Medullary breast carcinoma: a pathogenic review and immunohistochemical study using tissue microarray.

Introduction: Medullary breast carcinomas (MBCs) are distinguished by circumscribed, high-grade morphology with dense chronic inflammation; they are associated with the basal phenotype but have a relatively good prognosis. Methods: This study aimed to review the clinicopathological features of MBCs diagnosed at the Department of Pathology, Singapore General Hospital and correlate them with immunohistochemical expression of hormonal markers and c-erbB-2, the basal markers p53, cytokeratin (CK) 14, epidermal growth factor receptor (EGFR) and 34BE12, and the follow-up outcome. Results: Using Ridolfi's criteria for histologic reviews, 62 patients previously diagnosed as having 'typical MBC' (n = 26), 'atypical MBC' (n = 32) and 'invasive carcinoma with focal medullary-like features' (n = 4) were re-classified as follows: 'typical MBC' (n = 6; 9.7%), 'atypical MBC' (n = 46; 74.2%), and 'non-medullary infiltrating carcinoma' (n = 10; 16.1%). Clinicopathological parameters, including ethnicity, age, tumour size and concurrent ductal carcinoma in situ (DCIS), showed no statistically significant correlation with review diagnoses and immunohistochemical findings. Presence of lymphovascular invasion and nodal stage were significantly correlated with recurrence and breast cancer-related deaths, respectively. ER negativity was significantly correlated with triple positivity for basal markers CK14, EGFR and 34BE12, which comprised patients who showed a significantly decreased disease-free survival rate within a 10-15-year follow-up period. Conclusions: Lymphovascular invasion and high nodal stage as well as triple negativity among typical and atypical MBCs that have basal-like phenotype represent a portion of invasive carcinomas with medullary features that may have poor outcomes in this otherwise relatively good prognostic group.

Triple-negative breast cancer: clinicopathological characteristics and relationship with basal-like breast cancer.

Triple-negative breast cancer, defined as that with negative expression of estrogen and progesterone receptors and cerbB2, accounted for 11% of invasive breast cancers in our study, drawn from an original cohort of 7048 women diagnosed with breast cancer from the files of the Department of Pathology, Singapore General Hospital, over 14 years. Women with triple-negative breast cancer were generally postmenopausal, with adverse pathological characteristics of high histological grade and frequent nodal metastases. Using a set of 61 invasive breast cancers earlier profiled into molecular subtypes with expression arrays, we defined specificity and sensitivity values for different immunohistochemical panels of basal keratins (CK5/6, CK14, CK17, 34 beta E12), CD117, EGFR, p63 and SMA in defining basal-like breast cancer. Subsequent application of a tri-panel of CK14, EGFR and 34 beta E12 (specificity 100% and sensitivity 78%) to our group of 653 triple-negative breast cancers delineated 84% to be basal-like. Immunohistochemical expression of individual biological markers correlated with unfavorable pathological parameters. We conclude that triple-negative breast cancers in an Asian population harbor adverse pathobiological features, and an immunohistochemical surrogate panel can be reliably used to define basal-like cancers among them.

Predictors of phyllodes tumours on core biopsy specimens of fibroepithelial neoplasms.

AIMS: To establish histological and biological parameters that can predict phyllodes tumours on core biopsy specimens of indeterminate fibroepithelial neoplasms. METHODS AND RESULTS: Core biopsy specimens of fibroepithelial lesions diagnosed at the Department of Pathology, Singapore General Hospital from 2002 to 2007 were reviewed. Cases in which phyllodes tumour was favoured, or could not be ruled out, were evaluated for stromal cellularity/distribution, nuclear atypia and mitoses, stromal overgrowth, epithelial fronding, epithelial hyperplasia, configuration of lesional edge, presence of pseudoangiomatous stromal hyperplasia and of adipose tissue. Antibodies to Ki67, topoisomerase IIalpha, CD34, CD117 and Bcl-2 were applied to sections subjected to immunohistochemistry using the streptavidin-biotin method. Findings were correlated with subsequent excisions. Of 261 core biopsy specimens of fibroepithelial lesions, 98 (37%) comprised cases in which phyllodes tumour could not be excluded and 57 (58%) had subsequent open surgical excisions. Marked stromal hypercellularity (5/5; 100%) and nuclear atypia (1/1; 100%), stromal overgrowth (17/17; 100%), mitoses > or =2/10 high-power fields (18/18; 100%) and ill-defined lesional borders (16/16 phyllodes tumours; 100%) were features in core biopsy specimens that exclusively predicted phyllodes tumour on excision. Moderate stromal hypercellularity (20/27 phyllodes tumours; 74%), stromal overgrowth, moderate nuclear atypia (14/16 phyllodes tumours; 87%), pseudoangiomatous stromal hyperplasia (19/23 phyllodes tumours; 83%) significantly correlated with their subsequent excisions. Immunohistochemical markers Ki67 > or =5% and topoisomerase IIalpha> or =5%, and reduced or patchy CD34 on core biopsy specimens correlated significantly with a diagnosis of phyllodes. CONCLUSIONS: Stromal hypercellularity, combined with key histological features and immunohistochemical markers Ki67, topoisomerase IIalpha and CD34, reinforced by clinical findings, can predict phyllodes tumours on core biopsy specimens.

