Majority of flat epithelial atypia diagnosed on biopsy do not require surgical excision

Retained Biopsy Site Markers After Breast Lesion Surgical Resection: Associations With Residual Malignancy

BACKGROUND. Biopsy site markers (BSMs) placed during image-guided core needle biopsy (CNB) are typically targeted for surgical excision, along with the breast imaging abnormality. Retained BSMs raise concern of incomplete resection of the breast abnormality. OBJECTIVE. The purpose of our study was to assess the frequency of residual malignancy in patients with retained BSMs identified on the initial mammography performed after breast lesion surgical excision. METHODS. This retrospective study included 30 patients (median age, 59 years) who underwent surgical resection between August 2015 and April 2022 of a borderline, high-risk, or malignant breast lesion after CNB and technically adequate preoperative image-guided localization, in whom the initial postoperative mammography report described a retained nonmigrated BSM. EMR data were extracted. The index pathology from CNB and initial surgical resection was classified as malignant or nonmalignant. The presence of residual malignancy after initial surgical resection required pathologic confirmation from subsequent tissue sampling; the absence of residual malignancy required 2 years of benign imaging follow-up. RESULTS. Thirteen specimen radiographs were interpreted intraoperatively by a surgeon with later radiologist interpretation, and 17 underwent real-time radiologist interpretation. Eighteen patients had malignant index pathology from the initially resected lesion. The frequency of residual malignancy on subsequent follow-up after initial surgical resection was higher in patients with malignant than nonmalignant index pathology (39% [7/18] vs 0% [0/12], respectively; p = .02). Among patients with malignant index pathology, the frequency of residual malignancy was higher in those without, than with, malignancy in the initial surgical specimen (80% [4/5] vs 23% [3/13]; p = .047). Also in these patients, the frequency of a positive interpretation of the initial postoperative mammography (BI-RADS category 4 or 6) was not significantly different between those with and without residual malignancy (57% [4/7] vs 55% [6/11]; p > .99). CONCLUSION. Patients with retained BSMs associated with malignant index lesions are at substantial risk of having residual malignancy. Initial postoperative mammography is not sufficient for excluding residual malignancy. CLINICAL IMPACT. Retained BSMs associated with index malignancy should be considered suspicious for residual malignancy. In this scenario, timely additional tissue sampling targeting the retained BSM is warranted, given the greater-than-2% chance of malignancy. Active surveillance is a reasonable management strategy in patients with retained BSMs from nonmalignant index lesions.

European guidelines for the diagnosis, treatment and follow-up of breast lesions with uncertain malignant potential (B3 lesions) developed jointly by EUSOMA, EUSOBI, ESP (BWG) and ESSO

INTRODUCTION

Breast lesions of uncertain malignant potential (B3) include atypical ductal and lobular hyperplasias, lobular carcinoma in situ, flat epithelial atypia, papillary lesions, radial scars and fibroepithelial lesions as well as other rare miscellaneous lesions. They are challenging to categorise histologically, requiring specialist training and multidisciplinary input. They may coexist with in situ or invasive breast cancer (BC) and increase the risk of subsequent BC development. Management should focus on adequate classification and management whilst avoiding overtreatment. The aim of these guidelines is to provide updated information regarding the diagnosis and management of B3 lesions, according to updated literature review evidence.

METHODS

These guidelines provide practical recommendations which can be applied in clinical practice which include recommendation grade and level of evidence. All sections were written according to an updated literature review and discussed at a consensus meeting. Critical appraisal by the expert writing committee adhered to the 23 items in the international Appraisal of Guidelines, Research and Evaluation (AGREE) tool.

RESULTS

Recommendations for further management after core-needle biopsy (CNB) or vacuum-assisted biopsy (VAB) diagnosis of a B3 lesion reported in this guideline, vary depending on the presence of atypia, size of lesion, sampling size, and patient preferences. After CNB or VAB, the option of vacuum-assisted excision or surgical excision should be evaluated by a multidisciplinary team and shared decision-making with the patient is crucial for personalizing further treatment. De-escalation of surgical intervention for B3 breast lesions is ongoing, and the inclusion of vacuum-assisted excision (VAE) will decrease the need for surgical intervention in further approaches. Communication with patients may be different according to histological diagnosis, presence or absence of atypia, or risk of upgrade due to discordant imaging. Written information resources to help patients understand these issues alongside with verbal communication is recommended. Lifestyle interventions have a significant impact on BC incidence so lifestyle interventions need to be suggested to women at increased BC risk as a result of a diagnosis of a B3 lesion.

