Thyroid neoplasms

A 43-year-old female presents to her primary care physician complaining of a gradually enlarging neck mass. She reports that she first developed a firm nodular midline mass on the anterior aspect of her neck two months ago. She is otherwise healthy and takes no medications. A fine-needle aspiration is performed and a histological sample of the specimen is shown. Which of the following is the most likely diagnosis?

A 25-year-old man presents with a mass on his neck. He says that he first noticed the mass a few weeks ago while taking a shower. Since then, the mass has not increased in size. He denies any pain or difficulty in swallowing. Past medical history is unremarkable. Family history is significant for his father who had his thyroid removed when he was around his age but doesn’t know why. Review of systems is significant for occasional episodes of anxiety that include a pounding headache, racing heart, and sweating. His vital signs include: pulse 88/min, blood pressure 133/87 mm Hg, temperature 37.2°C (99.0°F), and respiratory rate 14/min. He is 183 cm (6 ft 2 in) tall with long extremities. On physical examination, the patient appears cachectic. There is a palpable 4 cm x 4 cm nodule present on the left lobe of the thyroid. Which of the following is the most likely thyroid pathology in this patient?