Aggressive T-large granular lymphocytic leukemia with an aberrant natural killer T-cell phenotype in an adult and derivation of a novel cell line.

Aggressive T-cell large granular lymphocytic leukemia represents a rare but highly fatal clinical entity, starkly contrasting with the typically indolent nature of classic large granular lymphocytic leukemia. This report details the case of a female in her early 60s who succumbed to the disease merely 3 days after hospitalization, highlighting a precipitous clinical course from unremarkable blood test results to death within approximately 4 months. The diagnosis was confirmed by peripheral blood morphology, immunophenotyping, and molecular cytogenetic studies. The leukemic cells demonstrated a natural killer T-cell phenotype, clonal T-cell receptor rearrangement, and a complex karyotype. A significant outcome of this case was the successful establishment of a stable cell line derived from the patient's peripheral blood mononuclear cells. This case underscores the need for early recognition of this aggressive T-cell large granular lymphocytic leukemia variant. Furthermore, the novel cell line provides an invaluable and unprecedented resource for elucidating the underlying pathogenesis and exploring potential therapeutic strategies for this devastating malignancy.