What are thyroid cysts?

A thyroid cyst is a fluid collection lined by epithelial cells. This may be a part of a larger structure that would be concerning for cancer. 

Thyroid cysts are fluid-filled sacs that can develop in the thyroid gland. The thyroid gland is a small organ in the neck that secretes hormones that regulate the speed of chemical processes in the body (known as the metabolic rate). Thyroid cysts, a type of thyroid nodule or lump, are usually fairly small, ranging in size from less than a third of an inch across to an inch across, or larger in rare cases. The fluid-filled cysts are usually benign or noncancerous, but occasionally they contain solid material in addition to the fluid, and this may be cause for concern.

Continue Learning about Thyroid


A member of our endocrine system, the thyroid gland produces hormones that help control many of our body functions, such as weight and temperature.Located at the base of our neck, this butterfly-shaped gland makes several hormones...

, which are collectively known as thyroid hormones. These hormones are especially key in the brain development of infants and children. Thyroxine, also known as T4, is the primary hormone secreted by the thyroid gland; this hormone helps control our metabolism, a chemical process that turns our food into energy. A lack of iodine in your food can cause the thyroid to swell, a condition called a goiter. Several other disorders and diseases can affect this gland, including cancer. If you notice swelling in your neck or feel a lump, make sure you see your doctor; this could indicate a problem with this important gland.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.