Thrombotic thrombocytopenic purpura accompanied by transient pure red cell aplasia and thymoma

We describe a 64-year-old man with thrombotic thrombocytopenic purpura (TTP), transient pure red cell aplasia (PRCA) and thymoma. TTP in this case was thought to be idiopathic and was accompanied by microangiopathic hemolytic anemia. The patient, therefore, had an aplastic crisis due to PRCA. He was treated with peritoneal dialysis, plasma exchange with plasma infusion, red blood cell transfusion, methylprednisolone pulse therapy followed by maintenance dosing with intravenous prednisolone, gamma-globulin, vincristine, and dipyridamol. As a result, the patient's mental disorder, acute renal failure, anemia and thrombocytopenia improved; however, the haptoglobin level remained low. The pathogenesis of PRCA and thymoma indicates that these are immunological disorders often associated with each other. To our knowledge, there are no reports of TTP with transient PRCA and thymoma. Although such a combination is considered relatively rare, this case suggests that there is an immunological contribution to the pathogenesis of the association of these disorders.