Thyroid cancer is a common malignant tumor in the head and neck area. The early symptoms of thyroid cancer are highly atypical, and many patients do not present clear early symptoms. Often, patients discover painless nodules in the thyroid incidentally during physical examinations; these nodules can move up and down with swallowing motions. In a minority of cases, when the nodules of early-stage thyroid cancer are large, they can cause hoarseness or coughing and choking when drinking water. Some patients might experience intermittent, hidden pain in the thyroid area during the early stages, which often resolves on its own without treatment. Besides these, in its early stages, thyroid cancer may not present other obvious symptoms. As the condition progresses, significant clinical symptoms appear only when the tumor invades surrounding structures or metastasizes to distant sites.