Medical terms A–Z

A slowly progressing disease in which too many white blood cells (not lymphocytes) are made in the bone marrow.

A progressive, chronic disease in which the bone marrow is replaced by fibrous tissue and blood is made in organs such as the liver and the spleen, instead of in the bone marrow.

Slow growing blood cancers whose cells mature far enough to function, which is why they are so often found by accident.

This slow-progressing blood cancer results from an acquired genetic change that causes the bone marrow to overproduce white blood cells.

A slowly progressing type of myelodysplastic/myeloproliferative disease in which too many myelomonocytes (a type of white blood cell) are in the bone marrow, crowding out other normal blood cells…

A disease in which too many neutrophils (a type of white blood cell) are found in the blood.

The problem is emptying rather than filling: air enters well enough but cannot get back out of a lung that has lost its recoil.

Pain that can range from mild to severe, and persists or progresses over a long period of time.

Refers to the early stages of chronic myelogenous leukemia or chronic lymphocytic leukemia.

A procedure that uses gold salts (a salt form of the metal element gold) to treat diseases, such as rheumatoid arthritis.

A drug that is being studied in the treatment of solid tumors.

A milky-white fluid that forms in the small intestine during digestion.

A substance being studied in the treatment of some types of cancer.

A substance being studied in the treatment of some types of cancer.

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

A substance being studied in the treatment of non-small cell lung cancer.

A part of the middle layer of the wall of the eye.

A condition in which slightly abnormal cells grow on the thin layer of tissue that covers the cervix.

A condition in which moderately abnormal cells grow on the thin layer of tissue that covers the cervix.

A condition in which abnormal cells grow on the thin layer of tissue that covers the cervix (the lower, narrow end of the uterus).

Abnormal cells are found in the cervical epithelium (the innermost lining of the cervix).

A closed loop that delivers oxygen and fuel to every cell and carries away what those cells no longer need.

The heart and its network of vessels, a closed loop delivering oxygen and fuel to tissue and carrying waste away.

Surgery to remove part or all of the foreskin (loose skin that covers the head of the penis).

A type of chronic, progressive liver disease in which liver cells are replaced by scar tissue.

One of the older SSRIs, distinguished within the class less by how well it works than by its effect on the heart's electrical timing.

A drug used to lessen the toxic effects of substances that block the action of folic acid, especially the anticancer drug methotrexate.

Melanoma that is found only in the epidermis (outer layer of skin).

Melanoma that has spread from the epidermis (outer layer of skin) down into the papillary dermis (the thin top layer of the dermis).

Melanoma that has spread down through the papillary dermis (the thin top layer of the dermis) but not into the reticular dermis (the thick bottom layer of the dermis).

Melanoma that has spread down into the reticular dermis (the thick bottom layer of the dermis).

Melanoma that has spread down into the subcutaneous tissue (tissue beneath the skin).

A system for describing how deep melanoma has spread into the skin.

The most common type of Hodgkin lymphoma, which is a cancer of the immune system.

The only bony strut between the arm and the trunk, lying under thin skin where it can be seen and felt along its whole length.

A type of cell that looks clear inside when viewed under a microscope.

A rare type of tumor, usually of the female genital tract, in which the insides of the cells look clear when viewed under a microscope.

A description of what the cells look like on a slide, applied to tumors that arise in several unrelated organs.

A soft tissue tumor that begins in a tendon (tough, fibrous, cord-like tissue that connects muscle to bone or to another structure).

A rare type of kidney cancer, in which the inside of the cells look clear when viewed under a microscope.

A shape rather than an event: the cell was never cut, and the folded outline is simply what a pathologist reports seeing.

Ordained religious leaders, and in hospitals a formal part of the care team rather than visitors from outside it.

The word draws one line above all others: between what is observed in a real patient and what is produced away from the bedside.

A physical exam of the breast performed by a health care provider to check for lumps or other changes.

Recommendations assembled from the evidence by a panel, written to inform a decision rather than to dictate what happens to any one person.

A clinical researcher studies health and disease using patient data or direct patient contact to help develop and evaluate new treatments.

The failure of a cancer to shrink after treatment.

A case series in which the patients receive treatment in a clinic or other medical facility.

The stage of cancer (extent of cancer in the body) that is based on tests that are done before surgery.

A method used to determine the stage of cancer (extent of cancer in the body).

A type of research study that tests how well new medical approaches work in people.

Assignment is the whole point, since deciding who receives what is what allows a study to demonstrate cause rather than mere association.

A clinician is a trained health professional who directly evaluates, diagnoses, or treats patients, as opposed to working solely in research or administration.

