Glossary
A B C D E F G H I K L M N O P Q R S T U V W
A
Acoustic neuroma (aka vestibular schwannoma) – These are slow growing tumors that involve the eighth cranial nerve, and over 95% are not malignant. These tumors can be located on both left and right sides in patients with a syndrome called Neurofibromatosis, type II.
Acromegaly – A condition that results from excessive secretion of a chemical, usually from pituitary tumors, called growth hormone. This hormone results in excessive growth of bones and other parts of the body.
Adjuvant treatment – Treatment used following the primary treatment to cure, reduce, or control cancer; for example, chemotherapy and radiation following cancer surgery are adjuvant therapies.
Agnosia – The inability to recognize objects, people, spatial relationships, shapes, or smells. Agnosia(s) can result from injury to the parietal lobe, such as from tumors.
Agraphia – A loss or impairment in the ability to write. This can by a symptom of a tumor in the parietal lobe.
Alkylating agent – Chemotherapy agents that bind to DNA in a special way and damage DNA of cancer cells, resulting in compromised cell division and/or death of cancer cells.
Alopecia – Loss of hair; this can occur on the scalp as a result of some, but not all, types of chemotherapy and external beam radiation therapy.
Anemia – A low amount of red blood cells that can result in excessive fatigue, shortness of breath and pale skin. This can result from bleeding, low dietary iron or as a result of chemotherapy.
Angiogenesis – The formation of new blood vessels; this can occur as a normal bodily function, but new blood vessel formation can also enhance tumor growth. Blood vessels help a tumor defend itself against reduced oxygen delivery and a diminishing supply of nutrients.
Angiogram – A procedure usually performed by a radiologist that uses contrast to visualize the blood vessels in your body, such as in your brain.
Anosmia – The loss of smell that results from damage to nerves going from the nose to the frontal lobes of the brain; the most common type of tumor to do this is a meningioma.
Anterior – The front part of an object of interest, such as a tumor on an MRI brain scan.
Anti-angiogenesis agent – Drugs, therapeutic antibodies, or biological agents that reduce or eliminate new or previously formed blood vessels.
Antibody – A protein that is made from white blood cells to fight infection. Unique antibodies can also be created as pharmaceutical agents to attack tumor cell receptors, proteins produced by cancer cells, or chemicals that result in tumor cell growth.
Antiemetic – A medication that helps prevent or treat vomiting.
Antigen – A signal from a foreign cell that is recognize by a white blood cell and activates the immune system to kill its target. Antigens can also be targets for medical therapies, such as to fight tumors.
Aphasia – The partial or complete loss of speech; this can result from tumors, strokes, or other mechanisms of injury to the brain.
Apoptosis – A special mechanism by which a cell self-destructs or kills itself.
Astrocytoma – A type of primary brain tumor that grows from a support cell in the brain called an astrocyte or their stem cell precursors. Astrocytes help neurons in the brain work faster and more efficiently.
Ataxia – An impairment in the ability to maintain balance or coordination. This can result from tumors, usually in the back part of the brain called the cerebellum.
B
Basal ganglia – A deep part of the brain that serves as a complex regulator of movement; this also contains parts of neurons called axons that are important for sensory and motor function.
Benign – A kind of tumor that typically lacks the invasive properties and unlimited cell replication of a malignant or cancerous tumor.
Bilateral – Something that exists on both sides of an object or organism, such as a tumor being located on both the left and right sides of the brain.
Biological agents or therapies – A type of treatment that involves targeted drugs or stimulants of the immune system used to attack particular chemicals or pathways that a tumor might use to grow.
Biopsy – A method of obtaining tissue that can be accomplished using a special needle or open surgery to take small pieces of tissue from a part of the body in an effort to determine the histological appearance of the tissue and help reach a diagnosis. For example, a biopsy can be used to discover the identity of a brain mass, abnormally enlarged lymph node, or unusual mass in the body itself.
Blood-brain barrier – A term used to explain brain and spinal cord capillaries that restrict passage of proteins and chemicals from blood into brain and spinal cord tissue. The blood-brain barrier (BBB) can also prevent some chemotherapy and antibody drugs from entering the central nervous system.
Bone marrow – The substance found in bones responsible for making important cells in the body, like red blood cells to carry oxygen, white blood cells to fight infection, and platelets to help stop bleeding.
Bone marrow transplant – The infusion of bone marrow back into a patient whose body cannot produce red blood cells, white blood cells or platelets on its own. Bone marrow transplants may be done as part of treatment with high dosages of chemotherapy for certain kinds of tumors in adults and children.
Brainstem – A part of the brain that contains many neurons responsible for a variety of functions, such as eye movements, maintaining breathing, regulating heart function, and swallowing. It also contains neurons that start in the top parts of the brain, called the cerebral cortex, and move down to eventually become the spinal cord. There are three divisions of the brainstem: the midbrain, pons and medulla.
Brainstem glioma – A type of primary brain tumor that is located in the brainstem. Brainstem gliomas can occur in adults and children, but are more frequently seen in children.
