The significance of lobular neoplasia on needle core biopsy of the breast

Upgrade Rates of Variant Lobular Carcinoma In Situ Compared to Classic Lobular Carcinoma In Situ Diagnosed in Core Needle Biopsies: A 10-Year Single Institution Retrospective Study

The primary aim of this study was to determine the upgrade rates of variant lobular carcinoma in situ (V-LCIS, ie, combined florid [F-LCIS] and pleomorphic [P-LCIS]) compared with classic LCIS (C-LCIS) when diagnosed on core needle biopsy (CNB). The secondary goal was to determine the rate of progression/development of invasive carcinoma on long-term follow-up after primary excision. After institutional review board approval, our institutional pathology database was searched for patients with "pure" LCIS diagnosed on CNB who underwent subsequent excision. Radiologic findings were reviewed, radiologic-pathologic (rad-path) correlation was performed, and follow-up patient outcome data were obtained. One hundred twenty cases of LCIS were identified on CNB (C-LCIS = 97, F-LCIS = 18, and P-LCIS = 5). Overall upgrade rates after excision for C-LCIS, F-LCIS, and P-LCIS were 14% (14/97), 44% (8/18), and 40% (2/5), respectively. Of the total cases, 79 (66%) were deemed rad-path concordant. Of these, the upgrade rate after excision for C-LCIS, F-LCIS, and P-LCIS was 7.5% (5 of 66), 40% (4 of 10), and 0% (0 of 3), respectively. The overall upgrade rate for V-LCIS was higher than for C-LCIS (P = .004), even for the cases deemed rad-path concordant (P value: .036). Most upgraded cases (23 of 24) showed pT1a disease or lower. With an average follow-up of 83 months, invasive carcinoma in the ipsilateral breast was identified in 8/120 (7%) cases. Six patients had died: 2 of (contralateral) breast cancer and 4 of other causes. Because of a high upgrade rate, V-LCIS diagnosed on CNB should always be excised. The upgrade rate for C-LCIS (even when rad-path concordant) is higher than reported in many other studies. Rad-path concordance read, surgical consultation, and individualized decision making are recommended for C-LCIS cases. The risk of developing invasive carcinoma after LCIS diagnosis is small (7% with ∼7-year follow-up), but active surveillance is required to diagnose early-stage disease.

Malignancy Rate and Malignancy Risk Assessment in Different Lesions of Uncertain Malignant Potential in the Breast (B3 Lesions): An Analysis of 192 Cases from a Single Institution

BACKGROUND

The question of how to deal with B3 lesions is of emerging interest.

METHODS

In the breast diagnostics of 192 patients between 2009 and 2016, a minimally invasive biopsy revealed a B3 lesion with subsequent resection. This study investigates the malignancy rate of different B3 subgroups and the risk factors that play a role in obtaining a malignant finding.

RESULTS

The distribution of B3 lesions after minimally invasive biopsy was as follows: atypical ductal hyperplasia (ADH), 7.3%; flat epithelial atypia (FEA), 7.8%; lobular neoplasia (LN), 7.8%; papilloma (Pa), 49.5%; phylloidal tumour (PT), 8.9%; radial sclerosing scar (RS), 3.1%; mixed findings, 10.4%; and other B3 lesions, 5.2%. Most B3 lesions were detected by stereotactic vacuum-assisted biopsy (44.3%), 36.5% by ultrasound-assisted biopsy, and 19.3% by magnetic resonance imaging-assisted biopsy. Most B3 lesions (55.2%) were verified by surgical resection, whereas 30.7% were downgraded to a benign lesion. About 14.1% of the cases were upgraded to malignant lesions, 9.4% to ductal carcinoma in situ and 4.7% to invasive carcinoma. In relation to individual B3 lesions, the following malignancy rates were found: 28.6% (ADH), 13.3% (FEA), 33.3% (LN), 12.6% (Pa), 5.9% (PT), and 0% (RS). The most important risk factor was increasing age. Postmenopausal status was considered an increased risk for an upgrade (p = 0.015). A known malignancy in the ipsilateral breast was a significant risk factor for a malignant upgrade (p = 0.003).

CONCLUSION

Increasing knowledge about B3 lesions allows us to develop a "lesion-specific" therapy approach in the heterogeneous group of B3 lesions, with follow-up imaging for some lesions with less malignant potential and concordance with imaging or further surgical resection in cases of disconcordance with imaging or higher malignant potential.

Risk for Upgrade to Malignancy After Breast Core Needle Biopsy Diagnosis of Lobular Neoplasia: A Systematic Review and Meta-Analysis

PURPOSE

Lobular neoplasia (LN) detected on breast core needle biopsy is frequently managed with surgical excision because of concern for undersampled malignancy. The authors performed a systematic review and meta-analysis to estimate the risk for upgrade to malignancy in the setting of imaging-concordant classic LN diagnosed on core biopsy.

METHODS

PubMed and Embase were searched for original articles published from 1998 to 2020 that reported rates of upgrade to malignancy for classic LN, including atypical lobular hyperplasia (ALH) and classic lobular carcinoma in situ (LCIS). Two reviewers extracted study data and assessed the following quality criteria: exclusion of variant LCIS, exclusion of imaging-discordant lesions, and outcome reporting for ≥70% of lesions. For studies meeting all criteria, pooled risks for upgrade to any malignancy (invasive carcinoma or ductal carcinoma in situ) and invasive malignancy for all LN, ALH, and LCIS were estimated using random-effects models.

RESULTS

For 65 full-text articles included in the review, the risk for upgrade to any malignancy ranged from 0% to 45%. Among the 16 studies that met all quality criteria for the meta-analysis, pooled risks for upgrade to any malignancy were 3.1% (95% confidence interval [CI], 1.8%-5.2%) for all LN, 2.5% (95% CI, 1.6%-3.9%) for ALH, and 5.8% (95% CI, 2.9%-11.3%) for LCIS. Risks for upgrade to invasive malignancy were 1.3% (95% CI, 0.7%-2.4%) for all LN, 0.4% (95% CI, 0.0%-4.2%) for ALH, and 3.5% (95% CI, 2.0%-5.9%) for LCIS.

CONCLUSIONS

The risk for upgrade to malignancy for LN found on breast biopsy is low. Imaging surveillance can likely be offered as an alternative to surgical management for LN, particularly for ALH.

