Flat epithelial atypia: concepts and controversies of an intraductal lesion of the breast

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 diagnosed on core needle biopsy-Clinical challenge

AIM

This paper describes our experience of 20 cases identified in the FEA vacuum core biopsy.

BACKGROUND

Screening mammography has contributed to the increased recognition of early cancer, premalignant and preinvasive breast lesions. A premalignant lesion called FEA (flat epithelial atypia), although rarely recognized as the only lesion in the core biopsy, is a major challenge in clinical proceedings. Increasing recognition is associated with an increasing use of the vacuum core biopsy as a tool for verifying nonpalpable lesions identified by mammography, and suspected of being breast cancer.

MATERIALS AND METHODS

Of 4326 mammotome biopsies performed at our institution in 2000-2006, FEA was diagnosed in 20 patients (0.46%). These patients underwent surgery for reexcsion. Data were collected for clinical, radiological and pathological findings to assess factors associated with the underestimation of invasive lesions.

RESULTS

Among 20 patients with FEA diagnosis, the mean age was 59.6, range 52-71. When compared to the ADH group (mean age 55.45), the FEA patients were found to be statistically significantly older (p = 0.0002). Two patients 2/20 (10%) showed underestimation, with invasive cancer on the final pathology were G1 tubular cancer T1b, and G2 lobular cancer T1a.

CONCLUSION

Although FEA is rarely diagnosed as the only lesion in a core biopsy, the ever more common use of this diagnostic technique forces us to establish a clear clinical practice. The problem is the underestimation of invasive lesions in the case of primary diagnosis of FEA. It seems that some percent of these cases can be identified by certain radiological or pathological features, thus helping implement appropriate clinical management.

Clinicopathologic implications of "flat epithelial atypia" in core needle biopsy specimens of the breast

Flat epithelial atypia (FEA) is an emerging entity of uncertain clinical significance, and outcome data are sparse. The aim of this study was to evaluate the clinicopathologic significance of this entity for proper management. All core needle biopsy (CNB) specimens diagnosed as atypical ductal hyperplasia (ADH) from January 2006 to April 2008 were retrieved. H&E-stained slides of 5 levels on each case were reviewed. The differences in upstaging in subsequent excisions in the FEA and ADH group (31/189 [16.4%]) vs the pure FEA group (5/35 [14%]) and pure FEA (5/35 [14%]) vs pure ADH (5/45 [11%]) were not statistically significant. We observed that FEA evolved into ADH at the same site at an average of 3 to 4 levels. Our study concludes that there is an association of FEA with ADH on multiple levels of CNB specimens, and follow-up surgical excision findings for FEA are clinically significant.

Columnar cell lesions of the breast: an update and significance on core biopsy

Columnar cell lesions of the breast refer to the morphological spectrum of alterations of the epithelial lining of variably dilated acini of the terminal duct lobular unit (TDLU), often related to secretions and calcifications. After decades of varied terminologies, the term of 'flat epithelial atypia' by the World Health Organization (WHO) consensus group encompasses the part of the spectrum where columnar cell change or columnar cell hyperplasia acquires low grade cytological atypia, merging with atypical ductal hyperplasia and low grade ductal carcinoma in situ. Its association with low grade invasive carcinoma and lobular neoplasia, whether by proximity to these lesions, or by similar molecular expressions, has prompted greater scrutiny into its clinical significance. Although recent literature attempts to refine the term 'flat epithelial atypia', the applicability of its morphological criteria in routine diagnostic practice remains to be seen, and interobserver variability is highly possible. This poses even greater challenges especially in limited samples of breast tissue, such as in core biopsies, for pre-operative decision-making. The purpose of this review is to elucidate evolving clinical and diagnostically relevant principles that surround and influence the significance of this still controversial entity, especially when discovered on core biopsy in the initial phase of breast diagnosis and management.

Can mammographic findings help discriminate between atypical ductal hyperplasia and ductal carcinoma in situ after needle core biopsy?

In a screening population of women, the mammographic characteristics for 68 cases of atypical ductal hyperplasia (ADH) diagnosed by needle core biopsy (NCB) were reviewed to seek mammographic findings which differentiate between ductal carcinoma in situ (DCIS) and ADH. A blinded analysis by two radiologists was performed for 48 cases with microcalcification. The mammographic findings were correlated with the surgical histological results of benign non-atypical, ADH and carcinoma (DCIS or invasive) to identify features which were associated with a higher or lower odds ratio (OR) for malignancy. Underestimates for malignancy occurred in 14 of 29 cases with granular calcification form (OR 7.9, 95% confidence interval (CI) 1.5-41) and 6 of 8 cases with segmental/linear branching distribution (OR 9.0, 95%CI 1.6-52). No malignancy was found at surgical excision in 16 cases with fine, rounded calcification. In conclusion, detailed assessment of calcification distribution and form gave helpful predictors for malignancy. Lesions with fine rounded calcification were always benign.

