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Elastofibroma Dorsi: MR and CT findings
European Journal of Radiology 27 (1998) 264 – 267
Case report
Elastofibroma Dorsi: MR and CT findings Rafaela Soler *, Ine´s Requejo, Francisco Pombo, Ana Sa´ez Department of Radiology, Hospital Juan Canalejo, Xubias de arriba, 84, La Corun˜a 15006, Spain Received 12 August 1996; accepted 23 May 1997
Abstract Elastofibroma dorsi is a benign, pseudotumoral soft tissue lesion of the periscapular area. The characteristical findings in magnetic resonance images and computed tomography usually allow the diagnosis and prevent radical surgery. We report the MR and CT findings of elastofibroma dorsi in four women presenting as an elongated soft tissue mass intermingled with fat, between the ribs and the serratus muscle, deep to the inferior angle of the scapula. © 1998 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Elastofibroma; Elastofibroma dorsi; Soft tissue; Masses; Soft tissue; Pseudotumor; Thorax; Neoplasm; Magnetic resonance; Computed tomography
1. Introduction
2. Case report
Elastofibroma dorsi (ED) is an unusual, benign soft tissue pseudotumoral lesion, characterized by the proliferation of fibrous and adipose tissue in the infrascapular region which most frequently affects elderly women. Although it was first considered a rare entity, small subclinical elastofibromas has been found in autopsy series in 24% of females and 11% of males over 55 years old. MR and CT findings reflect the fibrous and fatty nature of the mass. These imaging findings in the typical infrascapular location are so characteristic, that should suggest the diagnosis of ED and, as has been recently reported, biopsy is not mandatory for diagnosis of ED when typical imaging findings are found [1] . We present four cases of ED and describe the CT and MR findings of this pseudotumoral soft tissue lesion; the characteristics of the signal intensity on T1 weighted images after Gd-DTPA injection and STIR sequences are also described and the value of these sequences in the diferential diagnosis is considered.
2.1. Case 1
* Corresponding author. Tel.: +34 81 178000 ext. 11044.
A 66 year-old female was referred for evaluation of a subscapular mass which she first noticed some weeks before. She had no other complaints and was generally healthy. On physical examination a non tender, firm mass was palpated under the left scapula. The tumor was more obvious when the scapula was rotated anteriorly by flexion and abduction of the shoulder. An echography was performed and showed an ill-defined hyperechogenic solid mass, of approximately 7 cm in diameter. An MR examination was then performed with a 0.5 T superconducting magnet (Philips Gyroscan T5). Axial T1-weighted images with the body coil and a field of view of 400 mm were obtained and an elongated soft tissue mass was detected, located between the ribs and the left serratus anterior muscle. Then a T1-weighted pre and post injection of Gd-DTPA, T2-weighted and short tau inversion recovery (STIR) sequences were obtained with a circular surface coil and a 200 mm field of view. The mass was well defined and measured
0720-048X/98/$19.00 © 1998 Elsevier Science Ireland Ltd. All rights reserved. PII S0720-048X(97)00074-0
R. Soler et al. / European Journal of Radiology 27 (1998) 264–267
265
6.6 ×7 ×3 cm. The signal intensity was heterogeneous with the majority of the mass being intermediate (similar to muscle) on T1-weighted images with linear strands of highly hyperintensity signal (similar to subcutaneous fat) (Fig. 1(a)). After injection of Gd-DTPA no significant enhancement of the signal intensity was detected (Fig. 1(b)). On T2 weighted images the mass was moderately hyperintense (related to muscles) persisting the linear images also similar to subcutaneous fat in this sequence. On STIR images the mass was predominantly hyperintense (Fig. 2). The patient denied surgical procedure and during a 2 year clinical follow-up no modification was observed.
2.2. Case 2 A 60-year-old woman consulted because she noted a painless enlarging mass in the right subscapular region. She referred growing of the mass during the previous year. Past medical history was unrelevant except for medular aplasia secondary to chloranphenicol intake years before with complete recovery. On physical examination a non tender mass was palpated deep to the right scapula.
Fig. 2. On axial STIR images an ill-defined hyperintense mass (asterisks) under the left scapula can be seen.
