B3 Lesions: Radiological Assessment and Multi-Disciplinary Aspects

Imaging Characteristics of and Multidisciplinary Management Considerations for Atypical Ductal Hyperplasia and Flat Epithelial Atypia: Review of Current Literature

High-risk lesions of the breast are frequently encountered in percutaneous biopsy specimens. While benign, these lesions have historically undergone surgical excision due to their potential to be upgraded to malignancy. However, there is emerging evidence that a tailored management approach should be considered to reduce overtreatment of these lesions. Flat epithelial atypia (FEA) and atypical ductal hyperplasia (ADH) are two of the most commonly encountered high-risk lesions. FEA has been shown to have a relatively low rate of progression to malignancy, and some guidelines are now recommending observation over routine excision in select cases. Selective observation may be reasonable in cases where the target lesion is small and completely removed at biopsy and when there are no underlying risk factors, such as a history of breast cancer or genetic mutation or concurrent ADH. ADH has the highest potential upgrade rate to malignancy of all the high-risk lesions. Most society guidelines continue to recommend surgical excision of this lesion. More recently, some literature suggests that ADH lesions that appear completely removed at biopsy, involve limited foci (less than two or three) with no necrosis or significant atypia, manifest as a small group of mammographic calcifications, or demonstrate no enhancement at MRI may be reasonable for observation. Ultimately, management of all high-risk lesions must be based on a multidisciplinary approach that considers all patient, radiologic, clinical, and histopathologic factors. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

High-risk breast lesions: role of multi-parametric DCE-MRI in detection and histopathological upgrade prediction

Background

High-risk breast lesions represent 3–21% of all breast lesions and are non-obligate precursors of malignancy. Various studies have evaluated the value of DCE-MRI including DWI and ADC mapping in the detection of high-risk breast lesions, differentiating them from malignant lesions and predicting upgrade risk after surgical excision reducing misdiagnosis and overtreatment. This study is a retrospective review of all image-guided breast biopsy procedures performed in 2021 at our institution, identified 68 patients with histopathologically proven high-risk breast and available MRI examinations with no concurrent ipsilateral malignancy. Image analysis of MRI examinations included morphological criteria, enhancement pattern, dynamic curves, DWI and ADC mapping assessment. Since our knowledge of high-risk breast lesions is still growing, this study is important to evaluate the merits of DCE-MRI in the assessment of high-risk breast lesions, to allow optimization of treatment, better limit it to those women at risk, and avoid overtreatment in women at low risk.

Results

The mean ADC value of high-risk breast lesions was not significantly different from that of malignant breast lesions (p value = 0.015). Non-mass enhancement and type III enhancing curve proved to be significant indicators of high-risk breast lesions upgrade in surgical pathology. Cut-off average ADC value for differentiating upgraded high-risk lesions from non-upgraded high-risk lesions proved 1.24 mm2/sec with sensitivity and specificity of 94 & 100%, respectively.

Discussion

Management of high-risk breast lesions is important in the screening setting, as they are non-obligate precursors of malignancy, and also function as risk indicators. Frequency and upgrade rates of high-risk lesions detected by MRI provide a reference for clinical management. DCE-MRI has a high negative predictive value in predicting the upgrade risk of high-risk lesions. In this study, non-mass enhancement and type III curve were proven to be indicators of high-risk lesion upgrade. Limitations of the study included small number of patients and limited follow-up period.

Conclusions

The use of multi-parametric DCE-MRI including DWI and ADC mapping provides complementary information to detect high-risk breast lesions and predict their upgrade rate.

High-risk lesions of the breast: concurrent diagnostic tools and management recommendations

Breast lesions with uncertain malignant behavior, also known as high-risk or B3 lesions, are composed of a variety of pathologies with differing risks of associated malignancy. While open excision was previously preferred to manage all high-risk lesions, tailored management has been increasingly favored to reduce overtreatment and spare patients from unnecessary anxiety or high healthcare costs associated with surgical excision. The purpose of this work is to provide the reader with an accurate overview focused on the main high-risk lesions of the breast: atypical intraductal epithelial proliferation (atypical ductal hyperplasia), lobular neoplasia (including the subcategories lobular carcinoma in situ and atypical lobular hyperplasia), flat epithelial atypia, radial scar and papillary lesions, and phyllodes tumor. Beyond merely presenting the radiological aspects of these lesions and the recent literature, information about their potential upgrade rates is discussed in order to provide a useful guide for appropriate clinical management while avoiding the risks of unnecessary surgical intervention (overtreatment).

