Directory of Relevant Medical Terms

Antithyroid antibodies
Any antibody that attacks or improperly binds to an individual’s thyroid gland. These antibodies are made by the patient’s own immune system and are often found in patients with autoimmune disorders.
Antiperoxidase (antimicrosomal) antibody
A specific antithyroid antibody. These antibodies are often found in patients with Hashimoto’s thyroiditis (an autoimmune thyroid disease)
Antithyroid drugs
Medications that slow or stop the thyroid gland’s ability to produce thyroid hormone. These are often used in patients that have an overactive thyroid gland.
Armour Thyroid
The brand name for a natural thyroid hormone replacement drug derived from pig thyroid glands.
Autoimmune
A condition in which an individual’s immune system mistakenly attacks or improperly affects their own tissues or organs.
AJCC system
American Joint Committee on Cancer staging system. A standardized system for classifying the severity of cancer based on different prognostic factors. Patients are often given the stage of their thyroid cancer following surgery based on both pathologic factors and imaging findings.
Basal body temperature
The lowest body temperature attained by the body at rest. This temperature is usually measured immediately after waking.
Bladderwrack
A specific type of seaweed occasionally found in nutritional supplements that contains high levels of iodine.
Bone scan
A nuclear imaging test that helps diagnose and track several types of bone disease. A bone scan is also an important tool for detecting cancer that has spread (metastasized) to the bone from a tumor that started in a different organ, such as the thyroid. It can also help diagnose small fractures and infections.
Biopsy
A procedure involving the removal of suspicious cells or tissues for examination. The tissue may be examined under a microscope by a pathologist, or analyzed chemically and genetically. A fine needle aspiration is a biopsy of thyroid cells that can be performed on suspicious thyroid nodules or lymph nodes.
Benign tumor
A tumor that lacks the ability to spread to other parts of the body. These tumors are not cancer. However, benign tumors such as thyroid adenomas can be a health problem if they produce too much thyroid hormone and may need to be treated either with medication or surgery.
Cold nodule
A firm round mass located in the thyroid that does not concentrate radioactive isotopes during a thyroid scan. These nodules produce less than normal amounts of thyroid hormone and are considered suspicious for thyroid cancer. A physician may elect to do a biopsy to rule out the chance of cancer.
Cytomel
The brand name drug of liothyronine sodium (synthetic T3). It is used for thyroid replacement therapy.
Cowden Syndrome
A rare genetic disorder characterized by multiple noncancerous, tumor-like growths found all over the body, called hamartomas. These patients are also at an increased risk of developing certain cancers, including thyroid cancer.
Carney Complex
A disorder characterized by an increased risk of acquiring several types of tumors. Affected individuals usually have changes in skin coloring (hyperpigmentation).
Congenital hypertrophy of retinal pigment epithelium (CHRPE)
A unique congenital anomaly of the retina that has the appearance of a freckle in the back of the eye. It is found more commonly in patients with Gardner’s syndrome, a condition which predisposes patients to multiple cancers, including thyroid carcinoma.
Chyle fistula
A leakage of lymphatic fluid from the lymphatic vessels. This is a potential complication of any surgery involving the lower part of the neck, which may damage the thoracic or accessory thoracic ducts (large lymphatic vessels). This complication may occur following lymph node removal during thyroid cancer treatment.
CT scans
An abbreviation for computerized tomography scan. These scans use ionizing radiation (a series of X-rays) to produce cross-sectional images of the bones and soft tissues inside the body. It is often used prior to an operation to help the surgeon see the extent of the cancer that is present. It can also be used to scan other parts of the body for the presence of cancer.
Chvostek sign
One of the first signs seen in patients with low levels of calcium in their blood (hypocalcemia). When the facial nerve is tapped at the angle of the jaw, the facial muscles on the same side of the face will contract momentarily. This indicates that the patient’s calcium levels need to be checked with the possibility of requiring supplemental calcium.
Dysphagia
The medical term used to describe difficulty swallowing.
Dyspnea
The medical term used to describe difficulty breathing.
