chest wall mass

W460 AJR:197, September 2011

PET/CTFDG activity provides information re-

garding the metabolic status of chest wall masses but only limited additional diagnos-tic information regarding the primary lesion. It is most useful in providing data on region-al and distant metastases and in choosing the most metabolically active area for biopsy.

Imaging-Guided BiopsyChest wall lesions are usually amenable

to imaging-guided percutaneous biopsy with CT or ultrasound. Review of CT, MRI, and PET/CT findings allows the percutaneous ap-proach to be formulated. Directing biopsy to-ward areas of enhancing or metabolically ac-tive soft tissue within the lesion will avoid an inadequate specimen resulting from tumor necrosis. PET/CT can be particularly helpful in confirming areas of viable tumor with FDG uptake in a large chest wall lesion or nodal metastases, which may be easier to access.

Scenario 1Clinical History

A 76-year-old man with a remote history of aortic and mitral valve replacement presented with acute left chest wall pain. There was no his-tory of significant trauma. ECG showed no evi-dence of an acute myocardial event. On clinical examination, the patient had pain, tenderness, and swelling in the left anterolateral chest wall. There were no systemic symptoms or history of fever, and serum WBC count was normal. A chest radiograph and MRI were obtained.

Radiology of Chest Wall Masses

Charles P. Mullan1

Rachna Madan2

Beatrice Trotman-Dickenson2

Xiaohua Qian3

Francine L. Jacobson2

Andetta Hunsaker2

Mullan CP, Madan R, Trotman-Dickenson B, Qian X, Jacobson FL, Hunsaker A

1Department of Radiology, Altnagelvin Hospital, Londonderry BT46 5QR, Northern Ireland. Address correspondence to C. P. Mullan ([email protected]).

2Department of Radiology, Brigham & Women’s Hospital, Boston, MA.

3Department of Pathology, Brigham & Women’s Hospital, Boston, MA.

Cardiopulmonar y Imaging • Review

CMEThis article is available for CME credit.See www.arrs.org for more information.

WEB This is a Web exclusive article.

AJR 2011; 197:W460–W470

0361–803X/11/1973–W460

© American Roentgen Ray Society

Choosing an Imaging TechniqueRadiography

Chest radiographs and dedicated views of the ribs and sternoclavicular joints provide basic information regarding the site of the lesion and reveal osseous changes. Radio-graphs are especially useful in the setting of trauma, infection, and osseous tumors.

UltrasoundSuperficial chest wall lesions can be char-

acterized with ultrasound imaging, and these lesions are amenable to biopsy with ultra-sound guidance.

CTCT is the workhorse of diagnostic imag-

ing for chest wall lesions and provides good spatial resolution, including depiction of os-seous and soft-tissue structures. MDCT en-ables imaging of a large tissue volume in a short acquisition time, reducing the effect of respiratory motion in the thorax. CT reveals mineralization and bony involvement and helps in narrowing the differential diagnosis.

MRIMRI has superior soft-tissue resolution

and is invaluable for local assessment of pri-mary tumors. It enables accurate tissue char-acterization and assessment of enhancement patterns. It plays a key role in preoperative staging to assess for multispatial and multi-compartment involvement and involvement of neurovascular structures.

Keywords: biopsy, cardiopulmonary imaging, CT, MRI, PET/CT, thorax

DOI:10.2214/AJR.10.7259

Received July 6, 2010; accepted after revision October 4, 2010.

OBJECTIVE. The purpose of this article is to highlight the role of radiography, CT, PET/CT, and MRI in the diagnosis and management of chest wall lesions. Chest wall masses are caused by a spectrum of clinical entities. The lesions highlighted in this selection of case sce-narios include neoplastic, inflammatory, and vascular lesions.

CONCLUSION. Imaging evaluation with radiography, CT, MRI, and PET/CT plays an important role in the accurate diagnosis of chest wall lesions. It can also facilitate percutane-ous biopsy, when it is indicated. Imaging enables accurate staging and is a key component of treatment planning for chest wall masses.

