title: Myelofibrotic transformations of polycythemia vera and essential thrombocythemia are morphologically, biologically, and prognostically indistinguishable from primary myelofibrosis.
abstract: A fraction of polycythemia vera (PV) and essential thrombocythemia (ET) cases will, in time, undergo myelofibrotic transformation. In such cases, fibrosis may mask the diagnostic histologic features of the original underlying myeloproliferative neoplasm. Thus, confidently differentiating postfibrotic PV/ET from primary myelofibrosis (PMF) histologically may not be possible. It is controversial whether post-PV/ET myelofibrosis (MF) differs clinicopathologically from PMF, or whether these entities are biologically, clinically, and prognostically indistinguishable. To answer this question, we compared multiple candidate biological, morphologic, and prognostic parameters between 19 postfibrotic ET/PV individuals and 18 PMF individuals. The postfibrotic ET/PV and PMF cases did not differ with regard to clinical outcome, cytogenetic abnormalities, serum lactate dehydrogenase level, peripheral blast count, bone marrow morphology, or grade of reticulin fibrosis. Only JAK2 allele burden, which was higher in the postfibrotic PV/ET population (P=0.011), differed between the 2 groups. Cardinal morphologic features of PMF (ie, marrow cellularity, intrasinusoidal hematopoiesis, osteosclerosis, etc.) were commonly observed in post-PV/ET MF marrow biopsies, and only a minority of post-PV/ET MF marrow biopsies the retained diagnostic features of the primary myeloproliferative neoplasm (panmyelosis in PV and megakaryocytic hyperplasia in ET). Our study indicates that PMF and post-PV/ET MF are clinically and biologically indistinguishable.
authors.affiliation: Departments of *Pathology ‡Hematology, University of Utah Health Sciences Center †ARUP Institute of Clinical and Experimental Pathology, Salt Lake City, UT.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Sangle
authors.forename: Josh
authors.initials: J
authors.lastname: Cook
authors.forename: Sherrie
authors.initials: S
authors.lastname: Perkins
authors.forename: Carolin J
authors.initials: CJ
authors.lastname: Teman
authors.forename: David
authors.initials: D
authors.lastname: Bahler
authors.forename: Kimberly
authors.initials: K
authors.lastname: Hickman
authors.forename: Andrew
authors.initials: A
authors.lastname: Wilson
authors.forename: Josef
authors.initials: J
authors.lastname: Prchal
authors.forename: Mohamed E
authors.initials: ME
authors.lastname: Salama
mesh_terms: D000483:Alleles; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D008297:Male; D008533:Megakaryocytes / Q000378:metabolism / Q000473:pathology; D011087:Polycythemia Vera / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D055728:Primary Myelofibrosis / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D013920:Thrombocythemia, Essential / Q000235:genetics / Q000378:metabolism / Q000473:pathology
chemical_list: D007770:L-Lactate Dehydrogenase; C507924:JAK2 protein, human; D053614:Janus Kinase 2