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EDUCATION EXHIBIT
1477
RadioGraphics
Chest Wall Tumors:
Radiologic Findings
and Pathologic
Correlation
Part 1. Benign Tumors1
ONLINE-ONLY
CME
See www.rsna
.org/education
/rg_cme.html.
LEARNING
OBJECTIVES
After reading this
article and taking
the test, the reader
will be able to:
䡲 Identify the imaging techniques that
are most useful for
localizing and characterizing benign tumors of the chest
wall.
䡲 Describe the characteristic imaging
findings in the most
prevalent benign
chest wall tumors.
䡲 Recognize imaging
signs that facilitate
differential diagnosis
and appropriate
management of benign chest wall tumors.
Ukihide Tateishi, MD, PhD ● Gregory W. Gladish, MD ● Masahiko
Kusumoto, MD, PhD ● Tadashi Hasegawa, MD, PhD ● Ryohei
Yokoyama, MD ● Ryosuke Tsuchiya, MD, PhD ● Noriyuki
Moriyama, MD, PhD
Benign chest wall tumors are uncommon lesions that originate from
blood vessels, nerves, bone, cartilage, or fat. Chest radiography is an
important technique for evaluation of such tumors, especially those
that originate from bone, because it can depict mineralization and thus
indicate the diagnosis. Computed tomography (CT) and magnetic
resonance (MR) imaging are helpful in further delineating the location
and extent of the tumor and in identifying tumor tissues and types. Although the radiologic manifestations of benign and malignant chest
wall tumors frequently overlap, differences in characteristic location
and appearance occasionally allow a differential diagnosis to be made
with confidence. Such features include the presence of mature fat tissue with little or no septation (lipoma), the presence of phleboliths and
characteristic vascular enhancement (cavernous hemangioma), evidence of neural origin combined with a targetlike appearance on MR
images (neurofibroma), well-defined continuity of cortical and medullary bone with the site of origin (osteochondroma), or fusiform expansion and ground-glass matrix (fibrous dysplasia). Both aneurysmal
bone cysts and giant cell tumors typically manifest as expansile osteolytic lesions and occasionally show fluid-fluid levels suggestive of diagnosis.
©
RSNA, 2003
Index terms: Ribs, neoplasms, 471.30 ● Thorax, CT, 470.1211 ● Thorax, MR, 470.12141, 470.12143 ● Thorax, neoplasms, 470.31, 470.36, 470.85
Thorax, radiography, 470.11
RadioGraphics 2003; 23:1477–1490 ● Published online 10.1148/rg.236015526
1From
the Divisions of Diagnostic Radiology (U.T., M.K., N.M.), Pathology (T.H.), Orthopedics (R.Y.), and Thoracic Surgery (R.T.), National
Cancer Center Hospital and Institute, 5-1-1, Tsukiji, Chuo-Ku, 104-0045, Tokyo, Japan; Division of Diagnostic Imaging, M. D. Anderson Cancer
Center, Houston, Tex (G.W.G.); and Division of Orthopedics, National Kyushu Cancer Center, Fukuoka, Japan (R.Y.). Recipient of a Cum Laude
award for an education exhibit at the 2001 RSNA scientific assembly. Received December 20, 2001; revision requested February 22, 2002; final revision received April 22, 2003, and accepted April 25. Supported in part by grant for Scientific Research Expenses for Health and Welfare Programs, the
Foundation for the Promotion of Cancer Research, and 2nd-term Comprehensive 10-year Strategy for Cancer Control. Address correspondence to
U.T. (e-mail: [email protected]).
©
RSNA, 2003
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Table 1
Radiologic Differentiation of Benign Chest Wall Tumors
Imaging Finding
Tumor Type
Attenuation or signal intensity of fat
Calcification
Skeletal
Amorphous contours
Cartilaginous apical cap
Extraskeletal, punctate
Cortical thinning, fluid-fluid levels
Cortical expansion, sclerotic band
Rib erosion, well-defined contours,
extraskeletal location
Location at costochondral junction
Location in paravertebral region
Location in shoulder region
Introduction
Benign chest wall tumors, which may be of vascular, peripheral nerve, osseous, cartilaginous, or
adipose tissue origin, are relatively uncommon,
and few research studies of this group of tumors
have been reported. Radiologic imaging is important in the assessment of these tumors, particularly for determining anatomic origin and extent,
response to therapy, and recurrence (1). Although the imaging features of many of these lesions are nonspecific, the combination of imaging
appearance, location, and clinical information
also may suggest a diagnosis (Tables 1, 2). In this
article, we survey the clinical manifestations and
imaging appearances of the most frequently occurring tumor types, including cavernous hemangioma, glomus tumor, schwannoma, neurofibroma, ganglioneuroma, paraganglioma, osteochondroma, aneurysmal bone cyst, fibrous
dysplasia, ossifying fibromyxoid tumor, chondromyxoid fibroma, lipoma, and spindle cell lipoma.
We describe the imaging techniques that are most
widely used for evaluating and localizing these
tumors and detail the imaging findings common
to tumors of each type, giving particular attention
to findings that may contribute to differential diagnosis.
