[Intractable Myasthenia Gravis Accompanied with Thymoma;Report of a Case].

A 46-year-old female visited a hospital due to pelvic inflammatory disease (PID) and then her chest computed tomography revealed an abnormal shadow in the upper mediastinum. Four months later,she complained muscle weakness with her limbs, dysphagia, and ptosis of her eyelids. Total thymectomy was performed through a median sternotomy for mass lesion, which was pathologically proven to be type B1 thymoma. Postoperative myasthenia gravis (MG) crisis, which led to respiratory failure requiring intubation and mechanical ventilation, developed and laboratory tests showed elevated serum anti-AChR Ab(130 nmol/l), antinuclear antibody( ×640 serum dilution, speckled pattern) and anti-RNP Ab(129.2 U/ml). For MG crisis, steroid pulse therapy, immunosuppressive therapy and immuno absorption were performed, and she successfully weaned from mechanical ventilaton on 41 post operative day (POD). Some factors such as inapparent mixed connective tissue disease (MCTD) and Anti RNP antibody were thought to be a cause for having any difficulty in MG treatment in the present case.