Elastofibroma Dorsi

Clinical History

Authors present a sixty year old female with a slow going painful scapular mass. Ultrasound showed a solid lesion that underwent evaluation with CT and MR. These techniques depicted a lenticular lesion located between the ribs, the serratus anterior and the rhomboid with strands of adipose tissue within it.

Imaging Findings

Our patient was a 60 year old woman with a slow going painful scapular mass. Thoracic X-ray with oblique view suggested the presence of a mass between the ribs and the scapula, without osseous destruction or matrix (Fig 1). Ultrasound showed a solid ovoid lesion, echogenic and homogeneous, measuring 5,3x 4,8x 2,2 cm (Fig 2). CT depicted lesion in the right scapular region, located between the ribs, the serratus anterior and the rhomboid, with strands of adipose tissue within it. Another lesion with the same structural characteristics, but smaller dimensions, was also identified in the left scapular area (Fig 3). MR was performed with T1 and T2 weighted sequences, with and without fat suppression, directed to the right scapular region. Images showed that the lesion was composed by soft tissue with intermediate signal and interlaced areas of signal intensity similar to the fat (Fig 4,5,6). Surgical excision was done and the pathologist confirmed the radiological hypothesis of Elastofibroma

Discussion

Elastofibroma is a benign, tumorlike lesion more frequent in adult women. It’s a reactive lesion that usually arises between the inferior margin of the scapula and the posterior chest wall. This lesion has also been reported in infraolecranon region, ischial tuberosity, and over de great trocanter. Bilateral elastofibromas are not uncommon, occurring in 25% of the cases. Symptoms are usually pain and tumefaction [1, 2]. Chest radiographs may show a soft tissue mass overlying the ribs and elevating the lower end of the scapula. At US, elastofibroma dorsi has a peculiar multilayered appearance created by interspersed linear and curvilinear hypoechoic strands (fatty tissue) against an echogenic background (the fibroelastic bulk of the mass) [3]. CT depicts a lenticular mass in the typical localization, most of times with ill defined borders and linear low density streaking [4]. The lesion shows intermediate signal intensity on both T1 and T2 sequences, with interlaced areas of signal intensity similar to that of fat. Although these features are not pathognomonic, their presence in a subscapular lesion in an older patient suggests a presumptive diagnosis of elastofibroma [4, 5]. Differential diagnosis includes hemangioma, fibrosarcoma, liposarcoma, synovial sarcoma, desmoids and fibromatosis, At microscopy, the lesion consists primary of collagen and elastic fibers, scattered fibroblasts, and occasional lobules of adipose tissue [1, 2]. A unique histologic feature is the presence of enlarged, irregular, serrated elastic fibers that are hypereosinophilic [1, 2]. No treatment is necessary in asymptomatic lesions. In symptomatic patients excision is indicated. Local recurrence may occur when excision is incomplete. There no risk of malignant transformation [4,5]

Differential Diagnosis List

Final Diagnosis

Elastofibroma Dorsi

URL:	https://www.eurorad.org/case/5049
DOI:	10.1594/EURORAD/CASE.5049
ISSN:	1563-4086