Myasthenia gravis(MG)is an antibody mediated, T cell dependent autoimmune disease characterized by a disorderof neuromuscular junction with progressive inability to sustain a maintained or repeated contraction of striated muscle. It is represented by antibodies directed against the nicotinic acetylcholine receptors (nAchR) of the post junctional membranes. We present the case of an 82-year-old patient, who was admitted to the hospital for plasmapheresis due to an aggravation of her auto-immune generalized myasthenia. The clinical examination at admission revealed ptosis, dysphagia, a medium effort dyspnea, difficulties in closing the mouth, dysphonia with a nasal voice and limited walking with a bent head and camptocormia, with Osserman score 46/100 (diplopia and bilateral ptosis). The thoracic scanner describes a tissue lesion in the thymus region with a diameter of 35 mm corresponding to a thymoma. The Magnetic Resonance Imaging confirmed the possible thymoma. A thymectomy using video-assisted thoracoscopic surgery (VATS) technique was performed according to the age and general status of the patient. Post-operative histological examination revealed a B2 type thymoma and the TNM staging system classifies the thymoma as being T1bNx.