CASE 2 Extensive intraductal carcinoma presenting as a palpable, tumor-filled ductal system

A 74-year-old woman was evaluated for right upper inner quadrant (UIQ) palpable firmness. Mammography showed a segmental region of tubular nodularity with suspicious microcalcifications, spanning 5 cm, extending from the retroareolar region to the UIQ (Figures 1 and 2). On ultrasound, dilated retroareolar soft tissue containing ducts extended into the UIQ (Figure 3). Ultrasound-guided biopsy obtained intermediate-grade intraductal carcinoma with papillary and cribriform features. The patient was a part-time resident of the area and had multiple medical problems, including severe atherosclerotic disease with prior coronary artery bypass graft, stents, and abdominal aortic aneurysm repair. She elected treatment with partial mastectomy and interstitial brachytherapy (Figure 4).

FIGURE 1 Mediolateral oblique (MLO) (A) and CC (B) mammograms show heterogeneous parenchymal density. A variety of coarse, scattered, benign calcifications are seen. A segmental zone of increased density is seen in the right UIQ. Note the marked asymmetry of the medial breasts in the CC projection. The left breast is largely fatty medially.

FIGURE 2 Magnification views of the right UIQ [lateral (A) and CC (B)] show a marker (arrowheads) delineating the location of the palpable abnormality. Thickened tubular structures suggesting abnormally distended ducts are particularly well depicted in the CC projection. Clusters of indeterminate microcalcifications project within these abnormal ducts (largest indicated by arrow).

FIGURE 3 Ultrasound images show the correlating sonographic abnormality. A, Branching distended retroareolar ducts are filled with soft tissue. Blood flow within the echogenic ductular contents delineates it from complex fluid. B, Ectatic tubular structures containing hypoechoic tumor extend into the UIQ. C, Punctate echogenic foci (calcification) can be seen within the hypoechoic solid tumor distending these ectatic ducts (arrows). D, A hypoechoic mass, with microlobular borders and echogenic punctate microcalcifications, is the largest discrete abnormality at the level of the palpable firmness (arrow). E, Vascular flow is readily demonstrated within the distended ducts in the UIQ as well as at the retroareolar level.

FIGURE 4 Specimen radiograph contains most of the mammographic abnormality. A conventional localization procedure was not performed because the lesion was palpable as a cord-like abnormality.

The pathology showed two negative sentinel lymph nodes. A 0.9-cm mucinous (colloid) carcinoma was found, with extensive (6 cm) intermediate-grade DCIS extending into lobules, estrogen receptor and progesterone receptor positive, HER-2/neu negative. The margins were focally positive for DCIS posteriorly, and multiple margins were close (<1 mm) for DCIS.

TEACHING POINTS

This imaging manifestation of extensive DCIS is not commonly seen. The involved ductal system could easily be visualized because of its expansion and filling by intraductal tumor. Microcalcifications were a feature of this abnormality, but not as impressive a component as the mammographically dense and cord-like distended ductular system. The sonographic findings of vascular, tumor-filled branching ducts are well within the spectrum of described possible imaging manifestations of intraductal tumor, but such clear depiction is uncommon. The utility of color Doppler to reveal vascularity, allowing differentiation of hypoechoic solid tissue from complex fluid, is well demonstrated here.

CASE 3 BRCA1 patient, abnormal whole-body PET leading to diagnosis of DCIS

A 53-year-old woman with a past medical history of right breast cancer 15 years before and ovarian cancer 5 years previous, underwent positron emission tomography (PET)/CT for surveillance of ovarian cancer. Her prior breast cancer was infiltrating ductal carcinoma (IDC), which had been treated with lumpectomy and radiation. Whole-body PET/CT showed asymmetrical, relatively focal, mildly increased uptake in the left lateral breast (Figure 1). Correlation with a recent mammogram showed no corresponding abnormality. Left breast ultrasound was also negative.

FIGURE 1 Whole-body PET images show focal, asymmetrical, mildly increased, left lateral breast uptake of FDG (cursors).

Breast MRI was obtained 6 months later. Segmental, clumped, plateauing enhancement was found in the left lateral breast (Figures 2, 3, and 4). A positron emission mammography (PEM) scan with fluorodeoxyglucose (FDG) was obtained as well (Figures 5 and 6).

FIGURE 2 Axial maximal intensity projection breast MRI view from early in the enhanced, dynamic series shows localized, segmental, clumped left lateral breast enhancement. The right breast is smaller than the left from prior lumpectomy for IDC.

FIGURE 3 Sagittal, subtracted, enhanced images (A lateral to B) show a suspicious pattern of enhancement, with clumped, linear, ductal distribution.

FIGURE 4 Enhancement pattern is graphically represented by color overlay (A) and signal intensity change–time curve (B), showing plateauing enhancement.

FIGURE 5 Representative PEM images of the left breast, MLO projection. In the upper breast, mild, segmental increased metabolic activity is seen.

FIGURE 6 PEM images of the left breast, CC projection. The LCC marker indicates the lateral side. Segmental uptake of FDG corresponding to the MRI abnormality is seen laterally.

MRI-guided biopsy was performed (Figure 7). Pathology showed high-grade ductal carcinoma in situ (DCIS), with comedonecrosis and cribriform types, and lobular cancerization and multiple foci suspicious for microinvasion. The tumor was estrogen receptor and progesterone receptor negative.

FIGURE 7 Digital mammographic images [90-degree lateral (A) and CC (B)], obtained after performance of MRI-guided biopsy, show the clip projecting in the upper outer quadrant. A large coarse benign calcification associated with a fibroadenoma also projects in the lateral breast. No mammographic abnormality is identifiable in the area of the MRI and PET abnormality.

Subsequently, the patient underwent BRCA gene testing and was confirmed to have a BRCA1 genetic mutation. Her mother and sister had previously had breast cancer.

Breast conservation was attempted, with initial lumpectomy and subsequent margin re-excision both showing DCIS at the margins.

TEACHING POINTS

During these evaluations, the patient was not known to be a BRCA1 mutation carrier. Her personal history of both breast and ovarian cancer and strong family history of breast cancer in both her mother and sister certainly suggested genetic predisposition. Interestingly, the initial results of BRCA testing of this patient were negative, but retesting proved her to be BRCA1 positive.

The patient’s high-grade DCIS was picked up as an unsuspected finding on whole-body PET scan, obtained for surveillance for ovarian cancer. Initial workup with mammography and sonography showed no correlate. Breast MRI is the appropriate next breast imaging step in the evaluation, given the patient’s high risk profile and the unexplained PET scan finding.

The MRI pattern of segmental, clumped enhancement along a ductal ray is highly suspicious. Because there was no mammographic or sonographic correlate, MRI-guided biopsy is the appropriate next step.

A PEM scan was also obtained in this patient, before the MRI-guided biopsy. The patient was a volunteer test subject during applications for a newly installed device. It is interesting to compare the information available from the whole-body PET study to the higher-resolution PET data obtained with PEM scanning. On whole-body PET, the breast abnormality is heralded primarily by asymmetry and focality of activity in the left breast. It is somewhat difficult to precisely localize the activity because of the supine and dependent positioning of the breasts and lack of compression. Little fine detail is available from the whole-body study, but it does alert the observer to the area requiring additional evaluation.