Pitfalls and controversies in pathology impacting breast cancer management

Introduction: Breast cancer is a heterogeneous disease, at morphological, molecular, and clinical levels and this has significant implications for the diagnosis and management of the disease. The introduction of breast screening, and the use of small tissue sampling for diagnosis, the recognition of new morphological and molecular subtypes, and the increasing use of neoadjuvant therapies have created challenges in pathological diagnosis and classification.Areas covered: Areas of potential difficulty include columnar cell lesions, particularly flat epithelial atypia, atypical ductal hyperplasia, lobular neoplasia and its variants, and a range of papillary lesions. Fibroepithelial, sclerosing, mucinous, and apocrine lesions are also considered. Established and newer prognostic and predictive markers, such as immune infiltrates, PD-1 and PD-L1 and gene expression assays are evaluated. The unique challenges of pathology assessment post-neoadjuvant systemic therapy are also explored.Expert opinion: Controversies in clinical management arise due to incomplete and sometimes conflicting data on clinicopathological associations, prognosis, and outcome. The review will address some of these challenges.

Outcomes of classic lobular neoplasia diagnosed on breast core needle biopsy: a retrospective multi-center study

Management of classic lobular neoplasia (cLN) diagnosed on core needle biopsy (CNB) is controversial. Our aim in this study was to review cases of cLN diagnosed on CNB to determine the rate and risk factors of an upgrade to ductal carcinoma in situ (DCIS) or invasive carcinoma on excision. All breast CNBs with a diagnosis of atypical lobular hyperplasia (ALH) or classic lobular carcinoma in situ (cLCIS) from three different institutions within a single health care system between 2013 and 2018 were retrieved. Cases with any additional high-risk lesions in the same CNB or discordant radiological-pathological correlation were excluded. Information about age, personal history of prior or concurrent breast cancer (P/CBC), and radiological and histological findings were recorded. A total of 287 cLN cases underwent surgical excision. Analysis of these 287 cLN cases showed 11 (3.8%) upgrade lesions on excision. Among the 172 ALH cases, there were 3 (1.7%) upgrades, which were all invasive lobular carcinomas (ILCs). On the other hand, 8 of 115 (7%) cLCIS cases revealed upgrade on excision (2 ILC, 5 DCIS. and 1 ILC + DCIS). Statistical analysis revealed that cLN cases with P/CBC, radiological asymmetry, or architectural distortion had a statistically significant higher upgrade rate on excision. Our findings revealed a low upgrade rate (3.8%) on the excision of classic lobular neoplasia diagnosed on breast core needle biopsy. Clinicoradiological surveillance can be appropriate when lobular neoplasia is identified on core biopsy with pathological radiological concordance in patients without a history of breast cancer, with the caveat that radiological asymmetry and architectural distortion are associated with a significant increase in an upgrade on excision.

Outcome of radial scar/complex sclerosing lesion associated with epithelial proliferations with atypia diagnosed on breast core biopsy: results from a multicentric UK-based study

AIMS

The clinical significance of radial scar (RS)/complex sclerosing lesion (CSL) with high-risk lesions (epithelial atypia) diagnosed on needle core biopsy is not well defined. We aimed at assessing the upgrade rate to ductal carcinoma in situ (DCIS) and invasive carcinoma on the surgical excision specimen in a large cohort with RS/CSL associated with atypia.

METHODS

157 women with a needle core biopsy diagnosis of a RS/CSL with atypia and follow-up histology were studied. Histological findings, including different forms of the atypical lesions and final histological outcome in the excision specimens, were retrieved and analysed, and the upgrade rates for malignancy and for invasive carcinoma were calculated.

RESULTS

69.43% of the cases were associated with atypical ductal hyperplasia (ADH) or atypia not otherwise classifiable, whereas lobular neoplasia was seen in 21.66%. On final histology, 39 cases were malignant (overall upgrade rate of 24.84%); 12 were invasive and 27 had DCIS. The upgrade differed according to the type of atypia and was highest for ADH (35%). When associated with lobular neoplasia, the upgrade rate was 11.76%. The upgrade rate's variability was also considerably lower when considering the upgrade to invasive carcinoma alone for any associated lesion.

CONCLUSIONS

The upgrade rate for ADH diagnosed on needle core biopsy with RS is similar to that of ADH without RS and therefore should be managed similarly. RS associated with lobular neoplasia is less frequently associated with malignant outcome. Most lesions exhibiting some degree of atypia showed a similar upgrade rate to invasive carcinoma. Management of RS should be based on the concurrent atypical lesion.

Observation versus excision of lobular neoplasia on core needle biopsy of the breast

PURPOSE

Controversy surrounds management of lobular neoplasia (LN), [atypical lobular hyperplasia (ALH) or lobular carcinoma in situ (LCIS)], diagnosed on core needle biopsy (CNB). Retrospective series of pure ALH and LCIS reported "upgrade" rate to DCIS or invasive cancer in 0-40%. Few reports document radiologic/pathologic correlation to exclude cases of discordance that are the likely source of most upgrades, and there is minimal data on outcomes with follow-up imaging and clinical surveillance.

METHODS

Cases of LN alone on CNB (2001-2014) were reviewed. CNB yielding LN with other pathologic findings for which surgery was indicated were excluded. All patients had either surgical excision or clinical follow-up with breast imaging. All cases included were subject to radiologic-pathologic correlation after biopsy.

RESULTS

178 cases were identified out of 62213 (0.3%). 115 (65%) patients underwent surgery, and 54 (30%) patients had surveillance for > 12 months (mean = 55 months). Of the patients who underwent surgical excision, 13/115 (11%) were malignant. Eight of these 13 found malignancy at excision when CNB results were considered discordant (5 DCIS, and 3 invasive lobular carcinoma), with the remainder, 5/115 (4%), having a true pathologic upgrade: 3 DCIS, and 2 microinvasive lobular carcinoma. Among 54 patients not having excision, 12/54 (22%) underwent subsequent CNB with only 1 carcinoma found at the initial biopsy site.

CONCLUSIONS

Surgical excision of LN yields a low upgrade rate when careful consideration is given to radiologic/pathologic correlation to exclude cases of discordance. Observation with interval breast imaging is a reasonable alternative for most cases.

Lobular Carcinoma In Situ

Lobular carcinoma in situ (LCIS) is a risk factor and a nonobligate precursor of breast carcinoma. The relative risk of invasive carcinoma after classic LCIS diagnosis is approximately 9 to 10 times that of the general population. Classic LCIS diagnosed on core biopsy with concordant imaging and pathologic findings does not mandate surgical excision, and margin status is not reported. The identification of variant LCIS in a needle core biopsy specimen mandates surgical excision, regardless of radiologic-pathologic concordance. The presence of variant LCIS close to the surgical margin of a resection specimen is reported, and reexcision should be considered.

