AML with inv(3)(q21q26.2) or t(3;3)(q21;q26.1)

Related Cases: HP-281

  • Primarily in adults
  • Peripheral blood: Often thrombocytosis with giant agranular platelets
  • Bone marrow:
    • Often dysplastic
    • Characteristic unilobated or bilobated micromegakaryocytes
    • Blasts: myeloid, monocytic or megakaryoblastic
    • Blasts often express CD7+
  • Cytogenetics:
    • Not very sensitive in detecting EVI1 rearrangements, which are often cryptic
    • EVI1 rearrangements may be associated with rearrangements other than inv(3) and t(3;3)
    • Better use FISH for EVI1 rearrangement
    • Often associated with -7
  • EVI1, an antagonist of GATA-1
  • Poor prognosis
  • Note: The morphologic features of the dysplastic megakaryocytes are unique for MDS/AML with EVI1 rearrangement, and the megakaryocytes are usually small and have one, two or more separated nuclei. The nuclei are typically round and different to those in CML and MDS with 5q deletion, which are small with irregular nuclear contours. In cases with negative cytogenetics, the presence of these atypical megakaryocytes should prompt the FISH studies for EVI1 rearrangement. However, the megakaryocytes with these morphologic features can also been noted in other MDS, AML or even reactive conditions after chemotherapy or transplant.

Reference

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Last updated: 05/10/2015