[Aggressive natural killer cell lymphoproliferative disease of large granular lymphocytes with leukemia-like clinical course in the terminalstage].

A 20-year-old man was admitted to our clinic with fever elevation up to 39 degrees C for two months, generalized lymphadenopathy and hepatosplenomegaly. Histological examination of right scalene lymph node with HE staining showed T cell lymphoma-like finding. The patient was given vindesine and prednisolone, and there was almost no clinical improvement. Abnormal large granular lymphocyte appeared in peripheral blood and increased up to 17,000/microliters in the terminal stage of clinical course. These lymphocytes had abundant pale cytoplasm with rich large azurophilic granules and a large nucleus with a few nucleoli. The phenotype of these cells were as follows: Fc gamma R+, CD2+, CD5-, CD7-, CD3-, CD4-, CD1-, CD8-, sIg-, CD20-, CD11-, CD13-, OKIa+, CD25-, CD16+, Leu7-. These cells did not have the activity of antibody dependent cellular cytotoxicity but had natural killer activity. The gene of T cell receptor (beta and gamma chain) did not rearranged in these cells. We concluded that the abnormal cells were derived from natural killer cells, which caused aggressive clinical course.