Ans. is A ie. total thyroidectomy with neck dissection The finding of amyloid in the stroma of a thyroid nodule is diagnostic of medullary carcinoma because medullary carcinoma is the only thyroid tumor that contains this substance. Medullary carcinoma can also be diagnosed by finding an increased Serum Calcitonin* level in conjunciton with thyroid mass. Treatment ? Because medullary Ca are C-cell tumors*, they do not respond to thyroxine therapy and do not concentrate radioiodine. They are relatively insensitive to external radiation and surgery offers the only chance for cure. Total thyroidectomy is performed because of frequent multicentricity, recurrences have occured when thyroid tissue is left. Single or bilateral neck dissection is the t/t of choice when neck nodes are clinically involved.