Thyroid nodules category 4b 0.4 cm are at risk of malignancy and are recommended to be treated with either puncture or surgery under doctor’s evaluation. The TI-RADS (Thyroid Imaging Reporting and Data System) classification of thyroid nodules is based on ultrasound and other imaging results to assess the benignity of the nodule, category 4b nodules indicate suspected malignancy, with a probability of malignancy of 10-50%, and it is generally recommended to perform a thyroid puncture biopsy to clarify benignity and malignancy. If the puncture result of category 4b thyroid nodule suggests benign, it can be followed up regularly. If the nodule is malignant, surgery is required. It is recommended that the patient consider the other descriptions in the report and other clinical data, and follow the doctor’s instructions for examination and treatment.