CASE 2 Multiple papillomas

A 69-year-old woman with a right breast nipple discharge underwent MRI evaluation. The MRI showed multiple enhancing masses in the superior right breast that were oriented in a ductal pattern (figure 1 and figure 2). Correlation with the patient’s mammogram revealed that the masses seen on MRI corresponded to multiple masses in the superior right breast on mammography (Figure 3). The masses had slowly increased in size over several years. The appearance on ultrasound suggested that these were intraductal masses (Figure 4). Needle localization and excisional biopsy were performed (figure 5 and figure 6). Pathology revealed multiple benign papillomas.

FIGURE 1 Postcontrast, subtracted, axial MRI demonstrates multiple, small, enhancing masses in the superior central right breast (arrows). The masses are aligned in a ductal orientation.

FIGURE 2 Postcontrast, subtracted, axial MRI with kinetic color overlay. The more anterior mass demonstrates central washout kinetics as denoted by the red area (arrow).

FIGURE 3 Right breast mediolateral oblique (MLO) mammographic view demonstrates multiple masses in the superior right breast, corresponding to the lesions seen on MRI (arrows).

FIGURE 4 Ultrasound images of the superior right breast (A and B) demonstrate multiple solid masses (arrows) corresponding to the MRI and mammographic findings. Adjacent fluid-filled ducts (seen in B) suggest that the masses are intraductal.

FIGURE 5 Needle localization mammogram, Two hook wires are seen bracketing the targeted masses.

FIGURE 6 Specimen x-ray. The targeted masses are identified in the right breast surgical specimen (arrows).

TEACHING POINTS

This case illustrates that benign papillomas may exhibit malignant features on MRI. In this example, multiple masses are seen in a ductal orientation, mimicking DCIS. In addition, papillomas may display a suspicious washout kinetic pattern, concerning for invasive carcinoma. Because of the overlap in the imaging appearance of papillomas and carcinoma, biopsy is required to establish the diagnosis.

CASE 5 Multifocal breast abscesses

A 37-year-old woman developed two right palpa-ble breast masses, which were exquisitely tender. There was no erythema. Mammographic and sonographic evaluations were performed. Mammography showed a dense, ill-defined lower outer quadrant mass. Ultrasound showed two hypoechoic, similar-appearing masses with angular, irregular margins (Figure 1). Ultrasound-guided core needle biopsies of both masses returned diagnoses of acute mastitis, with acute neutrophilic infiltrate, edema, and focal chronic inflammation. There was no evidence of malignancy.

FIGURE 1 Ultrasound of the right lower outer quadrant (LOQ) shows two similar-appearing, hypoechoic, irregularly marginated masses, a few centimeters apart. Both show enhanced through-transmission.

TEACHING POINTS

Inflammatory processes can mimic neoplasms perfectly in their imaging features. The clinical history usually allows differentiation. These “masses” are actually complex fluid collections, or abscesses. Other than the enhanced through-transmission, which suggests a homogeneous or fluid consistency, the sonographic features are those of malignancy.

CASE 7 Lymphocytic mastitis

A 47-year-old healthy woman developed a left retroareolar tender mass and a palpable 2-cm lump. She was sent for ultrasound for a suspected cyst. Ultrasound showed increased vascularity in the para-areolar region, but no discrete mass. No mammographic abnormality or change was seen (Figure 1). The surgeon’s physical examination noted tender induration without a discrete mass of the upper areola, extending 1 to 2 cm beyond the areola. A core needle biopsy was obtained in the office, and a 1-week trial of antibiotics was given. The needle biopsy specimen showed acute and chronic inflammation. A mixed inflammatory infiltrate of neutrophils, plasma cells, and lymphocytes was noted. Improvement was noted on antibiotics, but the tenderness subsequently recurred and antibiotics were restarted, without complete resolution.

FIGURE 1 MLO mammograms show heterogeneous, increased parenchymal density. The left retroareolar region is asymmetrically increased in density.

