Myeloproliferative neoplasm classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Mohamad Alkateb, MBBCh [2], Shyam Patel [3]

Overview

Myeloproliferative neoplasm may be classified according to the World Health Organization into eight subtypes: polycythemia vera, essential thrombocythemia, primary myelofibrosis, chronic myelogenous leukemia, chronic neutrophilic leukemia, chronic eosinophilic leukemia, myeloproliferative neoplasms unclassifiable, and mastocytosis. Each subtypes is based on a distinct malignant cell, and each subtype has different criteria for diagnosis.

Classification

Myeloproliferative neoplasm may be classified according to the World Health Organization into eight subtypes as follows:^[1]^[2]^[3]

Disease	Cell of origin	W.H.O. Diagnostic criteria
Polycythemia vera	Erythroid precursor	Major criteria: Hemoglobin > 16.5 g/dl in men or hemoglobin > 16 g/dl in women Bone marrow biopsy showing hypercellularity for age and trilineage growth (panmyelosis) Presence of JAK2 V617F or exon 12 mutation Minor criterion: Subnormal erythropoietin level Diagnosis requires meeting all 3 major criterion or the top 2 major plus the 1 minor criterion
Essential thrombocythemia	Megakaryocyte	Major criteria: Platelet count > 450,000 per microliter Bone marrow biopsy showing mainly the proliferation of megakaryocytes with an increased number of enlarged and mature megakaryocytes Not meeting criteria for other myeloproliferative neoplasms Presence of JAK2, CALR, or MPL mutation Minor criterion: Presence of a clonal marker or absence of reactive thrombocytosis Diagnosis requires meeting all 4 major criteria or the first 3 major plus the 1 minor criterion
Primary myelofibrosis	Megakaryocyte	Major criteria: Presence of megakaryocyte proliferation and atypia with reticulin fibrosis Not meeting criteria for other myeloproliferative neoplasms Presence of JAK2, CALR, or MPL mutation Minor criteria: Anemia White blood cell count >11,000 per microliter Palpable splenomegaly Elevated LDH Leukoerythroblastic smear Diagnosis requires meeting all major criteria and at least 1 minor criterion
Chronic myeloid leukemia	Common myeloid progenitor	Presence of BCR-ABL translocation (chromosomes 9 and 22)
Chronic neutrophilic leukemia	Neutrophil	Peripheral blood white blood cell count > 25,000 per microliter with rare myeloblasts and no dysgranulopoiesis Bone marrow hypercellularity with increased granulocytes and normal maturation and <5% myeloblasts Not meeting criteria for other myeloproliferative neoplasms Absence of genetic rearrangements of PDGFRA, PDGFRB, FGFR1, or PCM1-JAK2 Presence of CSF3R T618I or other characteristic mutation
Chronic eosinophilic leukemia	Eosinophil	No formal W.H.O. criteria Typically associated with >1,500 eosinophils per microliter in peripheral blood Typically associated with rearrangements of PDGFRA, PDGFRB, FGFR1, JAK2
Myeloproliferative neoplasm, unclassifiable	Variable	Not meeting criteria for other subcategories
Mastocytosis	Mast cell	Major criteria: Dense multifocal aggregates of >15 mast cells in bone marrow or other organs Minor criteria: Presence of C-kit D816V mutation Expression of CD2, CD25, or both on mast cells Serum tryptase level >20ng/ml when a patient is at baseline health Atypical morphology or spindles in >25% of mast cells in bone marrow or other organs Diagnosis requires meeting the one major plus one minor criterion, or 3 minor criteria

References

↑ Arber DA, Orazi A, Hasserjian R, Thiele J, Borowitz MJ, Le Beau MM; et al. (2016). “The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia”. Blood. 127 (20): 2391–405. doi:10.1182/blood-2016-03-643544. PMID 27069254.
↑ Vardiman JW, Thiele J, Arber DA, Brunning RD, Borowitz MJ, Porwit A; et al. (2009). “The 2008 revision of the World Health Organization (WHO) classification of myeloid neoplasms and acute leukemia: rationale and important changes”. Blood. 114 (5): 937–51. doi:10.1182/blood-2009-03-209262. PMID 19357394.
↑ Valent P, Akin C, Hartmann K, Nilsson G, Reiter A, Hermine O; et al. (2017). “Advances in the Classification and Treatment of Mastocytosis: Current Status and Outlook toward the Future”. Cancer Res. 77 (6): 1261–1270. doi:10.1158/0008-5472.CAN-16-2234. PMC 5354959. PMID 28254862.

[pmid27069254-1] Arber DA, Orazi A, Hasserjian R, Thiele J, Borowitz MJ, Le Beau MM; et al. (2016). “The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia”. Blood. 127 (20): 2391–405. doi:10.1182/blood-2016-03-643544. PMID 27069254.

[pmid19357394-2] Vardiman JW, Thiele J, Arber DA, Brunning RD, Borowitz MJ, Porwit A; et al. (2009). “The 2008 revision of the World Health Organization (WHO) classification of myeloid neoplasms and acute leukemia: rationale and important changes”. Blood. 114 (5): 937–51. doi:10.1182/blood-2009-03-209262. PMID 19357394.

[pmid28254862-3] Valent P, Akin C, Hartmann K, Nilsson G, Reiter A, Hermine O; et al. (2017). “Advances in the Classification and Treatment of Mastocytosis: Current Status and Outlook toward the Future”. Cancer Res. 77 (6): 1261–1270. doi:10.1158/0008-5472.CAN-16-2234. PMC 5354959. PMID 28254862.

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Myeloproliferative neoplasm classification

Overview

Classification

References

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