Current Concepts in Diagnosis, Molecular Features, and Management of Lobular Carcinoma In Situ of the Breast With a Discussion of Morphologic Variants

Context.—

Lobular carcinoma in situ (LCIS) refers to a neoplastic proliferation of cells that characteristically shows loss of E-cadherin expression and has long been regarded as a risk factor for invasive breast cancer. Long-term outcome studies and molecular data have also implicated LCIS as a nonobligate precursor to invasive carcinoma. In the past few decades, pleomorphic and florid LCIS have been recognized as morphologic variants of LCIS with more-aggressive histopathologic features, less-favorable biomarker profiles, and more-complex molecular features compared with classic LCIS. There is still a lack of consensus regarding certain aspects of managing patients with LCIS.

Objectives.—

To review recently published literature on LCIS and to provide an overview of the current morphologic classification of LCIS, recent molecular advances, and trends in patient management.

Data Sources.—

Sources included peer-reviewed, published journal articles in PubMed (US National Library of Medicine, Bethesda, Maryland) and published guidelines from the National Comprehensive Cancer Network (Fort Washington, Pennsylvania).

Conclusions.—

Lobular carcinoma in situ represents a marker for increased risk of breast cancer, as well as a nonobligate precursor to invasive carcinoma. Morphologic variants of LCIS—florid and pleomorphic LCIS—are genetically more-complex lesions and are more likely to be associated with invasive carcinoma. Further investigation into which molecular alterations in LCIS are associated with progression to invasive carcinoma is needed to help guide medical and surgical management.

Surgical upgrade rate of breast atypia to malignancy: An academic center's experience and validation of a predictive model

Atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), and lobular carcinoma in situ (LCIS) are commonly seen on breast core needle biopsy (CNB). Many institutions recommend excision of these lesions to exclude malignancy. A retrospective chart review was performed on patients who had ADH, ALH, or LCIS on breast CNB from 1/1/08 to 12/31/10 who subsequently had surgical excision of the biopsy site. Study objectives included determining upgrade to malignancy at surgical excision, identification of predictors of upgrade, and validation of a recently published predictive model. Clinical and demographic factors, pathology, characteristics of the biopsy procedure and visible residual lesion were recorded. T test and chi-squared test were used to identify predictors. Classification tree was used to predict upgrade. 151 patients had mean age of 53 years. The mean maximum lesion size on imaging was 11 mm. The primary atypia was ADH in 63.6%, ALH in 27.8%, and LCIS in 8.6%. 16.6% of patients had upgrade to malignancy, with 72% DCIS and 28% invasive carcinoma. Risk factors for upgrade included maximum lesion size (P = .002) and radiographic presence of residual lesion (P = .001). A predictive model based on these factors had sensitivity 78%, specificity 80% and AUC = 0.88. Validating a published nomogram with our data produced accuracy figures (AUC = 0.65) within published CI of 0.63-0.82. In CNB specimens containing ADH, ALH, or LCIS, initial lesion size and presence of residual lesion are predictors of upgrade to malignancy. A validated model may be helpful in developing patient management strategies.

Surgical implications and variability in the use of the flat epithelial atypia diagnosis on breast biopsy specimens

OBJECTIVES

Flat epithelial atypia (FEA) is a relatively new diagnostic term with uncertain clinical significance for surgical management. Any implied risk of invasive breast cancer associated with FEA is contingent upon diagnostic reproducibility, yet little is known regarding its use.

MATERIALS AND METHODS

Pathologists in the Breast Pathology Study interpreted one of four 60-case test sets, one slide per case, constructed from 240 breast biopsy specimens. An electronic data form with standardized diagnostic categories was used; participants were instructed to indicate all diagnoses present. We assessed participants' use of FEA as a diagnostic term within: 1) each test set; 2) 72 cases classified by reference as benign without FEA; and 3) six cases classified by reference as FEA. 115 pathologists participated, providing 6900 total independent assessments.

RESULTS

Notation of FEA ranged from 0% to 35% of the cases interpreted, with most pathologists noting FEA on 4 or more test cases. At least one participant noted FEA in 34 of the 72 benign non-FEA cases. For the 6 reference FEA cases, participant agreement with the case reference FEA diagnosis ranged from 17% to 52%; diagnoses noted by participating pathologists for these FEA cases included columnar cell hyperplasia, usual ductal hyperplasia, atypical lobular hyperplasia, and atypical ductal hyperplasia.

CONCLUSIONS

We observed wide variation in the diagnosis of FEA among U.S. pathologists. This suggests that perceptions of diagnostic criteria and any implied risk associated with FEA may also vary. Surgical excision following a core biopsy diagnosis of FEA should be reconsidered and studied further.

Lobular carcinoma in situ of the breast - correlation between minimally invasive biopsy and final pathology

INTRODUCTION

Lobular carcinoma in situ (LCIS) is regarded as a non-obligate precursor of invasive breast cancer (IBC). Hence, the optimal management of LCIS found on minimally invasive breast biopsy remains a subject of debate. The aim of this study was to evaluate the correlation of biopsy findings with postoperative histology and to identify risk factors for upstaging to IBC.

MATERIAL AND METHODS

Twenty-seven patients with pure LCIS diagnosed on image-guided biopsy (vacuum-assisted or core-needle) underwent subsequent surgery. Clinical, radiological and histological features were compared to the final pathology after surgical excision.

RESULTS

Median age of patients was 56 years while median size of LCIS was 15 mm. Final examination demonstrated IBC foci in 29.6% of lesions. Upstaged patients were younger and had larger lesions but without statistical significance (p = 0.07 and p = 0.09, respectively). Palpable tumours (p = 0.0004), BIRADS 5 lesions (p = 0.0001), masses (p = 0.016) and pleomorphic LCIS (p = 0.0001) had a significantly increased rate of upstaging. Guidance of the procedure (ultrasound vs. stereotactic) was significantly associated with the upstaging risk (p = 0.016), while the importance of the biopsy technique (core-needle vs. vacuum-assisted) was not confirmed (p = 0.37). After excluding pleomorphic LCIS and mass-forming classic LCIS, there was no risk of upstaging for lesions with BIRADS 4 mammographic abnormalities.

CONCLUSIONS

Pleomorphic histology, mass formation and BIRADS 5 category reflect more aggressive behaviour of LCIS and identify patients who need subsequent surgery. For other patients, close follow-up could be a safe alternative.

