Aggressive granular lymphocyte leukemia of natural killer cell type in an elderly patient

A 75-year-old man was admitted to our hospital because of intermittent fever. His peripheral blood picture showed granular lymphocyte (GL) proliferation. The GLs were immunologically and functionally phenotyped as natural killer cells. Chromosomal analysis of peripheral lymphocytes with interleukin-2 stimulation revealed an inversion of chromosome 9 with an unusual breakpoint, showing abnormal monoclonal proliferation of the GLs. Progressive increase of GL count and hepatosplenomegaly necessitated the start of combined chemotherapy. His condition was complicated by icterus and renal failure, and he died finally of respiratory failure. Autopsy revealed disseminated intravascular coagulation and infiltration of GLs in the bone marrow, spleen, and liver.