The thyroid, a small butterfly-shaped organ of the body, is also the main regulator of the body’s metabolism and is the engine of the body. The thyroid gland manufactures, stores and releases thyroxine into the bloodstream to regulate the body’s metabolism. These hormones are essential for maintaining the proper functioning of all the body’s tissues and organs. More than 300 million people worldwide have thyroid disease, but most people with thyroid disease are unaware of their condition, and only 3% of patients receive regular treatment. Causes of nodules Thyroid nodules are very common in the general population. Palpable thyroid nodules are found in only about 5% of the population, mainly women. Most thyroid nodules are benign, with less than 5% being malignant. Risk is first graded by history, physical examination, thyroid ultrasonography, and functional assessment. History taking and physical examination should focus on risk factors associated with thyroid cancer, such as history of head and neck radiation exposure, history of total body irradiation before bone marrow transplantation, family history of thyroid cancer, history of nuclear exposure (before age 14), whether thyroid nodules are growing rapidly, and whether there is hoarseness, vocal cord paralysis and enlarged and fixed ipsilateral cervical lymph nodes. The size and other nature of the nodule can also be determined by ultrasound examination of the thyroid gland. If the ultrasound shows that the nodule is a substantial mass with pitting microcalcifications, irregular borders, abundant internal blood flow, infiltration of surrounding tissues, and suspicious positive lymph nodes, then these are high-risk factors indicating cancer. Clinical tests for thyroid nodules include TSH measurement, thyroid ultrasound, fine needle aspiration biopsy, and radionuclide scan. Laboratory tests include measurement of serum thyroid stimulating hormone (TSH). When the serum TSH level is below normal, a thyroid nuclear scan should be performed to understand the functional status of the nodule. If serum TSH levels are normal or above normal, thyroid ultrasonography should be performed. Radionuclide scan has been widely used in the past for the diagnosis of thyroid nodular disease, but it can only be used for the assessment of thyroid function. Fine needle aspiration biopsy (FNA) of the thyroid gland is the most accurate and effective method for evaluating thyroid nodules, but it also has a certain percentage of false negatives. Therefore, a coarse needle aspiration biopsy of the thyroid under ultrasound localization is sometimes required to further confirm the diagnosis. Even if a thyroid nodule is diagnosed as benign, patients need to be followed up because the false-negative rate of FNA can be up to 5%, which is a small but not negligible percentage of patients. Ultrasonography is recommended to follow the growth of the nodule every 6 to 18 months. The growth of the nodule itself is not necessarily an indication for malignant lesions, but it is an indication for further FNA. Treatment of thyroid nodules is based on the results of the FNA. If the cytologic result is benign, no further examination or treatment is required; if malignant, surgery is performed; if undiagnosed, repeat biopsy is performed, and if still undiagnosed, close observation or surgical excision is performed. The author is the chief physician of the Department of Otolaryngology-Head and Neck Surgery of the First People’s Hospital of Shanghai Jiaotong University, specializing in the surgical treatment of head and neck tumors, especially thyroid tumors. It is the world’s premier oncology research center and is at the forefront of clinical and basic research on thyroid tumors. Currently, our hospital is cooperating with the center in multiple aspects to fully develop surgical treatment of thyroid nodules and thyroid cancer.