The thyroid is a butterfly-shaped gland in your neck just below the larynx (voice box). It produces hormones that control your heart rate, body temperature, growth and metabolism (how quickly food is changed into energy). The parathyroid glands (not shown), which are four pea-sized organs on the back of the thyroid, produce hormones controlling blood calcium levels.
The primary types of thyroid cancer are anaplastic, follicular, medullary and papillary, which is the most common. Papillary and follicular are sometimes referred to as differentiated thyroid cancers and are staged as such. Their cells look similar to normal cells when viewed under a microscope, and they tend to spread and grow slowly. In contrast, medullary and anaplastic thyroid cancer cells are undifferentiated or poorly differentiated, meaning they don’t resemble normal thyroid cells. Both tend to grow and spread more quickly, and anaplastic thyroid cancer is very aggressive.
Symptoms may include a lump, swelling or pain in the front of the neck; hoarseness or other voice changes that don’t go away; trouble swallowing or breathing; or a constant cough not related to a cold.