Cells that look mature and behave uselessly accumulate for years, which is why a diagnosis often arrives long before any treatment does.

An indolent (slow-growing) cancer in which immature lymphocytes (white blood cells) are found in the blood and bone marrow and/or in the lymph nodes.

A drug used in the treatment of hypercalcemia (abnormally high levels of calcium in the blood) and cancer that has spread to the bone (bone metastases).

An old blood pressure drug also used for ADHD, tics, hot flashes and opioid withdrawal, all through the same calming action on nerve traffic.

A drug that turns the sympathetic nervous system down at its source in the brain, which is why its uses reach far beyond blood pressure.

Clostridium difficile is a spore forming bacterium that causes diarrhea and colon inflammation, often following antibiotic use that disrupts normal gut bacteria.

The combination that first proved chemotherapy after surgery could stop breast cancer returning, now largely overtaken by newer schedules.

CML is a slow progressing blood cancer marked by overproduction of white blood cells, most often driven by a specific chromosomal abnormality.

A marrow disorder sitting between two families of blood disease, defined by a stubbornly high count of one white cell type.

CMV is the abbreviation for cytomegalovirus, a herpesvirus that most often causes no illness but can be serious during pregnancy or immune suppression.

A substance found in certain plants, including blessed thistle.

CNS designates the brain and spinal cord together, the central hub that processes information and coordinates the body's motor and sensory activity.

Cancer that has spread from the original (primary) tumor to the central nervous system (CNS).

A type of cancer that arises from a particular type of cell within the brain or spinal cord.

Chemotherapy or radiation therapy given to the central nervous system (CNS) as a preventive treatment.

Chemotherapy or radiation therapy given to the central nervous system (CNS) as a preventive treatment.

A tumor of the central nervous system (CNS), including brain stem glioma, craniopharyngioma, medulloblastoma, and meningioma.

A chimeric (made from human and mouse proteins) monoclonal antibody being studied in the treatment of advanced kidney cancer and other types of cancer.

Growing two cell types side by side, because a cell studied in isolation answers only half of the question.

A drug used in the treatment of infections caused by bacteria and protozoa.

A T cell that has been coated with monoclonal antibodies to enhance its ability to kill tumor cells.

The only vitamin that contains a metal, and the only one the liver can stockpile for years at a time.

A radioactive form of the metal cobalt, which is used as a source of radiation to treat cancer.

The coccyx, or tailbone, is the small triangular bone at the base of the spine formed from several fused segments.

A rare inherited disorder of DNA repair marked by failure to grow, sun sensitivity and a progressive loss of skills.

An alternative practice with a long history in fringe cancer regimens and no demonstrated effect against any disease.

Because separate brain networks handle memory, attention and language, one of them can fail while the others carry on working normally.

A type of psychotherapy that helps patients change their behavior by changing the way they think and feel about certain things.

In research, a cohort is a defined group of people sharing a characteristic or experience, followed over time to study health outcomes.

A research study that compares a particular outcome (such as lung cancer) in groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who…

A substance being studied in the treatment of cancer.

A substance being studied in the treatment of cancer.

In surgery, the cooling of a tissue, organ, or body part after its blood supply has been reduced or cut off.

In surgery, the time between the chilling of a tissue, organ, or body part after its blood supply has been reduced or cut off and the time it is warmed by having its blood supply restored.

When radioactive material is used to examine the thyroid with a scanner, nodules that collect less radioactive material than the surrounding thyroid tissue are considered "cold." A nodule that is…

A colectomy is a surgical procedure that removes all or part of the colon to treat disease or injury affecting that organ.

The word describes what the lining of the colon looks like, leaving the cause behind it to be worked out separately.

Swallowed collagen is broken down into amino acids like any other protein, so it does not arrive intact at skin or joints.

A term previously used to describe chronic diseases of the connective tissue (e.g., rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis), but now is thought to be more…

An enzyme that cuts the body's main structural protein, used as a treatment where unwanted cords of that protein need dissolving.

The only bony strut holding the arm away from the chest, and one of the most frequently broken bones at any age.

The last part of a long, twisting tube that collects urine from the nephrons (cellular structures in the kidney that filter blood and form urine) and moves it into the renal pelvis and ureters.

A surgical procedure in which the colon is attached to the anus after the rectum has been removed.

A surgical procedure in which the colon is attached to the anus after the rectum has been removed.

Contents can spend a day or more here, which is what makes the colon the place where water is reclaimed and bacteria flourish.

Few cancers offer such a long warning: the polyp stage lasts years, and removing one prevents the cancer that would have followed.

Tube-like gland found in the lining of the colon and rectum.