Downloaded from www.ajronline.org by 221.233.124.37 on 10/27/15 from IP address 221.233.124.37. Copyright ARRS. For personal use only; all rights reserved
575
Elastofibroma:
MR and CT Appearance with Radiologic-Pathologic Correlation
Mark
J. Kransdorf1’2
Jeanne M. Meis3 Elizabeth Montgomery3
OBJECTIVE. of elastofibroma findings. MATERIALS
The purpose of our study was to determine the MR and CT appearances and correlate the imaging features with the underlying pathologic
five
elastofibroma.
cases
of
AND METHODS.
We reviewed All
patients
retrospectively had
a
the MR and CT findings
soft-tissue
mass;
one
patient
in also
complained of pain. The mean age of the patients was 71 years (range, 63-79 years). Four lesions occurred in the subscapular region, and one occurred in the thigh. In addition, we reviewed and compared the demographic data of 72 histologically proved cases for which we had archival data. RESULTS. Three of four lesions evaluated with spin-echo MR imaging were approximately isointense with skeletal muscle and contained areas with a signal intensity similar to that of fat; these corresponded to areas of dense collagen and interspersed fat, respectively. In the fourth case, the MR appearance was nonspecific. In one case, MR imaging with gadopentetate dimeglumine showed areas with and without enhancement. Three of four lesions evaluated with CT had variable margins, with tissue attenuation similar to that of the adjacent soft tissue as well as scattered areas of decreased
attenuation,
suggesting
fat within the lesion. In one case, the lesion was well defined
and relatively homogeneous with an attenuation less than that of skeletal muscle. CONCLUSION. The MR and CT features of elastofibroma are different from those of most other soft-tissue tumors, reflecting entrapped fat within a predominantly fibrous mass. Although these features are not pathognomonic, their presence in a subscapular lesion in an older patient suggests a presumptive diagnosis of elastofibroma.
AJR
159:575-579,
Elastofibroma Received February vision April 1, 1992.
24, 1992;
accepted
after
re-
The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of
the Department of the Army, the Department Defense, or the Uniformed Services University the Health Sciences. 1
Department
of Radiologic
Forces Institute of Pathology, 20306-6000. Address reprint
Pathology,
of of
Armed
Washington, requests to
M.
DC J.
and
Medi-
Kransdorf. 2
Department
cine,
Uniformed
Sciences,
University
Nuclear
of the Health
Bethesda, MD 20814.
a Department
Forces
of Radiology Services
Institute
of Soft
Tissue
of Pathology,
20306-6000.
036i-803X/92/i
593-0575
Pathology,
Washington,
Armed
DC
from
mechanical
September
is a slowly friction
1992
growing,
between
fibroelastic
the scapula
and
pseudotumor, chest
wall;
thought hence,
to result
it is considered
reactive rather than neoplastic [i , 2]. Originally described at the i2th Congress of Scandinavian Pathologists by J#{228}rvi and Sax#{233}n in i 959, and subsequently reported in i96i [i , 2], elastofibroma has received little attention in the radiologic literature and is considered a rare lesion. However, it is not uncommon and was found in 24% of women and i i % of men in one autopsy series of patients who were more than 55 years old [3]. In this autopsy study, lesions were 3 cm or less in size, suggesting that most elastofibromas are clinically occult, accounting for the perception that they at e rare. As the indications for computerized imaging expand, elastofibroma will probably be seen more frequently. Consequently, radiologists should be familiar with the imaging and clinical characteristics of this entity. This knowledge may make a correct presumptive diagnosis possible and prevent unnecessary radical surgery. We describe the CT and MR appearances of five elastofibromas and correlate the imaging features with the histologic findings. In addition, we review the demographic data of another 72 patients.
KRANSDORF
576
Materials
and Methods
We reviewed patients ation
retrospectively
of a soft-tissue
Downloaded from www.ajronline.org by 221.233.124.37 on 10/27/15 from IP address 221.233.124.37. Copyright ARRS. For personal use only; all rights reserved
graphic
data
mass
from
the MR images and CT scans of five all of whom
(one
consisted
old (mean, 7i years).
patient
were also
imaged
for the evalu-
complained
another
we reviewed
72 cases
years
the archival
demo-
The
entire
in one case. Seventy-three lesions occurred between scapula and the chest wall, two occurred in the thigh, region
of the
hip
attached
to the
fascia
lata
the tip of the one occurred
femoris,
and
one
foot. The size of the lesion was known in 63 cases and ranged from i .5 to 20.0 cm in greatest dimension (mean, 8 cm). The size was unkown in 14 cases. Thirtyfive cases involved the right side, and 25 involved the left; the side occurred
in the
second
web
space
involved was unknown in 17. In four patients, MR images variety
unknown
of
systems.
