“Thyroid 4a” generally refers to thyroid category 4A nodules, which are categorized under thyroid ultrasound and generally do not resolve spontaneously. Thyroid category 4A nodules have some possibility of malignancy and are of low suspected malignancy, with a 2% to 10% malignancy rate. Thyroid nodules are lesions caused by abnormal localized growth of thyroid cells and can be classified as benign or malignant. For patients with thyroid category 4A nodules, a puncture biopsy can be performed if necessary to clarify the nature of the nodule. If the thyroid 4A nodule is benign and asymptomatic, it can be followed up regularly for observation; if the nodule develops pressure symptoms such as dyspnea, dysphagia, or has a tendency to malignancy, it can be treated with surgery. Patients diagnosed with thyroid category 4A nodules should be treated under the guidance of a doctor.