Mullan et al.Imaging of Chest Wall Masses

Cardiopulmonary ImagingReview

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AJR:197, September 2011 W461

Imaging of Chest Wall Masses

Description of ImagesThe chest radiograph (Fig. 1A) shows ev-

idence of cardiomegaly, left atrial enlarge-ment, and prior sternotomy, consistent with a history of valvular heart disease. There is diffuse opacity overlying the left lateral chest wall and axilla. Figure 1B is a sagittal T2-weighted image from the MRI study of the thorax showing a large well-defined le-sion in the left anterolateral chest wall con-taining high-signal material, with layering of intermediate-to-high-signal material in the dependent portion. There is also dif-fusely increased signal intensity in the left pectoralis major muscle, extending across the anterior chest wall. Figure 1C shows low signal within the anterior portion of the lesion on axial T1-weighted imaging and intermediate-to-high signal in the de-pendent portion. An axial STIR image (Fig. 1D) confirms that the lesion contains fluid, and diffuse high signal in the left pectoralis major muscle and adjacent fat are consistent with inflammatory change.

Differential DiagnosisThe most likely diagnosis is a hemato-

ma, consistent with the acute onset of the pain and location within the chest wall mus-culature. The patient has prosthetic cardiac valves and was therefore receiving oral an-ticoagulants. A relatively minor muscle inju-ry could precipitate a significant hematoma. Although, to our knowledge, there are lim-ited published data about spontaneous chest wall bleeding, hematoma in the thoracic wall is a described complication in patients receiving anticoagulants who undergo tho-racic or shoulder surgery [1]. The fluid-fluid level within the lesion on MRI is consistent with layering of hemorrhage, with the more-dependent hemorrhagic contents showing higher signal on T1-weighted imaging. The increased T2-weighted signal extending across the left pectoralis muscle is sugges-tive of pectoralis muscle injury and tear. A chest wall abscess would also be consistent with the presentation of chest pain. Howev-er, an infective lesion of this size would be

expected to cause systemic symptoms, in-cluding fever, which were absent in this case. Although the MRI scans reveal a large fluid collection with inflammatory change in adja-cent tissues, the lack of a discernible wall is consistent with hematoma rather than an ab-scess. The history of acute chest pain does not suggest a primary neoplastic process, but hemorrhage occurring within a tumor could cause these features. Hemorrhage may occur in soft-tissue metastases, such as those sec-ondary to melanoma. However, the lack of a solid component within the lesion makes this diagnosis unlikely. A primary tumor in this region would most likely be a rhabdomyo-sarcoma arising in the left pectoralis major muscle. The appearance of the lesion in this case is unusual for rhabdomyosarcoma.

Diagnosis: Chest Wall HematomaThe diagnosis of chest wall hematoma in

this case is suggested by the acute clinical presentation and the patient’s valvular heart disease requiring anticoagulants. The patient

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Fig. 1—76-year-old man with acute left chest wall pain.A, Posteroanterior chest radiograph.B, Sagittal T2-weighted image of thorax.C, Axial T1-weighted image of thorax.D, Axial STIR image of thorax.

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Mullan et al.

had an international normalized ratio of 3.0 and a low hematocrit on admission. The use of cross-sectional imaging with CT or MRI enables the lesion to be localized within the pectoralis major muscle, helping to define the differential diagnosis. If there is clini-cal concern of an abscess or an underlying chest wall neoplasm, the use of IV contrast agent should be considered. The presence of an enhancing soft-tissue component is not an expected feature of acute chest wall hema-toma and should raise suspicion of hemor-rhage within a neoplastic lesion. Granulation tissue surrounding an abscess often exhibits enhancement. Mild wall enhancement may be seen in chronic hematomas [2].

Reversal of anticoagulation therapy in this patient with prosthetic cardiac valves could precipitate a thromboembolic event, but tem-porary reversal may be required before under-taking a drainage procedure. A hematoma of this size would require a prolonged period to resolve with conservative measures. As well as causing patient discomfort and localized mass effect on the adjacent structures in the chest wall, there is a significant risk that the hematoma will become infected. The superfi-cial location of the lesion makes it suitable for imaging-guided percutaneous drainage with ultrasound. Surgical evacuation would be more invasive and would expose this patient with valvular heart disease to increased peri-

operative risks. However, surgical drainage and débridement would be required if the he-matoma became infected and could not be ad-equately treated with percutaneous drainage.

Chronic expanding hematoma of the tho-rax is a clinical entity of uncertain cause that can present as a slowly growing chest wall mass [2, 3]. Surgical excision and drainage is usually required in these patients because of formation of granulation tissue and calci-fication. IV antibiotics would be indicated if there are clinical and radiologic features of infection but would not be effective alone in treating the hematoma.


A 53-year-old man presented with a his-tory of progressive dyspnea and altered sen-sation in the right upper limb. There was no significant medical history. A chest ra-diograph showed diffuse abnormality in the right hemithorax, and the patient subse-quently underwent CT of the thorax.

