Abstract
BACKGROUND: Primary pericardial sarcomas are extremely rare malignancies. In this case of primary pericardial synovial sarcoma, we discuss the initial steps to work-up pericardial effusions and review features that warrant more detailed investigation. CASE SUMMARY: A 29-year-old male with no relevant past medical history presents with a few weeks of fatigue, dyspnoea, orthopnoea, leg swelling, and back pain. Transthoracic echocardiogram revealed pericardial effusion for which pericardiocentesis and drain placement were done. He was discharged with a diagnosis of post-viral pericarditis. He returned 5 months later with worsening symptoms. Advanced imaging with cardiac magnetic resonance imaging (CMR) showed heterogeneous pericardial mass later revealed to be a high-grade synovial sarcoma on biopsy. The patient was started on a doxorubicin-based chemotherapy regimen, but due to kidney dysfunction and multi-organ failure, he was transitioned to palliative care measures. DISCUSSION: Transthoracic echocardiogram and computed tomography are often the initial tests of choice for pericardial effusions with pericardiocentesis recommended for effusions with tamponade physiology, for moderate-to-large effusions, or if there is concern for infection/neoplasm. Due to improved tissue characterization and spatial resolution, CMR and positron emission tomography should also be considered for atypical or recurrent pericardial effusions to assess for less common aetiologies such as malignancy.