A Case of Extranodal NK/T-Cell Lymphoma, Nasal Type with Predominant Pharyngeal Lesion

Abstract

Extranodal NK/T-cell lymphoma, nasal type, which is referred as nasal NK/T cell lymphoma, is an Epstein-Barr virus (EBV)-associated tumor derived from NK or T cells. It frequently occurs in the nasal cavity and shows poor prognosis. H&E staining usually shows necrosis and inflammatory cell infiltration, which results in difficulties in correctly diagnosing this disease. A 63-year-old man with sore throat showing tumorous lesions in the nasopharynx and oropharynx was referred to us. Biopsies were taken from both lesions; however, they showed necrosis and granulation. We therefore performed serum EBV titer test, which showed 1:640 for VCA-IgG, 1:10 for VCA-IgA, <1:10 for EA-IgG, and <1:10 for EA-IgA, suggesting mild elevation compared with a general titer pattern of past infection. Based on the results of the titer test, nasal NK/T cell lymphoma was the most possible, which was then definitively diagnosed by additional biopsy. It has been reported that elevation of serum EBV titer in nasal NK/T cell lymphoma is not common despite its relation to EBV. Because biopsy frequently shows necrosis and granulation, it is important to evaluate serum EBV titer when clinical findings suggest this disease.