[A case of primary effusion lymphoma effectively treated by oral corticosteroid therapy].

Primary effusion lymphoma is a rare type of lymphoma which is confined to those body cavities associated with human herpes virus 8 infection in its development. We describe a 93-year-old man with primary effusion lymphoma in the pleura, but who was negative for herpes virus 8 infection. Chest computed tomography revealed bilateral pleural effusion, but did not show any evidence of a tumor mass or lymph node enlargement. Cytological analysis of his pleural effusion revealed atypical lymphoid cells with immunophenotypes which were positive for CD10, CD19 and CD20. Clonal rearrangement of the immunoglobulin-heavy chain gene was detected by Southern blot analysis, and a diagnosis of primary effusion lymphoma was made. Although dyspnea and severe hypoxia developed, accompanied with increased pleural effusion, chemotherapy was not indicated because of his age. We thus tried oral corticosteroid therapy for palliation which resulted in a dramatic, long-term decrease of his pleural effusion. We present a rare case of primary effusion lymphoma effectively controlled by corticosteroid therapy.