Thyroid Nodules Glossary of Terms

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Adenoma: A benign tumor that arises in or resembles glandular tissue. If it becomes cancerous, it is called an adenocarcinoma.

Anesthesia: Loss of feeling or awareness. A general anesthetic puts the person to sleep. A local anesthetic causes loss of feeling in a part of the body such as a tooth or an area of skin without affecting consciousness. Regional anesthesia numbs a larger part of the body such as a leg or arm, also without affecting consciousness. The term "conduction anesthesia" encompasses both local and regional anesthetic techniques. Many surgical procedures can be done with conduction anesthesia without significant pain. In many situations, such as a C-section, conduction anesthesia is safer and therefore preferable to general anesthesia. However, there are also many types of surgery in which general anesthesia is clearly appropriate.

Antibody: An immunoglobulin, a specialized immune protein, produced because of the introduction of an antigen into the body, and which possesses the remarkable ability to combine with the very antigen that triggered its production.
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Aspiration: Removal of a sample of fluid and cells through a needle. Aspiration also refers to the accidental sucking in of food particles or fluids into the lungs.

Autoimmune: Pertaining to autoimmunity, a misdirected immune response that occurs when the immune system goes awry and attacks the body itself.
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Autopsy: A postmortem examination. Also called a necropsy.
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Benign: Not cancer. Not malignant. A benign tumor does not invade surrounding tissue or spread to other parts of the body. A benign tumor may grow but it stays put (in the same place).
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Biopsy: The removal of a sample of tissue for purposes of diagnosis. (Many definitions of "biopsy" stipulate that the sample of tissue is removed for examination under a microscope. This may or may not be the case. The diagnosis may be achieved by other means such as by analysis of chromosomes or genes.)
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Calcitonin: A hormone produced by the thyroid gland that lowers the levels of calcium and phosphate in the blood and promotes the formation of bone.
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Calcium: A mineral found mainly in the hard part of bones, where it is stored. Calcium is added to bones by cells called osteoblasts and is removed from bones by cells called osteoclasts. Calcium is essential for healthy bones. It is also important for muscle contraction, heart action, nervous system maintenance, and normal blood clotting. Food sources of calcium include dairy foods, some leafy green vegetables such as broccoli and collards, canned salmon, clams, oysters, calcium-fortified foods, and tofu. According to the National Academy of Sciences, adequate intake of calcium is 1,200 milligrams a day (four glasses of milk) for men and women 51 and older, 1,000 milligrams a day for adults 19 through 50, and 1,300 milligrams a day for children 9 through 18. The upper limit for calcium intake is 2.5 grams daily.

Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).
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Capsule: Capsule has many meanings in medicine including the following:

1. In medicine, a membranous structure that envelops an organ, a joint, tumor, or any other part of the body. It is usually made up of dense collagen-containing connective tissue.
2. In pharmacy, a solid dosage form in which the drug is enclosed in a hard or soft soluble container, usually of a form of gelatin.
3. In microbiology, a coat around a microbe, such as a bacterium or fungus.

Carcinoma: Cancer that begins in the skin or in tissues that line or cover body organs. For example, carcinoma can arise in the breast, colon, liver, lung, prostate, and stomach.

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.
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Clinical trials: Trials to evaluate the effectiveness and safety of medications or medical devices by monitoring their effects on large groups of people.
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Computed tomography: An x-ray procedure that uses the help of a computer to produce a detailed picture of a cross section of the body. Also called a CT scan or CAT scan.

CT scan: Computerized tomography scan. Pictures of structures within the body created by a computer that takes the data from multiple X-ray images and turns them into pictures on a screen. CT stands for computerized tomography.
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Cyst: A cyst is an abnormal, closed sac-like structure within a tissue that contains a liquid, gaseous, or semisolid substance. A cyst can occur anywhere in the body and can vary in size. The outer, or capsular, portion of a cyst is termed the cyst wall.

Diagnosis: 1 The nature of a disease; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies. 3 The identification of any problem. The diagnosis was a plugged IV.
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Endocrinology: The study of hormones, their receptors, the intracellular signalling pathways they invoke, and the diseases and conditions associated with them.
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Esophagus: The tube that connects the pharynx (throat) with the stomach. The esophagus lies between the trachea (windpipe) and the spine. It passes down the neck, pierces the diaphragm just to the left of the midline, and joins the cardiac (upper) end of the stomach. In an adult, the esophagus is about 25 centimeters (10 inches) long. When a person swallows, the muscular walls of the esophagus contract to push food down into the stomach. Glands in the lining of the esophagus produce mucus, which keeps the passageway moist and facilitates swallowing. Also known as the gullet or swallowing tube. From the Greek oisophagos, from oisein meaning to bear or carry + phagein, to eat.

