The thymus gland is located in the anterior mediastinum of the thoracic cavity behind the sternum and is an important lymphatic organ in the human body, whose function is closely related to immunity. In the late embryonic stage and at birth, the human thymus weighs about 10-15 g. As we grow older, the thymus gland continues to develop to about 30-40 g in adolescence, and the thymus gland assumes an important responsibility in the development of the human immune system. After adulthood the thymus gradually degenerates, lymphocytes decrease and adipose tissue increases to only 15 grams in old age. If the thymus continues to proliferate or grows into a thymoma after adulthood, it will easily lead to the occurrence of myasthenia gravis. According to incomplete clinical statistics, 90% of patients with myasthenia gravis have thymus abnormalities, about 70% of patients have thymic hyperplasia, and 10-15% of patients have thymoma. The significant improvement in symptoms and the significant decrease in AChR antibody titers in some patients after thymectomy suggest that the thymus is associated with myasthenia gravis. However, it is important to note that not all patients require thymectomy for myasthenia gravis, and we recommend it for patients over 18 years of age with systemic thymic hyperplasia who have had poor results and thymomas, and for children with myasthenia gravis who require caution in removing the thymus. For adults with myasthenia gravis detected for the first time, it is better to remove the thymus gland sooner rather than later, so please consult your doctor for details.