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Subscapular elastofibroma: A reactive pseudotumor
Subscapular elastofibroma: A reactive pseudotumor Tom Nielsen, MD, Otto Sneppen, MD, Olaf Myhre-Jensen, MD, Soren Daugaard, MD, and Jens N~rbaek, MD, Aarhus and Copenhagen, Denmark Six cases of elastofibroma located in the subscapular region are reported. The age of the patients ranged from 45 to 71 years (mean 59.5 years). In three cases the symptoms were posterior shoulder pain with arm motion, and one of these also had a snapping scapula. Two cases had tumor prominence as the only symptom, and in one case the tumor was found accidentally while thoracotomy was being performed. On magnetic resonance imaging a nonencapsulated soft-tissue mass closely related to the thoracic wall and elevating the scapula was identified. At surgery the tumor was densely adherent to the periosteum of the ribs and the external fascia of the rib cage, and peripherally it proceeded into the loose connective tissue of the subscapular space. Local excision was performed. At follow-up 1 to 8 years after surgery no recurrence was observed, and all patients with painful lesions had complete relief of pain. (J SHOULDERELBOWSURG 1996;5:209-13.)
E lastofibroma is a rare soft-tissue pseudotumor forming a soft-tissue mass. It nearly always is located in the inferior part of the thoracoscapular space, where it elevates the inferior angle of the scapula ~e, 12, 19 Pathologically it is a firm and rubbery fibro-fatty mass without a defined capsule. It often contains several cysts. On microscopy the lesion is characterized by the presence of irregular, fragmented elastic fibers, distinguishing the elastofibroma from other fibrous pseudotumors and neoplasms. 8' 12, 182o At surgery the tumor is often closely adherent to the intercostal ligaments and periosteum of the ribs, and superficially it is closely related to the serratus anterior muscle and the inferior angle of the scapula. When the arm and scapula are in neutral position, the tumor lies under the inferior angle of the scapula, and a prominence of the inferior scapula is seen. When the arm is elevated, the inferior part of the scapula is displaced forward, and the tumor prominence becomes visible. From the Shoulder and Elbow Clinic, UniversiV Hospital of Aarhus, and the Centres for Bone and Soft Tissue Tumors, University Hospital of Aarhus and State Universily Hospital of Copenhagen. Reprint requests: Tom Nielsen, MD, Shoulder and Elbow Clinic, University Hospital of Aarhus, Randersvej 1, 8200 Aarhus N, Denmark. Copyright @ 1996 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/96/$5.00 + 0 3211169101
Thus the lesion interferes with the scapular-thoracic function and may cause shoulder pain and a snapping scapula. In rare cases it may also cause a slight reduction in shoulder motion. 14 Because the operative findings of the subscapular elastofibroma are similar to those of a sarcoma, it is particularly important to know the benign nature of this lesion to avoid performing unnecessary radical and mutilating excisions. We report six cases of subscapular dastofibroma, focusing on the symptoms and signs especially related to thoracoscapular function. METHODS Six cases of subscapular elastofibroma were diagnosed and treated from 1980 to 1993 at the State University Hospital in Copenhagen and the University Hospital in Aarhus, Denmark. These two centers serve a population of approximately 5 million people. The patients' charts were reviewed for medical history and relevant operative course, and the patients were sent a questionnaire for follow-up. Histologic sections of each case were reviewed to verify the diagnosis. RESULTS The clinical histories and follow-up data are summarized in Table I. Age at the time of diagnosis ranged from 45 to 71 years (average 60 years). Four patients were men, and two were women. 209
210
J. Shoulder Elbow Surg. May/June 1996
Nielsen el al.