CONCLUSIONS

These guidelines provide a state-of-the-art overview of the diagnosis, management and prognosis of B3 lesions in modern multidisciplinary breast practice.

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.

Are Columnar Cell Lesions the Earliest Non-Obligate Precursor in the Low-Grade Breast Neoplasia Pathway?

Columnar cell lesions (CCLs) of the breast comprise a spectrum of morphologic alterations of the terminal duct lobular unit involving variably dilated and enlarged acini lined by columnar epithelial cells. The World Health Organization currently classifies CCLs without atypia as columnar cell change (CCC) and columnar cell hyperplasia (CCH), whereas flat epithelial atypia (FEA) is a unifying term encompassing both CCC and CCH with cytologic atypia. CCLs have been increasingly recognized in stereotactic core needle biopsies (CNBs) performed for the assessment of calcifications. CCLs are believed to represent the earliest non-obligate precursor of low-grade invasive breast carcinomas as they share molecular alterations and often coexist with entities in the low-grade breast neoplasia pathway. Despite this association, however, the risk of progression of CCLs to invasive breast carcinoma appears low and may not exceed that of concurrent proliferative lesions. As the reported upgrade rates of pure CCL/FEA when identified as the most advanced high-risk lesion on CNB vary widely, the management of FEA diagnosed on CNB remains controversial. This review will include a historical overview of CCLs and will examine histologic diagnostic criteria, molecular alterations, prognosis and issues related to upgrade rates and clinical management.

Upgrade rate of percutaneously diagnosed pure flat epithelial atypia: systematic review and meta-analysis of 1,924 lesions

CONTEXT

Management remains controversial due to the risk of upgrade for malignancy from flat epithelial atypia (FEA). Data about the frequency and malignancy upgrade rates are scant. Namely, observational follow-up is advised by many studies in cases of pure FEA on core biopsy and in the absence of an additional surgical excision. For cases of pure FEA, the American College of Surgeons no longer recommends surgical excision but rather recommends observation with clinical and imaging follow-up.

OBJECTIVES

The aim of this study is to perform a systematic review and meta-analysis to calculate the pooled upgrade of pure FEA following core needle biopsies.

METHODS

A search of MEDLINE and Embase databases were conducted in December 2020. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. A fixed- or random-effects model was utilized. Heterogeneity among studies was estimated by utilizing the I2 statistic and considered high if the I2 was greater than 50%. The random-effects model with the DerSimonian and Laird method was utilized to calculate the pooled upgrade rate and its 95% confidence interval.

RESULTS

A total of 1924 pure FEA were analyzed among 59 included studies. The overall pooled upgrade rate to malignancy was 8.8%. The pooled upgrade rate for mammography only was 8.9%. The pooled upgrade rate for ultrasound was 14%. The pooled upgrade rate for mammography and ultrasound combined was 8.8%. The pooled upgrade rate for MRI-only cases was 27.3%.

CONCLUSIONS

Although the guidelines for the management of pure FEA are variable, our data support that pure FEA diagnosed at core needle biopsy should undergo surgical excision since the upgrade rate >2%.

Upgrade Rate of Pure Flat Epithelial Atypia Diagnosed at Core Needle Biopsy: A Systematic Review and Meta-Analysis

Purpose

To perform a systematic review and meta-analysis to calculate the pooled upgrade rate of pure flat epithelial atypia (FEA) diagnosed at core needle biopsy (CNB).

Materials and Methods

A PubMed and Embase database search was performed in December 2019. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Study quality and publication bias were assessed. The upgrade rate of pure FEA to cancer, invasive carcinoma, and ductal carcinoma in situ (DCIS), as well as the co-occurrence rate of atypical ductal hyperplasia (ADH), with 95% CIs were calculated. A random effect model was used to integrate the proportions and their corresponding 95% CI. Study heterogeneity was calculated using τ2 and I 2 .

Results

A total of 2482 cases of pure FEA across 42 studies (mean age range, 46-59 years) met inclusion criteria to be analyzed. Significant study heterogeneity was identified (τ2 = 0.001, I 2 = 67%). The pooled upgrade rates reported for pure FEA were 5% (95% CI: 3%, 6%) for breast cancer, 1% (95% CI: 0%, 2%) for invasive carcinoma, and 2% (95% CI: 1%, 3%) for DCIS. When more than 90% of calcifications were removed at CNB, the pooled upgrade rate was 0% (95% CI: 0%, 2%). The pooled co-occurrence rate of ADH at surgical excision was 17% (95% CI: 12%, 21%). Study quality was medium to high with a risk of publication bias (P < .01).