Field
in one. Images
strength
included
September
1992
dimeglumine-enhanced MR images were obtained in Ti - and T2-weighted images. All lesions were
standard
in at least
two
orthogonal
planes.
two with and two without
In all cases,
63-79
of elastofibroma.
to
imaged
of increasing
of four men and one woman
In addition,
addition
scans,
group of 77 lesions occurred in 75 patients 36-8i years old (mean, 69 years); two patients had bilateral subscapular masses. The combined groups included 42 men and 32 women; the sex was unknown
in the
AJR:i59,
gadopentetate
with elastofibroma,
pain). This group
ET AL.
cally
according
with
hematoxylin
the
diagnosis
to criteria and
patients was
described
were
had
axial
CT
material.
of elastofibroma
previously eosin
Four
contrast
reviewed
[1
without
edge of each lesions’s radiologic appearance; lated with each patient’s MR and CT findings.
verified
histologi-
-3]. Sections
stained
previous
they were
knowl-
then corre-
Results MR Findings
of the
of the lesions was
spin-echo
i .5
were T in
obtained three
Ti -weighted
with
cases
a
and
(300-767/
20-30) and T2-weighted (2000-2090/90) pulse sequences. tient’s lesion was evaluated by using short TI inversion (STIR) (200/45/i 65) and gradient-refocused echo (GRE) 20#{176}) MR images rather than T2-weighted images. In one
One parecovery (3i 7/i 5/ patient,
In three
of four
cases,
all tumors
in the subscapular
region,
spin-echo MR images showed relatively well defined, moderately inhomogeneous lesions, with no surrounding soft-tissue edema. On Ti-weighted images, the lesions had approximately the same signal intensity as skeletal muscle, with interspersed linear and curvilinear areas of high signal intensity. On corresponding T2-weighted images, the lesions also had a signal intensity approximately the same as that of skeletal
peared
muscle,
similar
with
linear
and
to fat in a distribution
Fig.
curvilinear
areas
i.-Subscapular
elastofibroma
year-old woman. A and B, Corresponding (550/22)
that
ap-
like that seen on the Ti
axial
(A) and T2-weighted
in
-
64-
Ti-weighted
(2000/90)
(B) SE
MR images show a relatively well defined, inhomogeneous mass (arrows) between chest wall and scapular tip. Most of mass has a signal intensity rounding
approximately equal to that skeletal muscle. Interspersed
of surwithin
mass are linear and curvilinear areas with increased signal intensity approximately the same as that of subcutaneous fat.
Fig. 2.-Elastofibroma
in anterior
thigh of 73-
year-old man. A, Axial TI-weighted (300/20) SE MR image shows a mass (arrowhead) with relatively homogeneous region centrally, with only a few small globular areas of increased signal intensity, surrounded by a region that has several interspersed areas with signal intensity similar to that of fat. Lesion is poorly delineated from adjacent tissue. B, Sagittal GRE MR image (317/15/20#{176})
shows a relatively inhomogeneous nonspecific mass (arrows) with a signal intensity greater than that of fat
AJR:i59,
September
weighted
MR
1992
images
(Fig.
i).
Gadopentetate
AND
CT
OF
Histologic
dimeglumine-en-
Downloaded from www.ajronline.org by 221.233.124.37 on 10/27/15 from IP address 221.233.124.37. Copyright ARRS. For personal use only; all rights reserved
hanced MR images in one case showed areas with and without enhancement. A single lesion in the thigh was poorly defined on Ti -weighted images. It had a relatively homogeneous region centrally and a few small globular areas of increased signal intensity surrounded by a region with several interspersed areas of high signal intensity. GRE images in this case showed the lesion was a relatively well defined inhomogeneous nonspecific mass with a signal intensity
greater than that of fat (Fig. 2). STIR images showed defined inhomogeneous mass.
a poorly
Axial CT scans offour variable
lesions, all in the subscapular
margins.
In three
of four
cases,
adjacent
soft
tissue,
with
some
scattered
areas
of
decreased attenuation (Fig. 3). In one case, the lesion was relatively homogeneous, with an attenuation less than that of skeletal muscle (Fig. 4). In no case was an underlying osseous abnormality detected.
Fig.
3.-Subscapular
elastofibroma
in
68-
year-old man. Axial noncontrast
CT scan shows Note subtle of decreased attenuation within mass. Although well outiined by fat laterally, lesion canlarge areas
subscapular
not be separated
mass
(arrows).
from Intercostal
muscles.
Fig. 4.-Subscapular elastofibroma in 79year-old man. Axial noncontrast CT scan shows large homogeneous subscapular mass (arrows) with tissue
attenuation
less than that of skeletal
muscle and greater than that of subcutaneous fat.
Fig. 5.-Histologic
features
A, Low-power photomicrograph composed primarily of hyalinized
scattered
Findings
Microscopically, all lesions were composed primarily of hyalinized collagen with scattered fibroblasts and entrapped islands of mature adipose tissue. In all cases, variable numbers of characteristically enlarged, hypereosinophilic, refractile elastic fibrils were present. They resembled a pipe cleaner in longitudinal
sections, hoeff-van
region, the mass
was well outlined laterally by fat, but was not separable from the muscles of the chest wall anteromedially. The tissue attenuation of the lesion was approximately the same as that of the
577
sections
and
an asterisk
or a flower
in
particularly with the stain for elastic tissue Gieson stain for elastic fibrils) (Fig. 5).
