Primary NK/T cell lymphoma of the testis. A case report and review of the literature.

We report a case of aggressive 'nasal type' natural killer (NK)/T cell lymphoma initially presenting as a testicular tumor in a Korean man, which quickly took a fatal course by widespread dissemination. Histologically, the testicular mass showed a diffuse dense infiltrate of medium-sized and atypical large lymphoid cells with angiocentric and angiodestructive infiltration and areas of coagulative necrosis on hematoxylin-eosin stained sections. Immunophenotyping by immunohistochemistry yielded surface markers consistent with NK/T cell lymphoma. The Epstein-Barr virus genome was detected by in situ hybridization. During involved-field irradiation and chemotherapy following radical orchiectomy, the tumor disseminated shortly to the skin and soft tissue of his anterior chest wall and central nervous system (CNS). Identical lymphoid infiltrates were present in the patient's skin. CNS involvement was interpreted as having a leptomeningeal seeding. To the best of our knowledge, this is the 9th reported case of confirmed NK/T cell lymphoma arising from the testis. Relevant literature is reviewed, and the clinicopathologic features, natural history, and treatment options for primary testicular NK/T cell lymphoma are discussed.