Cardiac tamponade was manifested in a 30-year-old male with a 6-month
history of fever and weight loss prior to admission. Cross-sectional e
chocardiography demonstrated huge pericardial effusion with a Large ma
ss in the posterior pericardial space. Pericardiocentesis revealed exu
dative fluid with no malignant cells. Surgery performed to determine t
he nature of the mass disclosed the mass originating from the posterio
r pericardium, invading the posterior pleural sac and adjacent structu
res. Histopathology identified spindle cell sarcoma. The preoperative
diagnosis of the mass and its presenting features and nature are discu
ssed.