Case Report
Australasian Radiology (2007) 51, B95–B97
Fig. 3. CT features of bilateral elastofibromas (arrows) in characteristic location between the rib cage and the inferior pole of the scapula. A layered pattern with streaks having the density of fat is visible at the periphery of the masses.
Fig. 1. The appearance of elastofibroma on sonography. Transverse view shows the heterogeneous mass with interspersed linear echoes similar to that of skeletal muscle (arrows).
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Fig. 2. (a) MRI, coronal section T1-weighted image: masses on the lateral aspect of the chest wall whose signal intensity is isointense to muscle on T1-weighted image (arrows), with interspersed lines of high signal on T1-weighted image consistent with fat (arrows). (b) MRI, T2-weighted image: masses on the lateral aspect of the chest wall whose signal intensity is isointense to muscle on T2-weighted image, with interspersed lines of intermediate signal on T2-weighted image consistent with fat (arrows).
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Fig. 4. (a) The appearance of elastofibroma on sagittal T1-weighted MRI. The mass is typically located at the inferior pole of the scapula (S), deep to the serratus anterior (SA) muscle. (b) Axial T2weighted MRI demonstrates masses at the posterolateral aspect of the chest wall with signal intensity similar to that of muscle interspersed with intermediate signal intensity compatible with the presence of fat. © 2007 The Authors Journal compilation © 2007 Royal Australian and New Zealand College of Radiologists
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B96
R HAYKIR ET AL.
Elastofibroma dorsi: Typical radiological features R Haykir, S Karakose and A Karabacakoglu Department of Radiology, Meram Medical Faculty, Selcuk University, Konya, Turkey
SUMMARY Elastofibroma dorsi is a rare benign and slow-growing fibro-proliferative lesion. It has a characteristic location (periscapular region) and a specific imaging appearance (sonography, CT, MRI) allowing accurate prospective diagnosis. The recognition of this benign lesion avoids unnecessary biopsy and/or surgery. We report two cases of bilateral elastofibroma dorsi illustrating characteristic imaging features on ultrasound, CT and MRI. Key words: CT, elastofibroma dorsi; MRI; ultrasound.
INTRODUCTION Elastofibroma is a rare, slow-growing soft tissue tumour that is characterized by thick elastic fibres in a background rich in collagen and fat. Recognition of the lesion is important as the differential diagnosis must be supplied with other benign and malignant tumours. The CT and MRI appearances are often typical as they show the characteristic layered pattern of fatty tissue (low density by CT, high signal on T1-weighted images and intermediate signal on T2-weighted images by MRI) and fibrous tissue (similar to muscle in terms of density by CT and signal intensity by MRI).1,2 The characteristic findings on MRI and CT usually allow the diagnosis to be made, thus preventing radical surgery. Ultrasound may also contribute to the diagnosis. We report two cases of bilateral elastofibroma dorsi with characteristic findings on ultrasound, CT and MRI.
CASE REPORT Case 1 A 50-year-old woman, previously fit and healthy, was referred to our outpatient clinic with a 2-year history of posterolateral chest wall pain. Over the preceding 4 months, the patient had noticed a swelling below the inferior angle of the left scapula. Sonography was showed an abnormal mass of tissue in a location at the inferior pole of left scapula (Fig. 1). Magnetic resonance imaging was performed using a 1.5 T unit (Edge, Picker, USA) with the patient supine position on the body coil. Axial, sagittal and coronal T1-weighted spin-echo and T2-weighted spin-echo images were performed. Magnetic resonance imaging revealed masses on the posterolateral aspect of the chest wall bilaterally. Signal intensity was intermediate and similar to that of muscle on T1- and T2-weighted images. There were interspersed lines of high signal on T1-weighted images and intermediate signal on T2-weighted images consistent with fat (Fig. 2). The diagnosis of elastofibroma was readily made by examination of T1- and T2-weighted images. An excision biopsy was performed.
