Observer variability in the histopathological reporting of core biopsies of papillary breast lesions is reduced by the use of immunohistochemistry for CK5/6, calponin and p63

Clinical Proteomics for Solid Organ Tissues

The evaluation of biopsied solid organ tissue has long relied on visual examination using a microscope. Immunohistochemistry is critical in this process, labeling and detecting cell lineage markers and therapeutic targets. However, while the practice of immunohistochemistry has reshaped diagnostic pathology and facilitated improvements in cancer treatment, it has also been subject to pervasive challenges with respect to standardization and reproducibility. Efforts are ongoing to improve immunohistochemistry, but for some applications, the benefit of such initiatives could be impeded by its reliance on monospecific antibody-protein reagents and limited multiplexing capacity. This perspective surveys the relevant challenges facing traditional immunohistochemistry and describes how mass spectrometry, particularly liquid chromatography-tandem mass spectrometry, could help alleviate problems. In particular, targeted mass spectrometry assays could facilitate measurements of individual proteins or analyte panels, using internal standards for more robust quantification and improved interlaboratory reproducibility. Meanwhile, untargeted mass spectrometry, showcased to date clinically in the form of amyloid typing, is inherently multiplexed, facilitating the detection and crude quantification of 100s to 1000s of proteins in a single analysis. Further, data-independent acquisition has yet to be applied in clinical practice, but offers particular strengths that could appeal to clinical users. Finally, we discuss the guidance that is needed to facilitate broader utilization in clinical environments and achieve standardization.

A multicenter study of interobserver variability in pathologic diagnosis of papillary breast lesions on core needle biopsy with WHO classification

BACKGROUND

Papillary breast lesions (PBLs) comprise diverse entities from benign and atypical lesions to malignant tumors. Although PBLs are characterized by a papillary growth pattern, it is challenging to achieve high diagnostic accuracy and reproducibility. Thus, we investigated the diagnostic reproducibility of PBLs in core needle biopsy (CNB) specimens with World Health Organization (WHO) classification.

METHODS

Diagnostic reproducibility was assessed using interobserver variability (kappa value, κ) and agreement rate in the pathologic diagnosis of 60 PBL cases on CNB among 20 breast pathologists affiliated with 20 medical institutions in Korea. This analysis was performed using hematoxylin and eosin (H&E) staining and immunohistochemical (IHC) staining for cytokeratin 5 (CK5) and p63. The pathologic diagnosis of PBLs was based on WHO classification, which was used to establish simple classifications (4-tier, 3-tier, and 2-tier).

RESULTS

On WHO classification, H&E staining exhibited 'fair agreement' (κ = 0.21) with a 47.0% agreement rate. Simple classifications presented improvement in interobserver variability and agreement rate. IHC staining increased the kappa value and agreement rate in all the classifications. Despite IHC staining, the encapsulated/solid papillary carcinoma (EPC/SPC) subgroup (κ = 0.16) exhibited lower agreement compared to the non-EPC/SPC subgroup (κ = 0.35) with WHO classification, which was similar to the results of any other classification systems.

CONCLUSIONS

Although the use of IHC staining for CK5 and p63 increased the diagnostic agreement of PBLs in CNB specimens, WHO classification exhibited a higher discordance rate compared to any other classifications. Therefore, this result warrants further intensive consensus studies to improve the diagnostic reproducibility of PBLs with WHO classification.

A multicenter study of interobserver variability in pathologic diagnosis of papillary breast lesions on core needle biopsy with WHO classification

Background

Papillary breast lesions (PBLs) comprise diverse entities from benign and atypical lesions to malignant tumors. Although PBLs are characterized by a papillary growth pattern, it is challenging to achieve high diagnostic accuracy and reproducibility. Thus, we investigated the diagnostic reproducibility of PBLs in core needle biopsy (CNB) specimens with World Health Organization (WHO) classification.

Methods

Diagnostic reproducibility was assessed using interobserver variability (kappa value, κ) and agreement rate in the pathologic diagnosis of 60 PBL cases on CNB among 20 breast pathologists affiliated with 20 medical institutions in Korea. This analysis was performed using hematoxylin and eosin (H&E) staining and immunohistochemical (IHC) staining for cytokeratin 5 (CK5) and p63. The pathologic diagnosis of PBLs was based on WHO classification, which was used to establish simple classifications (4-tier, 3-tier, and 2-tier).

Results

On WHO classification, H&E staining exhibited ‘fair agreement’ (κ = 0.21) with a 47.0% agreement rate. Simple classifications presented improvement in interobserver variability and agreement rate. IHC staining increased the kappa value and agreement rate in all the classifications. Despite IHC staining, the encapsulated/solid papillary carcinoma (EPC/SPC) subgroup (κ = 0.16) exhibited lower agreement compared to the non-EPC/SPC subgroup (κ = 0.35) with WHO classification, which was similar to the results of any other classification systems.