cross (Ver-
Discussion
CT Findings showed
ELASTOFIBROMA
fibroblasts
of elastofibroma. shows lesion, collagen with
and entrapped
islands
of
mature adipose tissue, Infiltrating adjacent adipose tissue. (H and E, original magnification x75) B, High-power photomicrograph shows characteristic serrated fibrils, which resemble a pipe cleaner in longitudinal sections and an asterisk or a flower in cross sections. (Verhoeff-van Gieson elastic stain, original magnification x300)
Elastofibroma
is
not
a true
neoplasm
considered to be a fibroblastic arises from periosteal fibroblasts logenesis [4]. Lesions typically
and
is generally
pseudotumor; it probably with deranged elastic fibriloccur on the back and are
thought to be related to repeated mechanical friction between the chest wall and the tip of the scapula. Patients often have an
occupational
however, number occult
history
of
manual
this may be a coincidence of elastofibromas clinical
nature
found of this
entity
labor
such
as
farming;
[i , 2, 5, 6] in view of the
at autopsy
and the presumed
[3]. Other types of trauma,
KRANSDORF
578
mechanical
stress,
chronic
irritation,
and nutritional
derange-
Downloaded from www.ajronline.org by 221.233.124.37 on 10/27/15 from IP address 221.233.124.37. Copyright ARRS. For personal use only; all rights reserved
ment have also been suggested as etiologic factors [3, 7], but these factors alone may not explain the development of
ET
AL.
AJR:159,
in size. Cystic change within the lesion has been reported [2, 5], as have bursalike areas [3, 9]. Lesions may be stable or may grow slowly over many years [5, 6]. Surgery is considered
i70 cases of the lesion in Okinawa in which one third of the patients had a family history of elastofibroma. Barr [8] postulated that “the lesion results from elastic degeneration of collagen following trauma and friction in individuals who possibly have some inherited enzymatic defect related to connective tissue metabolism.” However, recent in situ hybridization
had
consists of (i) fibroblasts scattered among closely packed bundles of normally formed collagen fibrils and (2) aggregates of abnormally formed elastic fibrils of various diameters and
shapes [i}. The location tip is most
between
the chest wall and inferior
characteristic
of elastofibroma;
it was
scapular the site of
Na-
gamine et al. [5] found that this area was involved
in approx-
imately
synchron-
1 6% of patients.
ous lesions
They
in the thoracic
tuberosity. One patient locations. Elastofibromas [9], foot [1 0], regions
also noted
isolated
wall and in the area of the ischial
had lesions in seven different anatomic in other locations such as the hand overlying the greater trochanter and
ischial tuberosity [8, i 1], deltoid region [7], temporal bulbar conjunctiva [i 2], and cervical epidural space [i3] have also been reported. Most patients are older adults. The mean age of patients is approximately 70 years [5], although elastofibroma has been reported in children as young as 6 years [6]. More than half the patients are asymptomatic [5, 6]. The most common symptom is stiffness, which is seen in approximately one fourth of patients [5]. Pain is relatively uncommon and is the presenting symptom in another i 0% [5]. Large lesions may
ulcerate
[14]. The disorder
ally estimated
i3:i
to be 2:i
has a female predominance,
[3, 7]; however,
usu-
it may be as high as
[5].
Our series had an unusually high percentage of men, which is partially explained by a biased referral pattern. Fourteen patients in our series were referred from federal (military or veterans administration) hospitals; i 1 of these were men, two were women, and for one the sex was unknown. If only cases
referred from civilian sources are considered, the group included 30 men and 3i women, which is still a higher percentage of men than reported in the literature. Lesions may be as large as 20 cm and may be manifested as a soft-tissue mass; however, elastofibroma may also produce a thickened and indurated area of the thoracic fascia or a “streak in the fascia” detected on histologic examination [3, i 5]. The great discrepancy between the prevalence of elastofibroma in autopsy series vs the prevalence of clinically apparent mass lesions is likely related to the lesion’s great
recurrences
are
probably
of the patients
due
to
in our study
density
is a poorly
with
defined
attenuation
inhomogeneous
approximately
the
same
as that
of skeletal muscle and containing linear low-density streaks [6, i 5, i 6]. Three of our four cases had this appearance. In the fourth case, the lesion was relatively homogeneous, with an attenuation less than that of muscle; this was somewhat similar to the findings reported by Mann et al. [6]. Gould et al. [i7] described the MR findings in a patient with bilateral
elastofibromas
weighted
images,
the
an
intermediate
mass
with
equal to that of skeletal intensity similar to that the appearance
of the
scapula.
lesion
was
a lenticular
signal
intensity
muscle; of fat.
of the three
decreased
signal
connective
This
chest
intensity
tissue,
On both
interlaced
areas of increased signal intensity adipose tissue within the lesion, fibrous
common.
rare
Five (7%)
2-i 7 years after surgery.
recurrences
soft-tissue
tively
are also
excision.
On CT, elastofibroma
Synchronous
lesions
curative;
incomplete
the lesion in 99% of reported cases [5]. Bilateral lesions are common and are seen in i 0-66% of patients [2, 3, 5, 6, 8]. infraolecranon
1992
variability
elastofibroma. Some patients may also have a genetic predisposition, as suggested by a study by Nagamine et al. [5] of
and immunoelectron microscopic studies indicate that active synthesis of elastic fibrils is occurring within elastofibromas and that elastic fibrillogenesis is abnormal rather than a degenerative phenomenon [4]. Ultrastructurally, elastofibroma
September
lesions
T2-
approximately had
appearance
wall
and
well-defined
areas
a signal
is similar we report.
to The
presumably correspond to whereas the areas of relacorrespond
which
Ti-
to areas
predominate.