Description of the ImagesSelected axial images from a contrast-en-

hanced CT performed in the arterial phase show a large mass lesion in the right hemi-thorax, causing significant compressive atel-ectasis in the right lung. Although the largest component of the mass is intrathoracic, it ex-

tends through the superior sulcus to encase the right subclavian artery and the brachial plexus (Fig. 2A). The mass is predominantly of fat attenuation, with components of mildly enhancing soft-tissue attenuation at the an-teroinferior portion of the right hemithorax (Fig. 2B). Septations are identified within the fat component, especially inferiorly. Figure 2C is a coronal T2-weighted image showing the extent of abnormal high-signal tissue in-volving the right hemithorax and invasion of the hepatic dome through the right hemidia-phragm. Axial T1-weighted imaging shows high signal in the lipomatous components of the lesion (Fig. 2D). The soft-tissue compo-nents of the lesion in the right lower hemi-thorax exhibit low signal on unenhanced T1-weighted images (Fig. 2D) and high signal on T2-weighted images (Fig. 2E).

Differential DiagnosisThe differential diagnosis includes lipo-

sarcoma and atypical lipoma. The extension of the mass outside the right hemithorax, in-volvement of the superior sulcus, and inva-sion of the hepatic dome are consistent with an aggressive malignancy. The lesion extends along the right side of the mediastinum. Be-cause fat comprises the greatest component of the mass, it is difficult to determine the ex-tent of mediastinal invasion. Well-differenti-ated liposarcoma may contain large amounts

A CB

D

Fig. 2—53-year-old man with progressive dyspnea and altered sensation in right upper limb.A and B, Selected axial images from CT of thorax performed with IV contrast agent. C, Coronal T2-weighted image of thorax.D and E, Axial T1-weighted (D) and T2-weighted (E) images of lower thorax.

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of fatty tissue [4] and can therefore be difficult to distinguish from atypical lipoma in cases without overt signs of local invasion. Most li-pomas and liposarcomas do not contain areas of calcification. When calcification is present, it is not a reliable determinant of malignan-cy [4]. Large thickened septations in a lipo-matous lesion are suggestive of liposarcoma. However, thin septations such as those seen in this case are frequently seen in lipomas. Pri-mary liposarcoma in the mediastinum is rare, but reported findings include invasion of the pericardium and great vessels [5]. In this case, there is clear invasion through the diaphragm and into the dome of the liver. Nonadipose components are much more frequent in well-differentiated liposarcomas than in lipomas. However, up to 31% of lipomas may exhibit nonadipose components [4], so the presence of higher attenuation portions within the mass is not reliable in determining malignancy.

Diagnosis: LiposarcomaDistinguishing well-differentiated li-

posarcoma from lipoma can be a diagnos-tic challenge with radiologic imaging. Al-though lesions composed entirely of adipose tissue can be reliably identified as lipomas, the presence of nonadipose components does not definitively indicate malignancy. Imag-ing-guided biopsy targeting the nonadipose component of the lesion is an invasive proce-dure but is the best way to prove the diagno-sis. This is a less invasive option than surgi-cal biopsy. The extensive nature of the lesion in this patient means that accurate diagno-sis and staging are required before deciding whether surgical excision is appropriate. Al-though MRI is the best imaging technique to provide information on local staging, li-posarcoma cannot be reliably diagnosed by MRI features alone. Ultrasound may be helpful in distinguishing cystic lesions from myxoid elements of liposarcoma [6]. Howev-er, CT was performed with IV contrast agent in this case, and ultrasound is therefore un-likely to provide further information to aid in characterization of the lesion. PET/CT may be useful in the pretreatment assessment of liposarcoma [7]. However, FDG uptake by liposarcomas is variable [7, 8], and the ab-sence of significant FDG activity will not re-liably exclude malignancy. The liposarco-ma in this scenario exhibits a heterogeneous signal intensity pattern. There are large fo-cal areas in the right lower hemithorax with low signal on unenhanced T1-weight-ed MRI, high signal on T2-weighted MRI,

and amorphous enhancement on contrast-enhanced CT, suggesting a myxoid compo-nent. There are also larger areas of fat signal seen throughout the rest of the mass without significant contrast enhancement, consistent with well-differentiated fatty component. This appearance of variable signal intensity on MRI is commonly seen in larger liposar-comas, which can have multiple histologic subtypes within the same lesion [9]. Patients with well-differentiated liposarcoma have a much better prognosis after therapy than do patients with pleomorphic histologic subtype [6]. Myxoid liposarcoma has an intermediate prognosis [5, 6]. On histopathologic analy-sis, the tumor in this scenario had both well-differentiated and myxoid components. The patient subsequently developed metastatic disease a few years later, with histology indi-cating high-grade pleomorphic liposarcoma.


