This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Occult thyroid malignancy with nodal metastasis is seen in - \nSelect and explain. \nA. Medullary carcinoma, B. Follicular ca, C. Papillary ca, D. Anaplastic ca', 'role': 'user'}, {'content': 'Answer: C \nExplanation: A small percentage of cancers present with enlarged lymph nodes in the jugular chain or pulmonary metastases with no palpable abnormality of the thyroid.\nThe primary tumor may be no more than a few millimetres in size and is termed occult. Such primary foci of papillary carcinoma may also be discovered in thyroid tissue resected for other reasons.\nThe term occult was formally applied to all papillary carcinomas less than 1.5 cm in diameter but the preferred terminology now is microcarcinoma for cancers less than 1 cm in diameter.\nThese have an excellent prognosis although those presenting with nodal or distant metastases justify more aggressive therapy". - Love & Bailey', 'role': 'assistant'}]