| thyroid cancer | <oncology> A form of cancer that can occur in all age groups, particularly those who have had exposure to radiation. Papillary carcinoma is the most common form of thyroid malignancy and usually affects women of child-bearing age. Symptoms include neck swelling, goitre, horse voice, cough, haemoptysis, diarrhoea and constipation. Follicular carcinoma occurs with increased frequency in those who have had radiation exposure to the neck. Other risk factors include a family history of thyroid disease and history for goitre. Follicular carcinoma constitutes about 30% of all thyroid cancers. It has a greater rate of recurrence and metastasis than that of papillary carcinoma (the most common form of thyroid cancer). Symptoms include enlargement of the thyroid gland or neck swelling, change in voice, cough (occasionally bloody) and diarrhoea. Papillary carcinoma is the most common thyroid cancer and usually affects women of child-bearing age. Incidence: approximately in 1 in 1,000. (02 Jan 1998) |
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| thyroid carcinoma | <radiology> Papillary-follicular (75%), well-differentiated, 95% 5-yr survival with treatment, papillary may lead to neck nodes, follicular may lead to lungs, bone (haematogenous), anaplastic (20%), older patients, prognosis poor, medullary (5%), C cells, associated with pheochromocytoma (MEN-2 and MEN-3) see also: hot and cold nodules on radionuclide studies, risk factors (12 Dec 1998) |
| thyroid carcinoma risk factors | <radiology> Increased risk of malignancy: young female, male, history of radiation to head or neck, hard lesion, other neck masses, no shrinkage on TSH, family hx of thyroid carcinoma see: thyroid carcinoma (12 Dec 1998) |
| thyroid cartilage | The largest cartilage of the larynx consisting of two laminae fusing anteriorly at an acute angle in the midline of the neck. The point of fusion forms a subcutaneous projection known as the adam's apple. (12 Dec 1998) |
| thyroid colloid | The semifluid material that occupies the lumen of thyroid follicles; it contains thyroglobulin mainly. (05 Mar 2000) |
| thyroid crisis | Sudden and dangerous increase of the symptoms of thyrotoxicosis. (12 Dec 1998) |
| thyroid diverticulum | Thyroglossal diverticulum, the endodermal bud from the floor of the embryonic pharynx; the primordium of the parenchyma of the thyroid gland. (05 Mar 2000) |
| thyroid eminence | The projection on the anterior portion of the neck formed by the thyroid cartilage of the larynx; serves as an external indication of the level of the fifth cervical vertebra. Synonym: prominentia laryngea, Adam's apple, protuberantia laryngea, thyroid eminence. (05 Mar 2000) |
| thyroid foramen | An opening occasionally existing in one or both of the plates of the thyroid cartilage. Synonym: foramen thyroideum. (05 Mar 2000) |
| thyroid gland | A butterfly-shaped endocrine gland in the neck that is found on both sides of the trachea windpipe). It secretes the hormone thyroxine which controls the rate of metabolism. (27 Sep 1997) |
| thyroid gland, desiccated | The cleaned, dried, and powdered thyroid gland, previously deprived of connective tissue and fat, obtained from domesticated animals that are used for food by man, containing 0.17-0.23% of iodine in thyroid combination, occurring as a yellowish to buff-coloured amorphous powder. It was formerly used as a source of thyroid hormones in the treatment of hypothyroidism. (12 Dec 1998) |
| thyroid hormone | <endocrinology> Thyroxine and tri iodothyronine are hormones secreted by the thyroid gland in vertebrates. These iodinated aromatic amino acid compounds influence growth and metabolism and, in amphibia, metamorphosis. The hormone calcitonin which has hypocalcaemic effects is also of thyroid origin but is not usually classed with thyroxine and tri iodothyronine as a thyroid hormone. (18 Nov 1997) |
| thyroid hormone aminotransferase | <enzyme> Chemical name: 3,5-dinitrotyrosine aminotransferase Registry number: EC 2.6.1.26 Synonym: triiodothyrone aminotransferase, triiodothyronine aminotransferase (26 Jun 1999) |
| thyroid hormone resistance syndrome | <syndrome> An inherited syndrome of peripheral resistance to thyroid hormones, transmitted as an autosomal recessive trait, characterised by increased serum concentrations of thyroxine and triiodothyronine, increased thyroid hormone binding ratio, and normal to slightly increased thyroid-stimulating hormone and its response to thyrotropin-releasing hormone. The affected persons are euthyroid to slightly hypothyroid. The absence of hypermetabolism and the presence of possible hypothyroidism indicate the existence of partial resistance to the peripheral action of thyroid hormone. (12 Dec 1998) |
| thyroid hormones | Chemical substances made by the thyroid gland which is located in the front of the neck. The thyroid gland uses iodine to make thyroid hormones. 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. The two most important thyroid hormones are thyroxine (t4) and triiodothyronine (T3). (12 Dec 1998) |