Question 1

A. Correct! BI-RADS category 0. Each BI-RADS category is paired with an assessment and recommendation. There is a mass present in the upper inner quadrant of the right breast, and additional imaging is needed to evaluate this mass. Therefore, this is BI-RADS category 0—additional imaging is needed.

Other choices and discussion

B. BI-RADS category 1 assessment means that there are no abnormalities on the mammogram. It is “negative,” with a management recommendation of routine mammography screening.

C. BI-RADS category 2 assessment means that there is a benign finding (history of excisional biopsy, lumpectomy, bilateral benign masses, etc.), and there are no suspicious abnormalities. The management recommendation is the same as a BI-RADS category 1 assessment.

D. BI-RADS category 3 assessment means that the finding is probably benign (>0% but ≤ 2% likelihood of malignancy). The only BI-RADS categories permitted after a screening exam are 0, 1, and 2. A diagnostic workup needs to be completed before a BI-RADS category 3 can be given.

E. BI-RADS category 4 assessment represents a suspicious abnormality. This category can be rendered after diagnostic workup and should not be used as an assessment on screening mammogram.

Question 2

A. Correct! Annual screening mammography for women aged 45 to 54 years with the option of beginning annual screening between ages 40 and 44. Biennial screening mammography starting at age 55 with the option to continue annual screening. These are the most recent 2015 American Cancer Society recommendations. Women should continue screening as long as they have good overall health and a life expectancy of ≥ 10 years.

Other choices and discussion

B. Annual screening mammogram starting at age 40 is the American College of Radiology and Society of Breast Imaging’s recommendation.

C. There are no guidelines that currently recommend both mammography and whole breast screening ultrasound for the average-risk woman.

D. Biennial screening mammography for women aged 50 to 74 years with an individual decision to start screening prior to 50 years old is the 2016 recommendation from the United States Preventative Services Task Force. The task force also concludes that there is insufficient evidence to assess the balance of benefits and harm for women > 75 years old.

E. Screening breast magnetic resonance imaging is not recommended in women of average risk for breast cancer.

Question 3

C. Correct! Women who have a first-degree relative with breast cancer should begin screening mammography at an age 10 years earlier than the age of the affected relative at time of diagnosis, or between 25 and 30 years old, whichever is later. This is according to the American College of Radiology’s appropriateness criteria.

Other choices and discussion

A. High-risk women include women with a > 20% lifetime risk, BRCA gene mutation carrier, women who has a first-degree relative with a BRCA gene mutation but themselves are untested, history of chest irradiation between ages 10 and 30, and other genetic mutations that lead to an increased incidence of breast cancer such as Li-Fraumeni syndrome.

B. According to the American College of Radiology’s appropriateness criteria, women who have had chest irradiation between the ages of 10 and 30 should begin screening mammography 8 years after radiation therapy, starting the earliest at age 25.

D. Woman with “dense breasts” do have a small increased risk of developing breast cancer compared to those who do not. However, there is currently insufficient evidence for adjunctive screening with other modalities.

E. A diagnosis of atypia (atypical ductal hyperplasia, atypical lobular hyperplasia) by itself does not put a woman at high enough risk to warrant supplemental screening with a breast magnetic resonance imaging.

Question 1

C. Correct! Biopsy of this lesion will reveal “benign, normal glandular tissue.” This is radiologic-pathologic concordant. This is a hamartoma. On pathology, a hamartoma cannot be differentiated from normal breast tissue, since they are the same glandular elements. Therefore, core biopsy may not be helpful for making the definitive diagnosis of a hamartoma.

Other choices and discussion

A. There is an oval, fat-containing mass with circumscribed margins at the site of the palpable abnormality. Findings are characteristic for a hamartoma, and no additional imaging (including ultrasound) is needed. Hamartomas are masses within the breast composed of both glandular tissue and fat and are described as having a “breast within a breast” appearance.

