Atypical chronic myeloid leukemias.

An ideal classification of the chronic myeloid leukemias would be based on a thorough understanding of the aetiology, pathogenesis, clinical and laboratory features, and natural history of the various conditions which comprise CML. Only in the case of CGL is the pathogenesis well understood and the diagnosis of the remaining disorders is still largely based on clinical and morphological criteria. It is inevitable for the reasons previously discussed that there will be cases which either defy classification or fall within the diagnostic criteria of more than one disorder. As long as careful clinical and morphological observation continues in parallel with advances in cellular and molecular biology it seems inevitable that the current debate about the inter-relationship between CMML, aCML and Philadelphia negative CGL will be resolved.