Pure Red Cell Aplasia in a Patient with Thymic Hyperplasia, Hypogammaglobulinemia and Adult T-cell Leukemia/Lymphoma

Acquired pure red cell aplasia (PRCA), caused by thymic hyperplasia, is extremely rare. We herein report a previously healthy 41-year-old man who presented with severe anemia, lymphadenopathy, an upper mediastinal mass, and hypogammaglobulinemia. The patient was eventually diagnosed with PRCA and adult T-cell leukemia/lymphoma (ATLL). The mediastinal mass was pathologically diagnosed as thymic hyperplasia without clear ATLL invasion. Although his anemia improved rapidly after thymectomy, PRCA recurred approximately 500 days later and was accompanied by ATLL exacerbation. The findings in this patient suggest that the Good's syndrome-like symptoms (thymic hyperplasia and hypogammaglobulinemia) in this patient and PRCA may have been paraneoplastic syndromes caused by ATLL.