Figure 1 Magnetic resonance image of scapular region of patient 1. Encapsulated soft-tissue tumor is seen elevating right scapula (arrows). None of the patients had any history of heavy work, but one (case 3) had worked as a telephonist for 25 years with repetitive movement of the arm in elevated positions. Only one case (2) had a history of trauma, which was a dislocation of the same shoulder 4 years before any tumor symptoms appeared. The tumor mass was the only symptom in two cases. Three cases had posterior shoulder pain during shoulder motion. One of these also had pain at rest, and another had a snapping scapula caused by rubbing of the inferior angle of the scapula on the tumor. Five of the six cases had preoperative physical examination; in all of these the tumor was slightly mobile over the thoracic wall, and superficially the range of scapular motion was normal. Magnetic resonance imaging (MRI) was performed before operation in two cases, and computed tomography was performed in another three. MRI findings indicated a rather well-defined and moderately inhomogenous lesion without any surrounding soft-tissue edema. The tumors were located between the chest wall and the seratus anterior muscle (Figure 1). On Tl-weighted images the lesions had approximately the same signal intensity as skeletal muscle with interspersed linear and curvilinear areas of high-signal intensity. At surgery in all cases but one, the elastofibromas were adherent to the intercostal ligaments and periosteum of the ribs and superficially were closely related to the serratus anterior. In one case a large bursa was found between the serratus
Figure 2 Grossappearance of tumor. Severalcystsare
seen.
muscle and the tumor. The resected specimens consisted of a fibro-fatty mass containing one or more cysts (Figure 2). The size of the specimens varied from 45 cm 3 to 1232 cm 3. Microscopic examination revealed slightly hypocellular fibrous tissue containing variable numbers of wavy fibers. The cells had the appearance of fibroblasts with uniform, ovoid to spindle-shaped nuclei (Figure 3). Mitosis was only rarely seen. Elastic tissue showed variable numbers of irregular and fragmented elastic fibers within the hypocellular fibrous tissue matrix (Figure 4). After incisional biopsy was performed, all patients underwent local excision of the pseudotumor. The tumor was removed by sharp dissection from its attachment to the periosteum of the ribs and intercostal fascia. Because of the nonencapsulated structure, the excisions were intralesional in two cases and marginal in the remaining four. All patients with symptomatic elastofibromas
J. Shoulder Elbow Surg. Volume 5, Number 3
Nielsen et al.
211
Figure 3 Elastofibromashowing slightly hypocellular fibrous tissue containing irregular thick fibers. (Hematoxylin-eosinstain; original magnification x250.)
had complete relief of their pain within a few months after surgery. At follow-up 1 to 8 years after surgery no recurrence has been observed, and all patients with previous symptoms still have complete relief of pain and no restrictions in their range of movement.
DISCUSSION Elastofibromas are rare, with only 350 cases reported in the literature. A total of 170 of these are from one study reporting a special genetic disposition at the Okinawa Island in Japan, ~9 and the remaining information consists of reports of a few cases, 2-5' 8, 9, 14N6, 2 0 with a maximum of 13 cases in two articles, t~ 12 From the Columbian Presbyterian center seven cases of elastofibroma were diagnosed over a lO-year period. ~7 The pseudotumor is nearly always subscapular in location, and very few cases of the tumor in other locations have been reported, including the infraolecranon region, the greater trochanter region, the deltoid muscle, over the ischial tuberosity, the foot, intraspinal, the hand, the orbital area, and the greater omentum.* Histologically elastofibroma is classified as a benign tumorlike lesion of fibrous tissue, and in surgical staging according to Enneking the tumor is benign, stage 1 (latent), or 2 (active). The cause of the pseudotumor is controversial. *References 1, 6, 7, 10, 13, 18, 19, 21.
Figure 4 Elastofibromashowing globules of elastin in
linear arrangement. (Frhof's elastin stain; original magnification x200.)
212
J. ShoulderElbow Surg. May/June 1996
Nielsen et al.
