<prompt> Which of the following is the commonest tumour of thyroid -Anaplastic carcinomaFollicular carcinomaPapillary carcinomaMedullary carcinoma  <response>: Ans. is c i.e., Papillary 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. - SchwartzIncidence of primary malignant tumors of thyroid gland Harrison 17eType of thyroid carcinomaApproximate PrevalencePapillary Carcinoma80-90Follicular Carcinoma5-10Medullary Carcinoma10Anaplastic CarcinomaRareLymphomas1-2 Also rememberThyroid carcinoma is the most common malignancy of the endocrine system Ref: Harrison, 17e, p 2243 