Overview of Myelodysplastic/Myeloproliferative Neoplasms



Overview of Myelodysplastic/Myeloproliferative Neoplasms


Kathryn Foucar, MD








Blood smear from a patient with MDS/MPN shows marked leukocytosis with left shift. The patient also has a moderate anemia, while the platelet count is preserved. Note dysplastic neutrophils image.






Marked dysplastic features of neutrophils are evident in this peripheral blood smear from a patient with MDS/MPN. Note the nuclear segmentation abnormalities and hypogranularity of the neutrophil image.


TERMINOLOGY


Abbreviations



  • Myelodysplastic/myeloproliferative neoplasms (MDS/MPN)


Definitions



  • De novo clonal chronic myeloid neoplasm characterized by hybrid myelodysplastic and myeloproliferative features manifested by at least 1 cytopenia and at least 1 cytosis in blood


  • Maturation is intact, mature cells predominate


  • Blasts and blast equivalents are < 20% in blood and bone marrow


  • Multiple subtypes defined with specific criteria


WHO 2008 Classification of MDS/MPN



  • Chronic myelomonocytic leukemia (CMML)


  • Atypical chronic myeloid leukemia, BCR-ABL1 negative (aCML)


  • Juvenile myelomonocytic leukemia (JMML)


  • Myelodysplastic/myeloproliferative neoplasm, unclassifiable (MDS/MPN-U)


  • Refractory anemia with ring sideroblasts and thrombocytosis (RARS-T) (provisional category)


ETIOLOGY/PATHOGENESIS


Molecular Genetic Findings



  • No disease defining molecular/cytogenetic features


  • Aberrations in RAS/MAPK signaling pathways common and linked to abnormal cell proliferation



    • May include mutations in PTNPN11, NRAS, KRAS, or NF1 most notably in JMML


  • Many exclusionary genetic findings including absence of BCR-ABL1, PDGFRA/B, FGFR1 mutations, isolated del(5q), inv3(q21q26), and AML-defining translocations



    • All of these mutations are pathogenetically linked to other types of myeloid neoplasms

Jun 13, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Overview of Myelodysplastic/Myeloproliferative Neoplasms
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