Myelofibrosis with myeloid metaplasia

Myelofibrosis with myeloid metaplasia (MMM) is a member of the chronic myeloproliferative disorder group as defined by the World Health Organisation. The disease is uncommon and is initially characterised by anaemia and cytopenia caused by the over-expression of growth factors released by malignant bone marrow megakaryocytes. Increased levels of several growth factors stimulate the production of collagenous proteins by bone marrow fibroblasts. Over time a leucoerythroblastic blood picture and teardrop poikilocytes are seen in the peripheral blood smear and progression to acute leukaemia is seen in some cases. MMM is difficult to treat, however, research into the mechanisms of fibroblast stimulation has led to a number of potentially useful drugs that may progress to clinical trials. Currently the treatment of MMM is palliative in most, with bone marrow transplant the only real curative option for selected patients.