Case 2 A 65-year-old man was admitted to our hospital with severe pain and swelling at the inferior pole of both scapulae. On palpation,
the masses were not tender and not fixed to underlying structures. He was referred to us by his clinician for CT examination to evaluate the masses. Computed tomography showed soft tissue masses with poorly defined margins and attenuation similar to that of skeletal muscle. A layered pattern with streaks having the density of fat was visible at the periphery of the masses (Fig. 3). Magnetic resonance imaging showed heterogeneous soft tissue masses, with a signal intensity similar to that of skeletal muscle interlaced with strands of fat. The masses were deep to serratus anterior at the lower pole of the scapula (Fig. 4). The diagnosis of elastofibroma was readily made by examination of MRI. Surgery was performed because the patient had severe pain and was distressed by ‘clunking’ of the shoulder. Histopathological examination confirmed the diagnosis of elastofibroma.
DISCUSSION Elastofibroma is a slow-growing fibroelastic pseudotumour thought to result from mechanical friction between the scapula and chest wall; hence it is to be considered reactive rather than neoplastic. This lesion was first reported in 1961 by Jarvi and Saxen.3 The prevalence of elastofibroma was 2% in a series of individuals older than 60 years of age who underwent CT of the chest to investigate lung disease.4 The tumour is usually unilateral, although bilateral involvement has been reported in 10–66% of cases. Trauma, mechanical stress and chronic irritation have also been suggested as aetiological factors, but these factors alone may not explain the development of elastofibroma. Elastofibroma occurs chiefly in older individuals between 49 and 71 years.5 The lesion occurs more frequently in women with a slight right-sided preponderance. This lesion was initially described as elastofibroma dorsi because of its typical location in the subscapular and infrascapular regions. Most do occur in the lower periscapular region, at approximately the sixth through eighth ribs, and deep to the serratus anterior, latissimus dorsi and rhomboideus major muscles,3,5 but cases have also been reported in the neck, foot, hand, thigh and deltoid muscle.6–8 The lesions are asymptomatic in more than 50% of the cases. When symptoms are present, they are usually mild, con-
R Haykir MD; S Karakose MD; A Karabacakoglu MD. Correspondence: Dr Rahime Haykir, Department of Radiology, Meram Medical Faculty, Selcuk University, Konya 42080, Turkey. Email:
[email protected] Submitted 5 June 2006; accepted 28 July 2006. doi: 10.1111/j.1440-1673.2007.01786.x © 2007 The Authors Journal compilation © 2007 Royal Australian and New Zealand College of Radiologists
ELASTOFIBROMA DORSI sisting of a swelling, clunking of the scapula on moving the shoulder, or moderate pain; severe pain is uncommon. Malignant transformation and recurrence has not been reported.5 Various modalities have been used in the evaluation of elastofibroma and its features on imaging have been described. Magnetic resonance imaging is the best non-invasive technique and most useful for diagnosis. Elastofibromas appear as poorly circumscribed soft tissue lesions with similar signal intensity to that of skeletal muscle. The margins may be sharp or indistinct and the mass itself is heterogeneous. On T1- and T2-weighted sequences, the fibrous tissue produces low-intensity signal nearly identical to that generated by the muscle. The foci of fatty tissue are seen as high signal on T1-weighted sequences and as intermediate signal on T2-weighted images. In the most typical pattern, streaks of fatty tissue alternate with strands of fibrous tissue, forming straight or curved lines that are roughly parallel to the chest wall. Postgadolinium enhancement is described as ranging from subtle to moderate or marked.9,10 Thus, the diagnosis is readily made by evaluation of T1- and T2weighted images, provided the radiologist is familiar with the features of elastofibroma. Computed tomography usually shows a heterogeneous soft tissue mass with attenuation similar to that of skeletal muscle poorly defined margins. Computed tomography is less sensitive than MRI for visualizing the streaks of fatty tissue. In this situation, CT does not provide the definitive diagnosis.11 The location is highly suggestive, however, particularly when there is a bilateral distribution. Ultrasonography shows an abnormal mass of tissue in a location typical for elastofibroma. Typically, an alternating pattern of hyperechoic and hypoechoic lines that are roughly parallel to the chest wall is seen in all or part of the mass. Plain radiographs may be normal or may show soft tissue density in the periscapular region when the scapula is raised.12 There is considerable disagrement about the need for obtaining biopsy. The authors of early studies recommended routine biopsy to rule out sarcoma. On the contrary, most of the recent publications indicate that imaging findings are sufficiently typical as to make a biopsy unnecessary.13,14 The diagnosis of elastofibroma is readily established by typical anatomical location at the lower pole of the scapula and the clinical symptom of a scapular clunk as the arm is abducted or adducted. Thus, the definitive diagnosis can be made by MRI (the investigation of choice), CT or even ultrasonography. A bilateral distribution is an additional argument in favour of elastofbroma. The radiological appearance is characteristic, obviating the need for a biopsy. In cases where the patient is asymptomatic, excision is usually unnecessary. In symptomatic cases local excision is the best treatment.