Table I Summary of cases of subscapular dastofibroma Delay from first symptoms to diagnosis
Signs
24 mo
Visible tumor when the arm is elevated
2 mo
Visible tumor when the arm is elevated
Moderate shoulder pain during activity
12 mo
50/M
(Accidentally found during thoracotomy)
None
Visible tumor when the arm is elevated; snapping scapula None
5
45/M
Tumor mass
6 mo
Visible tumor when the arm is elevated
6
68/F
Moderate shoulder pain and tumor mass
4 yr
Visible tumor when the arm is elevated
Case no.
Age (yr)/sex
1
61/M
Tumor mass
2
71/M
Marked subscapular pain
3
62/F
4
Symptoms
M, Male; F, female; MRI, magnetic resonance imaging; CT, computed tomography.
Originally it was thought to be caused by hypertrophy of elastic fibers followed by degeneration and fragmentation. 12' 19 Further understanding of normal elastogenesis has now lead to the opinion that subscapular elastofibroma is a reactive hyperplasia resulting from mechanical friction of the scapula on the chest wall. 12' 15, 18 However, only one study 19 has documented any correlation between heayy work and tumor incidence. All patients are middle-aged or elderly, suggesting a possible degenerative genesis. No clear preference for either sex is evident. One study found a high incidence within the same family line, suggesting genetic disposition, and in fact subscapuFar dastofibroma is bilateral in approximately 10% of the cases, 2' 5. 9, 12, ~6, 19 also suggesting a constitutional influence. An autopsy study showed that 24% of women and 11% of men older than 55 years of age had clinical changes consistent with subscapular elastofibroma. Of these, 46% were bilateral, supporting the theory of constitutional influence, is Because of the history of our patients and the cases described in the literature, we believe that subscapular elastofibroma is a reaction of the fibrous tissue to mechanical stress and friction. The preference for the subscapular area could be explained by the great range of movement in the thoracoscapular articulation and consequently large biomechanical forces acting on the fibrous tissue in this area. The symptoms are not very prominent; often the only symptom is an asymptomatic tumor mass related to the inferior part of the scapula. Sometimes
the only symptom is pain in the posterior part of the shoulder and the scapula, and this pain most often increases with shoulder use. In one of our cases the tumor caused a painful snapping of the scapula. In a few cases the patients may report some stiffness of the shoulder region because of the reduced thoracoscapular motion, but this stiffness is a problem only in overhead work. 1r 19 The signal characteristics on MRI are typical with fibrous tissue and interspersed fatty areas. This factor combined with the location in the scapular area and the benign clinical course makes a one-stage biopsy and surgical procedure preferable in most cases. However, in one of our cases MRI raised suspicion of a malignant fibromatosis, and therefore a twostage procedure was performed. For surgery a posterior approach with release of a portion of the rhomboid muscle from the distal part of scapula gives excellent access to the tumor, especially when the arm is elevated. The tumor mass has ill-defined margins, and an intralesional excision is usually required. The biomechanical aspects of subscapular elastofibroma are interesting. On the thoracic side the tumor is firmly adherent to the intercostal fascia and to the costal periosteum. On the scapular side it seems closely related to the distal part of the serratus anterior muscle and also to the subscapular fascia. On this basis we would expect a rather restricted thoracoscapular motion, but in most instances, including the six cases from our own series,11, 14 the patients had no stiffness, and they had a rather normal range of thoracoscapular motion. If the tumor represents a direct connection
J. Shoulder Elbow Surg. Volume 5, Number 3
Nielsen et al.
