Elastofibroma Dorsi: Demographic, Clinical, and Radiological Assessment: A Retrospective Study

Elastofibroma dorsi (ED) is a rare, slow-growing benign soft tissue mass that typically develops beneath the scapula. It often remains asymptomatic and is incidentally discovered during imaging conducted for other reasons. When symptoms do manifest, they are generally mild and associated with shoulder movement. Due to the potential for ED to mimic more serious conditions on imaging, it is crucial to recognize its characteristic features. This study aimed to evaluate the demographic, clinical, and imaging characteristics of ED in a cohort of patients.

This retrospective observational study was conducted using imaging and clinical records archived at a single radiology center. Data were collected from two distinct periods (2013-2016 and 2022-2024) to enhance the study's statistical power and achieve a larger sample size. Scans were included if both the scapular and axillary regions were clearly visible and if complete clinical data were available. Patients with poor image quality, incomplete records, or a history of scapular surgery or malignancy were excluded. Three experienced radiologists independently evaluated the images for predefined features of ED. Cases with disagreement or atypical findings were referred for biopsy. Clinical data, including age, sex, handedness, BMI, symptoms, and occupation, were recorded. Lesion characteristics were quantitatively assessed, and statistical tests were employed to examine associations between clinical variables, lesion features, and interobserver agreement.

The prevalence of ED was 1.1% based on 13,042 imaging records. The majority of patients (69%) were women. The overall mean age ± SD was 62.7 ± 7.3 years, with the highest frequency observed in individuals over 50 years of age. Among right-handed patients, 82% (n=112) had unilateral lesions on the right side, while 75% (n=6) of left-handed patients exhibited unilateral lesions on the left side. A total of 63.3% (n=91) of the patients were asymptomatic, with the prevalence of symptoms significantly higher in women (43.4%) compared to men (22.2%). The overall mean lesion size was 55 × 36 mm, which was significantly larger in the heavy manual labor group (mean area = 3060 mm2, SD=450 mm2, P<0.05). In the subgroup analysis of bilateral lesions, the dominant side demonstrated a significantly larger mean lesion area than the non-dominant side (1536 mm2 vs. 1120 mm2, P<0.05). Furthermore, we found that symptomatic patients also had a markedly higher mean lesion area (2257 mm2 vs. 1705 mm2). The mean ± SD HU of the lesions was 33 ± 4.1 (range, 19-48), compared to 46 ± 3.7 (range, 35-55) for the adjacent muscle.

Elastofibroma dorsi is more prevalent among women. Most patients remain asymptomatic, and the majority of lesions present unilaterally, in accordance with handedness. Occupational physical activity levels were positively correlated with lesion size, and larger lesions were associated with the presence of symptoms. In bilateral cases, the lesion on the dominant side exhibited greater dimensions than that on the non-dominant side.