Abstract 4124313: An unusual case of pericardial mass

A 30-year-old male electrician presented with two days of fever and positional left shoulder pain and was found to have elevated inflammatory markers and a large pericardial effusion with echocardiographic evidence of tamponade for which he underwent pericardiocentesis. He was discharged on a course of anti-inflammatory therapy with presumed diagnosis of idiopathic pericarditis based on negative cytology. He returned 6 months later with several weeks of upper respiratory infection symptoms as well as new abdominal discomfort and emesis. On presentation, his vital signs were notable for tachycardia to 113 and cardiac exam was notable for tachycardia, regular rhythm, no rubs or murmurs, nondisplaced precordial impulse, normal jugular venous pressure with Kussmaul sign, and pulsus paradoxus of 6. An electrocardiogram showed sinus tachycardia with diffuse ST segment changes (Figure A). His cardiac biomarkers were unremarkable (troponin 21). His labs revealed normocytic anemia with hemoglobin of 11 and erythrocyte sediment rate above assay. Echocardiogram demonstrated a circumferential complex pericardial effusion with echocardiographic evidence of early tamponade (Figure B, C). A pericardiocentesis was attempted with inability to advance wire within pericardial space. A malignancy workup was initiated. CT demonstrated multi-station thoracic and lower cervical lymphadenopathy, moderate left pleural effusion, and an intrapericardial mass with associated pericardial effusion (Figure D). Cardiac magnetic resonance imaging demonstrated a circumferential intrapericardial non-mobile mass measuring up to 22 mm in thickness posteriorly and the mass was isointense to myocardium indicating low-fat content (Figure E). A supraclavicular lymph node biopsy was obtained with immunohistochemical staining positive for WT1 and calretinin, consistent with metastatic epithelioid mesothelioma of pericardial versus pleural etiology (Figure F). A PET-CT subsequently showed a FDG-avid circumferential anterior pericardial mass and multiple pleural-based lesions concerning for metastatic mesothelioma. He was initiated on pemetrexed/carboplatin systemic chemotherapy. With systemic therapy, his disease has been stable for 6 months. Pericardial mesothelioma is a rare malignancy. This case underscores the diagnostic challenges associated with pericardial mesothelioma and the importance of cancer workup as part of the pericardial effusion workup.