Coexistence of two distinct cell populations (CD56(+)TcRgammadelta(+) and CD56(+)TcRgammadelta(-)) in a case of aggressive CD56(+) lymphoma/leukemia.
OBJECTIVE
Large granular lymphocytes derive from two major lineages: one expressing the CD3 surface antigen (T-lymphocytes), and the other lacking this marker (NK-cells). Although developmental overlaps between natural killer cells and T-cells have been described, malignancies derived from these two cell types are considered as distinct lymphoid disorders.


METHODS
We report the case of a 30-year old man affected by a lymphoma/leukemia syndrome presenting with hepatosplenic lymphoma which rapidly transformed into aggressive NK-leukemia. Extensive flow cytometry studies and molecular analysis were repeated during the course of the disease, and showed an unexpected changing pattern.


RESULTS
At diagnosis, flow cytometry analysis showed the co-existence of two cell populations, one CD56(+), CD3(+), TcRgd(+), and the other CD56(+), CD3(-) and TcRgd(-). Molecular analysis showed that the TcR genes had the same clonally rearranged pattern involving b, g and d genes in both populations. At disease relapse and during the terminal refractory phase, only CD3(-) cells were present.


CONCLUSIONS
This is an unusual case of CD56(+) aggressive lymphoma/leukemia characterized by the clonal expansion of two phenotypically different cell populations, variably balanced during the course of the disease. The presence of the same TcR genomic rearrangement suggests the origin from a common progenitor able to differentiate along both T- and NK-pathways.
Camera
A
A
Divisione di Ematologia, Ospedale A. Cardarelli, Naples, Italy.
Pezzullo
L
L
Villa
M R
MR
Luciano
L
L
Pane
F
F
Izzo
B
B
Boccuni
P
P
Di Noto
R
R
Del Vecchio
L
L
Salvatore
F
F
Rotoli
B
B
D000328:Adult; D017252:CD3 Complex / Q000097:blood; D019002:CD56 Antigen / Q000097:blood*; D002999:Clone Cells; D020732:Cytogenetic Analysis; D018450:Disease Progression; D006801:Humans; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology; D007938:Leukemia / Q000097:blood / Q000276:immunology*; D008113:Liver Neoplasms / Q000097:blood / Q000276:immunology; D008223:Lymphoma / Q000097:blood / Q000276:immunology*; D008297:Male; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000097:blood / Q000235:genetics; D013160:Splenic Neoplasms / Q000097:blood / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology
D017252:CD3 Complex; D019002:CD56 Antigen; D016692:Receptors, Antigen, T-Cell, gamma-delta