Whether a thymic nodule of 7.4 mm is serious or not depends mainly on the nature of the patient’s thymic nodule and the clinical symptoms caused by the thymic nodule. If the thymic nodule is a benign lesion and the patient has no clinical symptoms, this condition is not serious, and if the thymic nodule is a malignant lesion with obvious symptoms, this condition is serious. Thymic nodule 7.4 mm, if benign lesions, the patient does not have clinical symptoms, this case, not serious, and does not require special treatment, regular review can be, usually 3 to 6 months to review the chest CT or ultrasound can be, to understand the size of the thymic nodule changes. If it is found that thymic nodule becomes bigger, compresses or invades the surrounding tissues, and there is chest tightness, shortness of breath, etc., it is considered to be thymoma or thymic carcinoma, which is more serious and should be treated by surgical resection as early as possible. Patients with thymic nodules are advised to go to the hospital in time and avoid carelessness so as not to delay the treatment.