Lipoma
Fibrous dysplasia
Osteochondroma
Cavernous hemangioma
Aneurysmal bone cyst or giant cell tumor
Ossifying fibromyxoid tumor or chondromyxoid fibroma
Schwannoma or neurofibroma
Osteochondroma
Ganglioneuroma or paraganglioma
Spindle cell lipoma
Overview of Imaging
Techniques and Findings
Benign chest wall tumors typically manifest as
slow-growing, palpable masses in asymptomatic
patients. The slow growth rate that typifies most
benign chest wall tumors is evidenced on radiologic images by well-defined tissue planes and
sometimes by pressure erosions on adjacent bone.
Chest radiography can be used to determine
the location, size, and growth rate of the mass, as
well as to detect calcification, ossification, or bone
involvement (2). However, the high-kilovoltage
radiographic technique used at chest imaging is
not optimal for assessing soft-tissue calcification,
bone, or tumor matrix. The low-kilovoltage technique used for bone radiography can more accurately define soft-tissue planes, particularly in fatcontaining tumors such as lipomas. Low-kilovoltage radiographs also more accurately delineate
calcifications.
Computed tomography (CT) enables more
accurate assessment of tumor morphology, composition, location, and extent (1,3). When used
with contrast material, CT also can provide an
indication of the vascularity of a tumor. When the
relevant anatomy is poorly depicted on axial images—as occurs, for example, in lesions that are
located parallel to the ribs or in the supraclavicular region—the CT scan may be acquired with
an angled gantry or a thin-section breath-hold
technique and multiplanar reformations to clarify
anatomic relationships.
Early adulthood
Early adulthood
Adolescence to
early adulthood
Ganglioneuroma
Paraganglioma
Adulthood
Peripheral nerve
Schwannoma
Neurofibroma
Adulthood
Glomus tumor
Infancy or early
adulthood
Patient Age*
Frequent occurrence of
additional adrenal or
extrathoracic paraganglionic tumors
Mass composed of mature ganglion cells,
Schwann cells, and
nerve fibers
Type 1 neurofibromatosis; infrequent malignant degeneration
Encapsulated, typically
slow-growing lesion
Pain in solitary lesion;
painless multiple lesions
Typically cutaneous mass
of dilated, tortuous,
thin-walled vessels
General
T1-weighted images: low signal
intensity; T2-weighted images:
high signal intensity
T1-weighted images: low signal
intensity; T2-weighted images:
high signal intensity
Calcification (in
25% of patients)
...
T1-weighted images: low signal
intensity; T2-weighted images:
high signal intensity
T1-weighted images: low signal
intensity; T2-weighted images:
high signal intensity
Heterogeneous signal intensity
with areas of high signal intensity on both T1- and T2weighted images; fluid-fluid levels
Heterogeneous signal intensity on
both T1- and T2-weighted images
MR Imaging
Rib erosion; calcification
Bone erosion,
most often in
rib
Bone erosion
Phleboliths
CT
Tateishi et al
(continued)
Well-defined contours and
strong enhancement in
small lesions; nonenhancing central areas of
cystic or necrotic change
in large lesions
Well-defined, plexiform
contours; targetlike appearance; variable enhancement
Well-defined contours;
whorled appearance;
slight enhancement;
location in paravertebral
region
Well-defined contours;
location in midthoracic
region; variable enhancement of center
versus periphery
Well-defined contours;
multiplicity; soft-tissue
mass with feeding vessels; marked enhancement
Ill-defined contours;
marked enhancement
General
Number 6
Rare
Uncommon
Common
Common
Rare
Uncommon
Frequency of
Occurrence
Imaging Findings
●
Vascular
Cavernous hemangioma
Tumor Tissue
and Type
Clinical Findings
Table 2
Clinical and Imaging Findings in Benign Chest Wall Tumors
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Subcutaneous location in
neck or shoulder region; slow growth;
most frequent in men
Deep soft-tissue lesion;
most frequent in the
obese
Location in rib, spine, or
scapula
Location in subchondral
region of flat or tubular
bones
...
Bone fracture or deformity
...
Bone fracture or deformity
General
NA
Attenuation of fat;
slightly enhancing septa
Sclerotic band
Sclerotic band,
osteolytic
change
Cortical thinning
Amorphous calcification
Cortical thinning
Cartilaginous cap
CT
T1-weighted images: high signal
intensity (low-signal-intensity
septa); T2-weighted images:
high signal intensity
T1-weighted images: low signal
intensity; T2-weighted images:
high signal intensity
T1-weighted images: low signal
intensity; T2-weighted images:
high signal intensity; fluid-fluid
levels (less common than in aneurysmal bone cyst)
T2-weighted images: high signal
intensity
Heterogeneous signal intensity on
both T1- and T2-weighted images; fluid-fluid levels
Heterogeneous signal intensity on
both T1- and T2-weighted images
T2-weighted images: high signal
intensity
Cap; T2-weighted images: high
signal intensity
MR Imaging
Well-defined contours;
internal homogeneity
and no enhancement
unless septa are present
Well-defined contours;
internally heterogeneous
Expansile; diffuse or heterogeneous enhancement
Confluent contours; vascularity; heterogeneous
enhancement
Eccentric growth; usually
solitary but may occur in
multiples
Fusiform; monostotic or
polyostotic involvement
Eccentric growth pattern;
location at costochondral junction
Expansile blood-filled cyst
General
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*Typical patient age at diagnosis.