C
Calcification – The presence of calcium in certain kinds of brain tumors, such as meningiomas and oligodendrogliomas. It usually indicates a less aggressively behaving tumor.
Cancer – A term used to describe cells that are abnormal and characterized by uncontrolled cell division, local organ invasion and, in many cases, spread to other organs in the body (metastasis). These tumors vary in their level of malignancy and are named, in part, based on the presumed cell of origin and location, such as from the lung, breast, skin or brain.
Carcinogen – A chemical or substance that increases the risk for cancer by virtue of its ability to damage DNA.
Carcinogenesis – The means in which a cell goes from normal to a cancerous cell.
Carcinoma – Another term for cancer, one that usually originates from the lining of skin or other organ system.
Central nervous system (CNS) – A part of the body that contains the brain, brainstem, cerebellum, and spinal cord.
Cerebellopontine angle – This is a part of the brain that is nearby the pons and cerebellum. Tumors like acoustic neuromas are commonly found in this location.
Cerebellum – This is a part of the brain that monitors balance while walking and coordinates movements of the arms and legs. It is located in the back part of the brain, and is connected to the brainstem.
Cerebral cortex or hemispheres – This is the largest part of the brain that contains the frontal, parietal, temporal and occipital lobes, on both the left and right sides. Many neurological functions originate in the cerebral cortex, such as personality, memory, strength, sensation, and vision.
Cerebrospinal fluid (CSF) – Fluid that is produced in the brain and flows around the brain and spinal cord. It is designed to help cushion the brain and spinal cord from the forces of movement, and to also provide an optimal environment for the nervous system to function. The normal appearance of spinal fluid is clear like water.
Chemotherapy – Medical therapies that are designed to damage or kill tumor cells.
Chondroma – A typically slow-growing tumor that originates from cartilage, and is often seen in the skull base.
Chondrosarcoma – An uncommon tumor that originates from cartilage and can undergo malignant transformation from a chondroma. In the nervous system, these are usually found in the base of the skull.
Chordoma – A type of tumor that is generally slow-growing, but can act aggressively around its site of origin, most commonly found in the clivus (base of skull).
Choroid plexus – A tissue composed of special cells and blood vessels that is responsible for making cerebrospinal spinal fluid (CSF) in the central nervous system.
Choroid plexus papilloma – A type of tumor that originates in the choroid plexus, and is a WHO grade 1 tumor. Most are relatively slow-growing and can be found in any location of the brain that contains choroid plexus.
Chromosome – A structure that exists in every cell that contains DNA, and this in turn carries copies of all genes in the human body. There are a total of 46 chromosomes in each cell of the human body.
Clinical trials – Research studies offered to patients with certain medical conditions, such as brain tumors, that evaluate a new form of treatment.
Clivus – A bony structure in the base of the skull in front of the brainstem. Tumors such as chordomas can be found in the clivus.
Congenital – Something that is identified at birth.
Control group – A part of a clinical trial, such as a phase III trial, that uses a known treatment compared to an experimental arm of a trial.
Cranial nerves – A set of 12 neurons that originate in the brainstem, and regulate functions such as taste, hearing, sensation in the face, smell, vision and swallowing.
Craniectomy – A surgical procedure that involves cutting open a hole in the skull to remove a lesion such as a brain tumor.
Craniopharyngioma – A type of brain tumor usually found in the pituitary region that often has cysts and is frequently calcified. It is usually slow-growing.
Craniotomy – A surgical procedure that involves cutting open a hole in the skull for the intent to remove a lesion such as a brain tumor. In most cases, the skull plate or a prosthetic plate is secured over the hole once the surgery is done using a variety of hardware.
CT (computerized tomography) scan – A radiological machine that uses x-rays to obtain pictures of the body, including the brain. It is particularly good at visualizing bone and fresh blood. It is also faster to complete than an MRI, making it ideal in emergent situations.
Cushing's syndrome – A syndrome that typically involves secretion of a hormone that results in a variety of physical problems such as weight gain, a rounded appearance to the face, high blood pressure, high cholesterol, elevated blood sugar, and stretch marks. Common reasons for this include pituitary tumors and tumors that involve the adrenal gland.
Cyst – A mass that is filled with fluid, surrounded by a membranous layer that holds the fluid together.
Cytokines – Proteins that are secreted in your body to stimulate or suppress the immune system.
Cytotoxic – Any substance that can damage or kill a cell; in oncology it generally refers to a drug that damages tumor cells to a greater extent than it damages normal cells in the body.
D
Debulk – A term used to describe surgical removal of a tumor to help reduce pressure from a mass in the brain, and relieve symptoms that may result from it.
Diffuse – A term commonly used to describe a mass or lesion that does not have distinct, clear borders in the brain, usually applicable to interpretation of MRI scans.
Diplopia – Double vision.
DNA (deoxyribonucleic acid) – DNA exists in all cells, and contains all the genetic material necessary to build and repair the human body. All living creatures have DNA, and it serves as the map or set of directions that determines how a person, animal or even plant grows over time.