Conclusions

Although the use of IHC staining for CK5 and p63 increased the diagnostic agreement of PBLs in CNB specimens, WHO classification exhibited a higher discordance rate compared to any other classifications. Therefore, this result warrants further intensive consensus studies to improve the diagnostic reproducibility of PBLs with WHO classification.

Pathology of breast papillary neoplasms: Community hospital experience

In this study, 550 breast papillary neoplasms collected in a community hospital over more than ten years were reviewed and analyzed. This included 457 intraductal papillomas, 53 papillary carcinomas, 35 papillary DCIS and five invasive papillary carcinomas. The diagnostic rate of papillary neoplasms increased over time, likely due to better recognition by pathologists. Intraductal papillomas occurred most frequently in the upper outer quadrants and contained ADH/DCIS in 19% of cases. A total of 28% of non-incidental papillomas were associated with ADH/DCIS, and 29% of patients with papillomas had ADH/DCIS in adjacent tissue; nearly half of papillomas that were > 1 cm in size contained ADH/DCIS in the papilloma or adjacent to it. No single feature could predict an upgrade on excision for non-atypical intraductal papillomas diagnosed on core biopsy. There was no significant difference in the association of ADH/DCIS with central or peripheral papillomas. The overall upgrade rate of non-atypical intraductal papillomas to DCIS on excision was 2%, which justifies the conservative management of non-atypical sub-centimeter lesions. Papillary carcinomas occurred in older than intraductal papilloma patients and were most frequent in the upper quadrants. Although classically devoid of a myoepithelial cell layer, papillary carcinomas may contain some residual or even an ample myoepithelial cell layer in the papillae. An association between papillary carcinoma and conventional invasive carcinoma was found in 40% of EPCs and 89% of SPCs. Papillary DCIS was usually low- or intermediate-grade. The presence of a myoepithelial cell layer in the papillae was not inconsistent with this diagnosis. Invasive papillary carcinoma may have two histologic patterns: papillary and cribriform.

Diagnosis of Papillary Breast Lesions on Core Needle Biopsy: Upgrade Rates and Interobserver Variability

The histologic distinction between papillary breast lesions remains challenging, especially with core biopsy (CB) specimens. A retrospective review of the clinical, imaging, and histologic findings was performed for patients with papillary breast lesions on CB from 2013 to 2017. The interpretation accuracy was expressed as upgrade rate relative to the excision diagnosis. Diagnostic reproducibility with and without immunohistochemistry was analyzed as interobserver variability among 3 board-certified pathologists. Among 57 papillary lesions with biopsies and excisions available for review, the upgrade rates were 0% for benign papilloma, 30% for papilloma with atypical ductal hyperplasia, and 25% for papilloma with ductal carcinoma in situ, resulting in an overall upgrade rate of 11.1%. There were no statistical differences between patients in an upgrade group and others, when comparing the patient age, clinical presentation, BI-RADS (Breast Imaging Reporting and Database System) category, location, and histologic grade. The overall interobserver variability of the 60 consecutive core biopsies of papillary breast lesions by morphology alone was in the "substantial" agreement range (κ = 0.79, 86% agreement), with an excellent κ score of 0.88 for papilloma (92% agreement). "Substantial" and "fair" κ values were seen for papilloma with atypical ductal hyperplasia/ductal carcinoma in situ (0.74, 84% agreement) and invasive carcinoma (0.40, 60% agreement). Use of immunohistochemical stains improved the κ values into "excellent" range (0.92, 94% agreement). Our study favors a conservative approach in the management of benign papillomas, at least in cases of good radiologic-pathologic concordance. Papillary breast lesions with atypia/malignancy show lower diagnostic reproducibility on CB, and utility of immunohistochemistry is recommended in challenging cases.

Atypical ductal hyperplasia: update on diagnosis, management, and molecular landscape

BACKGROUND

Atypical ductal hyperplasia (ADH) is a common diagnosis in the mammographic era and a significant clinical problem with wide variation in diagnosis and treatment. After a diagnosis of ADH on biopsy a proportion are upgraded to carcinoma upon excision; however, the remainder of patients are overtreated. While ADH is considered a non-obligate precursor of invasive carcinoma, the molecular taxonomy remains unknown.