Uncommon
Common
Adulthood
Adulthood
Rare
Early adulthood
Common
Rare
Uncommon
Uncommon
Common
Frequency of
Occurrence
Imaging Findings
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Spindle cell lipoma
Chondromyxoid
fibroma
Adipose
Lipoma
Giant cell tumor
Early to middle
adulthood
Adolescence to
early adulthood
Adulthood
Fibrous dysplasia
Ossifying fibromyxoid tumor
Early adulthood
Adulthood
Patient Age*
Aneurysmal
bone cyst
Osseous and cartilaginous
Osteochondroma
Tumor Tissue
and Type
Clinical Findings
Table 2
Clinical and Imaging Findings in Benign Chest Wall Tumors
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Figure 1. Cavernous hemangioma in a 46-year-old man. (a) Axial T1-weighted (repetition time msec/echo time msec ⫽ 600/12) magnetic resonance (MR) image obtained with a
surface coil at the level of the liver (L) shows an ill-defined soft-tissue mass in the right chest
wall. The tumor appears as an area of heterogeneous hyperintense signal relative to the signal
intensity of adjacent muscle (arrows). (b) Axial gadolinium-enhanced T1-weighted (600/12)
fat-suppressed MR image shows heterogeneous enhancement and distended vessels (arrow)
in the tumor.
Magnetic resonance (MR) imaging is the preferred modality for the evaluation of chest wall
tumors. The superior spatial resolution afforded
by MR imaging with the administration of contrast material often enables accurate characterization of the tumor tissue and extent, including differentiation from adjacent areas of inflammation.
Meticulous attention to technique is necessary for
optimal MR imaging. Standard spin-echo and
fast spin-echo sequences are satisfactory for most
evaluations, but the use of peripheral cardiac gating and respiratory compensation can reduce motion artifacts that often degrade MR images of the
thorax. Prone positioning of the patient can lessen
the occurrence of respiratory artifacts on images
of anterior chest wall tumors. Surface coils are
useful for obtaining detailed images of superficial
chest wall lesions, whereas a dedicated torso coil
should be used to optimize image quality for tumors with greater intrathoracic extent.
Vascular Tumors
Cavernous Hemangioma
Cavernous hemangiomas, which are among the
least common benign chest wall masses, consist of
dilated, tortuous, thin-walled vessels. They are
typically cutaneous in location, large, and poorly
circumscribed, and they can be locally destructive. Noncutaneous location is uncommon, with a
reported frequency of 0.8% among all benign vascular lesions (4) (Fig 1).
Cavernous hemangiomas typically manifest at
birth or before the age of 30 years. Plain chest
radiographs may show a soft-tissue mass, which
occasionally is associated with pressure erosion on
adjacent bone. CT is more sensitive than plain
radiography in detecting phleboliths, which are
present in approximately 30% of cavernous hemangiomas (5). CT scans show a soft-tissue mass
with heterogeneous low levels of attenuation due
to the fatty, fibrous, and vascular tissue elements
of the mass. T1- and T2-weighted MR images
typically reveal areas of high signal intensity in the
mass. On T1-weighted images, intramuscular
cavernous hemangiomas manifest as poorly marginated masses with signal intensity similar to that
of skeletal muscle. Wispy or coarse linear areas of
high signal intensity are common and thought to
be caused in part by the presence of stagnant
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blood in cavernous or cystic spaces. On T2weighted images, these tumors are well marginated and have high signal intensity compared with
that of subcutaneous fat. Signal intensity voids
caused by rapidly flowing blood also can be seen
(6,7).
Glomus Tumor
Glomus tumors consist of neoplastic cells that
closely resemble the smooth muscle cells of the
normal glomus body. They typically occur in
adulthood, with equal frequency in men and
women, and manifest clinically as solitary, painful
masses (8). Multiple tumors are uncommon and
are more likely to be asymptomatic. An intramuscular location is common (Fig 2). Benign glomus
tumors outnumber malignant ones by a sizable
margin. Chest radiographs and CT scans may
show a soft-tissue mass with erosion of adjacent
bone. In typical cases, MR images reveal a tumor
that displaces major vessels and is encircled by
tortuous vessels arborizing from a vascular pedicle
(9,10). The mass is usually heterogeneous in signal intensity and sharply delineated from adjacent
soft tissue after intravenous administration of
gadolinium-based contrast material (9).
Figure 2. Glomus tumor in a 61-year-old man. Coronal gadolinium-enhanced T1-weighted (570/12) MR
image at the level of the tracheal bifurcation (T) shows
multiple enhancing masses (arrows) with ill-defined
margins in the chest wall.
