Pneumopericardium masquerading as an acute myocardial infarction

We report a case of a 64-year-old woman with increasing shortness of breath due to massive pericardial effusion. Cardiac magnetic resonance imaging (CMRI) identified typical findings for pericarditis. Pericardectomy was needed due to suspicion of pericardial abscess formation. Histological examination of the resected tissue revealed an undifferentiated primary pericardial synovial sarcoma. The present case illustrates that pericardial tumours could be an important differential diagnosis to pericarditis, even if typical findings of pericarditis were present in CMRI.