SURGERY IN MYASTHENIA GRAVIS

Abstract

The indications of thymectomy in myasthenia gravis (MG), the variant surgical accesses and techniques, as well as the oncological principles of thymoma resection are thoroughly discussed. Main indications of thymectomy in MG are 1. Positive acetylcholine receptors antibodies in non-thymomatous patients younger than 50-60 years with moderate or severe weakness and 2. Thymoma presence. The operative approaches are based either on sternotomy or on thoracoscopy in various versions concerning to the planning, the extent, and the completeness of the resection. The purpose of the operation remains the radical resection of the whole thymic gland with aberrant foci. The prognosis of MG after thymectomy in non-thymomatous MG is better than in the thymomatous one, whereas thymomatous MG is more frequent in histological types B2 and B3 (according to WHO classification). The main determinant in thymoma prognosis is completeness of resection, whereas Masaoka stage and WHO histological type are related with disease free survival as significant prognostic factors. Magnetic resonance imaging and positron emission tomography (PET-CT) contribute essentially in differential diagnosis of hyperplastic thymus from thymoma (MRI), as well as of thymoma from thymic carcinoma (PET-CT).