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World J Hematol. Aug 6, 2013; 2(3): 71-88
Published online Aug 6, 2013. doi: 10.5315/wjh.v2.i3.71
Published online Aug 6, 2013. doi: 10.5315/wjh.v2.i3.71
Table 2 2008 World Health Organization and European Clinical, Molecular and Pathological criteria for the diagnosis and classification of JAK2V617F mutated essential thrombocythemia into 3 stags or phenotypes: important to differentiate because natural history differs
Clinical and molecular criteria | WHO bone marrow criteria |
ET stage 1 | Normocellular ET |
Platelet count of > 350 × 109/L and the presence of large platelets in a blood smear in all stages of ET | Predominant proliferation of enlarged megakaryocytes with hyperlobulated nuclei and mature cytoplasm, lacking conspicuous morphological abnormalities. No increase, proliferation or immaturity of granulopoiesis or erythropoiesis |
Presence of JAK2V617F mutation | No progression to post-ET myelofibrosis |
ET stage 2 | Prodromal PV |
Platelet count of ≥ 350 × 109/L and normal hematocrit: male < 51%, female < 48% | Increased cellularity with trilineage myeloproliferation (i.e., panmyelosis). Proliferation and clustering of small to giant (pleomorphic) megakaryocytes |
erythrocytes < 6 × 1012/L | No pronounced inflammatory reaction (plasmacytosis, cellular debris). Absence bone marrow features consistent with congenital polycythemia and secondary erythrocytosis |
Presence of JAK2V617F mutation | Progression to overt PV during follow-up |
Low serum EPO level and/or increased score for leukocyte alkaline phosphatase | |
Spontaneous EEC | |
ET stage 3 | ET.MGM |
Platelet count of ≥ 3500 × 109/L and no signs of leuko- erythroblastosis | Increased cellularity due to MGM and normal or relative reduction of erythroid precursors with various degrees pleiomorphic loosely clustered megakaryocytes containing dysmorphic (not cloud-like) nuclei and maturation defects |
Erythrocytes < 6 × 1012/L | No or slight RF (RF 0 or 1) |
Presence of JAK2V617F mutation | Progression to post ET myelofibrosis |
Slight splenomegaly on ultrasound and no anemia Hb > 12 g/dL | |
No preceding or allied of CML, PV, RARS-T or MDS |
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Citation: Michiels JJ, Berneman Z, Schroyens W, Lam KH, De Raeve H. PVSG and WHO
vs European Clinical, Molecular and Pathological Criteria for prefibrotic myeloproliferative neoplasms. World J Hematol 2013; 2(3): 71-88 - URL: https://www.wjgnet.com/2218-6204/full/v2/i3/71.htm
- DOI: https://dx.doi.org/10.5315/wjh.v2.i3.71