DNA methylation – A method used by a cell to modify a gene to reduce its expression, and thereby regulate cell growth. One example includes MGMT, which is a DNA repair enzyme that can potentially reverse the effect of Temozolomide chemotherapy. If the gene coding for MGMT is methylated, a tumor cell will not be able to make MGMT, cannot reverse the damage done by an alkylating agent (e.g., temozolomide, CCNU) and, therefore, tumor cells so damaged are more likely to be unable to divide or will die as a result.
Drug resistance – The ability of a tumor cell to overcome damage done by treatment such as chemotherapy or radiation therapy.
Dura matter – The outermost connective tissue layer that covers the brain and spinal cord.
Dysphagia – An impaired ability to swallow solids or liquids. Tumors in the brainstem can result in dysphagia.
E
Edema – Fluid that can build up in tissues, including the brain or spinal cord. Drugs like dexamethasone and bevacizumab can help manage edema in the brain. Other terms like 'swelling' are synonymous with edema.
EGFR (epidermal growth factor receptor) – A receptor found on the cell surface on some tumors that sends a signal to continue growing uncontrollably. This is a target for some drugs like erlotinib (Tarceva).
Emesis – Vomiting.
Enhancement – This is a term used to describe a specific appearance of some tumors on neuroimaging. Contrast is injected in the arm of a patient, and it can go all over the body, including into a tumor that has leaky blood vessels. Contrast helps a tumor stand out on an MRI or CT scan, and also might indicate a more aggressive part of a tumor.
Enzyme – A type of protein produced by cells that help facilitate important functions that keep a patient alive, such as with metabolism or cell division. Enzymes help to start a reaction that leads to production of energy sources in the body, repair mutations in DNA or convert vitamins into building blocks of DNA, for example.
Ependymoma – Tumors that start from cells that make up the inner lining of the brain adjacent to cerebrospinal fluid. These are classified by their histological appearance as ependymoma, anaplastic ependymoma, or myxopapillary ependymoma. They are classified by World Health Organization (WHO) criteria as grade II, III, or IV tumors.
Epidemiological studies – Statistical studies undertaken to evaluate large populations for the frequency and potential source of certain diseases or problems.
Etiology – The cause of a particular disease or problem.
F
Familial – Something that occurs several times in a family, such as certain diseases or tumors.
Focal – Opposite of diffuse. It means a concentrated area with relatively defined margins, rather than a diffusely infiltrative process.
G
Gait – A term for the way a person walks.
Galactorrhea – Inappropriate secretion of milk from breasts that results from chemicals released by pituitary tumors or high estrogen levels.
Ganglioglioma – An uncommon, usually slow-growing tumor that contains a combination of neurons and astrocytes. It is graded as a II or III by WHO criteria.
Ganglioneuroma (also called a gangliocytoma) – This slow-growing, rare tumor contains glial cells and mature neurons. It can occur in either the brain or spinal cord.
Genes – Genes are individual parts of DNA that help to code for certain functions or traits that help us develop in unique ways. For example, genes can help determine eye color or skin tone. Mutations of genes can also lead to cancer, by making a cell unable to stop dividing.
Genetic – A trait or disease that is impacted by genes, or mutations in genes. It also implies an inheritance of normal features or certain kinds of diseases, such as tumors, from one generation to the next.
Gland – An organ that releases hormones, each having a specific purpose to maintain bodily functions. Examples include the pituitary gland and thyroid gland.
Glioblastoma (GBM) – One of the most common primary brain tumors, it is a malignant WHO grade IV tumor.
Glioma – A family of primary brain tumors that arise from support cells in the brain, and include astrocytomas, oligodendrogliomas, or ependymomas. Gliomas can be graded I to IV, based on WHO criteria.
Glucocorticoids (ie steroids) – Medications that are used to reduce swelling in the brain, such as dexamethasone or prednisone. Side effects include insomnia, weight gain, increased appetite, irritability, weakness in lower extremities, and elevated blood sugar.
Grade – The number given to a brain tumor that indicates the potential for further growth, and in general separates low from high grade tumors. Tumors are usually graded according to World Health Organization (WHO) criteria, from I to IV, with I being the lowest grade and IV being the highest grade. Grades I and II are considered low grade, and grades III and IV are considered high grade tumors.
Grand mal seizure – Also referred to as a generalized tonic-clonic seizure, it involves a loss of consciousness and involuntary movements of all extremities. Tongue-biting, drooling and incontinence can occur as a result of a grand mal seizure. Patients are usually tired and confused afterward.
Gray matter – The surface of the brain that contains cell bodies of neurons. Gray matter is where information is generated or stored, and signals are either sent out resulting in neurological actions like movement or speech, or are received that are sensory in nature, such as taste, smell or hearing.
Growth factors – Proteins that are released in your body that help to regulate a variety of functions, such as blood vessel formation or cell growth. Certain growth factors, such as Vascular Endothelial Growth Factor (VEGF) or Epidermal Growth Factor Receptor (EGFR), are of particular interest in the research for glioblastoma brain tumors.
