title: How unique is pure erythroid leukaemia? A retrospective analysis of seven cases and review of the literature.
abstract: OBJECTIVE
  Pure erythroid leukaemia (PEL) is a rare subtype of acute myeloid leukaemia (AML) and its clinicopathological features are not well-defined. The aim of this study was to describe the immunophenotypic, cytogenetic and clinical features of PEL and to compare these with cases of AML with ≥ 50% erythroblasts.
  
  
  METHODS
  Cases of PEL according to WHO morphological criteria diagnosed at three institutions from 1997 to 2013 were included. A comparison cohort comprised of AML with ≥ 50% erythroblasts. The clinical, histopathology, immunophenotypic and cytogenetic features of cases were analysed. We also reviewed the existing literature on PEL, and combined our cohort with previously reported cases of PEL in a pooled analysis.
  
  
  RESULTS
  There were seven cases of PEL diagnosed at our institutions. There was a high incidence of either prior chemoradiotherapy exposure or evolution from pre-existing myelodysplastic syndrome (MDS) (71%). The leukaemic blasts frequently expressed glycophorin C (100%), CD117 (83%) and were myeloperoxidase negative (83%). Complex karyotypes were present in 83% of cases. Median overall survival was 2.9 months. Compared with AML with ≥ 50% erythroblasts, cases of PEL demonstrated a higher incidence of adverse-risk cytogenetics (p=0.01) and prior exposure to chemoradiotherapy (p=0.01).
  
  
  CONCLUSIONS
  PEL appears to be a unique entity that is often secondary or therapy related, commonly features a complex karyotype and has a poor prognosis. It is morphologically and immunophenotypically distinct from other cases of AML with erythroid hyperplasia.
authors.affiliation: Department of Diagnostic Haematology, Royal Melbourne Hospital, Melbourne, Victoria, Australia.
authors.forename: Eric
authors.initials: E
authors.lastname: Wong
authors.affiliation: Department of Diagnostic Haematology, Alfred Hospital, Melbourne, Victoria, Australia.
authors.forename: Victoria
authors.initials: V
authors.lastname: Ling
authors.affiliation: Department of Pathology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Westerman
authors.affiliation: Department of Pathology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: Susan
authors.initials: S
authors.lastname: Morgan
authors.affiliation: Department of Diagnostic Haematology, Royal Melbourne Hospital, Melbourne, Victoria, Australia University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Surender
authors.initials: S
authors.lastname: Juneja
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics; D049109:Cell Proliferation; D004900:Erythroblasts / Q000737:chemistry / Q000276:immunology / Q000473:pathology; D020022:Genetic Predisposition to Disease; D006801:Humans; D006965:Hyperplasia; D016130:Immunophenotyping; D059785:Karyotype; D007621:Karyotyping; D007948:Leukemia, Monocytic, Acute / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology* / Q000235:genetics / Q000276:immunology / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D014739:Victoria / Q000453:epidemiology; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor
keywords: CYTOGENETICS; HISTOPATHOLOGY; IMMUNOPHENOTYPING; LEUKAEMIA