Blood/Blood Cells and Cellular Components ›› Lymphocytes ›› Abnormal

Large Granular Lymphocyte (LGL)*

Microscopic Features:
  • 2-4x larger than a mature RBC
  • Low nuclear to cytoplasmic ratio because of the increased cytoplasm
  • Round-to-convoluted nuclear border with mature chromatin (clumped chromatin)
  • Nucleoli are absent
  • Cytoplasm is abundant, light blue
  • Pink/red granules in the cytoplasm (hence the term "granular")
Normal % blood-PB, marrow-BM, lymphoid tissue-LN:
  • PB: Rare to None
  • BM: None
  • LN: None
May Resemble:
  • Reactive lymphocyte
  • Monocyte
  • Promyelocyte
Differential Diagnoses:

If increased in blood or bone marrow:
Neoplastic (LGL leukemia)

Classic Immunophenotype:
  • CD2+
  • CD3+
  • CD4-
  • CD8+
  • CD5+
  • CD7+
  • CD56+
Cartoon Image:

  • Must rule out reactive conditions (e.g. infection, etc.) before considering LGL leukemia as a diagnosis