Cancer of the thyroid gland. The thyroid is a gland in the front of the neck just below the Adam's apple. The thyroid produces thyroid hormone that regulates blood pressure, heart rate, and temperature. There are multiple types of thyroid cancer, depending on which cells of the thyroid are growing out of control including: papillary thyroid cancer, follicular thyroid cancer, medullary thyroid cancer, anaplastic thyroid cancer, and thyroid lymphoma. Thyroid cancer is rare but is more common in patients exposed to large doses of radiation or with a family history of enlargement of the thyroid (goiter).