ereport a case of T-cell-rich large B-cell lymphomademonstrating sick sinus syndrome as a single initial symptom, followed by the retention ofpericardial and pleural effusions. Intrapleural administration of interferon-a prevented reaccumulation of the pleural effusion for one and a half months, whereas systemic chemotherapy failed to control tumor growth in the skin and lymph nodes. The autopsy revealed involvement of the sinoatrial node of the heart by lymphomacells.