In non-iodine-deficient areas, thyroid nodules are palpable in 3% to 7% of the population. If high-resolution ultrasound is used, thyroid nodules can be detected in 20% to 70% of people. The detection rate of thyroid nodules in autopsy is also as high as 65%. Therefore, thyroid nodules have become a common disease. However, thyroid nodules are mostly benign masses, and malignant nodules account for only about 5% of thyroid nodules. If all thyroid nodules are surgically removed, then 95% of patients suffer unnecessary surgery. Therefore, the identification of benign and malignant thyroid nodules is very critical. Common causes and classification of thyroid nodules 1, nodular goiter: common. Iodine deficiency, people in puberty, pregnancy will cause absolute and relative shortage of thyroid hormone, in this case there will be a goiter, called simple goiter (iodine deficiency caused by commonly known as big neck disease), initially diffuse enlargement of the thyroid gland, but with the onset of the time gradually prolonged, there will be nodules in the thyroid tissue. This is when a simple goiter becomes a nodular goiter. The disease is characterized by the fact that most people start with a simple goiter with multiple lumps. Generally, the disease does not need surgical treatment. Surgical treatment is needed when combined with hyperthyroidism, lumps produce pressure symptoms and cancer. 2.Thyroid adenoma: more common, benign thyroid tumor, with certain malignant rate. The lumps are different from nodular thyroid lumps, most of which are single, round, unchanged for many years, asymptomatic and with smooth surface. If it enlarges rapidly in a short period of time, or if it develops pressure symptoms, such as difficulty in breathing, hoarseness, and difficulty in swallowing, it may be cancerous. If there is a sudden increase in size and pain, there may be intracapsular hemorrhage of thyroid cystic adenoma. 3.Thyroid cancer: rare. The most common thyroid cancer is papillary adenocarcinoma of thyroid, accounting for 60%, and the prognosis is very good if handled timely and properly. Follicular carcinoma of thyroid, accounting for 20%, has a good prognosis. Medullary carcinoma of thyroid is rare, accounting for 5%, with poor prognosis. Undifferentiated carcinoma of thyroid is rare, accounting for 5%, with poor prognosis, and other carcinomas such as lymphoma account for 5-10%. Cancer is characterized by rapid growth, hard mass, unclear boundary, poor mobility, often with compression symptoms, such as dyspnea, hoarseness, dysphagia, etc., and enlarged lymph nodes around the neck. Thyroid hormone T3, T4 has no big changes, thyroid hormone is not low or slightly high, ultrasound can be seen in hypoechoic nodules, irregular edges, no obvious envelope, rich blood flow, there are small or coarse calcification of strong echoes. 4, inflammatory nodules: acute suppurative thyroiditis, subacute thyroiditis, chronic lymphocytic thyroiditis can appear nodules. Acute suppurative thyroiditis is characterized by redness, swelling, heat and pain. Subacute thyroiditis has a history of epiglottitis followed by pain in the thyroid region. Chronic lymphocytic thyroiditis has a long history and is often associated with hypothyroidism, which can be differentiated by a decrease in basal metabolic rate and iodine uptake in I131, or by fine-needle aspiration pathology if differentiation is difficult. Treatment of thyroid nodules 1, larger nodules appear pressure symptoms, such as dyspnea, hoarseness, dysphagia, etc., generally need surgical treatment, because of the ineffectiveness of internal medicine. 2.Larger nodules affecting the appearance generally require surgical treatment. 3. Thyroid nodules smaller than 1cm generally do not require surgical treatment and can be followed up for observation. Thyroid nodules smaller than 1cm if accompanied by the following conditions: (1) history of radiation exposure to the neck, (2) family history of thyroid cancer, (3) ultrasound has a hypoechoic solid mass or accompanied by lymph node enlargement, etc., then need further examination and evaluation, 4. Then further examination and evaluation are required. 4. Thyroid nodules larger than 1 cm need to be examined and evaluated with the following items: (1) Thyroid-stimulating hormone (TSH) test should be done first, and if it is lowered, a nuclear scan should be done, and if it is a high-functioning nodule (that is, one that is combined with hyperthyroidism), it should be directly removed surgically. (2) Puncture cytology: if malignant or suspected malignant, direct surgery is recommended. If it is benign, then follow up and observe, during the follow up, the physician can use palpation and ultrasound to observe whether there is any change in the size of the nodule, etc. Within 1-2 years of observation, if the nodule grows significantly (i.e., more than 50% of the original volume), then perform puncture cytology again, and if it is malignant or suspected of malignant, then direct surgery is recommended. If the nodule is malignant or suspected to be malignant, surgery is recommended. If the nodule is still benign, surgery is also considered if there are symptoms of pressure and cosmetic problems, and if there are no symptoms of pressure and cosmetic problems, surgery is also considered, and the nodule is kept under observation. If a puncture-confirmed benign nodule does not change within 1-2 years of follow-up, it should be followed up every 2 years or so. If the first puncture cytology is inconclusive, repeat puncture is recommended, and if the result of repeat puncture is malignant or suspected to be malignant, direct surgery is recommended. If the second puncture is still inconclusive, surgery is recommended, or a period of close observation may be necessary. If the result of re-puncture is benign, it should be handled according to the method mentioned above. There is a special case: if the puncture is a follicular adenoma, continue to perform a nuclear scan, and if it is a cold nodule, operate. If it is a hot nodule, observe. (3) multiple nodules, do thyroid stimulating hormone (TSH) test, if lower, should do a nuclear scan, if the high-functioning nodules (that is, combined with hyperthyroidism nodules), directly to be operated. In other cases, puncture should be performed on large nodules or nodules suspected to be cancerous under ultrasound, and then according to the results of puncture, the patient should be treated according to the above methods. Puncture cytology is the most accurate way to diagnose thyroid nodules. In the American guidelines for the treatment of thyroid nodules, it is necessary to puncture the nodules before considering surgery, but it is sometimes impossible to do so in our country due to the limitation of conditions. However, in our country, due to the limited conditions, it is sometimes impossible to do so. Therefore, if the following cases are considered to have a high possibility of malignancy, surgery can be performed directly. (1) there is a family history of thyroid cancer, (2) there is a history of radiation exposure to the neck, (3) the mass increases rapidly, the mass is hard, the border is unclear, poor movement, and there are symptoms of compression, such as dyspnea, hoarseness, and dysphagia, etc., (4) ultrasound can see hypoechoic solid nodules, irregular edges, no obvious peripheral membrane, rich blood flow, and there are fine or coarse calcified strong echoes or accompanied by enlarged lymph nodes.