ABSTRACT
Q1 A 17-year-old male is being evaluated for a thyroid nodule. During questioning, he admits to recently having headaches and anxiety. After the administration of pentagastrin, his serum calcitonin is 1500 pg/mL. A fine needle aspiration (FNA) of the nodules is performed. What measurement on the FNA sample would aid in making the diagnosis? A calcitonin B vanillylmandelic acid (VMA) C carcinoembryonic antigen D A and C E all of the above
A1 D This question describes a typical case of medullary thyroid carcinoma (MTC), with a multinodular thyroid in the setting of an elevated calcitonin level. MTC originates from the parafollicular C cells and is responsible for 5% of all thyroid malignancies. Eighty per cent of medullary carcinomas are sporadic and the remainder are associated with an inherited multiple endocrine neoplasia (MEN) syndrome. Pathological diagnosis can be obtained with FNA. The pathological features of medullary carcinoma include C-cell hyperplasia, presence of amyloid, and specimen staining positive for calcitonin and carcinoembryonic antigen.