Growth hormone – A hormone released from the pituitary gland that helps promote growth through a variety of actions on bones, muscle and other parts of the human body.
H
Hemangioblastoma – These are tumors that have a lot of blood vessels, are not very common, are slow-growing, can occur in greater frequency in patients with von Hippel-Lindau syndrome, and are found in the brain or spine.
Hemianopsia – The loss of vision in half of the visual field in each eye. Usually the result of damage done to the brain, most commonly in either the temporal or occipital lobes.
Hemiparesis – Weakness but not complete loss of strength on one side of the body, usually from damage to parts of the brain that control strength (ie the motor cortex).
Hemiplegia – Complete loss of function on one side of the body.
Hereditary – A condition that could be passed on from one generation to the next through genes.
Hormone – A chemical that is released from certain organs, such as the pituitary gland, adrenal gland or pancreas, that can affect other organ systems.
Hydrocephalus – A condition that results from the impaired ability to drain spinal fluid from the brain. Fluid filled sacks called lateral ventricles swell up and this can result in symptoms such as headaches, nausea, vomiting, ringing in the ears, problems walking, incontinence and double vision. It can result either from obstruction to flow by, for example, a tumor, or from increased production of spinal fluid.
Hyperthyroidism – Increased production of thyroid hormone that can result rarely from pituitary tumors, or more commonly from problems with the thyroid gland. Symptoms include sweating, irritability, hair loss and weight loss.
Hypothalamus – An organ in the brain that releases hormones, and these regulate the release of hormones from the pituitary gland. The hypothalamus also has important regulatory roles in maintaining appetite, sleep cycles and body temperature.
Hypotonic – Decreased muscle tone.
Hypoxia – Lack of oxygen. Certain kinds of brain tumors, such as glioblastomas, can still grow in hypoxic conditions.
I
Ictal – Related to a seizure.
Immune system – The defense system for your body, it is composed of antibodies and cells called lymphocytes that attack anything perceived as foreign.
Immunotherapy – A form of experimental treatment that attempts to activate or use the immune system to attack certain diseases like cancer.
In vitro – Something made to occur in a laboratory container or controlled environment.
In vivo – Something made to occur in a living organism.
Incidence – The frequency of occurrence for a particular topic of interest, such as brain tumors. In epidemiology, incidence is population-based and is reported as a number per 100,000 population.
Infiltrating – Anything that lacks a defined border and moves throughout a particular region of interest. Certain brain tumors, such as gliomas, are referred to as infiltrative, mainly because its cells can move throughout the brain, in some instances far away from the original tumor site.
Intracellular – Anything that occurs or is located in a cell.
Intracranial – Anything that occurs or is located in the skull.
Intracranial pressure (ICP) – Pressure in the brain. If pressure is too high, symptoms can include headaches, confusion, dizziness, nausea, vomiting or double vision. If pressure is too low, symptoms include headaches or dizziness.
Intramuscular (IM) – Anything located or injected into a muscle.
Intratumoral – Anything located or injected into a tumor.
Intravenous (IV) – Anything that is injected into a vein.
Invasive – A tendency for certain tumors to invade deeply into tissue. This can occur in malignant tumors both inside or outside the central nervous system.
Ipsilateral – Anything that occurs or effects the same side of the body.
K
Karyotype – The chromosomal pattern of a cell.
L
Lateral – A term that refers to a particular side of an object, or a location away from the middle part of an object.
Lethargy – A feeling of being very tired and lacking energy.
Leukocytes – A term referring to white blood cells, which are important parts of the immune system.
Li-Fraumeni syndrome – A rare, inherited syndrome that increases risk for certain kinds of tumors, such as sarcomas, breast cancer and brain tumors.
Ligand – Any molecule that binds to a receptor. Examples include antibodies, hormones or certain drugs.
Limbic system – A part of the brain that is important in regulating memory and emotions.
Linear accelerator (aka linac) – A machine that propels energy particles to a defined target using incrementally increasing amounts of energy or radiation.
Lipoma – A fatty tumor that is generally benign.
Lumbar puncture (LP) (also called a spinal tap) – A procedure that facilitates removal of spinal fluid to either diagnose a condition or for therapeutic purposes. Pressure in the nervous system can also be measured as part of a lumbar puncture. A lumbar puncture can be done as an outpatient, by a variety of physicians, usually neurologists, internal medicine doctors, neurosurgeons or emergency room doctors. Most lumbar punctures take 20-30 minutes and patients usually can go home afterwards.
M
Malignant – More aggressive forms of cancer that can grow quickly and might spread to other parts of an organ system or body.
Medulla oblongata – The lowest part of the brainstem that is connected to the spinal cord. It regulates a variety of neurological functions, such as breathing, heart function and swallowing.
Medulloblastoma – A type of brain tumor that is more commonly seen in children than adults and is located in the cerebellum. It is a WHO grade IV tumor, but can be associated with long-term survival if treated aggressively.
