What types of thyroid cancer are there?
Most thyroid cancers are well differentiated and have an excellent prognosis after surgical removal. Papillary cancer is the most common type, accounting for 80%, and pure follicular cancer is the second most common type, accounting for 10% to 15%. Medullary thyroid carcinomas arise from the parafollicular or C cells of the thyroid gland, account for approximately 5% of thyroid cancers, and are most likely to occur sporadically although they are seen with increased frequency in patients with MEN IIB syndrome. The more aggressive thyroid cancers, such as poorly differentiated and anaplastic cancers, are the least common and have a poor prognosis.