When pathological and radiological correlation is achieved, excision of fibroadenoma with lobular neoplasia on core biopsy is not warranted

BACKGROUND

The diagnosis and management of lobular neoplasia (LN) including lobular carcinoma in situ (LCIS) and atypical lobular hyperplasia (ALH) remains controversial. Current management options after a core needle biopsy (CNB) with lobular neoplasia (LN) incorporating both ALH and LCIS include excision biopsy or careful clinical and radiologic follow up.

METHODS

A retrospective analysis of the surgical database at Cork University Hospital was performed to identify all core needle biopsies from January 1st 2010 to 31st December 2013 with a diagnosis of FA who subsequently underwent surgical excision biopsy. All cases with associated LN including ALH and classical LCIS were selected. We excluded cases with coexistent ductal carcinoma in situ (DCIS), invasive carcinoma, LN associated with necrosis, pleomorphic lobular carcinoma in situ (PLCIS) or lesions which would require excision in their own right (papilloma, radial scar, atypical ductal hyperplasia (ADH) or flat epithelial atypia (FEA)). Cases in which the radiologic targeted mass was discordant with a diagnosis of FA were also excluded.

RESULTS

2878 consecutive CNB with a diagnosis of FA were identified. 25 cases had a diagnosis of concomitant ALH or classical LCIS. Our study cohort consisted of 21 women with a mean age 53 years (age range 41-70 years). The core biopsy diagnosis was of LCIS and FA in 16 cases and ALH and FA in 5 cases. On excision biopsy, a FA was confirmed in all 21 cases. In addition to the FA, residual LCIS was present in 14 cases with residual ALH in 2 cases. One of the twenty-one cases (4.8%) was upgraded to invasive ductal carcinoma on excision.

Core Breast Biopsies Showing Lobular Carcinoma In Situ Should Be Excised and Surveillance Is Reasonable for Atypical Lobular Hyperplasia

OBJECTIVE

The purpose of this article is to determine the upgrade rate to ductal carcinoma in situ (DCIS) or invasive carcinoma at excision at the same site after percutaneous breast biopsy findings of atypical lobular hyperplasia (ALH) or lobular carcinoma in situ (LCIS) using current imaging and strict pathologic criteria.

MATERIALS AND METHODS

From January 2006 through September 2013, 32,960 breast core biopsies were performed; 1084 (3.3%) core biopsies found ALH or classic LCIS. For 447 lesions in 433 women, this was the only high-risk lesion at that site, with no ipsilateral malignancy, and results of excision were available.

RESULTS

Among the 447 lesions, 22 (4.9%) were malignant at excision, including 10 invasive carcinomas (two grade 2 and eight grade 1; all node negative) and 12 DCIS. The upgrade rate of LCIS was 9.3% (10/108; 95% CI, 5.1-16.2%) and that of ALH was 3.5% (12/339; 95% CI, 2.0-6.1%; p = 0.02). After excluding five cases with radiologic-pathologic discordance and reclassifying one core from ALH to LCIS at review, the upgrade rate for LCIS remained higher (8.4%; 9/107; 95% CI, 4.5-15.2%) than that for ALH (2.4%; 8/335; 95% CI, 1.2-4.6%; p = 0.01).

CONCLUSION

Excision is recommended for LCIS on core biopsy because of its 8.4-9.3% upgrade rate. Excluding discordant cases, patients with other high-risk lesions or concurrent malignancy, the risk of upgrade of ALH was 2.4%. Surveillance at 6, 12, and 24 months can be performed in lieu of excision because a short delay in diagnosis of the few malignancies is not expected to cause harm.

UK national survey of management of breast lobular carcinoma in situ

INTRODUCTION

There is no national standard treatment for patients with breast lobular carcinoma in situ (LCIS). Association of Breast Surgery guidelines for the management of breast cancer suggest that lesions containing LCIS should be excised for definitive diagnosis and recommend close surveillance after excision biopsy. The aim of this study was to form a picture of the current management of LCIS by UK breast surgeons.

METHODS

A questionnaire about the management of LCIS was sent to 490 UK breast surgeons.

RESULTS

Of 490 questionnaires sent out, 173 (35%) were returned. When LCIS is present in a core biopsy, 61% of breast surgeons perform surgical excision, 22% would not excise but would continue follow-up and the remainder perform neither or set no clear management plan. Over half (54%) follow patients up with five years of annual mammography. If classic LCIS were found at the margins of wide local excision, 92% would not re-excise. Conversely, if pleomorphic LCIS were found, 71% would achieve clear margins. Respondents were split evenly regarding management of classic LCIS with a family history as 54% would not alter management whereas 43% would treat the disease more aggressively.

CONCLUSIONS

Our survey has shown that in cases where LCIS is found at core biopsy, most surgeons follow Association of Breast Surgery guidance, obtaining further histological samples to exclude pleomorphic LCIS, ductal carcinoma in situ or invasive cancer, whereas others opt for annual surveillance and some discharge the patient. This study highlighted the huge variability in LCIS management, and the need for randomised controlled trials and input into national audits such as the Sloane Project to establish evidence-based national standard guidelines.

Diagnostic utility of E-cadherin and P120 catenin cocktail immunostain in distinguishing DCIS from LCIS

BACKGROUND

Breast carcinoma in situ (CIS) is classified into ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS). DCIS is treated with surgical excision while LCIS can be clinically followed with or without hormonal treatment. Thus, it is critical to distinguish DCIS from LCIS. Immunohistochemical (IHC) staining for E-cadherin is routinely used to differentiate DCIS from LCIS in diagnostically challenging cases. Circumferential diffuse membranous staining of E-cadherin is the typical pattern in DCIS, whereas LCIS lacks or shows decreased E-cadherin expression. Recent studies have shown that DCIS has membranous staining of P120 catenin and LCIS has diffuse cytoplasmic staining of P120 catenin. We developed a cocktail composed of E-cadherin and P120 catenin primary antibodies so that only one slide is needed for the double immunostains.

DESIGNS

Twenty-seven blocks of formalin-fixed paraffin-embedded tissue from 26 cases of DCIS or LCIS were retrieved from the archives of Houston Methodist Hospital. Four consecutive sections from the same blocks were used for H&E and immunohistochemical (IHC) stains. The E-cadherin antibody was a rabbit polyclonal antibody and the P120 catenin antibody was a mouse monoclonal antibody. The E-cadherin primary antibody was detected using a secondary antibody raised against rabbit antibody and was visualized with a brown color. The P120 catenin primary antibody was detected using a secondary antibody raised against mouse antibody and was visualized with a red color.