The
of dense origin
of
the fat within the lesion could not be determined; however, we speculate that it is entrapped mature adipose tissue. Although factors governing enhancement on MR images obtamed with gadopentetate dimeglumine are not completely
understood, in other The
we note that similar enhancement
densely
fibrous
differential
lesions
diagnosis
has been seen
[i 8]. of
lesions
that
have
increased
signal intensity on Ti -weighted MR images is limited. All of these contain either fat or blood and in addition to elastofibroma include lipoma, liposarcoma, hemangioma, hematoma, and intralesional hemorrhage [i 9]. Similarly, the differential diagnosis of lesions with decreased or relatively decreased signal intensity on both Ti - and T2-weighted MR images limited. This includes densely those that are hemosiderin-laden, nodular large
synovitis, amounts
neurotic intensity
or those of collagen,
fibromatosis or on all spin-echo
mineralized such that
are
as in some
is
masses as well as as pigmented villo-
relatively cases
acellular
with
of musculoapo-
desmoid [i 9]. Decreased signal MR pulse sequences has been
reported in malignant fibrous histiocytoma and in other malignant tumors and is not specific for any diagnosis; it simply reflects the morphologic features of a lesion [19, 20]. The imaging features of elastofibroma are different from those of most other soft-tissue tumors, reflecting entrapped fat within a predominantly fibrous mass. Although these features are not pathognomonic, their presence in a subscapular lesion in an older patient suggests a presumptive diagnosis of elastofibroma.
ACKNOWLEDGMENT We thank
preparation
Sheela
of
this
Rao for her untiring manuscript.
research
assistance
in the
AJR:159,
September
MR
1992
AND
CT
OF
REFERENCES
10.
Cross
DL, Mills
MOdJ 1 1 . Waisman 1 . J#{228}rvi OH,
Sax#{233}nAE. Elastofibroma
1961;144[suppl
dorsi.
Acta
Pathol
Microbiol
Downloaded from www.ajronline.org by 221.233.124.37 on 10/27/15 from IP address 221.233.124.37. Copyright ARRS. For personal use only; all rights reserved
J#{228}rvi OH, Sax#{233}nAE, Hopsu-Havu vK, Wartiovaara JJ, vaissalo vT. Elastofibroma: a degenerative pseudotumor. Cancer 1969;23:42-63 3. Jrvi OH, L#{228}nsimies PH. Subclinical elastofibromas in the scapular region in an autopsy series: additional notes on the aetiology and pathogenesis of elastofibroma pseudoneoplasm. Acta Pathol Microbiol Scand [A] 1975;83:87-108 4. Kumaratilake JS, Krishnan R, Lomax-Smith J, Cleary EG. Elastofibroma: disturbed elastic fibrillogenesis by periosteal-derived cells? An immunoelectron microscopic and in situ hybridization study. Hum Patho! 1991;22: 101 7-1 029 5. Nagamine N, Nohara Y, Ito E. Elastofibroma in Okinawa: a clinicopathologic study of 170 cases. Cancer 1982;50: 1794-i 805
AM. Elastofibroma
dorsi: benign chest
wall tumor. J Thorac Cardiovasc Surg 1989;98:234-238 JM, Straub LR, J#{228}rvi OH. Elastofibroma of the deltoid.
7. Mirra
DN. Elastofibroma
arising
in the foot.
South
J,
Smith
DW.
Fine
structure
of
an
elastofibroma.
Cancer
12.
2.
6. Marin ML, Perzin KH, Markowitz
SE, Kulund
i984;77:i194-i196
1968;22:671-677
Scand
51]:83-84
579
ELASTOFIBROMA
Austin P, Jakobiec FA, Iwamoto T, Homblass A. Elastofibroma oculi. Arch Ophthalmol 1983;101 : 1575-1 579 13. Prete PE, Henbest M, Michalski JP, Porter RW. Intraspinal elastofibroma: a case report. Spine 1983;8:800-802 14. Schwarz T, Opplzer G, Duschet P, BrUckler B, Gschnait F. ticerating elastofibroma dorsi. J Am Acad Dermato! 1989:21:1142-1144 1 5. Ghiatas AA, Armstrong 5, Fermin OT. Case report 583 (Elastofibroma dorsi). Skeletal Radiol 1989;18:619-622 1 6. Berthoty DP, Shulman HS, Miller HAB. Elastofibroma: chest wall pseudotumor. Radiology 1986;160:341-342 17. Gould ES, Javors BR, Morrison J, Potter H. Case report. MR appearance of bilateral periscapular elastofibromas. J Comput Assist Tomogr
1989;13:70i -703 18.
Cancer
19.
8. Barr JR. Elastofibroma. Am J Clin Pathol 1966;45:679-683 9. Kapif PD, Hocken DB, Simpson RHW. Elastofibroma of the hand. J Bone Joint Surg [Br] 1987;69-B:468-469
20.