A MR examination was performed and T1-weighted and T2-weighted images were obtained. The mass was oval, situated between the serratus anterior and the ribs 6×6× 1.5 cm, with a well defined lower part whereas the upper portion of the mass was ill defined. The signal intensity was heterogeneous in all sequences with the majority of the mass being similar to adjacent muscles intermingled with linear hyperintense strands. On clinical follow-up during the last 2 years no modification was observed.
2.3. Case 3
Fig. 1. (a) On T1-weighted axial images a mass (arrows) located below the left anterior serratus muscle (asterisks) can be seen with a intermediate signal intensity and linear strands of high signal intensity; (b) after injection of Gd-DTPA no contrast enhancement was detected. Note the external mark to localize the lesion.
A 39 year-old female was referred to our department by the oncology service because in routine revision of a previous melanoma, a painless tumor was palpated under the right scapula. The primitive melanoma located on the left thigh, had been resected 3 years before. The patient had been also treated with interferon because she was HBV and HCV seropositive. On physical examination an 8 cm mass, firm and mobile was palpated. Regional nodes were not enlarged and motion was not limited. A CT examination after injection of contrast material was performed, in order to evaluate metastatic melanoma. A well defined mass in the right chest wall was identified; the mass had a soft tissue density intermingled with hypodense linear images. No other abnormalities were detected (Figs. 2 and 3). On MR examination centered over the mass and performed with a surphace coil, the mass has the typical intermediate signal intensity in spin-echo T1 and T2-weighted images with central areas of fat signal intensity (Fig. 4). A percutaneous needle-biopsy was performed and microscopic examination was consistent with elastofibroma dorsi.
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R. Soler et al. / European Journal of Radiology 27 (1998) 264–267
Fig. 3. CT scan after contrast injection demonstrated a right subscapular well-defined soft tissue mass (arrowheads) with a density similar to adjacent muscles. Hypodense thin lines related to fat can also be seen.
2.4. Case 4 A 52 year-old right handed woman presented with a painless mass under the right scapula. She incidentally discovered this prominence several months before. Shoulder motion was normal and she was otherwise asymptomatic. Previous medical history was unremarkable. Physical examination confirmed the presence of a mass under the right scapula. A CT scan without IV contrast material revealed an ill defined mass, measuring 4 ×5 ×2 cm, inferior to the distal tip of the right scapula, with attenuation values similar to those of the neighboring muscles and lineal hypodense areas interspersed, suggesting fatty streaks within the mass. The patient was lost to follow-up.
3. Discussion The term elastofibroma dorsi was proposed by Jarvi and Saxen to describe a benign non-neoplasic proliferation of fibrous tissue of the periscapular region. Elastofibroma dorsi is usually found as an oval soft tissue mass in the subscapular area, bordered by the subscapularis, rhomboid, latissimus dorsi and serratus anterior muscles. Although this is the most frequent location, elastofibroma affecting other locations such as the hand, foot, greater trochanter, ischial tuberosity, olecranon, cervical epidural space, bulbar conjunctive and stomach have also been reported [2]. Elastofibroma dorsi is usually asymptomatic and discovered incidentally by the patient, who notes the mass, protuding in the scapular region. Ocasionally the patients can refer stiffness, pain and/or limited motion of the shoulder. The size of the mass varies
Fig. 4. On axial T2-weighted images at a lower level than Fig. 3 the mass (arrows) has low to intermediate signal intensity. The linear central strands are similar to subcutaneous fat.
