Diagnosis and treatment of the preleukemic syndrome (hemopoietic dysplasia).

Retrospective and prospective observations have established the existence of a recognizable hematologic syndrome preceding the development of acute nonlymphocytic leukemia. This syndrome, which has been termed the "preleukemic syndrome" or "hemopoietic dysplasia", appears to be a stage in a multiphasic myeloproliferative disorder, rather than a separable disease with a propensity to develop leukemia. All products of the marrow stem cell are involved. The panmyelopathy begins as a red cell disease (eg, a refractory or sideroblastic anemia) and progresses to involve megakaryocytes and platelets and finally granulocytes or monocytes, or both; the terminal event is acute nonlymphocytic (myelomonoblastic) leukemia. Prospective documentation is needed in order to define the natural course of this marrow disease. Such studies are now in progress and should provide important information concerning the pathophysiology of acute nonlymphocytic leukemia.