B. On ultrasound, hamartomas can appear as oval, circumscribed masses with heterogeneous internal echotexture similar to normal breast tissue.

D. If the typical appearance of a hamartoma is present on a screening mammogram, no additional imaging is needed.

E. As hamartomas contain normal glandular elements, cancer can arise within a hamartoma. Thus, any suspicious finding (calcifications, suspicious mass, etc.) within a hamartoma should be worked up and biopsied to evaluate for malignancy.

Question 2

A. Correct! Most oval, circumscribed, fat-containing masses on routine screening mammography are benign and require no additional workup. Differential diagnosis of these benign entities includes lipoma, hamartoma, fat necrosis, galactocele, and lymph node.

Other choices and discussion

B. A painful, enlarging, fat-containing mass may need surgical excision, as this would be atypical for the presentation of a benign lipoma or hamartoma.

C. With the advanced technology of digital breast tomosynthesis, the ability to detect fat within masses has improved, and it is possible to visualize fat within a breast cancer. The cancer can engulf fat as it grows.

D. Mammography is currently the standard modality for the evaluation of fat within a mass originally seen on ultrasound. A bilateral breast magnetic resonance imaging is generally not used for problem solving mammographic- or ultrasounddetected lesions.

E. On ultrasound, lipomas are typically oval, circumscribed masses that range from slightly hypoechoic to hyperechoic relative to the surrounding fat. They are usually found superficially, but can appear within the deeper breast tissue.

Question 3

A–D. All of these choices are correct! Although rare, there are malignant, fat-containing lesions. These include primary liposarcoma of the breast, phyllodes tumors, and invasive cancers such as invasive ductal carcinoma and invasive lobular carcinoma. The belief is that tumors can incorporate fat within the breast as they grow.

Other choice and discussion

E. Radial scars are benign sclerosing lesions with a central fibroelastic core and radiating spiculations. In general, radial scars cause architectural distortion that is seen on mammography. Occasionally, they may centrally contain fat. A radial scar is viewed as a “high-risk lesion,” and surgical excision is recommended for core needle biopsy revealing this pathology.

Question 1

A. Correct! There is diffuse bilateral trabecular and skin thickening on the mammogram. Inflammatory breast cancer usually presents as unilateral breast enlargement with increased density, trabecular thickening, and skin thickening on imaging. In rare cases, the findings may be bilateral secondary to severe locally advanced disease. Axillary adenopathy is present in about 50% of cases of inflammatory breast cancer.

Other choices and discussion

B. The differential for bilateral trabecular and skin thickening include systemic causes of volume overload, such as congestive heart failure, hepatic failure, and renal failure. Of note, edema resulting from these etiologies may be asymmetric due to the patient preference of positioning when in the supine position.

C. Central venous obstruction (as in superior vena cava thrombosis) can cause bilateral edema, manifested by trabecular and skin thickening. Vascular causes of unilateral breast edema include subclavian or axillary vein thrombosis.

D. In this specific case, the woman had a history of corrected tetralogy of Fallot and current severe heart and liver failure.

Question 2

C. Correct! The differential with this clinical presentation is mastitis versus inflammatory breast cancer. The clinical history, mammography, and ultrasound are collectively useful in differentiating underlying malignancy from abscess. A trial of antibiotics should first be attempted, and if findings do not completely improve after adequate antibiotic therapy, a skin punch biopsy would be advised.

Other choices and discussion

A. Inflammatory breast cancer is a clinical diagnosis. However, there must be a pathologic diagnosis of cancer coupled with an appropriate clinical presentation to make the diagnosis.

B. Magnetic resonance imaging is not indicated prior to a trial of antibiotics or before a definitive diagnosis of inflammatory breast cancer is made.

D. If the clinical history and imaging findings are concerning for abscess, an abscess drainage should be performed, with fluid sent to microbiology for culture. If no fluid can be aspirated, or if there is concern for a malignant mass, a subsequent biopsy could be performed with samples sent in formalin.

