Pure RBC aplasia and myasthenia gravis. Coexistence of two diseases associated with thymoma.

Pure RBC aplasia (PRCA) and myasthenia gravis (MG) are occasionally associated with thymoma, although the occurrence of all three in a single patient is rare. We describe a patient in whom PRCA and MG occurred in conjunction with the presence of serum autoantibodies, evidence for a serum inhibitor of erythropoiesis, and elevation of circulating thymosin alpha 1. Although a thymoma could not be detected before death, postmortem examination of the mediastinum found scattered cells within a nodule, suggestive of a lymphoepithelial thymic neoplasm.