Conclusion

Pure FEA diagnosed at CNB should be surgically excised due to the pooled upgrade rate of 5% for breast cancer. If more than 90% of the targeted calcifications are removed by CNB for pure FEA, close imaging follow-up is recommended.Keywords: Biopsy/Needle Aspiration, Breast, MammographySupplemental material is available for this article.© RSNA, 2021.

Is Excisional Biopsy Needed for Pure FEA Diagnosed on a Core Biopsy?

BACKGROUND

The management of flat epithelial atypia (FEA) on core needle biopsy remains controversial. The upstaging rates after surgical excision are variable. In this study, we seek to determine the upstaging rate of FEA at our institution.

METHODS

Patients with a diagnosis of FEA were identified from the institution's pathology database from 2009 to 2018. Patients were included in the study if FEA alone, without atypia or cancer, was identified on core needle biopsy. Patient demographics, imaging, management, and pathology characteristics were obtained. Statistical analysis performed using IBM SPSS 26.0 (Armonk, NY, USA).

RESULTS

FEA was diagnosed on core needle biopsy in 235 patients from 2009 to December 2018. Forty-eight patients met the inclusion criteria. The majority of patients presented with calcifications on mammogram (n = 21, 64%) with the remainder as masses (n = 6, 18%) or architectural distortion (n = 6, 18%). Of those, 15 (31%) patients declined surgical excision, of which none developed cancer over a mean follow-up of 4.4 years. Of the 33 (69%) patients undergoing excisional biopsy, 17 (52%) confirmed FEA, 11 (33%) had benign findings, and 3 (9%) demonstrated atypical ductal hyperplasia on final pathology. One (3%) case revealed ductal carcinoma in situ (DCIS) and 1 (3%) was upgraded to invasive cancer for an overall upstaging rate of 4% (2/48). After a mean follow-up of 3.4 years, none of the excisional biopsy patients developed invasive breast cancer. Adjuvant therapy was used in the cases of DCIS and invasive cancer; however, chemoprevention with raloxifene or tamoxifen was not chosen by any of the remaining patients.

CONCLUSION

In our cohort, expectant management of FEA alone appears to be a safe option as our upstaging rate to DCIS or invasive cancer for FEA diagnosed on core biopsy was only 4%. Our study suggests that close follow-up is a safe and feasible option for pure FEA without a radiographic discordance found on core biopsy.

High-risk lesions diagnosed at MRI-guided vacuum-assisted breast biopsy: imaging characteristics, outcome of surgical excision or imaging follow-up

BACKGROUND

To evaluate imaging characteristics, outcome of surgical excision or imaging follow-up on high-risk lesions diagnosed at MRI-guided vacuum-assisted breast biopsy (MRI-VABB).

METHODS

We retrospectively reviewed 598 lesions undergoing 9-gauge MRI-VABB from January 2015 to April 2018 to identify high risk breast lesions. We collected patient demographics, breast MRI BI-RADS descriptors, histopathological diagnosis at MRI-VABB and surgical excision, frequency of upgrade to malignancy and imaging follow-up of high-risk lesions. The x² test and Fisher exact tests were performed for univariate analysis.

RESULTS

114 patients with 124/598 findings (20.7%) had high-risk lesions at MRI-VABB, including atypical ductal hyperplasia (ADH) (21/124, 16.9%), lobular neoplasia (40/124, 32.3%), radial scar/complex sclerosing lesion (RS/CSL) (13/124, 10.5%), papillary lesions (49/124, 39.5%), and flat epithelial atypia (FEA) (1/124, 0.8%). 84/124 (67.7%) high-risk lesions were excised. 19/84 (22.6%) were upgraded to malignancy (7 invasive cancer, 12 DCIS). The upgrade rate for ADH and lobular neoplasia was 7/18 (38.9%) and 9/31 (29.0%), respectively. The upgrade rate for RS/CSL was 1/10 (10%). Of the 25 papillary lesions excised, 2 (8%) demonstrated pathologic atypia and were upgraded to DCIS. The other 23 papillary lesions had no upgrade or atypia. Excised high-risk lesions showing upgrade varied from 0.4 to 6 cm in length (mean 1.6 cm). There was a non-significant trend (p = 0.054) between larger lesion and upgrade to malignancy; however, there were no other specific imaging features to predict malignancy upgrade.

