Q. An 85-year-old woman presents to her primary care physician with a rapidly enlarging mass in her neck. She reports difficulty breathing, swallowing and hoarseness. The mass is firm, non-tender and fixed to the surrounding structures. The patient has a history of smoking. Physical examination reveals a large, firm, fixed, and non-tender mass in the right side of the neck which measures 8 x 7 cm. The mass is compressing the trachea, esophagus and the recurrent laryngeal nerve. The patient is referred to an endocrinologist for further evaluation. Genetic studies reveal TP53 mutation. The patient is referred to a head and neck surgeon for surgical management. What is the most likely diagnosis for this patient?