Q. A 65-year-old woman with a history of childhood irradiation presents to her primary care physician with a slowly growing mass in her neck. On examination, the mass is palpable and there is significant cervical lymphadenopathy. The patient is sent for fine needle aspiration of the mass, which returns positive for cells with empty-appearing nuclei with central clearing. Additionally, psammoma bodies and nuclear grooves are present. Genetic testing reveals RET/PTC rearrangements and BRAF mutations. What is the most likely diagnosis?