THE MYELOPROLIFERATIVE DISORDERS AN HISTORICAL APPRAISAL AND PERSONALEXPERIENCES

According to strict morphological, biochemical and cytogenetic criteri a Philadelphia chromosome positive essential thrombocythemia and chron ic granulocytic leukemia constitute a separate malignant and individua l disease entity, whereas Philadelphia chromosome negative essential t hrombocythemia, polycythemia vera and agnogenic or megakaryocytic myel oid metaplasia form a chronic proliferation of three hematopoietic cel l lines. Histopathology from bone marrow biopsies permits the characte rization and diagnostic differention of the various myeloproliferative disorders and appears to be a main and specific diagostic criterion f or polycythemia vera and essential thrombocythemia. Hemorrhagic thromb ocythemia is a clinical syndrome of recurrent spontaneous mucocutaneou s and secondary hemorrhages often preceded by thromboses, extremely hi gh platelet counts, pseudohyperkalemia, increased bone marrow cellular ity and frequently splenomegaly. The diagnostic criteria of essential thrombocythemia with paradoxical occurrence of thrombotic events and h emorrhagic manifestations are a platelet count in excess of 1000 x 10( 9)/L and increased bone marrow cellularity in the majority of the case s. Erythromelalgia and other microcirculatory ischemic or thrombotic e vents or accidents in essential thrombocythemia and polycythemia vera already occur at platelet counts in excess of the upper limit of norma l. First line treatment options in essential thrombocythemia and polyc ythemia vera are control of platelet function with low-dose aspirin an d reductive control of platelet count and erythrocytes by bloodletting , interferon and busulfan or hydroxyurea monochemotherapy.