Elastofibroma is often observed beyond the sixth decade of life [4, 5]. Although extremely rare, it has also been reported in children and in infants [6, 7]. This tumor has female predilection. Nagamine et al. studied 170 cases of elastofibroma, of which only 12 cases were in males .
The classic site of elastofibroma is the scapular region between the sixth and the eighth ribs and the inferior angle of the scapula, beneath the serratus anterior, latissimus dorsi, and levator scapulae muscles . It is more frequently observed on the right side, but bilateral lesions are common [5, 8]. Rarely, elastofibroma may occur in different anatomic locations causing diagnostic difficulties, including the deltoid muscle, thoracic wall, gluteal and inguinal region, axilla, hand, foot, elbow, orbit and some visceral organs such as stomach, omentum and rectum [9, 10]. The size of elastofibroma varies. In their cohort of 61 cases of elastofibroma, Deveci et al. have reported that the average diameter of the elastofibroma was 8.7 cm .
Besides concomitant infrascapular and infra-olecranon elastofibromas, multiple elastofibromas are uncommon with few cases reported in the English medical literature . Nagamine et al. reported a cases of infrascapular elastofibroma with involvement of ischial tuberosity . Hassouna et al. reported a case of triple elastofibromas with one in the usual infrascapular region and the other two in the unusual suprascapular region . Olchowy et al. reported a similar case of triple elastofibromas with MRI documentation . Nishida et al. reported a case of elastofibroma that occurred in both thighs and infrascapular regions . Cevolani et al. reported a case of bilateral elastofibroma in the gluteal region . To our knowledge, concomitant bilateral elastofibroma in the scapular and gluteal regions has not been reported previously.
Different environmental and genetic explanations have been postulated to explain the development of elastofibroma; however, the exact pathogenesis remains unclear. It has been suggested that elastofibroma develops due to repetitive mechanical trauma, which induces reactive hyperproliferation and degeneration of fibroelastic tissue . The advanced age of patients with elastofibroma, the higher frequency among manual workers, and the right-hand side predominance support this theory. However, previous studies have also reported that elastofibromas occur in areas exposed to limited mechanical friction and that they can occur in both the dominant and non-dominant sides. Because of these discrepancies, the mechanical theory is insufficient to explain the development of elastofibroma. Giebel et al. have proposed vascular insufficiency as the cause for the degenerative changes . It has been suggested that elastofibroma originates via a very slow neoplastic process; some studies have shown that a monoclonal proliferation with genomic instability is involved in elastofibroma development . Genetic predisposition is a possible explanation because family history of elastofibroma has been reported in up to one-third of studied cases [5, 19]. Elastofibroma has a multifactorial etiology as no single theory has provided an explanation for all cases.
In most cases, elastofibroma is asymptomatic and is diagnosed incidentally. Few cases may present with palpable masses, discomfort, snapping of the scapula, or functional limitations. Symptoms caused by impingement of the brachial plexus may also be observed .
Imaging is essential and may preclude the need for biopsy, particularly if the lesions occur at their typical locations and have the typical imaging features . Recognition of elastofibroma is important as the differential diagnoses include primary or secondary sarcoma, neurofibroma, desmoid tumors, and malignant histiocytofibroma .
Plain radiographs are usually normal, but they may show a raised scapula or a soft tissue density. Ultrasound shows alternating patterns of hypo- and hyperechoic lines parallel to the chest wall with no significant vascular flow on Color Doppler . CT scans show a non-encapsulated heterogenous soft tissue mass with a density similar to that of skeletal muscles with possible infiltrating hypodense areas representing fat. MRI demonstrates a lenticular-shaped mass with intermediate signal intensity, similar to that of skeletal muscles, on both T1- and T2-weighted images. Linear strands of high signal intensity are seen reflecting the histological composition of adipose tissues within the fibrous mass that suppress in signal on the fat saturated sequences. Although CT and MRI can readily make the diagnosis, avid contrast enhancement or marked dominance of adipose tissue may result in false diagnosis . Positron emission tomography frequently demonstrates mild to moderate uptake of fluorodeoxyglucose . This uptake is related to high vascularity, fibroelastic proliferation, and inflammatory process within the mass. If imaging appearance was atypical or there is any doubt on the diagnosis, either close follow up imaging or biopsy are reasonable recommendations . Although the imaging findings in the present case were typical for elastofibroma, a biopsy was done considering the patient’s anxiety.
Because elastofibroma is an incidental finding in most cases, surgical treatment is often not required and regular follow-up is not needed as malignant transformation has not been previously reported . Complete surgical excision is advised only for symptomatic cases or for cosmetic concerns . Hematoma formation is a possible post-operative complication because of the high vascularity of the periscapular region . Wide and radical resections should be avoided as marginal resection is sufficient . Surgery is curative and local recurrence is unusual and was attributed due to incomplete excision as the borders of the lesion are often indistinct .
This report describes a rare case of multiple elastofibromas and its typical imaging features; our findings demonstrate that elastofibromas are not exclusive to the periscapular region.