Tumor
MRI/CT
Subscapular location
MRI
Distal third of scapula involving chest wall and serratus anterior Distal half of scapula involving chest wall and adherent to serratus anterior Distal third of scapula involving chest wall as well as serratus anterior Distal third of scapula adherent to the chest wall and serratus anterior Distal half of scapula adherent to the chest wall and serratus anterior Distal third of scapula adherent to the chest wall and serratus anterior
MRI CT
CT CT
size (cm)
Treatment
Follow-up (yr)
Intralesional excision
3
14xllx8
Marginal excision
2
10x8x2.5
Marginal excision
1
5x3x2.5
Marginal excision
5
9x7x5
Intralesional excision
4
8x8x4
Marginal excision
8
8x8x4
from the serratus anterior muscle to the chest wall, then the mobility of the scapula would depend only on the biomechanical properties of the tumor. The thickness of the tumor in our series varied from 3 to 7 cm, and of course the elasticity of the rubbery tissue could not allow the normal 6 cm sliding motion of the inferior angle of the scapula to reach a supero-lateral position as it does during normal maximal elevation. The explanation of this phenomenon is that the elastofibroma often develops very slowly over a long period of time, and the highly differentiated tissue seems to adapt to the demands of the thoracoscapular motion. In most cases a loose connective tissue space is found immediately superficial to the tumor, allowing a sliding motion of the scapula, and some cases have a well-defined subscapular bursa. This finding explains why the pseudotumor at physical examination will be only slightly mobile on the thoracic wall, whereas the scapula slides freely over the tumor surface during elevation of the arm. REFERENCES 1. Austin P,Jakobiec FA, Iwarnoto T, Hornblass A. Elastofibroma oculi. Arch Ophthalmd 1983;8:800-2. 2. Benisch B, Peison B, Marquet E, Sobel HJ. Pre-elastofibroma and elastofibroma (the continuum of elastic-producing fibrous turnoursj. A light and dtras~ructurd study. Arn j Ch~ Pathd 1983;80:88-92. 3. Bennett KG, Organ CH, Cook S, Potha J. Bilateral elastofibrima dorsi. Surgery 1988;103:605-7. 4. Bertholy DP, Shulman HS, Miller HA. Elastofibroma chest wall pseudotumor. Radiology 1986;160:341-2. 5. Brown GW. Elastofibroma dorsi: report of ~ o cases and literature review. Wisc Med j 1991;90:2814.
213
6. Cross DL, Mills SE, Kulund DN. Elastofibroma arising in the foot. South Med J 1984;77:1194-6. 7. Enjoji M, Suumiyoshi K, Suwyioshi K. Elastofibromatous lesions of the stomach in a patient with elastofibroma dorsi. AmJ Surg Pathol 1985;9:233-7. 8. Fukuda Y, Miayke H, Masuda Y, Masugi Y. Histogenesis of unique elastinophilic fibers of elastofibroma. Uhrastructural and imrnunohistochemical studies~ Hum Pathol 1987;18: 424-9. 9. Ghiatas AA, Armstrong S, Tio FO. Case report 583. Skeretal Radiol 1989;18:6 ] 9-22. 10. Govoni E, Severi B, Laschi R, Lorenzini P, Baccararini M. Elastofibroma: an in vivo model of abnormal neoelstogenesis. Ultrastruct Pathol 1988;12:327-39. 11. Jarvi OH, Oansimies PH. Subclinical elastofibrorna in the subscapular region in an autopsy series. Acta Pathol Microbiol Scand 1975;83:87-108. 12. Jarvi OH, Saxen E, Hopsu-Havu VK. Elastofibroma: a degeneralive pseudoturnor. Cancer 1969;23:42-63. 13. Kapf PH, Hocken DB, Simpson RHK Elastofibroma of the hand. J Bone Joint Surg Br t987;69B:648-9. 14. Lagae P, Arth A, Dierick E, Achten E, van de Velde E. Elastofibroma dorsi: CT, MR and pathologic study in a new case. J Br Radiol 1992;75:197-201. 15. Lee E, Dlever R, Blanche C. Elastofibroma dorsi. Mt Sinai J Med 51 : 138~40. 16. Machens HG, Mechtersheimer R, Schlag PH. Bilateral elastofibroma dorsi. Ann Thorac Surg 1992;54:774-6. 17. Marin M, Perzin K, Markowitx AM. Elastofibroma dorsi: benign chest wall tumor. J Thorac Cardiovasc Surg 1989; 98:234-8. 18. Mirra JM, Straub LR, Jarvi OH. Elastofibroma of the deltoid. Cancer 1974;33:234-7, 19. Nagamine N, Nogara Y, Ito E. Elastofibroma in Okinawa. A clinicopathologic study of 170 cases. Cancer 1982;50: 1794-805. 20. Nakamura Y, Ohta Y, Itoh S, et ak Elastofibroma dorsi: cytologic, histologic, immunohistochernical and ultrastructural study. Acta Cytol 1992;36:559-62. 21. Prete P, Henbest M, Michalski JP, Porter RW. Intraspinal elastofibroma. A case report. Spine 1983;8:800-2.