Papillary lesions of the breast--accuracy of core biopsy.

AIMS: To assess the accuracy of diagnosing papillary breast lesions in core needle biopsy. METHODS AND RESULTS: One hundred biopsy specimens of papillary breast lesions were reviewed and compared with the final excisional diagnoses. The discordant biopsy specimens were stained for oestrogen receptor (ER), cytokeratin (CK) 14 and p63, and these specimens were reclassified based on these results. The overall core biopsy accuracy, false-positive and false-negative rate were 79%, 5% and 16%, respectively. A benign core biopsy specimen diagnosis gave a false-negative rate of 10%, and malignant core biopsy specimen diagnosis did not give any false-positive results. Using homogeneous ER (epithelial), positive CK14 (epithelial) and p63 (myoepithelial) immunoreactivity as benign criteria, the discordant rate was reduced by 30% and 69% when using all three or two of these three criteria for diagnosis. However, false-positive and -negative cases could not be totally eliminated. CONCLUSIONS: Immunohistochemistry is helpful in core biopsy diagnosis of papillary breast lesions, but some cases remained misdiagnosed.

Mucin extravasation in breast core biopsies--clinical significance and outcome correlation.

AIMS: To document the spectrum of lesions associated with mucin extravasation (ME) in breast core biopsy specimens, and to correlate with open surgical excisions. METHODS AND RESULTS: Thirty-nine lesions in 37 women with ME on core biopsies constituted the study group. Fibrocystic change (FC), atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS) were found in 21 (53.8%), 13 (33.3%) and four (10.3%) core biopsy specimens, respectively, with one (2.6%) consisting only of mucin pools. Except for the latter, all disclosed mucocoele-like lesions (MLL) accompanying ME. Columnar cell lesions (CCL) were frequently observed (84.6%). On open biopsy, three cases underdiagnosed on core biopsy included FC that later disclosed ADH; one ADH lesion on core later upgraded to DCIS; and a case of mucin pools that revealed mucinous carcinoma on excision. The extent of CCL on core biopsy appeared to predict sinister lesions on open excision. For calcified lesions that were completely removed on core biopsy, there were no malignant lesions discovered on open excision that had not already been diagnosed preoperatively. CONCLUSIONS: ME and MLL on core biopsy warrant close radiological-pathological correlation. When the entire radiological abnormality has been removed with large core mammotome biopsy specimens, surgery may potentially be avoided in histologically benign lesions, although such an approach requires further validation.

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.

Pattern and spectrum of morphology referrals in breast pathology consultation.

AIMS: We aimed to identify common reasons for second opinion breast pathology referrals at the Pathology Department, Singapore General Hospital, focusing on queries and diagnostic issues raised by referring clinicians and pathologists. METHODS: Request forms for breast pathology consultations were retrieved from a specialist's correspondence files consisting of pathologists' referrals, and from centralised laboratory records, comprising clinician-initiated referrals. Clinical and histomorphological queries raised by the referrals were collated. RESULTS: Of 299 cases evaluated, clinician-initiated referrals (n = 137, 46%) included requests for review of overall histopathology to confirm carcinoma subtype (n = 47), grade (n = 2), size (n = 4), lymphovascular invasion (n = 1) and confirm hormonal receptor and c-erbB-2 assays (n = 33). Also required were: comparison of recurrent with previous lesions (n = 8); settling discrepant diagnoses between two or more prior pathology reports (n = 4); verification of microinvasion (n = 6), in situ carcinomas (n = 6) or atypical ductal hyperplasias (n = 4); delineation of benign (n = 8) and spindle cell lesions (n = 3); to establish a breast origin of metastatic lesions (n = 5); and distinction of carcinoma from lymphoma (n = 2). Pathologist-initiated referrals (n = 162, 54%) sought arbitration between borderline proliferative lesions (n = 46) and papillary lesions (n = 34); verification of microinvasion (n = 23), stromal lesions (n = 16), and carcinoma subtype (n = 13), especially if the patient was young (n = 5); clarification of metaplastic changes (n = 4) and lobular neoplasia (n = 8); and comparison of fibroepithelial lesions (n = 11). CONCLUSIONS: Clinicians sought a second opinion mainly to verify histological diagnoses and report important pathological details for staging and confirmation of hormonal receptor and c-erbB-2 status prior to therapy. Borderline breast lesions are worrisome for both clinicians and pathologists in view of implications for management.