from a few cm to 15–20 cm and can remain stable or grow slowly. ED is typically found in elderly females (females/males: 13/1), although cases in children and teenagers have been reported [2,3]. There is a right side predominance but bilaterality has been reported in up to 66% of the cases [4–7]. Histologically ED is composed by hyalinized collagen, fibroblasts and mature adipose tissue. The pathogenesis of the ED has been related to a repeated mechanical friction between the chest wall and the scapula and in fact many patients have a past occupational history of heavy manual labor. However, a familial tendency in as many as one-third of cases suggests a genetic predisposition in the pathogenesis of this proliferative disorder [2], and recent studies suggest an abnormal elastogenesis rather than a degeneration of the preexisting elastic fibers as the main pathogenetic factor. Imaging examination are usually performed in patients with chest wall masses to establish a diagnosis and to evaluate anatomic extension previous to surgery. Besides this, ED can be found in CT or MR thoracic examination performed for unrelated reason. On CT and MR examination, ED is a non-encapsulated mass, with variably-defined borders, and a lenticular form with its long axis in craniocaudal orientation. It shows an heterogeneous soft-tissue attenuation, mostly similar to the skeletal muscles, with linear interlaced low density streaks suggesting mature fat. The fibrous and fatty composition is usually well reflected on T1 and T2-weighted images. A predominance of areas of intermediate signal on T1-weighted images and relatively low signal intensity (slightly higher than muscles) on T2-weighted images due to dense fibrous connective tissue can be seen mixing with linear strands which have a signal intensity similar to that of subcutaneous fat, due to the adipose interspersed elements [1,3,4,7–10].
R. Soler et al. / European Journal of Radiology 27 (1998) 264–267
The signal intensity modification after Gd-DTPA injection and the findings on STIR sequences are nowadays considered an important tool in the detection and differential diagnosis of soft tissue lesions. The signal intensity of ED on T1-weighted sequences after paramagnetic contrast injection has been reported in a few cases as diffuse or heterogeneous enhancement [1,4]. In our case, ED shows no contrast enhancement after Gd-DTPA injection. The variability of ED after GdDTPA injection makes contrast enhanced images not useful to establish a differential diagnosis between ED and other soft tissue lesions. ED has been previously reported in one case as poorly defined inhomogeneous mass on STIR sequences [4], whereas in our case ED showed a homogeneous hyperintense ill-defined soft tissue lesion (Fig. 2). ED is easily diagnosed by CT or MR when it has the typical appearance with linear mature fat within the mass. However, atypical ED can be seen with a homogenenos soft tissue appearance due to lesions with less amount of fatty tissue. Differential diagnosis with other soft-tissue masses should be established in atypical ED. The hallmark in differential diagnosis is the relative hypointensity on T2-weighted images of ED, so the differential diagnosis should be established with relatively acellular tumors or with large amounts of collagen such as desmoid and with soft tissue lesions containing hemosiderin such as giant cell tumors of tendon sheath [11,12]. The use of Gd-DTPA injection do not afford additional information because ED and desmoid tumor had both variable enhancement [12]. STIR images are very useful in the diagnosis of soft tissue lesions characterized by the presence of mature fat because its characteristic supression of fat signal intensity. However, the additional effect of T1 and T2 relaxation times and the scarcy amount of fat in ED makes that variable homogeneous or heterogeneous signal intensity can be seen in this lesion. So, we believe that STIR sequences are not useful in the characterization of ED. Surgical removal is indicated in large masses of ED, when symptoms are present or for stetical reasons. Only a few cases of local recurrence have been reported after incomplete resection [2]. In summary, ED previously considered a rare benign tumor, based on data of autopsy series is probably more frecuent than previously believed. With the increasing use of radiologic imaging procedures, many of these lesions will be incidentally dicovered. A correct diagnosis and a proper clinical attitude is necesary for an otherwise nonworrisome proliferative disorder. Its
.