The PEM study is obtained in gentle compression, applied only to immobilize the breasts. Because the modality is tomographic, there is no need to thin the breast tissue as much as in mammography. The resolution of PEM is on the order of 2 mm in plane, compared with 6 mm in a state-of-the-art whole-body PET scanner. The detectors are closer to the imaged tissue than in the ring array of a whole-body scanner, being located in “compression plates” of detector arrays on either side of the breast. Projections analogous to mammographic views can be obtained.

As of this writing, PEM devices have only recently become available and are limited in distribution. There is little collective experience with the capabilities and limitations of PEM scanning. A multicenter prospective trial comparing the performance of PEM to breast MRI in preoperative staging of newly diagnosed breast cancers is accruing patients, and data from this trial will hopefully help in delineating the appropriate role of PEM in the breast imaging armamentarium.

CASE 7 Invasive lobular carcinoma

A 68-year-old woman presented with left breast nipple retraction and palpable fullness. Mammographic views demonstrated increased density in the medial subareolar left breast and mildly prominent left axillary nodes (Figures 1, 2, 3, and 4). Ultrasound of the left breast demonstrated scattered areas of acoustic shadowing and small solid masses (Figures 5 and 6). MRI revealed diffuse abnormal enhancement of the central left breast as well as enlarged left axillary nodes (Figures 7 and 8). Subsequent ultrasound-guided core needle biopsy of multiple areas of the left breast confirmed multicentric invasive lobular carcinoma. The patient was treated surgically with mastectomy and lymph node dissection.

FIGURE 1 Right MLO mammographic view shows scattered glandular tissue, with no abnormality.

FIGURE 2 Left MLO mammographic view. Left axillary lymph nodes appear mildly prominent. The nodes are somewhat dense for size and demonstrate mild cortical thickening (arrow). Asymmetrical reticular subareolar density is noted.

FIGURE 3 Right CC mammographic view shows no abnormality.

FIGURE 4 Left CC mammographic view. There is increased density in the medial subareolar left breast (arrow). There is also a slight generalized increase in breast tissue density compared with the right.

FIGURE 5 Ultrasound of the medial subareolar left breast. There is a 4-mm, ill-defined, taller-than-wide, solid mass, with a hyperechoic rim (arrow) as well as areas of mild acoustic shadowing.

FIGURE 6 Ultrasound image of the central left breast. Multiple areas of acoustic shadowing are seen (arrow). A discrete mass is not seen.

FIGURE 7 Postcontrast, subtracted, axial MRI of the breasts. MRI reveals diffuse nonmass enhancement of the central left breast.

FIGURE 8 Maximal intensity projection subtracted MRI view of both breasts shows extensive abnormal left breast enhancement, along with abnormally enlarged and enhancing left axillary lymph nodes (arrow).

TEACHING POINTS

Invasive lobular carcinoma represents about 10% of all invasive breast cancers. However, because they are frequently diffusely infiltrating and may not present as a discrete mass, they can be difficult to detect. In addition, invasive lobular carcinoma has a higher rate of multicentricity and bilaterality than ductal carcinoma. This example of invasive lobular carcinoma illustrates the limitations of mammography and ultrasound to accurately delineate the extent of breast involvement in some cases.

CASE 9 ILC presenting as a mass; postoperative changes on CT and PET

A 51-year-old asymptomatic woman underwent routine mammographic screening, which suggested a possible 1-cm mass overlying the pectoral muscle on the left MLO view. Additional mammographic spot compression and ultrasound confirmed a suspicious abnormality (Figure 1). Biopsy with ultrasound guidance confirmed infiltrating lobular carcinoma (ILC).

FIGURE 1 Ultrasound of the left lateral breast at 3 o’clock shows a highly suspicious 9-mm mass. Malignant features displayed by this tumor include marked hypoechogenicity, angular and irregular margins, taller-than-wide shape, faint shadowing, and vascularity.

Because of the ILC histology, breast MRI was obtained preoperatively to screen the opposite breast and evaluate the extent of the known ILC (Figures 2, 3, and 4). The known left lateral ILC manifested as an 11-mm irregularly marginated mass with plateauing enhancement. Anteromedial to the index tumor was an additional enhancing 5-mm nodular focus, also with plateauing enhancement.

FIGURE 2 Axial enhanced, subtracted, maximal intensity projection MRI of both breasts shows the index ILC in the posterior left lateral breast. There is a background pattern of scattered, stippled fibrocystic enhancement. On the left, a few of the scattered foci of activity are more prominent, including a 5-mm focus anterior to the index ILC.

FIGURE 3 Enhanced, subtracted section through the left lateral index ILC, which is irregularly marginated. Anterior to it is a 5-mm nodular focus of enhancement.

FIGURE 4 Sagittal, enhanced, fat-saturated section through the left lateral breast shows the relation of the index ILC posteriorly and the 5-mm additional focus anterior to it. On this delayed series (5 minutes after contrast injection), there appears to be a localized region of low-level parenchymal enhancement in the immediate vicinity, connecting the two lesions.

At the time of presentation for ultrasound-guided needle localization, a second-look ultrasound showed a 3-mm indeterminate sonographic finding near the index lesion (Figures 5 and 6). This seemed to correlate with MRI and was needle-localized at the same time.

FIGURE 5 Second-look ultrasound of the left breast, on the day of needle localization, shows a 3-mm nodular focus with irregular margins in a corresponding location (arrow).

FIGURE 6 Additional left ultrasound image from the same study shows the relationship of the new finding to the known ILC. Both were needle localized with ultrasound guidance.

Pathology of the lumpectomy specimen showed a 2.7-cm ILC. Note was made by pathology that this dimension was obtained by measuring off the glass slides of the embedded specimen and was larger than the gross tumor, which measured 11 mm. The tumor was estrogen receptor and progesterone receptor positive and HER-2/neu negative. Margins were negative. Sentinel lymph node sampling showed two of six lymph nodes to have metastases, the largest 5 mm.

Axillary dissection performed 2 weeks later obtained 14 additional lymph nodes, all negative for tumor, for a total of 2 of 20 lymph nodes involved.

Because of the nodal involvement, systemic staging studies were obtained, including bone scan and PET/CT. PET/CT showed changes compatible with a 1-week-old axillary dissection, as well as 3-week-old postlumpectomy changes (Figures 7, 8, and 9).

FIGURE 7 Coronal PET/CT images, obtained 1 week after left axillary dissection, show linear hypermetabolism at the operative level.

FIGURE 8 Sagittal PET/CT images through the left lateral breast and axilla show photopenia with a faint metabolically active rim in the left breast at the site of a 3-week-old postoperative seroma. More intense linear hypermetabolism is seen at the level of the 1-week-old left axillary dissection site.

FIGURE 9 Corresponding contrast-enhanced chest CT images through the axilla (A) and the breasts (B). A, Surgical clips are seen in the left axilla, with ill-defined soft tissue density at the site. Axillary dissection was 1 week prior. B, Postoperative seroma in the left lateral breast is seen from surgery 3 weeks before. Scatter from the arm at the patient’s side is noted.

