Pure red cell aplasia and myasthenia gravis with recurrent thymoma.
In 1995, a 42-year-old male underwent thymothymectomy for thymoma (Masaoka stage Ⅲ) followed by 50-Gy irradiation to the mediastinum. One year after the operation, the patient was diagnosed with post-thymectomy myasthenia gravis (MG). The thymoma recurred in this patient, and he underwent tumor extirpation for recurrent thymomas in 2001 and 2006. He also underwent adjuvant chemotherapy after the operation in 2006. Approximately two months after the last administration of anticancer drugs, the patient presented with shortness of breath on effort and palpitation, and consulted at our hospital outpatient clinic. His hemoglobin concentration was 6.2 g/dl, and his reticulocyte count was 0.1%. His white blood cell and platelet levels were, however, within normal range. A bone marrow biopsy revealed severe erythroid hypoplasia with normal myeloid and megakaryocytic lineage. Based on these findings, pure red cell aplasia (PRCA) was diagnosed. Oral administration of cyclosporin A (350 mg/day (5 mg/kg)) was started after a final diagnosis. Six months after the initiation of treatment with this immunosuppressant drug, the patient required no additional transfusion with a normal hemoglobin concentration.