Breast MRI was obtained to better define the extent of the process (Figures 2, 3, 4, 5, 6, and 7). Intense mass-like enhancement of the medial left breast skin and retroareolar region was found, surrounding a fluid collection. Excisional biopsy removed a region of apparent granulation tissue and surrounding induration. The specimen showed chronically inflamed granulation tissue with adjacent fibrosis. Varying degrees of periductal, perilobular, and perivascular lymphocytic inflammation were noted, consistent with lymphocytic mastitis.

FIGURE 2 Axial T2-weighted breast MRI shows thickening of the left medial breast skin, extending to the nipple, which is retracted.

FIGURE 3 Axial short tau inversion recovery (STIR) image shows marked thickening and edema of the left medial breast skin. There is a diffuse increase in edema of the central retroareolar left breast compared with the right. A small cyst is seen on the left posteriorly.

FIGURE 4 Maximal intensity projection view of both breasts from enhanced, subtracted dynamic series shows a superficial, intensely enhancing, mass-like process involving the left medial breast.

FIGURE 5 Enhanced, subtracted view from the dynamic series shows intense, mass-like enhancement of the thickened left medial breast skin and retroareolar region. A fluid collection is outlined by the enhancing tissue.

FIGURE 6 Sagittal subtracted view of the left retroareolar level shows an intensely enhancing, poorly marginated mass. Periductal enhancement is seen.

FIGURE 7 More medial sagittal, subtracted view shows the confluent skin and subjacent enhancement, surrounding a fluid collection.

TEACHING POINTS

Inflammatory processes can mimic the imaging features of breast cancers. Compare the MRI findings in this case to those of Case 10 in Chapter 6, in which similar enhancement of the skin and nipple are due to recurrent breast cancer. Generally, the clinical features allow differentiation. This patient had a waxing and waning clinical course of recurrent tenderness, without fluctuation or drainage, which did not resolve with multiple courses of antibiotics. On initial imaging with ultrasound, no drainable fluid collection was seen. Breast MRI showed a fluid collection, which was small relative to the impressive, sheet-like confluent enhancement of the medial skin, subjacent breast parenchyma, and retroareolar region.

Lymphocytic mastitis has been reported in patients with diabetes and in autoimmune disease. This patient had no known risk factors.

CASE 8 New fat necrosis mass mimicking recurrence

A 73-year-old woman, previously treated for bilateral breast cancer with lumpectomies and radiation therapy, underwent routine mammographic surveillance. This was 11 years after treatment for right breast cancer and 3 years after treatment for the left, a T1N0, estrogen receptor–positive tumor. Mammography showed a new 8-mm mass with indistinct margins in the upper outer left breast (Figure 1). Sonography identified a corresponding abnormality, a 6-mm hypoechoic, shadowing mass with spiculated margins (Figure 2). Recurrent breast cancer was suspected, and the lesion was biopsied with ultrasound guidance (Figure 3).

FIGURE 1 MLO (A) and CC (B) mammograms show bilateral, central, postsurgical scarring. On the left, superomedial to the nipple, is seen an 8-mm mass, which was new compared with a mammogram 6 months before (arrows). Margins on spot compression are indistinct.

FIGURE 2 Ultrasound of the corresponding mass shows highly suspicious features. The mass is very hypoechoic and shadows, and the margin is spiculated.

FIGURE 3 Images obtained during a vacuum-assisted, 12-gauge core needle biopsy. The device is seen entering the field from the right and is positioned beneath the hypoechoic mass. Continuous sampling progresses upward through the mass, only a remnant of which was seen at the end of the procedure.

Pathology demonstrated benign fat necrosis with hyalinized sclerosis. Subsequent evaluations have shown postbiopsy changes and stable postoperative findings (Figures 4 and 5); no evidence of recurrence has been identified after 2 years of follow-up.

FIGURE 4 Follow-up ultrasound, 9 months later, of the site of the vacuum-assisted biopsy shows an echogenic clip surrounded by a hypoechoic rind of surrounding tissue reaction.

FIGURE 5 Image from the same ultrasound of the 4-year-old postoperative seroma in the same breast shows a complex fluid collection that is partly cystic and partly homogeneously echogenic.

