Extranodal NK/T-cell lymphoma, nasal type

Abstract

Extranodal natural killer (NK)/T-cell lymphoma (ENKL) is a unique disease entity that is strongly associated with Epstein-Barr virus (EBV) infection. This disease is more common in Asia and Central and South America but is rare in North America and Europe. Pathologically, ENKL involves polymorphous infiltration of variable-size lymphocytes with accompanying inflammation and necrosis. The malignant cells express cytoplasmic CD3 and CD56. EBV is detected by EBV-encoded small RNA (EBER) in situ hybridization. Unlike other aggressive lymphomas, around 80 % of cases are localized to the nasal and upper airway region. Skin, intestine, and testis are the common sites of involvement outside the nasal area. The prognosis is generally poor, with 30-40 % long-term survival. The Korean Prognostic Index (KPI) is more powerful than the International Prognostic Index (IPI) for predicting the prognosis. The response to anthracycline-based chemotherapies, such as CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) or CHOP-like regimens is disappointing: 30-40 % long-term survival, even for stage I or II cases. Concurrent chemoradiation strategies have a higher efficacy for localized ENKL treatment: 70-80 % long-term survival. For advanced disease, l-asparaginase-based polychemotherapy regimens are producing promising results.