Does a Diagnosis of Myelogenous Leukemia Require 20% Marrow Myeloblasts, and Does <5% Marrow Myeloblasts Represent a Remission? The History and Ambiguity of Arbitrary Diagnostic Boundaries in the Understanding of Myelodysplasia

This commentary discusses the current use of arbitrary boundaries to distinguish the continuum of incipient (clonal cytopenias), oligoblastic (subacute), and polyblastic (acute) myelogenous leukemia. The historical path that led to the application of these boundaries is discussed, and simplification of the current diagnostic classification is proposed.