A 64-year-old woman with a history of left breast carcinoma was found to have an osseous abnormality in the left anterior chest

wall on a chest radiograph performed at rou-tine follow-up. The patient had sustained mi-nor injuries following a motor vehicle acci-dent 2 years previously and was otherwise asymptomatic.

Description of ImagesSelected axial (Fig. 3A) and sagittal (Fig.

3B) images of CT examination are displayed in bone window. An abnormal osseous ex-crescence is seen arising from the region of the left sternoclavicular joint, without evi-dence of osteolysis in the bones adjacent to the lesion. The lesion extends into the left chest wall, causing anterior displacement of the left pectoralis major muscle. Periosteal reaction is identified at the anterior aspect of the articular surfaces of both the manu-brium and the clavicle. The margins of the lesion are well defined, and no inflammato-ry changes are seen in the adjacent muscle or fat of the chest wall. On the sagittal view, bone proliferation can be seen on both sides of the sternoclavicular joint. Intraarticular gas is identified within the slightly widened left sternoclavicular joint. A reformatted cor-

A

Fig. 3—64-year-old woman with history of left breast carcinoma and osseous abnormality in left anterior chest wall on chest radiograph.A, Axial CT image of thorax in bone window.B, Sagittal CT image of thorax in bone window.C, Reformatted coronal image of sternoclavicular joints.D, Axial CT image of thorax obtained 3 years before images in A–C were obtained.

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Description of ImagesSelected axial images of MRI of the area

of clinical interest in the right posterior chest wall are displayed. A soft-tissue mass of in-termediate signal intensity on proton-den-sity imaging (Fig. 4A) and fat-suppressed T1-weighted (Fig. 4B) imaging is identified adjacent to the inferior tip of the right scapu-la. The lesion is more heterogeneous than the neighboring skeletal muscle on all sequenc-es, exhibiting alternating high and interme-diate signal areas. The mass exhibits avid enhancement on the contrast-enhanced se-quence (Fig. 4C).

Differential DiagnosisThe clinical features of progressive dis-

comfort in the chest wall over 3 months with-out significant history are not suggestive of an infective cause. The signal characteristics in-dicate an enhancing soft-tissue lesion, with-out areas of fluid signal to suggest an abscess. The lesion has ill-defined margins and shows prominent enhancement after contrast agent administration. Primary sarcoma of the chest wall is relatively uncommon. However, with the imaging characteristics and clinical pre-sentation, sarcoma should be considered in the differential diagnosis [14]. Neurofibromas typically have well-circumscribed margins and higher signal on T2-weighted imaging than seen in this lesion. Neurofibromas may also show a “target sign,” with central hypoin-tensity on T2-weighted imaging due to fibro-collagenous material [15], which is not pres-ent in this case. Plexiform neurofibromas can be infiltrative with variable signal pattern on

onal image (Fig. 3C) also shows the osseous abnormality involving both sides of the ster-noclavicular joint. Figure 3D shows an axial image from CT performed 3 years earlier at an outside hospital, with a stable appearance at the left sternoclavicular joint.

Differential DiagnosisA bony outgrowth is identified at the me-

dial end of the left clavicle and the adjacent portion of the sternal manubrium and ap-pears to be centered on the left sternoclavic-ular joint. This patient has no symptoms to suggest septic arthritis and no evidence of periarticular bone resorption or inflamma-tory changes in the adjacent soft tissues. Al-though chondrosarcoma can extend across joint spaces [10], the symmetric involve-ment of both articular surfaces and lack of osseous destruction is not suggestive of a primary bone neoplasm. Also, no chondroid matrix is visualized. The patient has a histo-ry of treated breast cancer, and the possibil-ity of an osseous metastasis has to be con-sidered. However, the joint-based nature of the lesion, lack of other osseous lesions, and stability over a 3-year period does not sug-gest metastatic disease. The imaging find-ings are consistent with hyperostosis of the sternoclavicular joint, with exuberant new bone formation centered around the joint and the presence of intraarticular gas. The “vacuum phenomenon” is seen as gas accu-mulation (mostly nitrogen) within synovial joints due to distraction of the articular sur-faces. This radiologic feature is also com-monly found within intervertebral disks as