Lesions of uncertain malignant potential of the breast (B3) on vacuum-assisted biopsy for microcalcifications: Predictors of malignancy

PURPOSE

To investigate clinical, radiologic and pathologic features of B3 lesions diagnosed on VABB targeting microcalcifications, for identifying predictors of malignancy.

METHOD

This retrospective multi-centre study included consecutive VABBs performed over a 10-year period on suspicious microcalcifications not associated with other radiological signs diagnosed as B3 on histology from VABB, with outcomes ascertained by surgical excision. Clinical, demographic, radiological and histological (B3 subcategory) data were collected. For statistical analysis (univariate and binary logistic regression), the primary outcome variable was the upgrade rate to malignancy after surgery. Predictors of upgrade to malignancy were identified from clinical, demographic, radiological and pathological variables (including B3 subcategory).

RESULTS

Amongst 447 VABBs, there were 57(12.7 %) upgrades to malignancy at surgical histology (36 DCIS and 21 invasive cancer). At univariate analysis, variables significantly associated with increased risk of upgrade to malignancy were age>55 years (p = 0.01), lesion size>10 mm (p < 0.0001), BI-RADS 4b-c and 5 (p = 0.0001), and fine pleomorphic morphology (p = 0.002) of microcalcifications. Binary logistic regression confirmed as significant independent risk factors age, lesion size and BI-RADS category (p = 0.02, 0.02 and 0.0006 respectively). Amongst subcategories of B3 lesions, lobular neoplasia was significantly(p = 0.04) associated with upgrade, confirmed as an independent risk factor [p = 0.03, OR = 2.3(1.1-4.7)]. Flat epithelial atypia was significantly(p = 0.004) associated with reduced odds of upgrade, but binary logistic regression showed only borderline association [p = 0.052, OR = 0.4(0.2-1.01)].

CONCLUSIONS

Across B3 lesions diagnosed on histology from VABB of suspicious microcalcifications, older age, size>10 mm, BI-RADS category≥ 4b on imaging, and lobular neoplasia were risk factors for upgrade to malignancy. This information can be used to discuss patients' tailored management options.

Relative apparent diffusion coefficient (rADC) in breast lesions of uncertain malignant potential (B3 lesions) and pathologically proven breast carcinoma (B5 lesions) following breast biopsy

PURPOSE

To assess relative apparent diffusion coefficient (rADC) and ADC in B3 and B5 lesions in premenopausal female patients, added to standard morpho-dynamic breast contrast-enhanced MRI.

METHODS

104 patients with histologically confirmed B3 (N1 = 52) and matched B5 lesions (N2 = 52), were examined on MRI (1.5 T, full diagnostic protocol, diffusion weighted imaging - b50, b850) in a retrospective analysis following the IRB approval: Atypical ductal hyperplasia (ADH, n1 = 20), Flat epithelial atypia (FEA, n2 = 11), Classic lobular neoplasia (CLN, n3 = 8), Papillary lesion (PL, n4 = 6) and Phyllodes tumor (PT, n5 = 7). rADC and ADC were computed for each lesion. The two-tailed Mann-Whitney U test was used for comparison with B5 lesions.

RESULTS

Mean rADC value for B3 lesions, (N1 = 52): 0.81+/-0.08 mm2/s x 10-3 and B5 lesions, (N2 = 52): 0.58+/-0.07 mm2/s x 10-3 is statistically different (p < 0.00001). Mean rADC values [mm2/s x 10-3], per entity in B3 are: ADH, 0.82+/-0.06; FEA, 0.75+/-0.03; CLN, 0.73+/-0.03; PL, 0.94+/-0.02; PT 0.86+/-0.05.

CONCLUSIONS

Although morpho-dynamic features of borderline and malignant lesions may overlap, the initial results in this research, suggest the highly significant difference in both ADC and rADC between B3 and B5 lesions. Larger trials are needed to confirm the initial data.

Our Radiological Experience on B3 Lesions: Correlation Between Mammographic and MRI Findings With Histologic Definitive Result

INTRODUCTION

The purpose of this study was to evaluate mammographic and magnetic resonance imaging (MRI) features in B3 lesions.

