EXTREME THROMBOCYTOSIS IN CHRONIC MYELOID LEUKEMIA IN THE ERA OF TYROSINE KINASE INHIBITORS

Thrombocytosis is a common feature in chronic myeloproliferative diseases and contributes to an increased incidence of thrombotic and haemorrhagic events during the course of the disease. In chronic myeloid leukemia (CML) however, haemorrhagic and thrombotic complications even with marked thrombocytosis are rare (3% and 1% respectively)[1]. The incidence of thrombocytosis in CML is reported to be around 30 to 50%. Extreme thrombocytosis defined as a platelet count > 1.000 x 109/l is uncommon in CML as well as isolated thrombocytosis and, as reported for other chronic myeloproliferative diseases, acquired von Willebrand syndrome (avWs) might occur [2]