Thrombocytopenia with decreased megakaryocytes. Evaluation and prognosis.

The presenting clinical pictures and courses of seven patients with thrombocytopenia, decreased megakaryocytes in the marrow, and minimal changes in other hematopoietic cell lines are described. Little information exists in the literature on such patients. Initial bone marrow aspiration and biopsy in all patients showed decreased megakaryocytes with an otherwise normal marrow. Erythrocyte mean corpuscular volume was elevated in five of seven patients. Bone marrow karyotypes of six of the seven patients were normal. Chromium-51 platelet survival studies with platelet sizing, done in five of the seven patients, showed normal results. In two patients the course progressed to aplastic anemia. One of these died 9 months after presentation, and one responded dramatically to lithium. One patient developed preleukemia and died. The other four patients have remained thrombocytopenic but clinically stable. No useful therapy was identified. The differential diagnosis of such patients should include idiopathic thrombocytopenic purpura with misinterpretation of morphologic findings, hereditary and acquired aplastic anemia, preleukemia, and systemic lupus erythematosus.