a result of degenerative processes. The vac-uum phenomenon is rarely seen in infec-tions but occurs in osteoarthropathy, crystal deposition disease, and trauma [11]. Al-though the right sternoclavicular joint is not affected in this patient, published literature has described cases of bilateral hyperos-tosis associated with cutaneous symptoms [12, 13]. The SAPHO syndrome is a clini-cal entity consisting of synovitis, acne, pus-tulosis, hyperostosis, and osteitis. However, this patient does not have bilateral sterno-clavicular hyperostosis or palmar cutaneous lesions to suggest SAPHO syndrome.

Diagnosis: Sternoclavicular HyperostosisThe large amount of bone proliferation in

this case might initially raise the suspicion of a primary osseous neoplasm. However, the joint-centered nature of the lesion, the intact cortical margins, and lack of involvement of adjacent soft tissues point toward arthropa-thy. The presence of intraarticular gas is sug-gestive of osteoarthropathy, although it may also be seen with trauma and crystal deposi-tion disease [11]. The remote history of mi-nor chest trauma indicates a possible caus-ative factor for osteoarthropathy.


A 60-year-old man presented with increas-ing discomfort in the right posterior chest wall over a 3-month period. The patient had no sig-nificant medical history. On examination, there was an ill-defined palpable swelling ad-jacent to the inferior pole of the right scapula.

A

Fig. 4—60-year-old man with 3-month history of right posterior chest wall pain.A, Axial proton density–weighted image of thorax.B, Axial T1-weighted image of thorax with fat suppression.C, Axial T1-weighted image of thorax obtained after IV administration of gadolinium-based contrast agent.

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T1-weighted, T2-weighted, and contrast-en-hanced imaging. However, these lesions are almost exclusively seen in patients with neuro-fibromatosis type 1, in conjunction with mul-tiple cutaneous manifestations [16]. Elastofi-broma dorsi essentially always occurs in the subscapular area, is nonencapsulated, and has alternating fibrous and fatty tissue bands that produce a striated appearance on T1-weight-ed MRI in comparison with adjacent skeletal muscle [17]. Elastofibroma dorsi is a benign proliferation of fibrofatty tissue containing elastin fibers and therefore does not infiltrate adjacent osseous structures. Although elasto-fibromas usually exhibit only faint enhance-ment, more marked enhancement occasional-ly occurs in these lesions [18].

Diagnosis: Elastofibroma DorsiThe infrascapular location, striated ap-

pearance, and absence of invasion are strong-ly suggestive of elastofibroma [19]. However, the intense enhancement identified in this case is an atypical finding that necessitates further workup to exclude a soft-tissue tu-mor. Imaging-guided biopsy confirmed that this patient had an elastofibroma. Asymp-tomatic patients with more typical imaging characteristics may not require biopsy or ex-cision [17]. Elastofibroma dorsi is a benign soft-tissue pseudotumor characterized by ac-cumulation of collagenized tissue with elas-tic fibers. These lesions are most common in elderly women and are an important differ-ential diagnosis to consider when an infra-scapular soft-tissue lesion is present. Elas-tofibroma dorsi often presents as bilateral subscapular masses [17, 18]. The presence of

bilateral lesions with typical imaging char-acteristics is essentially diagnostic, obviat-ing tissue diagnosis. Imaging-guided biopsy is the least invasive option when pathologic diagnosis is required. A core biopsy should distinguish between malignant lesions and elastofibroma, which will exhibit elastic fi-bers in collagenized fibrofatty tissue [18]. If the results of percutaneous biopsy are equiv-ocal or the lesion is causing significant func-tional impairment, surgical biopsy or exci-sion will be required [18].


A 50-year-old man presented with right posterior rib pain. The patient had no signifi-cant medical history and there was no history of trauma. Selected images of CT and MRI examinations of the thorax are displayed.

Description of ImagesThe axial CT image (Fig. 5A) shows a

large soft-tissue lesion in the posterior right chest wall, causing osseous destruction of the adjacent rib. Figure 5B is an axial T2-weighted MRI scan revealing invasion of the right lamina and right pedicle of the T5 vertebra. The mass extends into and widens the right neural foramen (Fig. 5C), abutting the right side of the spinal canal. The lesion is homogeneous in attenuation on CT (Fig. 5A). It is of intermediate-to-high signal on T2-weighted MRI (Figs. 5B and 5C), with no evidence of central heterogeneity or fluid sig-nal to suggest necrosis. The lesion forms an obtuse angle with the chest wall and has both chest wall and intrathoracic components.

