Medical terms A–Z

An area of abnormal tissue.

In everyday speech it means tired; in a clinical note it means the level of consciousness itself has dropped, which is a different claim.

The same molecule rescues healthy tissue from one chemotherapy drug and sharpens the action of another, depending on which it is paired with.

A blood donation run in reverse: the machine keeps the white cells and hands back everything else, over several hours.

A cancer with no lump to find, because the affected cells travel in the bloodstream instead of forming a mass.

A serious problem that may occur in leukemia.

A serious problem that may occur in leukemia.

Which type is raised matters more than the total, since neutrophils, lymphocytes and eosinophils each point somewhere different.

Which type of white cell is missing matters more than the total, since neutrophils carry most of the protection against bacteria.

Leukoplakia is a thickened white patch on a mucous membrane, most often in the mouth, that occasionally develops into cancer.

Leuprolide is a hormone-suppressing injectable used for advanced prostate cancer, early puberty, and certain gynecologic conditions, sold under names including Lupron.

An old deworming drug now met far more often as a cocaine adulterant, capable of wiping out the white cells that fight infection.

A ranking system used to describe the strength of the results measured in a clinical trial or research study.

A drug used to treat actinic keratosis (a skin condition that may become cancer).

A drug used to treat skin problems caused by cutaneous T-cell lymphoma that have not gotten better after other treatment.

LH is a pituitary hormone that triggers ovulation in females and stimulates testosterone production in males, acting on the ovaries or testes respectively.

A hormone that stimulates the production of sex hormones in men and women.

A drug that inhibits the secretion of sex hormones.

Lhermitte's sign is an electric shock like sensation down the spine triggered by bending the neck forward, pointing to spinal cord irritation.

A rare, inherited predisposition to multiple cancers, caused by an alteration in the p53 tumor suppressor gene.

An anticancer drug that promotes differentiation by increasing the levels of retinoic acid within the tumor.

Sexual desire or the mental energy or emotion related to sex.

The process of tying off blood vessels so that blood cannot flow to a part of the body or to a tumor.

The instrument behind nearly every pathology slide, and one whose limit is set by the wavelength of light itself.

Different wavelengths do entirely different jobs, so the color of the light is as much a part of the prescription as the timing.

Treatment with drugs that become active and may kill cancer cells when exposed to light.

A member of a group of substances found in plants that have shown estrogenic and anticancer effects.

A procedure that may be used to deliver anticancer drugs directly to an arm or leg.

The limbic system is a group of interconnected brain structures that governs emotional response, motivation, and the formation of memories.

Cancer is found in one lung, the tissues between the lungs, and nearby lymph nodes only.

The everyday shorthand used in radiotherapy departments for the machine that produces the treatment beam.

A machine that drives electrons down a straight tube to near the speed of light and turns them into a treatment beam.

The seed of the flax plant.

A lipid is one of a broad group of water-insoluble or poorly water-soluble molecules that includes fats, phospholipids, and sterols.

A lipoma is a soft, slow-growing lump of fat cells that sits just beneath the skin and is not cancerous.

Able to dissolve, be dissolved in, or absorb lipids (fats).

Liposarcoma is a cancer arising from fat-cell precursors that most often develops in the deep soft tissue of a limb or the abdomen.

Liposomal describes a drug formulation enclosed within fat based particles, changing how the medication is absorbed, distributed, and tolerated.

A form of the anticancer drug paclitaxel that is contained in very tiny, fat-like particles.

A form of the anticancer drug irinotecan that is contained in very tiny, fat-like particles.

A liposome is a laboratory made, fat based capsule engineered to carry a drug through the body and release it more precisely.

A form of the anticancer drug paclitaxel that is contained in very tiny, fat-like particles.

A type of Pap test.

A drug that may protect healthy cells from chemotherapy and radiation without inhibiting the effects of these therapies on tumor cells.

A measure of volume for a liquid, using the metric system.

Anything shifting salt and water balance shifts lithium with it, which is why dehydration and several everyday drugs push blood levels upward.

Blood leaving the gut reaches the liver before the rest of the body, which is why it handles nutrients and toxins first.

Liver cancer includes primary tumors starting in the liver itself and, more commonly, secondary tumors that spread there from cancer elsewhere in the body.

A blood test to measure the blood levels of certain substances released by the liver.

