A 24-year-old man was admitted with fever and rhinostenosis. A bulky mass was observed in his left nasal cavity. A biopsy showed diffuse proliferation of large atypical lymphocytes, which were positive for CD45RO, CD56, MIB-1, and EBER. Bone marrow aspiration showed many histiocytes with active hemophagocytosis. A diagnosis of nasal NK cell lymphoma with hemophagocytic syndrome (clinical stage IVB) was made. Following CHOP regimen chemotherapy, the tumor transiently reduced in size, but the patient developed multiple organ failure possibly due to tumor lysis syndrome. His general condition was improved by intensive supporting therapy. Two weeks later, the tumor again got worse. Despite salvage chemotherapy with a P-IMVP16/CBDCA regimen, the patient died of multiple organ failure due to tumor lysis syndrome. Autopsy revealed diffuse necrosis and fibrosis without proliferation of lymphoma cells in the liver, spleen, bone marrow, and lymph nodes. During the clinical course, hypercytokinemia including soluble IL-2 receptor, interferon-gamma and IL-18 was observed. The poor prognosis of NK/T cell lymphoma might be associated with massive tissue damage with hypercytokinemia.