The thyroid makes and stores hormones that help regulate heart rate, blood pressure, body temperature, and the rate at which food is converted into energy. Thyroid hormones also help children grow and develop. The thyroid uses iodine, a mineral found in some foods and in iodized salt, to make several of its hormones. Thyroid cancer usually responds well to treatment, and many patients can be cured. Doctors can tell the type of cancer by the way the cells look under a microscope and by the way the tumor grows.
Papillary tumors develop in cells that produce thyroid hormones containing iodine.
The cancer cells, which grow very slowly, form many tiny, mushroom-shaped patterns in the tumor. Doctors usually can treat these tumors successfully, even when cells from the tumor have spread to nearby lymph nodes. Papillary tumors account for about 60 percent of all thyroid cancers. Follicular thyroid tumors also develop in cells that produce iodine-containing hormones. These tumors have a thin layer of tissue around them, called a capsule.