1974;33:234-238
Hawnaur JM, Jenkins JPR, Isherwood I. Magnetic resonance imaging of musculoaponeurotic fibromatosis. Skeletal Radiol 1990;i9:509-514 Sundaram M, McLeod RA. MR imaging of tumor and tumorlike lesions of bone and soft tissue. AJR 1990;155:817-824 Sundaram M, McGuire MH, Schajowicz F. Soft-tissue masses: histologic basis for decreased signal (short T2) on T2-weighted MR images. AJR
i987;148:1247-1
250
575
Elastofibroma:
MR and CT Appearance with Radiologic-Pathologic Correlation
Mark
J. Kransdorf1’2
Jeanne M. Meis3 Elizabeth Montgomery3
OBJECTIVE. of elastofibroma findings. MATERIALS
The purpose of our study was to determine the MR and CT appearances and correlate the imaging features with the underlying pathologic
five
elastofibroma.
cases
of
AND METHODS.
We reviewed All
patients
retrospectively had
a
the MR and CT findings
soft-tissue
mass;
one
patient
in also
complained of pain. The mean age of the patients was 71 years (range, 63-79 years). Four lesions occurred in the subscapular region, and one occurred in the thigh. In addition, we reviewed and compared the demographic data of 72 histologically proved cases for which we had archival data. RESULTS. Three of four lesions evaluated with spin-echo MR imaging were approximately isointense with skeletal muscle and contained areas with a signal intensity similar to that of fat; these corresponded to areas of dense collagen and interspersed fat, respectively. In the fourth case, the MR appearance was nonspecific. In one case, MR imaging with gadopentetate dimeglumine showed areas with and without enhancement. Three of four lesions evaluated with CT had variable margins, with tissue attenuation similar to that of the adjacent soft tissue as well as scattered areas of decreased
attenuation,
suggesting
fat within the lesion. In one case, the lesion was well defined
and relatively homogeneous with an attenuation less than that of skeletal muscle. CONCLUSION. The MR and CT features of elastofibroma are different from those of most other soft-tissue tumors, reflecting entrapped fat within a predominantly fibrous mass. Although these features are not pathognomonic, their presence in a subscapular lesion in an older patient suggests a presumptive diagnosis of elastofibroma.
AJR
159:575-579,
Elastofibroma Received February vision April 1, 1992.
24, 1992;
accepted
after
re-
The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of
the Department of the Army, the Department Defense, or the Uniformed Services University the Health Sciences. 1
Department
of Radiologic
Forces Institute of Pathology, 20306-6000. Address reprint
Pathology,
of of
Armed
Washington, requests to
M.
DC J.
and
Medi-
Kransdorf. 2
Department
cine,
Uniformed
Sciences,
University
Nuclear
of the Health
Bethesda, MD 20814.
a Department
Forces
of Radiology Services
Institute
of Soft
Tissue
of Pathology,
20306-6000.
036i-803X/92/i
593-0575
Pathology,
Washington,
Armed
DC
from
mechanical
September
is a slowly friction
1992
growing,
between
fibroelastic
the scapula
and
pseudotumor, chest
wall;
thought hence,
to result
it is considered
reactive rather than neoplastic [i , 2]. Originally described at the i2th Congress of Scandinavian Pathologists by J#{228}rvi and Sax#{233}n in i 959, and subsequently reported in i96i [i , 2], elastofibroma has received little attention in the radiologic literature and is considered a rare lesion. However, it is not uncommon and was found in 24% of women and i i % of men in one autopsy series of patients who were more than 55 years old [3]. In this autopsy study, lesions were 3 cm or less in size, suggesting that most elastofibromas are clinically occult, accounting for the perception that they at e rare. As the indications for computerized imaging expand, elastofibroma will probably be seen more frequently. Consequently, radiologists should be familiar with the imaging and clinical characteristics of this entity. This knowledge may make a correct presumptive diagnosis possible and prevent unnecessary radical surgery. We describe the CT and MR appearances of five elastofibromas and correlate the imaging features with the histologic findings. In addition, we review the demographic data of another 72 patients.
KRANSDORF
576
Materials
and Methods
We reviewed patients ation
retrospectively
of a soft-tissue
Downloaded from www.ajronline.org by 221.233.124.37 on 10/27/15 from IP address 221.233.124.37. Copyright ARRS. For personal use only; all rights reserved
graphic
data
mass
from
the MR images and CT scans of five all of whom
(one
consisted
old (mean, 7i years).
patient
were also
imaged
for the evalu-
complained
another
we reviewed
72 cases
years
the archival
demo-
The
entire
in one case. Seventy-three lesions occurred between scapula and the chest wall, two occurred in the thigh, region
of the
hip
attached
to the
fascia
lata
the tip of the one occurred
femoris,
and
one
foot. The size of the lesion was known in 63 cases and ranged from i .5 to 20.0 cm in greatest dimension (mean, 8 cm). The size was unkown in 14 cases. Thirtyfive cases involved the right side, and 25 involved the left; the side occurred
in the
second
web
space
involved was unknown in 17. In four patients, MR images variety
unknown
of
systems.