Dosimetry
The amount of radiation absorbed in an individual’s tissue. For patient’s receiving radiation therapy the amount or radiation exposure is carefully monitored to ensure safety. The amount of radiation is counted in Sv (Sieverts) or Gy (Grey). These are calculated each time a patient is exposed to radiation.
Desmoid tumor
A slow growing tumor without any ability to metastasize. However, they can invade nearby tissues and organs causing problems. These tumors sometimes occur in people who have certain genetic disorders such as Gardner’s syndrome or familial adenomatous polyposis, which may predispose them to thyroid and other cancers.
Endocrine glands
Multiple glands throughout the body that secrete different hormonal and metabolic substances into the blood. The thyroid is an endocrine gland.
Endocrinologist
A medical doctor who specializes in treating patients with endocrine problems, including those with thyroid disease.
Euthyroid
The state of having normal thyroid function. This is determined by measuring thyroid stimulating hormone (TSH) or thyroid hormone levels in the blood.
Exophthalmos
An abnormal bulging of the eyes from their sockets. This can be a clinical sign for hyperthyroidism or Graves’ disease.
Follicular thyroid cancer
The second most common form of thyroid cancer, accounting for around 15% of all thyroid carcinomas. It more commonly occurs in women over 50 years old. Unlike papillary cancer, it is more likely to spread through the blood to distant parts of the body.
Goiter
An enlargement of the thyroid. Within the United States there are several different potential causes including hypothyroidism, hyperthyroidism, iodine deficiency, or thyroid cancer.
Goitrogen
Any substance or drug that may cause suppression of the thyroid gland by preventing iodine uptake. This can lead to thyroid enlargement and the formation of a goiter. Some examples of goitrogens are soy, millet, amioderone, and lithium.
Graves’ disease
An autoimmune disease that causes hyperthyroidism. Patient’s with this condition produce antithyroid antibodies which bind to the thyroid and cause an increase in the release of thyroid hormone. This disease is the most common cause of hyperthyroidism.
Graves’ ophthalmopathy
An inflammatory autoimmune disease affecting the eyes, which is found more commonly in patients with Graves’ disease. Individuals with this condition may experience upper eyelid retraction, swelling, redness, and eye bulging.
Hashimoto’s disease/thyroiditis
An autoimmune disorder in which the immune system slowly destroys the thyroid gland. Without treatment this ultimately leads to hypothyroidism, with intermittent bouts of hyperthyroidism.
Hormones
A chemical secreted by a cell or gland that affects cells and organs elsewhere in the body. Hormones often have different effects on several different tissues. An example is the thyroid hormone, which is released into the bloodstream by the thyroid gland.
Hot nodule
A firm round mass located in the thyroid that concentrates excessive amounts of radioactive isotopes during a thyroid scan. These nodules produce more than normal amounts of thyroid hormone. They are considered much less suspicious for thyroid cancer compared to cold nodules. A physician may still elect to do a biopsy to rule out the chance of cancer.
Hyperthyroidism
Excessive production of thyroid hormone. This may be caused by an abnormal thyroid gland, autoimmune disorder, or excessive thyroid hormone replacement. Some of the main clinical signs associated with this condition are: weight loss, increased appetite, anxiety, intolerance to heat, hair loss, muscle aches, weakness, fatigue, hyperactivity, irritability, tremor, and sweating.
Hypothyroidism
Insufficient production of thyroid hormone. This may be caused by an abnormal thyroid gland, absence of all or part of the thyroid gland, autoimmune disease, or insufficient thyroid hormone replacement. Some of the main clinical signs associated with this condition are: cold intolerance, constipation, weight gain, fatigue, muscle cramps, depression, and dry/itchy skin.
Hemoptysis
The medical term for coughing up blood.
Hamartoma
A benign noncancerous, tumor-like growth. These can appear in any patient, but are seen throughout the body in patients with Cowden syndrome.
Hematoma
A localized collection of blood outside the blood vessel, in which the blood is usually clotted or partially clotted. Hematomas are a potential complication that may occur within any operated area following surgery.