Question 3

C. Correct! Positron emission tomography/computed tomography is beneficial in newly diagnosed inflammatory breast cancer to evaluate for distant metastasis. Bone is the most common site of distant metastasis.

Other choices and discussion

A. The clinical presentation of inflammatory breast cancer is usually that of rapidly progressive breast erythema, edema, and tenderness, developing over a period of weeks to a few months. There is a lack of response to a trial of antibiotics. A commonly seen clinical finding is peau d’orange, meaning “skin of an orange” in French, caused by dermal lymphatic obstruction from tumor emboli.

B. Locally advanced breast cancer is cancer that progresses and directly invades the skin. The timeline of symptoms is the key feature that differentiates inflammatory breast cancer from locally advanced breast cancer (the latter with a slower progression and longer onset of symptoms, without the erythema or edema).

D. Inflammatory breast cancer has a highly aggressive course, with a 5-year survival rate of 25 to 50%. It accounts for approximately 2 to 5% of all breast cancers. About 20 to 40% of patients present with distant metastasis at the time of diagnosis.

E. Neoadjuvant chemotherapy followed by mastectomy and radiation therapy is the standard of care for inflammatory breast cancer. Neoadjuvant chemotherapy can shrink the existing tumor burden, helping with both locoregional control and systemic disease.

Question 1

C. Correct! This is compatible with a galactocele, which is the most common benign breast mass in a lactating woman. These form as a result of duct dilation and inflammation. A fat-fluid level is considered pathognomonic for a galactocele; however, this may also be seen in fat necrosis.

Other choices and discussion

A. The initial imaging workup for a woman < 30 years old with a palpable abnormality should be a targeted ultrasound. Ultrasound is also the first-line imaging modality in the workup of a palpable breast mass for a pregnant or lactating patient. This is because of ultrasound’s lack of ionizing radiation and its high sensitivity for detecting cancer in this patient population. In cases where sonographic findings are equivocal for a galactocele, a mammogram can aid in the diagnosis. The mammographic images shown in this case are consistent with a galactocele. Therefore, no ultrasound is needed.

B. This is not a suspicious abnormality, and biopsy is not indicated. Mammogram reveals an oval mass with obscured margins and a fat-fluid level on the mediolateral view. These findings, in addition to the clinical context of lactation, are consistent with a galactocele.

D. Galactoceles are cysts that contain milk and often contain necrotic or inflammatory debris. Aspiration would result in milkycolored fluid (not foul-smelling, serosanguinous fluid).

E. Additional potential complications following breast biopsy of a lactating woman include a milk-duct fistula (which is extremely rare) and blood within the breast milk. These risks should be discussed prior to the procedure.

Question 2

C. Correct! The milk may increase breast density and obscure important findings. Thus, prior to mammography, lactating patients are asked to pump or nurse to decrease the volume of milk.

Other choices and discussion

A. The low levels of scatter radiation do not support delaying mammography during pregnancy, when clinically indicated.

B. Bilateral breast magnetic resonance imaging requires intravenous gadolinium-based contrast. These contrast agents are NOT recommended during pregnancy because of the possible harmful effects to the developing fetus. However, there is a negligible excretion of this contrast in breast milk (a rate of 0.0004% of the maternal dose), and breast MRI can be safely performed in the lactating patient.

D. Pregnancy-associated breast cancer most commonly presents as a painless lump. It may also present as a unilateral enlarging breast with skin thickening, focal pain, and suspicious nipple discharge.

E. Traditionally, it was thought that women with pregnancy-associated breast cancer had a worse prognosis than those who did not. This may be explained by a delay in diagnosis (with larger tumor size at presentation). However, compared to age- and stage-matched controls, there are actually similar survival rates between woman with pregnancy and non-pregnancy-related breast cancers.

Question 3

All are correct!

A. Pregnancy-associated breast cancer represents approximately 10% of all newly diagnosed breast cancer cases in women < 40 years old. The mean age at diagnosis is between 32 and 34 years. The most common histology is high-grade, estrogen and progesterone receptor negative, invasive ductal carcinoma.