E lastofibroma is a rare soft-tissue pseudotumor forming a soft-tissue mass. It nearly always is located in the inferior part of the thoracoscapular space, where it elevates the inferior angle of the scapula ~e, 12, 19 Pathologically it is a firm and rubbery fibro-fatty mass without a defined capsule. It often contains several cysts. On microscopy the lesion is characterized by the presence of irregular, fragmented elastic fibers, distinguishing the elastofibroma from other fibrous pseudotumors and neoplasms. 8' 12, 182o At surgery the tumor is often closely adherent to the intercostal ligaments and periosteum of the ribs, and superficially it is closely related to the serratus anterior muscle and the inferior angle of the scapula. When the arm and scapula are in neutral position, the tumor lies under the inferior angle of the scapula, and a prominence of the inferior scapula is seen. When the arm is elevated, the inferior part of the scapula is displaced forward, and the tumor prominence becomes visible. From the Shoulder and Elbow Clinic, UniversiV Hospital of Aarhus, and the Centres for Bone and Soft Tissue Tumors, University Hospital of Aarhus and State Universily Hospital of Copenhagen. Reprint requests: Tom Nielsen, MD, Shoulder and Elbow Clinic, University Hospital of Aarhus, Randersvej 1, 8200 Aarhus N, Denmark. Copyright @ 1996 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/96/$5.00 + 0 3211169101
Thus the lesion interferes with the scapular-thoracic function and may cause shoulder pain and a snapping scapula. In rare cases it may also cause a slight reduction in shoulder motion. 14 Because the operative findings of the subscapular elastofibroma are similar to those of a sarcoma, it is particularly important to know the benign nature of this lesion to avoid performing unnecessary radical and mutilating excisions. We report six cases of subscapular dastofibroma, focusing on the symptoms and signs especially related to thoracoscapular function. METHODS Six cases of subscapular elastofibroma were diagnosed and treated from 1980 to 1993 at the State University Hospital in Copenhagen and the University Hospital in Aarhus, Denmark. These two centers serve a population of approximately 5 million people. The patients' charts were reviewed for medical history and relevant operative course, and the patients were sent a questionnaire for follow-up. Histologic sections of each case were reviewed to verify the diagnosis. RESULTS The clinical histories and follow-up data are summarized in Table I. Age at the time of diagnosis ranged from 45 to 71 years (average 60 years). Four patients were men, and two were women. 209
210
J. Shoulder Elbow Surg. May/June 1996
Nielsen el al.
Figure 1 Magnetic resonance image of scapular region of patient 1. Encapsulated soft-tissue tumor is seen elevating right scapula (arrows). None of the patients had any history of heavy work, but one (case 3) had worked as a telephonist for 25 years with repetitive movement of the arm in elevated positions. Only one case (2) had a history of trauma, which was a dislocation of the same shoulder 4 years before any tumor symptoms appeared. The tumor mass was the only symptom in two cases. Three cases had posterior shoulder pain during shoulder motion. One of these also had pain at rest, and another had a snapping scapula caused by rubbing of the inferior angle of the scapula on the tumor. Five of the six cases had preoperative physical examination; in all of these the tumor was slightly mobile over the thoracic wall, and superficially the range of scapular motion was normal. Magnetic resonance imaging (MRI) was performed before operation in two cases, and computed tomography was performed in another three. MRI findings indicated a rather well-defined and moderately inhomogenous lesion without any surrounding soft-tissue edema. The tumors were located between the chest wall and the seratus anterior muscle (Figure 1). On Tl-weighted images the lesions had approximately the same signal intensity as skeletal muscle with interspersed linear and curvilinear areas of high-signal intensity. At surgery in all cases but one, the elastofibromas were adherent to the intercostal ligaments and periosteum of the ribs and superficially were closely related to the serratus anterior. In one case a large bursa was found between the serratus
Figure 2 Grossappearance of tumor. Severalcystsare
seen.
