Cerebral venous thrombosis and myeloproliferative neoplasms: Results from two large databases

Introduction: Myeloproliferative neoplasms (MPNs) include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Patients with MPNs are prone to develop arterial and venous thrombosis either at diagnosis or during follow- up; in particular splancnic vein is strongly associated with MPN. Conversely, presence of MPN is uncommon in patients with deep vein thrombosis of the lower extremities and with pulmonary embolism. Only few studies with conflicting results have evaluated the prevalence of an underlying MPN in patients with cerebral venous thrombosis (CVT), and limited evidence exists on the incidence of CVT in patients with established MPN. Methods: We assessed the frequency of MPNs in a series of 706 patients with cerebral vein thrombosis (CVT) and the frequency of CVT in a cohort of 2,143 MPNs patients. Results: Twenty- seven CVT patients (3.8%) were diagnosed with MPN: 9 before CVT (1.3%), 4 concomitantly (0.6%), and 14 after CVT (2.0%). Nine CVT cases (0.4%) were diagnosed in the MPN cohort, with a slightly higher frequency in PV (five of 735, 0.7%) than in ET (three of 964, 0.3%) and in PMF (one of 444, 0.2%). Conclusion: Considering the analyses of these databases jointly, the results obtained suggest a weak association between CVT and MPNs and ultimately suggest that a thorough investigation looking for an underlying MPN may not be warranted in all the patients with CVT without overt myeloproliferative features. (C) 2014 Elsevier Ltd. All rights reserved.