Field
in one. Images
strength
included
September
1992
dimeglumine-enhanced MR images were obtained in Ti - and T2-weighted images. All lesions were
standard
in at least
two
orthogonal
planes.
two with and two without
In all cases,
63-79
of elastofibroma.
to
imaged
of increasing
of four men and one woman
In addition,
addition
scans,
group of 77 lesions occurred in 75 patients 36-8i years old (mean, 69 years); two patients had bilateral subscapular masses. The combined groups included 42 men and 32 women; the sex was unknown
in the
AJR:i59,
gadopentetate
with elastofibroma,
pain). This group
ET AL.
cally
according
with
hematoxylin
the
diagnosis
to criteria and
patients was
described
were
had
axial
CT
material.
of elastofibroma
previously eosin
Four
contrast
reviewed
[1
without
edge of each lesions’s radiologic appearance; lated with each patient’s MR and CT findings.
verified
histologi-
-3]. Sections
stained
previous
they were
knowl-
then corre-
Results MR Findings
of the
of the lesions was
spin-echo
i .5
were T in
obtained three
Ti -weighted
with
cases
a
and
(300-767/
20-30) and T2-weighted (2000-2090/90) pulse sequences. tient’s lesion was evaluated by using short TI inversion (STIR) (200/45/i 65) and gradient-refocused echo (GRE) 20#{176}) MR images rather than T2-weighted images. In one
One parecovery (3i 7/i 5/ patient,
In three
of four
cases,
all tumors
in the subscapular
region,
spin-echo MR images showed relatively well defined, moderately inhomogeneous lesions, with no surrounding soft-tissue edema. On Ti-weighted images, the lesions had approximately the same signal intensity as skeletal muscle, with interspersed linear and curvilinear areas of high signal intensity. On corresponding T2-weighted images, the lesions also had a signal intensity approximately the same as that of skeletal
peared
muscle,
similar
with
linear
and
to fat in a distribution
Fig.
curvilinear
areas
i.-Subscapular
elastofibroma
year-old woman. A and B, Corresponding (550/22)
that
ap-
like that seen on the Ti
axial
(A) and T2-weighted
in
-
64-
Ti-weighted
(2000/90)
(B) SE
MR images show a relatively well defined, inhomogeneous mass (arrows) between chest wall and scapular tip. Most of mass has a signal intensity rounding
approximately equal to that skeletal muscle. Interspersed
of surwithin
mass are linear and curvilinear areas with increased signal intensity approximately the same as that of subcutaneous fat.
Fig. 2.-Elastofibroma
in anterior
thigh of 73-
year-old man. A, Axial TI-weighted (300/20) SE MR image shows a mass (arrowhead) with relatively homogeneous region centrally, with only a few small globular areas of increased signal intensity, surrounded by a region that has several interspersed areas with signal intensity similar to that of fat. Lesion is poorly delineated from adjacent tissue. B, Sagittal GRE MR image (317/15/20#{176})
shows a relatively inhomogeneous nonspecific mass (arrows) with a signal intensity greater than that of fat
AJR:i59,
September
weighted
MR
1992
images
(Fig.
i).
Gadopentetate
AND
CT
OF
Histologic
dimeglumine-en-
Downloaded from www.ajronline.org by 221.233.124.37 on 10/27/15 from IP address 221.233.124.37. Copyright ARRS. For personal use only; all rights reserved
hanced MR images in one case showed areas with and without enhancement. A single lesion in the thigh was poorly defined on Ti -weighted images. It had a relatively homogeneous region centrally and a few small globular areas of increased signal intensity surrounded by a region with several interspersed areas of high signal intensity. GRE images in this case showed the lesion was a relatively well defined inhomogeneous nonspecific mass with a signal intensity
greater than that of fat (Fig. 2). STIR images showed defined inhomogeneous mass.
a poorly
Axial CT scans offour variable
lesions, all in the subscapular
margins.
In three
of four
cases,
adjacent
soft
tissue,
with
some
scattered
areas
of
decreased attenuation (Fig. 3). In one case, the lesion was relatively homogeneous, with an attenuation less than that of skeletal muscle (Fig. 4). In no case was an underlying osseous abnormality detected.
Fig.
3.-Subscapular
elastofibroma
in
68-
year-old man. Axial noncontrast
CT scan shows Note subtle of decreased attenuation within mass. Although well outiined by fat laterally, lesion canlarge areas
subscapular
not be separated
mass
(arrows).
from Intercostal
muscles.
Fig. 4.-Subscapular elastofibroma in 79year-old man. Axial noncontrast CT scan shows large homogeneous subscapular mass (arrows) with tissue
attenuation
less than that of skeletal
muscle and greater than that of subcutaneous fat.
Fig. 5.-Histologic
features
A, Low-power photomicrograph composed primarily of hyalinized
scattered
Findings
Microscopically, all lesions were composed primarily of hyalinized collagen with scattered fibroblasts and entrapped islands of mature adipose tissue. In all cases, variable numbers of characteristically enlarged, hypereosinophilic, refractile elastic fibrils were present. They resembled a pipe cleaner in longitudinal
sections, hoeff-van
region, the mass
was well outlined laterally by fat, but was not separable from the muscles of the chest wall anteromedially. The tissue attenuation of the lesion was approximately the same as that of the
577
sections
and
an asterisk
or a flower
in
particularly with the stain for elastic tissue Gieson stain for elastic fibrils) (Fig. 5).