TEACHING POINTS

Fat necrosis, the great mimic, strikes again! In this case, a discrete new mass developed 3 years after breast conservation treatment, with marginal indistinctness on mammography and fine spiculation on ultrasound. Because of its small size, it was biopsied with 12-gauge, vacuum-assisted technique, to ensure adequate sampling. The lesion was seen at the time of biopsy to be largely excised. This case reminds us that image-guided biopsies can induce changes that may be visualized on subsequent follow-up exams, especially if there is a hematoma complicating the original procedure. Biopsies themselves can induce fat necrosis. Clips are variable in their appearances and conspicuity on follow-up imaging. Postoperative fluid collections generally contract and regress over time, but not inevitably. Some collections, like this 4-year-old example, become organized and chronic.

CASE 9 Fibrosis mimicking recurrence in implant-reconstructed breast cancer patient

A 54-year-old woman, treated 10 years earlier for left breast infiltrating ductal carcinoma (IDC), developed a palpable periareolar mass. She had bilateral subpectoral implants placed in the past year. Her original tumor was T1cN1M0, and was treated with partial mastectomy, radiation therapy, six cycles of Cytoxan, methotrexate, 5-fluorouracil (CMF) chemotherapy, and 5 years of tamoxifen.

Ultrasound of the palpable periareolar mass showed a very hypoechoic, taller-than-wide, irregularly marginated mass (Figure 1). This was biopsied with ultrasound guidance, with 14-gauge core needle biopsy technique.

FIGURE 1 Ultrasound of the lateral retroareolar palpable lump shows suspicious sonographic features: extreme hypoechogenicity, taller-than-wide shape, irregular margins. The sonolucent implant is seen deep to the mass.

Pathology showed no carcinoma, with sclerosis, fibrosis, and foreign body giant cell reaction found.

TEACHING POINTS

This patient had implants placed in the prior year and had been treated with breast conservation for early-stage IDC 10 years before. The ultrasound appearance of this mass is highly suspicious and raised the specter of recurrent breast cancer in this patient. Fortunately, 14-gauge core needle biopsy confirmed a satisfactory alternate diagnosis. Fibrosis and foreign body giant cell reaction, presumably related to the patient’s implant surgery, produced a mass that mimics recurrent breast cancer. See Case 7 in Chapter 6 for a very similar-appearing ultrasound mass, which did represent a recurrence.

CASE 10 Lactational asymmetry on PET

A 38-year-old woman with a recent diagnosis of lymphoma underwent a staging positron emission tomography (PET) scan. The patient was breast-feeding at the time. The PET scan demonstrated the known lymphoma within the upper thorax (Figure 1). In addition, diffuse uptake was seen involving the right breast. A subsequently performed breast MRI showed diffuse non-mass-like enhancement of the right breast, as well as breast edema (Figures 2 and 3). Upon questioning, it became apparent that the patient was breast-feeding only from the right breast, owing to difficulty on the left. The imaging findings of unilateral benign lactational change correlated with the history. No further breast workup or follow-up was required.

FIGURE 1 Anterior projection whole-body PET image shows diffuse tracer uptake within the right breast (arrow). Also seen is upper thoracic uptake corresponding to the known lymphoma, as well as normal activity within the heart and bladder.

FIGURE 2 Postcontrast, subtracted, axial MRI of both breasts demonstrates diffuse non-mass-like enhancement of the right breast. No skin thickening or parenchymal distortion is seen.

FIGURE 3 Right (A) and left (B) breast fat saturated T2-weighted MRIs show diffuse edema of the right breast.

TEACHING POINTS

This case illustrates benign lactational breast changes, which should not be confused with a malignant process. In this example, although there is diffuse uptake on the PET scan and enhancement on the MRI, the imaging features are consistent with a benign process, given the absence of mass effect, parenchymal distortion, or secondary signs of malignancy, such as skin thickening or adenopathy. In addition to lactational changes, infection and trauma may mimic malignancy. This case also emphasizes the importance of clinical history in establishing such alternative diagnoses.