فهرست نشریات علمی دسترسی آزاد ایران

Synchronous primary tumors (SPTs) refer to the pathologically different tumors coexisting in an individual. This phenomenon is often identified during cancer evaluation using [18F]fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT). The two cases presented here highlight discrepancies in [¹⁸F]FDG uptake intensity between the SPTs. Case 1 features a breast cancer with high uptake and a second primary lung cancer with low uptake, while Case 2 describes an esophageal cancer with low uptake and an incidental paraganglioma with high uptake. [¹⁸F]FDG uptake varies by histopathological characteristics and is typically consistent within the same clonal group. A lesion showing discordant uptake relative to the primary tumor on [¹⁸F]FDG PET/CT may indicate another distinct tumor.