Multifocal concomitant scapulothoracic and subgluteal-ischiofemoral elastofibromas

To evaluate the frequency, imaging findings, and patient demographics of synchronous elastofibroma dorsi (ED) and pelvic elastofibromas.

Image archives between 2011 and 2021 were retrospectively searched for CT and MRI reports including the keyword "elastofibroma". Patients with concomitant CT and/or MRI of the chest and pelvic regions were included. The greatest thickness and side of ED were noted. Subsequently, pelvic soft tissues were evaluated for a soft tissue mass with similar radiological features to ED. When detected, its location, greatest transverse diameter, and ischiofemoral space widths were noted. Wilcoxon matched-pairs signed-rank and Mann-Whitney U-tests were performed when appropriate. Pearson's correlations were used to assess the association of presence of subgluteal-ischiofemoral elastofibromas (SGIFE) and ED thickness. The model discrimination of ED thickness was evaluated by calculating the AUC of the ROC.

Eighty-eight patients (Male:Female = 8:80) with a mean age of 70.6 (±10.3) years were included. 96.6 % of patients had bilateral ED. 18.2 % of patients (all females) had at least one concomitant SGIFE. Patients with SGIFE had significantly thicker ED (p < 0.001 right; p = 0.049 left). There was a significant positive correlation between the thickness of ED and presence of SGIFE (r = 0.43, p < 0.001 right; r = 0.25, p = 0.019 left). An AUC of 0.781 (p < 0.001, 95 %-CI:0.675-0.887) and 0.659 (p = 0.049, 95 %-CI:0.523-0.794) were revealed regarding the presence of ipsilateral right and left SGIFE, respectively.

Concomitant SGIFE may accompany ED in up to 18.2% of cases, particularly in women with thick ED. Knowledge of this co-occurrence and the described SGIFE characteristics can facilitate correct diagnosis.