Peripheral Nerve Tumors
Schwannoma
Schwannomas, also known as neurilemomas or
neurinomas, are encapsulated neoplasms that
originate in nerve sheaths and are usually slow
growing. Chest wall schwannomas arise from spinal nerve roots and intercostal nerves and typically occur in patients between 20 and 50 years of
age. Small tumors tend to be spheroid, firm, and
well circumscribed (Fig 3), whereas larger tumors
are ovoid or irregularly lobulated. Schwannomas
occasionally manifest as fibrous-walled cysts containing smaller solid nodules. Radiographs do not
usually depict small schwannomas, but bone erosion or scalloping can occasionally be seen. Nonenhanced CT scans of schwannoma typically
show a well-circumscribed homogeneous mass
with attenuation slightly less than or equal to that
of muscle. On CT scans acquired after contrast
material administration, the attenuation of the
mass is equal to or slightly greater than that of
muscle, and any cystic or necrotic areas in the
Figure 3. Schwannoma in a 43-year-old man.
Axial nonenhanced CT scan of the right side of
the chest wall depicts an extrapleural nodule that
originated from intercostal soft tissue along the
course of an intercostal nerve. The presence of
heterogeneous attenuation (arrowhead) indicates
myxoid degeneration, which is found occasionally in small lesions like this one.
mass appear nonenhanced. The signal intensity of
schwannoma on T1-weighted MR images is equal
to or slightly greater than that of muscle and on
T2-weighted images is markedly greater, with
increased contrast between the high-signal-intensity nerve sheath tumor, intermediate-signal-intensity fat, and low-signal-intensity muscle (11).
The nerve from which the tumor originated can
often be seen along one side of the mass. Small
tumors tend to enhance brightly and uniformly
after intravenous administration of contrast material, whereas the enhancement pattern of larger
lesions may be more heterogeneous because of
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treme pain that often accompanies percutaneous
biopsy is further evidence of the neural origins of
the tumor.
Neurofibroma
Figure 4. Neurofibroma in a 26-year-old man with
type 1 neurofibromatosis. Coronal T2-weighted
(6,000/112) MR image of the thoracic inlet shows intraforaminal and perineural extension of a tumor (arrows) that has a targetlike appearance (ie, a center with
signal intensity lower than that in the periphery).
Neurofibromas are slow-growing neoplasms that
originate from a nerve, may or may not be encapsulated, and may include components of cystic
degeneration and calcification. Neurofibromas
develop most commonly in patients between the
ages of 20 and 30 years, in men and women
equally. In 60%–90% of affected patients, the
diagnosis is either type 1 neurofibromatosis or
multiple plexiform neurofibromas. Malignant
degeneration occasionally occurs in these lesions,
but the risk is low.
Radiographs of the spine may show a widening
of neural foramina because of tumor extension
along spinal nerve roots. Most neurofibromas are
hypoattenuated on nonenhanced CT scans and
show heterogeneous enhancement after intravenous administration of contrast material. Many
neurofibromas have a histologic pattern of zonal
distinction, with a central zone composed of a
highly cellular component and a peripheral zone
composed of abundant stromal material, which
results in a targetlike appearance on T2-weighted
MR images. On these images, the mass is characterized by a rim of increased signal intensity that
surrounds the central part of the tumor, which
has a lower signal intensity (Fig 4). This sign is
also evident on gadolinium-enhanced MR images, on which the central part of the tumor appears markedly enhanced (12).
Ganglioneuroma
Figure 5. Ganglioneuroma in an asymptomatic 57year-old woman. (a) Axial T2-weighted (6,000/112)
MR image of the left ventricle (LV) shows curvilinear
areas of low signal intensity (arrowheads) in the tumor,
which give it a septated appearance. The tumor had a
broad base and was attached to several vertebral bodies. (b) Photograph of the cut surface of the resected
specimen shows fibrous septa (arrowheads) that correspond to the curvilinear areas of low signal intensity on
the T2-weighted MR image.
central cystic change. The presence of bone erosion without destruction indicates the benign nature and slow growth rate of this lesion. The ex-
Ganglioneuromas originate from the sympathetic
ganglia in the chest wall. Although this tumor
most often arises de novo in young adults, it also
may occur as a maturation of neuroblastoma.
The mass is composed of mature ganglion cells,
Schwann cells, and nerve fibers, and it is often
large and encapsulated, with delicate trabeculation. Ganglioneuromas usually manifest radiologically as ovoid, sharply marginated paravertebral masses. Calcification occurs in 25% of cases.
The tumor has either homogeneous or heterogeneous attenuation on CT images and homogeneous intermediate signal intensity on both T1and T2-weighted MR images. Curvilinear bands
of low signal intensity are seen on both T1- and
T2-weighted images, giving the lesion a whorled
appearance (13) (Fig 5).
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Figure 7. Osteochondroma in a 39-year-old woman. (a) Axial contrast-enhanced CT scan at the level of the left
atrium (A) shows a dense calcification (arrowhead) that projects medially from a right rib. (b) Axial T2-weighted
(6,000/112) MR image of the right side of the chest wall obtained with a surface coil shows a cartilaginous apical cap
(arrow), which has a slightly higher signal intensity than does muscle.