Family history: The family structure and relationships within the family, including information about diseases in family members.
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Fetus: The unborn offspring from the end of the 8^th week after conception (when the major structures have formed) until birth. Up until the eighth week, the developing offspring is called an embryo.

Fine needle aspiration: The use of a thin needle to withdraw material from the body. For example, this method is commonly used to determine whether a nodule in the thyroid gland is benign or malignant (fine needle aspiration biopsy of the thyroid). A fine gauge needle is placed into the nodule and a drop of blood is withdrawn. The cells are studied under the microscope by an pathologist.

Gland: 1. A group of cells that secrete a substance for use in the body. For example, the thyroid gland. 2. A group of cells that removes materials from the circulation. For example, a lymph gland.

Goiter: Enlargement of the thyroid gland.
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Hashimoto thyroiditis: A progressive disease of the thyroid gland characterized by the presence of antibodies directed against the thyroid, and by infiltration of the thyroid gland by lymphocytes. Hashimoto thyroiditis is the most common cause of hypothyroidism in North America and Europe. In this condition, the thyroid gland is usually enlarged (goiter) and has a decreased ability to make thyroid hormones. Hashimoto disease predominantly affects women, and can be inherited. It is also known as autoimmune thyroiditis and Hashimoto disease.

Hoarseness: Hoarseness is a term referring to abnormal voice changes. Hoarseness may be manifested as a voice that sounds breathy, strained, rough, raspy, or a voice that has higher or lower pitch. There are many causes of hoarseness, including viral laryngitis, vocal cord nodules, laryngeal papillomas, gastroesophageal reflux-related laryngitis, and environmental irritants (such as tobacco smoking). An accumulation of fluid in the vocal cords associated with hoarseness has been termed Reinke's edema. Reinke's edema may occur as a result of cigarette smoking or voice abuse (prolonged or extended talking or shouting). Rarely, hoarseness results from serious conditions such as cancers of the head and neck region.

Hormone: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs.
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Hormone therapy: A form of treatment that takes advantage of the fact that certain cancers depend on hormones to grow. Hormone therapy may include giving hormones to the patient or decreasing the level of hormones in the body.

Hyperplasia: A condition in which there is an increase in the number of normal cells in a tissue or organ.

Hypothyroid: Deficiency of thyroid hormone which is normally made by the thyroid gland which is located in the front of the neck:

Indicate: In medicine, to make a treatment or procedure advisable because of a particular condition or circumstance. For example, certain medications are indicated for the treatment of hypertension during pregnancy while others are contraindicated.

Inflammation: A basic way in which the body reacts to infection, irritation or other injury, the key feature being redness, warmth, swelling and pain. Inflammation is now recognized as a type of nonspecific immune response.
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Intervention: The act of intervening, interfering or interceding with the intent of modifying the outcome. In medicine, an intervention is usually undertaken to help treat or cure a condition. For example, early intervention may help children with autism to speak. "Acupuncture as a therapeutic intervention is widely practiced in the United States," according to the National Institutes of Health. From the Latin intervenire, to come between.

Iodine: An essential element in the diet used by the thyroid gland to make thyroid hormones.
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Kidney: One of a pair of organs located in the right and left side of the abdomen which clear "poisons" from the blood, regulate acid concentration and maintain water balance in the body by excreting urine. The kidneys are part of the urinary tract. The urine then passes through connecting tubes called "ureters" into the bladder. The bladder stores the urine until it is released during urination.

Lubricant: An oily or slippery substance. A vaginal lubricant may be helpful for women who feel pain during intercourse because of vaginal dryness.

Lymph: An almost colorless fluid that travels through vessels called lymphatics in the lymphatic system and carries cells that help fight infection and disease.

Lymphoma: Tumor of the lymphoid tissue. Diagnosis is by biopsy. Treatment may be chemotherapy, radiation, surgery, or medication, depending on the age of the patient and type of tumor.

Magnetic resonance imaging: A special radiology technique designed to image internal structures of the body using magnetism, radio waves, and a computer to produce the images of body structures. In magnetic resonance imaging (MRI), the scanner is a tube surrounded by a giant circular magnet. The patient is placed on a moveable bed that is inserted into the magnet. The magnet creates a strong magnetic field that aligns the protons of hydrogen atoms, which are then exposed to a beam of radio waves. This spins the various protons of the body, and they produce a faint signal that is detected by the receiver portion of the MRI scanner. A computer processes the receiver information, and an image is produced. The image and resolution is quite detailed and can detect tiny changes of structures within the body, particularly in the soft tissue, brain and spinal cord, abdomen and joints.
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Malignancy: A tumor that is malignant, that is cancerous, that can invade and destroy nearby tissue, and that may spread (metastasize) to other parts of the body.

