title: Adult T-cell leukemia/lymphoma with an unusual CD1a positive phenotype.
abstract: BACKGROUND
  Acute T-cell leukemia lymphoma (ATLL) tumor cells generally express CD2/CD3/CD5, but lack CD7. These T cells are usually CD4+CD8- and strongly express CD25, although some variability in this basic pattern may be found. Here we report a case with a very unusual CD1a positive phenotype.
  
  
  METHODS
  Samples from peripheral blood, bone marrow aspirate, lymph node, and cerebrospinal fluid obtained from a 45-year-old male patient with a T-cell lymphoproliferative disorder were immunophenotyped by multiparametric flow cytometry. Analysis of HTLV-I genome integration in tumoral cells was performed by PCR.
  
  
  RESULTS
  Neoplastic T cells were cCD3, CD2/CD5/CD30/CD25, and CD1a positive, but CD3/CD7/CD4/CD8/CD34/CD10/TdT negative. Serology and integration of HTLV-I were positive.
  
  
  CONCLUSIONS
  To the best of our knowledge, CD1a expression has not been previously described in this entity. Its detection raised the differential diagnosis with acute T lymphoblastic leukemia. The rest of the phenotypic markers, the morphology of the neoplastic cells, and the demonstration of HTLV-I genome integration provided the final diagnosis.
authors.affiliation: IJC, Hematology Laboratory, ICO, Hospital Germans Trias i Pujol. Badalona, (Barcelona), Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Juncà
authors.forename: Teresa
authors.initials: T
authors.lastname: Botín
authors.forename: Jordi
authors.initials: J
authors.lastname: Vila
authors.forename: Josep-Tomàs
authors.initials: JT
authors.lastname: Navarro
authors.forename: Fuensanta
authors.initials: F
authors.lastname: Millá
mesh_terms: D018949:Antigens, CD1 / Q000032:analysis*; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000175:diagnosis* / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000821:virology
chemical_list: D018949:Antigens, CD1; C419393:CD1a antigen
keywords: ATLL; CD1a