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Bone Marrow Features in Masked Polycythemia Vera

Am J Hematol; 2017 Oct; Kvasnicka, Orazi, et al

Highly reproducible specific histological patterns characterize polycythemia vera (PV), according to an analysis involving 98 bone marrow specimens. Additionally, there do not appear to be substantial differences in bone marrow morphology between so-called masked/prodromal polycythemia vera (mPV) and overt PV.

6 hematopathologists evaluated histology slides in a blinded fashion. Specimens comprised cases of mPV (n=48); overt PV (n=31); and controls that included cases of JAK2-mutated essential thrombocythemia (ET), primary myelofibrosis, myelodysplastic syndrome, and various reactive conditions (n=19). Investigators looked for consensus in terms of differentiating mPV from ET. Among the results:

  • Overall, the interrater agreement rate was 93% with respect to separating mPV from ET.
  • Nearly all cases of mPV were correctly classified as PV.


Kvasnicka H, Orazi A, Thiele J, et al. European LeukemiaNet study on the reproducibility of bone marrow features in masked polycythemia vera and differentiation from essential thrombocythemia. Am J Hematol. 2017;92(10):1062-1067. doi:10.1002/ajh.24837.