Meninges – These are the coverings of the brain and spinal cord, and are made up of three layers: pia mater, arachnoid and dura mater.
Meningioma – Tumors that grow from coverings of the brain, called meninges. Meningiomas can occur in the brain or spinal cord, and are classified as WHO grade I, II or III tumors, with grade I being the lowest grade and grade III the highest grade. 90% are grade I.
Metastasis – A tumor that has spread from a primary site to a different part of the body.
Metastasize – The act of a tumor spreading to another part of the body.
Metastatic brain tumor – Tumor(s) that spread into the brain, from outside the central nervous system.
MGMT – This stands for methyl-guanine methyl-transferase, an enzyme that helps a tumor cell remove alkylation (methylation) damage from its DNA, and therefore makes a tumor cell more resistant to treatment with alkylating agents like Temodar.
Midbrain – The middle part of the brainstem, between the pons and medulla oblongata. This is important for eye movements and other functions.
Mixed gliomas – These are primary brain tumors that contain mixed elements, such as oligoastrocytomas. They can be low or high-grade.
Morbidity – Side effects or complications of a particular drug, treatment or disease process, such as a brain tumor.
MRI (magnetic resonance imaging) – A machine that uses magnetic energy to form an image of a particular organ system, such as the brain. Generally regarded as low risk, certain situations may preclude having an MRI, such as having metal in your body like a cardiac pacemaker, some artificial joints, or shrapnel in your eyes.
N
Necrosis – Dead cells or tissue, as can occur in certain tumors, such as glioblastomas or metastatic tumors, or as a complication from treatment, such as radiation.
Neo-adjuvant treatment – A term used to refer to chemotherapy or radiation therapy given prior to surgery.
Neoplasm – Another word for a cancer, it is a growth of cells that forms a tumor or mass.
Nervous System – An organ system that contains the brain, spinal cord and peripheral nerves that serve all neurological functions, including personality, strength, sensation, balance, and vision.
Neuro-oncologist – A physician who specializes in the management of tumors in the central nervous system. A neuro-oncologist will design and implement chemotherapy protocols depending on the type of tumor being treated. A neuro-oncologist frequently manages complications of cancer in the nervous system as well, such as seizures, blood clots, fatigue, side effects from steroids and paraneoplastic syndromes. Historically, neuro-oncologists have completed training in neurology or medical oncology prior to their sub-specialization in neuro-oncology.
Neuroblastoma – A type of tumor that is more common in children, and usually arises from nerve cells, such as from the adrenal gland.
Neurofibromatosis type 1 (NF1) – An inherited neurological syndrome that occurs in 1 out of 3000 births, is passed on in a dominant fashion (ie if one parent has NF1, their children have a 50% chance of inheriting it), and can result in many different, complex tumors of the brain, spinal cord and peripheral nerves. The mutation occurs on chromosome 17.
Neurofibromatosis type 2 (NF2) – An inherited neurological syndrome that occurs in 1 out of 25,000 births, is passed on in a dominant fashion, can have many different tumors in the brain, spinal cord and peripheral nerves, and has acoustic neuromas present on the left and right sides of the brain. The mutation occurs on chromosome 22.
Neuron – The major cell type in the brain that is primarily responsible for all elements of neurological function, such as complex thoughts, movement, sensation, balance and vision.
Neuropathy – A term used to describe damage to peripheral nerves that can result in a variety of nerve problems, such as numbness, pain or double vision. Medical problems like diabetes or hypothyroidism can result in neuropathy, as can certain types of cancer like multiple myeloma, and many chemotherapies.
Neuropsychiatrist – A psychiatrist with special training and interest in managing patients with neurological problems, such as brain tumors.
Neuropsychological testing – Complex tests carried out by neuropsychologists that help to identify problems with decision-making, managing tasks and memory that can be a common problem in patients with brain tumors.
Neuropsychologist – A psychologist who specializes in managing cognitive problems in patients with brain tumors, and is an expert in implementing neuropsychological testing.
Neurosurgeon – A surgeon who specializes in operations on patients with brain, spine or peripheral nerve tumors. Neurosurgeons form the surgical side of management in patients with tumors in the central nervous system.
Nitrosourea – A class of chemotherapies that are alkylating agents capable of crossing the blood-brain barrier, and help in the treatment of various cancers. Examples include Carmustine, Lomustine or Bendamustine.
Nuclear medicine – A division of medicine that includes physicians who specialize in the use of radioactive tracers to identify tumors using specialized machines like Positron Emission Tomography (PET) or other similar techniques. PET scans may help distinguish changes on mri from radiation versus tumor growth.
O
Occupational therapist (OT) – A healthcare provider with special training in helping patients learn to cope with disabilities, receive vocational training and will perform safety assessments.
Oligodendroglioma – A type of primary brain tumor that is composed of support cells called oligodendrocytes that have lost the ability to stop dividing. These are graded according to WHO criteria, usually grades II or III although these tumors may also transform into grade IV gliomas.
