The thymus gland is an immune organ of the body, and as we age, thymic tissue gradually degenerates, especially after the age of 20, when it basically disappears. Therefore, close observation and conservative treatment are adopted for thymic hyperplasia found before the age of 20, but aggressive surgical treatment is required for thymic hyperplasia found after the age of 20. There are different surgical methods for thymus surgery, and the surgical method mainly depends on the size of the thymus. If the thymus is relatively large and closely related to the surrounding blood vessels, it may be removed by median open-heart surgery; if the thymus tissue is relatively small, usually nowadays expanded thymectomy under thoracoscopy is used, which is the main surgical method for thymus treatment.