Malignant: 1. Tending to be severe and become progressively worse, as in malignant hypertension. 2. In regard to a tumor, having the properties of a malignancy that can invade and destroy nearby tissue and that may spread (metastasize) to other parts of the body.
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Medical history: 1. In clinical medicine, the patient's past and present which may contain clues bearing on their health past, present, and future. The medical history, being an account of all medical events and problems a person has experienced, including psychiatric illness, is especially helpful when a differential diagnosis is needed.
2. The history of medicine.

Metabolism: The whole range of biochemical processes that occur within an organism. Metabolism consists both of anabolism and catabolism (the buildup and breakdown of substances, respectively). The biochemical reactions are known as metabolic pathways and involve enzymes that transform one substance into another substance, either breaking down a substance or building a new chemical substance. The term is commonly used to refer specifically to the breakdown of food and its transformation into energy.

Microscope: An optical instrument that augments the power of the eye to see small objects. The name microscope was coined by Johannes Faber (1574-1629) who in 1628 borrowed from the Greek to combined micro-, small with skopein, to view. Although the first microscopes were simple microscopes, most (if not all) optical microscopes today are compound microscopes.

Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.

MRI: Abbreviation and nickname for magnetic resonance imaging. For more information, see: Magnetic Resonance Imaging; Paul C. Lauterbur; Peter Mansfield.

Neck: The part of the body joining the head to the shoulders. Also, any narrow or constricted part of a bone or organ that joins its parts as, for example, the neck of the femur bone.

Neoplasm: A tumor. An abnormal growth of tissue. The word neoplasm is not synonymous with cancer. A neoplasm may be benign or malignant.
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Nodule: A small solid collection of tissue, a nodule is palpable (can be felt). It may range in size from greater than 1.0 cm (3/8 inch) to somewhat less than 2 cm (13/16 inch) in diameter. A nodule may be present in the epidermis, dermis or subcutis (at any level in the skin).
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Nuclear medicine: The branch of medicine concerned with the use of radioisotopes in the diagnosis, management, and treatment of disease. Nuclear medicine uses small amounts of radioactive materials or radiopharmaceuticals, substances that are attracted to specific organs, bones, or tissues. The radiopharmaceuticals used in nuclear medicine emit gamma rays that can be detected externally by special types of cameras: gamma or PET cameras. These cameras work in conjunction with computers used to form images that provide data and information about the area of body being imaged. The amount of radiation from a nuclear medicine procedure is comparable to that received during a diagnostic x-ray.

Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia. Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.
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Pathologist: A doctor who identifies diseases by studying cells and tissues under a microscope.

Pediatrics: "Pediatrics is concerned with the health of infants, children and adolescents, their growth and development, and their opportunity to achieve full potential as adults." (Richard E.Behrman in Nelson's Textbook of Pediatrics)
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Prenatal: Occurring or existing before birth.
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Probe: (1) In surgery, a probe is a slender flexible rod with a blunt end used to explore, for example, an opening to see where it goes. (2) In molecular genetics, a probe is a labeled bit of DNA or RNA used to find its complementary sequence or locate a particular clone like homing in on a needle in a haystack.

Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.
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Radioactive: Emitting energy waves due to decaying atomic nuclei. Radioactive substances are used in medicine as tracers for diagnosis, and in treatment to kill cancerous cells.

Radioactive iodine: An isotope of the chemical element iodine that is radioactive. Radioactive iodine is used in diagnostic tests as well as in radiotherapy of an hyperactive thyroid gland (hyperthyroidism), most often due to Graves' disease.
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Radioisotope: A version of a chemical element that has an unstable nucleus and emits radiation during its decay to a stable form. Radioisotopes have important uses in medical diagnosis, treatment, and research. A radioisotope is so-named because it is a radioactive isotope, an isotope being an alternate version of a chemical element that has a different atomic mass.

Radiologist: A physician specialized in radiology, the branch of medicine that uses ionizing and nonionizing radiation for the diagnosis and treatment of disease.
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Radionuclide: An unstable form of a chemical element that radioactively decays, resulting in the emission of nuclear radiation. Also called a radioisotope.

