Idiopathic myelofibrosis: historical review, diagnosis and management.

Idiopathic myelofibrosis is reviewed from several aspects. The historical development of knowledge about this disorder is discussed, from early descriptions of extramedullary hematopoiesis associated with numerous etiologies, a debate over pathogenetic mechanisms, followed by newer evidence which placed this disorder with the myeloproliferative disorders. Evidence is presented showing that idiopathic myelofibrosis is an acquired clonal disorder in terms of the hematopoietic abnormalities, but that the marrow fibrosis is a result of non-clonal disordered fibrogenesis. The clinical, laboratory and pathologic features of idiopathic myelofibrosis are discussed. The features which distinguish this disorder from the other myeloproliferative disorders, particularly chronic myelogenous leukemia are emphasized. The natural history is described together with an evaluation of accepted and experimental therapy.