TEACHING POINTS

How do we account for the apparent size discrepancy between the tumor seen on mammography, sonography, and MRI, which measured 1.1 cm, and the tumor at final pathology, which measured 2.7 cm? In this case, the gross tumor mass corresponded well to the size predicted by imaging evaluations.

If we measure the tumor size (from the sagittal MRI, Figure 4), and include both the 11-mm known ILC and the 5-mm “satellite” lesion anterior to it, and encompass the tissue between, we obtain a dimension of 2.7 cm. We know ILC can be variable in enhancement intensity on MRI. Presumably, some of this ILC did not enhance much. Conferring with the pathologist helps to suggest a resolution to questions of this nature. In this case, the gross specimen was sectioned, divided by the number of sections taken, with the tumor size estimate resulting from the number of sections taken multiplied by the number with tumor. The tumor had areas of infiltrating lines of tumor cells into fat and surrounding normal breast ducts. We can hypothesize with this information that the two tumor nodules seen on imaging represent foci within continuous tumor from the pathologic standpoint.

Review of this case suggests that the good outcome of negative margins on the first lumpectomy attempt had an element of luck involved. If there had not been an ultrasound correlate visualized for the satellite lesion suggested on MRI, which was localized at the same time as the index lesion, the desired outcome of negative margins might not have been so readily achieved.

Typical postoperative changes are demonstrated in this patient on both CT and PET. The inflammatory and reparative cellular response to surgery is visualized on FDG PET because white blood cells, typically activated monocytes, utilize glucose for fuel. The intensity of the activity at these operative sites of differing age seems proportionate, with less intense activity at the 3-week-old breast surgical site than at the 1-week-old axillary dissection level.

CASE 10 ILC presenting as architectural distortion

A 78-year-old female with two prior benign right breast biopsies had increased architectural distortion noted at the right 6-o’clock level on screening mammography (Figure 1). This was near a 20-year-old excisional biopsy site. Increased density and architectural distortion was confirmed on spot compression (Figure 2), and sonography demonstrated a corresponding shadowing mass (Figure 3). Ultrasound-guided core needle biopsy confirmed infiltrating lobular carcinoma (ILC). Because of the ILC histology, preoperative breast MRI was performed and showed the opposite breast to be clear. The known ILC manifested as a spiculated region of progressive intense enhancement, with no other sites of disease (Figure 4).

FIGURE 1 MLO (A) and CC (B) mammograms show heterogeneously dense parenchyma. The right (R) breast is smaller than the left (L) from prior benign surgical biopsies. An oil cyst from prior surgery in seen in the upper inner quadrant. Architectural distortion is seen inferiorly on the right, at the 6-o’clock level.

FIGURE 2 Additional mammographic views confirm increased density, spiculation, and architectural distortion at the 6-o’clock level. A, 90-degree lateral view of the right breast. A scar marker had been placed in the upper breast, at the site of an excisional biopsy from 4 years before. Subjacent fat necrosis is seen (coarse benign calcification and oil cyst). B, 90-degree lateral spot view. C, CC spot view.

FIGURE 3 Ultrasound of the lower central breast (two views, A and B) showed a vascular, irregularly marginated, shadowing, hypoechoic mass corresponding to the region of architectural distortion on mammography. This was near the level of an old benign surgical excisional biopsy scar. No extension to the skin was seen.

FIGURE 4 Axial (A) and sagittal (B), enhanced, subtracted breast MRIs of the right breast show the intensely enhancing, spiculated mass to be solitary and unifocal.

The patient elected to undergo mastectomy because the right breast was already smaller than the left (from the two prior benign biopsies) and a good cosmetic result seemed unlikely. The specimen contained a 2.5-cm ILC, estrogen receptor and progesterone receptor positive, HER-2/neu negative, with clear margins and two negative sentinel lymph nodes. Final stage was stage II, T2N0M0, and the patient was started on anastrozole (Arimidex).

TEACHING POINTS

Surgical scars can be tricky to evaluate. The correlation among location, appearance, and expected behavior needs to be fairly precise. Unexpected behavior (increase in prominence, density, or conspicuity on mammography) should be investigated. Ultrasound should be carefully correlated as well. This focus of shadowing did not extend to the skin surface, as most scars can be shown to do, and the increased vascularity is a tip-off that this needs further investigation. A normal old scar should not be this vascular. If there is persistent ambiguity after mammographic and sonographic evaluations, breast MRI can be very helpful in further assessment.

In this case, the diagnosis of ILC was established by ultrasound-guided core needle biopsy, and MRI was obtained to assess the extent of the known ILC and to evaluate the opposite breast. ILC has a known propensity for bilaterality, up to 30%, and is a clear indication for breast MRI. The morphology of the ILC enhancement is abnormal, with irregular, spiculated margins, and correlates well with the mammographic and sonographic manifestations of this tumor. The enhancement pattern was progressive, which is more typical of ILC than IDC. As many authors have previously noted, morphology should trump kinetic information. Kinetic data are most helpful when it is abnormal and may increase one’s suspicion level regarding morphologically bland-appearing findings. Conversely, kinetic data that suggest benignity (progressive enhancement) should not reassure one about a morphologically concerning finding.

In this patient, breast MRI suggested she was a lumpectomy candidate based on extent of disease (unifocal). However, given the size of the lesion relative to the breast size, her preexisting asymmetry from prior surgeries, and its location in the inferior breast, a bad cosmetic result with partial mastectomy and radiation can be anticipated, and the patient opted for mastectomy.

CASE 11 ILC presenting as a palpable, predominantly hyperechoic ultrasound mass

A 55-year-old woman was referred for evaluation of firmness palpated in the right medial breast. Mammography showed heterogeneous increased breast parenchymal density, but suggested a probable mass at the level in question (Figures 1, 2, and 3). Ultrasound confirmed a discrete mass with an unusual sonographic appearance, being predominantly hyperechoic (Figure 4). The diagnosis of invasive lobular carcinoma (ILC) was made by palpation-guided core biopsy. Because of the breast parenchymal density and histology of ILC, the patient was further evaluated for breast conservation therapy with MRI. Breast MRI showed the known right ILC to have malignant features, including rim enhancement and washout (Figure 5). No indication of additional malignancy was seen in the right breast, with only scattered, fibrocystic-type tiny foci of enhancement noted. The left breast showed two small, sub-centimeter enhancing masses adjacent to each other in the anterior medial retroareolar breast (Figure 6). Ultrasound showed possible correlates of round hypoechoic masses (complex cysts versus solid masses by ultrasound) (Figure 7), which were subsequently needle-localized for excision at the time of contralateral mastectomy, and proven benign. The left breast pathology showed fibrocystic change and sclerosing adenosis. The right mastectomy specimen showed a 1.3-cm ILC, estrogen receptor and progesterone receptor positive, HER2/neu negative, with one negative sentinel node. Because of a close surgical margin, the patient was also treated with chest wall radiation with a boost to the surgical bed.

FIGURE 1 MLO (A) and CC (B) mammograms show heterogeneous increased breast density. A radiopaque marker has been placed to identify the site of a palpable right lower inner quadrant lump. A corresponding mass is suggested, but blends into the dense adjacent parenchyma. A double density at the site is suggested on the CC view.

FIGURE 2 A 90-degree lateral view more convincingly shows an inferior mass of increased density at the level of the marker. Although the inferior margin appears circumscribed, the posterior and superior margins are obscured by adjacent parenchyma, into which the mass blends.