Breast Screening in Singapore: Implications for Pathology

The aim of this review is to discuss the impact of breast screening on pathology. The advent of the national mammographic screening programme in Singapore has led to changes in the manner in which breast specimens are handled in the pathology laboratory, an increased detection of borderline lesions which pose diagnostic challenges, the occurrence of specific issues regarding core biopsies, and the need for awareness of histologic artefacts associated with preoperative needling procedures. There are also economic and workload implications, in addition to the essential requirement for quality assurance and educational programmes to maintain high professional standards. A multidisciplinary approach and commitment to continual professional upgrading are key to surmounting the pathologic challenges brought about by breast screening. Key words: Borderline lesions, Quality assurance, Radiologic calcifications, Workload

Lobular in situ neoplasia and columnar cell lesions: diagnosis in breast core biopsies and implications for management

Histopathologists are encountering intra-lobular epithelial proliferations more frequently in core biopsies taken from lesions identified in mammographic breast screening programmes. In particular, columnar cell lesions are increasingly being seen in core biopsies taken for the histological assessment of mammographically detected microcalcifications. The morphological features of lobular neoplasia are relatively well known, but columnar cell lesions, particularly forms with atypical features, are less widely recognised. The biological and clinical significance of both of these intra-lobular processes is controversial, (1) as indicators of adjacent malignancy when encountered in core biopsy, (2) the relative risk conferred of development of subsequent malignancy, and (3) their precursor behaviour. For this reason, the optimal clinical management of these lesions, particularly when encountered on core biopsy, is unclear. This review provides an update on the histological diagnosis of lobular neoplasia and columnar cell lesions and outlines recent clinico-pathological and molecular findings with discussion on clinical management.

Non-operative breast pathology: columnar cell lesions

The term "columnar cell lesions" encompasses a spectrum of processes, characterised by variably dilated acini, lined by one to several layers of tightly packed, columnar-shaped epithelial cells. These lesions have received renewed attention in the literature due to their high prevalence in biopsy specimens taken for assessment of mammographically detected microcalcification. In addition, increasing interest has been directed at the sub-set of columnar cell lesions with varying degrees of cytological atypia. Recent observational and molecular genetic studies have provided strong circumstantial evidence to suggest that at least some of these lesions may represent the earliest morphologically identifiable, non-obligate precursor of low grade breast carcinomas. However, the risk of both local recurrence and progression to invasive cancer appears to be exceedingly low. This review provides an update on recent clinicopathological and molecular data on columnar cell lesions and how these have changed our perception of, and the classification system for, these lesions. In addition, guidelines for the management of patients with columnar cell lesions diagnosed in core needle biopsy specimens are provided.

Characterization of columnar cell lesions of the breast: immunophenotypic analysis of columnar alteration of lobules with prominent apical snouts and secretions

Columnar cell lesions of the breast are detected with increasing frequency in routine pathology practice, in part as a result of the widespread biopsy of nonpalpable breast abnormalities detected by screening mammography. Immunohistochemical investigation of the lesions in relation to the normal breast or to other breast pathologies is not well characterized, and the malignant potential of this spectrum of lesions has not been examined clinically. In this study, a cohort of 45 breast specimens containing columnar cell lesions, in particular, columnar alteration of lobules with prominent apical snouts and secretions (CAPSS), was investigated for expression of a series of breast tumor biomarkers. Using a semiquantitative immunohistochemical scoring system, up-regulation of estrogen, progesterone, and androgen receptors in CAPSS lesions to levels not significantly different from that in in situ or invasive breast tumors was identified. In four cases where CAPSS within a specimen lacked expression of a steroid hormone receptor, the coexisting in situ or invasive carcinoma also lacked expression of that receptor. In 81% of CAPSS lesions, E-cadherin immunostaining was reduced in isolated foci of cells or was decreased in intensity in all cells within the lesion. Quantitation of Ki-67 immunostaining demonstrated that proliferation of cells within CAPSS lesions was increased, compared with normal breast epithelium, but was lower than that detected in in situ or invasive cancers within the same specimens. Results of these analyses indicate that CAPSS shares immunophenotypic alterations with other premalignant lesions, the clinical implications of which may be investigated using established breast tumor biomarkers.

Nuclear morphometry in columnar cell lesions of the breast: is it useful?

AIMS

To evaluate the nuclear morphometric features of breast columnar cell lesions (CCLs) observed on mammotome core biopsies, to determine if there are significant measurable differences between those with atypia and those without. Correlation with follow-up open excision specimens was made.

METHODS

Mammotome core biopsies performed on patients that contained CCLs were derived from the departmental case files. Histological material was reviewed and foci of CCLs demarcated for nuclear morphometric assessment, which was accomplished using an imaging system. Nuclear parameters studied were nuclear area and perimeter, circularity factor and feret's diameter. Statistical analysis used the GraphPad Prism software, with p<0.05 indicating significance.

RESULTS

On examination of core biopsies of 40 patients with CCLs, 8 lesions were benign, 4 showed atypical lobular hyperplasia, 8 showed CCLs with nuclear atypia, 19 disclosed atypical ductal hyperplasia (ADH) and 1 showed ductal carcinoma in situ (DCIS). The nuclear area, perimeter and feret's diameter of CCLs with atypia were significantly greater than those without (p = 0.04, 0.03 and 0.019, respectively), whereas no difference was observed in the circularity factor. Follow-up open excision biopsy specimens in 24 patients showed upgrading to DCIS in 40% of cases diagnosed initially with ADH on core biopsy compared with 20% of CCLs with atypia.

CONCLUSIONS

Nuclear morphometry in CCLs confirms nuclear size as the key parameter in the assessment of nuclear atypia. Whether it can be potentially used as an adjunctive tool depends on the establishment of appropriate cut-offs.