Mucocele-like Lesions: Radiologic-Pathologic Correlation.

Mucocele-like lesions (MLLs) of the breast are rare lesions described as dilated, mucin-filled cysts associated with rupture and extracellular mucin in the surrounding stroma. These lesions are of clinical concern because they can coexist with a spectrum of atypical and malignant findings, including atypical ductal hyperplasia, ductal carcinoma in situ, and invasive carcinoma including mucinous carcinoma. Imaging findings of MLLs are nonspecific and varied, although the most common initial finding is that of incidental coarse heterogeneous calcifications on mammography. Occasionally, an asymmetry or mass may be found with or without calcifications, and such MLLs have a higher rate of upgrade to malignancy at excision. Pathology findings are often descriptive given the small sample received from percutaneous biopsy, and the primary consideration is to report any associated atypia, including atypical ductal hyperplasia. There is consensus in the literature that MLLs with atypia on biopsy should undergo excision because of the average reported 17.5% (20/114) upgrade rate to malignancy. The upgrade rate for MLLs without atypia averages 4.1% (14/341). Therefore, imaging surveillance may be a reasonable alternative to excision for MLLs with no atypia on a case-by-case basis. We review MLL imaging findings, pathology findings, and clinical management and present 3 cases from our institution to add to the literature on these rare lesions.

A pictorial guide to artifacts on contrast mammography: How to avoid pitfalls and improve interpretation.

Contrast-enhanced mammography (CEM) is an increasingly accepted emerging imaging modality that demonstrates a similar sensitivity to MRI but has the advantage of being less time consuming and inexpensive. The use of CEM continues to expand as it is recognized and utilized as a valuable tool for diagnostic and potentially screening examinations. As with any radiologic examination, artifacts occur and knowledge of these is important for adequate image interpretation. The purpose of this paper is to provide a pictorial review the common artifacts encountered on CEM examinations and identify causes and potential resolutions.

Breast papillomas in the United States: single institution data on underrepresented minorities with a multi-institutional update on incidence.

PURPOSE: To assess the percentage of papillomas from all biopsies performed, comparing differences in patient age and race at a single institution. To assess trends in biopsied papillomas at institutions throughout the United States (US). METHODS: This is a HIPPA-compliant IRB-approved single-institution (Southern1) retrospective review to assess race and age of all-modality-biopsied non-malignant papillomas as a percentage of all biopsies (percentage papillomas calculated as papilloma biopsies/all biopsies) from January 2012 to December 2019. To assess national variation, several academic or large referral centers were contacted to provide data regarding papilloma percentages, biopsy modalities, and trends in case numbers. Trends were estimated using the method of analysis of variance (ANOVA). Comparisons of differences in trends were assessed. RESULTS: Southern1 institution demonstrated a significant association between race and percentage of papillomas (p < 0.0001). After adjustment for multiple comparisons with Bonferroni correction at 5% type I family error, the percentage of biopsied papillomas in Black and Asian patients remained significantly higher than in White patients (p < 0.0001 and p = 0.0032, respectively) using a Chi-square test. The regional variation in percentage of papillomas was found to be 3-9%. Southern1 institution showed a 7-year significant trend of increase in percentage of papillomas. Other institutions showed a decreasing trend (p < 0.05). CONCLUSION: Black and Asian women had significantly higher papilloma percentages compared to white patients in our single institution review. This institution also showed a statistically significant trend of increasing percentage papillomas from 2012 to 2019. Multi-institutional survey found regional variation in percentage papillomas, ranging from 3% to 9%.

Myofibroblastoma of the Breast: Diagnosis, Pathology, and Management.

Myofibroblastomas are rare benign spindle cell tumors that occur within both male and female breasts. They are composed of fibroblasts and myofibroblasts and are not associated with malignant potential. On mammographic and sonographic imaging, these tumors may present as oval circumscribed masses that overlap with the appearance of many benign entities, including fibroadenomas. Occasionally, the tumors may demonstrate interval growth or mimic imaging features of malignancy and require biopsy. Correct pathologic diagnosis is important because many morphologic variants exist, which complicates pathologic interpretation. The purpose of this article is to review the range of imaging manifestations and histopathological findings and to discuss current management.

