What are thyroid nodules?A thyroid nodule is an abnormal growth (lump) of thyroid cells within the thyroid gland.
The thyroid is a hormone-producing, butterfly-shaped organ (or gland) that is located on the front of the neck, just under the Adam's apple (the larynx). The thyroid gland, which is made up of a right lobe and a left lobe, produces and secretes thyroid hormones into the bloodstream. Thyroid hormones govern functions such as body temperature, digestive and heart functions, and all body processes needed for life.
What causes a thyroid nodule to form?Sometimes thyroid tissue begins to grow, causing one or more nodules to form. The reason why this happens is unknown. Cancer (malignancy) is the biggest concern when nodules form. Fortunately, cancer is very rare – found in less than 5 percent of all nodules. Nodules develop more often in those with a family history of nodules and in individuals with iodine deficiency. Iodine is needed to make thyroid hormone.
There are different types of thyroid nodules.
- Colloid nodules. These are one or more overgrowths of normal thyroid tissue. These growths are not cancerous (benign), may grow large, but do not spread beyond the thyroid gland.
- Thyroid cysts. These are fluid-filled or partially solid/partially fluid-filled growths inside the thyroid gland.
- Inflammatory nodules. These nodules develop as a result of chronic inflammation of the thyroid gland. These growths may or may not cause pain.
- Multinodular goiter. Sometimes an enlarged thyroid (goiter) is composed of many, usually benign, nodules.
- Hyperfunctioning thyroid nodules. These nodules produce thyroid hormone, which may lead to the development of hyperthyroidism. Hyperthyroidism can affect the heart, leading to such complication as sudden cardiac arrest, hypertension, arrhythmias; as well as osteoporosis and other health problems.
- Thyroid cancer. Of the nodules that can form as the thyroid gland enlarges, fortunately, less than 5 percent are cancerous.