Thanks for your question. Patients with myasthenia are able to have surgery, but the drugs must be appropriately tailored. Removal of the thymus was classically performed for the treatment of Myasthenia. The question really is, are these elective surgeries worth the risk?
As a board certified plastic surgeon I would need to communicate with your internist for more information and then speak to our anesthesia staff. Your PS will likely want to do the same. With further information you will be able to make an informed decision.