Using computer assisted image analysis to determine the optimal Ki67 threshold for predicting outcome of invasive breast cancer.

BACKGROUND: Ki67 positivity in invasive breast cancers has an inverse correlation with survival outcomes and serves as an immunohistochemical surrogate for molecular subtyping of breast cancer, particularly ER positive breast cancer. The optimal threshold of Ki67 in both settings, however, remains elusive. We use computer assisted image analysis (CAIA) to determine the optimal threshold for Ki67 in predicting survival outcomes and differentiating luminal B from luminal A breast cancers. METHODS: Quantitative scoring of Ki67 on tissue microarray (TMA) sections of 440 invasive breast cancers was performed using Aperio ePathology ImmunoHistochemistry Nuclear Image Analysis algorithm, with TMA slides digitally scanned via Aperio ScanScope XT System. RESULTS: On multivariate analysis, tumours with Ki67 ≥14% had an increased likelihood of recurrence (HR 1.941, p=0.021) and shorter overall survival (HR 2.201, p=0.016). Similar findings were observed in the subset of 343 ER positive breast cancers (HR 2.409, p=0.012 and HR 2.787, p=0.012 respectively). The value of Ki67 associated with ER+HER2-PR<20% tumours (Luminal B subtype) was found to be <17%. CONCLUSION: Using CAIA, we found optimal thresholds for Ki67 that predict a poorer prognosis and an association with the Luminal B subtype of breast cancer. Further investigation and validation of these thresholds are recommended.

Ultrasound Breast Elastographic Evaluation of Mass-Forming Ductal Carcinoma-in-situ with Histological Correlation - New Findings for a Toothpaste Sign.

BACKGROUND: It is unclear as to whether the size ratio elastographic technique is useful for assessing ultrasound- detected ductal carcinoma-in-situ (DCIS) masses since they commonly lack a significant desmoplastic reaction. The objectives of this study were to determine the accuracy of this elastographic technique in DCIS and examine if there was any histopathological correlation with the grey-scale strain patterns. MATERIALS AND METHODS: Female patients referred to the radiology department for image-guided breast biopsy were prospectively evaluated by ultrasound elastography prior to biopsy. Histological diagnosis was the gold standard. An elastographic size ratio of more than 1.1 was considered malignant. Elastographic strain patterns were assessed for correlation with the DCIS histological architectural patterns and nuclear grade. RESULTS: There were 30 DCIS cases. Elastographic sensitivity for detection of malignancy was 86.7% (26/30). 10/30 (33.3%) DCIS masses demonstrated predominantly white elastographic strain patterns while 20/30 (66.7%) were predominantly black. There were 3 (10.0%) DCIS masses that showed had a co-existent bull's-eye sign and 7 (23.3%) other masses had a co-existent toothpaste sign, a strain pattern that has never been reported in the literature. Four out of 4/5 comedo DCIS showed a predominantly white strain pattern (p=0.031) while 6/7 cases with the toothpaste sign were papillary DCIS (p=0.031). There was no relationship between the strain pattern and the DCIS nuclear grade. CONCLUSIONS: The size ratio elastographic technique was found to be very sensitive for ultrasound-detected DCIS masses. While the elastographic grey-scale strain pattern should not be used for diagnostic purposes, it correlated well with the DCIS architecture.

Syndecan-1 is a potential biomarker for triple-positive breast carcinomas in Asian women with correlation to survival.

