Essential thrombocythemia developing into refractory anemia and complicated by acute myeloid leukemia

We report a case of essential thrombocythemia (ET) that climaxed in acute myeloid leukemia after developing into refractory anemia. The male patient had ET that was stable for 8 years on carboquone therapy. However, at the age of 72 years he developed an acute terminal illness that was characterized by severe pancytopenia, circulating myeloblasts, extensive bone marrow infiltration by myeloblasts, and an abnormal karyotype [46, XY, t(8q-; 20q+)]. He subsequently died of severe bilateral pneumonia and heart failure. This case suggests that ET may be similar to polycythemia vera; progression to leukemia is unusual except after chemotherapy. Therefore, treatment of patients with asymptomatic ET may not be advisable.