Breast MRI during Neoadjuvant Chemotherapy: Lack of Background Parenchymal Enhancement Suppression and Inferior Treatment Response.

Background Suppression of background parenchymal enhancement (BPE) is commonly observed after neoadjuvant chemotherapy (NAC) at contrast-enhanced breast MRI. It was hypothesized that nonsuppressed BPE may be associated with inferior response to NAC. Purpose To investigate the relationship between lack of BPE suppression and pathologic response. Materials and Methods A retrospective review was performed for women with menopausal status data who were treated for breast cancer by one of 10 drug arms (standard NAC with or without experimental agents) between May 2010 and November 2016 in the Investigation of Serial Studies to Predict Your Therapeutic Response with Imaging and Molecular Analysis 2, or I-SPY 2 TRIAL (NCT01042379). Patients underwent MRI at four points: before treatment (T0), early treatment (T1), interregimen (T2), and before surgery (T3). BPE was quantitatively measured by using automated fibroglandular tissue segmentation. To test the hypothesis effectively, a subset of examinations with BPE with high-quality segmentation was selected. BPE change from T0 was defined as suppressed or nonsuppressed for each point. The Fisher exact test and the Z tests of proportions with Yates continuity correction were used to examine the relationship between BPE suppression and pathologic complete response (pCR) in hormone receptor (HR)-positive and HR-negative cohorts. Results A total of 3528 MRI scans from 882 patients (mean age, 48 years ± 10 [standard deviation]) were reviewed and the subset of patients with high-quality BPE segmentation was determined (T1, 433 patients; T2, 396 patients; T3, 380 patients). In the HR-positive cohort, an association between lack of BPE suppression and lower pCR rate was detected at T2 (nonsuppressed vs suppressed, 11.8% [six of 51] vs 28.9% [50 of 173]; difference, 17.1% [95% CI: 4.7, 29.5]; P = .02) and T3 (nonsuppressed vs suppressed, 5.3% [two of 38] vs 27.4% [48 of 175]; difference, 22.2% [95% CI: 10.9, 33.5]; P = .003). In the HR-negative cohort, patients with nonsuppressed BPE had lower estimated pCR rate at all points, but the P values for the association were all greater than .05. Conclusions In hormone receptor-positive breast cancer, lack of background parenchymal enhancement suppression may indicate inferior treatment response. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Philpotts in this issue.

A Randomized Phase IIb Study of Low-dose Tamoxifen in Chest-irradiated Cancer Survivors at Risk for Breast Cancer.

PURPOSE: Low-dose tamoxifen reduces breast cancer risk, but remains untested in chest-irradiated cancer survivors-a population with breast cancer risk comparable with BRCA mutation carriers. We hypothesized that low-dose tamoxifen would be safe and efficacious in reducing radiation-related breast cancer risk. PATIENTS AND METHODS: We conducted an investigator-initiated, randomized, phase IIb, double-blinded, placebo-controlled trial (FDA IND107367) between 2010 and 2016 at 15 U.S. sites. Eligibility included ≥12 Gy of chest radiation by age 40 years and age at enrollment ≥25 years. Patients were randomized 1:1 to low-dose tamoxifen (5 mg/day) or identical placebo tablets for 2 years. The primary endpoint was mammographic dense area at baseline, 1 and 2 years. IGF-1 plays a role in breast carcinogenesis; circulating IGF-1 and IGF-BP3 levels at baseline, 1 and 2 years served as secondary endpoints. RESULTS: Seventy-two participants (low-dose tamoxifen: n = 34, placebo: n = 38) enrolled at a median age of 43.8 years (35-49) were evaluable. They had received chest radiation at a median dose of 30.3 Gy. Compared with the placebo arm, the low-dose tamoxifen arm participants had significantly lower mammographic dense area (P = 0.02) and IGF1 levels (P < 0.0001), and higher IGFBP-3 levels (P = 0.02). There was no difference in toxicity biomarkers (serum bone-specific alkaline phosphatase, lipids, and antithrombin III; urine N-telopeptide cross-links) between the treatment arms. We did not identify any grade 3-4 adverse events related to low-dose tamoxifen. CONCLUSIONS: In this randomized trial in chest-irradiated cancer survivors, we find that low-dose tamoxifen is effective in reducing established biomarkers of breast cancer risk and could serve as a risk-reduction strategy.

