Myasthenic crisis caused by preoperative chemotherapy with steroid for advanced thymoma.

We report the case of a 44-year-old woman with Masaoka stage IV, World Health Organization type B1 thymoma associated with pure red cell aplasia, thrombocytopenia, and myasthenia gravis, which occurred during preoperative chemotherapy with high-dose methylprednisolone. Noninvasive positive-pressure ventilation, intravenous immunoglobulin infusion, and methylprednisolone pulse therapy were performed for the myasthenic crisis. Disseminated thymoma was markedly reduced after these treatments, and macroscopic complete resection was performed after achieving control of pure red cell aplasia, myasthenia gravis, and thrombocytopenia using cyclosporine A. Chemotherapy, including high-dose methylprednisolone, may carry a risk of myasthenic crisis, although the regimen is effective against lymphocyte-rich thymoma.