Differential DiagnosisThe obtuse angle between the chest wall

and the mass suggests an extrapulmonary lo-cation. Although the lesion may arise from the pleura, mesothelioma usually progresses in a circumferential pattern around the hemi-thorax, rather than the focal expansile manner seen in this case. No pleural plaques are seen to indicate prior asbestos exposure, which is the primary risk factor for mesothelioma. Al-though chondrosarcoma is the most common primary malignancy of the chest wall, it usu-ally occurs more anteriorly than the lesion in this scenario. Chondrosarcoma is often cen-tered on the sternum or costochondral carti-lage [14]. Stippled areas of calcification due to chondroid matrix are often seen in chon-drosarcoma, but no calcification is observed in this scenario. The most likely causes of an expansile soft-tissue mass with rib osteolysis in a patient of this age group are plasmacy-toma or multiple myeloma or osseous metas-tases. Myeloma is the most common prima-ry bone marrow malignancy in adults [20]. Most plasmacytomas arising from bone are osteolytic in nature and usually do not con-tain intralesional calcifications [21]. In this case, there is widening of the right neural foramen caused by infiltration of the lesion. Neuroforaminal widening is typical of pe-ripheral nerve sheath tumors such as neuro-fibroma and schwannoma. However, other neoplasms, including plasmacytoma and in-fectious diseases, can cause this finding [22].

Diagnosis: PlasmacytomaMost patients with solitary myeloma (plas-

macytoma) are male and older than 50 years

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Fig. 5—50-year-old man with right posterior rib pain.A, Axial CT image of thorax.B and C, Axial T2-weighted MRI scans of thorax.

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Fig. 6—48-year-old man with incidental finding of upper right chest wall lesion on CT.A, Contrast-enhanced axial CT image of upper right hemithorax in bone window.B, Contrast-enhanced axial CT image of upper right hemithorax in soft-tissue window.C, Contrast-enhanced coronal CT image of thorax.D, Coronal FDG PET image.

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component, the absence of any areas of fat attenuation within the lesion is not consistent with lipoma.

Diagnosis: SchwannomaSchwannomas are peripheral nerve sheath

tumors that most often present in adults as asymptomatic slow-growing lesions [22]. They typically have a well-defined encapsu-lated appearance and commonly cause ero-sion of adjacent bony structures as a result of a pressure effect. Benign peripheral nerve

erosion of adjacent cortical bone and dumb-bell shape of the mass are recognized fea-tures of a benign peripheral nerve sheath tu-mors, such as schwannoma or neurofibroma. It is often difficult to differentiate schwan-noma from neurofibroma on radiologic im-aging. An eccentric location relative to the parent nerve and areas of cystic degeneration are more suggestive of schwannoma [22, 26]. However, these imaging features are not present in the current scenario. Although atypical lipomas may have a large soft-tissue

[23]. Although these lesions are relative-ly common, the imaging features are non-specific. Plasmacytomas usually arise from bone and are often expansile in nature [24]. The most frequent sites include the vertebral column and ribs [23, 24]. Solitary myeloma may also originate in extraosseous soft tis-sues [25]. Biopsy of this lesion confirmed a plasmacytoma. No other sites of bone dis-ease were identified on skeletal survey. The extraosseous soft-tissue component may pre-dominate, as in this case. Expansile osteolyt-ic metastases, such as those resulting from primary renal or thyroid malignancy, could cause a similar appearance. Radiologic im-aging plays an important role in determin-ing the disease burden in patients with my-elomatous disease, including complications such as pathologic factors [25]. Eighty-five percent of patients with solitary plasmacy-toma will develop multiple myeloma within several years of initial diagnosis [23].


A 48-year-old man underwent CT examina-tion of the thorax, which revealed an incidental finding of an upper right chest wall mass. The patient had no symptoms related to the mass.

Description of ImagesContrast-enhanced CT shows a homoge-

neous well-circumscribed right subclavicu-lar soft-tissue mass, which is slightly hypoat-tenuating in comparison with the adjacent skeletal muscle (Figs. 6A–6C). The lesion extends into the first intercostal space and has a dumbbell shape (Fig. 6B). There is mild scalloping and erosion of the right later-al second rib adjacent to the mass lesion (Fig. 6A). The mass is mildly FDG avid on PET/CT examination (Fig. 6D). No other FDG-positive disease is seen in the chest.

