Isolated central nervous system involvement in adult T‐cell lymphoma/leukaemia

Summary Central nervous system (CNS) presentation of adult T-cell lymphoma/ leukaemia is rare, and almost invariably associated with systemic disease. We report an unusual manifestation of adult T-cell lymphoma/leukaemia, with isolated CNS involvement and unusual imaging findings. We also describe objective response to antiviral therapy. To our knowledge, this is the first report of such presentation and response.