REFERENCES 1. Yavuzer R, Ozmen S, Cavusoglu T, Poyraz A, Suer O. Elastofibroma dorsi. Ann Plast Surg 2000; 45: 340–1. 2. Malghem J, Baudrez V, Lecouvet F, Lebon C, Maldague B, Vande Berg B. Imaging study findings in elastofibroma dorsi. Joint Bone Spine 2004; 71: 536–41. 3. Jarvi OH, Saxen AE. Elastofibroma dorsi. Acta Pathol Microbiol Scand 1961; 144: 83–4. 4. Brandser EA, Goree JC, El-Khoury GY. Elastofibroma dorsi: prevalence in an elderly patient population as revealed by CT. AJR 1998; 171: 977–80. 5. Nagamine N, Nohara Y, Ito E. Elastofibroma in Okinawa. A clinicopathologic study of 170 cases. Cancer 1982; 50: 1794– 805. © 2007 The Authors Journal compilation © 2007 Royal Australian and New Zealand College of Radiologists
B97 6. Maldjian C, Adam RJ, Maldjian JA, Rudelli R, Bonakdarpour A. Elastofibroma of the neck. Skeletal Radiol 2000; 29: 109–11. 7. McPherson FC, Norman LS, Truitt CA, Morgan MB. Elastofibroma of the foot: uncommon presentation: a case report and review of the literature. Foot Ankle Int 2000; 21: 775–7. 8. Mirra JM, Straub LR, Jarvi OH. Elastofibroma of the deltoid. A case report. Cancer 1974; 33: 234–8. 9. Schick S, Zembsch A, Gahleitner A et al. A typical appearance of elastofibroma dorsi on MRI: case reports and review of the literature. J Comput Assist Tomogr 2000; 24: 288–92. 10. Zembsch A, Schick S, Trattnig S, Walter J, Amann G, Ritschl P. Elastofibroma dorsi. Study of two cases and magnetic resonance imaging findings. Clin Orthop Relat Res 1999; 364: 213–19. 11. Kransdorf MJ, Meis JM, Montgomery E. Elastofibroma: MR and CT appearance with radiologic–pathologic correlation. AJR 1992; 159: 575–9. 12. Baudrez V, Malghem J, Van de Berg B, Lebon C, Lecouvet F, Maldague B. Ultrasonography of dorsal elastofibroma. Apropos of 6 cases. J Radiol 1998; 79: 549–51. 13. Nishida A, Uetani M, Okimoto T, Hayashi K, Hirano T. Bilateral elastofibroma of the thighs with concomitant subscapular lesions. Skeletal Radiol 2003; 32: 116–18. 14. Fuchs A, Henrot P, Walter F et al. Lipomatous tumors of soft tissues in the extremities and the waist in adults. J Radiol 2002; 83: 1035–57.
