Medical terms A–Z

An anticancer drug formed by the combination of diphtheria toxin and a colony-stimulating factor (GM-CSF).

An inflammatory response that develops 24 to 72 hours after exposure to an antigen that the immune system recognizes as foreign.

A cell line made from human prostate cancer cells that is used in the laboratory to study the way prostate cancer cells grow.

The standard bone density scan, and one that reports mineral spread across an area rather than through a true volume.

Glands make things the body needs, and ducts are the plumbing that delivers them without spilling into surrounding tissue.

Ductal carcinoma is cancer arising from cells lining a duct, most familiar as the most common form of breast cancer.

A method used to collect cells from milk ducts in the breast.

Cancer has spread from the mucosa (innermost layer) of the colon and/or rectal wall to the submucosa (layer of tissue under the mucosa) of the colon and/or rectal wall.

Cancer has spread (1) through the muscle layer of the colon and/or rectal wall to the serosa (outermost layer) of the colon and/or rectal wall; or (2) through the serosa of the colon and/or rectal…

Cancer (1) may have spread through the mucosa (innermost layer) of the colon and/or rectal wall to the submucosa (layer of tissue under the mucosa) and may have spread to the muscle layer of the…

A staging system used to describe the extent of colorectal cancer.

One drug licensed across mood and pain, duloxetine works partly through spinal cord pathways that damp pain signals before they reach the brain.

A condition that occurs when food or liquid moves too fast into the small intestine.

Duodenitis is inflammation of the first segment of the small intestine, often sharing the same causes and symptoms as gastritis and peptic ulcer disease.

Short as it is, this stretch is where most chemical digestion happens and where several other organs empty their secretions.

A type of power of attorney.

Prostate growth depends on a hormone built from testosterone, and this drug shuts down the enzyme that performs the conversion.

The leg symptoms are not the real danger; the danger is the fragment that breaks away and lodges in the lungs.

An anticancer drug that is a type of antitumor antibiotic.

An anticancer drug that is a type of topoisomerase inhibitor.

A quick low-dose scan that turns bone strength into a single comparable number, and the measurement osteoporosis is defined by.

A two-in-one water pill, pairing a diuretic that wastes potassium with one that conserves it.

Dyscrasia refers to an abnormal condition of the blood, most often involving the cells or proteins that circulate within it.

Dysesthesia is a distorted sense of touch that makes an ordinary stimulus feel painful, unpleasant, or otherwise abnormal.

Dysfunction refers to the abnormal or impaired operation of an organ, system, or process, ranging from mild to severe depending on the cause.

A type of tumor that begins in the type of cells that give rise to egg cells and is most often found in the ovaries.

Dysgeusia is a general term for any disturbance in the sense of taste, including reduced, distorted, or absent taste perception.

Dyspepsia, or indigestion, is a group of upper-abdominal symptoms such as pain, burning, discomfort, early fullness, or uncomfortable fullness after eating.

Dysphagia is difficulty swallowing food, liquid, or saliva, ranging from mild discomfort to an inability to swallow safely.

Dysphonia is any disruption in normal voice production, most often experienced as hoarseness or an altered vocal pitch or quality.

Pathologists grade this finding from mild to severe, and the grade, not the label alone, carries most of its meaning.

A dysplastic nevus itself is benign, but its presence, particularly in larger numbers, is linked to an increased likelihood of developing melanoma.

When it comes on and in what position narrows the cause far faster than the sensation itself ever does.

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

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

Breast cancer that has not spread beyond the breast or the axillary lymph nodes.

A term used to describe cancer that is early in its growth, and may not have spread to other parts of the body.

A North American juniper, not a true cedar, whose fragrant wood yields the oil sold as cedarwood.

One of the most widespread viruses in existence, harmless in most people and yet tied to a surprising list of diseases.

The flat purple patch left when blood escapes under the skin, larger than a pinpoint spot and free of any lump.

The sweat gland that covers nearly the whole body and does the actual work of cooling it.

Ten electrodes produce twelve views of the same heartbeat, each looking at the heart from a different direction.

Echinacea is an herbal supplement derived from purple coneflower, popularly used in an effort to prevent or shorten the common cold.

The number most often quoted from the study is ejection fraction, the share of blood the left ventricle pushes out with each beat.

A study that compares large groups of people instead of individuals for differences in things such as cancer rates.

A study that compares large groups of people instead of individuals for differences in things such as cancer rates.

Speed is the usual reason it is chosen, since a response can arrive faster than medication typically achieves in severe illness.

A substance that comes from a type of sea squirt and is being studied in the treatment of cancer.

Having to do with the part of the cervix that protrudes into the vagina and is lined with epithelial cells.

