Abstract
Adult T-cell leukemia/lymphoma (ATLL) is an aggressive matured T-cell lymphoma caused by human T-lymphotropic virus type I. In advanced stage, multiple organs including bone marrow, skin, liver, spleen, gastrointestinal tract and lung may be involved, in addition to the lymph nodes and peripheral blood. However, to our best of knowledge, no case of primary testicular ATLL has been previously reported: namely primary ATLL of immune privileged site. In this paper, we present a case of primary testicular ATLL case with a poor prognosis despite being in limited stage (Stage I). The report of primary testicular T-cell lymphoma is scant, and accumulation of cases is required.