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acute erythroid leukemia

Monday 23 August 2004

erythroleukemia (EL)

Historically, AML with erythroid features has been designated M6 by the French-American-British (FAB) group. The FAB criteria for M6 diagnosis are: bone marrow erythroblasts equal to or greater than 50% and blasts equal to or greater than 30% of the non-erythroid cells.

The World Health Organization (WHO) have recently recommended that the requisite blast percentage for a diagnosis of AML be 20% or greater, and this includes erythroid leukaemia. AML M6 would equate to the new WHO definition of erythroleukaemia (erythroid/myeloid). If there are less than 20% blasts, the diagnosis is refractory anaemia with an excess of blasts (RAEB).

Trilineage dysplasia is common but is not a prerequisite for diagnosis. Erythroid dysplasia may manifest as binuclearity, nucleocytoplasmic asynchrony and vacuolation.

The morphological appearance of the myeloblasts is not characteristic and they may contain Auer rods. Myeloperoxidase and Sudan black B stains may be positive in the myeloblasts. The iron stain may show ringed sideroblasts and PAS may be positive in the erythroid precursors in a block or diffuse pattern.

Cytogenetics

- clonal chromosomal abnormalities (76%)

  • 4 subgroups according to ploidy status
  • pseudodiploid (16%)
  • hypodiploid (47%)
  • hyperdiploid (19%)
  • 18% mixed cases associating 2 different clones (hypodiploid + hyperdiploid) or (pseudodiploid + hyperdiploid)

- Complex rearrangements and hypodiploid chromosome number (50%)

  • partial or entire monosomies (56%)
  • Chr.5
  • Chr.7
  • Chr.8
  • Chr.16
  • Chr.21

- BCR-ABL fusion in pure erythroid" leukemia (57%)

refractory anemia with excess of blasts in transformation (RAEB-t)

Variants

- congenital erythroleukemia

References

- Lessard M, Struski S, Leymarie V, Flandrin G, Lafage-Pochitaloff M, Mozziconacci MJ, Talmant P, Bastard C, Charrin C, Baranger L, Helias C, Cornillet-Lefebvre P, Mugneret F, Cabrol C, Pages MP, Fert-Ferret D, Nguyen-Khac F, Quilichini B, Barin C, Berger R, The Groupe Francais d’Hematologie Cellulaire Gfhc; on behalf of the Groupe Francophone de Cytogenetique Hematologique (GFCH). Cytogenetic study of 75 erythroleukemias. Cancer Genet Cytogenet. 2005 Dec;163(2):113-22. PMID: 16337853