There are 4 main types of thyroid cancer. These are named after the cell type in which the cancer first develops: 

• Papillary thyroid cancer is the most common type of thyroid cancer, making up about 70–80% of thyroid cancers^[1][2]. It usually grows in one side (lobe) of the thyroid gland^[3] but often spread to the lymph nodes in the neck^[4]. 
• Follicular thyroid cancer is the next common type of thyroid cancer, making up about 10– 20% of thyroid cancers^[5]. It usually does not spread to the lymph nodes, but can spread to other parts of the body, such as the lungs or bones^[6]. 
• Medullary thyroid cancer makes up about 4% of thyroid cancers. It can sometimes spread to lymph node, the lungs or liver^[7]. Medullary thyroid cancer can be inherited or occur in people with no family history of the cancer^[8]. 
• Hürthle (Hurthle) cell cancer (also called oxyphil cell carcinoma) is less common, and makes up about 3% of thyroid cancers. It is harder to find and treat^[9]. 
• Anaplastic thyroid cancer (also called undifferentiated carcinoma) makes up about 2% of thyroid cancers. It may develop from existing papillary or follicular cancer. It can spread quickly into the neck and other parts of the body^[10]. 

Other rare types of cancer can occur in the thyroid gland, such as thyroid lymphoma, and thyroid sarcoma. Cancer can also occur in the parathyroid glands, which are 4 small glands attached to the thyroid gland^[11]. Parathyroid cancers are very rare. This information on thyroid cancer does not cover parathyroid cancer.