B. Growth of fibroadenomas can occur during pregnancy, as these are hormone-sensitive masses.

C. Lactating adenomas are benign lesions thought to be a fibroadenoma variant, tubular adenoma, or lobular hyperplasia due to the physiologic changes of pregnancy. In general, these may regress after pregnancy.

D. Galactoceles are the most common benign lesions in lactating woman. They are cysts that contain milk and inflammatory debris.

E. Disruption of the nipple-areolar complex and milk stasis places lactating women at risk for infection. If abscess is suspected, a clinical exam and ultrasound are recommended as the best initial workup.

Question 1

A. Correct! A history of radiation therapy on the left. Susceptibility artifact from surgical clips is present in the posterolateral left breast in this patient with a history of left lumpectomy and radiation therapy. The enhancement on the right corresponds to normal background parenchymal enhancement (BPE). Radiation therapy is known to decrease the amount of BPE.

Other choices and discussion

B. Although inflammatory breast cancer can present as asymmetric trabecular thickening and enhancement, there is no evidence of breast enlargement or skin enhancement in this patient.

C. BPE is dependent on several factors, one of which is hormones. Although the presence of exogenous hormones can increase the BPE, this typically results in bilateral and symmetric variation.

D. Similar to the influence of exogenous hormones, timing of the menstrual cycle can affect the amount of BPE. However, this fluctuation would typically be symmetric. The ideal imaging time with the least amount of BPE is during the follicular phase of the cycle (days 7 to 15).

E. There are no studies to show that laterality of contrast injection affects the amount of enhancement in the breast.

Question 2

B. Correct! Current National Comprehensive Cancer Network practice guidelines recommend that a breast magnetic resonance imaging (MRI) can be considered to evaluate the extent of disease in a patient with newly diagnosed breast cancer.

C. Correct! In patients with mammographically occult breast cancer and biopsy-proven axillary metastatic adenocarcinoma, a bilateral breast MRI can discover the primary lesion in approximately 60 to 70% of cases.

E. Correct! Results from the American College of Radiology Imaging Network (ACRIN 6657) study showed that MRI findings are a stronger predictor of pathologic response from neoadjuvant chemotherapy and residual cancer burden than is the clinical assessment.

Other choices and discussion

A. The American Cancer Society currently recommends the use of screening breast MRI for patients with a > 20% lifetime risk of breast cancer. In a high-risk patient population, combined MRI and mammography have a higher sensitivity (92.7%) than combined ultrasound and mammography (52%).

D. Bilateral breast MRI can evaluate for silicone implant integrity. Saline implant complications are usually apparent on clinical exam, and the saline is reabsorbed within the body.

Question 3

A. Correct! The first postcontrast phase of the exam should be acquired within the first 2 minutes postinjection. Imaging after this time will result in missing the peak enhancement of the lesion.

Other choices and discussion

B. The time intensity curves are divided into two phases: the “initial phase,” with images acquired within the first 2 minutes after injection, and the “delayed phase,” with images acquired after the first 2 minutes or peak enhancement. In general, peak enhancement usually occurs after 2 to 3 minutes of injection.

C. Although the most suspicious type of kinetic enhancement is initial rapid enhancement with washout on delayed images, there are benign findings (e.g., lymph nodes) that have the same enhancement characteristics. Thus, morphologic characteristics should be examined before a biopsy recommendation is made.

D. Kinetics are useful in the evaluation of any lesion (focus, mass, non-mass enhancement). However, a benign kinetic enhancement profile should not dissuade further workup for a morphologically suspicious mass or non-mass enhancement.

E. The enhancement threshold for computer-aided analysis tools can be selected by the interpreting radiologist and is usually set between a 50 and 100% increase in signal intensity from baseline to the first postcontrast study. Absence of a morphologically suspicious finding to meet threshold kinetic features does not prove benignity.