The liver filters blood arriving straight from the gut, which is why so many cancers place their first distant deposit there.

An image of the liver created on a computer screen or on film.

A living will is a written legal document that states a person's preferences for future medical care if they can no longer communicate them.

A substance being studied in the treatment of cancer.

A substance being studied in the treatment of cancer.

A substance that contains the metal platinum and may kill cancer cells by damaging their DNA and stopping them from dividing.

A portion of an organ, such as the liver, lung, breast, thyroid, or brain.

A lobectomy removes one entire lobe of an organ, most often the lung, sparing the rest of the organ and its function.

A substance that comes from a plant known as Indian tobacco, which is different from the tobacco used to make smoking products.

A breast cancer that spreads through tissue in single file rather than forming a lump, which is why imaging so often underestimates it.

A lobule is a small subdivision of a larger lobe within an organ, forming part of the organ's internal structural and functional units.

A temporary loss of feeling in one small area of the body caused by special drugs or other substances called anesthetics.

An invasive malignant cancer confined entirely to the organ where the cancer began.

Treatment that affects cells in the tumor and the area close to it.

Localization is the process of pinpointing where a lesion, symptom, or disease originates within the body, guiding diagnosis across many medical specialties.

Localized describes a disease process confined to its original site, without evidence that it has spread to nearby tissue or elsewhere in the body.

Cancer found only in the tissues that make up the wall of the gallbladder.

Cancer is found in the lining of the chest wall and may also be found in the lining of the lung, the lining of the diaphragm (the thin muscle below the lungs and heart that separates the chest from…

Cancer that has spread from where it started to nearby tissue or lymph nodes.

Cancer that has recurred (come back) at or near the same place as the original (primary) tumor, usually after a period of time during which the cancer could not be detected.

An address rather than a resident: the locus says where on the chromosome to look, and the allele says what is found there.

A drug used to treat high levels of cholesterol and triglycerides in the blood.

A technique that uses electric current passed through a thin wire loop to remove abnormal tissue.

A combination of the drugs ritonavir and lopinavir.

Blocking the receptor rather than the enzyme is what spares this drug the persistent dry cough that its older cousins provoke.

Blocking the receptor rather than the enzyme that builds the hormone is what spares this drug class the dry cough of its predecessor.

An anticancer drug that belongs to the family of drugs called antipyrazoles.

A term used to describe cells that look nearly normal under a microscope.

A type of lymphoma that tends to grow and spread slowly, and has few symptoms.

X-rays of the colon and rectum that are taken after a person is given a barium enema.

The lower limb is a limb of the body.

A condition in which the cells of the uterine cervix are slightly abnormal.

An anticancer drug that kills cancer cells by affecting DNA synthesis.

An anticancer drug that reduces the risk of tumor cell growth and reproduction.

A lubricant reduces friction between surfaces, and in medical use it eases insertion or movement of instruments, catheters, or tissue against tissue.

A procedure in which a thin needle called a spinal needle is put into the lower part of the spinal column to collect cerebrospinal fluid or to give drugs.

Narrowing costs more flow than it appears to, because flow through a tube falls with the fourth power of the radius.

An eye drop that lowers pressure inside the eye by opening a secondary drainage route, with visible effects on lashes and iris.

A lumpectomy removes a breast tumor along with a margin of surrounding normal tissue while preserving as much of the breast as possible.

Breathing is muscle work done by the diaphragm and the rib muscles, since the lungs hold no muscle capable of moving air themselves.

The step that converts a shadow on a scan into a name, and the point at which treatment can finally be planned.

Tobacco smoke drives most cases, yet the disease also arises in people who never smoked, usually as adenocarcinoma.

A test used to measure how well the lungs work.

Cancer that has traveled to the lung from somewhere else, keeping the identity of the organ it started in.

A chronic, inflammatory, connective tissue disease that can affect the joints and many organs, including the skin, heart, lungs, kidneys, and nervous system.

A drug that inhibits the secretion of sex hormones.

A substance that is being studied in the treatment of cancer using photodynamic therapy.

A hormone made in the pituitary gland.

Luvox is the brand name for fluvoxamine, an SSRI antidepressant primarily prescribed to treat obsessive-compulsive disorder.

A drug used alone or with another drug to treat certain types of non-small cell lung cancer and malignant pleural mesothelioma.

A substance that is being studied as a treatment for cancer.