Chest Wall Hibernoma With Intense 18F-FDG Uptake on PET/CT Mimicking Malignant Pleural Mesothelioma

A man in his 60s with asbestos exposure and pleural plaques was incidentally found to have a chest wall mass on computed tomography (CT). Positron emission tomography/CT (PET/CT) demonstrated intense 18F-fluorodeoxyglucose (FDG) uptake, raising concern for malignancy, including malignant pleural mesothelioma. CT and magnetic resonance imaging (MRI), however, showed a predominantly fat-containing lesion, suggesting hibernoma. Video-assisted thoracoscopic resection was performed, and histopathology confirmed hibernoma. Recognition of macroscopic fat on CT/MRI is essential to avoid misdiagnosis of FDG-avid benign lipomatous tumors.