Elliptocytosis preceding myelofibrosis in a patient with polycythemia vera

A patient with polycythemia vera showed marked elliptocytosis in the peripheral blood, 2 years after the diagnosis was established. 4 years later on, the patient developed myelofibrosis. The significance of elliptocytosis, which appears during the course of polycythemia vera, as an early indicator for the development of myelofibrosis is discussed.