Topic Overview

There are different types of thyroid cancer. They are based on what the cells look like under a microscope. Your treatment will depend on which type of thyroid cancer you have.

• Papillary thyroid cancer (PTC). This is the most common type of thyroid cancer and is most commonly diagnosed in people who are in their 30s and 40s. PTC starts in cells called follicular cells and usually is only found in one lobe of the thyroid. Although PTC usually grows very slowly, it often spreads to lymph nodes in the neck. It can also spread to the lungs and bones.
• Follicular thyroid cancer (FTC). This is the second most common type of thyroid cancer and is most commonly diagnosed in people who are in their 50s. It is usually found in countries where people do not get enough iodine from food. FTC usually remains in the thyroid but can spread to the lungs.
• Medullary thyroid cancer (MTC). Medullary thyroid cancer is less common. By the time it is diagnosed, it may already have spread to the liver, lungs, and lymph nodes. There are two types of MTC: sporadic and familial.
  • Sporadic MTC occurs mostly in adults, does not occur in families, and usually affects only one lobe of the thyroid gland.
  • Familial MTC can develop during early childhood, occurs in families, and can spread to other parts of the body. There are three types of familial thyroid cancer, called MEN 2a, MEN 2b, and FMTC (familial medullary thyroid cancer). Genetic blood tests can be used to identify people who are at risk for developing familial medullary cancer. If genetic testing shows a gene problem called RET mutation, most experts suggests surgery to remove the thyroid to help prevent future medullary thyroid cancer.
• Anaplastic carcinoma. This is a very rare and aggressive form of thyroid cancer. By the time it is diagnosed, it usually has spread to the neck and other parts of the body. It grows rapidly and is the most fatal form of thyroid cancer. Anaplastic carcinoma is more common in women older than 50.
• Thyroid lymphoma. This very rare type of lymphoma starts in the thyroid gland and causes it to grow larger.