Hypocalcaemia
Refers to low levels of calcium within the blood. Patients may develop hypocalcemia following the removal of their thyroid due to damage to or removal of their parathyroid glands. This is not uncommon following the removal of the thyroid and all patients are monitored for this potential complication following their surgery. Hypocalcemia following thyroid surgery can only occur when a total thyroidectomy or a completion thyroidectomy is performed. In either of those situations, all four parathyroid glands are placed at risk. It is generally believed that one functioning parathyroid gland is sufficient to prevent hypocalcemia.
Iodine
An element found in several types of food and commonly added to salt within the United States. This element is essential for the thyroid gland to manufacture thyroid hormone. As a consequence of having too little iodine in their diet, a patient may develop a goiter and/or hypothyroidism over a very long period of time.
Iodine-131
A form of radioactive iodine used for radioactive iodine ablation therapy following surgery for some patients with thyroid cancer. It is also used therapeutically to destroy part of the thyroid in certain patients with hyperthyroidism.
Isthmus
Thyroid tissue in the middle of the thyroid connecting the right and left lobes of the thyroid gland.
Isthmusectomy
The surgical removal of the isthmus of a thyroid gland.
Kelp
A kind of seaweed containing high amounts of iodine.
Levothroid
A brand of synthetic thyroxine (levothyroxine) sold in the U.S.
Levothyroxine
The generic drug name for synthetic thyroxine. It acts as a thyroid hormone replacement.
Levoxyl
A brand of synthetic thyroxine (levothyroxine) sold in the U.S.
Liothyronine
The generic drug name for the synthetic version of triiodothyronine (T3).
Liotrix
The generic drug name for the synthetic mixture of levothyroxine and liothyronine.
Lobes
Term that refers to the two sides of the thyroid gland called the right and left lobes. Some patients may also have a pyramidal lobe, which is smaller than the other two and is located above the isthmus.
Larynx
A two inch portion of the respiratory tract beneath the chin often referred to as the voice box. It contains the vocal cords, which are used to produce speech. Advanced thyroid cancer has the potential of invading or compressing this structure.
Laryngopharynx
The lowest portion of the throat and connects to the esophagus. It is directly behind the larynx and often referred to as the hypopharynx.
Lobectomy
Surgical removal of a single thyroid lobe. This procedure is often done when cancer is suspected, but not yet confirmed. If thyroid cancer is found within this lobe, the opposite lobe is later removed either during the same operation or in the future.
Lymph node dissection
Surgical removal of lymph nodes in order to determine the presence of cancer or to get rid of known cancerous involvement. This is often performed in the neck of patients with known thyroid cancer to see if their disease has spread.
Low iodine diet
A diet that avoids foods with high iodine content. This may also involve stopping levothyroxine or starting thyrogen while maintaining levothyroxine intake. Patients are often started on a low iodine diet two weeks prior to undergoing an RAI scan or RAI treatment. The purpose of this diet is to deplete the body of its stores of iodine in order to increase the effectiveness of the scan or treatment.
Lichen amyloidosis
A condition consisting of small itchy bumps under the skin of the shins. It is associated with a few syndromes, including multiple endocrine neoplasia type 2A (MEN 2A).
Medullary thyroid cancer
The third most common form of thyroid cancer. It is the only thyroid cancer that arises from parafollicular thyroid cells. Some of these patients may also have MEN2A or MEN2B syndromes putting them at risk for other tumors.
MACIS score
Used to predict the mortality for adults with papillary thyroid carcinoma. This score is based on a patient’s age, diameter of tumor, completeness of resection, local/vascular invasion, and distant metastasis.
Methimazole
A generic drug used to treat hyperthyroidism by preventing the action of iodine on the thyroid gland. This medication may also be given prior to surgery on the thyroid.
Myxedema
A condition seen in patients with hypothyroidism or hyperthyroidism that presents with swelling of the skin, most commonly around the eyes or shins.
Malignant tumor
Also referred to as cancer, this is a broad group of various disease types involving uncontrollable cell growth and spread. These tumors may invade nearby structures or may use the lymphatic or vascular systems to spread to distant parts of the body (metastasis). Thyroid cancer is an example of a malignant tumor.
Metastasis
The process of cancer cells spreading to distant locations within the body.