cross (Ver-
Discussion
CT Findings showed
ELASTOFIBROMA
fibroblasts
of elastofibroma. shows lesion, collagen with
and entrapped
islands
of
mature adipose tissue, Infiltrating adjacent adipose tissue. (H and E, original magnification x75) B, High-power photomicrograph shows characteristic serrated fibrils, which resemble a pipe cleaner in longitudinal sections and an asterisk or a flower in cross sections. (Verhoeff-van Gieson elastic stain, original magnification x300)
Elastofibroma
is
not
a true
neoplasm
considered to be a fibroblastic arises from periosteal fibroblasts logenesis [4]. Lesions typically
and
is generally
pseudotumor; it probably with deranged elastic fibriloccur on the back and are
thought to be related to repeated mechanical friction between the chest wall and the tip of the scapula. Patients often have an
occupational
however, number occult
history
of
manual
this may be a coincidence of elastofibromas clinical
nature
found of this
entity
labor
such
as
farming;
[i , 2, 5, 6] in view of the
at autopsy
and the presumed
[3]. Other types of trauma,
KRANSDORF
578
mechanical
stress,
chronic
irritation,
and nutritional
derange-
Downloaded from www.ajronline.org by 221.233.124.37 on 10/27/15 from IP address 221.233.124.37. Copyright ARRS. For personal use only; all rights reserved
ment have also been suggested as etiologic factors [3, 7], but these factors alone may not explain the development of
ET
AL.
AJR:159,
in size. Cystic change within the lesion has been reported [2, 5], as have bursalike areas [3, 9]. Lesions may be stable or may grow slowly over many years [5, 6]. Surgery is considered
i70 cases of the lesion in Okinawa in which one third of the patients had a family history of elastofibroma. Barr [8] postulated that “the lesion results from elastic degeneration of collagen following trauma and friction in individuals who possibly have some inherited enzymatic defect related to connective tissue metabolism.” However, recent in situ hybridization
had
consists of (i) fibroblasts scattered among closely packed bundles of normally formed collagen fibrils and (2) aggregates of abnormally formed elastic fibrils of various diameters and
shapes [i}. The location tip is most
between
the chest wall and inferior
characteristic
of elastofibroma;
it was
scapular the site of
Na-
gamine et al. [5] found that this area was involved
in approx-
imately
synchron-
1 6% of patients.
ous lesions
They
in the thoracic
tuberosity. One patient locations. Elastofibromas [9], foot [1 0], regions
also noted
isolated
wall and in the area of the ischial
had lesions in seven different anatomic in other locations such as the hand overlying the greater trochanter and
ischial tuberosity [8, i 1], deltoid region [7], temporal bulbar conjunctiva [i 2], and cervical epidural space [i3] have also been reported. Most patients are older adults. The mean age of patients is approximately 70 years [5], although elastofibroma has been reported in children as young as 6 years [6]. More than half the patients are asymptomatic [5, 6]. The most common symptom is stiffness, which is seen in approximately one fourth of patients [5]. Pain is relatively uncommon and is the presenting symptom in another i 0% [5]. Large lesions may
ulcerate
[14]. The disorder
ally estimated
i3:i
to be 2:i
has a female predominance,
[3, 7]; however,
usu-
it may be as high as
[5].
Our series had an unusually high percentage of men, which is partially explained by a biased referral pattern. Fourteen patients in our series were referred from federal (military or veterans administration) hospitals; i 1 of these were men, two were women, and for one the sex was unknown. If only cases
referred from civilian sources are considered, the group included 30 men and 3i women, which is still a higher percentage of men than reported in the literature. Lesions may be as large as 20 cm and may be manifested as a soft-tissue mass; however, elastofibroma may also produce a thickened and indurated area of the thoracic fascia or a “streak in the fascia” detected on histologic examination [3, i 5]. The great discrepancy between the prevalence of elastofibroma in autopsy series vs the prevalence of clinically apparent mass lesions is likely related to the lesion’s great
recurrences
are
probably
of the patients
due
to
in our study
density
is a poorly
with
defined
attenuation
inhomogeneous
approximately
the
same
as that
of skeletal muscle and containing linear low-density streaks [6, i 5, i 6]. Three of our four cases had this appearance. In the fourth case, the lesion was relatively homogeneous, with an attenuation less than that of muscle; this was somewhat similar to the findings reported by Mann et al. [6]. Gould et al. [i7] described the MR findings in a patient with bilateral
elastofibromas
weighted
images,
the
an
intermediate
mass
with
equal to that of skeletal intensity similar to that the appearance
of the
scapula.
lesion
was
a lenticular
signal
intensity
muscle; of fat.
of the three
decreased
signal
connective
This
chest
intensity
tissue,
On both
interlaced
areas of increased signal intensity adipose tissue within the lesion, fibrous
common.
rare
Five (7%)
2-i 7 years after surgery.
recurrences
soft-tissue
tively
are also
excision.
On CT, elastofibroma
Synchronous
lesions
curative;
incomplete
the lesion in 99% of reported cases [5]. Bilateral lesions are common and are seen in i 0-66% of patients [2, 3, 5, 6, 8]. infraolecranon
1992
variability
elastofibroma. Some patients may also have a genetic predisposition, as suggested by a study by Nagamine et al. [5] of
and immunoelectron microscopic studies indicate that active synthesis of elastic fibrils is occurring within elastofibromas and that elastic fibrillogenesis is abnormal rather than a degenerative phenomenon [4]. Ultrastructurally, elastofibroma
September
lesions
T2-
approximately had
appearance
wall
and
well-defined
areas
a signal
is similar we report.
to The
presumably correspond to whereas the areas of relacorrespond
which
Ti-
to areas
predominate.