muscle and the tumor. The resected specimens consisted of a fibro-fatty mass containing one or more cysts (Figure 2). The size of the specimens varied from 45 cm 3 to 1232 cm 3. Microscopic examination revealed slightly hypocellular fibrous tissue containing variable numbers of wavy fibers. The cells had the appearance of fibroblasts with uniform, ovoid to spindle-shaped nuclei (Figure 3). Mitosis was only rarely seen. Elastic tissue showed variable numbers of irregular and fragmented elastic fibers within the hypocellular fibrous tissue matrix (Figure 4). After incisional biopsy was performed, all patients underwent local excision of the pseudotumor. The tumor was removed by sharp dissection from its attachment to the periosteum of the ribs and intercostal fascia. Because of the nonencapsulated structure, the excisions were intralesional in two cases and marginal in the remaining four. All patients with symptomatic elastofibromas
J. Shoulder Elbow Surg. Volume 5, Number 3
Nielsen et al.
211
Figure 3 Elastofibromashowing slightly hypocellular fibrous tissue containing irregular thick fibers. (Hematoxylin-eosinstain; original magnification x250.)
had complete relief of their pain within a few months after surgery. At follow-up 1 to 8 years after surgery no recurrence has been observed, and all patients with previous symptoms still have complete relief of pain and no restrictions in their range of movement.
DISCUSSION Elastofibromas are rare, with only 350 cases reported in the literature. A total of 170 of these are from one study reporting a special genetic disposition at the Okinawa Island in Japan, ~9 and the remaining information consists of reports of a few cases, 2-5' 8, 9, 14N6, 2 0 with a maximum of 13 cases in two articles, t~ 12 From the Columbian Presbyterian center seven cases of elastofibroma were diagnosed over a lO-year period. ~7 The pseudotumor is nearly always subscapular in location, and very few cases of the tumor in other locations have been reported, including the infraolecranon region, the greater trochanter region, the deltoid muscle, over the ischial tuberosity, the foot, intraspinal, the hand, the orbital area, and the greater omentum.* Histologically elastofibroma is classified as a benign tumorlike lesion of fibrous tissue, and in surgical staging according to Enneking the tumor is benign, stage 1 (latent), or 2 (active). The cause of the pseudotumor is controversial. *References 1, 6, 7, 10, 13, 18, 19, 21.
Figure 4 Elastofibromashowing globules of elastin in
linear arrangement. (Frhof's elastin stain; original magnification x200.)
212
J. ShoulderElbow Surg. May/June 1996
Nielsen et al.
Table I Summary of cases of subscapular dastofibroma Delay from first symptoms to diagnosis
Signs
24 mo
Visible tumor when the arm is elevated
2 mo
Visible tumor when the arm is elevated
Moderate shoulder pain during activity
12 mo
50/M
(Accidentally found during thoracotomy)
None
Visible tumor when the arm is elevated; snapping scapula None
5
45/M
Tumor mass
6 mo
Visible tumor when the arm is elevated
6
68/F
Moderate shoulder pain and tumor mass
4 yr
Visible tumor when the arm is elevated
Case no.
Age (yr)/sex
1
61/M
Tumor mass
2
71/M
Marked subscapular pain
3
62/F
4
Symptoms
M, Male; F, female; MRI, magnetic resonance imaging; CT, computed tomography.