INTRODUCTION: While overexpression of syndecan-1 has been associated with aggressive breast cancer in the Caucasian population, the expression pattern of syndecan-1 in Asian women remains unclear. Triple-positive breast carcinoma, in particular, is a unique subtype that has not been extensively studied. We aimed to evaluate the role of syndecan-1 as a potential biomarker and prognostic factor for triple-positive breast carcinoma in Asian women. METHODS: Using immunohistochemistry, staining scores of 61 triple­positive breast carcinoma specimens were correlated with patients' clinicopathological variables such as age, ethnicity, tumour size, histological grade, lymph node status, lymphovascular invasion, associated ductal carcinoma in situ grade, recurrence and overall survival. RESULTS: Syndecan-1 had intense staining scores in triple­positive invasive ductal breast carcinomas when compared to normal breast tissue. On multivariate analysis, syndecan-1 epithelial total percentage and immunoreactivity score showed statistical correlation with survival (p = 0.02). CONCLUSION: The intense staining scores of syndecan-1 and their correlation with overall survival in patients with triple-positive breast carcinoma suggest that syndecan-1 may have a role as a biological and prognostic marker in patients with this specific subtype of breast cancer.

Assessment of suitability of the one step nucleic acid amplification (OSNA) assay as an intraoperative procedure for detection of metastasis in sentinel lymph nodes of breast cancer.

AIM: We aimed to assess the one step nucleic acid amplification (OSNA) assay as an intraoperative method in comparison with frozen sections (FS) for detection of metastasis in sentinel lymph nodes (SLNs) of breast cancer. METHOD: 100 SLNs from patients with breast carcinoma were enrolled within a 3-month period. Alternate 2 mm node slices were subjected to routine FS, and later to permanent histology, and the rest for automated molecular detection of CK19 mRNA using OSNA. FS and OSNA findings were compared with permanent histology results. Difference in turnaround time was also noted. RESULTS: With permanent histology as gold standard, OSNA was discrepant in 8 of 98 (3 false negative, 5 false positive) included SLNs whereas FS had 2 false negative cases. FS had higher sensitivity (89%, p=<0.001), specificity (100%, p=0.001) and concordance rate (98%) than OSNA (83%, 94% and 92%, respectively). FS showed almost perfect agreement (κ=0.929) whereas OSNA showed substantial agreement (κ=0.740) when compared with permanent histology. OSNA turnaround time was twice longer (mean of 47.7 min) than FS. CONCLUSIONS: Automation of SLN assessment using OSNA is a potentially useful intraoperative diagnostic tool with acceptable accuracy. Discordant findings in this study may be due to sampling allocation. Since OSNA is more time-consuming, its practical advantage over routine FS requires further study in view of current technical workflow considerations.

Intranuclear inclusions in epithelial cells of benign proliferative breast lesions.

AIM: To document and clarify the nature of intranuclear inclusions of luminal epithelium in benign proliferative breast lesions. METHODS AND RESULTS: Five benign breast lesions were selected which showed intranuclear inclusions within epithelial cells on light microscopy. Following confirmation of their luminal epithelial (non-myoepithelial) localisation by immunohistochemistry, ultrastructural examination was performed with the following observations: (1) presence of deep nuclear indentations occasionally verging on nuclear inclusions; (2) inclusions with features of helioid bodies; and (3) a morphological spectrum of helioid bodies and their focal coexistence. CONCLUSION: Intranuclear inclusions of breast epithelium are likely of cytoplasmic origin. Helioid bodies may be formed by a stepwise process, the nature of which needs further study.

Breast cancer in Singapore: some perspectives.

Breast cancer is the commonest malignancy among Singapore women, accounting for 29.7% of all female cancers, with an age-standardized rate of 54.9 per 100,000 per year. It has been the most frequent cancer in Singapore women for the last 30 years, with the highest rates previously reported in those aged between 45 and 49 years, but with a more recent observation of a change in peak age group to women in their late 50s. About 1,100 new cases are diagnosed annually and approximately 270 women die in Singapore each year from breast cancer. In the multiethnic population of Singapore, it has been noted that rising breast cancer incidence is consistent across all three ethnic groups (Chinese, Malays, and Indians). Singapore has among the highest breast cancer incidence in Asia. Possible explanations include rapid urbanization, improvement in socio-economic status, and adoption of a western lifestyle. Our experience with the Singapore breast screening pilot project (1994-1997) and the national breast-screening program (BreastScreen Singapore) has led to increased understanding of this disease in the country. Data from the pilot project showed that breast screening is just as effective in a predominantly Asian population as in the west. Early breast cancer accounted for most breast cancers detected, with pre-invasive ductal carcinoma in situ (DCIS) comprising 26% of all screen-detected cancers in the pilot study. In the currently on-going BreastScreen Singapore, DCIS forms >30% of all breast cancers among pre-menopausal women, a relatively high proportion probably accounted for partially by the greater participation of women aged between 40 and 49 years. Despite the ready availability of subsidized mammographic screening, there are still women in Singapore who present with locally advanced breast cancer. Clinical management of an increasing number of women with breast cancer embraces a multidisciplinary team-based approach, with regular discussions of therapeutic strategies at tumor boards. In order to improve breast cancer diagnostics and therapeutics in our country, it is important that there are continual breast cancer and breast disease-related educational activities for medical professionals engaged in diagnosing and managing breast cancer. The role of public education in raising awareness is also essential.

