Steady-state free precession magnetic resonance image demonstrating a broad based, isointense structure (black arrow) measuring 3 cm × 1 cm arising from the lateral wall of the right atrium adjacent to the atrioventricular junction of the right atrium. Connected to this broad based mass is an isodense, circular, well-circumscribed mass (red arrow) measuring 1 cm in diameter protruding from the broad based mass into the right atrium. RA: right atrium, RV: right ventricle, LA: left atrium, LV: left ventricle.