Philadelphia-chromosome-positive T-lymphoblastic leukemia: acute leukemia or chronic myelogenous leukemia blastic crisis.
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.
Raanani
Pia
P
Institute of Hematology, Sheba Medical Center and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel. praanani@012.net.il
Trakhtenbrot
Luba
L
Rechavi
Gideon
G
Rosenthal
Esther
E
Avigdor
Abraham
A
Brok-Simoni
Frida
F
Leiba
Merav
M
Amariglio
Ninette
N
Nagler
Arnon
A
Ben-Bassat
Isaac
I
D001752:Blast Crisis / Q000235:genetics / Q000473:pathology*; D019070:Cell Lineage / Q000235:genetics; D003937:Diagnosis, Differential; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics / Q000473:pathology*; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000235:genetics / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010677:Philadelphia Chromosome; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014178:Translocation, Genetic / Q000235:genetics
D016044:Fusion Proteins, bcr-abl