A primary benign cardiac tumor misdiagnosed as cardiac metastasis in the right atrium

We present a patient with breast cancer with multiple metastases who had an unusual cardiac mass in the right atrium. The cardiac mass was initially diagnosed as malignant metastasis by transthoracic echocardiogram (TTE) but subsequently diagnosed as benign by contrast‐enhanced ultrasonography, cardiac magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT). TTE is the preferred imaging method for examination of cardiac masses. However, this case demonstrates that contrast‐enhanced ultrasonography, MRI, and PET/CT are useful to differentiate between diagnoses of benign and malignant tumor. The combination of multiple diagnostic imaging modalities is necessary to confirm the diagnosis of cardiac tumors.