Thyroid grade 4B refers to the results of thyroid nodules detected by ultrasound. Thyroid nodules can be divided into grades 1-6. The probability of malignancy of thyroid nodules below grade 3 is low, and the probability of malignant lesions is higher when there are results of grade 4 and above, while the probability of malignancy of grade 4B is 45%-75%, so the situation is more serious. It is necessary to go to the hospital for ultrasonography, puncture cytology, etc. to clarify the nature and then treat. grade 4B thyroid nodules may appear as follows: 1. papillary thyroid cancer: it may show lymph node enlargement, compression of trachea and esophagus, and in severe cases, lung metastasis. It can be treated by thyroxine, which inhibits the body from forming thyroid stimulating hormone, or one or both thyroid glands can be removed according to the condition of thyroid tumor. If the tumor has bone or lung metastasis, the thyroid gland should be removed and treated with iodine-131. 2. Medullary thyroid carcinoma: It is a moderate malignant tumor and usually occurs in the C-cell of thyroid gland. If lymph nodes in the cervical area are found to have metastasis before surgery, the lymph nodes in the cervical area should be cleared and thyroxine treatment can be given after surgery; 3. Follicular thyroid cancer: it can generally metastasize to liver, brain, bone and lung through bloodstream. It needs to be treated with iodine-131 after surgery to remove both sides of thyroid gland; 4. Undifferentiated thyroid cancer: it is common in elderly people, with higher malignancy and easily invades the surrounding blood vessels and nerves in the neck, which can be treated with radiotherapy and chemotherapy. Therefore, when thyroid level 4B is detected, there is a higher chance of malignant lesions, so close follow-up and review of thyroid ultrasound are needed to clarify the specific situation and then adopt appropriate treatment. If a thyroid tumor is diagnosed, the lesion should be controlled by surgical excision in a timely manner. In severe cases, radiotherapy and chemotherapy should also be used to control the patient’s condition.