The Importance of Searching for Acquired von Willebrand Syndrome in Chronic Myeloproliferative Neoplasms

Acquired von Willebrand syndrome is an entity unknown and misdiagnosed in most cases. It is a bleeding disorder presented with mild to moderate hemorrhagic symptoms secondary to lymphoproliferative disorders (and known as the most frequent cause of acquired von Willebrand syndrome), cardiovascular disease, myeloproliferative neoplasms (essential thrombocythemia, polycythemia vera, and chronic myeloid leukemia), autoimmune disease or solid neoplasms. The most known mechanisms of a von Willebrand antigen diminished consist of an increased degradation or clearance of circulating VWF. This occurs due to an increased plasma clearance of von Willebrand factor (VWF) caused by antibodies, cell adsorption, shear stress, or increased proteolysis induced by ADAMTS 13. Diagnosis is made by clinical assessment supplemented by laboratory tests of complete blood count (CBC), PT, aPTT with a VWF antigen, VWF:RCo, high molecular weight (HMW) multimer), and FVIII activity with findings in most cases the ratio of VWF:RCo to VWF:Ag usually diminished (<0.7) with a loss of HMW multimers. Management includes the selection of the best treatment for acute bleeding and treating the underlying condition Acquired von Willebrand syndrome is a pathology that should be investigated in chronic myeloproliferative neoplasms when platelet counts approach one million and the increase in hematocrit is significant, as it predisposes to bleeding.