The
of dense origin
of
the fat within the lesion could not be determined; however, we speculate that it is entrapped mature adipose tissue. Although factors governing enhancement on MR images obtamed with gadopentetate dimeglumine are not completely
understood, in other The
we note that similar enhancement
densely
fibrous
differential
lesions
diagnosis
has been seen
[i 8]. of
lesions
that
have
increased
signal intensity on Ti -weighted MR images is limited. All of these contain either fat or blood and in addition to elastofibroma include lipoma, liposarcoma, hemangioma, hematoma, and intralesional hemorrhage [i 9]. Similarly, the differential diagnosis of lesions with decreased or relatively decreased signal intensity on both Ti - and T2-weighted MR images limited. This includes densely those that are hemosiderin-laden, nodular large
synovitis, amounts
neurotic intensity
or those of collagen,
fibromatosis or on all spin-echo
mineralized such that
are
as in some
is
masses as well as as pigmented villo-
relatively cases
acellular
with
of musculoapo-
desmoid [i 9]. Decreased signal MR pulse sequences has been
reported in malignant fibrous histiocytoma and in other malignant tumors and is not specific for any diagnosis; it simply reflects the morphologic features of a lesion [19, 20]. The imaging features of elastofibroma are different from those of most other soft-tissue tumors, reflecting entrapped fat within a predominantly fibrous mass. Although these features are not pathognomonic, their presence in a subscapular lesion in an older patient suggests a presumptive diagnosis of elastofibroma.
ACKNOWLEDGMENT We thank
preparation
Sheela
of
this
Rao for her untiring manuscript.
research
assistance
in the
AJR:159,
September
MR
1992
AND
CT
OF
REFERENCES
10.
Cross
DL, Mills
MOdJ 1 1 . Waisman 1 . J#{228}rvi OH,
Sax#{233}nAE. Elastofibroma
1961;144[suppl
dorsi.
Acta
Pathol
Microbiol
Downloaded from www.ajronline.org by 221.233.124.37 on 10/27/15 from IP address 221.233.124.37. Copyright ARRS. For personal use only; all rights reserved
J#{228}rvi OH, Sax#{233}nAE, Hopsu-Havu vK, Wartiovaara JJ, vaissalo vT. Elastofibroma: a degenerative pseudotumor. Cancer 1969;23:42-63 3. Jrvi OH, L#{228}nsimies PH. Subclinical elastofibromas in the scapular region in an autopsy series: additional notes on the aetiology and pathogenesis of elastofibroma pseudoneoplasm. Acta Pathol Microbiol Scand [A] 1975;83:87-108 4. Kumaratilake JS, Krishnan R, Lomax-Smith J, Cleary EG. Elastofibroma: disturbed elastic fibrillogenesis by periosteal-derived cells? An immunoelectron microscopic and in situ hybridization study. Hum Patho! 1991;22: 101 7-1 029 5. Nagamine N, Nohara Y, Ito E. Elastofibroma in Okinawa: a clinicopathologic study of 170 cases. Cancer 1982;50: 1794-i 805
AM. Elastofibroma
dorsi: benign chest
wall tumor. J Thorac Cardiovasc Surg 1989;98:234-238 JM, Straub LR, J#{228}rvi OH. Elastofibroma of the deltoid.
7. Mirra
DN. Elastofibroma
arising
in the foot.
South
J,
Smith
DW.
Fine
structure
of
an
elastofibroma.
Cancer
12.
2.
6. Marin ML, Perzin KH, Markowitz
SE, Kulund
i984;77:i194-i196
1968;22:671-677
Scand
51]:83-84
579
ELASTOFIBROMA
Austin P, Jakobiec FA, Iwamoto T, Homblass A. Elastofibroma oculi. Arch Ophthalmol 1983;101 : 1575-1 579 13. Prete PE, Henbest M, Michalski JP, Porter RW. Intraspinal elastofibroma: a case report. Spine 1983;8:800-802 14. Schwarz T, Opplzer G, Duschet P, BrUckler B, Gschnait F. ticerating elastofibroma dorsi. J Am Acad Dermato! 1989:21:1142-1144 1 5. Ghiatas AA, Armstrong 5, Fermin OT. Case report 583 (Elastofibroma dorsi). Skeletal Radiol 1989;18:619-622 1 6. Berthoty DP, Shulman HS, Miller HAB. Elastofibroma: chest wall pseudotumor. Radiology 1986;160:341-342 17. Gould ES, Javors BR, Morrison J, Potter H. Case report. MR appearance of bilateral periscapular elastofibromas. J Comput Assist Tomogr
1989;13:70i -703 18.
Cancer
19.
8. Barr JR. Elastofibroma. Am J Clin Pathol 1966;45:679-683 9. Kapif PD, Hocken DB, Simpson RHW. Elastofibroma of the hand. J Bone Joint Surg [Br] 1987;69-B:468-469
20.
1974;33:234-238
Hawnaur JM, Jenkins JPR, Isherwood I. Magnetic resonance imaging of musculoaponeurotic fibromatosis. Skeletal Radiol 1990;i9:509-514 Sundaram M, McLeod RA. MR imaging of tumor and tumorlike lesions of bone and soft tissue. AJR 1990;155:817-824 Sundaram M, McGuire MH, Schajowicz F. Soft-tissue masses: histologic basis for decreased signal (short T2) on T2-weighted MR images. AJR
i987;148:1247-1
250
