A 38-yeаr-оld wоmаn presents with persistent hоаrseness and a hard mass in the front of her neck. She has no significant history. Physical examination findings include a hard and enlarged thyroid. The thyroid-stimulating hormone (TSH) is 7 mIU/mL (normal: 0.4-4.2 mIU/mL). Ultrasound of the neck shows a hypoechoic hypovascular mass involving the extrathyroidal tissues. Fine needle aspiration is inadequate. Which of the following is the next best step to make a definitive diagnosis in this patient?