<prompt> The most common histologic type of thyroid cancer isMedullary typeFollicular typePapillary typeAnaplastic type  <response>: Papillary carcinoma accounts for 80 of all thyroid malignancies in iodine-sufficient areas and is the predominant thyroid cancer in children and individuals exposed to external radiation. The incidence of primary malignant tumours of the thyroid gland Also, remember - Thyroid carcinoma is the most common malignancy of the endocrine system Ref : Schwaz 9e p1361 