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

摘要

This commentary discusses the current use of arbitrary boundaries to distinguish the continuum of the clonal cytope-nias and oligoblastic (subacute) and polyblastic (acute) my-elogenous leukemia. Each is the result of the neoplastic transformation of a primitive multipotential hematopoietic cell and, in many cases, the result of clonal evolution to a more rapidly progressive myeloid neoplasm. This paper examines the historical path that led to the application of these boundaries and cites several recent studies showingthat the boundaries in current use are not based on pathobiological findings and are arbitrary. Simplification of the current diagnostic classification of the (a) incipient (clonal cytopenias), (b) oligoblastic, and (c) polyblastic myelogenous leukemias is proposed. These classifications may be more consistent with general concepts of the diagnostic designations of neoplastic diseases as well as less idiosyncratic and more understandable for bio-medical scientists, health care students and trainees, demographers, epidemiologists, hematological oncologists and pathologists, patients, science journalists, and other interested lay parties.