FIGURE 3 Spot compression in the MLO projection shows that the mass fails to compress or change shape.

FIGURE 4 Ultrasound of the palpable mass shows an unusual appearance. The mass is lobular in shape, but with ill-defined margins and no definable capsule. The mass is predominantly hyperechoic, but shows hypoechogenicity centrally and peripherally.

FIGURE 5 Axial maximal intensity projection of an early run from the enhanced dynamic breast MRI series shows the known ILC in the right medial breast. Rim enhancement, a morphologic feature of malignancy, is well demonstrated. Two small, adjacent, benign-appearing, enhancing masses are seen in the anterior medial left breast, behind the nipple.

FIGURE 6 Enhanced subtracted axial image (A) shows one of the two sub-centimeter, indeterminate masses in the left medial retroareolar breast. Corresponding axial STIR image (B) shows scattered, small bilateral cysts. The enhancing small nodule is of the same signal intensity as the breast parenchyma, but not nearly so bright as the adjacent cyst. The other lesion showed very similar signal intensity.

FIGURE 7 Ultrasound of the region in question on MRI on the left shows two adjacent round hypoechoic complex cysts vs. small solid nodules. These were needle-localized at the time of surgery for the contralateral ILC, and histology was benign, showing fibrocystic change and sclerosing adenosis.

TEACHING POINTS

ILC represents up to 15% of all breast cancers and frequently is more difficult to diagnose than infiltrating ductal carcinoma. Clinically, it can be occult. Conversely, when it does present as a palpable mass, the clinical findings can at times be more impressive than the imaging findings, which can be relatively subtle. For this reason, clinically impressive palpable masses should be considered for palpation-guided biopsy, if the imaging evaluation is negative. Classically, ILC on histology grows as lines of tumor cells, extending tendrils through the parenchyma in single-file manner. This growth pattern underlies the difficulty that can be encountered in diagnosing ILC on imaging. Because there may not be a concentrated mass of confluent tumor cells, 15% of ILC may manifest on mammography as architectural distortion alone (sometimes best seen on a CC projection), without a true mass at the center. On ultrasound, ILC producing architectural distortion may manifest as an area of ill-defined shadowing, where margins of a mass are difficult to define. On MRI, enhancement of an ILC growing in this manner may be subdued and segmental compared with ILC- and IDC-forming masses. This growth pattern may also contribute to the positron emission tomography tendency of ILC to be less hypermetabolic than IDC.

That said, at least 40% of ILCs do form a mass, and in this presentation, the imaging findings parallel those of IDC. This is such a case. The mass is suspected based on mammography, but poorly delineated from the dense parenchyma. The ultrasound appearance is interesting, being predominantly hyperechoic. It fails Stavros’ criteria for benignity by virtue of being heterogeneous, with hypoechogenicity centrally and peripherally. As Stavros noted, hyperechoic masses usually are benign, but they must be uniformly hyperechoic to be characterized as benign. This appearance is not specific, and a very similar-appearing echogenic IDC is presented as a companion case in this chapter (Case 12).

The MRI features are malignant, with rim enhancement and washout. The MRI performed axially provides an opportunity for simultaneous evaluation of the opposite breast. Given both the propensity of ILC to be bilateral (up to 28% of the time) and the conventional breast imaging limitations in delineating the full extent of ILC, MRI is advocated for routine preoperative local staging of a new diagnosis of ILC, while simultaneously screening the other high-risk breast. Of course, not every focus of enhancement that turns up on breast MRI is cancer, and the use of breast MRI in such imaging evaluations will require follow-through and further workup of additional findings of concern on MRI. In this case, two small, adjacent, subcentimeter, benign-appearing but indeterminate nodules were seen on the opposite side. Ultrasound found suggestive correlates, which could have been sampled preoperatively with ultrasound guidance, but which in this case were needle-localized at the time of the contralateral lumpectomy, and proved benign. The significance of small enhancing masses like these on MRI should not be underestimated. See Case 14 in Chapter 1 for similar-appearing findings that proved to be malignant.

CASE 12 Echogenic breast cancer

A 78-year-old woman presented with a palpable left breast mass. Mammography confirmed a round mass in the lateral left breast. Ultrasound demonstrated an ill-defined, mixed echogenicity lesion, corresponding to the palpable mass (Figures 1 and 2). Core needle biopsy was performed and confirmed a low-grade invasive ductal carcinoma. The patient was treated surgically with lumpectomy.

FIGURE 1 Ultrasound radial image of the 3-o’clock left breast palpable mass demonstrates a mixed echogenicity, solid mass. The lesion demonstrates a hyperechoic halo or rim (arrow). The mass has indistinct margins and some posterior acoustic through-transmission.

FIGURE 2 Ultrasound antiradial image of the left breast mass demonstrates that there is a central hypoechoic region within the lesion (arrow).

TEACHING POINTS

This case illustrates an example of invasive carcinoma with features that could potentially be misinterpreted as benign. When sonography demonstrates a purely hyperechoic lesion as the cause for a mammographic or palpable finding, it is almost certainly benign. However, one should perform close inspection for a hypoechoic component within the lesion because some small low-grade cancers may have an outer hyperechoic halo. In this example, the mass is clearly not purely hyperechoic and should not be confused with benign entities such as a lipoma.

CASE 13 ILC treated with neoadjuvant chemotherapy

An asymptomatic 40-year-old woman with dense breasts underwent a routine screening mammogram (Figure 1). This raised a question of an abnormality on the left. Spot compression and ultrasound confirmed a 1.4-cm suspicious mass in the left lateral breast at 3 o’clock (Figures 2 and 3). Ultrasound-guided biopsy proved infiltrating lobular carcinoma (ILC), estrogen receptor and progesterone receptor positive, HER-2/neu negative.

FIGURE 1 Screening mammograms [MLO (A) and CC (B)] show dense breast parenchyma. A possible mass was identified (arrow) in the posterior upper breast on the MLO view.

FIGURE 2 Spot compression mammographic views [MLO (A) and exaggerated CC (B)] confirm an incompressible area of increased density and architectural distortion in the posterior upper outer quadrant, best seen on the exaggerated CC spot view (arrow).

FIGURE 3 Ultrasound of the posterior lateral left breast at 3 o’clock shows a very hypoechoic, solid, taller-than-wide mass with angular and irregular margins and no capsule, corresponding to the mammogram (right cursor). A few centimeters away (left cursor), there is a more subtle abnormality, with a vague, hypoechoic, nodular, smaller mass, which disrupts the normal breast tissue architecture. The smaller focus was not appreciated prospectively but was identified on second look after breast MRI was performed. Biopsy with ultrasound guidance of this second area also showed ILC, and was marked with a clip.

Because of the ILC histology and the breast density, breast MRI was performed to evaluate the full extent of disease in the involved breast and to screen the contralateral side (Figures 4, 5, and 6). Breast MRI showed the known index tumor in the posterior lateral left breast as an irregularly marginated, intensely rim-enhancing mass, with washout. Anterior to the known ILC was an additional 1-cm enhancing mass, as well as linear and clumped enhancement in a segmental distribution, extending anteriorly toward the nipple over an expanse of 6 cm.

FIGURE 4 Axial enhanced, subtracted breast MRI shows two left lateral intensely enhancing masses, which are 2.5 cm apart. The more posterior mass (the index ILC) shows rim enhancement, and the smaller, more anterior mass is irregularly marginated. In addition, there is segmental linear enhancement between the two masses and extending anteriorly, toward the nipple.

FIGURE 5 A more inferior axial, enhanced, subtracted breast MRI shows the angular and irregular margins of the known ILC mass in the posterior left lateral breast. Linear, duct-type enhancement extending anteriorly toward the nipple is well depicted on this slice.

FIGURE 6 Angiogenesis color map of these abnormalities [A, region of interest (ROI) on the anterior mass; B, ROI on the posterior known ILC mass; C, representative signal intensity change–time enhancement graph] shows intense, early enhancement of these masses, with red indicating washout, as graphically depicted in C.

The breast MRI results strongly suggested extensive, multifocal disease throughout the left lateral breast, indicating the patient was likely unsuitable for breast conservation therapy. To confirm multifocal disease, a second-look ultrasound was performed to determine whether a correlate for the additional disease suggested by MRI could be found. A subtle corresponding nodular focus was found anterior to the index lesion, and biopsy was performed with ultrasound guidance, also confirming ILC (see Figure 3). A clip was placed to mark the site.

The patient was strongly desirous of breast conservation and elected to undergo neoadjuvant chemotherapy. She was first staged with positron emission tomography (PET)/CT and contrast enhanced chest, abdomen, and pelvis CT, which showed only faint increased metabolic activity of the known left breast ILC (Figures 7 and 8). Four cycles of doxorubicin (Adriamycin) and cyclophosphamide (Cytoxan), and four cycles of docetaxel (Taxotere) were administered, with repeat imaging assessment obtained at the midpoint and completion of chemotherapy (Figures 9, 10, 11, and 12). A partial response to chemotherapy was observed. The index lesion declined in size on ultrasound, although there was a persistent sonographically visible and vascular mass at final assessment. Serial breast MRI showed improvement as well, with progressive reduction in the size of the measurable masses, decline in enhancement intensity, and change in enhancement curve shape. There appeared to be considerable residual disease at final imaging assessment. Breast conservation was successfully achieved. Her lumpectomy specimen showed a 5-cm ILC, with no lymphovascular invasion and negative margins. Lymph node sampling showed five negative nodes. Additional treatment in the form of radiation and tamoxifen was begun subsequently.

FIGURE 7 Axial PET/CT images (A and B) (left, fused PET/CT; right, attenuation corrected PET) show faint increased activity (only minimally increased over normal breast parenchymal background) in the left lateral breast at the site of the known multifocal ILC.

FIGURE 8 Contrast-enhanced chest CT images (A to C, from above to below, adjacent slices) show faint enhancement in the left lateral breast at the site of the known multifocal ILC. Slice A shows adjacent dots of enhancement, whereas B shows a clip placed at second-look ultrasound adjacent to an enhancing 1-cm mass, confirmed by biopsy to be a second focus of ILC. Slice C, just below A and B, shows the larger, faintly enhancing index ILC in the posterior left lateral breast.

FIGURE 9 Repeat breast MRI, 4 months later, after four cycles of chemotherapy, shows evidence of a partial response to chemotherapy. Smaller masses show less intense enhancement, with enhancement curves now demonstrating a plateauing pattern and no washout. A, DynaCAD color map of the smaller anterior mass. B, Corresponding signal intensity–time curve shows blunted early enhancement and plateauing pattern. C, DynaCAD color map of the index posterior left lateral ILC mass. D, Corresponding signal intensity–time curve shows plateauing enhancement.

FIGURE 10 Third breast MRI, 2 additional months later, near the end of completion of chemotherapy, shows further reduction in size and intensity of enhancement of the residual masses. There continues to be regional linear enhancement. A, Unsubtracted, enhanced, fat-saturated, axial slice shows susceptibility artifact at the clip site, anterior to the residual index lesion (arrow). B, Subtracted, enhanced, fat-saturated, axial slice at the same level better shows the residual enhancement. C, Sagittal, enhanced, fat-saturated view through the left lateral breast shows the relationship of the residual enhancing masses to each other, aligned in an axis toward the nipple.

FIGURE 11 Serial ultrasound images of the index ILC mass, for comparison. A, At initial diagnosis, before chemotherapy. B, Midway through chemotherapy. C, Nearing completion of chemotherapy. Hypoechoic, irregularly marginated, taller-than-wide mass persists, with vascularity, although it has declined in size. The more subtle, additional lesion anterior to the index lesion became difficult to identify, although the clip could be visualized (not shown).

FIGURE 12 Serial enhanced, subtracted, axial maximal intensity projection views from the breast MRIs performed before, during, and toward the end of chemotherapy, for comparison. A, At initial diagnosis, before chemotherapy. B, Midway through chemotherapy. C, Nearing completion of chemotherapy. Progressive decline in size and intensity of enhancement, without complete imaging resolution, is demonstrated.

TEACHING POINTS

This case provides many opportunities for discussion of some of the issues raised by an ILC diagnosis. This is a mammography screening success story, with mammography successfully raising alarm bells that this was a patient who needed additional imaging. Although it did not delineate the full extent of the disease, owing in part to the breast density, it succeeded in its screening role to identify the tip of a neoplastic iceberg. Prospective ultrasound, as is frequently the case, successfully found the index lesion and served to guide a biopsy to make the diagnosis, but did not prospectively demonstrate the full extent of involvement.

The role of breast MRI is well established as a valuable adjunct to better local staging of new ILC diagnoses. Not hindered by breast density, breast MRI can also (if performed bilaterally, usually in the axial plane) effectively screen the opposite breast for occult tumor, which occurs up to 10% of the time.

In this case, much more extensive local involvement was convincingly demonstrated. The MRI pattern seen in this case, with multiple lesions, connected by enhancing strands, is among the more common patterns of ILC presentation on MRI. With the MRI in hand as a roadmap, more subtle sonographic correlates may be identifiable as targets for biopsy, allowing confirmation of multifocal disease.

With larger tumors and patients who are highly motivated for breast conservation, and therefore neoadjuvant chemotherapy, clip placement should be considered at the time of staging biopsy. It is difficult to predict the completeness of response of any one patient to neoadjuvant chemotherapy, but it should be anticipated that some patients will have complete imaging responses, which would be difficult to localize for excision without a marker in place. Pre-emptive clip placement in possible neoadjuvant chemotherapy candidates may potentially save the patient from being sent back for another procedure solely for that purpose.

This case also illustrates the propensity of ILC to be less fluorodeoxyglucose (FDG) avid than infiltrating ductal carcinoma (IDC), with even this sizable tumor barely visualized on PET. In such a case, the reassurance that is generally provided by a negative PET scan is considerably tempered.

Another question raised by this case is how best by imaging to monitor responses to neoadjuvant chemotherapy. In general, the modality that best demonstrates the pretreatment extent of disease will be most effective in any one patient in monitoring the response to chemotherapy. Most often, this is MRI, which has been demonstrated to be the most accurate modality in terms of correlating with pathology on lesion size and extent. However, until a consensus emerges, a multipronged approach with combinations of mammography, ultrasound, and MRI will continue to be utilized in most practices.

In the future, dedicated breast PET (positron emission mammography [PEM]) might prove to be useful in such assessments. Clearly, this will be most useful in tumors (such as most IDC) that have high FDG avidity. PEM is a small-field-of-view, high-resolution device, resembling a mammography unit, with detector arrays in compression plates. The patient is injected with FDG, which circulates for an hour (just as in whole-body PET imaging), and tomographic “maps” of the distribution of FDG within the breasts can then be obtained in projections comparable to mammographic views. The principle underlying this is just as in whole-body PET, with many tumors utilizing glucose as a fuel at a higher rate than normal tissues. Validation of this modality is ongoing and at this writing holds out the hope for the future avail-ability of a functionally based modality.

CASE 14 Stage IV ILC; presentation with liver metastases

An 81-year-old woman noted a right breast mass and nipple inversion several months after a fall down stairs. Bilateral mammography at another facility showed a 7-cm spiculated right breast mass. She was assessed initially by a breast surgeon. The clinical impression was of a locally advanced breast cancer with axillary metastases. On physical examination, she had a tethered, shrunken breast compared with opposite side, with a 7-cm palpable upper outer quadrant mass extending centrally. Dimpling of the skin above it was noted. A 2- to 3-cm firm, irregular axillary lymph node was palpated. Palpation-guided core biopsy of the breast mass and fine-needle aspiration (FNA) of the axillary lymph node were performed.

The breast mass histology was invasive lobular carcinoma (ILC), estrogen receptor and progesterone receptor positive and HER-2/neu positive. The axillary FNA was nondiagnostic, but subsequent ultrasound-guided FNA did confirm malignant epithelial cells, compatible with metastatic breast carcinoma.

The patient had little in the way of systemic complaints, other than weight loss. Because of the ILC propensity for bilaterality, breast MRI was obtained. Positron emission tomography (PET)/CT was also ordered for systemic staging, given the large size of the tumor and known axillary nodal involvement.

Breast MRI showed an extensive spiculated mass, occupying much of the upper outer quadrant (Figures 1, 2, 3, 4, and 5). A second focus of enhancing tumor at the retroareolar level was connected by an enhancing linear spicule. Multiple such linear tendrils could be seen extending from the dominant mass to the overlying skin, producing the clinically apparent dimpling. The left breast was unremarkable.

FIGURE 1 Axial maximal intensity projection view from enhanced dynamic breast MRI shows asymmetry in breast size. The left is quite pendulous, whereas the right is comparatively shrunken. Two dominant spiculated enhancing masses are seen on the right, one retroareolar and the other central and lateral. No occult breast cancer is suggested on the left.

FIGURE 2 Enhanced, subtracted, axial breast MRI shows enhancing linear extensions to the overlying skin from the enhancing lateral mass.

FIGURE 3 Sagittal, enhanced, subtracted breast MRI shows the relationship between the two main tumor masses, with linear enhancement joining them. Thin, enhancing spicules extend superiorly to the skin surface from the dominant mass. The dimpling of the skin surface resulting can be appreciated here.

FIGURE 4 Color-flow kinetics maps (A, through the dominant lateral mass; B, through the retroareolar component) show most of the enhancement pattern to be plateauing (blue). Only a tiny focus of washout was seen (not shown).

FIGURE 5 STIR axial image of the breasts shows poor detail of the liver. Subsequently demonstrated liver metastases were not suspected based on this study and are difficult to demonstrate even in retrospect.

PET/CT showed hypermetabolism in at least four right axillary lymph nodes, as well as modest activity in the right breast mass. Multiple peripherally hypermetabolic, necrotic liver metastases were also identified, indicating that the patient’s true stage was actually stage IV (Figure 6). These correlated with hypovascular, peripherally enhancing, necrotic-appearing liver metastases on enhanced CT (Figure 7). No hepatomegaly was noted on physical examination, and the patient’s liver function tests, other than an elevated alkaline phosphatase, were normal. CT-guided biopsy was performed and confirmed metastatic adenocarcinoma, consistent with breast carcinoma. Planned mastectomy was cancelled, and the patient was begun on letrozole (Femara).

FIGURE 6 PET scan images (left to right: coronal, sagittal, axial, and coronal volume projection) show increased metabolic activity in the primary right breast ILC (sagittal image), in right axillary lymph nodes (the largest and most intense is seen in the axial image), and at the periphery of necrotic liver metastases (coronal image). Note the modest level of metabolic activity of the primary ILC, despite its size.

FIGURE 7 Enhanced abdominal CT images (portal venous phase; A, near dome, and B inferior to A) show rim-enhancing, centrally low density, necrotic liver masses, typical in appearance for hypovascular metastases.

TEACHING POINTS

This case serves to demonstrate many reported features and manifestations of ILC. Classically, ILC grows by infiltration of parenchyma by single-file rows of tumor cells. One of the known presentations of ILC is the “shrinking breast.” This can be difficult to recognize on mammography (see Case 8 in this chapter for a bilateral example). In this case, breast asymmetry could be appreciated clinically, and we can appreciate the counterpart findings on MRI. Skin dimpling could also be seen on clinical examination, and the MRI shows the imaging correlate. Multiple, fine, enhancing linear tendrils of presumed tumor could be seen extending to skin surfaces on this MRI.

Another described MRI characteristic of some cases of ILC is slower contrast accumulation and lower-level enhancement intensity, also seen in this case. Although the tumor mass is quite sizable, the enhancement intensity is less than that usually seen in comparably sized infiltrating ductal carcinoma (IDC). Most of the mass showed relatively slow wash-in, with eventual plateauing enhancement at 2 to 3 minutes of 200% above baseline. Only a tiny single focus of washout was found.

A characteristic of ILC noted on PET imaging is more modest metabolic activity than IDC. Even this very sizable ILC shows only moderate metabolic activity. In this case, the involved axillary lymph nodes and liver metastases are of higher metabolic activity than the primary tumor.

Depending on the configuration of the breast MRI coil, a portion of the liver is often included in the examination. This should not be relied on to consider the liver adequately imaged for clearance of significant disease, as this case amply illustrates. Even though this patient was demonstrated subsequently to have extensive liver metastases, these were not suspected or clearly identified even in retrospect on the breast MRI. Breast MRI coils are configured to provide maximal signal anteriorly and there is a rapid drop-off in signal posteriorly. The visualized portion of the liver is also often partially obscured by phase artifact from the heart (preferentially set right to left, rather than anterior to posterior, where it would obscure breast tissue). On occasion, a liver cyst will be seen with sufficient clarity on breast MRI to characterize it (bright on STIR or T2, and nonenhancing), but this is the exception (an example is illustrated in Chapter 9, Figure 5). More commonly, the breast imager who suspects or detects a liver lesion on breast MRI (which is not known from prior studies) will need to recommend a dedicated study to characterize it (either triple-phase CT or multiphasic enhanced MRI).

CASE 15 Ultrasound findings of inflammatory cancer

A 78-year-old woman presented to her physician with a swollen and erythematous right breast. Ultrasound of the right breast revealed a suspicious, 13-mm, solid breast mass with microcalcifications (Figure 1). In addition, findings of breast edema and skin thickening were seen, suggesting an inflammatory component (Figure 2). A skin punch biopsy was positive, confirming the diagnosis of inflammatory breast carcinoma. The patient was treated with mastectomy and axillary node dissection, chemotherapy, and radiation therapy.

FIGURE 1 Ultrasound image of the right breast. There is an irregular, hypoechoic, 13-mm mass with spiculated margins. The echogenic foci within the lesion represent microcalcifications. Superficially, abnormal skin thickening is seen (arrow), and there is generalized edema.

FIGURE 2 Ultrasound image of the right breast. Multiple anechoic bands are seen in the parenchyma (arrow), representing breast edema.

TEACHING POINTS

Inflammatory breast cancer (IBC) is a rare but very aggressive form of breast cancer, associated with an adverse prognosis. Cancer involvement of the lymphatics of the breast skin is the pathologic hallmark. The diagnosis is usually suspected on clinical exam with the rapid onset of breast edema, erythema, swelling, or the classic peau d’orange skin changes. It can be difficult to distinguish breast infection from inflammatory carcinoma, both clinically and on imaging. Skin punch biopsy can be helpful to confirm a suspected clinical diagnosis of IBC but is not required if the clinical presentation is characteristic and there is biopsy confirmation of cancer from a breast lesion. The constellation of imaging findings in this case, including a suspicious breast mass, breast edema, and skin thickening, are highly suggestive of inflammatory breast carcinoma.

CASE 17 Initial identification of breast cancer during breast MRI for implant integrity

A 60-year-old woman with long-standing breast implants noted a left breast lump while lying on her left side. She had been considering implant revision. She had implants initially placed over 20 years before, with the left revised a few years later for encapsulation. A 6-mm, round, mobile mass was palpated by her physician along the medial border of the left implant. She was referred for breast implant MRI.

Because a palpable lump in an implant patient could be either a breast parenchymal mass or related to extracapsular silicone from implant failure, the study was conducted as a hybrid examination. Sequences were obtained both to evaluate the implants and to look for extracapsular silicone, with an enhanced, dynamic subtracted sequence obtained to evaluate the breast parenchyma.

The implants proved to be double-lumen silicone and saline on the right and single lumen silicone on the left (not shown). The implants appeared intact, and no extracapsular silicone was seen. The breast parenchyma showed extensive fibrocystic enhancement, with three discrete sites of more intense mass enhancement (Figures 1 and 2). One was in the left breast at 12 o’clock, with washout. Two were in the right breast, one anteriorly at 8 o’clock and one in the lower inner quadrant at 5 o’clock along the implant margin. Both of these sites showed plateauing enhancement.

FIGURE 1 Axial enhanced, subtracted, T1-weighted gradient echo images of both breasts from minute 2 of dynamic enhanced series, from above to below (A to C). A, Through the upper breasts: A small, 7-mm enhancing mass is seen on the left at 12 o’clock. Kinetic analysis showed washout (not shown). B, Through the level of the nipples: An irregularly marginated mass enhances in the right anterior lateral breast. Kinetic analysis showed a plateauing pattern of enhancement (not shown). C, Through the inferior breasts: An irregularly marginated second mass is seen in the posterior medial right breast, against the implant margin. Kinetic analysis showed a plateauing pattern of enhancement (not shown).

FIGURE 2 Sagittal, enhanced, subtracted, T1-weighted gradient echo images of both breasts, 5 minutes after contrast administration (A to C). A, Through the right lateral breast: The mass seen in Figure 1B at 8 o’clock is depicted. Margins are irregular. B, Through the right medial breast: The mass seen in Figure 1C is shown. It has an oblong shape and irregular margins. C, Through the left central breast: The early enhancing mass at 12 o’clock with washout now blends into adjacent enhancing breast parenchyma.

Ultrasound correlates were sought. A 1-cm mass with increased vascularity and angular, irregular margins was found on the right at 8 o’clock, correlating with MRI (Figure 3). No ultrasound correlates for either of the two other sites were found. The right 8-o’clock suspicious mass underwent biopsy with ultrasound guidance, confirming infiltrating ductal carcinoma (IDC), estrogen receptor and progesterone receptor positive.

FIGURE 3 Ultrasound of the right breast at 8 o’clock shows a hypoechoic, solid, vascular, taller-than-wide, sonographically suspicious mass with angular margins, which corresponds to the MRI abnormality. Ultrasound-guided biopsy proved it to be an IDC.

An MRI-guided biopsy was performed on the left 12-o’clock enhancing abnormality. Benign results were obtained, with focal sclerosing adenosis and fibroadenomatous changes.

The patient decided on bilateral mastectomy, with implant removal and bilateral sentinel lymph node sampling. Pathology showed the sampled lymph nodes to be negative, with benign left breast findings and a residual 0.6-cm IDC in the right breast. The margins were negative. No correlate for the second site of concern in the right lower inner breast was found at pathology.

The patient was started on anastrozole (Arimidex) but discontinued it within a year because of intolerance.

TEACHING POINTS

If this patient had elected breast conservation therapy for her biopsy-proven right IDC, the question of what the second site of abnormal enhancement represented in the right lower inner quadrant at 5 o’clock would have had to have been addressed preoperatively. This would have been technically difficult. Its far posterior location in the medial breast and its position against the implant would have made MRI-guided biopsy difficult at best, assuming the lesion could even be reached from a medial approach, which limits how posterior a lesion can be accessed. An MRI-guided clip placement might have been possible, but a vacuum-assisted biopsy of a lesion against the implant margin runs the risk of rupturing the implant.

The imaging evaluation of palpable breast lumps in patients with implants utilizes the same tools as for women without augmentation. Mammography is the cornerstone, liberally supplemented with ultrasound. Breast MRI is also useful in selected patients and is not hampered either by the presence of breast implants or by increased density. In this case, the patient had had a recent, negative mammogram within a few months before (albeit before the palpable lump was identified). Ultrasound could have been utilized next. In this case, the patient’s plastic surgeon thought the palpable finding may have been related to implant rupture and sent the patient for breast MRI. If MRI showed the palpable lump to be related to extracapsular silicone, an enhanced evaluation may not have been necessary. However, because many facilities do not have the ability to monitor cases in real time, it can be more efficient to design MRI protocols to cover most eventualities. In this case, a “hybrid” protocol was utilized, featuring sequences for breast implant evaluation and enhanced, dynamic imaging for evaluation of the parenchyma. Our protocol for this is not as detailed or high resolution as the dedicated breast implant protocol, but suffices to exclude extravasated silicone as a cause of a palpable breast lump. It consists of a bilateral axial STIR sequence, a bilateral axial STIR sequence with water saturation (on which only silicone is bright), and an enhanced, subtracted, dynamic bilateral axial series for the parenchyma.

In this case, no correlate was found on MRI for the left palpable lump that prompted the MRI evaluation in the first place. Bilateral, suspicious, unsuspected abnormalities were identified, one of which proved to be a small breast cancer. This case points out the nonspecificity of appearance and enhancement characteristics of similar-appearing small MRI lesions. We have histologic diagnoses for two of these three lesions, with one a small IDC, another focal sclerosing adenosis and fibroadenomatous changes, and the other unknown.

