Acute myeloblastic leukaemia with marrow fibrosis (malignant myelosclerosis): acute leukaemia or malignant myelosclerosis?

Malignant myelosclerosis has been described as a rare form of acute myeloproliferative disorder characterised by minimal or absent splenomegaly, cytopenias, circulating myeloblasts and diffuse marrow fibrosis, but distinction between this entity and acute myeloblastic leukaemia with marrow fibrosis is difficult. This report describes a 50-year-old man who presented with features similar to those of malignant myelosclerosis but ther terminal stage was characterised by generalised lymphadenopathy, bone tenderness, marked leucocytosis and myeloblastaemia. Post mortem examination showed multiple chloromata consisting of myeloblasts. These findings suggest that malignant myelosclerosis may be but a variant of acute myeloblastic leukaemia and probably should be treated similarly. A possible association between diagnostic medical irradiation and this acute myeloproliferative disorder is discussed.