Thymic tumors 9 mm are microscopic tumors, if recent changes are obvious should be timely surgical treatment, if necessary, postoperative radiotherapy to prevent recurrence. Surgical resection is feasible, including thymectomy and resection of all lesions visible to the naked eye. If the patient is combined with myasthenia gravis, extended resection should be performed to ensure the removal of all possible thymic tissues or ectopic thymus. Bilateral phrenic nerve injury should be avoided and the presence of implants in the pleural cavity should be noted and removed if present. Radiation therapy is mainly used for the treatment of thymoma after palliative resection, which can reduce or prevent local recurrence of the tumor. At the same time, it can make the tumor shrink, facilitate resection and prevent pleural metastasis during operation. Chemotherapy is suitable for patients who cannot be operated or have recurrence after radiotherapy or after surgery. Common chemotherapeutic drugs include cisplatin, nitrogen mustard, methylbenzylhydrazine, prednisolone, vincristine, amyloxacin, cyclophosphamide and so on. To improve the efficacy, multi-agent combination chemotherapy regimens are generally used. If diagnosed with thymoma, you should seek medical treatment in time and under doctor’s guidance, do not use drugs without authorization, so as not to delay the condition. Pay attention to rest on weekdays, quit smoking and drinking, and keep regular work and rest.