Polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) are currently classified as BCR-ABL-negative classic myeloproliferative neoplasms (MPN). According to the revised 2008 World Health Organization (WHO) classification system, adult chronic myeloid neoplasms are now divided into four broad categories; myelodysplastic syndrome (MDS), MPN, "MDS/MPN overlap" and "myeloid or lymphoid neoplasms associated with eosinophilia and abnormalities of PDGFRA, PDGFRB or FGFR1" . The WHO MPN category includes the four classic MPN: chronic myelogenous leukemia (CML; BCR-ABL-positive), PV, ET, and PMF. All three BCR-ABL-negative MPN are uncommon and incidence figures are estimated at 0.2-2.5/100,000 for ET [2-4], 0.4 to 1.5/100,000 for PMF [2, 3] and 0.8-2.6/100,000 for PV [5, 6]. The median age at diagnosis for all these three MPN is approximately 60∈years .