How to distinguish good from bad thyroid nodules The thyroid gland is the largest endocrine gland in the body, weighing about 20 to 25 grams. Its main function is to synthesize thyroid hormones to regulate the body’s metabolism of materials and energy as well as growth and development. With the accelerated pace of life, improved treatment technology and increased concern for people’s health, the incidence of thyroid disorders is not gradually increasing. Functional changes such as hyperthyroidism and hypothyroidism are detected early due to obvious clinical symptoms, while organic changes such as goiter, thyroid nodules and thyroid tumors are often confusing due to their insidious and asymptomatic nature, and there are many different opinions on whether to stay or go. The most common thyroid abnormality is the thyroid nodule. This is the easiest lesion to detect clinically and is also the most confusing. In fact, thyroid nodules are very common in the population, accounting for 30-70% of the population, and are especially common in older women. Ultrasonography is the most direct and sensitive diagnostic tool, and fine needle aspiration is the most effective means of differentiation. Benign thyroid nodules tend to show slow growth, uniform texture, good mobility, smooth surface, no lymph node enlargement, cystic changes, and no calcification. Although calcification needs to be alerted for malignancy, it should not be taken as an indication of malignancy. Only irregular or punctate calcification should be considered as a possibility of malignancy. If a thyroid nodule grows rapidly in a short period of time, has an irregular shape, is accompanied by enlarged and fused lymph nodes, involves surrounding tissues, and presents with hoarseness and neck discomfort, one should be alert to the possibility of malignancy and malignant changes. Fine needle aspiration of the thyroid gland is a commonly used clinical tool to identify benign and malignant thyroid nodules, and can detect malignant thyroid changes in more than 80% of cases. If necessary, thyroid scans and hematology tests can be used to confirm malignant changes in about 90% of cases before surgery. Therefore, if a thyroid nodule is found clinically, there is no need to be nervous, neither to be rash nor to be left alone. According to statistics, more than 95% of thyroid nodules are benign changes, and even if they are malignant changes, most thyroid cancers develop slowly, called malignant changes, and benign progression, and even some microscopic cancers can accompany the whole life without affecting the life expectancy. Clinically, the treatment plan is determined mainly by ultrasound features, puncture results and progression. If the change is benign, follow-up is sufficient. If malignancy is suspected, repeated punctures or elective surgery can be performed. If malignancy is determined, the scope of surgery is determined according to the degree of malignancy, whether isotope therapy or radiotherapy, and the prognosis is good. Only very rare undifferentiated and medullary carcinomas develop rapidly, and other rare thyroid lymphomas may be treated with chemotherapy after diagnosis.