Differential DiagnosisThe dumbbell shape of the mass and exten-

sion into the intercostal space is unusual for a lymph node. There is no evidence of central ne-crosis on PET, which would be expected with a lymph node lesion of this size. The asymptom-atic nature of the lesion does not suggest an in-fective cause. Also, there is no central low at-tenuation within the lesion to indicate fluid, and no inflammatory change is seen in the adjacent fat of the right chest wall to an abscess. The well-defined margins, homogeneous appear-ance, and asymptomatic nature of the lesion are suggestive of a slow-growing entity. The

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sheath tumors often exhibit prominent en-hancement on contrast-enhanced images [15, 26] and may be mildly FDG avid on PET, as in this case [27]. Although these lesions are generally benign, malignant transformation can occur. Imaging features suggestive of a malignant peripheral nerve sheath tumor in-clude indistinct margins and myxoid stroma, but these findings are nonspecific [28].


A 39-year-old woman presented with per-sistent left anterior chest wall pain over a 3-month period. There was no significant medical history.

Description of ImagesThe posteroanterior chest radiograph (Fig.

7A) shows opacity centered on the anterior aspect of the left fifth rib. The axial CT im-age in bone window shows that the lesion is expansile, with fine bony spicules radiating from the central portion and loss of the nor-mal cortical rib margins (Fig. 7B). The mass exhibits high signal on T2-weighted imaging with fat suppression with lower signal in the central portion of the lesion (Fig. 7C). There is prominent peripheral enhancement on the axial contrast-enhanced MRI (Fig. 7D) and peripheral uptake of FDG on the axial PET image (Fig. 7E). Figure 7F shows the gross pathologic appearance of the lesion after sur-gical resection, with central fibrous stroma-

containing areas of calcification and a highly vascular peripheral component.

Differential DiagnosisThe lesion has indeterminate radiologic

features. The expansile nature and prominent enhancement suggest an aggressive process. No other lesions are identified in the visual-ized bony skeleton on the chest radiograph or PET/CT examination. Although metastases are the most common neoplastic rib lesion, primary malignant lesions (e.g., chondrosar-coma) or benign lesions (e.g., fibrous dyspla-sia) must be considered in the differential di-agnosis of a solitary expansile rib lesion [29]. Further investigation should be performed to secure a diagnosis unless there are clini-cal contraindications to further workup. As in this scenario, expansile rib lesions may lack definitive radiologic features, necessitating tissue diagnosis [30]. Excisional biopsy could be considered as the next step for this patient, but securing the diagnosis with imaging-guid-ed biopsy would probably be preferable so that the surgical approach can be optimized.

Diagnosis: Rib HemangiomaThe expansile nature of the mass with ra-

diating bony spicules made definitive diagno-sis on the basis of radiologic imaging alone difficult. Preoperatively, a primary malignant tumor of the rib, such as low-grade chondro-sarcoma or, less likely, osteosarcoma, was suspected. PET/CT did not reveal any other

lesions. Primary intraosseous hemangioma most frequently occurs in the vertebrae and skull. However, there are published case re-ports describing rib hemangiomas with radio-logic features similar to those in this scenario [31, 32]. Patients with rib hemangioma usu-ally present with a solitary expansile rib le-sion, which may cause pain or a palpable chest wall mass [33]. These lesions usually enhance on contrast-enhanced CT or MRI. Some hem-angiomas have a spiculated or sunburst ap-pearance due to fine linear calcifications, as seen in this patient. This scenario highlights the limitations of imaging alone and the im-portance of definite histologic diagnosis in the management of chest wall tumors. Chest wall tumors may be sampled using fine-needle as-piration biopsy, excisional biopsy, and inci-sional biopsy. In general, fine-needle aspira-tion biopsy is not recommended unless there is a strong suspicion of myeloma or metastatic disease. Excisional biopsy is performed for le-sions less than 2–3 cm in diameter, and larger lesions usually undergo incisional biopsy. In this case, the PET/CT scan showing promi-nent FDG activity in the periphery of the le-sion would have provided useful information to direct needle biopsy or incisional biopsy. However, because the preoperative working differential diagnosis was low-grade primary malignant tumor of the chest wall, no preop-erative biopsy was done. Therefore, resection was performed for both definitive diagnosis and treatment.

A

Fig. 7—39-year-old woman with 3-month history of persistent left anterior chest wall pain.A, Posteroanterior chest radiograph.B, Axial CT image of thorax in bone window.C, Axial T2-weighted image of thorax with fat suppression.

