Breast Imaging: A Core Review (28 page)

7
 
Answer A.
 Sonographically, lymph nodes resemble kidneys. They are elliptical in shape with a hypoechoic cortex and an echogenic fatty hilum. On color or power Doppler, a feeding artery entering the hilum can be seen. The outer cortex should be smooth, without eccentric thickening. The appearance of the lymph node in this image is benign. A palpable lymph node, which is benign in appearance by ultrasound, does not require additional workup or biopsy.

Reference: Stavros AT.
Breast Ultrasound
. Philadelphia, PA: Lippincott Williams & Wilkins; 2004: 838–845, 855–870.

8
 
Answer C.
 On initial review of the images, the pleomorphic microcalcifications near the lumpectomy bed are the most obvious finding. These were new compared to the prior study, and images of the prior study were not provided. However, on more careful inspection, there is a focal asymmetry associated with the calcifications, making the findings even more concerning for malignancy. The findings are concerning for malignancy; therefore, an annual screening mammogram, annual diagnostic mammogram, and 6-month follow-up are inappropriate. MRI may be beneficial after the biopsy is performed if there is a concern for multicentric disease. Of the answer choices provided, stereotactic core biopsy of the calcifications is the most appropriate answer.

References: Kopans D.
Breast Imaging
. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007:967–969.
Stavros AT.
Breast Ultrasound
. Philadelphia, PA: Lippincott Williams & Wilkins; 2004:600–602, 609, 838–845.

9
 
Answer D.
 The calcifications demonstrated on the magnification views are pleomorphic in shape, meaning they vary in size and shape but are typically <0.5 mm in diameter. They are linear in distribution, meaning they are arrayed in a line, which may have branch patterns. The other answer choices describe benign calcifications. By mammographic criteria, calcifications which are pleomorphic have a 25% to 41% chance of being malignant, while calcifications in linear distribution have a 68% chance of being malignant. These were biopsied and the pathology results yielded DCIS with invasive ductal carcinoma.

References: Berg WA, Birdwell RL, eds.
Diagnostic Imaging: Breast
. Salt Lake City, UT: Amirsys; 2008;IV:0–4.
Kopans D.
Breast Imaging
. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007:989.

10a
 
Answer C.
 Masses are described by both their shape and margins. Terms used to describe the shape of a mass included round, oval, lobular, and irregular (mneumonic: “ROLI”). Terms used to describe the margins of a mass include circumscribed, obscured, microlobulated, indistinct, and spiculated (mneumonic: “COMIS”). In this case, the best description of the shape would be irregular, meaning the shape cannot be characterized by any of the other descriptors. The best description of the margins would be spiculated, meaning there are thin lines radiating from the margin of the mass. An irregular mass with spiculated margins is a concerning finding and requires further workup. By mammographic criteria, a mass with spiculated margins has an 81% to 97% chance of being malignant.

References: Berg WA, Birdwell RL, eds.
Diagnostic Imaging: Breast
. Salt Lake City, UT: Amirsys; 2008;IV:0-2–IV:0-3.
Kopans D.
Breast Imaging
. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007:984–986.
Shah BA, Fundaro GM, Mandava S.
Breast Imaging Review: A Quick Guide to Essential Diagnoses
. 1st ed. New York, NY: Springer; 2010:233.

10b
 
Answer D.
 Masses are described on ultrasound by multiple descriptors, two of which are shape and margins. The ultrasound descriptors are somewhat different than the mammographic descriptors. The shape of a mass is described as oval, round, or irregular. The margin is described as either circumscribed or not circumscribed. Noncircumscribed masses are then further divided into indistinct, microlobulated, angular, and spiculated. In this case, the best description of this mass would be an irregular shape with spiculated margins. This is a suspicious finding and requires biopsy. By ultrasound criteria, masses with an irregular margin have a 62% chance of being malignant while masses with spiculated margins have an 86% chance of being malignant. This underwent biopsy that yielded invasive lobular carcinoma.

Reference: Berg WA, Birdwell RL, eds.
Diagnostic Imaging: Breast
. Salt Lake City, UT: Amirsys; 2008;IV:0-10–IV:0-11.

10c
 
Answer B.
 Elastography measures the stiffness of a lesion compared to the surrounding tissues. Cysts are typically less stiff than the surrounding tissue, while solid masses are typically more stiff than the surrounding tissue. On the image provided, the color image is the elastography image. The scale to the right of the image has the abbreviation SF at the top of the scale, meaning soft. The abbreviation HD at the bottom of the image means hard. The mass in question is blue on elastography, which corresponds to hard or stiff on the elastography scale. Therefore, this mass is more stiff than the surrounding breast tissue and represents a solid mass requiring biopsy.

References: Burnside ES, Hall TJ, Sommer AM, et al. Differentiating benign from malignant solid breast masses with US strain imaging.
Radiology
2007;245:401–410.
Regner DM, Hesley GK, Hangiandreou NJ, et al. Breast lesions: Evaluation with US strain imagingclinical experience of multiple observers.
Radiology
2006;238:425–437.

11a
 
Answer B.

11b
 
Answer A.
 Fat necrosis can have a variety of appearances on breast MRI. The most common is a fat-containing cyst, which may or may not have a fat-fluid level within it. There is usually thin or thick rim enhancement, but this can also be absent. Enhancement can sometimes be seen for many years following surgery and can demonstrate persistent, plateau, or washout kinetics. Overall, an internal signal characteristic consistent with fat is key to diagnosis. Unenhanced T1 fat-saturated images can thus be very helpful. Fat necrosis can also present as a spiculated mass on MRI, mimicking new or recurrent malignancy when the macroscopic fat content is low. In these situations, biopsy may be necessary for diagnosis. On mammogram, fat necrosis can present as calcifications, usually curvilinear or eggshell but can mimic linear pleomorphic calcifications early in development. Fat necrosis can also present on mammography as lipid cysts, focal asymmetries, and spiculated masses.

