Incidental frontal process of the maxilla uptake on bone scintigraphy: a benign phenomenon validated by multimodal imaging and metabolic stability

Objectives To characterize incidental radiotracer uptake in the frontal process of the maxilla (FPM) on bone scintigraphy and evaluate its clinical significance through multimodal correlation. Methods This retrospective study (2019–2024) included 51 patients with incidental FPM uptake identified among 1,898 whole-body bone scintigrams. Subsets underwent follow-up bone scintigraphy (n = 15) or anatomical/molecular imaging with CT or fluorine-18 fluorodeoxyglucose (FDG) PET/CT (n = 24). Assessments included: quantitative target-to-nontarget ratios; CT morphology (attenuation patterns, bony expansion, dimensions); metabolic activity (maximum standardized uptake value) on PET/CT; longitudinal target-to-nontarget ratio changes. Results The phenomenon prevalence was 2.7% (51/1,898). Scintigraphy revealed unilateral foci in 96.1% of cases with median target-to-nontarget ratio of 4.2. Follow-up at median 14.0 months demonstrated visual stability in 80% of lesions (12/15) and non-significant target-to-nontarget ratio change ( p = 0.727). CT showed universal absence of aggressive features but characteristic ground-glass attenuation (heterogeneous 54.2%, homogeneous 45.8%) with mean size 7.6 ± 2.3 mm. PET/CT revealed minimal FDG avidity (mean maximum standardized uptake value 1.4 ± 0.4), with 84.6% (11/13) lesions demonstrating no significant uptake. Conclusions Incidental frontal process of the maxilla uptake represents a benign scintigraphic phenomenon evidenced by bone metabolic stability on serial scintigraphy, absence of aggressive CT features with characteristic ground-glass attenuation, and minimal FDG avidity. These findings support imaging surveillance over invasive interventions.