267
typical appearance on CT and MR as a soft tissue mass similar to adjacent muscles interpersed with linear strands of fat in a characteristic location usually allows the correct diagnosis, avoiding more agressive procedure. Appendix A. Addendum Since the submission of the first manuscript we have seen another patient with typical CT and MR imaging findings of elastofubroma dorsi. The patient, a 55 yearold woman, was being examined by CT because an unrelated condition and a well defined oval mass under the right scapula was identified, with its greater diameter of 3 cm. The mass had a density similar to the neighbouring soft tissue of the chest wall, intermingled with linear fatty densities in a MR examination the mass had a signal intensity similar to the muscles in T1 and T2 weighted spin-echo sequences intermingled with linear strand with a signal similar to subcutaneous fat. The mass was painless and the patient was informed about the diagnosis of the incidental finding and denied biopsy or surgical procedure. References [1] Yu JS, Weis LD, Vaughan LM. MRI of elastofibroma dorsi. J Comput Assist Tomogr 1995;19:601 – 3. [2] Nagamine N, Nohara Y, Ito E. Elastofibroma in Okinawa a clinicopathologic study of l70 cases. Cancer 1982;50:1794–805. [3] Devaney D, Livesley P, Shaw D. Elastofibroma dorsi:MRI diagnosis in a young girl. Pediatr Radiol 1995;25:282 – 3. [4] Kransdorf MJ, Meis JM, Montgomery E. Elastofibroma dorsi: MR and CT appearance with radiologic-pathologic correlation. AJR 1992;159:575 – 9. [5] Machens H, Mechtersheimer R, Gohring U. Bilateral elastofibroma dorsi. Ann Thorac Surg 1992;54:774 – 6. [6] Bennet KG, Organ CH, Cook S. Bilateral elastofibroma dorsi. Surgery 1988;103:605 – 7. [7] Gould ES, Javors BR, Morrison J. MR appearance of bilateral periscapular elastofibroma. J Comput Assist Tomogr 1989;13:701 – 3. [8] Vande Berg B, Malghem J, Leflot JL. Case report: Elastofibroma dorsi: a pseudomalignant lesion. Clin Radiol 1996;51:67–9. [9] Massengill AD, Sundaram M, Kathol MH. Elastofibroma dorsi: a radiological diagnosis. Skeletal Radiol 1993;22:121 – 3. [10] Marin ML, Austin JHM, Markowitz AM. Elastofibroma dorsi: CT demonstration. J Comput Assist Tomogr 1987;11:675–7. [11] Sundaram M, McGuire MH, Schajowicz. Soft tissue masses: histologic basis for decreased signal (short T2) on T2-weighted MR images. AJR 1987;148:1247 – 50. [12] Romero JA, Kim EE, Kimm CG, Chung WK, Isiklar I. Different biologic features of desmoid tumors in adult and juvenile patients. MR demonstration J Comput Assit Tomogr 1995;19:782 – 7.
Case report
Elastofibroma Dorsi: MR and CT findings Rafaela Soler *, Ine´s Requejo, Francisco Pombo, Ana Sa´ez Department of Radiology, Hospital Juan Canalejo, Xubias de arriba, 84, La Corun˜a 15006, Spain Received 12 August 1996; accepted 23 May 1997
Abstract Elastofibroma dorsi is a benign, pseudotumoral soft tissue lesion of the periscapular area. The characteristical findings in magnetic resonance images and computed tomography usually allow the diagnosis and prevent radical surgery. We report the MR and CT findings of elastofibroma dorsi in four women presenting as an elongated soft tissue mass intermingled with fat, between the ribs and the serratus muscle, deep to the inferior angle of the scapula. © 1998 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Elastofibroma; Elastofibroma dorsi; Soft tissue; Masses; Soft tissue; Pseudotumor; Thorax; Neoplasm; Magnetic resonance; Computed tomography
1. Introduction
2. Case report
Elastofibroma dorsi (ED) is an unusual, benign soft tissue pseudotumoral lesion, characterized by the proliferation of fibrous and adipose tissue in the infrascapular region which most frequently affects elderly women. Although it was first considered a rare entity, small subclinical elastofibromas has been found in autopsy series in 24% of females and 11% of males over 55 years old. MR and CT findings reflect the fibrous and fatty nature of the mass. These imaging findings in the typical infrascapular location are so characteristic, that should suggest the diagnosis of ED and, as has been recently reported, biopsy is not mandatory for diagnosis of ED when typical imaging findings are found [1] . We present four cases of ED and describe the CT and MR findings of this pseudotumoral soft tissue lesion; the characteristics of the signal intensity on T1 weighted images after Gd-DTPA injection and STIR sequences are also described and the value of these sequences in the diferential diagnosis is considered.
2.1. Case 1
* Corresponding author. Tel.: +34 81 178000 ext. 11044.