Multiple Endocrine Neoplasms (MEN)
MEN are a group of genetic disorders that affect several of the body’s hormone-producing glands (the endocrine system). There are three major forms called MEN1, MEN2A, and MEN2B.
MEN1 frequently involves tumors within the parathyroid, pituitary, and pancreas.
MEN2A frequently involves pheochromocytomas, medullary thyroid carcinoma, and parathyroid hyperplasia.
MEN2B frequently involves pheochromocytomas, medullary thyroid carcinoma, and mucosal adenomas.
Magnetic resonance imaging (MRI)
A diagnostic test that uses magnets and radio wave energy to record images of structures inside the body. This test does not involve any ionizing radiation.
Natural thyroid
Natural thyroid hormone collected from the thyroid glands of animals used for thyroid replacement therapy.
Nodular goiter
An enlargement of the thyroid with a bumpy appearance.
Nodule
A firm round mass on or within the thyroid.
Nodulectomy
Surgical removal of a thyroid nodule.
Nuclear scan
Diagnostic imaging using radioactive substances to see structures and functions inside the body. These scans only expose the patient to a small amount of radiation. A thyroid scan is a specific type of nuclear scan often used for patients with thyroid problems. This scan involves either swallowing or being injected with radioactive iodine. The actual scan takes between 5-30 minutes to complete.
Papillary thyroid cancer
The most common form of thyroid cancer, accounting for approximately 80% of all thyroid cancers. It more commonly occurs in women between 30-40 years old. Its common location of spread is to local lymph nodes. It has the best prognosis of all types of thyroid cancer.
Parathyroid glands
Small endocrine glands found behind the thyroid gland. Most people have four of them, which secrete parathyroid hormone (PTH), controlling calcium levels and bone metabolism. These glands risk damage or death during any operation on the thyroid gland. This may lead to low calcium levels, which is monitored for after thyroid surgery. If the entire thyroid gland is removed the parathyroid glands may be reimplanted into the patient’s muscle, with the intent that they will work in this new location.
Post-partum thyroiditis
A specific type of thyroiditis that causes inflammation of the thyroid gland following pregnancy. This can result in either short-term hypo or hyperthyroidism. Around 20% of these patients will develop permanent hypothyroidism.
Potassium iodide
A compound found in iodized salt (table salt). High dose potassium iodine may be ingested as a pill after a nuclear accident to protect the thyroid from absorbing radioactive iodine.
Propylthiouracil (PTU)
A generic antithyroid drug used to treat hyperthyroidism by blocking the thyroid from producing thyroid hormone.
PET scan
A positron emission tomography (PET) scan is an imaging test that helps doctors see how the organs and tissues inside the body are functioning. This involves injecting a very small dose of radioactive chemicals. This test may be used to look for the metastatic spread of cancer throughout the body.
Pheochromocytoma
A rare tumor in the adrenal gland, located above the kidneys. It causes the release of excessive adrenaline hormones leading to bouts of increased heart rate, metabolism, and blood pressure. This tumor can be seen in patients with MEN2A and MEN2B, who are also at risk for developing medullary thyroid carcinoma.
Radioactive Iodine (RAI)
This includes Iodine-131 for therapeutic use in certain cancer patients or those with hyperthyroidism. It also encompasses Iodine-123 which is often used for diagnostic scanning of the thyroid gland for radioactive iodine uptake tests.
Resistance to Thyroid Hormone (RTH)
A very rare disorder where a patient’s cells do not respond to thyroid hormones. These patients will have very high thyroid hormone levels and higher than expected TSH levels. Often patients will present with symptoms of hypothyroidism.
Reverse T3
The inactive form of T3 that is formed during periods of stress on the body. It also acts as a blood marker for thyroid resistance.
Subclinical hypothyroidism
A form of hypothyroidism with elevated TSH levels, but normal thyroid hormone levels. Patients should not experience any clinical signs of hypothyroidism. This may progress to hypothyroidism or may regress to a euthyroid state depending on the underlying cause.
