Preleukemia: The hematologie syndrome preceding acute leukemia

Abstract

The literature dealing with preleukemia has been reviewed and the data compared with the clinical findings in 34 patients in whom an ill defined hematologic syndrome antedated the development of acute leukemia. These data indicate that the clinical and laboratory manifestations of the early phases of leukemia are less heterogeneous than has been generally assumed. Symptoms and physical findings lack specificity. Cytopenias dominate the early phase of this myeloproliferative syndrome. Anisocytosis and poikilocytosis with oval macrocytes are especially prominent and often suggest vitamin B 12 or folate deficiency. Other noteworthy findings in the peripheral blood include monocytosis, nucleated red cells, immature granulocytes and/or monocytes, a Pelger-Huët-like anomaly and large bizarre platelets. Bone marrow is typically normo- or hypercellular with mild maturation defects in the erythrocytic or granulocytic compartments, qualitative changes in erythrocytic precursors, monocytosis or monocytoid features of granulocytic precursors, and abundant atypical megakaryocytes. Although the bone marrow is abnormal, the changes are minimal to modest, and clear-cut findings of leukemia are lacking. Because these deviations from normal are subtle, diagnostic equivocation ensues. After a variable period of time (usually within 3 to 24 months), this myeloproliferative disorder evolves into overt leukemia (most often involving two or more marrow cell lines) and terminates with an acute leukemia characterized by an over-abundance of blast cells with morphologic features of myeloblasts and/or monoblasts.