Malignant thymoma complicated by amegakaryocytic thrombocytopenic purpura.

We report the case of a 41-year-old man with malignant thymoma complicated by amegakaryocytic thrombocytopenia 10 years after diagnosis of myasthenia gravis. A bone marrow aspirate showed an absence of megakaryocytes with normal maturation and differentiation of myeloid precursors. Three months later, severe neutropenia occurred, and a bone marrow examination confirmed the diagnosis of severe aplastic anemia. Associations between thymoma and myasthenia gravis, between thymoma and pure red cell aplasia, and between thymoma and aplastic anemia are well documented. Amegakaryocytic thrombocytopenia is not a recognized paraneoplastic syndrome complicating thymoma. Amegakaryocytic thrombocytopenia complicating thymoma may be a very early presentation of impending aplastic anemia.