References: Daly CP, Jaeger B, Sill D. Variable appearances of fat necrosis on breast MRI.
AJR Am J Roentgenol
2008;191(5):1374–1380.
Taboada JL, Stephens TW, Krishnamurthy S, et al. The many faces of fat necrosis in the breast.
AJR Am J Roentgenol
2009;192(3):815–825.

12
 
Answer D.
 Although this patient is quite young, this mass was indeed invasive ductal carcinoma. Breast cancer is uncommon in women in their 20s but can occur, with an annual risk of developing breast cancer of ~1/20,000 (as compared to 1/667 and 1/370 for women in their 40s and 50s, respectively). Breast cancer is one of the more common malignancies diagnosed during pregnancy. Although abscess would be reasonable to consider in a woman of this age, there is no clinical history of fever or breast erythema. In addition, although abscesses may have peripheral rim enhancement due to inflammation, internal flow, such as was seen in this case, should not be present. This mass was an invasive ductal carcinoma. Pregnancy should not prevent or delay workup of a suspicious mass. Excisional and core biopsies under local anesthesia are safe to perform during pregnancy.

References: Kopans D.
Breast Imaging
. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:89, 579–603.
Litton JK, Theriault RL, Gonzalez-Angulo AM. Breast cancer diagnosis during pregnancy.
Womens Health
2009;5(3):243–249.
Trop I, Dugas A, David J, et al. Breast abscesses: Evidence-based algorithms for diagnosis, management, and follow-up.
Radiographics
2011;31:1683–1699.

13
 
Answer C.
 The relevant finding on these images is the unilateral axillary adenopathy on the left MLO image. The differential diagnosis for unilateral adenopathy includes metastases, reactive adenopathy from inflammation or infection, or silicone from an implant rupture or leak. The differential diagnosis for bilateral axillary adenopathy includes HIV, lymphoproliferative disorders such as lymphoma or leukemia, rheumatoid arthritis and other collagen vascular diseases, and tuberculosis or sarcoidosis. This lymph node was biopsied and was consistent with metastases from ovarian carcinoma. The ovarian malignancy was known prior to the mammogram and was the reason this diagnostic mammogram was performed.

Reference: Berg WA, Birdwell RL, eds.
Diagnostic Imaging: Breast
. Salt Lake City, UT: Amirsys; 2008;IV:3–31.

14a
 
Answer C.

14b
 
Answer D.
 On the axial T1-weighted image, we can see the pectoral muscle clearly, indicating that this is a prepectoral implant. The second image is a water-saturated image, but the implant still has high signal, indicating that this is a silicone implant. The keyhole sign is present, consistent with intracapsular rupture. In addition, silicone is noted outside the implant capsule posterior, indicative of extracapsular rupture as well.

References: Berg WA, Caskey CI, Hamper UM, et al. Diagnosing breast implant rupture with MR imaging, ultrasound and mammography.
Radiographics
1993;13:1323–1336.
Liberman L, Morris E.
Breast MRI Diagnosis and Intervention
. 1st ed. New York, NY: Springer; 2005:245–252.
Yang N, Muradali D. The augmented breast: A pictorial review of the abnormal and the unusual.
AJR Am J Roentgenol
2011;196:W451–W460.

15
 
Answer D.
 Infiltrating lobular carcinoma is rare in males because the male breast lacks lobules. Exceptions would include males with exogenous estrogen stimulation, such as transsexuals on high dose estrogen therapy. It can also be seen in males treated with diethylstilbestrol (DES) for prostate cancer. Males with breast cancer typically have a worse prognosis due to a later stage at the time of diagnosis. Approximately 35% to 50% of male breast cancer is associated with DCIS. Approximately 50% have axillary adenopathy at the time of diagnosis.

Reference: Berg WA, Birdwell RL, eds.
Diagnostic Imaging: Breast
. Salt Lake City, UT: Amirsys; 2008;IV:5-54–IV:5-57.

16
 
Answer A.
 By convention, rolled CC views are performed with the superior half of the breast rolled medial (CCRM) and lateral (CCRL) prior to convention. These are performed when a lesion is seen on the CC view but not the MLO view and are useful to determine if a lesion is real and to locate in the sagittal plane.

Reference: de Paredes ES. Atlas of Mammography (electronic resource). 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007:37.

17
 
Answer A.
 The classic appearance of an extracapsular silicone rupture on ultrasound is the snowstorm appearance, in which the extracapsular silicone creates dirty shadowing. The extracapsular silicone can form silicone granulomas, which may present as palpable masses. The presence of extracapsular silicone does imply that there is a simultaneous or preexisting intracapsular rupture, though this may not be visualized by ultrasound. On this single image, the extracapsular silicone is visualized by the dirty shadowing; however, the intracapsular rupture is not visualized.

References: Berg WA, Birdwell RL, eds.
Diagnostic Imaging: Breast
. Salt Lake City, UT: Amirsys; 2008;IV:4-28–IV:4-31.
Stavros AT.
Breast Ultrasound. Philadelphia
, PA: Lippincott Williams & Wilkins; 2004:838–845, 240–243.

18
 
Answer B.
 A lateral-medial (LM) view would be preferred because the calcifications would be closer to the image receptor and this view will assist in localizing the calcifications. The cleavage view provides better visualization of the medial and posterior breast tissue but would not assist in localization of the finding. Spot compression view, if magnified, would provide information as to the morphology of calcifications but would not improve in providing information of the localization of the calcifications.