What is thyroid cancer?

The thyroid gland is a small, butterfly-shaped gland located in the neck, below the Adam's apple. The thyroid gland produces the hormones thyroxine (also called T4) and triiodothyronine (also called T3). These hormones play a role in certain bodily functions, including body temperature, mood and excitability, pulse rate, digestion and others.

Sometimes thyroid tissue begins to grow uncontrollably, which can cause one or more nodules (growths) to form in the thyroid. The reason why this happens is unknown. Cancer is the biggest worry when nodules form. Cancerous nodules can invade the tissues of the neck, spread to the surrounding lymph nodes, or to the bloodstream, and then to other parts of the body.

There are four types of thyroid cancer:

  • Papillary: This is the most common type: more than 70 percent of thyroid cancers are papillary. This cancer usually does not grow very fast and does not spread quickly into surrounding tissue.
  • Follicular: This type makes up 10 to 15 percent of thyroid cancers. Follicular cancer can travel through the bloodstream and into other areas of the body, such as the lungs or bone.
  • Medullary: This type accounts for 4 percent of thyroid cancers. It is more likely to develop if there is a family history (others in the family have it) of this type of cancer.
  • Anaplastic: This type is rare (about 2 percent of thyroid cancers). Anaplastic cancer is a fast-growing cancer, spreading quickly into surrounding tissue. Treatment is the least effective in this type of cancer.

What are the symptoms of thyroid cancer?

In most cases, there are no signs or symptoms in the early stages of thyroid cancer. Having one or more of the following symptoms does not necessarily mean that you have thyroid cancer; other conditions can cause these symptoms. However, one or more of these symptoms might occur as thyroid cancer grows:

  • Lump in the neck
  • Pain in the lower front part of the neck
  • Trouble breathing
  • Trouble swallowing
  • Hoarseness
  • Swollen lymph nodes, especially in the neck

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy