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The Breast Imager’s Approach to Nonmammary Masses at Breast and Axillary US: Imaging Technique, Clues to Origin, and Management1 Matthew C. Oliff, MD Robyn L. Birdwell, MD Sughra Raza, MD Catherine S. Giess, MD RadioGraphics 2016; 36:7–18 Published online 10.1148/rg.2016150029 Content Codes: From the Department of Radiology, Breast Imaging Section, Brigham and Women’s Hospital and Harvard University, Boston, Mass. Presented as an education exhibit at the 2014 RSNA Annual Meeting. Received February 19, 2015; revision requested June 5 and received June 25; accepted July 23. For this journal-based SA-CME activity, the authors, editor, and reviewers have disclosed no relevant relationships. Address correspondence to M.C.O., Department of Radiology, Portsmouth Regional Hospital, 333 Borthwick Ave, Portsmouth, NH 03801 (e-mail:
[email protected]). 1
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SA-CME LEARNING OBJECTIVES After completing this journal-based SA-CME activity, participants will be able to: ■■Discuss the differential diagnosis of nonmammary non–lymph node lesions in the axilla and chest wall. ■■Use
imaging clues and knowledge of the chest wall and axillary anatomy to identify when a lesion in these regions may be of nonmammary non–lymph node origin. ■■Recognize
how identification of a nonmammary non–lymph node lesion in the chest wall or axilla will dictate patient care. See www.rsna.org/education/search/RG.
Ultrasonography (US) of the breast and axilla is primarily used to evaluate a symptomatic patient or to further investigate findings identified with other imaging modalities. Breast imagers are generally familiar with US evaluation of level I, II, and III axillary lymph nodes in the diagnosis and staging of breast cancer. However, the axilla contains nonlymphatic tissue as well, including muscle, fat, and vascular and neurologic structures, and anatomically the breast lies on the chest wall. Therefore, lesions of nonmammary and non–lymph node origin in the axilla or chest wall are not infrequently encountered during US evaluation of the breast or axilla. In fact, such lesions may be the reason that the patient presents to the breast imaging department for evaluation. Understanding the anatomy of the chest wall and axilla and using a systematic US approach will help radiologists expedite accurate diagnosis, suggest optimal additional imaging, and streamline appropriate clinical referral. Key imaging features of nonmammary non–lymph node masses are highlighted, and case examples are provided to illustrate these features. Appropriate patient management is critical in these cases because referral to a breast surgeon may not be the best next step. Depending on institutional referral patterns, other subspecialty surgeons will be involved. Online supplemental material is available for this article. ©
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Introduction
At our breast imaging practice, ultrasonography (US) is primarily used to further evaluate findings identified with other imaging modalities (eg, magnetic resonance [MR] imaging or mammography) or to evaluate a clinical concern such as a palpable mass or focal pain. Breast imagers are generally familiar with US evaluation of level I, II, and III axillary lymph nodes in diagnosis and staging of breast cancer (1), and, while the majority of US findings will be of mammary or lymph node origin, lesions of nonmammary non–lymph node origin are occasionally encountered (2–5). The differential diagnosis for such lesions is broad and includes tumors of mesenchymal or nerve sheath origin, vascular lesions, posttraumatic injuries, and conditions related to infection or inflammation (2–5). Furthermore, with the increasing prevalence of breast density legislation, US is increasingly being performed for screening, which increases the likelihood that such lesions will be encountered. Although not every such lesion can be easily categorized as nonmammary or non–lymph node in origin, understanding the anatomy of the chest wall and axilla and using a systematic approach to US will
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TEACHING POINTS ■■
A lesion arising deep to the superficial fascia of the chest wall musculature is unlikely to be of mammary origin.
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When breast US findings in a symptomatic patient are negative, evaluating the tissues deep to the breast may be helpful to assess for lesions of chest wall origin.
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In some patients, particularly thin patients, flexing the shoulder (moving the elbow toward the ceiling) during US can facilitate probe-skin contact.
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If an anechoic lesion is encountered in the axilla, Doppler imaging is crucial to evaluate for a vascular lesion or an extremely hypoechoic lymph node or mass.
■■
If sarcoma is part of the differential diagnosis for a lesion, a discussion with the surgeon regarding the biopsy approach is paramount because biopsy tracts are resected at our institution at the time of sarcoma resection. Performing a biopsy through a particular muscle or anatomic compartment may necessitate its resection and increase patient morbidity.
help the breast imager distinguish these lesions from the more typical breast lesions encountered. An anatomic and systematic US approach will facilitate lesion evaluation as well as patient management because referral to a breast surgeon or performance of a percutaneous biopsy may be inappropriate. In this article, we review the anatomy of the chest wall and axilla from the perspective of a breast imager performing US and propose a systematic approach to US of the chest wall and axilla. We then describe key imaging features of nonmammary non–lymph node lesions, review the differential diagnosis for such lesions, discuss appropriate patient management, and provide illustrative case examples.
Anatomy of the Chest Wall and Axilla Chest Wall The anterior chest wall is composed of skin, subcutaneous tissues (including fat, breast tissue, and dermal appendages such as hair follicles and sebaceous glands), muscles, and ribs (Fig 1) (4). The pectoralis major and minor muscles underlie the majority of the breast, except inferolaterally, where the serratus anterior muscle is seen (Fig 1) (6). The ribs and intervening intercostal muscles form the deepest portion of the anterior chest wall and sit just superficial to the pleura and lung and beneath the aforementioned muscles (6).
Axilla The axilla is an anatomic space that serves as a conduit for nerves, lymphatics, and vessels to communicate between the upper extremity and the neck and/or thorax. According to Moore et
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al (6), the axilla can be visualized structurally as a four-sided pyramid. It has an apex, a base, and four walls. The apex of the axilla is blunted and points superomedially toward the head. The lateral wall is narrow, and the base and remaining walls are broad. The apex is bounded by the first rib, clavicle, and superior scapular border and contains the major neurovascular structures. These include the axillary artery and vein as well as portions of the brachial plexus and its branches (6). Discussion of the detailed anatomy of the neurovascular structures is beyond the scope of this article but has been provided by other authors (7,8). The medial wall is the chest wall, and the lateral wall is the proximal humerus. The anterior wall is made up of the pectoralis muscles, and the posterior wall is composed of the scapula and subjacent muscles (latissimus dorsi and teres major). Inferiorly, the anterior and posterior walls form the anterior and posterior axillary folds, respectively, which are useful surface landmarks during imaging. The base is made up of the skin over which most of the US examination takes place. When US of the axilla is performed (Fig 2), it is helpful to use this pyramid concept to ensure a systematic and complete examination.
US Technique for Chest Wall and Axilla General Considerations In our practice, breast and axillary US are usually performed for specific symptoms (eg, a palpable concern or focal pain) or to further evaluate a finding identified at mammography or other imaging. At our institution, these studies are performed by the breast imager by using a highfrequency linear-array transducer (12 MHz or 17 MHz). Although compound imaging is routinely used, ancillary US techniques such as Doppler and harmonic imaging can also be helpful for lesion evaluation and image optimization.
Chest Wall The breast, underlying muscles (pectoralis major and minor and/or serratus anterior), ribs, intercostal muscles, pleura, and lung are well seen at US (Fig 3). In general, the chest wall deep to the breast is evaluated incidentally as part of a breast US examination. While imaging the breast, it is important to ensure that the superficial fascial surface of the underlying musculature of the chest wall is seen. This ensures that the entire depth of the breast tissue has been evaluated and allows the imager to localize a lesion as intramammary or extramammary. A lesion arising deep to the superficial fascia of the chest wall musculature is unlikely
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Oliff et al 9 Figure 1. Normal chest wall anatomy at computed tomography (CT). (a) Axial image through the superior thorax shows the pectoralis major (black arrow), pectoralis minor (white arrow), and intercostal (arrowhead) muscles. The pectoralis minor muscle is deep to the pectoralis major muscle. (b) More inferior axial image shows the serratus anterior (black arrow) and intercostal (white arrow) muscles. (c) Coronal image shows the multiple slips of the serratus anterior muscle (black arrows) and the pectoralis major (white arrow) and pectoralis minor (arrowhead) muscles.
Figure 3. Long-axis gray-scale US image shows normal chest wall anatomy: the rib (white arrow), pectoralis major muscle (black arrow) and its superficial fascia (curved black line), intercostal muscles (black arrowhead), underlying lung (J) and pleura (white arrowhead), and overlying breast tissue (*).
Axilla Figure 2. Photograph illustrates the pyramid concept of the axillary space at US. The anterior wall (superimposed on the posterior wall, medial wall, and base) is not labeled, and the apex is marked (*). The position shown is not typical patient positioning for US because the patient’s arm is down by the side, but this position was used to help conceptualize axillary anatomy.
to be of mammary origin (4). Furthermore, in our experience, when breast US findings in a symptomatic patient are negative, evaluating the tissues deep to the breast may be helpful to assess for lesions of chest wall origin (Fig 4).
Proper patient positioning is important to facilitate proper imaging. We suggest placing the patient in an anterior oblique position and positioning a wedge pillow for support under the ipsilateral shoulder, with the patient’s arm placed over the head. This allows the base of the pyramid, along which the US probe will slide, to be parallel to the floor. The anterior and posterior axillary folds are then identified (Fig 5) and are used as landmarks during imaging to demarcate the anterior and posterior walls of the axilla. In some patients, particularly thin patients, flexing the shoulder (moving the elbow toward the ceiling) during US can facilitate probe-skin contact.
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Figure 4. Imaging of a 63-year-old woman with left breast pain. No abnormality was seen in the breast parenchyma at US. (a) Gray-scale US image obtained along the short axis of the rib underlying the site of pain shows cortical disruption (arrow) consistent with a rib fracture. (b) Coned-down chest radiograph confirms a minimally displaced acute fracture of the left tenth rib (arrow).
Figure 5. Photograph shows suggested patient positioning for axillary US. Note the use of a wedge pillow (J) for anterior oblique positioning. The anterior (white arrow) and posterior (black arrow) axillary folds serve as useful landmarks at US.
The following steps are suggested as a systematic approach to imaging the axilla and ensuring that the entire axilla is evaluated (the suggested technique is demonstrated in the Movie): 1. Identify the inferior aspect of the anterior axillary fold and use this as the starting point for transverse image acquisition. The lateral edge of the pectoralis major muscle will make up the medial side of the image, and the axillary contents will be lateral (Fig 6). 2. Advance the probe along the edge of the pectoralis major muscle until the humeral head is seen. 3. Shift the probe toward the posterior axillary fold and again sweep from inferior to superior to reach the humeral head. Repeat this process until the entire axilla is imaged (generally two or three passes is sufficient). The final pass should be along the posterior axillary fold, with the lateral edge of the latissimus dorsi or teres major muscle making up the lateral margin of the image (Fig 7). 4. A similar approach is taken with longitudinal images. Sweep the probe from the anterior axillary fold to the posterior axillary fold, and move the probe superiorly until the entire axilla is imaged (Fig 8). 5. Finally, identify the axillary neurovascular structures, specifically the axillary vein and artery, which will be visible at the apex of the axilla as they pass by the humeral head (Fig 9). The axillary vein can be distinguished from the
axillary artery by its more superficial location and its compressibility with manual pressure; furthermore, Doppler imaging will demonstrate blood flowing toward (vein) or away from (artery) the thorax. Branches of the brachial plexus run adjacent to the axillary vessels; a detailed discussion of these structures is beyond the scope of this article but is provided elsewhere (7,8). A mass close to these structures may be of vascular or nerve sheath origin, and, in the case of interventional procedure planning, identification of these structures is necessary to avoid neurovascular injury. In the absence of axillary breast tissue, cysts should not occur in the axilla. If an anechoic lesion is encountered in the axilla, Doppler imaging is crucial to evaluate for a vascular lesion or an extremely hypoechoic lymph node or mass. An exception to this rule of thumb is epidermal inclusion cysts, which may appear anechoic (9); however, their origin in the dermis and the identification of a tract to the skin surface should help differentiate them from deeper lesions that may be vascular in origin.
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Figure 6. Photograph (a) and gray-scale US image (b) show the suggested starting position for short-axis axillary US, at the inferomedial aspect of the axilla. In b, the pectoralis major muscle (outlined in black) makes up the medial edge of the image, and the axillary contents (arrow) are lateral. Depending on the transducer angulation, the axillary artery (A) and vein (V) may be visible.
Figure 7. Photograph (a) and gray-scale US image (b) show the suggested final position for short-axis axillary US, at the superolateral aspect of the axilla. In b, the teres major muscle or the latissimus dorsi muscle (outlined in black) makes up the lateral edge of the image, and the humeral head (J) is in view.
Figure 8. Photograph (a) and gray-scale US image (b) show the suggested starting position for long-axis axillary US. Note that the probe lies against the anterior axillary fold in a. In b, the pectoralis major muscle (black arrow) and underlying rib (arrowhead) and intercostal muscles (white arrow) are seen.
Differential Diagnosis
The differential diagnosis for nonmammary non–lymph node lesions in the chest wall can be broadly thought of as neoplastic (benign or malignant); vascular; inflammatory; infectious; and posttraumatic, postbiopsy, or postsurgical le-
sions. Although there is overlap in the differential diagnosis for axilla and chest wall lesions, certain types of lesions have a propensity for one site more than the other (Tables 1, 2). In the axilla, vascular lesions and nerve sheath tumors should be considered. The axillary artery
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Figure 9. Gray-scale US image shows the axillary artery (arrow) and vein (arrowhead) as they travel over the humeral head (J). The accompanying nerves are not well seen but travel adjacent to the axillary vessels. Identification of these structures during procedural planning may help avoid neurovascular injury.
Table 1: Differential Diagnosis of Nonmammary Lesions in the Chest Wall at Breast US
Table 2: Differential Diagnosis of Non–Lymph Node Lesions at Axillary US
Fatty origin Lipoma Liposarcoma Dermal origin Sebaceous cyst Epidermal inclusion cyst Bone, cartilage, or muscle or other soft-tissue origin Bone and soft-tissue sarcomas Nodular fasciitis Desmoid fibromatosis Metastasis Posttraumatic or postsurgical origin Fracture Scar tissue Seroma Hematoma Infectious or inflammatory origin Myositis Abscess
Fatty origin Lipoma Liposarcoma Neurogenic origin Schwannoma Neurofibroma Malignant peripheral nerve sheath tumor Vascular origin Aneurysm Pseudoaneurysm Arteriovenous fistula Thrombosis Hemangioma Lymphatic origin Lymphangioma Dermal origin Sebaceous cyst Epidermal inclusion cyst Bone, cartilage, or muscle or other soft-tissue origin Soft-tissue sarcomas Nodular fasciitis Desmoid fibromatosis Metastasis Posttraumatic or postsurgical origin Scar tissue Seroma Hematoma Infectious or inflammatory origin Myositis Abscess
Source.—References 2–5, 10–13.
and vein are superficial in location, and abnormalities related to them or to their branches may be encountered. These include aneurysms (Fig 10), pseudoaneurysms, vascular malformations, and arteriovenous fistulas. These lesions will be partially or completely anechoic, and this feature should prompt the breast imager to perform Doppler imaging. In addition, eliciting a history of any pertinent prior interventional procedure (eg, central line placement) or surgical procedure in the region is important (Fig 11). Nerve sheath tumors such as schwannomas, neurofibromas, and malignant peripheral nerve sheath tumors should be considered when a solid lesion is found close to the axillary artery and vein (2,10,14,15). Although schwannomas and neurofibromas are benign entities, generally only schwannomas can be resected without sacrificing the involved nerve. Malignant peripheral nerve sheath tumors often
Source.—References 2–5, 10–13.
arise from neurofibromas, half of which occur in patients with neurofibromatosis type 1 (14). Although they cannot reliably be distinguished from one another sonographically (15), these neurogenic tumors should be considered for any solid mass with an intimate relationship to the axillary artery and vein (and, hence, to the abutting branches of the brachial plexus).
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Figure 10. Imaging of a 68-year-old woman with previous left mastectomy for breast cancer who was referred for breast imaging for a palpable left supraclavicular abnormality concerning for lymphadenopathy. (a) Transverse grayscale targeted US image shows an anechoic tubular structure traveling under the clavicle (white arrow) with a focal outpouching (black arrow). (b) Color Doppler US image shows pulsatile flow traveling toward the left upper extremity. Physical examination confirmed that the palpable concern was pulsatile, and the finding was diagnosed as a left subclavian artery aneurysm. Further history revealed that the patient had a history of multiple aneurysms but no formal diagnosis of a connective tissue disease. (c) Coronal chest CT angiographic image that was obtained previously and retrospectively reviewed shows focal dilatation (black arrow) of the left subclavian artery. The normal portion of the artery (arrowhead) and the clavicle (white arrow) are also noted. The patient was referred to her vascular surgeon.
Figure 11. Imaging of a woman who was referred with a palpable mass in the left axilla. (a) Short-axis gray-scale US image shows an anechoic mass (arrow) lying just lateral to the pectoralis muscle (J) and superficial to the humeral head (arrowhead). (b) Color Doppler US image shows a “to and fro” flow pattern. History obtained from the patient at imaging revealed that she had a remote history of ipsilateral central venous catheter placement. The finding was diagnosed as a pseudoaneurysm of the axillary artery. In this case, referral to a vascular surgeon would be appropriate.
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Figure 12. Imaging of a 43-year-old woman with a palpable nodularity in the inner right breast and negative mammographic findings. (a) Long-axis gray-scale US image shows a heterogeneous mass (white arrow) deep to the pectoralis fascia (black arrow). The mass was seen to lie within a rib, the cortex of which is well seen (arrowhead). Chest CT was recommended because of the osseous origin of the mass. (b) Axial nonenhanced chest CT image shows an expansile lesion with internal mineralization (arrow) within an anterolateral rib. Biopsy demonstrated chondrosarcoma. The patient was referred to an orthopedic surgeon specializing in oncology.
Figure 13. Imaging of a 62-year-old woman with a palpable finding in the right breast and negative mammographic findings. (a) Long-axis gray-scale US image shows a hypoechoic mass (black arrow) with a broad base along the chest wall. The white arrow indicates the pleural surface. (b) Image along the cranial aspect of the mass shows the mass (white arrow) arising from the pectoralis major muscle (arrowhead), a finding concerning for chest wall origin. The pleura (black arrow) is well seen. Biopsy revealed spindle cell sarcoma, and breast MR imaging was recommended. (c) Sagittal contrast-enhanced MR image shows a centrally necrotic mass (arrow) with a broad base of attachment on the chest wall. The patient was referred to an oncologist specializing in soft-tissue sarcomas.
In the chest wall, lesions of muscular and osseous origin may occur. These include soft-tissue and bone sarcomas (Figs 12, 13); benign neoplasms (Fig 14); and posttraumatic (eg, fracture, muscle injury), postsurgical (Fig 15), infectious, and inflammatory conditions (4,5,10–13). Lesions that may occur in either the axilla or chest wall include lipomas (Figs 16, 17), nodular fasciitis (Fig 18), and desmoid fibromatosis (Fig 19) (10,16). Nodular fasciitis is a benign
self-limited proliferation of fibroblasts that can manifest as a rapidly growing, palpable, sometimes painful mass that does not recur after resection (10,14,16). Desmoid fibromatosis, on
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Figure 14. Imaging of a 61-year-old woman who was referred with a palpable finding in the right axilla. (a) Short-axis gray-scale US image shows a vague region of altered echotexture (white outline) in the latissimus dorsi muscle. Note the normal-appearing striated muscle fibers deep to this region (arrow). Because of the lesion’s intramuscular location, contrast-enhanced MR imaging was recommended. (b) Axial contrast-enhanced MR image shows a region of ill-defined enhancement in the latissimus dorsi muscle (arrow) that corresponds to the US finding. The patient was referred to an orthopedic surgeon specializing in oncology. A subsequent core-needle biopsy was nondiagnostic. Pathologic analysis after surgical resection revealed a benign intramuscular angioma.
Figure 15. Imaging of a woman who was referred with an enlarging right breast after lung transplant. (a) Short-axis gray-scale US image of the right breast shows a large anechoic collection (black arrow) deep to the pectoralis muscle (white arrow). Given the lack of clinical concern for infection, a seroma was diagnosed. (b) Subsequent axial chest CT image obtained for a different indication redemonstrates the subpectoral seroma (arrow). The patient was treated conservatively.
the other hand, is a locally aggressive proliferation of fibroblasts that grows in an infiltrative manner and can locally recur (10,14). Most of the aforementioned entities do not have a specific US appearance. Infectious, inflammatory, and posttraumatic, postbiopsy, or postsurgical findings will often have a fluid or cystic component, and scar tissue is generally not masslike. Vascular lesions will be anechoic or hypoechoic with prominent Doppler flow, and pseudoaneurysms have a characteristic “to and fro” or yin-yang appearance at color Doppler US. However, soft-tissue masses will have a nonspecific sonographic appearance and often require further evaluation with MR imaging.
Patient Management
When a nonmammary non–lymph node lesion is suspected, appropriate referral for additional imaging and/or referral to the appropriate surgeon is essential. Familiarity with institutional referral patterns is important. At our institution, soft-tissue masses of unknown origin are usually managed by orthopedic surgeons with subspecialty training in oncology. If sarcoma is part of the differential diagnosis for a lesion, a discussion with the surgeon regarding the biopsy approach is paramount because biopsy tracts are resected at our institution at the time of sarcoma resection. Performing a biopsy through a particular muscle or anatomic compartment may necessitate its resection and
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Figures 16, 17. (16) Imaging of a 31-year-old woman who was re-referred for breast imaging of a persistent palpable right axillary mass after negative axillary US findings several months earlier. Mammographic findings were negative. (a) Long-axis gray-scale US image shows a heterogeneous mass (arrow) underlying the biceps muscle (arrowhead). The breast imager recommended shoulder MR imaging. (b, c) Sagittal T1-weighted (b) and fat-suppressed T1-weighted (c) MR images show a circumscribed oval mass (white arrow) deep to the short head of the biceps muscle (black arrow), with signal loss seen after fat saturation, a finding consistent with a lipoma. Because the imaging results were diagnostic, no further management was needed. (17) Imaging of a 44-year-old man who was referred with a palpable left breast finding. (a) Mediolateral oblique mammogram shows a partially imaged fat-attenuating lesion (white arrow) in the pectoralis major muscle (black arrow). (b) Short-axis gray-scale US image shows an isoechoic mass (arrow) in the pectoralis major muscle. (c, d) Findings on axial T2-weighted (c) and contrast-enhanced fat-saturated T1-weighted (d) MR images of the left breast and chest wall (obtained to evaluate lesion extent and to exclude any concerning features that might suggest a more aggressive lesion, such as areas of soft-tissue signal intensity or nodular enhancement) help confirm a diagnosis of intramuscular lipoma (arrow).
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Figure 18. Imaging of a 24-year-old woman who was referred with a palpable axillary mass and left arm paresthesias. (a) Coronal contrast-enhanced fat-saturated T1-weighted MR image of the left shoulder (obtained previously) shows an enhancing left axillary mass (black arrow) close to the axillary neurovascular bundle (white arrow). Axillary US was recommended by the musculoskeletal radiologist to rule out a vascular malformation. (b) Short-axis left axillary color Doppler US image (obtained in the breast imaging department) shows a mass (arrow) displacing and compressing the adjacent axillary vessels (arrowheads) but no evidence of flow to suggest a vascular origin. The breast imager referred the patient to an orthopedic surgeon specializing in oncology. Results of a core biopsy, performed by a musculoskeletal radiologist after consultation with the surgeon, demonstrated nodular fasciitis.
Figure 19. Imaging of a 53-year-old woman with a palpable left breast mass and negative mammographic findings. (a) Long-axis gray-scale US image shows a hypoechoic mass (white arrow) insinuating between two adjacent ribs (white arrowheads) and abutting the pleural surface (black arrowhead). The mass displaces the pectoralis muscle anteriorly (black arrow). Because of the chest wall origin, the breast imager recommended breast MR imaging for further characterization and localization instead of breast mass biopsy. (b) Sagittal contrast-enhanced fat-saturated T1-weighted MR image shows an enhancing solid mass (arrow) centered in the chest wall and extending into the breast tissue. A biopsy performed at an outside institution revealed desmoid fibromatosis. The patient was referred to a surgeon specializing in soft-tissue tumors.
increase patient morbidity (17). If an arteriovenous fistula, aneurysm, or other vascular malformation is suspected, a vascular surgery consultation is more appropriate. By suggesting the appropriate clinical referral on the basis of the US findings, the breast imager benefits the primary care provider and the patient and facilitates timely diagnosis and, if necessary, treatment. Suggested algorithms for patient management when a non–lymph node axillary or nonmammary chest wall lesion is identified are shown in Figure 20.
Conclusion
At US of the breast and axilla, lesions of nonmammary and non–lymph node origin will sometimes be encountered by the breast imager. Although not all of these lesions can be differentiated from primary mammary or lymph node processes, understanding the anatomy of the chest wall and axilla, using a standardized US technique, and recognizing specific anatomic imaging clues will help imagers identify and differentiate such lesions. Formulating an appropriate differential diagnosis
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Figure 20. Diagrams show suggested patient care algorithms when an axillary lesion of non– lymph node origin (a) or a chest wall lesion of nonmammary origin (b) is encountered. AVM = arteriovenous malformation, MRI = MR imaging, +/− = with or without.
is critical to ensuring proper patient management and avoiding unnecessary treatment delays and inadvertent patient morbidity.
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ing upper-extremity block anesthesia. Skeletal Radiol 2013;42(5):707–713. 9. Giess CS, Raza S, Birdwell RL. Distinguishing breast skin lesions from superficial breast parenchymal lesions: diagnostic criteria, imaging characteristics, and pitfalls. RadioGraphics 2011;31(7):1959–1972. 10. Resnick D. Diagnosis of bone and joint disorders. 4th ed. Philadelphia, Pa: Saunders, 2002; 4148–4151, 4161–4170. 11. Jeung MY, Gangi A, Gasser B, et al. Imaging of chest wall disorders. RadioGraphics 1999;19(3):617–637. 12. Tateishi U, Gladish GW, Kusumoto M, et al. Chest wall tumors: radiologic findings and pathologic correlation. I. Benign tumors. RadioGraphics 2003;23(6):1477–1490. 13. Tateishi U, Gladish GW, Kusumoto M, et al. Chest wall tumors: radiologic findings and pathologic correlation. II. Malignant tumors. RadioGraphics 2003;23(6):1491–1508. 14. Horvai, Andrew. Bones, joints, and soft tissue tumors. In: Kumar V, Abbas AK, Aster JC. Robbins and Cotran pathologic basis of disease. 9th ed. Philadelphia, Pa: Saunders, 2015. 15. Reynolds DL Jr, Jacobson JA, Inampudi P, Jamadar DA, Ebrahim FS, Hayes CW. Sonographic characteristics of peripheral nerve sheath tumors. AJR Am J Roentgenol 2004;182(3):741–744. 16. Privette A, Fenton SJ, Mone MC, Kennedy AM, Nelson EW. Desmoid tumor: a case of mistaken identity. Breast J 2005;11(1):60–64. 17. Wiesel S. Operative techniques in orthopaedic surgery. Philadelphia, Pa: Lippincott, Williams & Wilkins, 2011; 1719–1727.
TM
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