[Preleukemic states]

The preleukemic states are disorders which constitute early phases of acute non-lymphoblastic leukemia. The nomenclature associated with the preleukemias has been confusing, and therefore the problems of their definition and diagnosis are discussed. The laboratory investigations are reviewed and the contribution of cytogenetic and cell cultures to improved knowledge of the pathophysiology is stressed. The preleukemic states are clonal hematopoietic stem cell malignancies manifested by maturation and proliferation defects of the different cellular strains of the marrow. Treatment of preleukemias remains controversial. While the use of cytostatic drugs is not generally accepted, remissions are reported to have been achieved by polychemotherapy. Chemotherapy in patients with severe complications of cytopenias thus appears to be justified. On the other hand, controlled studies of therapy in preleukemic states are needed.