Suppression
High levels of thyroid hormone lead to a suppression of the thyroid gland, causing it to shrink. Thyroid cancer survivors may take high levels of thyroid hormone to suppress any remaining thyroid tissue, decreasing the likelihood of a recurrence.
Synthroid
A brand name drug for synthetic thyroxine (thyroid hormone).
Stridor
A high-pitched wheezing noise caused by a narrowing or blockage in the throat or voice box (larynx). There are several potential causes including compression of the larynx by thyroid cancer or swelling due to intubation.
Subtotal thyroidectomy
Surgical removal of part of the thyroid gland.
T4 to T3 conversion
A process the body performs to change the thyroid hormone T4 into the more potent version, T3. The majority of T3 in the body comes from the conversion of T4.
Tapazole
The brand name version of methimazole. This drug is used to treat hyperthyroidism by preventing the action of iodine in the thyroid gland. It may be given prior to surgery on the thyroid.
Thiocyanate
A compound, which at high levels can cause thyroid dysfunction by preventing the accumulation of iodine in the thyroid gland.
Thyrogen
A synthetic form of TSH that causes an increase in iodine uptake by the thyroid gland and may be injected into certain patients with previous thyroid cancer. This drug may be injected prior to thyroid or whole body scans using radioactive iodine. It may also be used to measure levels of thyroid proteins (thyroglobulins) or in combination with radioactive iodine ablation therapy.
Thyroglobulin (TG)
A protein made by the thyroid gland that can be used as a tumor marker for thyroid disease and thyroid cancer. These levels will be followed after a patient has been treated for thyroid cancer to look for a recurrence.
Thyroid Eye Disease
An autoimmune eye condition that may cause painful, dry, itchy eyes with swelling and changes in vision. This disease most commonly presents in patients with Graves’ disease, but may occur in some people with no thyroid disease.
Thyroid gland
A butterfly-shaped gland located in the lower part of the neck. It lies in front of and around the windpipe and secretes thyroid hormones that have many effects throughout the body. It also has the potential of developing thyroid cancer.
Thyroid Stimulating Hormone (TSH)
A hormone produced by part of the brain (pituitary gland) that acts on the thyroid gland, causing the release of thyroid hormone. Measuring TSH levels in the blood is a common way to diagnose thyroid disorders.
Thyroidectomy
Surgical removal of all or part of the thyroid gland.
Total thyroidectomy
Surgical removal of all of the thyroid gland.
Thyroiditis
A group of disorders which cause inflammation of the thyroid gland. This may lead to symptoms of hypo or hyperthyroidism. An example is Graves’ disease.
Thyrolar
A brand name of Liotrix, a synthetic drug mixture of levothyroxine and liothyronine.
Thyrotropin Releasing Hormone (TRH)
A hormone released by a part of the brain (hypothalamus) that causes the release of thyroid stimulating hormone (TSH). TSH acts on the thyroid glad causing the release of thyroid hormone.
Thyroxine (T4)
T4 is one of the two thyroid hormones produced by the thyroid gland. It can either act on the body or be converted to the more potent thyroid hormone, T3.
Toxic goiter
An enlarged thyroid gland that overproduces thyroid hormone causing hyperthyroidism. It is the most common cause of hyperthyroidism. The thyroid may have one or multiple parts that are overproducing thyroid hormone. These can be treated medically or surgically.
Triiodothyronine (T3)
T3 and T4 are the two forms of thyroid hormones. T3 can either be converted from T4 or made directly by the thyroid gland. It is more potent, but found in smaller amounts within the body than T4.
Tracheostomy
A surgically created hole through the front of the neck and into the windpipe (trachea). The surgical procedure to create this opening is called a tracheotomy. This is performed in order to place a tube through the neck to breath for the patient. This is usually done in the operating room with the patient unconscious. This opening may either be temporary, or if needed, permanent.
Tyrosine
An amino acid (chemical) that is used with iodine by the thyroid gland to make thyroid hormone. Tyrosine may be added to the diet of a hypothyroid patient and high doses should be avoided in patients with hyperthyroidism.
Trousseau sign
A medical sign used to screen for patients with low calcium in their blood. It is tested for by inflating a blood pressure cuff for three minutes.