Digital pathology: exploring its applications in diagnostic surgical pathology practice.

There has been a recent upsurge in worldwide attention on digital pathology, which has transformed from static snapshots from camera-equipped microscopes to its modern form that encompasses scanning of whole glass slides with evaluation of histological images on a computer screen, along with management of its accompanying information. Although it has been widely accepted in education and research, its implementation in diagnostic surgical pathology practice is not without challenges in workflow integration, technological infrastructure, pathologist acclimatisation, global standardisation for clinical practice, and cost issues, among others. Nonetheless, early adopters have harnessed its benefits in specific niches, like frozen section services and remote second opinion consultations. Its tremendous potential is worthy of further validation to compare with conventional glass slide evaluation, even while it is already paving the way for advancement into virtual three-dimensional imaging technology, with a glimpse into a possible future digital diagnostic pathology practice.

Diagnostic issues in second opinion consultations in prostate pathology.

AIM: The increase in early detection of prostate cancer in the Asian population has bolstered second opinion consultations in prostate pathology in this region. In this review, we aimed to identify the spectrum of lesions and queries submitted to a pathologist with uropathology interest at the Singapore General Hospital. METHOD: Request forms for second opinion prostate consultations from pathologists and clinicians were retrieved from central laboratory records and a specialist's correspondence files within 2004-2007. Histomorphological queries raised in the referrals, and comparison of original diagnosis and Gleason scoring with the review diagnoses were collated. RESULTS: Discordant diagnoses (183/323, 57%) were more common than concordant diagnoses (143/326, 44%) between original diagnosis and subspecialist review. The majority of discordances comprised initial undergrading of Gleason scores (132/183, 72%; p < 0.01) especially in needle core biopsies. Among the significantly altered pathological diagnoses, 24 cases (13%; p < 0.01) were changed from benign to malignant (n = 9, 5%; p < 0.01), and malignant to benign (n = 11, 6%; p < 0.01) or high grade prostatic intraepithelial neoplasia (n = 4, 2%; p < 0.01). Benign mimics of malignancy such as atypical adenomatous hyperplasia and atrophy, and small foci of adenocarcinoma, were some examples of morphological pitfalls. CONCLUSION: Prostate biopsy review is important because of management and prognostic implications that vary among Gleason scores, and predictive parameters that are detailed in prostate pathology reports.

Molecular pathogenesis of progression and recurrence in breast phyllodes tumors.

Breast phyllodes tumors are rare fibroepithelial neoplasms that need to be distinguished from the common morphologically similar fibroadenomas, because phyllodes tumors can recur and progress to malignancy. Their potentially recurring and metastasizing behavior is attributed to their stromal characteristics, for which categorization between benign, borderline and malignant tumors have not been universally established. Previous clonality studies revealing monoclonal stromal cells versus a polyclonal epithelial component theorized that phyllodes tumors are mainly stromal neoplasms, possibly arising from fibroadenomas. More recent chromosomal imbalances in both epithelium and stroma have challenged this theory to favor neoplasia of both epithelium and stroma, with initial interdependence between the two components. Inverse correlations between epithelial and stromal overexpression for various biological markers like estrogen receptor, p53, c-kit, Ki-67, endothelin-1, epidermal growth factor receptor, heparan sulfate, in addition to findings of epithelial Wnt signalling with stromal insulin growth factors and beta-catenin expression, suggest an initial epithelial-stromal interdependence at the benign phase. Upon progression to malignancy, the stroma is hypothesized to assume an autonomous growth overriding any epithelial influence. Frequent genetic alterations are chromosomal gains of 1q and losses at chromosome 13. Acquisition of new genetic imbalances within the tumor consistent with intratumoral heterogeneity, and subclones within histologically benign phyllodes tumors that recur or metastasize are the current theories explaining these tumors' unpredictable clinical behavior.