Ommaya reservoir – Ommaya reservoirs are synthetic domed containers that are placed subcutaneously under the scalp. They can be connected by tubing into the brain for removal of spinal fluid or injection of chemotherapy into spinal fluid.
Oncogene – A type of gene that, when activated by mutations, can make a cell unable to stop dividing, resulting in cancer.
Oncology – A division of medicine that helps in the study and treatment of various cancers, including brain tumors.
Optic nerve glioma – A type of tumor that involves nerves important for vision, and can be associated with neurofibromatosis type 1.
P
Palliative care – A type of treatment that focuses on supportive care to keep patients comfortable who have a terminal illness.
Palsy – A weakness or loss of function that results from damage to a nerve.
Papilledema – Swelling seen in the back of the eye that can result from increased pressure in the brain. This can be checked when a physician uses an instrument, called an ophthalmoscope, to look into the back of your eyes.
Paralysis – Complete loss of function in all involved muscles.
Paraneoplastic syndromes – Rare syndromes that can be found in patients with certain kinds of cancer, such as Hodgkin's lymphoma, lung cancer, breast cancer and gynecological cancers. The syndrome results when the immune system gets activated against a tumor, but mistakenly attacks various organ systems in the body. These syndromes can be treated with steroids or other immunosuppressive medications or therapies. Treating the primary tumor, which stimulates the immune response, can help as well.
Paresthesia – Unusual sensations that can feel like burning, tingling, a sense of cool or heat, or electrical pains. These can result from neuropathy related to medical conditions like diabetes, hypothyroidism, chemotherapy or certain cancers like multiple myeloma.
Pathologist – A physician who receives tumor tissue from a neurosurgeon in the operating room, and tests the tissue to identify whether a tumor is present, or if the tissue represents a non-cancerous process.
PET (positron emission tomography) scan – This is a special kind of machine that is used to identify tumors through the usage of radiolabeled tracers. These tracers may include a molecule of glucose or amino acids like dopamine or methionine.
Petit mal seizure (aka absence seizure) – This is brief seizure that involves staring spells with a loss of consciousness, usually seen in children.
Phase I – This is a type of clinical trial that evaluates an experimental agent to determine safety and the highest dose that can be tolerated by a patient.
Phase II – This is a type of clinical trial that evaluates benefit or efficacy of an experimental agent, and is compared to historical data. These trials usually involve smaller numbers of patients compared to phase III trials.
Phase III – This trial is designed to compare an experimental therapy to an existing therapy, commonly referred to as the control arm. This study is typically much larger than a phase I or II trial, and is a more reliable measure than phase I or II data in determining benefit (efficacy).
Physical therapist – A medical provider who specializes in helping patients with neurological impairment, such as weakness or problems with balance, to develop exercise programs that strengthen muscles and help patients cope with their deficits. For example, patients who have problems with balance can learn how to walk safely after consulting with a physical therapist.
Pineal tumors – These are tumors that arise in the region of the pineal gland, which is located in the middle of the brain, just above the midbrain. Examples of such tumors include pineocytomas, pineoblastomas, pineal parenchymal tumors of intermediate differentiation or germ cell tumors.
Pituitary adenoma – A slow-growing, primary brain tumor that originates in the pituitary gland, and can result in a variety of syndromes, such as Cushing's syndrome, hyperthyroidism, galactorrhea, and acromegaly.
Pituitary gland – This is an organ in the brain that releases a variety of hormones that help maintain the internal environment of the human body. These hormones help regulate organs like the thyroid gland, adrenal gland, sex organs and also stimulate growth.
Pituitary tumors – These are slow-growing, low grade tumors that can either result in visual problems or release chemicals that can lead to other symptoms, such as excessive growth in acromegaly, breasts leaking milk inappropriately in galactorrea or a change in body appearance as seen in Cushing's syndrome. These are usually treated with medical therapy, surgery, radiosurgery or external beam irradiation.
Placebo – A substance that is not active and is used as a comparison to an experimental therapy in a clinical trial. A placebo is used in a clinical trial to help prove whether or not an experimental therapy is truly effective or not. Patients with cancer do not receive all placebo, and must have some form of active treatment included in any trial, for ethical reasons.
Platelets – Special types of cells that are produced in the bone marrow and are used to help stop bleeding. Platelet counts can drop in response to certain chemotherapies, and low platelet counts are usually managed with transfusions or close monitoring with lab draws.
Pons – The middle part of the brainstem, and it primarily controls balance, coordination and eye movements.
Posterior – The back part of an object in question.
Posterior fossa – The back part of the brain that holds the brainstem and cerebellum.
Preclinical testing – These are experimental studies conducted on lab animals or tumor cells in an effort to determine if a drug carries the potential to help treat human diseases. If successful, such treatments advance to human trials, such as phase I, II or III trials.
Primary central nervous system lymphoma – A malignant brain tumor that arises from white blood cells and can be present in the brain, spinal cord or spinal fluid. Lymphoma can originate in the central nervous system, or spread to it from a lymphoma that starts elsewhere in the body.
