Thyroid nodules in children: 1. Prevalence: The prevalence of palpable thyroid nodules in children in the United States is about 2%, with an annual incidence of 7/1000 (1975). The prevalence of ultrasound thyroid nodules in children in China is 7.04%, with multiple nodules accounting for 66.7% and a male to female ratio of 1:1.4. Most malignant thyroid nodules in children are differentiated thyroid carcinomas, with medullary carcinomas accounting for 5%, and the incidence of nail cancer is higher in women than in men over the age of 10. 2. Diagnosis: (Same as adults) (1) Caution in performing CT examination of the neck, which may increase the chance of malignant nodules. (2) Malignant thyroid nodules in children can be as high as 20%, which is higher than that in adults. 3. Treatment: Surgery is the main treatment for malignant and suspected malignant thyroid nodules in children. Children with malignant thyroid nodules are often multifocal and have a higher chance of lymphatic metastases and distant metastases; therefore, total or near-total thyroidectomy should be performed, followed by 131I therapy. Children with thyroid nodules who have a family history of MTC or MEN2 type are recommended to be tested for RET mutations, and those who are positive have a significantly higher incidence of MTC and should undergo prophylactic total thyroidectomy. Children with malignant thyroid nodules have a good prognosis even with metastases, with long-term survival rates of more than 90% for DTC, 5 years for MTC, more than 85% for 10 years, and about 15% for 30 years. The recurrence rate is 10% to 35%.