A 66 year-old female was referred for evaluation of a subscapular mass which she first noticed some weeks before. She had no other complaints and was generally healthy. On physical examination a non tender, firm mass was palpated under the left scapula. The tumor was more obvious when the scapula was rotated anteriorly by flexion and abduction of the shoulder. An echography was performed and showed an ill-defined hyperechogenic solid mass, of approximately 7 cm in diameter. An MR examination was then performed with a 0.5 T superconducting magnet (Philips Gyroscan T5). Axial T1-weighted images with the body coil and a field of view of 400 mm were obtained and an elongated soft tissue mass was detected, located between the ribs and the left serratus anterior muscle. Then a T1-weighted pre and post injection of Gd-DTPA, T2-weighted and short tau inversion recovery (STIR) sequences were obtained with a circular surface coil and a 200 mm field of view. The mass was well defined and measured
0720-048X/98/$19.00 © 1998 Elsevier Science Ireland Ltd. All rights reserved. PII S0720-048X(97)00074-0
R. Soler et al. / European Journal of Radiology 27 (1998) 264–267
265
6.6 ×7 ×3 cm. The signal intensity was heterogeneous with the majority of the mass being intermediate (similar to muscle) on T1-weighted images with linear strands of highly hyperintensity signal (similar to subcutaneous fat) (Fig. 1(a)). After injection of Gd-DTPA no significant enhancement of the signal intensity was detected (Fig. 1(b)). On T2 weighted images the mass was moderately hyperintense (related to muscles) persisting the linear images also similar to subcutaneous fat in this sequence. On STIR images the mass was predominantly hyperintense (Fig. 2). The patient denied surgical procedure and during a 2 year clinical follow-up no modification was observed.
2.2. Case 2 A 60-year-old woman consulted because she noted a painless enlarging mass in the right subscapular region. She referred growing of the mass during the previous year. Past medical history was unrelevant except for medular aplasia secondary to chloranphenicol intake years before with complete recovery. On physical examination a non tender mass was palpated deep to the right scapula.
Fig. 2. On axial STIR images an ill-defined hyperintense mass (asterisks) under the left scapula can be seen.
A MR examination was performed and T1-weighted and T2-weighted images were obtained. The mass was oval, situated between the serratus anterior and the ribs 6×6× 1.5 cm, with a well defined lower part whereas the upper portion of the mass was ill defined. The signal intensity was heterogeneous in all sequences with the majority of the mass being similar to adjacent muscles intermingled with linear hyperintense strands. On clinical follow-up during the last 2 years no modification was observed.
2.3. Case 3
Fig. 1. (a) On T1-weighted axial images a mass (arrows) located below the left anterior serratus muscle (asterisks) can be seen with a intermediate signal intensity and linear strands of high signal intensity; (b) after injection of Gd-DTPA no contrast enhancement was detected. Note the external mark to localize the lesion.
A 39 year-old female was referred to our department by the oncology service because in routine revision of a previous melanoma, a painless tumor was palpated under the right scapula. The primitive melanoma located on the left thigh, had been resected 3 years before. The patient had been also treated with interferon because she was HBV and HCV seropositive. On physical examination an 8 cm mass, firm and mobile was palpated. Regional nodes were not enlarged and motion was not limited. A CT examination after injection of contrast material was performed, in order to evaluate metastatic melanoma. A well defined mass in the right chest wall was identified; the mass had a soft tissue density intermingled with hypodense linear images. No other abnormalities were detected (Figs. 2 and 3). On MR examination centered over the mass and performed with a surphace coil, the mass has the typical intermediate signal intensity in spin-echo T1 and T2-weighted images with central areas of fat signal intensity (Fig. 4). A percutaneous needle-biopsy was performed and microscopic examination was consistent with elastofibroma dorsi.
266
R. Soler et al. / European Journal of Radiology 27 (1998) 264–267
Fig. 3. CT scan after contrast injection demonstrated a right subscapular well-defined soft tissue mass (arrowheads) with a density similar to adjacent muscles. Hypodense thin lines related to fat can also be seen.
