Published online Aug 6, 2015. doi: 10.5315/wjh.v4.i3.16
Peer-review started: June 23, 2014
First decision: August 14, 2014
Revised: March 14, 2015
Accepted: April 28, 2015
Article in press: April 30, 2015
Published online: August 6, 2015
Core tip: The 2015 World Health Organization-Clinical Molecular and Pathological criteria define three phenotypes of JAK2V617F mutated myeloproliferative neoplasms (MPNs) essential thrombocythemia (ET), prodromal polycythemia vera (PV), prodromal PV, hypercellular megakaryocytic-granulocytic myeloproliferation and classical PV vs the JAK2 exon 12 mutated idiopathic eryhrocythemia and PV. MPL515 mutated JAK2 wild type ET and myelofibrosis is a distinct thrombocythemia without features of PV in blood and bone marrow. Calreticulin mutated JAK2/MPL wild type ET and myelofibrosis is the third thrombocythemia entity with characteristic features of primary megakaryocytic granulocytic myeloproliferation in the bone marrow, which are not seen in JAK2 and MPL mutated MPNs. MPN disease burden is best reflected by the degree of anemia and splenomegaly on top of mutation allele burden, bone marrow cellularity and increase of reticulin fibrosis.