T-cell large granular lymphocytic leukemia of cd4-/cd8-γδ variant

T-cell large granular lymphocytic (T-LGL) leukemia is a distinct entity of mature T-cell lymphoma/leukemia characterized by a clonal proliferation of LGLs (usually between 2 and 20 × 10/L), splenomegaly, and cytopenia, most commonly severe neutropenia and/or anemia. T-cell large granular lymphocytic leukemia is typically derived from the CD3, CD8, and T-cell receptor αβ cytotoxic T cells, with a small number of cases arising from T-cell receptor γδ T cells. There is no agreement on the peripheral LGL count required for the diagnosis; cases with a LGL count less than 2 × 10/L that meet all other appropriate criteria of T-LGL leukemia are consistent with the diagnosis. Here, we report a case of CD4/CD8 γδ T-LGL leukemia in a 70-year-old man who presented with hemolytic anemia for more than a year. Extensive clinical workup did not reveal the cause. A bone marrow biopsy was performed and demonstrated diffuse involvement by a CD4/CD8 γδ T-LGL leukemia despite the lack of peripheral blood lymphocytosis or increased LGLs. The clinicopathologic features of T-LGL leukemia and the differential diagnosis are discussed.