I. What is a thyroid nodule? The thyroid gland is an endocrine organ in the neck of the human body. A thyroid nodule is a mass with one or more abnormal tissue structures in the thyroid gland due to various reasons, which, to put it plainly, is an abnormal mass in the thyroid gland. II. Are there many people with thyroid nodules? Thyroid nodules are very common, with a detection rate of 3% to 7% by palpation in the general population, and up to 20% to 76% by high-resolution ultrasound. Among them, 5%-15% of thyroid nodules are malignant, i.e. thyroid cancer. The clinical management of benign and malignant thyroid nodules is different, and the impact on patients’ quality of life and the medical costs involved are also significantly different. Therefore, the management of thyroid nodules should first determine their nature and identify their benign and malignant nature. How to identify the nature of thyroid nodules and distinguish their benign and malignant nature? The following cases are more likely to be benign: 1. Hashimoto’s thyroiditis 2. family history of goiter 3. symptoms of hyperthyroidism or hypothyroidism 4. painful nodules or soft nodules