Radionuclide scan: An examination that produces pictures of internal parts of the body. The patient is given an injection or swallows a small amount of radioactive material (a radionuclide). A scanner machine then measures the radioactivity in certain organs. Also called an isotope scan.

Scan: As a noun, the data or image obtained from the examination of organs or regions of the body by gathering information with a sensing device.
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Stomach: 1. The sac-shaped digestive organ that is located in the upper abdomen, under the ribs. The upper part of the stomach connects to the esophagus, and the lower part leads into the small intestine.
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Substance: 1. Material with particular features, as a pressor substance.
2. The material that makes up an organ or structure. Also known in medicine as the substantia.
3. A psychoactive drug as, for example, in substance abuse.

Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office.
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Therapy: The treatment of disease.
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Throat: The throat is the anterior (front) portion of the neck beginning at the back of the mouth, consisting anatomically of the pharynx and larynx. The throat contains the trachea and a portion of the esophagus.

Thyroid: 1. The thyroid gland. Also, pertaining to the thyroid gland. 2. A preparation of the thyroid gland used to treat hypothyroidism. 3. Shaped like a shield. (The thyroid gland was so-named by Thomas Wharton in 1656 because it was shaped like an ancient Greek shield.)
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Thyroid cancer: Cancer of the gland in front of the neck that normally produces thyroid hormone which is important to the normal regulation of the metabolism of the body. There are 4 major types of thyroid cancer -- papillary, follicular, medullary, and anaplastic. The most common symptom of thyroid cancer is a lump, or nodule, that can be felt in the neck. The only certain way to tell whether a thyroid lump is cancer is by examining the thyroid tissue, obtained using a needle or surgery to obtain a biopsy.

Thyroid gland: A gland that makes and stores hormones that help regulate the heart rate, blood pressure, body temperature, and the rate at which food is converted into energy. Thyroid hormones are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism) in the body. Thyroid hormones also help children grow and develop.
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Thyroid hormone: A chemical substance made by the thyroid gland for export into the bloodstream. The thyroid gland needs iodine to make thyroid hormones. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3).
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Thyroid hormones: Chemical substances made by the thyroid gland, which is located in the front of the neck. This gland uses iodine to make thyroid hormones, which are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism), and are involved in the circadian rhythms that govern sleep, among other essential functions.
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Thyroid scan: An image taken of the thyroid gland after radioactive iodine is taken by mouth. The thyroid gland is in front of the neck:

Thyroid stimulating hormone: A hormone produced by the pituitary gland at the base of the brain in response to signals from the hypothalamus gland in the brain. Thyroid stimulating hormone (TSH) promotes the growth of the thyroid gland in the neck and stimulates it to produce more thyroid hormones. When there is an excessive amount of thyroid hormones, the pituitary gland stops producing TSH, reducing thyroid hormone production. This mechanism maintains a relatively constant level of thyroid hormones circulating in the blood.
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Thyroidectomy: The surgical removal of part or all of the thyroid gland.

Thyroiditis: Inflammation of the thyroid gland which is located in front of the neck:

Tomography: The process for generating a tomogram, a two-dimensional image of a slice or section through a three-dimensional object. Tomography achieves this remarkable result by simply moving an x-ray source in one direction as the x-ray film is moved in the opposite direction during the exposure to sharpen structures in the focal plane, while structures in other planes appear blurred. The tomogram is the picture; the tomograph is the apparatus; and tomography is the process.
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TSH: Stands for thyroid stimulating hormone, a hormone produced by the pituitary gland at the base of the brain in response to signals from the hypothalamus gland in the brain. TSH promotes the growth of the thyroid gland in the neck and stimulates it to produce more thyroid hormones. When there is an excessive amount of thyroid hormones, the pituitary gland stops producing TSH, reducing thyroid hormone production. This mechanism maintains a relatively constant level of thyroid hormones circulating in the blood.
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Tumor: An abnormal mass of tissue. Tumors are a classic sign of inflammation, and can be benign or malignant (cancerous). There are dozens of different types of tumors. Their names usually reflect the kind of tissue they arise in, and may also tell you something about their shape or how they grow. For example, a medulloblastoma is a tumor that arises from embryonic cells (a blastoma) in the inner part of the brain (the medulla). Diagnosis depends on the type and location of the tumor. Tumor marker tests and imaging may be used; some tumors can be seen (for example, tumors on the exterior of the skin) or felt (palpated with the hands).
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Ultrasound: High-frequency sound waves. Ultrasound waves can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques. Ultrasound is often used to examine a fetus during pregnancy. There is no convincing evidence for any danger from ultrasound during pregnancy.