In the evaluation of a 64-year-old woman with fluctuating neurological signs of ptosis, eleventh and twelfth cranial nerve palsy, and generalized extremity weakness are noted. Edrophonium (Tensilon) given intravenously results in clinical improvement. A computed tomography (CT) scan shows a lesion in the anterior mediastinum, and a biopsy confirms the presence of a thymoma. She should undergo which of the following?

The role of thymectomy in treating patients with myasthenia gravis who have a thymoma is well established. The thymus gland is located in the anterior mediastinum and can be approached by a cervical or mediastinal approach. It arises from the third and fourth branchial arches. Thymectomy is frequently advised for patients with myasthenia gravis who do not have a thymoma; however, there are some authorities who would treat these patients initially with an anticholinesterase drug such as pyridostigmine (Mestinon). Corticosteroid therapy may be indicated when thymectomy has failed, but it must be undertaken cautiously, because the drug may precipitate severe weakness. Pneumococcal infections (which may occur after splenectomy performed in children) are not a specific complication noted after thymectomy.