Incidental 18F-Fluorodeoxyglucose Avid Cardiac Mass on Positron Emission Tomography-Computed Tomography in a Patient with Head-and-Neck Carcinoma

Figures

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  Figure 1. Maximum intensity projection PET images (a) showing focal 18F-FDG uptake in the left alveolar region (broken arrow) with another patchy 18F-FDG uptake in the cardiac region (arrow). Transaxial PET-CT image (b) showing primary left lower alveolar and retromolar trigone lesion (arrow) with bony erosion. On transaxial (c and d) and coronal (e and f) contrast-enhanced CT and fused PET-CT images, two lesions are also seen in the left atrium. The larger one (arrow) measuring about 41 mm × 35 mm in size, with poor enhancement, focal internal calcifications, and intense 18F-FDG uptake, raising differentials of atrial myxoma versus tumor thrombus, while the other lesion (bold arrow) is smaller and elongated, showing no significant enhancement or 18F-FDG uptake, suggestive of bland thrombus. 18F-FDG: 18F-fluorodeoxyglucose, PET-CT: Positron emission tomography-computed tomography

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  Figure 2. The larger left atrial mass (arrow) is hypointense on transaxial T1-weighted images (a), hyperintense on transaxial (b) and sagittal (c) T2-weighted images, with heterogeneous enhancement on coronal gadolinium-enhanced images (c) and is hyperintense relative to myocardium but hypointense relative to the blood pool in transaxial gradient-echo sequences (d). These findings suggest a diagnosis of atrial myxoma. The other left atrial lesion (broken arrow) is hypointense on both transaxial T1-weighted (f) and transaxial T2-weighted (g) images, with no significant gadolinium contrast enhancement (h), suggesting a chronic organized thrombus