 Myasthenia gravis MG is an autoimmune disease involving the thymus in which 85 percent of patients have antibodies to muscle acetylcholine receptors AchR-Ab that interfere with neuromuscular transmission. MG frequently causes severe disability that can be life-threatening. Thymectomya surgical procedure that removes thymus gland tissue from the chest cavityhas been an established therapy for non-thymomatous MG, or MG without thymoma, for more than 60 years based on retrospective, non-randomized studies. Corticosteroids are now being used increasingly either as the sole treatment or in combination with thymectomy. Both therapies have associated adverse effects and indications for their use based on randomized trial data are lacking. 