A 75-year-old lady is diagnosed of having a thyroid malignancy. Her serum calcium is low. What is the most likely explanation?: (A) She has developed metastasis of the parathyroid, (B) She has follicular carcinoma, (C) She has papillary carcinoma, (D) She has medullary carcinoma
Answer is D. It originates from parafollicular cells that produce calcitonin. 3rd most common thyroid cancer. Calcitonin-highly sensitive marker. For screening. Differential diagnosisi. Prognosis. Assessment of treatment response.