We report a case of aggressive natural killer (NK) cell lymphoma in an 82 year old man who first presented 10 years earlier with neutropenia in association with a large granular lymphocyte (LGL) lymphocytosis. The diagnosis of NK cell lymphoma was made on the basis of morphological and immunological characteristics (CD3-CD56+) found on skin biopsy of one of multiple skin nodules which subsequently developed in association with splenomegaly, thrombocytopenia and continuing neutropenia. In addition there was BM infiltration and a cytogenetic abnormality [add(6)(p25)] was detected. Combination chemotherapy led to an initial clinical response but a relapse occurred shortly afterwards and the patient died 8 months later from infection whilst neutropenic following re-introduction of chemotherapy. Previously reported cases of aggressive NK cell lymphoma have shown a young male predominance with a rapidly progressive clinical course and without evidence of a preceding chronic phase of LGL lymphocytosis and neutropenia.