The vast majority of thyroid nodules are benign, but those with the following manifestations should be alerted to the possibility of malignant nodules: 1. In non-endemic areas with endemic goiter, 10% to 50% of single thyroid nodules in children under 14 years of age are malignant. However, all are well-differentiated papillary thyroid carcinomas. 2.Single nodule in the thyroid gland in adult males. 3.Thyroid nodules that have existed for many years and have increased significantly in a short period of time. 4.The chance of a single nodule becoming cancer is much higher in patients living in coastal areas than in patients from endemic goiter areas. Patients who have received radiation therapy to the head and neck during childhood should be more suspicious of a single nodule in the thyroid gland. The nodules are hard, irregularly fixed or accompanied by enlarged ipsilateral cervical lymph nodes and vocal cord paralysis. 7. Neck radiograph shows cloudy or granular shadows of calcification in the thyroid gland. The border is irregular. The tracheal stenosis caused by thyroid cancer is often normal in left and right diameter, and anterior and posterior diameter can be normal. 8.B ultrasound examination shows solid or cystic solidity with uneven internal echogenicity, unclear and irregular boundary. Especially with sand granules, calcified foci, abundant or abnormal blood flow. 9.Tumor cells are found by puncture examination, and the aspirate of cystic masses may gradually turn dark red, which is a characteristic of metastatic foci of papillary thyroid cancer. The diagnosis of thyroid cancer is valuable in early stage. Any isolated thyroid nodules found should be clinically excluded from thyroid cancer. If the nodule is hard and uneven, accompanied by enlarged cervical lymph nodes, paralysis of the recurrent laryngeal nerve or a history of previous neck reflexes, the possibility of cancer is high. Similarly, if one of the multiple nodules in the thyroid gland is particularly prominent and hard, thyroid cancer should be suspected. In addition, if the thyroid itself appears asymmetrically enlarged or hard nodules that are rapidly increasing in size or are fixed, thyroid cancer should be considered.