(Fig. 7 continues on next page)

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A 31-year-old man presented with a 1-month history of persistent left upper chest wall pain. He had no significant medical his-tory and no systemic clinical features.

Description of ImagesAxial CT shows a soft-tissue mass with

osseous destruction involving the left ster-nal manubrium (Fig. 8A). The lesion has a large soft-tissue component that extends into the extraosseous tissues (Fig. 8B). The le-sion extends into the anterior mediastinal fat but appears to maintain a narrow plane of separation from the aortic arch. There are amorphous areas of irregular and arclike calcification within the mass. Axial contrast-enhanced MRI (Fig. 8C) shows peripher-al enhancement of the lesion and delineates its extension into adjacent soft-tissue struc-tures. The central portion of the mass is het-erogeneous, with relative hypoenhancement. A coronal STIR image (Fig. 8D) shows high signal throughout the lesion on T2-weighted imaging with fat suppression.

Differential DiagnosisThe lesion is centered on the left side of the

manubrium, with associated osseous destruc-tion. The mass also extends into the adjacent

soft tissues of the left chest wall, indicating an aggressive lesion. The patient’s age and absence of any prior clinical history of ma-lignancy makes a bone metastasis less likely. The mass has an enhancing soft-tissue com-ponent with cortical breakthrough. In the ab-sence of fat stranding, these findings are more suggestive of a primary bone tumor rather than osteomyelitis. Although osteomyelitis has aggressive radiologic features, bony de-struction and fat stranding are usually the pre-dominant features, and a soft-tissue phlegmon is generally minimal. Also the areas of amor-phous calcification and lack of systemic clini-cal features do not favor an infective process. The finding of a chest wall lesion with aggres-sive features including bone destruction and amorphous calcification in a young adult is most consistent with a primary osseous neo-plasm. Chondrosarcoma is the most common primary malignant tumor of the chest wall [24]. It is usually osseous in origin [34] and most frequently occurs in the costochondral region or sternum, as in this case [24]. How-ever, osteosarcoma may contain areas of min-eralization and must also be considered in the differential diagnosis.

Diagnosis: ChondrosarcomaThe clinical and radiologic features in this

case are consistent with a primary malignant

neoplasm arising from the sternum. Differ-entiating between chondrosarcoma and os-teosarcoma according to imaging features alone may be difficult. Both tumors typically exhibit enhancement on contrast-enhanced imaging and cause osseous destruction [24, 35]. Chondrosarcomas typically have stip-pled and arclike calcifications, whereas os-teosarcomas tend to have dense foci of calci-fication located predominantly in the central portion of the tumor [24]. Osteosarcoma is less common than chondrosarcoma of the chest wall and typically has a rib, scapular, or clavicular location [14]. Biopsy of the le-sion in this patient confirmed that it was a chondrosarcoma. Radiation-induced chon-drosarcoma and osteosarcoma of the chest wall have been reported in some patients who undergo radiation therapy for Hodgkin disease and breast cancer [36]. However, as in this case scenario, most patients with pri-mary chondrosarcoma of the chest wall have no history of prior irradiation.

ConclusionThe clinical case scenarios presented here

illustrate the utility of radiologic imaging in the management of chest wall masses. A sys-tematic problem-based approach is required to define the differential diagnosis and to de-termine the most appropriate investigation to

D

Fig. 7 (continued)—39-year-old woman with 3-month history of persistent left anterior chest wall pain.D, Axial contrast-enhanced T1-weighted image of thorax with fat suppression.E, Axial FDG PET image.F, Gross pathologic specimen of rib lesion after surgical excision.

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characterize the lesion. In situations where it is not possible to secure a diagnosis by imag-ing features alone, chest wall masses are of-ten amenable to percutaneous biopsy under CT or ultrasound guidance. PET/CT may be helpful in targeting biopsy toward metaboli-cally active areas, which are likely to have a greater diagnostic yield. The correlation of clinical, radiologic, and pathologic data is required for optimal treatment planning of chest wall masses.

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Fig. 8—31-year-old man with left upper chest wall pain for 1 month.A, Axial CT image of thorax in bone window.B, Axial CT image of thorax in soft-tissue window.C, Axial contrast-enhanced T1-weighted image of thorax with fat suppression.D, Coronal STIR image.

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F O R Y O U R I N F O R M A T I O N

This article is available for CME credit. See www.arrs.org for more information.

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chest wall mass

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