We report the clinical and laboratory findings of a patient with an aggressive Epstein-Barr virus positive CD2+/CD56+ natural killer-cell lymphoma with a high mitotic activity and complex chromosomal abnormalities presenting with life-threatening pericardial and pleural effusions, disseminated skin lesions, breast nodule and large suprarenal masses. The clinical course was characterized by resistance to chemotherapy and relapsing pericardial and pleural effusions with respiratory and haemodynamic failure. Death occurred 4 months after the first manifestations of the disease as a consequence of cardiac tamponade.