Originally it was thought to be caused by hypertrophy of elastic fibers followed by degeneration and fragmentation. 12' 19 Further understanding of normal elastogenesis has now lead to the opinion that subscapular elastofibroma is a reactive hyperplasia resulting from mechanical friction of the scapula on the chest wall. 12' 15, 18 However, only one study 19 has documented any correlation between heayy work and tumor incidence. All patients are middle-aged or elderly, suggesting a possible degenerative genesis. No clear preference for either sex is evident. One study found a high incidence within the same family line, suggesting genetic disposition, and in fact subscapuFar dastofibroma is bilateral in approximately 10% of the cases, 2' 5. 9, 12, ~6, 19 also suggesting a constitutional influence. An autopsy study showed that 24% of women and 11% of men older than 55 years of age had clinical changes consistent with subscapular elastofibroma. Of these, 46% were bilateral, supporting the theory of constitutional influence, is Because of the history of our patients and the cases described in the literature, we believe that subscapular elastofibroma is a reaction of the fibrous tissue to mechanical stress and friction. The preference for the subscapular area could be explained by the great range of movement in the thoracoscapular articulation and consequently large biomechanical forces acting on the fibrous tissue in this area. The symptoms are not very prominent; often the only symptom is an asymptomatic tumor mass related to the inferior part of the scapula. Sometimes
the only symptom is pain in the posterior part of the shoulder and the scapula, and this pain most often increases with shoulder use. In one of our cases the tumor caused a painful snapping of the scapula. In a few cases the patients may report some stiffness of the shoulder region because of the reduced thoracoscapular motion, but this stiffness is a problem only in overhead work. 1r 19 The signal characteristics on MRI are typical with fibrous tissue and interspersed fatty areas. This factor combined with the location in the scapular area and the benign clinical course makes a one-stage biopsy and surgical procedure preferable in most cases. However, in one of our cases MRI raised suspicion of a malignant fibromatosis, and therefore a twostage procedure was performed. For surgery a posterior approach with release of a portion of the rhomboid muscle from the distal part of scapula gives excellent access to the tumor, especially when the arm is elevated. The tumor mass has ill-defined margins, and an intralesional excision is usually required. The biomechanical aspects of subscapular elastofibroma are interesting. On the thoracic side the tumor is firmly adherent to the intercostal fascia and to the costal periosteum. On the scapular side it seems closely related to the distal part of the serratus anterior muscle and also to the subscapular fascia. On this basis we would expect a rather restricted thoracoscapular motion, but in most instances, including the six cases from our own series,11, 14 the patients had no stiffness, and they had a rather normal range of thoracoscapular motion. If the tumor represents a direct connection
J. Shoulder Elbow Surg. Volume 5, Number 3
Nielsen et al.
Tumor
MRI/CT
Subscapular location
MRI
Distal third of scapula involving chest wall and serratus anterior Distal half of scapula involving chest wall and adherent to serratus anterior Distal third of scapula involving chest wall as well as serratus anterior Distal third of scapula adherent to the chest wall and serratus anterior Distal half of scapula adherent to the chest wall and serratus anterior Distal third of scapula adherent to the chest wall and serratus anterior
MRI CT
CT CT
size (cm)
Treatment