CONCLUSIONS

There were no specific MRI imaging characteristics of high-risk lesions to predict malignancy upgrade. Therefore, surgical excision is recommended for high-risk lesions, especially ADH or lobular neoplasia.

Columnar cell lesions of the breast: a practical review for the pathologist

Background

Columnar cell lesions (CCLs) of the breast are characterized by the substitution of regular layer of cuboid epithelial by columnar cells covering the terminal duct lobular units (TDLUs). It also comprises a spectrum of lesions characterized by enlarged TDLUs with variably dilated acini lined by columnar epithelial cells, ranging from one or two layers of benign epithelium to stratified epithelium with atypia. With the increasing use of mammography screening scans in the last 30 years, columnar cell lesions (CCLs) have been diagnosed more frequently, often associated with microcalcifications and abnormal calcifications, requiring breast biopsies. This literature review presents the historical development of this entity description, with many terminologies, the CCLs categories, differential diagnoses, immunohistochemical profile and genetic alterations, reproducibility and clinical implications. In addition it discusses the significance of flat epithelial atypia (FEA), a CCL with low-grade cytological atypia.

Practical considerations

FEA are a frequent finding in breast biopsies and should be a warning sign for other possible entities within the lesion area. Since CCLs are an increasingly recognized entity in the diagnostic spectrum of breast proliferative lesions, proper training or tutorials are advisable for general pathologists in order to teach them how to identify CCLs with confidence. Intraductal proliferations with architectural complexities such as cribriform patterns, rigid cellular bridges, and true micropapillary pattern should not fall into the FEA category and are best classified as atypical ductal hyperplasia (ADH) or ductal carcinoma in situ (DCIS).

Conclusions

Among CCLs, FEA actually receives more attention due to atypia involved. FEA has been considered a non-obligate pre-neoplastic lesion and progression of these lesions to invasive cancer has been reported as increasingly low (2–7%). Therefore, controversy to the management of those lesions still remains and further intervention is restricted to cases with other premalignant lesions (ADH, DCIS) or in radiologic-pathologic disagreement.

Flat epithelial atypia: are we being too aggressive?

PURPOSE

The malignant upgrade rate of flat epithelial atypia (FEA) diagnosed on core needle biopsy varies between 0 and 30%. Excision versus observation with radiological follow-up for these lesions remains controversial. We hypothesize that the local rate of FEA is low and that close radiological surveillance is a reasonable treatment option for patients diagnosed with pure FEA on breast needle core needle biopsy.

METHODS

This study was a retrospective review of a prospectively collated provincial pathology database. Patients diagnosed with FEA alone on needle core biopsy between 2006 and 2016 were included in our analysis. Patients who had FEA present together with either in situ or invasive carcinoma within the same biopsy cores were excluded. Along with patient demographics, the size of the lesion on preoperative imaging, the method of extraction, and the presence of co-existing benign and malignant pathology on final excision biopsy were analyzed. An independent pathological review was performed to confirm our results and help reduce inter-observer bias.

RESULTS

The local rate of malignant upgrade when pure FEA is diagnosed on a breast needle core biopsy is 12%. Age at time of diagnosis, size of original lesion on mammogram, presence of atypical ductal hyperplasia (ADH) or atypical lobular hyperplasia on core needle biopsy, the use of vacuum-assisted biopsy (VAB), or concordant imaging did not significantly correlate with malignant upgrade risk. None of the patients who were managed with radiological follow-up had malignant upgrade during follow-up. Patients undergoing radiological follow-up alone were more likely to have a VAB, concordant imaging, and no concurrent ADH.

CONCLUSION

Our local malignant upgrade rate is consistent with published literature. We suggest radiological follow-up is a safe alternative in patients with pure flat epithelial atypia and concordant imaging, particularly those patients with small lesions in which microcalcifications can be removed completely with vacuum-assisted biopsy.

Flat epithelial atypia and the risk of sampling error: Determining the value of excision after image-guided core-needle biopsy

BACKGROUND

We determined the sampling error rate of flat epithelial atypia (FEA) and evaluated current guidelines recommending excisional biopsy.

METHODS

A retrospective review of consecutive excisional biopsies after image-guided core-needle biopsy identified patients with isolated FEA diagnosed between 2014 and 2018. Clinical and pathologic parameters were evaluated.

