“Thyroid nodule 4c” generally refers to a thyroid nodule that is classified as category 4C on ultrasound. Thyroid nodules in category 4C may be benign, but they may also be malignant. Category 4C nodules are highly suspicious for malignancy and have a 50% to 90% malignancy rate. If a category 4C nodule is >10mm, puncture is recommended; if the nodule is adjacent to the perineurium, trachea, or laryngeal reentrant nerve, or if the nodule is multifocal, then puncture may be considered at >5mm. Thyroid nodule puncture is a relatively common clinical diagnosis of thyroid disease, according to the results of the puncture examination, the physician can diagnose the nature of the thyroid nodule, if the nodule is benign, regular review can be; if the nodule is malignant, can be considered through surgery and other means of treatment. Patients diagnosed with category 4C thyroid nodules who want to clarify the nature of the nodules can go to the hospital and under the guidance of the doctor for examination and treatment.