RESULTS

Using individual antibodies, 15 of 15 DCIS lesions had diffuse circumferential membranous E-cadherin staining (brown stain) or P120 catenin staining (red stain). All 12 LCIS cases showed cytoplasmic P120 red staining or loss of E-cadherin staining when the single P120 catenin or E-cadherin antibody was used. When stained with the antibody cocktail, all 15 DCIS samples showed diffuse red and brown membranous staining without cytoplasmic stain; all 12 LCIS samples showed diffuse cytoplasmic red staining for P120 catenin but no membranous staining for E-cadherin.

CONCLUSIONS

1. This antibody cocktail can be applied in daily practice on paraffin-embedded tissue and is especially useful in small biopsies with small foci of CIS lesions. 2. Immunohistochemical staining with the antibody cocktail showed 100% concordance with the traditional single antibody immunostaining using either E-cadherin or P120 catenin antibody. 3. Our antibody cocktail includes E-cadherin as a positive membranous stain for DCIS and P120 catenin as a positive cytoplasmic stain for LCIS, which may enhance accuracy and confidence in the differential diagnoses.

When is excision necessary for atypical lobular hyperplasia and lobular carcinoma in situ?

SUMMARY This management perspective briefly covers the histology and molecular features of lobular in situ neoplasia and provides an in-depth discussion of the need for surgical excision if lobular in situ neoplasia is diagnosed on core-needle biopsy. The management of lobular in situ neoplasia found on core-needle biopsy has been an area of recent study with varying results. Emerging data suggest that low-risk patients with a limited extent of isolated classic lobular in situ neoplasia found on core-needle biopsy may not require subsequent surgical excision. However, high-risk patients, those with extensive lobular in situ neoplasia, or other high-risk lesions noted on core-needle biopsy likely benefit from surgical excision. Most authors recommend surgical excision when pleomorphic lobular carcinoma in situ is found on core-needle biopsy due to its higher association with invasive carcinoma. However, the natural history of this more recently described variant of lobular carcinoma in situ is not fully defined, and the clinical management of pleomorphic lobular carcinoma in situ on excisional biopsy is yet to be determined.

Pleomorphic lobular carcinoma in situ of the breast: clinicopathological review of 47 cases

AIMS

Pleomorphic lobular carcinoma in situ (PLCIS) of the breast is a distinctive entity, but its behaviour and management are unclear. The purpose of this study was to review a relatively large number of cases and to evaluate the risk of recurrence.

METHODS AND RESULTS

Cases of PLCIS (n = 47) from a 12-year period were reviewed. The clinical, radiological and pathological findings were recorded. Immunohistochemistry for oestrogen receptor (ER), progesterone receptor (PR) and HER2 was performed. Thirty-one patients had no concurrent breast cancer or past history of breast cancer, and six (19.4%) of these had local recurrence; all tumours (four invasive carcinoma and two PLCIS) were ipsilateral. Younger age at presentation was a risk factor for local recurrence: patients with recurrence had a mean age (range) of 52.5 years (44-59 years), versus 60.6 years (40-81 years) for those without (P = 0.03). Three of 31 patients were treated with radiation therapy (RT), and none of these developed local recurrence. PLCIS had an adverse ER/PR/HER2 molecular profile, with at least 41.2% of the cases overexpressing HER2. Moreover, at least 11.7% of the cases were triple-negative.

CONCLUSIONS

This study included the largest number of patients who had no concurrent breast cancer or past history of breast cancer with the longest clinical follow-up, providing insights into management practices for PLCIS and the risk of recurrence.

Upgrade of high-risk breast lesions detected on mammography in the Breast Cancer Surveillance Consortium

BACKGROUND

Upgrade rates of high-risk breast lesions after screening mammography were examined.

METHODS

The Breast Cancer Surveillance Consortium registry was used to identify all Breast Imaging Reporting and Data System category 4 assessments followed by needle biopsies with high-risk lesions. Follow-up was performed for all women.

RESULTS

High-risk lesions were found in 957 needle biopsies, with excision documented in 53%. Most (n = 685) were atypical ductal hyperplasia (ADH), 173 were lobular neoplasia, and 99 were papillary lesions. Upgrade to cancer varied with type of lesion (18% in ADH, 10% in lobular neoplasia, and 2% in papillary lesions). In premenopausal women with ADH, upgrade was associated with family history. Cancers associated with ADH were mostly (82%) ductal carcinoma in situ, and those associated with lobular neoplasia were mostly (56%) invasive. During a further 2 years of follow-up, cancer was documented in 1% of women with follow-up surgery and in 3% with no surgery.

CONCLUSIONS

Despite low rates of surgery, low rates of cancer were documented during follow-up. Benign papillary lesions diagnosed on Breast Imaging Reporting and Data System category 4 mammograms among asymptomatic women do not justify surgical excision.

Pathologic Upgrade Rates on Subsequent Excision When Lobular Carcinoma In Situ Is the Primary Diagnosis in the Needle Core Biopsy With Special Attention to the Radiographic Target

Context.—Lobular carcinoma in situ (LCIS) as the primary pathologic diagnosis in a needle core biopsy is an infrequent finding, and the management of patients in this setting is controversial.

Objective.—To determine the rate of pathologic upgrade (defined as the presence of a clinically more-significant lesion in the subsequent excision) in patients with a primary pathologic diagnosis of LCIS in the needle core biopsy.

Design.—Patients with a primary diagnosis of LCIS in a needle core biopsy who underwent subsequent excision were identified. Core biopsies containing a concurrent high-risk lesion and cases with radiologic-pathologic discordance were excluded. The presence of selected microscopic features in the needle core biopsy was correlated with pathologic upgrade. Microscopic findings were correlated with the radiographic target in the needle core biopsy.

Results.—Sixty-one women with primary LCIS in their needle core biopsy showed a 10% pathologic upgrade rate. The percentage of cores involved by LCIS was significantly associated with pathologic upgrade (P= .04), whereas the remaining measured parameters were not. When LCIS represented the radiographic target, the pathologic upgrade rate was 18%, whereas when it was an incidental finding, the pathologic upgrade rate was 4%.

Conclusions.—It may be reasonable for patients with primary, yet incidental, LCIS on needle core biopsy to be managed in a nonsurgical fashion. Larger studies are needed to confirm our findings.