CASE 18 Multifocal IDC in a patient with implants and dense breasts

An asymptomatic 71-year-old woman with bilateral subpectoral implants underwent screening mammography and subsequent breast ultrasound at an outside facility, which showed abnormalities suggesting multifocal right breast cancer (Figures 1, 2, 3, and 4). Although the patient had noted no problems, physician examination after the imaging abnormalities were identified found a conglomerate of grape-like masses measuring 2 cm in the right medial retroareolar area. Palpation-guided core needle biopsy of a mass at 3 o’clock identified well-differentiated infiltrating ductal carcinoma (IDC). Because of the implants, breast density, and apparent multifocal nature of the patient’s disease, local staging was completed with breast MRI. This confirmed multifocal medial right breast cancer, but showed no evidence of disease elsewhere (Figure 5).

FIGURE 1 MLO (A) and CC (B) mammograms show heterogeneous increased breast density and bilateral subpectoral implants. Comparison for symmetry shows a mass or mass-like parenchymal focus in the right medial breast on the CC view (arrow).

FIGURE 2 MLO (A) and CC (B) mammographic views with implants displaced suggest asymmetrical nodularity and multiple ill-defined masses in the right posterior medial breast (arrows).

FIGURE 3 Spot compression in the CC projection with implant displacement suggests at least two masses with ill-defined margins.

FIGURE 4 Ultrasound of the right upper inner quadrant shows three separate hypoechoic solid masses with angular margins, strongly suggesting multifocal breast cancer. The larger masses are annotated 1 and 2, and the third lesion is in between.

FIGURE 5 Breast MRI (axial maximal intensity projection) confirms multifocal breast cancer, with adjacent intensely enhancing and irregularly marginated masses in the right medial breast. No suspicious abnormality was seen elsewhere in the right breast or on the left.

Surgical treatment was a right mastectomy, and pathology identified three separate IDC tumor masses, measuring 1.4 cm, 1.3 cm, and 0.7 cm. One of 20 lymph nodes showed metastatic disease.

TEACHING POINTS

This is a difficult-to-image patient by virtue of the presence of implants and breast density. Remarkably, in this case, mammography and ultrasound did a very comprehensive job of locally staging this patient. However, the confidence level that the patient’s disease is accurately staged is certainly increased by the use of breast MRI, which is particularly useful in patients who are difficult due to implants, breast density, and prior surgery, radiation, or both.

CASE 19 Large, locally advanced IDC in an implant patient

A 60-year-old woman with long-standing breast implants presented with a large palpable lump in the lower outer quadrant of the right breast, found on monthly breast self-examination. Mammography showed a spiculated mass at the level of the palpable lump on implant-displaced views (Figure 1). Ultrasound demonstrated a large (8 cm) vascular mass with angular and spiculated margins (Figure 2). Sonography of the axilla showed multiple enlarged, rounded, abnormal lymph nodes (Figure 3). Because of the implants, histologic sampling was accomplished with ultrasound guidance, and confirmed poorly differentiated infiltrating ductal carcinoma. Fine-needle aspiration of an axillary lymph node was performed with ultrasound guidance at the same time, and demonstrated malignant cells, consistent with metastatic disease. Breast MRI showed a large dominant tumor mass, with additional satellite lesions (Figures 4 and 5). No evidence of occult disease was seen in the contralateral breast. Because of the large size of the mass, thought to be T3N1, neoadjuvant chemotherapy was given. Staging workup, completed during neoadjuvant chemotherapy, included bone scan, chest, abdomen and pelvis CT scans, spine MRI, and positron emission tomography (PET) (Figure 6). These evaluations showed bone metastases. (See Case 1 in Chapter 8 for a discussion of the imaging manifestations of this patient’s bony metastatic disease.)

FIGURE 1 MLO (A) and CC (B) mammographic views show bilateral prepectoral implants. A radiopaque marker was placed at the site of a palpable lump identified by the patient in the right breast. No definite correlate is seen, although some increased tissue density can be seen on the side of concern. C, CC implant displaced view shows a dominant right breast mass, at the level of the palpable lump identified by the radiopaque marker. D, On spot compression of the palpable lump, with the implant displaced, the spiculated margins of the mass are seen well.

FIGURE 2 Ultrasound of the palpable abnormality shows a large suspicious mass with irregular, angular, and spiculated margins.

FIGURE 3 Ultrasound of the axilla showed multiple abnormal axillary lymph nodes. One illustrated here is in profile. Although the fatty hilus is preserved, the cortical mantle is abnormally thick.

FIGURE 4 Maximal intensity projection of the volumetric data set from minute 1 of the enhanced, subtracted, dynamic acquisition provides an overview of both breasts. In the right breast, an intensely enhancing, dominant, spiculated mass fills the lateral breast. An additional round mass is noted behind the nipple. Right breast vessels are asymmetrically enlarged. The left breast shows only tiny, faint, diffuse stippled foci of enhancement. No pathologic patterns of enhancement were seen in the asymptomatic left side.

FIGURE 5 A, A slice from early in the dynamic enhanced series through the lower outer quadrant palpable abnormality shows a spiculated, dominant, intensely rim-enhancing mass extending to the margin of the breast implant. B, A corresponding T2-weighted axial image shows a marker at the level of the palpable lump, with the hypointense spiculated mass immediately subjacent. Most breast cancers (97% has previously been reported) are hypointense on T2-weighted MRI. C, A more superior section, through the nipples, shows three separate additional tumor nodules, including one in the retroareolar region. D, A sagittal, fat-saturated, enhanced T1-weighted MRI (unsubtracted) through the dominant mass shows clear extension to the implant surface and the nipple.

FIGURE 6 Sagittal (A) and axial (B) PET images show multifocal hypermetabolism in the right lateral breast, corresponding to the MRI findings. The axial section also shows a hypermetabolic focus in a lower thoracic vertebral body, one of several PET findings of bony metastases.

After completion of three cycles of neoadjuvant chemotherapy, the mass and adenopathy decreased. Three months after diagnosis, the patient underwent bilateral mastectomies, right axillary dissection, left sentinel lymph node sampling, and removal of the breast implants. The right mastectomy specimen contained a 3.5-cm invasive ductal carcinoma, with multiple satellite nodules. Nipple involvement was confirmed. The margins were clear. Six of 16 axillary lymph nodes displayed metastases. Left sentinel node sampling was negative.

The preoperative staging workup strongly suggested metastatic disease to bone. A sclerotic T11 vertebral body lesion was initially sampled 2 weeks after the patient’s breast surgery, and did not confirm metastatic disease. The needle biopsy was repeated 2 months later, and confirmed metastasis. A nearly concurrent repeat PET/CT for restaging showed normalization.

After completion of eight cycles of docetaxel (Taxotere), the patient was started on anastrozole (Arimidex) for her estrogen receptor–positive disease, as well as zoledronic acid (Zometa). She has been essentially asymptomatic on this therapy, with stable imaging studies for 2.5 years since the diagnosis of stage IV breast cancer metastatic to bone.

TEACHING POINT

This sizable tumor was initially thought to be a locally advanced breast cancer. Bone metastases, identified after beginning neoadjuvant chemotherapy, while systemic staging studies were being completed, indicate that the true stage is stage IV.