At a Glance McCune-Albright Syndrome (MAS) is a triad of bone lesions (polyostotic dysplasia), brown nonelevated pigmented areas of skin (cafe-au-lait spots),and endocrine dysfunction (usually precocious puberty). The disease is not inherited and is due to a post-zygotic activating mutation in the GNAS1 (alpha subunit of the G protein stimulating adenylate cyclase) gene. Since it…
At a Glance Thyroid stimulating hormone (TSH) secreting pituitary adenoma (TSH-oma) or central hyperthyroidism is very rare and has a prevalence of about one case per million. These comprise about 1% of pituitary adenomas. Most patients are middle aged, although the condition has been documented over a wide age range (8-80 years of age). The…
At a Glance Although the most common cause of an elevated HCG level in females is pregnancy, occasionally, a HCG-secreting tumor is suspected and other conditions such as gestational trophoblastic disease (GTD), nontrophoblastic neoplasms, or a pituitary source of HCG, must be considered. The clinical description of the various trophoblastic and nontrophoblastic conditions is discussed…
At a Glance Factitious thyrotoxicosis may result from accidental, iatrogenic, or surreptitious ingestion of thyroid hormones, enough to cause symptoms of hyperthyroidism. It usually refers to the intentional ingestion of levothyroxine (T4) tablets, accidentally following ingestion of bovine thyroid extract in ground beef (T4 and T3), or, rarely, ingestion of T3 tablets in countries in…
At a Glance Ectopic thyroid is defined as any thyroid tissue not located in its usual position (i.e., anterior and lateral to the second, third, and fourth tracheal rings). During development, the thyroid gland descends from the foramen cecum at the base of the tongue to its location at the front of the trachea. This…
At a Glance Painless thyroiditis (silent thyroiditis) is characterized by the transient onset of symptoms of thyrotoxicosis, followed by a resolving hypothyroidism. Pain and tenderness of the thyroid are usually absent. Any symptoms of thyrotoxicosis, such as jitteriness, increased perspiration, easy fatigability, heat intolerance, tachycardia, and muscle weakness, can be present. Usually, symptoms are mild…
At a Glance Struma ovarii usually refers to the presence of significant amount of thyroid tissue in ovarian tumors, typically monodermal teratomas. Although a small amount of thyroid tissue may be present in up to 15% of ovarian teratomas, in only 1-2% of teratomas does thyroid tissue comprise more than 50% of the teratoma: thus…
At a Glance Resistance to thyroid hormone (RTH) is characterized by a reduced responsiveness of target tissues to endogenous thyroid hormones. It is an autosomal dominant disorder with an incidence of about 1 in 40,000 live births. Patients are usually identified by a combination of elevated FT4 and FT3, normal or slightly increased TSH, and…
