For patients with thyroid cancer, the most common clinical manifestation is thyroid nodules, and most patients do not have obvious clinical symptoms, only being incidentally discovered during physical examinations. In rare cases, patients may seek medical attention due to enlarged cervical lymph nodes. As the condition progresses, the neck mass gradually enlarges, becomes firmer, and its mobility decreases during swallowing. In some rapid developments, it may invade surrounding tissues, leading to late-stage symptoms such as hoarseness, difficulty breathing, and difficulty swallowing. When the cervical sympathetic nerve is compressed, it can cause pain in the ears, occipital region, and shoulders. In the case of medullary carcinoma, which can produce serotonin and calcitonin, patients may sometimes experience symptoms such as diarrhea, palpitations, facial flushing, or decreased blood calcium levels.