Other Recurrent Cytogenetic Abnormalities
The remaining workshop cases highlighted unique genetic and/or clinical features of various cytogenetic subtypes (see Table 2). Although one topic of discussion at the workshop related to new potential AML-defining cytogenetic entities, there was no general consensus. Of the five cases with MLL rearrangement, case 251 was selected for presentation and discussion. Distinctive features included the myelomonocytic morphology, absence of NPM1 mutation, and uniquely aggressive disease course Image 15 and Image 16.
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Image 15.
Bone marrow aspirate smear shows a marked predominance of monoblasts and promonocytes in this patient with acute myeloid leukemia with t(6;11) (Wright, ×1,000). (Courtesy of R. E. Felgar, MD.)
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Image 16.
This combined esterase stain shows an admixture of immature granulocytic lineage cells (red) and immature monocytic cells (brown) in this case of acute myelomonocytic leukemia with t(6;11) (×1,000). (Courtesy of R. E. Felgar, MD.)
Myeloid neoplasms with inv(3) are challenging because many of these cases fulfill WHO 2008 criteria for MDS, as highlighted by case 342, for which the consensus diagnosis was refractory anemia with excess blasts 1 Image 17 and Image 18. This patient responded to MDS-directed therapy. Consequently, although large case series of inv(3)-associated myeloid neoplasms show adverse outcome regardless of myeloid-neoplasm subtype, some patients with inv(3)-associated MDS may benefit from less aggressive therapy. However, the risk of progression to overt AML is reportedly high in cases of MDS with inv(3).
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Image 17.
This bone marrow core biopsy section from a patient with refractory anemia with excess blasts 1 and inv(3) shows abnormal small dysplastic megakaryocytes (center) (H&E, ×400). (Courtesy of M. E. Salama, MD.)
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Image 18.
Immunoperoxidase staining for CD34 shows increased blasts with clustering in this case of refractory anemia with excess blasts 1 with inv(3) (×400). (Courtesy of M. E. Salama, MD.)