Contrast mammography in clinical practice: Current uses and potential diagnostic dilemmas.

OBJECTIVE: This article will discuss the indications for Contrast Enhanced Spectral Mammography (CESM) with a focus on imaging interpretation including diagnostic dilemmas and pitfalls which may be encountered in practice. CONCLUSION: Understanding potential diagnostic dilemmas and pitfalls of CESM allows for enhanced interpretation. The clinical utilization of Contrast Enhanced Spectral Mammography (CESM) has increased significantly over the last few years. CESM demonstrates comparable sensitivity and accuracy to magnetic resonance imaging (MRI) for the evaluation of breast cancer but is less time consuming and less expensive. Because of this, CESM is now being used in lieu of MRI for many diagnostic indicators including the evaluation of abnormal mammographic findings, extent of disease, and response to neoadjuvant therapy. Additionally, ongoing research into the role of CESM in asymptomatic screening for breast cancer is evolving. As this technique becomes more popular, focusing on appropriate technique and interpretation is important. This article reviews the current and potential roles of CESM. It provides examples of CESM utilized for diagnostic indications while highlighting diagnostic dilemmas, pitfalls, and artifacts that may be encountered when interpreting CESM images.

Predicting breast cancer response to neoadjuvant treatment using multi-feature MRI: results from the I-SPY 2 TRIAL.

Dynamic contrast-enhanced (DCE) MRI provides both morphological and functional information regarding breast tumor response to neoadjuvant chemotherapy (NAC). The purpose of this retrospective study is to test if prediction models combining multiple MRI features outperform models with single features. Four features were quantitatively calculated in each MRI exam: functional tumor volume, longest diameter, sphericity, and contralateral background parenchymal enhancement. Logistic regression analysis was used to study the relationship between MRI variables and pathologic complete response (pCR). Predictive performance was estimated using the area under the receiver operating characteristic curve (AUC). The full cohort was stratified by hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status (positive or negative). A total of 384 patients (median age: 49 y/o) were included. Results showed analysis with combined features achieved higher AUCs than analysis with any feature alone. AUCs estimated for the combined versus highest AUCs among single features were 0.81 (95% confidence interval [CI]: 0.76, 0.86) versus 0.79 (95% CI: 0.73, 0.85) in the full cohort, 0.83 (95% CI: 0.77, 0.92) versus 0.73 (95% CI: 0.61, 0.84) in HR-positive/HER2-negative, 0.88 (95% CI: 0.79, 0.97) versus 0.78 (95% CI: 0.63, 0.89) in HR-positive/HER2-positive, 0.83 (95% CI not available) versus 0.75 (95% CI: 0.46, 0.81) in HR-negative/HER2-positive, and 0.82 (95% CI: 0.74, 0.91) versus 0.75 (95% CI: 0.64, 0.83) in triple negatives. Multi-feature MRI analysis improved pCR prediction over analysis of any individual feature that we examined. Additionally, the improvements in prediction were more notable when analysis was conducted according to cancer subtype.

Meniscal pathology in children: differences and similarities with the adult meniscus.

The normal meniscus undergoes typical developmental changes during childhood, reaching a mature adult appearance by approximately 10 years of age. In addition to recognizing normal meniscal appearances in children, identifying abnormalities - such as tears and the different types of discoid meniscus and meniscal cysts, as well as the surgical implications of these abnormalities - is vital in pediatric imaging. The reported incidence of meniscal tears in adolescents and young adults has increased because of increased sports participation and more widespread use of MRI. This review discusses the normal appearance of the pediatric meniscus, meniscal abnormalities, associated injuries, and prognostic indicators for repair.