Abstract
Primary pericardial synovial sarcoma is an extremely rare disease with a dismal prognosis. Its main presenting symptoms are a large pericardial effusion, signs of cardiac tamponade, and visualization of a pericardial mass on echocardiography. However, the systemic symptoms of fever, cough, and night sweats may present a clinical picture without any apparent pericardial mass on diagnostic imaging, potentially impeding the diagnosis. We report the case of a 34-year-old patient with fever and recurrent pericardial effusion for 2 years, who was diagnosed with primary pericardial synovial sarcoma after 2-year follow-up echocardiography.