Question 1

C. Correct! There is bilateral intracapsular rupture. There is a “linguine” sign on the right, which indicates complete collapse of the silicone implant shell, and both a “linguine” (medially) and “keyhole” or “teardrop” (posteriorly) sign on the left. The keyhole sign indicates silicone gel outside of the implant shell but still contained within the fibrous capsule.

Other choices and discussion

A. Radial folds are normal infoldings of the implant shell, and they may mimic intracapsular rupture when complex. However, in this case, there is discontinuity of the implant capsule bilaterally (with partial collapse of the right implant).

B. There is no evidence of extracapsular rupture (silicone within the surrounding breast tissue) or silicone within lymph nodes on this image.

C. There must be intracapsular rupture (defect in the silicone implant shell) for extracapsular rupture to be present (rent in the fibrous capsule surrounding the implant).

D. There is no evidence of extracapsular rupture.

Question 2

D. Correct! In a study evaluating the effect of breast augmentation on the accuracy of mammography and cancer characteristics, the sensitivity of screening mammography was lower in women who had breast augmentation than in those who did not. However, the prognostic factors (tumor stage, nodal status, and estrogen-receptor status) were similar.

Other choices and discussion

A. There is no evidence that shows a cause or effect relationship between silicone breast implants and the development of breast cancer.

B. With intracapsular rupture, the implant shell (or envelope) is defective. However, the fibrous capsule that the body creates and surrounds the implant with is still intact. Thus, if there is an intracapsular silicone implant rupture, magnetic resonance imaging is superior to mammography for detection.

C. Manufacturer recommendations approved by the U.S. Food and Drug Administration support magnetic resonance imaging as the first-line imaging modality in the evaluation of a silicone implant complication.

E. Silicone gel has a T2-signal intensity that is higher than fat but lower than water. Thus, to truly evaluate for silicone extravasation either surrounding the implant shell or into the breast, it is best to use a T2-weighted sequence that suppresses both fat and water.

Question 3

D. Correct! Radial folds can generally be traced back to the implant capsule, whereas folds from a collapsed rupture are separated from the capsule. Tracing the origin of radial folds to the inner surface of the implant capsule is the key to distinguishing complex radial folds from intracapsular rupture.

Other choices and discussion

A. Asymptomatic women with implants are advised to have an MRI to check for implant rupture 3 years after placement and every 2 years thereafter, although some authors believe this may be too frequent and suggest every 10 years for patients without a breast cancer history.

B. Intracapsular rupture can be staged based upon the extent of deflation, ranging from not collapsed to fully collapsed. Extracapsular rupture can occur during any of these stages.

C. The term herniation is used when the implant shell is extruded through the fibrous capsule that surrounds the implant. Implants with herniation may not necessarily have a rupture, but herniation does imply a focal weakening/defect in that area.

E. Both silicone granulomas and silicone within lymph nodes have lower signal intensity on T2 water-suppressed sequences than does pure silicone gel. This is due to tissue ingrowth and the ratio of lymph node to silicone within nodes, respectively.

Question 1

E. Correct! BI-RADS 2. The mammographic findings are classic for bilateral benign-appearing masses. Normal interval follow up is recommended.

Other choices and discussion

The imaging findings are most consistent with bilateral benign-appearing masses. There is no mammographic evidence of malignancy. No further imaging is required, short-term follow up imaging is not needed, and biopsy is not indicated.

Question 2

D. Correct! Overall, the bilateral benign-appearing masses should appear similar. A mass appearing distinctly different from the others warrants diagnostic workup.

Other choices and discussion

A. Diagnosis requires at least three masses, with at least one located in each breast.

B. A round or oval mass with circumscribed margins meets diagnostic criteria. A mass with indistinct margins warrants diagnostic workup.

C. A palpable lump requires dedicated diagnostic workup, even if there are bilateral benign-appearing masses.

E. There is no increased risk of malignancy.