RESULTS

Twenty-five women with 27 biopsies were included. Based on pathologic review of original core specimens, 44.4% (N = 12) were accurately diagnosed as FEA. Upon excision, lesions were upgraded to ductal carcinoma in situ (N = 2) or invasive ductal carcinoma (N = 1) in 11.1% of cases. Older age, black race, hormone replacement, and calcifications in the image-guided biopsy specimen were associated with the presence of high-risk or malignant lesions in the excisional biopsy (all p ≤ 0.05).

CONCLUSIONS

In this study, FEA was frequently overcalled. However, lesions suspicious for FEA warrant excision due to their association with malignancy or high-risk lesions, which may necessitate further surgical management and/or risk-reducing strategies.

Sonographic Features of Flat Epithelial Atypia Manifesting as a Non-Mass-Like Lesion: A Case Report

Patient: Female, 47

Final Diagnosis: Flat epithelial atypia of the breast

Symptoms: —

Medication: —

Clinical Procedure: —

Specialty: Radiology

Atypical ductal hyperplasia and the risk of underestimation: tissue sampling method, multifocality, and associated calcification significantly influence the diagnostic upgrade rate based on subsequent surgical specimens

Background

Risk assessment and therapeutic options are challenges when counselling patients with an atypical ductal hyperplasia (ADH) to undergo either open surgery or follow-up only.

Methods

We retrospectively analyzed a series of ADH lesions and assessed whether the morphological parameters of the biopsy materials indicated whether the patient should undergo surgery. A total of 207 breast biopsies [56 core needle biopsies (CNBs) and 151 vacuum-assisted biopsies (VABs)] histologically diagnosed as ADH were analyzed retrospectively, together with subsequently obtained surgical specimens. All histological slides were re-analyzed with regard to the presence/absence of ADH-associated calcification, other B3 lesions (lesion of uncertain malignant potential), extent of the lesion, and the presence of multifocality.

Results

The overall underestimation rate for the whole cohort was 39% (57% for CNB, 33% for VAB). In the univariate analysis, the method of biopsy (CNB vs VAB, p = 0.002) and presence of multifocality in VAB specimens (p = 0.0176) were significant risk factors for the underestimation of the disease (ductal carcinoma in situ or invasive cancer detected on subsequent open biopsy). In the multivariate logistic regression model, the absence of calcification (p = 0.0252) and the presence of multifocality (unifocal vs multifocal ADH, p = 0.0147) in VAB specimens were significant risk factors for underestimation.

Conclusions

Multifocal ADH without associated calcification diagnosed by CNB tends to have a higher upgrade rate. Because the upgrade rate was 16.5% even in the group with the lowest risk (VAB-diagnosed unifocal ADH with calcification), we could not identify a subgroup that would not require an open biopsy.

Second International Consensus Conference on lesions of uncertain malignant potential in the breast (B3 lesions)

Purpose

The second International Consensus Conference on B3 lesions was held in Zurich, Switzerland, in March 2018, organized by the International Breast Ultrasound School to re-evaluate the consensus recommendations.

Methods

This study (1) evaluated how management recommendations of the first Zurich Consensus Conference of 2016 on B3 lesions had influenced daily practice and (2) reviewed current literature towards recommendations to biopsy.

Results

In 2018, the consensus recommendations for management of B3 lesions remained almost unchanged: For flat epithelial atypia (FEA), classical lobular neoplasia (LN), papillary lesions (PL) and radial scars (RS) diagnosed on core-needle biopsy (CNB) or vacuum-assisted biopsy (VAB), excision by VAB in preference to open surgery, and for atypical ductal hyperplasia (ADH) and phyllodes tumors (PT) diagnosed at VAB or CNB, first-line open surgical excision (OE) with follow-up surveillance imaging for 5 years. Analyzing the Database of the Swiss Minimally Invasive Breast Biopsies (MIBB) with more than 30,000 procedures recorded, there was a significant increase in recommending more frequent surveillance of LN [65% in 2018 vs. 51% in 2016 (p = 0.004)], FEA (72% in 2018 vs. 62% in 2016 (p = 0.005)), and PL [(76% in 2018 vs. 70% in 2016 (p = 0.04)] diagnosed on VAB. A trend to more frequent surveillance was also noted also for RS [77% in 2018 vs. 67% in 2016 (p = 0.07)].

Conclusions

Minimally invasive management of B3 lesions (except ADH and PT) with VAB continues to be appropriate as an alternative to first-line OE in most cases, but with more frequent surveillance, especially for LN.