Paraganglioma
Paragangliomas arise either in the aorticopulmonary paraganglia or in the aorticosympathetic
paraganglia in the paravertebral region. They are
typically located in the middle thorax, adjacent to
the fifth, sixth, or seventh rib, with a right-sided
predominance. Most paragangliomas occur in
adolescents and young adults (Fig 6). On MR
images, the tumors show homogeneous signal
intensity and marked enhancement after intravenous injection of contrast material (14). Many
patients with paragangliomas also have adrenal or
extrathoracic paraganglionic tumors that manifest
either synchronously or metachronously.
Osseous and Cartilaginous Tumors
Osteochondroma
Osteochondromas are relatively common skeletal
lesions that originate from the aberrant growth of
normal tissue. In the ribs, these tumors occur
with particular frequency at the costochondral
junction. The tumors are characteristically pedunculated osseous protuberances arising from
Figure 6. Paraganglioma in a 23-year-old man. Coronal reformatted image from a contrast-enhanced
multidetector CT study of the thoracic spine shows an
extrapleural spindle-shaped mass (M) with relatively
homogeneous attenuation in the left paravertebral region. The apparently noninvasive well-demarcated
mass was discovered at resection to be attached to the
sympathetic nerve (arrow).
the surface of the parent bone. Radiographs may
show a cap composed of hyaline cartilage, which,
if it is calcified, may be more optimally visualized
at CT. The cartilaginous tissue in the cap is of
high signal intensity on T2-weighted MR images
(Fig 7). Continuity between the lesion and corti-
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Figure 8. Aneurysmal bone cyst in a 54-year-old
woman. (a) Nonenhanced CT scan at the level of the
clavicle (C) shows an expansile lytic mass (M) in the
medial left area of the clavicle. The mass is not well
differentiated from the overlying muscle. (b) Axial T2weighted (6,000/112) MR image shows a mass with
overall signal intensity higher than that of fat. The mass
contains regions with the signal intensity of fluid (arrow), as well as multiple septa with low signal intensity
(arrowheads). (c) Photomicrograph (original magnification, ⫻100; hematoxylin-eosin stain) shows osteoclast-like giant cells and fibroblasts with blood-filled
spaces (arrows) that account for the fluid-fluid level
seen on MR images.
cal or medullary bone in the extremities can be
detected with CT or MR imaging (15,16) but is
not often apparent on images of the ribs. Complications associated with this tumor include fractures, osseous deformity, vascular injury, neural
compression, bursa formation, and malignant
transformation. Pain at the lesion site, as well as
bone erosion, irregular calcification, or thickening
of the cartilage cap depicted on radiologic images,
indicate malignant transformation.
Aneurysmal Bone Cyst
Aneurysmal bone cysts are unusual benign
masses that have the potential for rapid growth,
bone destruction, and extension into adjacent soft
tissue. The masses contain a network of multiple blood-filled cysts lined by fibroblasts and
multinucleated giant cells of the osteoclast type.
Although a sclerotic margin around the lesion
may indicate that it is benign, soft-tissue extension can make it difficult to differentiate aneurysmal bone cyst from sarcoma. Most aneurysmal
bone cysts occur in patients under the age of 30
years. In the chest wall, the most common sites of
involvement are the posterior elements of the
spine (eg, articular process, lamina, and spinous
process).
Radiographs show an expansile lesion with a
well-defined inner margin. CT is useful in delineating the size and location of the intraosseous
and extraosseous components of the tumor. MR
images typically show a lobulated or septated
mass with a thin, well-defined rim of low signal
intensity (Fig 8) (17,18). The detection of a fluidfluid level within the tumor indicates the hemorrhagic nature of the cyst contents; however, fluidfluid levels also may be found in other osseous
lesions, including giant cell tumor, simple bone
cyst, and chondroblastoma (19,20).
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Figure 9. Fibrous dysplasia of bone in a 28-year-old man. (a) Axial nonenhanced CT scan at the level of the
pulmonary artery (P) shows an expansile mass (M) with areas of ground-glass attenuation in a left rib that indicate mineralization. (b) Axial T2-weighted (5,000/120) MR image shows heterogeneous signal intensity in the
tumor (arrow). (c) Photograph of the cut surface of a resected rib specimen reveals a dense fibrous lesion (L)
that has not invaded the surrounding structures. (d) High-power photomicrograph (original magnification,
⫻100; hematoxylin-eosin stain) shows immature osteoblasts and osteoid formation (arrowheads).
Fibrous Dysplasia of Bone
Fibrous dysplasia is a skeletal developmental
anomaly in which mesenchymal osteoblasts fail to
undergo normal morphologic differentiation and
maturation. Approximately 70%– 80% of cases
are monostotic and 20%–30% are polyostotic.
