title: Hidden mastocytosis in acute myeloid leukemia with t(8;21)(q22;q22).
abstract: OBJECTIVE
  To assess the frequency of systemic mastocytosis (SM) in a large series of acute myeloid leukemia (AML) with t(8;21)(q22;q22).
  
  
  METHODS
  We retrospectively characterized 40 bone marrow aspirate smears and biopsy specimens from patients with AML with t(8;21) for the presence of SM. Cases were assessed for mast cell morphology and immunohistochemistry, as well as KIT exon 8 and 17 mutational assessment by reverse transcription polymerase chain reaction.
  
  
  RESULTS
  Four patients met criteria for SM, 1 met criteria for myelomastocytic leukemia, and 8 demonstrated the benign finding of mast cell hyperplasia.
  
  
  CONCLUSIONS
  We recommend examining all cases of AML with t(8;21) for the presence of SM via morphology, immunophenotyping, and KIT mutational analysis studies.
authors.affiliation: Dept of Pathology, Stanford University School of Medicine, 300 Pasteur Dr, MC 5324, Stanford, CA 94086; e-mail: ryancj@stanford.edu.
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Johnson
authors.forename: Natasha M
authors.initials: NM
authors.lastname: Savage
authors.forename: Tsoyu
authors.initials: T
authors.lastname: Chiang
authors.forename: Jason R
authors.initials: JR
authors.lastname: Gotlib
authors.forename: Athena M
authors.initials: AM
authors.lastname: Cherry
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Arber
authors.forename: Tracy I
authors.initials: TI
authors.lastname: George
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001854:Bone Marrow Cells / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D002891:Chromosomes, Human, Pair 21; D002898:Chromosomes, Human, Pair 8; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D006965:Hyperplasia; D015470:Leukemia, Myeloid, Acute / Q000150:complications / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008407:Mast Cells / Q000473:pathology; D034721:Mastocytosis, Systemic / Q000150:complications / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics; D012189:Retrospective Studies; D014178:Translocation, Genetic; D055815:Young Adult
chemical_list: D019009:Proto-Oncogene Proteins c-kit
keywords: AML with t(8;21); CD25; D816V; Exon 17 KIT mutations; Myelomastocytic leukemia; N822K; Systemic mastocytosis; Tryptase