Most of the benign thyroid tumors are isolated thyroid nodules, except for functional autonomic thyroid tumors, and a few are multiple nodules. Most of them are found in a few months to several years or even longer due to slight discomfort or a lump of more than 1cm or even larger, or they are found without any symptoms during routine physical examination by ultrasound. Most of them are single, round or oval, with smooth surface, clear boundary, firm texture, no adhesion with surrounding tissues, no pressure pain, and can move up and down with swallowing. The tumor is usually a few centimeters in size, and huge ones are rare. Huge tumors can produce compression of adjacent organs, but do not invade these organs, such as compression of trachea and displacement of organs. In some cases, the tumor may suddenly increase in size due to intra-tumor hemorrhage with local swelling and pain. Most patients have a long history of thyroid nodules and are asymptomatic in the early stage or have only mild panic attacks, weight loss and weakness. 3. Some thyroid adenomas can become cancerous, with a cancer rate of 10-20%. The possibility of carcinoma should be considered if the following conditions are present: (1) the tumor has increased rapidly recently; (2) the tumor is restricted or fixed; (3) hoarseness, difficulty in breathing and other pressure symptoms appear; (4) the tumor is hard and solid with rough and uneven surface; (5) the lymph nodes in the neck are enlarged.