Philadelphia-chromosome-positive T-lymphoblastic leukemia: acute leukemia or chronic myelogenous leukemia blastic crisis

Acta Haematol. 2005;113(3):181-9. doi: 10.1159/000084448.


The Ph1 chromosome has rarely been reported in T-lineage acute lymphoblastic leukemia (T-ALL), and the clinical relevance of this translocation in T-ALL is currently unknown. In chronic myelogenous leukemia (CML) some data indicate derivation of T-cells from the leukemic clone and only a few cases of T-derived blastic crisis have been reported and quite often disputed. Particularly in cases identified initially in blastic crisis it may be difficult to distinguish those from Ph1-positive T-ALL. We herein report 2 patients who presented with a clinical picture of Ph1-positive T-ALL and who raised a differential diagnosis from T-cell blastic crisis of CML. We review the literature and suggest clinical and laboratory features that can help in the diagnosis. According to our literature review, 23 cases of Ph1-positive T-ALL and 44 cases of T-cell blastic crisis of CML, including ours, were reported. Some major differences between the two entities could help in establishing a diagnosis of Ph1-positive T-cell blastic crisis of CML vs. Ph1-positive T-ALL: Male sex and younger age was more predominant in T-ALL. While in most cases of CML blastic crisis there was a history of CML there was no such history in the T-ALL cases. Medullary involvement with lymphoblastic leukemia was present in all cases of T-ALL but only in about half of the cases of CML blastic crisis. None of the CML-blastic crisis cases tested by RT-PCR showed the minor breakpoint transcript, while 2 cases with T-ALL had the minor breakpoint transcript and 1 had both transcripts. Combined morphologic and FISH analysis can help to distinguish between the two entities and was applied in one of our cases. Although both entities carry a severe prognosis, differentiating between them might have clinical relevance, especially in the imatinib era.

Publication types

  • Case Reports

MeSH terms

  • Blast Crisis / genetics
  • Blast Crisis / pathology*
  • Cell Lineage* / genetics
  • Diagnosis, Differential
  • Female
  • Fusion Proteins, bcr-abl / genetics
  • Humans
  • In Situ Hybridization, Fluorescence
  • Karyotyping
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / genetics
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / pathology*
  • Leukemia-Lymphoma, Adult T-Cell / genetics
  • Leukemia-Lymphoma, Adult T-Cell / pathology*
  • Male
  • Middle Aged
  • Philadelphia Chromosome*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Translocation, Genetic / genetics


  • Fusion Proteins, bcr-abl