The age range of patients with monostotic disease
is 10 –70 years, but recognition is most frequent
at 20 –30 years of age. Patients are usually asymptomatic, although pathologic fracture resulting
from fibrous dysplasia can cause pain. The ribs
are commonly affected, and the clavicle is occasionally involved. Radiographs characteristically
show unilateral fusiform enlargement and deformity with cortical thickening and increased trabeculation of one or more ribs. Amorphous or irregular calcification is often seen in the lesion on
CT scans. MR imaging is useful in accurately defining the full extent of the lesion. The signal intensity varies from low to high on T2-weighted
images but typically is low in areas of lesion involvement on T1-weighted images (21–23) (Fig
9). Monostotic disease does not usually progress
to polyostotic disease, and the size and number of
lesions generally remain the same over time as
they were at initial radiologic evaluation. Although malignant transformation also is rare, osteosarcoma or fibrosarcoma may develop after
irradiation of the involved bones.
Ossifying Fibromyxoid Tumor
Ossifying fibromyxoid tumor is a rare neoplasm of
uncertain origin that most often occurs in the
ribs. Tumors consist of well-vascularized fibrous
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Figure 10. Ossifying fibromyxoid tumor in a 32-year-old man. (a) Axial T2-weighted (4,500/160) MR image at
the level of the stomach (S) shows a well-defined mass with multiple septa and an overall signal intensity higher than
that of muscle, as well as a focal nodule of relatively low signal intensity (arrow). (b) Photograph of a resected specimen reveals myxoid components (white areas) separated by bands of fibrous tissue (arrowheads), as well as a softtissue nodule (arrow) that corresponds to the low-signal-intensity area seen on MR images. (c) Photomicrograph
(original magnification, ⫻100; hematoxylin-eosin stain) shows the trabecular or lacy arrangement of tumor cells in
the myxoid matrix, with areas of marked ossification (arrow) that exhibited low signal intensity on MR images.
Giant Cell Tumor
stromata containing trabeculae of new bone and
multinucleated giant cells (24) and may occur
singly or in multiples. Tumors appear on plain
radiographs as elongated, bubble-shaped areas of
intracortical osteolysis surrounded by a band of
sclerotic tissue. Although they are usually stable
in size, spontaneous regression and progression
have been reported. On T2-weighted MR images,
tumors manifest as focal areas of high signal intensity corresponding to that of myxoid material
(25) (Fig 10). The vascularity of these tumors is
apparent from their characteristic enhancement
after the administration of contrast material.
Giant cell tumors are relatively common benign
skeletal lesions of uncertain origin. These tumors
consist of vascular sinuses that are lined or filled
with abundant giant cells and spindle cells. Giant
cell tumors are typically solitary but also may occur simultaneously or metachronously in multiples. The tumors typically manifest at age
21– 40 years, after closure of the epiphyses, and
are more common in women than in men. Thoracic giant cell tumors often arise in subchondral
regions of the flat and tubular bones of the chest
wall, including the sternum, clavicle, and ribs.
Plain radiographs of these tumors show eccentric
osteolytic lesions accompanied by cortical thinning and expansion. CT allows evaluation of the
extent of the tumor and its relationship to surrounding structures. Tumors typically have a long
relaxation time at T1- and T2-weighted MR imaging and appear as areas of low signal intensity
on T1-weighted images and high signal intensity
on T2-weighted images (Fig 11). Fluid-fluid levels are less commonly seen in these tumors than
in aneurysmal bone cysts (26 –29).
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Chondromyxoid Fibroma
Chondromyxoid fibromas, the least common benign cartilaginous neoplasms, consist of varying
proportions of chondroid, myxomatous, and fibrous components arranged in lobules that are
separated by vascular sclerotic bands. Chondromyxoid fibromas typically occur in patients who
are less than 30 years of age. They are relatively
rare in the chest wall and occasionally occur in
the ribs, spine, or scapulae. On plain radiographs,
chondromyxoid fibromas usually appear as wellmarginated masses with scalloped sclerotic borders and no internal calcification. Cortical expansion, exuberant endosteal sclerosis, and overlapping areas of cortical scalloping also may be
present, giving the impression of coarse trabeculation. Chondromyxoid fibromas have heterogeneous signal intensity on T2-weighted MR images and diffuse enhancement on T1-weighted
images acquired after intravenous administration
of contrast material (30,31) (Fig 12).
Adipose Tissue Tumors
Lipoma
Lipomas are well-circumscribed encapsulated
masses composed of adipocytes that differ very
little from normal fatty tissue. They typically occur in patients who are 50 –70 years of age, and
they are most frequent in the obese. Most lipomas
that originate in the chest wall are deep lipomas,
which tend to be larger and less well circumscribed than superficial lesions (32). On CT and
MR images, lipomas generally appear to be internally homogeneous and do not enhance after intravenous contrast material administration (Fig
13). However, multiple thin septa often are
present that appear slightly enhanced on CT
scans and have low signal intensity on fat-suppressed T1-weighted MR images.
