High-Risk Lesions Detected by MRI-Guided Core Biopsy: Upgrade Rates at Surgical Excision and Implications for Management.

OBJECTIVE. The purpose of our study was to evaluate the upgrade rates of high-risk lesions (HRLs) diagnosed by MRI-guided core biopsy and to assess which clinical and imaging characteristics are predictive of upgrade to malignancy. MATERIALS AND METHODS. A retrospective review was performed of all women who presented to an academic breast radiology center for MRI-guided biopsy between January 1, 2015, and November 30, 2018. Histopathologic results from each biopsy were extracted. HRLs-that is, atypical ductal hyperplasia (ADH), lobular carcinoma in situ (LCIS), atypical lobular hyperplasia (ALH), radial scar, papilloma, flat epithelial atypia (FEA), benign vascular lesion (BVL), and mucocelelike lesion-were included for analysis. Clinical history, imaging characteristics, surgical outcome, and follow-up data were recorded. Radiologic-pathologic correlation was performed. RESULTS. Of 810 MRI-guided biopsies, 189 cases (23.3%) met the inclusion criteria for HRLs. Of the 189 HRLs, 30 cases were excluded for the following reasons: 15 cases were lost to follow-up, six cases were in patients who received neoadjuvant chemotherapy after biopsy, two lesions that were not excised had less than 2 years of imaging follow-up, and seven lesions had radiologic-pathologic discordance at retrospective review. Of the 159 HRLs in our study cohort, 13 (8.2%) were upgraded to carcinoma. Surgical upgrade rates were high for ADH (22.5%, 9/40) and FEA (33.3%, 1/3); moderate for LCIS (6.3%, 3/48); and low for ALH (0.0%, 0/11), radial scar (0.0%, 0/28), papilloma (0.0%, 0/26), and BVL (0.0%, 0/3). Of the upgraded lesions, 69.2% (9/13) were upgraded to ductal carcinoma in situ (DCIS) or well-differentiated carcinoma. ADH lesions were significantly more likely to be upgraded than non-ADH lesions (p = .005). CONCLUSION. ADH diagnosed by MRI-guided core biopsy warrants surgical excision. The other HRLs, however, may be candidates for imaging follow-up rather than excision, especially after meticulous radiologic-pathologic correlation.

Performance of 2D Synthetic Mammography Versus Digital Mammography in the Detection of Microcalcifications at Screening.

OBJECTIVE. The purpose of this study is to compare the performance of 2D synthetic mammography (SM) to that of full-field digital mammography (FFDM) in the detection of microcalcifications and to evaluate radiologists' preference between the two imaging modalities for assessing calcifications. MATERIALS AND METHODS. A fully crossed, mode-balanced, paired-case (n = 160), retrospective, multireader (n = 3) performance study was implemented to compare screening mammograms acquired with digital breast tomosynthesis and both FFDM and SM between 2015 and 2017. The study cohort included 70 patients with mammograms recalled for microcalcifications (35 with malignant findings and 35 with benign findings) and was supplemented with 90 patients with mammograms with negative findings. In separate sessions, readers interpreted SM or FFDM images by recording a BI-RADS assessment and the probability of malignancy. In a final session that included 70 mammograms with microcalcifications, readers recorded their subjective assessment of microcalcification conspicuity and diagnostic confidence. RESULTS. There was no difference in diagnostic accuracy as assessed by comparing the likelihood of malignancy based on the AUC of plotted ROCs, with AUCs of 91% (95% CI, 83-97%) and 88% (95% CI, 79-95%) observed for SM and FFDM, respectively (p = 0.392), and with noninferiority of SM compared with FFDM (p = 0.011). No significant difference was observed between SM and FFDM in terms of sensitivity (77% vs 73%, respectively; p = 0.366) or negative predictive value (84% vs 82%, respectively; p = 0.598). The specificity and positive predictive value of SM were lower than those of FFDM (91% vs 98%, respectively [p = 0.034], and 87% vs 96%, respectively [p = 0.034]). All readers found calcifications to be more conspicuous on SM (p < 0.0001); however, no significant difference in subjective diagnostic confidence was seen. CONCLUSION. SM is noninferior to FFDM in the detection of microcalcifications. Despite the increased conspicuity of microcalcifications on SM, the subjective diagnostic confidence in the two modalities is comparable.

Revisiting Nonmass Enhancement in Breast MRI: Analysis of Outcomes and Follow-Up Using the Updated BI-RADS Atlas.

