Incidental identification of elastofibroma dorsi in oncologic PET/CT imaging: a retrospective single-center analysis

To evaluate the morphological and metabolic characteristics of incidentally detected elastofibroma dorsi (EFD) on F-18 florodeoksiglukoz (FDG) positron emission tomography/computed tomography (PET/CT) and their longitudinal changes in oncologic patients.

We retrospectively reviewed 42 197 PET/CT scans performed at our institution between January 2019 and September 2023. EFD was incidentally identified in 20 patients (0.05%). Patient demographics, primary malignancy, lesion localization, dimensions, and maximum standardized uptake values (SUV_max) were recorded. Measurements were obtained before treatment and at the next 3‑month follow‑up. Statistical analyses included Mann‑Whitney U, Shapiro-Wilk and Spearman correlation tests; significance was set at p<0.05.

The cohort comprised 17 females (85%) and 3 males (15%) with a median age of 67 years (range, 47-83). Primary diagnoses were breast cancer (n=8, 40%) and various other malignancies (n=12, 60%). Lesions were bilateral in 75% of cases. Pre‑treatment lesion size ranged from 10 to 55 mm; median SUV_max was 2.4 (right) and 2.5 (left). No significant differences in baseline size or SUV_max were observed between breast and other cancers. A moderate correlation existed between right and left SUV_max (r=0.641; p=0.010). After 3 months, only the left longest diameter showed a statistically significant decrease (median, 45.0 mm vs. 43.0 mm; p=0.034), which may reflect measurement variability or positional factors rather than true biological change. SUV_max values remained stable.

Incidentally detected EFD on PET/CT exhibits low to moderate and stable FDG uptake and predominantly bilateral localization. Recognition of its characteristic features can prevent unnecessary interventions.