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Case 30 - Discussion

Hematopathology Case

 

Large Granular Lymphocytic Leukemia (LGLL)

  • Definition:

    • Clonal proliferation of LGLs of the T-cell or NK-cell lineage

    • LGL count ≥ 2000/ÁL in peripheral blood

    • LGL lymphocytosis > 6 months

    • No identifiable cause for reactive LGL proliferation

  • Median age 55 years, M=F

  • Presentations: mostly cytopenia, especially neutropenia, commonly anemia, rarely pure red cell aplasia, splenomegaly ~50%

  • ~ 30% patients with rheumatoid arthritis (RA), ~1/3 of RA patients with neutropenia, ~40% Felty's syndrome patients with clonal T-LGLs

  • High frequency (~90%) of HLA-DR4 in T-LGLL patients with RA

  • Serum: rheumatoid factors+ ~60%,  ANA+ ~40%; high level of FasL (CD178) in most cases

  • Morphology:

    • Generally similar to polyclonal reactive LGLs

    • Typical LGL: abundant light blue cytoplasm with fine or occasionally coarse azurophilic granules; round or slightly indented nucleus; moderately condensed nuclear chromatin

    • Bone marrow: diffuse interstitial pattern, or in small clusters

  • Immunophenotype:

    • T-Cell Type (85%): CD2+, CD3+, CD4−, CD5+, CD7+, CD8+,CD11b+, CD16+, CD56-, CD57+, TRG@+

    • NK-Cell Type (15%): CD2+, CD3−, CD7+, CD8+, CD16+, CD56+, CD57+, TRG@

  • Typically indolent and nonprogressive