Right Atrial Mass in a Middle-Aged Man

A middle-aged man presented with acute pulmonary embolism, multiple bilateral pulmonary nodules, mediastinal lymphadenopathy, and a 4.5 × 3.6 × 3.1-cm pedunculated right atrial mass attached to the interatrial septum near the fossa ovalis. Left ventricular (LV) function was reduced, and cardiac mechanics by 2-dimensional speckle-tracking strain was markedly abnormal, suggesting a more diffuse myocardial process. Cardiac magnetic resonance imaging revealed a more extensive infiltrative mass in the left atrioventricular (AV) groove with extension into the right and LV myocardium and coronary sinus, contiguous with the mass seen by echocardiogram. Positron emission tomography–computed tomography showed increased fluorodeoxyglucose uptake in the soft tissues of the heart, pulmonary nodules, and mediastinal lymph nodes, and cytogenetic testing of a biopsy sample confirmed metastatic primary cardiac synovial sarcoma. Click the Related Article link for complete case details and discussion.