2.4. Case 4 A 52 year-old right handed woman presented with a painless mass under the right scapula. She incidentally discovered this prominence several months before. Shoulder motion was normal and she was otherwise asymptomatic. Previous medical history was unremarkable. Physical examination confirmed the presence of a mass under the right scapula. A CT scan without IV contrast material revealed an ill defined mass, measuring 4 ×5 ×2 cm, inferior to the distal tip of the right scapula, with attenuation values similar to those of the neighboring muscles and lineal hypodense areas interspersed, suggesting fatty streaks within the mass. The patient was lost to follow-up.
3. Discussion The term elastofibroma dorsi was proposed by Jarvi and Saxen to describe a benign non-neoplasic proliferation of fibrous tissue of the periscapular region. Elastofibroma dorsi is usually found as an oval soft tissue mass in the subscapular area, bordered by the subscapularis, rhomboid, latissimus dorsi and serratus anterior muscles. Although this is the most frequent location, elastofibroma affecting other locations such as the hand, foot, greater trochanter, ischial tuberosity, olecranon, cervical epidural space, bulbar conjunctive and stomach have also been reported [2]. Elastofibroma dorsi is usually asymptomatic and discovered incidentally by the patient, who notes the mass, protuding in the scapular region. Ocasionally the patients can refer stiffness, pain and/or limited motion of the shoulder. The size of the mass varies
Fig. 4. On axial T2-weighted images at a lower level than Fig. 3 the mass (arrows) has low to intermediate signal intensity. The linear central strands are similar to subcutaneous fat.
from a few cm to 15–20 cm and can remain stable or grow slowly. ED is typically found in elderly females (females/males: 13/1), although cases in children and teenagers have been reported [2,3]. There is a right side predominance but bilaterality has been reported in up to 66% of the cases [4–7]. Histologically ED is composed by hyalinized collagen, fibroblasts and mature adipose tissue. The pathogenesis of the ED has been related to a repeated mechanical friction between the chest wall and the scapula and in fact many patients have a past occupational history of heavy manual labor. However, a familial tendency in as many as one-third of cases suggests a genetic predisposition in the pathogenesis of this proliferative disorder [2], and recent studies suggest an abnormal elastogenesis rather than a degeneration of the preexisting elastic fibers as the main pathogenetic factor. Imaging examination are usually performed in patients with chest wall masses to establish a diagnosis and to evaluate anatomic extension previous to surgery. Besides this, ED can be found in CT or MR thoracic examination performed for unrelated reason. On CT and MR examination, ED is a non-encapsulated mass, with variably-defined borders, and a lenticular form with its long axis in craniocaudal orientation. It shows an heterogeneous soft-tissue attenuation, mostly similar to the skeletal muscles, with linear interlaced low density streaks suggesting mature fat. The fibrous and fatty composition is usually well reflected on T1 and T2-weighted images. A predominance of areas of intermediate signal on T1-weighted images and relatively low signal intensity (slightly higher than muscles) on T2-weighted images due to dense fibrous connective tissue can be seen mixing with linear strands which have a signal intensity similar to that of subcutaneous fat, due to the adipose interspersed elements [1,3,4,7–10].
