Incidental focal ¹⁸F-FDG uptake in the frontal process of the maxilla on PET/CT: prevalence and clinical significance

Objective: We investigated the prevalence and clinical significance of incidental focal ¹⁸F-FDG uptake in the frontal process of the maxilla, mimicking malignancy on PET/CT. Methods: From a total of 32,834 patients who underwent ¹⁸F-FDG PET/CT, patients with focal uptake in the frontal process of the maxilla were selected by a database search. For those patients, medical records including relevant imaging studies were reviewed. Results: Thirty-nine patients (0.12 %) demonstrated focal uptake on PET/CT. On CT of PET/CT, all lesions showed ground-glass attenuation with or without bony expansion, consistent with fibrous dysplasia. When comparing previous PET/CT, follow-up PET/CT, and CT, a significant difference in degree of ¹⁸F-FDG uptake was noted, with no associated change in the size of maxillary lesions. There were no patients who had symptoms or signs related to maxillary lesions during follow-up. Conclusion: Focal ¹⁸F-FDG uptake in the frontal process of the maxilla is a rare, incidental, and persistent finding with variable uptake and can represent a benign condition.