Follow-up (yr)
Intralesional excision
3
14xllx8
Marginal excision
2
10x8x2.5
Marginal excision
1
5x3x2.5
Marginal excision
5
9x7x5
Intralesional excision
4
8x8x4
Marginal excision
8
8x8x4
from the serratus anterior muscle to the chest wall, then the mobility of the scapula would depend only on the biomechanical properties of the tumor. The thickness of the tumor in our series varied from 3 to 7 cm, and of course the elasticity of the rubbery tissue could not allow the normal 6 cm sliding motion of the inferior angle of the scapula to reach a supero-lateral position as it does during normal maximal elevation. The explanation of this phenomenon is that the elastofibroma often develops very slowly over a long period of time, and the highly differentiated tissue seems to adapt to the demands of the thoracoscapular motion. In most cases a loose connective tissue space is found immediately superficial to the tumor, allowing a sliding motion of the scapula, and some cases have a well-defined subscapular bursa. This finding explains why the pseudotumor at physical examination will be only slightly mobile on the thoracic wall, whereas the scapula slides freely over the tumor surface during elevation of the arm. REFERENCES 1. Austin P,Jakobiec FA, Iwarnoto T, Hornblass A. Elastofibroma oculi. Arch Ophthalmd 1983;8:800-2. 2. Benisch B, Peison B, Marquet E, Sobel HJ. Pre-elastofibroma and elastofibroma (the continuum of elastic-producing fibrous turnoursj. A light and dtras~ructurd study. Arn j Ch~ Pathd 1983;80:88-92. 3. Bennett KG, Organ CH, Cook S, Potha J. Bilateral elastofibrima dorsi. Surgery 1988;103:605-7. 4. Bertholy DP, Shulman HS, Miller HA. Elastofibroma chest wall pseudotumor. Radiology 1986;160:341-2. 5. Brown GW. Elastofibroma dorsi: report of ~ o cases and literature review. Wisc Med j 1991;90:2814.
213
6. Cross DL, Mills SE, Kulund DN. Elastofibroma arising in the foot. South Med J 1984;77:1194-6. 7. Enjoji M, Suumiyoshi K, Suwyioshi K. Elastofibromatous lesions of the stomach in a patient with elastofibroma dorsi. AmJ Surg Pathol 1985;9:233-7. 8. Fukuda Y, Miayke H, Masuda Y, Masugi Y. Histogenesis of unique elastinophilic fibers of elastofibroma. Uhrastructural and imrnunohistochemical studies~ Hum Pathol 1987;18: 424-9. 9. Ghiatas AA, Armstrong S, Tio FO. Case report 583. Skeretal Radiol 1989;18:6 ] 9-22. 10. Govoni E, Severi B, Laschi R, Lorenzini P, Baccararini M. Elastofibroma: an in vivo model of abnormal neoelstogenesis. Ultrastruct Pathol 1988;12:327-39. 11. Jarvi OH, Oansimies PH. Subclinical elastofibrorna in the subscapular region in an autopsy series. Acta Pathol Microbiol Scand 1975;83:87-108. 12. Jarvi OH, Saxen E, Hopsu-Havu VK. Elastofibroma: a degeneralive pseudoturnor. Cancer 1969;23:42-63. 13. Kapf PH, Hocken DB, Simpson RHK Elastofibroma of the hand. J Bone Joint Surg Br t987;69B:648-9. 14. Lagae P, Arth A, Dierick E, Achten E, van de Velde E. Elastofibroma dorsi: CT, MR and pathologic study in a new case. J Br Radiol 1992;75:197-201. 15. Lee E, Dlever R, Blanche C. Elastofibroma dorsi. Mt Sinai J Med 51 : 138~40. 16. Machens HG, Mechtersheimer R, Schlag PH. Bilateral elastofibroma dorsi. Ann Thorac Surg 1992;54:774-6. 17. Marin M, Perzin K, Markowitx AM. Elastofibroma dorsi: benign chest wall tumor. J Thorac Cardiovasc Surg 1989; 98:234-8. 18. Mirra JM, Straub LR, Jarvi OH. Elastofibroma of the deltoid. Cancer 1974;33:234-7, 19. Nagamine N, Nogara Y, Ito E. Elastofibroma in Okinawa. A clinicopathologic study of 170 cases. Cancer 1982;50: 1794-805. 20. Nakamura Y, Ohta Y, Itoh S, et ak Elastofibroma dorsi: cytologic, histologic, immunohistochernical and ultrastructural study. Acta Cytol 1992;36:559-62. 21. Prete P, Henbest M, Michalski JP, Porter RW. Intraspinal elastofibroma. A case report. Spine 1983;8:800-2.