R. Soler et al. / European Journal of Radiology 27 (1998) 264–267
The signal intensity modification after Gd-DTPA injection and the findings on STIR sequences are nowadays considered an important tool in the detection and differential diagnosis of soft tissue lesions. The signal intensity of ED on T1-weighted sequences after paramagnetic contrast injection has been reported in a few cases as diffuse or heterogeneous enhancement [1,4]. In our case, ED shows no contrast enhancement after Gd-DTPA injection. The variability of ED after GdDTPA injection makes contrast enhanced images not useful to establish a differential diagnosis between ED and other soft tissue lesions. ED has been previously reported in one case as poorly defined inhomogeneous mass on STIR sequences [4], whereas in our case ED showed a homogeneous hyperintense ill-defined soft tissue lesion (Fig. 2). ED is easily diagnosed by CT or MR when it has the typical appearance with linear mature fat within the mass. However, atypical ED can be seen with a homogenenos soft tissue appearance due to lesions with less amount of fatty tissue. Differential diagnosis with other soft-tissue masses should be established in atypical ED. The hallmark in differential diagnosis is the relative hypointensity on T2-weighted images of ED, so the differential diagnosis should be established with relatively acellular tumors or with large amounts of collagen such as desmoid and with soft tissue lesions containing hemosiderin such as giant cell tumors of tendon sheath [11,12]. The use of Gd-DTPA injection do not afford additional information because ED and desmoid tumor had both variable enhancement [12]. STIR images are very useful in the diagnosis of soft tissue lesions characterized by the presence of mature fat because its characteristic supression of fat signal intensity. However, the additional effect of T1 and T2 relaxation times and the scarcy amount of fat in ED makes that variable homogeneous or heterogeneous signal intensity can be seen in this lesion. So, we believe that STIR sequences are not useful in the characterization of ED. Surgical removal is indicated in large masses of ED, when symptoms are present or for stetical reasons. Only a few cases of local recurrence have been reported after incomplete resection [2]. In summary, ED previously considered a rare benign tumor, based on data of autopsy series is probably more frecuent than previously believed. With the increasing use of radiologic imaging procedures, many of these lesions will be incidentally dicovered. A correct diagnosis and a proper clinical attitude is necesary for an otherwise nonworrisome proliferative disorder. Its
.
267
typical appearance on CT and MR as a soft tissue mass similar to adjacent muscles interpersed with linear strands of fat in a characteristic location usually allows the correct diagnosis, avoiding more agressive procedure. Appendix A. Addendum Since the submission of the first manuscript we have seen another patient with typical CT and MR imaging findings of elastofubroma dorsi. The patient, a 55 yearold woman, was being examined by CT because an unrelated condition and a well defined oval mass under the right scapula was identified, with its greater diameter of 3 cm. The mass had a density similar to the neighbouring soft tissue of the chest wall, intermingled with linear fatty densities in a MR examination the mass had a signal intensity similar to the muscles in T1 and T2 weighted spin-echo sequences intermingled with linear strand with a signal similar to subcutaneous fat. The mass was painless and the patient was informed about the diagnosis of the incidental finding and denied biopsy or surgical procedure. References [1] Yu JS, Weis LD, Vaughan LM. MRI of elastofibroma dorsi. J Comput Assist Tomogr 1995;19:601 – 3. [2] Nagamine N, Nohara Y, Ito E. Elastofibroma in Okinawa a clinicopathologic study of l70 cases. Cancer 1982;50:1794–805. [3] Devaney D, Livesley P, Shaw D. Elastofibroma dorsi:MRI diagnosis in a young girl. Pediatr Radiol 1995;25:282 – 3. [4] Kransdorf MJ, Meis JM, Montgomery E. Elastofibroma dorsi: MR and CT appearance with radiologic-pathologic correlation. AJR 1992;159:575 – 9. [5] Machens H, Mechtersheimer R, Gohring U. Bilateral elastofibroma dorsi. Ann Thorac Surg 1992;54:774 – 6. [6] Bennet KG, Organ CH, Cook S. Bilateral elastofibroma dorsi. Surgery 1988;103:605 – 7. [7] Gould ES, Javors BR, Morrison J. MR appearance of bilateral periscapular elastofibroma. J Comput Assist Tomogr 1989;13:701 – 3. [8] Vande Berg B, Malghem J, Leflot JL. Case report: Elastofibroma dorsi: a pseudomalignant lesion. Clin Radiol 1996;51:67–9. [9] Massengill AD, Sundaram M, Kathol MH. Elastofibroma dorsi: a radiological diagnosis. Skeletal Radiol 1993;22:121 – 3. [10] Marin ML, Austin JHM, Markowitz AM. Elastofibroma dorsi: CT demonstration. J Comput Assist Tomogr 1987;11:675–7. [11] Sundaram M, McGuire MH, Schajowicz. Soft tissue masses: histologic basis for decreased signal (short T2) on T2-weighted MR images. AJR 1987;148:1247 – 50. [12] Romero JA, Kim EE, Kimm CG, Chung WK, Isiklar I. Different biologic features of desmoid tumors in adult and juvenile patients. MR demonstration J Comput Assit Tomogr 1995;19:782 – 7.