PATIENTS AND METHODS

From 2011 to 2018, 139 patients with histologically proven B3 lesions who underwent mammography or/and MRI, were retrospectively reviewed. B3 lesions were classified in: atypical ductal hyperplasia (ADH), lobular neoplasia (LN), papillary lesion (PL), radial scar (RS), flat epithelial atypia (FEA), phyllodes tumor (PT), or mesenchymal lesion. Imaging features evaluated were: the presence of microcalcifications, mass and architectural distortions on mammograms and type of margins (circumscribed, irregular, spiculate), enhancement (mass-like, non-mass-like), size (≤ 15 mm, > 15 mm), and kinetics curves (I, II, III) on MRI. The definitive histologic results confirmed benign lesion or were upgraded to malignancy, and the positive predictive value was calculated.

RESULTS

Histologic classification of B3 lesions counted 45 (32.37%) ADH, 12 (8.63%) LN, 25 (17.99%) PL, 5 (3.61%) RS, 31 (22.31%) FEA, 20 (14.39%) PT, and 1 (0.70%) mesenchymal lesion. One hundred seven patients had mammography, and 38 had MRI. In 90 (65%) cases, the histologic diagnosis confirmed B3, in 15 (11%) cases, benign lesion, and in 34 (24%) cases, malignancies were found, with best positive predictive value for mesenchymal tumor (1), ADH (0.36), and FEA (0.4). Significant correlations comparing core needle biopsy groups and microcalcifications (P = .016) and presence of mass (P = .002) and comparing definitive histology with the presence of mass (P = .023), were found. Regarding MRI, the morphology correlated with core needle biopsy groups (P = .038); morphology (P = .024), dimension (P = .040), and kinetic curve (P = .005) correlated with malignancy.

CONCLUSIONS

The B3 category includes different entities, with various risk of malignancy; their heterogeneity is associated with specific mammographic and MRI features, although further confirmations are needed.

Review on current treatment options for lesions of uncertain malignant potential (B3 lesions) of the breast: do B3 papillary lesions need to be removed in any case by open surgery?

BACKGROUND

In breast tissue, pre-malignant lesions are classified as BIRADS 3. The treatment of this heterogeneous group varies with expertise and tools available.

MATERIALS AND METHODS

With the example of two case reports, the literature is reviewed on current treatment options for BIRADS 3 breast lesions.

RESULTS

About 7% of all B-type breast biopsies fall into the B3 category. Approximately 35% of these B3 lesions are due to FEA, 20% to PLs and another 20% to ADH. Due to improvement in diagnostics, the incidence is increasing, while their value as a predictive factor for malignancy has steadily been fallen.

CONCLUSION

Depending on the histology of the needle biopsy, a complete resection with vacuum-assisted biopsy may be a treatment alternative to open biopsy.

Analysis of Efficacy and Accuracy of 2 Vacuum-Assisted Breast Biopsy Devices: Mammotome and Elite

BACKGROUND

Ultrasound-guided vacuum-assisted breast biopsy (US-VABB) has recently replaced surgical biopsy as a result of its high diagnostic accuracy and low patient discomfort, and at present it relies mainly on 2 devices, Mammotome and, more recently, Mammotome Elite (Elite). Our purpose was to compare the efficacy of these 2 bioptical devices.

PATIENTS AND METHODS

We performed US-VABB on 195 patients with Mammotome 8G or 11G in 130 patients and Elite 13G in 65 patients. Of these 195 patients, 95 were submitted to surgery for lumpectomy or mastectomy in case of malignant lesions or of lesions of uncertain malignant potential (B5 and B3), while the remaining 100 were strictly monitored clinically and radiologically for 12 to 24 months.

RESULTS

Both the devices showed high absolute sensitivity (96.2% for Mammotome and 83.3% for Elite), complete sensitivity (98.1% for Mammotome and 90.0% for Elite), specificity (92.3% for Mammotome and 94.3% for Elite), and diagnostic accuracy (99.1% for Mammotome and 95% for Elite), thus fulfilling criteria suggested by the European guidelines. Total underestimation rate seemed to be higher in the Elite cohort (14.2%) than in the Mammotome cohort (3.4%) (P = .02). However, none of the patients with a benign diagnosis (B2) presented any event during the follow-up period.

CONCLUSION

US-VABB is an accurate method for sampling breast lesions. Our study did not show large, statistically significant differences in diagnostic accuracy between the Elite and Mammotome systems, except for a slight increase in diagnostic underestimation of benign pathologies when using the Elite.