Spindle Cell Lipoma
Spindle cell lipoma is a rare, painless, and slowgrowing neoplasm in which mature fat cells are
replaced by collagen-forming spindle cells. The
tumor usually manifests as a solitary well-demarcated 3–5-cm mass confined to the subcutaneous
tissues of the neck or shoulder region in men
older than 45 years of age (32,33). On both T1and T2-weighted MR images, it appears as a heterogeneous mass with lipomatous and nonlipomatous components of various quantities
(Fig 14).
Figure 11. Giant cell tumor in a 54-year-old woman.
(a) Sagittal T2-weighted (6,000/112) MR image of the
ribs (R) shows a mass (M) with overall signal intensity
higher than that of muscle but with small foci of low
signal intensity in the periphery. (b) Photograph of a
resected specimen shows extensive vascular channels
(arrows) that correspond to areas of low signal intensity
on MR images.
Conclusions
Benign chest wall tumors are a diverse group of
lesions with vascular, neural, osseous, cartilaginous, or lipomatous origins. Radiologic assessment is an essential component of the management of these tumors and usually includes the use
of chest radiography to detect and localize the
lesion and of cross-sectional CT and MR imaging
to further characterize the lesion and define its
extent. Radiologic findings indicative of a benign
tumor (eg, presence of a well-defined mass without infiltration of adjacent structures, or presence
of bone erosion without destruction) and clinical
features such as slow growth and lack of pain support a relatively conservative management strategy. Occasionally, benign tumors may have imaging features that are specific enough to enable
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Figure 12. Chondromyxoid fibroma in a 56-year-old woman. (a) Axial T2-weighted (6,000/112) MR image at the
level of the liver (L) shows a mass in the lateral part of the chest wall. The mass has an overall signal intensity higher
than that of fat, but multiple septa (arrow) with lower signal intensity also are visible in the tumor. (b) Photomicrograph (original magnification, ⫻100; hematoxylin-eosin stain) reveals fibroblasts intermingled with interstitial myxoid material that accounts for the high signal intensity on T2-weighted MR images.
Figure 13. Lipoma in a 42-year-old woman.
Axial contrast-enhanced CT scan at the level of
the pulmonary artery (P) shows a well-defined
mass with the same attenuation as fat in the left
part of the chest wall. Soft-tissue septa (arrows)
are clearly visible at the periphery of the mass.
Septa not only occur in benign lipomas but also
are common in atypical lipomatous tumors and
liposarcomas.
immediate diagnosis and initiation of appropriate
management. Such features include the presence
of mature fatty tissue with little or no septation
(lipoma), the presence of phleboliths and characteristic vascular enhancement (cavernous hemangioma), and evidence of neural origin combined
with a targetlike appearance on MR images (neurofibroma). Several primary bone tumors also
Figure 14. Spindle cell lipoma in a 72-year-old
man. Axial gadolinium-enhanced T1-weighted
(500/15) MR image at the level of the spleen
(SP) and stomach (ST) reveals a nodule (arrow)
with heterogeneous enhancement in the subcutaneous tissues of the back. The fat component in
this tumor is hard to identify on MR images.
may have characteristic features that allow confident identification, such as well-defined cortical
and medullary continuity with the bone of origin
(osteochondroma) or fusiform expansion and
ground-glass matrix (fibrous dysplasia). Both aneurysmal bone cysts and giant cell tumors typically manifest as expansile osteolytic lesions and
occasionally show fluid-fluid levels suggestive of
diagnosis. However, many chest wall tumors have
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nonspecific imaging features, and histologic analysis of tissue specimens is frequently required for
diagnosis. Even after the decision has been made
to perform a biopsy, imaging continues to play an
important role in tumor management and is frequently used to facilitate biopsy, assess postprocedural complications, and perform follow-up
evaluation of tumors that are not excised.
16.
17.
18.
References
1. Jeung MY, Gangi A, Gasser B, et al. Imaging of
chest wall disorders. RadioGraphics 1999;
19:617– 637.
2. Siegel MJ. Magnetic resonance imaging of musculoskeletal soft tissue masses. Radiol Clin North
Am 2001; 39:701–720.
3. Athanassiadi K, Kalavrouziotis G, Rondogianni
D, Loutsidis A, Hatzimichalis A, Bellenis I. Primary chest wall tumors: early and long-term results of surgical treatment. Eur J Cardiothorac
Surg 2001; 19:589 –593.
4. Enzinger FM, Weiss SW. Benign tumors and tumorlike lesions of blood vessels. In: Enzinger FM,
Weiss SW, eds. Soft tissue tumors. 3rd ed. St
Louis, Mo: Mosby, 1995; 579 – 626.
5. Levine E, Wetzel LH, Neff JR. MR imaging and
CT of extrahepatic cavernous hemangiomas. AJR
Am J Roentgenol 1986; 147:1299 –1304.
6. Kaplan PA, Williams SM. Mucocutaneous and
peripheral soft-tissue hemangiomas: MR imaging.
Radiology 1987; 163:163–166.
7. Cohen EK, Kressel HY, Perosio T, et al. MR imaging of soft-tissue hemangiomas: correlation with
pathologic findings. AJR Am J Roentgenol 1988;
150:1079 –1081.