Classic lobular neoplasia on core biopsy: a clinical and radio-pathologic correlation study with follow-up excision biopsy

There are no consensus guidelines for the management of lobular neoplasia diagnosed on core biopsy as the highest risk factor for cancer. This study aimed to assess the risk of upgrade (invasive carcinoma or ductal carcinoma in situ) at the site of the lobular neoplasia and any clinical, radiological or pathologic factors associated with the upgrade. We reviewed all cases with a diagnosis of lobular neoplasia on core biopsy from June 2006 to June 2011. Any cases with radio-pathologic discordance, coexistent lesion that required excision (atypical ductal hyperplasia, flat epithelial atypia, duct papilloma or radial scar) or non-classic variant of lobular carcinoma in situ (pleomorphic, mixed ductal and lobular, lobular carcinoma in situ with necrosis) were excluded from the study. Core biopsy indications included calcification in 35 (40%), non-mass like enhancement in 19 (22%), mass lesion in 31 (36%) and mass as well as calcification in two cases (2%). Follow-up excisions were studied for the presence of upgrade. The study cohort included 87 cases and showed an upgrade of 3.4% (95% confidence interval: 1-10%). Three cases showed an upgrade (one ductal carcinoma in situ and two invasive cancers). All upgraded cases were breast imaging-reporting and data system score ≥4 and associated with atypical duct hyperplasia or in situ or invasive cancer in prior or concurrent biopsies in either breast. The number of cores and lobules involved, pagetoid duct involvement, presence of microcalcification in lobular neoplasia, needle gauge and number of cores obtained showed no correlation with the upgrade. Our results suggest that with radio-pathologic concordance and no prior biopsy proven risk for breast cancer, core biopsy finding of lobular neoplasia as the highest risk lesion can be appropriately and safely managed with clinical and radiologic follow-up as an alternative to surgical excision.

Morphological parameters of lobular in situ neoplasia in stereotactic 11-gauge vacuum-assisted needle core biopsy do not predict the presence of malignancy on subsequent surgical excision

AIMS

The management of lobular in situ neoplasia (LN) when diagnosed on core biopsy remains a controversial issue. The present study aimed to investigate the association between morphological parameters of LN on vacuum-assisted needle core biopsy (VANCB) and the presence of malignancy (ductal carcinoma in situ, pleomorphic lobular carcinoma in situ, or invasive carcinoma) at surgical excision (SE).

METHODS AND RESULTS

The study included 14 pathology departments in Italy. Available slides from 859 cases of VANCB reporting an original diagnosis of flat epithelial atypia, atypical ductal hyperplasia or LN, all with subsequent surgical excision, were reviewed. Overall, 286 cases of LN, pure or associated with other lesions, were identified, and a malignant outcome was reported at excision for 51 cases (17.8%). Among the 149 cases of pure LN, an increased risk of malignancy emerged in women in mammographic categories R4-R5 as compared with those in categories R2-R3 (OR 2.46; P = 0.048). In the series, a statistically significant decreased malignancy risk emerged among cases without determinant microcalcifications (P = 0.04).

CONCLUSIONS

Our results suggest that the diagnosis of pure LN on VANCB warrants follow-up excision, because clinicopathological parameters do not allow the prediction of which cases will present carcinoma at surgical excision.

[Pleomorphic lobular intraepithelial neoplasia: clinical, histological and prognostic study of nine cases]

INTRODUCTION

Retrospective clinical, histological and prognostic study of nine cases of lobular intraepithelial neoplasia in its pleomorphic subtype (LIN-P).

PATIENTS AND METHODS

Analysis of our center database with selection of nine cases of LIN-P from 140 files of patients who underwent surgical excision with a final diagnosis of LIN (2000 to 2011). The medical files were reviewed with a re-analysis of the mammograms and the histological slides. The outcome of the patients was also analyzed according to their clinical and operative data.

RESULTS AND DISCUSSION

The average age at diagnosis was 63 years (later than common LIN [LIN-C]). All patients had mammograms classified ACR 4 and 5, mainly due to the presence of microcalcifications (seven cases) with a case of opacity associated with microcalcifications, and two other cases with only isolated opacities. The preoperative diagnosis of these lesions was difficult: five cases on nine core needle biopsies were reviewed and reclassified LIN-P after finding the presence of LIN-P on the surgical specimen. Associated invasive lesions were found in 55% of core needle biopsy and in 33% of cases of surgical resection specimen. The treatment included a wide surgical excision (five lumpectomies and four mastectomies with a patient who had two lumpectomies) with margins of more than 2mm: we noted a recurrence of LIN-P only in one case where margins were very close (1mm). The analysis of our cases confirms that LIN-P if they probably share the same origin as the LIN-C represent a particular form constituting a true precancerous condition warranting at least a wide surgical excision.

Long-term follow-up of lobular neoplasia (atypical lobular hyperplasia/lobular carcinoma in situ) diagnosed on core needle biopsy

BACKGROUND

Lobular neoplasia (LN) includes atypical lobular hyperplasia (ALH) and lobular carcinoma in situ (LCIS). LN often is an incidental finding on breast core needle biopsy (CNBx) and management remains controversial. Our objective was to define the incidence of malignancy in women diagnosed with pure LN on CNBx, and identify a subset of patients that may be observed.

METHODS

Patients diagnosed with LN on CNB between January 1993 and December 2010 were identified. Patients with an associated high-risk lesion or ipsilateral malignancy at time of diagnosis were excluded. All cases were reviewed by dedicated breast pathologists and breast imagers for pathologic classification and radiologic concordance, respectively.

RESULTS

The study cohort was comprised of 184 (1.3 %) cases of pure LN (147 ALH, 37 LCIS) from 180 patients. Pathologic-radiologic concordance was achieved in 171 (93 %) cases. Excision was performed in 101 (55 %) cases and 83 (45 %) were observed. Mean follow-up was 50.3 (range, 6-212) months. Of cases excised, 1 of 81 (1.2 %) ALH and 1 of 20 (5 %) LCIS cases were upstaged to ductal carcinoma in situ (DCIS) and invasive lobular carcinoma (ILC), respectively. Only 1 of 101 (1 %) concordant lesions was upstaged on excision. Of the cases observed, 4 of 65 (6.2 %) developed ipsilateral cancer during follow-up: 1 of 51 (2 %) case of ALH and 3 of 14 (21.4 %) cases with LCIS (2 ILC, 2 DCIS). During follow-up, 2.9 % (4/138) patients with excised or observed LN developed a contralateral cancer.

CONCLUSIONS

These data support that not all patients with LN diagnosed on CNB require surgical excision. Patients with pure ALH, demonstrating radiologic-pathologic concordance, may be safely observed.