OBJECTIVE: The purpose of this study is to assess the frequency of reclassification of nonmass enhancement (NME) as background parenchymal enhancement (BPE) and to determine positive predictive values (PPVs) of NME descriptors using the revised BI-RADS atlas. MATERIALS AND METHODS: A retrospective review of our institution's MRI database from January 1, 2009, through March 30, 2012, identified 6220 contrast-enhanced breast MRI examinations. All findings prospectively assessed as NME and rated as BI-RADS categories 3, 4, and 5 (n = 386) were rereviewed in consensus by two radiologists who were blinded to pathologic findings with the fifth edition of the BI-RADS lexicon. Findings considered as postsurgical, associated with known cancers, NME given a BI-RADS category 3 assessment before 2009, previously biopsied, and those reclassified as BPE, focus, or mass were excluded (n = 181). Medical records were reviewed for demographics and outcomes. RESULTS: Two hundred five women were included (mean age, 48.8 years; range, 21-84 years). Seventy-seven of 386 findings (20.0%) were reclassified as BPE, and patients with BPE were younger than those with NME (mean age, 43.9 years; range, 31-62 years) (p = 0.003). Pathology results for 144 of 205 (70.2%) patients included 52 malignant, 11 high-risk, and 81 benign lesions. The highest PPVs for distribution patterns were 34.5% (10/29) for segmental and 100.0% (3/3) for diffuse distribution. The highest PPVs for internal enhancement patterns were 36.7% (11/30) for clustered ring enhancement and 27.5% (11/40) for clumped enhancement. No difference for NME malignancy rate was noted according to BPE (10/52 [19.2%] marked or moderate; 42/153 [27.5%] mild or minimal, p = 0.24). Thirty-two percent (17/52) of malignant NMEs had high T2 signal. CONCLUSION: Careful assessment of findings as BPE versus NME can improve PPVs, particularly in younger women. Although clustered ring enhancement had one of the study's highest PPVs, this number falls below previously published rates. Reliance on T2 signal as a benign feature may be misleading, because one-third of malignancies had T2 signal.

Assessment and Management of Challenging BI-RADS Category 3 Mammographic Lesions.

Breast Imaging Reporting and Data System (BI-RADS) category 3 lesions are probably benign by definition and are recommended for short-interval follow-up after a diagnostic workup has been completed. Although the original lexicon-derived BI-RADS category 3 definition applied to lesions without prior imaging studies (when stability could not be determined), in clinical practice, many lesions with prior images may be assigned to BI-RADS category 3. Although the BI-RADS fifth edition specifically delineates lesions that are appropriate for categorization as probably benign, it also specifies that the interpreting radiologist may use his or her discretion and experience to justify a "watchful waiting" approach for lesions that do not meet established criteria. Examples of such lesions include evolving masses or calcifications suggestive of prior trauma and instances when stability cannot be ascertained because of image quality. Although interval change is an important feature of malignancy, many benign lesions also change over time; thus, use of prior imaging studies and ongoing imaging surveillance to demonstrate the evolution of a probably benign lesion is justified. Some examples of common pitfalls associated with inappropriate BI-RADS category 3 assessment include failure to use proper BI-RADS descriptors, failure to perform a complete diagnostic workup, and overreliance on negative ultrasonographic findings. When appropriately used, short-interval follow-up saves many patients from undergoing biopsy of benign lesions, without decreasing the rate of cancer detection. (©)RSNA, 2016.

Outcome of cesarean scar pregnancies diagnosed sonographically in the first trimester.

OBJECTIVES: The purpose of this study was to determine the outcome of cesarean scar pregnancies diagnosed during the first trimester. METHODS: We retrospectively identified all cesarean scar implantation pregnancies diagnosed by sonography before 14 weeks' gestation between 2000 and 2012 at our institution. We reviewed the patients' sonograms and medical records and recorded sonographic findings and pregnancy outcomes. RESULTS: Thirty-four cases met study entry criteria. Ten patients presented with no embryonic cardiac activity, of whom 7 underwent interventions, and 3 were expectantly managed. One of the former 7 and none of the latter 3 required hysterectomy for bleeding. Among the 24 patients with embryonic cardiac activity, 8 were managed expectantly: 5 (62.5%) ultimately delivered a live-born neonate, 3 (60.0%) of whom required hysterectomy due to placenta accreta; and 3 had fetal demise. Sixteen of the 24 underwent interventions, 2 opting for gravid hysterectomy (10 and 11 weeks' gestation, respectively) and 14 treated by a minimally invasive method: intrasac potassium chloride injection (3 cases); intrasac potassium chloride injection plus intramuscular methotrexate (4 cases); sonographically guided dilation and curettage (6 cases); and laparascopic resection (1 case). None of the latter 14 subsequently required hysterectomy. CONCLUSIONS: If a woman has a first-trimester diagnosis of a cesarean scar implantation pregnancy and embryonic cardiac activity is present, expectant management offers the possibility of delivering a live-born neonate (62.5% in our study) but carries a substantial likelihood of hysterectomy at delivery due to placenta accreta (37.5% in our study), whereas minimally invasive therapy that interrupts the pregnancy largely eliminates the need for hysterectomy.

