RESUMO
T cell large granular lymphocytic leukemia (T-LGL leukemia) is defined as a clonal proliferative disorder of CD3+ cytotoxic T cells. T-LGL leukemia usually expresses CD3+, CD4-, CD8+, CD16+, CD56- and CD57+ cell markers, and this represents a rearrangement of the T cell receptor (TCR) gene. The clinical course is indolent in most cases, but on rare occasions, when CD3+ and CD56+ are expressed on the leukemic cells, it can be more aggressive. We experienced a patient with T-LGL leukemia and the disease was indolent at the time of diagnosis, and so any specific treatment was not required. Two years after the initial diagnosis, her clinical course became quite aggressive as the CD 56+ cell surface antigen was expressed. We report here on the first case of T-LGL leukemia in Korea and we review the relevant literature.