Acquired pure megakaryocytic aplasia report of two cases with long-term responses to antithymocyte globulin and cyclosporine.

Acquired pure megakaryocytic aplasia is a rare disorder defined by severe thrombocytopenia with no other hematologic abnormalities and absent, or severely decreased marrow megakaryocytes. The etiology may be immune suppression of megakaryocyte development. Two patients are described who both responded rapidly to a combination of antithymocyte globulin and cyclosporine and who remain in remission 13-20 months after discontinuation of cyclosporine. This regimen is well described for treatment of aplastic anemia and may also be effective for acquired pure megakaryocytic aplasia.