Thyroid nodules are a very common condition. They can be benign swellings such as thyroid adenoma, nodular goiter, or thyroid cancer, and we refer to these thyroid swellings collectively as thyroid nodules until the nature of the disease is determined by pathology. Thyroid nodules are classified as solid, cystic, or cystic-solid, and can be solitary or multiple. Thyroid nodules are more common in women than in men, and more common in middle-aged and older people than in teenagers. Large thyroid nodules can be detected by the naked eye alone, some by palpation, and nowadays many are detected by ultrasound during routine medical examinations. Due to the widespread use of high-resolution ultrasound instruments, the detection rate of thyroid nodules is quite high, but most of them are benign lesions, commonly known as nodular goiter or goiter. It should not be overlooked, however, that about 10% of thyroid nodules are malignant lesions. Since thyroid nodules can be both benign and malignant, and the prognosis for benign and malignant nodules varies greatly, it is important to consult a thyroid specialist after finding a thyroid nodule to decide whether to continue observation or to treat it surgically to avoid missing the cancer.