Differential Diagnosis of Lipomatous Tumors Using 18F-Fluorodeoxygulcose Positron Emission Tomography/Computed Tomography: A Retrospective Observational Study.

Background/Aim: Lipomatous tumors, including lipomas, atypical lipomatous tumors (ALTs), myxoid liposarcomas (MLs), and dedifferentiated liposarcomas (DLs), are often diagnosed using magnetic resonance imaging (MRI). Differential diagnosis of lipomas and ALTs by MRI is often challenging. ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) has recently been used for the diagnosis and evaluation of tumor staging and recurrence of soft tissue tumors. The maximum standardized uptake value (SUV_max) is positively associated with malignant grade in several cancers. This study aimed to evaluate SUV_max of ¹⁸F-FDG PET/CT in the differential diagnosis of lipomatous tumors. Patients and Methods: Patients who underwent ¹⁸F-FDG PET/CT for the diagnosis of lipomatous tumors between January 2013 and September 2021 were included in the study. Patients with lipomatous tumors, confirmed by pathological diagnosis or surgical specimens, were evaluated for lipomatous tumor SUV_max. Results: This study included 44 patients with lipomas (n=19), ALTs (n=12), MLs (n=9), and DLs (n=4). The mean SUV_max of lipomas, ALTs, MLs, and DLs was 0.99±1.41, 1.92±0.95, 5.21±4.94, and 9.29±1.43, respectively. Lipomas showed a significantly lower SUV_max than did ALTs, MLs, and DLs (p<0.05). ALTs demonstrated a significantly lower SUV_max than did MLs and DLs (p<0.05). No significant differences were observed between MLs and DLs. Conclusion: Lipomas or ALTs had a significantly lower SUV_max than lipomatous sarcomas. Lipomas had a significantly lower SUV_max than ALTs, aiding in their preoperative differentiation. ¹⁸F-FDGPET/CT could serve as a potent tool for the differential diagnosis of lipomatous tumors. [ABSTRACT FROM AUTHOR]