Mucocele-like Lesion of the Breast Diagnosed on Core Biopsy.

CONTEXT.­: Mucocele-like lesion of the breast (MLL) is an uncommon entity, and recent studies show low rates of upgrade from core needle biopsy (CNB) to excision. OBJECTIVE.­: To evaluate features associated with upgrade of MLLs diagnosed on CNB. DESIGN.­: Seventy-eight MLLs diagnosed on CNB from 1998-2019 and subsequent excisions were reviewed. Histologic parameters evaluated included the presence of atypia, presence and morphology of calcifications, and morphologic variant (classic [C-MLL], duct ectasia-like [DEL-MLL], or cystic mastopathy-like [CML-MLL]). RESULTS.­: Overall, 45 MLLs lacked atypia and 33 were associated with atypia (atypical ductal hyperplasia, 32; atypical lobular hyperplasia, 1). Most were C-MLLs (61) with fewer DEL-MLLs (14) and CML-MLLs (3). Half showed both coarse and fine calcifications, with fewer showing only coarse or fine calcifications, and some showing none. Subsequent excision or clinical follow-up was available for 25 MLLs without atypia-of which 2 (8.0%) were upgraded to ductal carcinoma in situ (DCIS)-and 23 with atypia, of which 4 (17.4%) were upgraded to DCIS. No cases were upgraded to invasive carcinoma. All upgraded cases showed coarse calcifications on CNB, and all upgraded cases were associated with residual calcifications on post-CNB imaging. CONCLUSIONS.­: Most MLLs present as calcifications and nearly half are associated with atypia. Upgrade to DCIS is twice as frequent in MLLs with atypia versus those without. A predominance of coarse calcifications and the presence of residual targeted calcifications following core biopsy may be associated with higher upgrade rates.

Subareolar Tissue Biopsy Predicts Occult Nipple Involvement in Nipple-Sparing Mastectomies.

OBJECTIVES: Subareolar tissue is examined during nipple-sparing mastectomy (NSM) to minimize the risk of occult malignancy within the preserved nipple. A positive subareolar tissue biopsy typically warrants subsequent nipple excision. We study the factors associated with a positive subareolar tissue biopsy, the rate of residual malignancy in subsequent nipple excisions, and the value of subareolar tissue biopsy intraoperative frozen section (IOF). METHODS: We identified 1,026 consecutive NSMs with separately submitted subareolar tissue biopsies over a 5.5-year period. Clinicopathologic data were reviewed. We examined concordance rates between subareolar tissue biopsy and subsequent nipple excisions as well as IOF diagnosis and permanent control diagnosis. RESULTS: Among cases of therapeutic NSM, the rate of a positive subareolar tissue biopsy was 7.2%. Multifocal/multicentric disease (P = .0005), presence of lymphovascular invasion (P = .033), and nodal involvement (P = .006) were significantly associated with a positive subareolar tissue biopsy. Thirty-nine of 41 cases with positive subareolar biopsies underwent subsequent nipple excision, with 20 (51%) showing residual carcinoma. Among all IOF samples, 9 (3.3%) showed a discrepancy between the IOF and permanent diagnoses, mostly because of false-negatives. CONCLUSIONS: A positive subareolar tissue biopsy predicts residual carcinoma in the excised nipples in 51% of cases. IOF is accurate and reliable.

Systemic treatment in breast cancer: a primer for radiologists.

UNLABELLED: Cytotoxic chemotherapy, hormonal therapy and molecular targeted therapy are the three major classes of drugs used to treat breast cancer. Imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI), (18)F-FDG positron emission tomography (PET)/CT and bone scintigraphy each have a distinct role in monitoring response and detecting drug toxicities associated with these treatments. The purpose of this article is to elucidate the various systemic therapies used in breast cancer, with an emphasis on the role of imaging in assessing treatment response and detecting treatment-related toxicities. TEACHING POINTS: • Cytotoxic chemotherapy is often used in combination with HER2-targeted and endocrine therapies. • Endocrine and HER2-targeted therapies are recommended in hormone-receptor- and HER2-positive cases. • CT is the workhorse for assessment of treatment response in breast cancer metastases. • Alternate treatment response criteria can help in interpreting pseudoprogression in metastasis. • Unique toxicities are associated with cytotoxic chemotherapy and with endocrine and HER2-targeted therapies.