Thyroid nodule category 4a, or TI-RADS category 4a. Follow-up is an option for smaller, unifocal nodules that are not immediately adjacent to the peritoneum, trachea, or recurrent laryngeal nerve; in other cases, it is recommended that a puncture biopsy be performed first, which shows malignancy and requires consideration of surgical treatment, while benign cases do not require surgery; surgery may also be indicated if the nodule is too large to cause compression symptoms or cosmetic problems. According to the thyroid TI-RADS classification, category 4a is a low suspected malignant nodule with a 2% to 10% risk of malignancy. If the nodule is a smaller, unifocal nodule that is not in close proximity to the peritoneum, trachea, or recurrent laryngeal nerve, follow-up may be an option and surgery may not be necessary for the time being. If the nodule is large or multifocal, or in the immediate vicinity of the peritoneum, trachea, or recurrent laryngeal nerve, a puncture biopsy is recommended. If the biopsy results show malignancy, timely surgical resection is recommended, while benign nodules can be treated without surgery for the time being, with regular follow-up. Benign nodules can also be surgically removed if they become too large and cause pressure or cosmetic problems. Patients diagnosed with thyroid nodule category 4a should be treated under the guidance of a doctor, who should formulate a treatment plan taking into account the specific situation.