Primitive neuroectodermal tumor (PNET) – An uncommon tumor that is made up of abnormally dividing nerve cells, and is usually seen in children, although rare cases have been seen in adults. These are grade IV tumors according to WHO criteria. Medulloblastoma is one type of PNET.
Prognosis – The predicted outcome for a patient relative to their diagnosis.
Prophylactic – Treatments given to help prevent a particular problem or disease.
Protocol – A written plan that outlines all elements of a clinical trial. It also can describe a particular chemotherapy plan that uses one or more drugs.
Q
Quality of life – An important aspect in the treatment of tumors that emphasizes the enjoyment of life as a whole. Quality of life can be measured using surveys, and can indicate how satisfied a patient is with their daily lives and ability to perform their activities of daily living.
R
Radiation necrosis – Damage to brain tissue that results in swelling and physical problems such as headaches, weakness or seizures. The most common time, if it occurs, is 6 months to 2 years from the start of treatment but has been reported up to 13 years or longer. The majority of patients treated with radiation therapy in the brain do not have clinically significant radiation necrosis, but the risks should be discussed with your radiation oncologist before beginning treatment.
Radiation therapy/radiotherapy – A form of treatment used to fight brain tumors. Radiation is a form of energy that is generated by a specialized machine, and targets a tumor to induce damage that will hopefully kill or at least stop tumor cells from dividing. The treatment is managed by a specialized doctor called a radiation oncologist.
Radioresistant – A term commonly used to describe certain tumor types that can be resistant to radiation treatment. Examples include melanoma and sarcoma.
Radiosensitive – A term commonly used to describe certain tumor types that can be sensitive to radiation treatment. Examples include lymphoma and breast cancer.
Radiosurgery – A specialized machine that is used to treat small lesions like tumors, in or outside of the nervous system, using an intense laser beam. Examples include cyberknife, linac and gamma-knife machines. Usually the size limit for treatable tumors is 3 cm or less, but cyberknife systems can be used to treat larger tumors.
Randomized clinical trial – An experimental trial that involves taking a group of patients, placing them in two or more groups in a completely random fashion, and each group would receive a study drug or placebo, plus additional standard therapies. The purpose is to determine whether an experimental medication works for a particular problem, such as a brain tumor, or not.
Recurrence – A term used to describe when a problem comes back again, such as a new growth of a brain tumor.
Red blood cells – Cells that are produced by bone marrow that carry oxygen from lungs to the rest of the body. A low number of red blood cells is called anemia, and can result from certain treatments, such as chemotherapy, or medical conditions.
Rehabilitation – The process of using various exercise programs to help improve parts of the body that are weak or not working well, as a result of a particular medical condition, such as a brain tumor. Rehabilitation can be carried out at home, using exercise programs, at a physical therapy center, or in a dedicated rehabilitation facility.
Remission – No evidence of growing tumor, either on examination of a patient or when using specific tests, such as blood tests or special machines like xrays, CT, MRI or PET scans.
Resection – Another term used to describe surgical removal of a medical problem, such as a brain tumor.
Residual tumor – Tumor that cannot be removed surgically and is therefore still present after a surgery is done. Residual tumor can be seen by surgeon in the operating room or when using special scans like MRI.
S
Salvage treatment – A term used to describe treatments given to patients when standard therapies are no longer working. The intent is to help prolong life in patients who are still strong enough to tolerate treatment.
Sarcoma – A type of tumor that can arise from bone, cartilage, muscle or connective tissue.
Schwannoma – A type of tumor that grows from a material called myelin, which serves as insulation on all nerves to help them work better. Schwannomas grow off peripheral nerves, and can be found in many different parts of the body. Most schwannomas are slow-growing tumors, and might be treated with surgery, radiosurgery, radiation therapy, and less so chemotherapy.
Second-line treatment – A term referred to initiating treatment with a second form of therapy, once the first therapy plan is no longer working.
Seizures – A symptom of irritation in the brain that can occur suddenly, and may or may not feature a loss of consciousness. Seizures can be small, such as a temporary loss of sensation, or twitching of the face, hand or leg. Seizures may also be bigger, involving a loss of consciousness and a lot of shaking of all extremities. Tongue-biting can occur, as can drooling or losing control over urination or bowel movements (ie incontinence). If a loss of consciousness occurs with a seizure, a patient may be confused for a period of time once the seizure has stopped. Seizures can last a few seconds, or several minutes. Seizures can also occur one time or several times in a day. Seizures are usually treated with medication, although sometimes surgery can help.
Shunt – A surgically implanted tube that helps drain fluid from the brain's ventricular system to the abdominal cavity.
Social worker – A medical provider who provides expertise in a variety of areas, such as emotional support and insurance issues. A social worker can provide a variety of important resources that are helpful for quality of life and for coping with a difficult diagnosis.
Spasticity – Increased muscle tone that can result after injury to the brain or spinal cord. Symptoms include stiffness, weakness, pain and cramping.