A rare, fast-growing tumor of the nervous system or soft tissue that occurs in children and young adults.

A positive pregnancy test alongside an empty uterus on ultrasound is the combination that raises the question before symptoms make it obvious.

A monoclonal antibody used to prevent red blood cells from being destroyed in patients with paroxysmal nocturnal hemoglobinuria (PNH), a red blood cell disorder.

A group of conditions in which the skin becomes inflamed, forms blisters, and becomes crusty, thick, and scaly.

Built as a close chemical relative of methotrexate, it was designed to enter cells more readily and was tested in cancer without reaching approval.

Where the swelling sits, whether it pits under a finger, and whether it is one-sided are the details that separate the causes.

One of the few tests that watches the brain working moment by moment instead of photographing its structure.

A drug that may increase the effectiveness of radiation therapy.

A cell that performs a specific function in response to a stimulus; usually used to describe cells in the immune system.

Everyday speech treats it as a synonym for effectiveness; clinical research keeps them apart, and the gap between them is where treatments disappoint.

An effusion is an abnormal buildup of fluid in a body space or between tissue layers, named for the specific location involved, such as pleural or joint.

The unifying feature is molecular rather than anatomic, which is why a bone tumor and a chest wall tumor sit in the same group.

The signal telling skin and lining cells to divide, and a pathway where treatment targets the receiver rather than the signal.

Written in lower case as eGFR the same four letters mean an estimate of kidney function, an entirely unrelated measurement.

Ejaculation is a reflex process coordinated by the nervous system and involves several structures beyond the organ where semen ultimately exits the body.

Quick, painless and available almost anywhere, it is usually the first test reached for when the heart is the question.

A procedure used to do a mammogram (x-ray of the breasts) in women with breast implants.

A procedure used to do a mammogram (x-ray of the breasts) in women with breast implants.

A procedure in which pulses of weak electrical current are sent through acupuncture needles into acupuncture points in the skin.

A recording of the heart’s electrical activity from electrodes on the skin.

A treatment for severe depression and certain mental disorders.

An electrode is a conductor that carries electrical current between a device and the body, used both to deliver energy and to record biological signals.

A change in the heat and electricity passed through the skin by nerves and sweat.

The drying of tissue by a high-frequency electric current applied with a needle-shaped electrode.

A procedure in which tissue is heated to destroy abnormal cells.

The recording is often obtained under specific conditions, such as during sleep or with flashing lights, to help capture patterns not seen at rest.

A procedure to destroy tissue (such as a tumor) using an electric current.

A battery-operated device that makes a humming sound.

Where each ion sits matters more than how much exists, since the gradient across a cell membrane does the work.

The invisible region of electric and magnetic force around anything carrying current, from a power line to a phone.

Energy traveling as waves of electric and magnetic field, from radio at one end of the range to gamma rays at the other.

A stream of electrons (small negatively charged particles found in atoms) that can be used for radiation therapy.

An electron microscope uses a focused beam of electrons instead of light to produce highly magnified images of extremely small structures.

Electrophoresis separates charged molecules such as proteins or DNA using an electric current, a technique behind tests like serum protein and hemoglobin analysis.

Treatment that generates electrical pulses through an electrode placed in a tumor to enhance the ability of anticancer drugs to enter tumor cells.

The name survives from an era the procedure no longer resembles, since it is now given under anesthesia with no visible convulsion at all.

Four elements account for most of body weight, while others matter in amounts so small that a shortfall still causes recognizable disease.

A gel injection that shuts down testosterone production for months at a time, after first pushing the level higher.

In clinical trials, requirements that must be met for an individual to be included in a study.

ELISA is a laboratory test that uses enzyme-linked antibodies to detect and measure a specific substance within a fluid such as blood serum.

Eltrombopag is a medication that stimulates platelet production in the bone marrow to treat certain chronic low platelet conditions.

A substance being studied in the treatment of cancer.

An embalmer is a trained professional who chemically preserves and prepares a deceased body, most often for viewing and burial.

An embolism is a sudden blockage of a blood vessel by material that traveled there from elsewhere in the bloodstream.

The blocking of an artery by a clot or foreign material.

Weeks counted from fertilization and weeks counted from a last period differ by two, which is why embryo timelines often seem to disagree.

A mass of rapidly growing cells that begins in embryonic (fetal) tissue.

Named for the tissue it imitates rather than the tissue it came from, which is why it appears in places holding no muscle.

A mass of rapidly growing cells that begins in embryonic (fetal) tissue.

Having to do with an embryo, which is an early stage in the development of a plant or animal.

A substance that is being studied as an anticancer and antiangiogenesis drug.