RESUMEN
Primary testicular lymphoma account for 1~5% of all testicular neoplasms. The majority of these tumors are diffuse large B-cell non-Hodgkin lymphoma. Primary NK/T cell lymphoma of the testis is a rare entity. Regardless of treatment, the majority of these patients have exhibited a highly aggressive clinical course and they have died within 1 year because of early dissemination. We report here on a case of the aggressive 'nasal type' natural killer (NK)/T cell lymphoma that initially presented as a testicular tumor. A 63-year-old man presented with painless left testicular swelling, and so a left orchiectomy was performed. A biopsy specimen of the testis revealed an extranodal NK/T cell lymphoma of the nasal type. In-situ hybridization for Epstein-Barr virus proved positive. The patient received systemic chemotherapy with 3 courses of a combination regimen.