Benign thyroid enlargement (non-toxic multinodular goiter)
GoiterGoiter - enlarged thyroid is an enlargement of the thyroid gland. The gland can be generally enlarged or have multiple growths (nodules) leading to enlargement of the whole thyroid gland. The latter is termed multinodular goiter (MNGMNG - Multinodular goiter; enlarged thyroid that contains multiple nodules). There are two forms of multinodular goiter: 1) nontoxic MNGNontoxic MNG - multinodular goiter that produces normal levels of thyroid hormone and 2) toxic MNG. If the goiter makes normal amounts of thyroid hormone, it is known as a nontoxic MNG. If the goiter makes higher than normal amounts of thyroid hormone leading to a suppressed TSHTSH - Thyroid stimulating hormone; also known as thyrotropin. The hormone that causes the thyroid to make and release thyroid hormone, it is known as a toxic MNG. (See Hyperthyroidism) The exact causes of thyroid nodules or multinodular goiters are unknown. In general, the development of goiter is due to a complex mix of genetic and environmental factors. Iodine deficiency as a cause of goiter is rare in North America and most of Europe. However, even in areas of iodine deficiency most patients do not develop goiters.