliferation The growth and reproduction of similar cells.
Prophylaxis Preventative
Proton beam A treatment that uses high energy beams to treat tumours
Pseudoprogression Swelling or contrast enhancement on a scan which suggests tumour progression or recurrence, when it is treatment effect. Pseudoprogression can stabilise without additional treatments and often remains clinically asymptomatic
R132H The most common point mutation of IDH1.This mutation is more commonly seen in lower grade gliomas and the higher grade gliomas that derive from them
Radiation oncology The use of radioactive substances and x-rays for the treatment of brain tumours
Radiosurgery A special form of radiation therapy that uses a large number of narrow, precisely aimed, high dose beams of ionising radiation
Radiotherapy A treatment in which high-energy rays are used to damage cancer cells and stop them from growing and dividing
Regime A regulated system of treatment
Resection Surgical removal of a brain tumour
Saggital The front to rear plane of the body (chest to back)
Segmental Made up of segments
Shunt A drainage system inserted in the brain to drain fluid from a ventricle into a body cavity
Signal Brightness of a tissue or structure on MRI
Single agents Treatment with a single chemotherapy agent; i.e., treatment with one type of chemotherapy drug, rather than with a combination of different chemotherapy drugs
Sonowand ® Technology which enables the surgeon to update the map during surgery, scanning the brain with real time 3D ultrasound.
Specimen A sample of tissue, blood, or urine which is used for analysis and diagnosis
SPECT (single photon emission computed tomography) A scanning technique which uses radioactive materials
Stereotactic Precise positioning in a 3D space
Stereotactic biopsy A biopsy accomplished with a computer guided needle
Stereotactic radiosurgery (SRS) A form of radiation therapy that focuses high-powered x-rays on a small area of the body, better targeting the abnormal area. It is a treatment, not a surgical procedure. Some types of stereotactic radiosurgery require a specially fitted face mask or a frame attached to your scalp
Steroid Medication used to reduce swelling and inflammation around a brain tumour
Sub-total resection Less than total surgical removal of a tumour
Subcortical The region of the brain below the cortex
Supra-tentorial Above the tentorium
Suture A stitch
Systemic Affecting or circulating throughout the body
T1 weighting MRI image showing structures; cerebrospinal fluid appears black on the image
T2 weighting MRI image showing water; oedema and cerebrospinal fluid appear white on the image
Temozolomide (TMZ) An anti cancer drug that belongs to the family of drugs called alkylating agents
Temporal lobe One of the four lobes of the cerebral hemisphere
Tentorium A flap of the meninges separating the cerebral hemispheres from the brain structures
Thalamus The area surrounding the third ventricle
Thrombocytopenia A decrease in the normal number of platelets in the blood
Tissue A group or layer of cells that work together to perform a specific function
Toxicity State of being poisonous
Trajectory A chosen course
Tumour progression When a tumour recurs, or begins to grow again. The second stage of tumour development
Vascular Relating to the blood vessels of the body
Vascularity The blood supply of a tumour
Ventricles Four connected cavities in the brain through which cerebrospinal fluid flows
WBRT (whole brain radiotherapy) A type of external beam radiotherapy which is given to the whole brain over a period of weeks.
WHO classification The World Health Organisation (WHO) classification for the grading of brain tumours

– aid the diagnosis of brain tumours which are sometimes hard to diagnose
– allow clinicians to work out a prognosis
– indicate whether a tumour will respond to a specific type of treatment.


Summary of data held in brain tumour registry (BTR) records
Abrey and Mason (2009) Brain Tumors Fast Facts: Health Press
Nordon, Reardon and Wen (2011) Primary Central Nervous System Tumors: pathogenesis and therapy: Humana Press
Young, B. Stewart, W. O’Dowd, G. (2011) Wheater’s Basic Pathology: a text, atlas and review of histopathology: Churchill Livingstone Elsevier
Consultant Neuropathologist
Consultant Neurosurgeon
Brain Tumor: dictionary (2010) American Brain Tumor Association