Q. A 35-year-old female presents to her primary care physician with a two-month history of anxiety, palpitations, weight loss, and heat intolerance. She reports that she has been feeling "on edge" and is having trouble sleeping at night. She has also lost 10 pounds in the last two months despite an increased appetite. Her temperature is 37.5 degrees Celsius, heart rate 110/min, blood pressure is 130/80 mm Hg, and her respiratory rate is 18/min. On physical examination, the patient has diffuse goiter and exophthalmos. Her thyroid is slightly tender to palpation and there is a mild increase in her reflexes. Laboratory tests reveal elevated free T4 and free T3, and suppressed TSH. The patient's TSH receptor antibody and thyroid peroxidase antibody levels are also elevated. A biopsy of the thyroid gland is performed and shows hyperplastic folds of tall epithelial cells with clear vacuoles, creating "scalloped" edges, and infiltration of B-cells and T-cells in the stroma with scant colloid. What is the most likely diagnosis for this patient?