8. Enzinger FM, Weiss SW. Perivascular tumors. In:
Enzinger FM, Weiss SW, eds. Soft tissue tumors.
3rd ed. St Louis, Mo: Mosby, 1995; 701–733.
9. Kneeland JB, Middleton WD, Matloub HS, Jesmanowicz A, Froncisz W, Hyde JS. High resolution MR imaging of glomus tumor. J Comput Assist Tomogr 1987; 11:351–352.
10. Schneller J. Multifocal glomangiomyomas in the
chest wall of a young man. Arch Pathol Lab Med
2001; 125:1146 –1147.
11. Suh JS, Abenoza P, Galloway HR, Everson LI,
Griffiths HJ. Peripheral (extracranial) nerve tumors: correlation of MR imaging and histologic
findings. Radiology 1992; 183:341–346.
12. Burk DL Jr, Brunberg JA, Kanal E, Latchaw RE,
Wolf GL. Spinal and paraspinal neurofibromatosis: surface coil MR imaging at 1.5 T. Radiology
1987; 162:797– 801.
13. Zhang Y, Nishimura H, Kato S, et al. MRI of ganglioneuroma: histologic correlation study. J Comput Assist Tomogr 2001; 25:617– 623.
14. Flickinger FW, Yuh WT, Behrendt DM. Magnetic resonance imaging of mediastinal paraganglioma. Chest 1988; 94:652– 654.
15. Cohen EK, Kressel HY, Frank TS, et al. Hyaline
cartilage-origin bone and soft-tissue neoplasms:
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
●
Number 6
MR appearance and histologic correlation. Radiology 1988; 167:477– 481.
Murphey MD, Choi JJ, Kransdorf MJ, Flemming
DJ, Gannon FH. Imaging of osteochondroma: variants and complications with radiologic-pathologic
correlation. RadioGraphics 2000; 20:1407–1434.
Beltran J, Simon DC, Levy M, Herman L, Weis L,
Mueller CF. Aneurysmal bone cysts: MR imaging
at 1.5 T. Radiology 1986; 158:689 – 690.
Zimmer WD, Berquist TH, Sim FH, et al. Magnetic resonance imaging of aneurysmal bone cyst.
Mayo Clin Proc 1984; 59:633– 636.
Hudson TM. Fluid levels in aneurysmal bone
cysts: a CT feature. AJR Am J Roentgenol 1984;
142:1001–1004.
Hudson TM, Hamlin DJ, Fitzsimmons JR. Magnetic resonance imaging of fluid levels in an aneurysmal bone cyst and in anticoagulated human
blood. Skeletal Radiol 1985; 13:267–270.
Utz JA, Kransdorf MJ, Jelinek JS, Moser RP Jr,
Berrey BH. MR appearance of fibrous dysplasia.
J Comput Assist Tomogr 1989; 13:845– 851.
Kransdorf MJ, Moser RP Jr, Gilkey FW. Fibrous
dysplasia. RadioGraphics 1990; 10:519 –537.
Jee WH, Choi KH, Choe BY, Park JM, Shinn KS.
Fibrous dysplasia: MR imaging characteristics
with radiopathologic correlation. AJR Am J Roentgenol 1996; 167:1523–1527.
Enzinger FM, Weiss SW, Liang CY. Ossifying
fibromyxoid tumor of soft parts: a clinicopathological analysis of 59 cases. Am J Surg Pathol
1989; 13:817– 827.
Schaffler G, Raith J, Ranner G, Weybora W, Jeserschek R. Radiographic appearance of an ossifying
fibromyxoid tumor of soft parts. Skeletal Radiol
1997; 26:615– 618.
Cooper KL, Beabout JW, Dahlin DC. Giant cell
tumor: ossification in soft-tissue implants. Radiology 1984; 153:597– 602.
Dahlin DC. Caldwell Lecture. Giant cell tumor of
bone: highlights of 407 cases. AJR Am J Roentgenol 1985; 144:955–960.
Murphey MD, Nomikos GC, Flemming DJ, Gannon FH, Temple HT, Kransdorf MJ. Imaging of
giant cell tumor and giant cell reparative granuloma of bone: radiologic-pathologic correlation.
RadioGraphics 2001; 21:1283–1309.
Lee MJ, Sallomi DF, Munk PL, et al. Pictorial
review: giant cell tumours of bone. Clin Radiol
1998; 53:481– 489.
Feldman F, Hecht HL, Johnston AD. Chondromyxoid fibroma of bone. Radiology 1970; 94:
249 –260.
Wilson AJ, Kyriakos M, Ackerman LV. Chondromyxoid fibroma: radiographic appearance in 38
cases and in a review of the literature. Radiology
1991; 179:513–518.
Haas AF, Fromer ES, Bricca GM. Spindle cell
lipoma of the scalp: a case report and review. Dermatol Surg 1999; 25:68 –71.
Mehregan DR, Mehregan DA, Mehregan AH,
Dorman MA, Cohen E. Spindle cell lipomas: a
report of two cases— one with multiple lesions.
Dermatol Surg 1995; 21:796 –798.
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