Preleukemic states. I. Definition and classification. II. Refractory anemia with an excess of myeloblasts in the bone marrow (smoldering acute leukemia).

Approaches to the diagnosis and classification of preleukemic states involving chronic cytopenias are presented and discussed. Diagnosis of these states is facilitated by the identification of anomalies in all the myeloid cell lines (i.e., those derived from the bone marrow). These cellular anomalies may be morphologic, biochemical, or functional in nature or may affect the quantity of cell in each line in the bone marrow and the peripheral blood. Such anomalies may occur alone or may be associated. A tentative classifiction is proposed which is based on one or several of these anomalies. Among the quantitative criteria of classification is a moderate and static excess of myeloblasts and promyelocytes in the bone marrow. Refractory anemia with an excess of myeloblasts (RAEM) in the most frequent of these states. Its main clinical and hematologic features are described. The disease course is quite typical, the mean survival being 20 months; some patients survive for more than 30 months. Acute myeloid leukemia (AML) was the cause of death in less than 28% of cases. Infection in the absence of severe neutropenia was frequent. The relationship between RAEM and AML is disc,ssed, and the individual characteristics of RAEM are emphasized.