Spinal cord – An important part of the nervous system that carries nerves from the brain that will ultimately innervate muscles and provide sensory input from all parts of the body. The spinal cord is located from the neck down to the lower back, and is housed in the bony spinal column.
Spinal fluid – See Cerebrospinal Fluid (CSF).
Spinal tap – See Lumbar Puncture (LP)
Stable disease – A way of describing whether a tumor has grown or not on a neuroimaging scan, such as an MRI or CT scan. If a tumor has not grown, then a patient is classified as having stable disease. There are specific criteria to evaluate scan results, mainly for the purposes of clinical trials, called MacDonald criteria, Recist criteria and Levin criteria.
Standard treatment – A treatment that has been shown through a variety of published reports to be proven helpful in the management of certain diseases.
Stem cells – Special kinds of cells that are present in a fetus and, to some extent, in certain parts of an adult that can grow into a different type of cell in the human body. Stem cells are a subject of interest in developing treatments for certain medical problems, such as brain tumors.
Stereotactic – Describes a way to specifically target a particular area of the body. Examples include for a biopsy or radiosurgery.
Stereotactic needle biopsy – A biopsy that is done on a specific target, and can be done by a neurosurgeon in the brain or by a radiologist in other organs of the body using a CT or ultrasound.
Stereotactic radiation – A type of radiation that is used to target specific lesions in the body. Sometimes referred to as SRS, this can be done using radiation machines or with radiosurgical devices like cyberknife, linac or gamma-knife systems.
Steroids – See Glucocorticoids
Stomatitis – Painful ulcers that can be located in the mouth or around the outside of the mouth, usually from chemotherapy.
Subcutaneous – Under the skin. Examples include an injection subcutaneously, which means directly under the skin.
Superficial – A term used to describe anything that is close to or on the surface of something.
Systemic – A term that indicates something is present throughout the body or a particular system.
T
T cells – A type of white blood cell made by the immune system, in the bone marrow, that helps attack foreign invaders in the body, such as tumors or infections. Helper T cells will make the immune response stronger, and cytotoxic T cells actively kill foreign cells or infectious agents.
Targeted therapy – A type of treatment that specifically targets a particular receptor, enzyme, or chemical. Examples include old drugs such as methotrexate that targets an enzyme, dihydrofolate reductase, and new humanized antibodies like bevacizumab that target vascular endothelial growth factor (VEGF).
Temozolomide – Also sold as Temodar, an oral chemotherapy that is FDA approved to treat WHO grade III and IV gliomas.
Tentorium – A membrane in the brain that covers the cerebellum, and separates the cerebellum from the upper most parts of the brain.
Tinnitus – A sound like buzzing or ringing in one or both ears. Potential reasons for tinnitus include acoustic neuromas or problems with the inner ear.
Toxicity – Side effects of a particular test or treatment. Toxicity is an important part of a clinical trial, to determine if an experimental medication is safe or not.
Transformation – The process by which a normal cell can become a cancerous or malignant cell. Usually a normal cell will take on mutations in its DNA that disable its ability to stop itself from dividing, leading to a tumor.
Translational research – A method used to conduct scientific research in an effort to make research in a lab applicable to the clinical management of patients.
Transsphenoidal surgery – A surgical procedure carried out by neurosurgeons, going through the upper lip or nose, to remove tumors in the pituitary region, such as pituitary adenomas or craniopharyngiomas.
Tumor – A collection of cells forming a tumor that can be benign or malignant in nature.
Tumor marker – A substance that can be secreted by a tumor and identified through a series of blood or body fluid tests to indicate either a tumor is present, has grown or returned.
Tumor progression – Growth of tumor seen on radiological scans such as MRI, CT or nuclear medicine scans like PET. This is included in measuring techniques like Recist, MacDonald or Levin criteria, and is an important measurement in clinical practice and for experimental trials.
Tumor suppressor gene – A gene that makes a protein or enzyme that helps stop a cell from dividing. These genes can take on mutations that make them stop working, and that can lead to a tumor.
U
Ultrasound – A special radiological machine that uses sound waves to create images or pictures of certain organs in the human body.
V
Vascular – A term referring to blood vessels.
Vascularity – A term referring to how many blood vessels are feeding a particular organ or tumor.
VEGF (vascular endothelial growth factor) – A protein that is released by the human body or a tumor that results in the creation of new blood vessels. VEGF is a target for drugs like bevacizumab (avastin) in the treatment for tumors like high-grade gliomas.
Ventricles – Fluid-filled sacs in the brain that contain spinal fluid.
Vertigo – A form of dizziness, such as a room spinning around, that can result from a variety of medical conditions, such as inner ear problems or tumors like acoustic neuromas.
W
White blood cells – Cells that are made in the bone marrow and help to fight infection or anything interpreted as foreign in the human body.
White matter – An area in the brain that contains parts of neurons that carry signals from the brain to the rest of the body (ie axons).
WHO (World Health Organization) – The global authority for health in the United Nations system. The WHO criteria for grading tumors is commonly used in neuro-oncology.
