title: Clinical, hematological and cytogenetic characteristics of atypical chronic myeloid leukemia.
abstract: BACKGROUND
  Atypical chronic myeloid leukemia (aCML) is an infrequent chronic myeloproliferative disorder characterized by leukocytosis, absence of Philadelphia chromosome or BCR-ABL rearrangement, and marked myeloid dysplasia. Some cases have an absolute monocytosis but can be distinguished from chronic myelomonocytic leukemia (CMML) by the presence of a higher percentage (> 15%) of circulating immature granulocytes.
  
  
  METHODS
  In a series of 11 patients with a diagnosis of aCML according to the FAB proposals we have analyzed the most relevant clinical, hematological and cytogenetic characteristics.
  
  
  RESULTS
  The median age was 65 years (16-84). All but one case showed, at time of diagnosis, leukocytosis (median WBC was 36 x 10(9)/l), 55% had moderate anemia and 36% had thrombocytopenia. Most cases had marked dysplasia, particularly in the granulocytic lineage (82% of the cases), and all cases showed bone marrow red hypoplasia. Cytogenetic abnormalities were present in 9 out of the 11 patients. Trisomy 8 was observed in three cases and other clonal chromosomal abnormalities included deletions of 5q, 13q, 17p, 12q, and 11q as well as a t(6;8)(p23;q22) translocation. Fluorescence in situ hybridization (FISH) studies failed to demonstrate ETV-6 gene involvement. The median survival time from diagnosis was only 14 months (range 3-56 months).
  
  
  CONCLUSIONS
  These data suggest that aCML is a rare disease which is characterized by leukocytosis, with dysgranulopoiesis, BM erythroid hypoplasia, chromosomal, though not recurrent, abnormalities and poor prognosis.
authors.affiliation: Department of Hematology, Hospital Universitario and Centro de Investigación del Cáncer, Universidad de Salamanca-CSIC, Spain. jmhernandezr@aehh.org
authors.forename: J M
authors.initials: JM
authors.lastname: Hernández
authors.forename: M C
authors.initials: MC
authors.lastname: del Cañizo
authors.forename: A
authors.initials: A
authors.lastname: Cuneo
authors.forename: J L
authors.initials: JL
authors.lastname: García
authors.forename: N C
authors.initials: NC
authors.lastname: Gutiérrez
authors.forename: M
authors.initials: M
authors.lastname: González
authors.forename: G
authors.initials: G
authors.lastname: Castoldi
authors.forename: J F
authors.initials: JF
authors.lastname: San Miguel
mesh_terms: D000293:Adolescent; D000368:Aged; D000740:Anemia; D001854:Bone Marrow Cells / Q000473:pathology; D002869:Chromosome Aberrations; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000145:classification / Q000235:genetics / Q000473:pathology*; D007964:Leukocytosis; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016019:Survival Analysis; D013921:Thrombocytopenia