Incidental (18)F-Fluorodeoxyglucose Avid Cardiac Mass on Positron Emission Tomography-Computed Tomography in a Patient with Head-and-Neck Carcinoma: Metastasis or Something Else?

High (18)F-Fluorodeoxyglucose ((18)F-FDG) uptake in a cardiac mass is considered to be a marker of malignancy, but that is not always true. We here present such a case of incidentally detected (18)F-FDG cardiac mass on staging positron emission tomography-computed tomography in a woman with head-and-neck cancer, confirmed to be myxoma on contrast-enhanced magnetic resonance imaging and subsequent histopathology.