Pathologic findings of follow-up surgical excision for lobular neoplasia on breast core biopsy performed for calcification

This study aimed to ascertain pathologic findings of surgical follow-up excision (FUE) on patients who had radiologic finding of calcifications and lobular neoplasia (LN) on core biopsy. Breast core biopsy specimens from 2006-2011 with a diagnosis of pure classic-type LN (lobular carcinoma in situ [LCIS] and atypical lobular hyperplasia [ALH]) with no history of invasive carcinoma (IC) or ductal carcinoma in situ (DCIS) were studied. Two hundred thirty-seven patients with the diagnosis of calcium on radiologic studies had FUE and were included in the study. Cases were divided into group 1 (pure ALH, n = 163) and group 2 (pure LCIS, n = 74). The interval between the core biopsy and FUE ranged from 0.2 to 7 months (mean, 1.5 ± 1.1 months). The risk of upstaging on FUE (DCIS or IC) is as follows: LCIS, 8.1% (6/74) and ALH, 3.1% (5/163). The data indicate that there is a low risk of upstaging to DCIS/IC from a core biopsy diagnosis of lobular neoplasia.

Low frequency of cancer occurrence in same breast quadrant diagnosed with lobular neoplasia at percutaneous needle biopsy

PURPOSE

To determine the type of mammographic abnormality leading to needle biopsy of lobular neoplasia (LN) and define the clinical evolution of low-risk LN lesions diagnosed at needle biopsy but not surgically removed.

MATERIALS AND METHODS

This study was approved by the institutional review board, and the requirement to obtain informed consent was waived. Among 16 945 needle biopsies performed between April 1998 and August 2008, LN was determined to be the most suspicious lesion in 352 samples (2.1%) (pleomorphic and necrotic forms were excluded). Among 299 pure LN lesions that were not surgically removed, follow-up was available for 276 lesions in 275 women.

RESULTS

Needle biopsy was performed because of mammographic calcifications in 215 of the 276 lesions (77.9%) and because of mammographic masses in 35 (12.7%). The mean follow-up was 5.0 years ± 2.4 (range, 0.6-12.2 years). All 275 women underwent one mammographic follow-up, 205 (74.5%) underwent a second mammographic follow-up, and 147 (53.5%) underwent a third mammographic follow-up. Cancer was diagnosed in 27 of the 275 cases (9.8%) after a mean of 3.9 years ± 2.6 (range, 1.2-10.8 years). Only three cancers (1.1%) occurred in the same breast quadrant as the one originally diagnosed with LN at needle biopsy.

CONCLUSION

Lumpectomy of pure LN lesions may not prevent malignancy in most cases. Consequently, women with pure LN of a low-risk type diagnosed at needle biopsy are strongly encouraged to undergo a yearly breast clinical examination and yearly mammographic follow-up to detect an eventual cancer in its early stages.

In situ lobular neoplasia of the breast with marked myoepithelial proliferation

AIMS

To present four new cases of in situ lobular neoplasia associated with marked proliferation of myoepithelial cells.

METHODS AND RESULTS

Four recently seen cases showing extensive foci of in situ lobular neoplasia, as confirmed by negative E-cadherin staining, were stained for myoepithelial cells using CD10, smooth muscle actin and cytokeratin 5/6. Invasive lobular carcinoma was also present in two cases; one case was associated with multiple foci of collagenous spherulosis, and one was associated with a radial scar. Marked myoepithelial proliferation was seen around most of the in situ lobular foci or mingled with lobular cells.

CONCLUSIONS

Marked proliferation of myoepithelial cells is sometimes encountered in association with extensive in situ lobular neoplasia. It is suggested that this proliferation might have a role in maintaining the in situ status of these lesions or, alternatively, that there is a shared factor responsible for the simultaneous proliferation of certain 'lobular' cell types and myoepithelial cells.

Outcome of breast lesions diagnosed as lesion of uncertain malignant potential (B3) or suspicious of malignancy (B4) on needle core biopsy, including detailed review of epithelial atypia

AIMS

To provide updated evidence of the outcome of breast lesions of uncertain malignant potential (B3) and suspicious of malignancy (B4) diagnosed on needle core biopsy (NCB) and analyse the outcome of the different types of intraductal epithelial atypia.

METHODS AND RESULTS

One-hundred and forty-nine B3 and 26 B4 NCBs diagnosed over a 2-year period (2007-2008) were compared with those diagnosed over a previous 2-year period (1998-2000). The proportion of B3 diagnoses increased from 3.1% to 4.5%, and the positive predictive value (PPV) of malignancy of a B3 core decreased from 25% to 10%. Increased diagnosis of radial scar and reductions in the PPV of lobular neoplasia and of atypical intraductal proliferation may explain the reduction in the PPV of the B3 group as a whole. There were no significant changes in the proportion of B4 diagnosis (1.1% and 0.8%) or the PPV of B4 (83% and 88%). Review of cores with intraductal atypia showed a wide range of PPVs, from 100% for suspicious of ductal carcinoma in situ, to 40% for atypical ductal hyperplasia categorized as B3, and 14% for isolated flat epithelial atypia.

CONCLUSION

The study has found a decrease in the PPV for a B3 diagnosis and suggests possible explanations.

Positive predictive value for malignancy on surgical excision of breast lesions of uncertain malignant potential (B3) diagnosed by stereotactic vacuum-assisted needle core biopsy (VANCB): a large multi-institutional study in Italy

Percutaneous core biopsy (CB) has been introduced to increase the ability of accurately diagnosing breast malignancies without the need of resorting to surgery. Compared to conventional automated 14 gauge needle core biopsy (NCB), vacuum-assisted needle core biopsy (VANCB) allows obtaining larger specimens and has recognized advantages particularly when the radiological pattern is represented by microcalcifications. Regardless of technical improvements, a small percentage of percutaneous CBs performed to detect breast lesions are still classified, according to European and UK guidelines, in the borderline B3 category, including a group of heterogeneous lesions with uncertain malignant potential. We aimed to assess the prevalence and positive predictive values (PPV) on surgical excision (SE) of B3 category (overall and by sub-categories) in a large series of non-palpable breast lesions assessed through VANCB, also comparison with published data on CB. Overall, 26,165 consecutive stereotactic VANCB were identified in 22 Italian centres: 3107 (11.9%) were classified as B3, of which 1644 (54.2%) proceeded to SE to establish a definitive histological diagnosis of breast pathology. Due to a high proportion of microcalcifications as main radiological pattern, the overall PPV was 21.2% (range 10.6%-27.3% for different B3 subtypes), somewhat lower than the average value (24.5%) from published studies (range 9.9%-35.1%). Our study, to date the largest series of B3 with definitive histological assessment on SE, suggests that B3 lesions should be referred for SE even if VANCB is more accurate than NCB in the diagnostic process of non-palpable, sonographically invisible breast lesions.

