Simultaneous occurrence of medullary and papillary carcinoma of the thyroid gland identified by fine needle aspiration - A case report

BACKGROUND: Fine needle aspiration (FNA) diagnosis of simultaneous medullary and papillary thyroid carcinoma in independent thyroid lobes is exceedingly rare. CASE: A 36-year-old female presented with a one-month history of dysphagia. Thyroid ultrasound revealed a multinodular goiter. She was clinically and biochemically euthyroid. FNA of the right thyroid nodule was consistent with medullary carcinoma, and FNA of the left thyroid lobe was consistent with papillary carcinoma. Immunohistochemistry revealed strong calcitonin and CEA positivity in the right lobe and lack of staining in the left lobe. Conversely, staining for thyroglobulin was negative on the right lobe and positive on the left lobe. CONCLUSION: The patient developed tumors in separate lobes of the thyroid. Immunoreactivity of calcitonin, CEA and thyroglobulin made a sharp distinction between the two tumors. Therefore, we conclude that these tumors were not linked by either embryology or genetics.