Objective: To explore the hematopathologic features of T-cell large granular lymphocytic leukemia (T-LGLL).
Methods: A retrospective analysis of the clinical presentation, bone marrow morphology, immunophenotyping and T-cell receptor gene rearrangement status were performed in 19 patients with T-LGLL.
Results: Of 19 patients, the most frequent hematological abnormalities were anemia and neutropenia (16/19 and 17/19 patients, respectively). Large granular lymphocytes (LGLs) were observed in 17 of 19 peripheral blood smears and 15 of 19 bone marrow aspirate specimens. Lymphocytosis (> 0.2) was present in 17 of 19 patients in their bone marrow aspirate specimens. Bone marrow biopsy specimens revealed lymphocytosis in 16 cases, with a mild to moderate increase of lymphocytes observed in 12 cases (12/16). The pattern of lymphoid distribution was interstitial in bone marrow sections. Intravascular distribution was seen in 8 cases. Lymphoid nodules were present in 4 cases. Flow cytometery showed an immunophenotype of CD3(+) CD4(-) CD8(+) CD56(-) CD57(+) of the tumor cells in 13 cases. Of the other 6 cases, the immunophenotypes included CD8(-) (1 case), CD56(+) (2 cases) and CD57(-) (3 cases). Immunohistochemistry showed CD3+ (10/10), CD57+ (3/3), CD8+ (6/7), TIA-1+ (6/7), granzyme B+ (4/7), perforin + (1/7), CD4- (4/4) and CD56- (9/9). Clonal T-cell receptor γ gene rearrangement by PCR was detected in 12 cases (12/17).
Conclusions: Hematopathologic features of most T-LGLL are distinct. Morphologic, immunophenotypic and molecular analysis of both peripheral blood and bone marrow specimens are essential and complementary in the diagnosis and differential diagnosis of T-LGLL.