Lobular carcinoma in situ/atypical lobular hyperplasia on breast needle biopsies: does it warrant surgical excisional biopsy? A study of 27 cases

Lobular neoplasia including lobular carcinoma in situ (LCIS) and atypical lobular hyperplasia (ALH) may be identified in breast core needle biopsies as incidental findings or associated with microcalcifications. There are no general consensus guidelines for follow-up management in patients when lobular neoplasia is the only abnormal finding on core needle biopsy. The aim of this study was to evaluate our experience in the follow-up of these patients. A total of 3163 breast core needle biopsies were retrieved from the surgical pathology files between 2003 and 2009; among them, 56 (1.8%) cases were identified with a diagnosis of ALH or LCIS. Eleven cases were excluded because of the presence of a concurrent more severe lesion in the biopsies that mandated excision. The remaining 45 cases contained only ALH or LCIS and otherwise benign breast tissue; 27 had surgical excision follow-up. In the surgical excision specimens, 5 (19%) of 27 cases showed more severe lesions or were "upgraded" (3 invasive ductal carcinomas, 1 invasive lobular carcinoma, and 1 ductal carcinoma in situ). Histologic features of the lobular neoplasia on the cores, including association with microcalcifications, pagetoid involvement of ducts, and extensive lobular involvement, were retrospectively evaluated. These histologic features were found to have no predictive value for a more severe lesion in the subsequent excision. We suggest that patients with LCIS/ALH on core needle biopsy should be considered for surgical excision to rule out a more significant lesion regardless of the histologic features.

Screen-detected pleomorphic lobular carcinoma in situ (PLCIS): risk of concurrent invasive malignancy following a core biopsy diagnosis

AIMS

Pleomorphic lobular carcinoma in situ (PLCIS) is an uncommon, recently recognized variant of lobular carcinoma in situ (LCIS). Its natural history, biological behaviour and clinical characteristics are uncertain. The aim was to review the radiological and pathological findings in a series of screen-detected PLCIS diagnosed on needle core biopsy with a view to determining the diagnostic features, immunohistological profile and risk of concurrent invasive malignancy.

METHODS AND RESULTS

Ten cases of core biopsy-diagnosed, screen-detected PLCIS were identified. Core biopsy findings were compared with pathological findings at subsequent surgery. Two cases were associated with possible microinvasion on the core. Two of 10 had invasive lobular carcinoma and one had microinvasive lobular carcinoma on subsequent surgical excision (positive predictive value for malignancy = 30%). There was associated conventional LCIS on either core or excision biopsy in all cases except one. All three cases of oestrogen receptor (ER)-negative PLCIS arose in the context of ER+ conventional LCIS.

CONCLUSIONS

PLCIS is a potentially more aggressive lesion than conventional LCIS and may present as mammographic calcification through a breast screening programme. Diagnosis may be problematic and immunohistochemical markers including ER may prove a useful diagnostic adjunct. There is a significant risk of concurrent invasive carcinoma following a core biopsy diagnosis.

Lobular neoplasia displaying central necrosis: a potential diagnostic pitfall

The distinction between intraepithelial proliferations of ductal and lobular type is often straightforward. However, a small number of cases create diagnostic problems even for experienced pathologists. Among those is the recognized, but not always kept in mind, lobular neoplasia with "comedo-type" necrosis. Herein, we present six cases of lobular neoplasia with comedo necrosis. Three cases were classified correctly, whereas the three remaining cases were initially misdiagnosed as ductal carcinoma in situ with necrosis. Of these three misdiagnosed cases, one patient underwent radiation therapy before this study was carried out. The two other patients were correctly reclassified as lobular type in subsequent excisional biopsies. One case showed a focus of microinvasion. All six lesions were negative by E-cadherin immunohistochemistry. Our experience highlights that the correct differentiation between intraepithelial neoplasias of ductal and lobular type may be challenging, and that the correct differentiation is extremely important for prognostic information and therapeutic decisions.

Early Breast Cancer Precursor Lesions: Lessons Learned from Molecular and Clinical Studies

Atypical ductal hyperplasia (ADH), flat epithelial atypia (FEA), and lobular neoplasia (LN) form a group of early precursor lesions that are part of the low-grade pathway in breast cancer development. This concept implies that the neoplastic disease process begins at a stage much earlier than in situ carcinoma. We have performed a review of the published literature for the upgrade risk to ductal carcinoma in situ or invasive carcinoma in open biopsy after a diagnosis of ADH, FEA, or LN in core needle biopsy. This has revealed the highest upgrade risk for ADH (28.2% after open biopsy), followed by LN (14.9%), and FEA (10.2%). With LN, the pleomorphic subtype is believed to confer a higher risk than classical LN. With all types of precursor lesions, careful attention must be paid to the clinicopathological correlation for the guidance of the clinical management. Follow-up biopsies are generally indicated in ADH, and if there is any radiological-pathological discrepancy, also in LN or FEA.

Lobular neoplasia: morphology, biological potential and management in core biopsies

Lobular neoplasia has been traditionally recognized as a marker of increased risk for subsequent breast carcinoma development; however, molecular studies suggest that it also behaves in a non-obligate precursor manner. We do not know, as yet, how to identify the subgroup of cases that is most likely to progress, but the epidemiological data would indicate that this progression occurs after a long period of time. Thus, the current approach of conservative management of these lesions when identified in excision specimens is justified. Recently, several variants of lobular carcinoma in situ (LCIS), most notably pleomorphic LCIS, have been recognized and these can be difficult to differentiate from ductal carcinoma in situ. Application of strict diagnostic criteria and the judicial use of immunohistochemistry, particularly E-cadherin, can be helpful in this differential diagnosis. Another challenging issue is the management of lobular neoplasia when diagnosed on core biopsy. This controversial issue will be discussed in detail. The goals of this review are (1) to describe the morphological criteria used to diagnose the spectrum of lobular neoplastic lesions, including atypical lobular hyperplasia, LCIS and variants of LCIS; (2) to discuss the data exploring the biological potential of lobular neoplasia from an epidemiological and molecular viewpoint; and (3) to outline the recommendations for management of lobular neoplasia when encountered in core biopsies.