MAIN TEXT

Although a few studies have revealed some of the key genomic characteristics of ADH, a clear understanding of the molecular changes associated with breast cancer progression has been limited by inadequately powered studies and low resolution methodology. Complicating factors such as family history, and whether the ADH present in a biopsy is an isolated lesion or part of a greater neoplastic process beyond the limited biopsy material, make accurate interpretation of genomic features and their impact on progression to malignancy a challenging task. This article will review the definitions and variable management of the patients diagnosed with ADH as well as the current knowledge of the molecular landscape of ADH and its clonal relationship with ductal carcinoma in situ and invasive carcinoma.

CONCLUSIONS

Molecular data of ADH remain sparse. Large prospective cohorts of pure ADH with clinical follow-up need to be evaluated at DNA, RNA, and protein levels in order to develop biomarkers of progression to carcinoma to guide management decisions.

Characteristics of a Breast Pathology Consultation Practice

CONTEXT

- Intradepartmental consultation is a routine practice commonly used for new diagnoses. Expert interinstitutional case review provides insight into particularly challenging cases.

OBJECTIVE

- To investigate the practice of breast pathology consultation at a large tertiary care center.

DESIGN

- We reviewed breast pathology cases sent for private consultation and internal cases reviewed by multiple pathologists at a tertiary center. Requisitions and reports were evaluated for diagnostic reason for consultation, rate of multiple pathologist review at the tertiary center, use of immunohistochemistry, and, for private consultation cases, type of sender and concordance with the outside diagnosis.

RESULTS

- In the 985 private consultation cases, the most frequent reasons for review were borderline atypia (292 of 878; 33.3%), papillary lesion classification (151 of 878; 17.2%), evaluating invasion (123 of 878; 14%), subtyping carcinoma (75 of 878; 8.5%), and spindle cell (67 of 878; 7.6%) and fibroepithelial (65 of 878; 7.4%) lesion classification. Of 4981 consecutive internal cases, 358 (7.2%) were reviewed, most frequently for borderline atypia (90 of 358; 25.1%), subtyping carcinoma (63 of 358; 17.6%), staging/prognostic features (59 of 358; 16.5%), fibroepithelial lesion classification (45 of 358; 12.6%), evaluating invasion (37 of 358; 10.3%), and papillary (20 of 358; 5.6%) and spindle cell (18 of 358; 5.0%) lesion classification. Of all internal cases, those with a final diagnosis of atypia had a significantly higher rate of review (58 of 241; 24.1%) than those with benign (119 of 2933; 4.1%) or carcinoma (182 of 1807; 10.1%) diagnoses. Immunohistochemistry aided in diagnosis of 39.7% (391 of 985) and 21.2% (76 of 359) of consultation and internally reviewed cases, respectively.

CONCLUSIONS

- This study confirms areas of breast pathology that represent diagnostic challenge and supports that pathologists are appropriately using expert consultation.

Papillary lesions of the breast: impact of breast pathology subspecialization on core biopsy and excision diagnoses

BACKGROUND

Classifying papillary lesions of the breast on core biopsy (CB) is challenging. Although traditionally all such lesions were surgically excised, at present, conservative management of benign lesions is being advocated; therefore, accurately classifying papillary lesions on CB is all the more imperative. The extent to which subspecialty training in breast pathology might mitigate such difficulties in diagnosis has not yet been reported. We investigated change in diagnoses from CB to surgical excision according to subspecialist training in breast pathology and interobserver agreement between specialized breast pathologists (BPs) and nonbreast pathologists (NBPs) in classifying these lesions.

DESIGN

CBs of 281 papillary lesions from 266 patients diagnosed between 2000 and 2010 were classified by both a BP and NBP into benign, atypical, ductal carcinoma in situ/encapsulated papillary carcinoma, or invasive carcinoma categories. Rates of change in diagnostic category in the surgical excision specimen were calculated on the basis of: (i) the original diagnosis, (ii) diagnosis made by the BP, and (iii) diagnosis made by the NBP. Comparisons were made using the χ test. Kappa values were calculated for interobserver agreement.

RESULTS

Of 162 lesions with subsequent excision, 90 were originally diagnosed as benign, 38 as atypical, 25 as ductal carcinoma in situ/encapsulated papillary carcinoma, and 9 as invasive on CB. The upgrade rate for benign papillomas to an atypical or malignant lesion on surgical excision was 22.2% according to the original diagnosis. This rate fell to 16.3% when the BP diagnoses were considered, compared with 26.3% for the NBP diagnoses. There was no significant difference between BPs and NBPs in the rate of upgrade from a benign to an atypical/malignant diagnosis, although downgrades from atypical/malignant to benign papillomas were more commonly seen among NBPs (P=0.002). Overall, the BP diagnosis on CB was less likely to differ from the excision diagnosis (P=0.0001). Benign papillomas upgraded on excision were more likely to occur with larger radiologic mass size (P=0.033) compared with those that were not upgraded. Of 8 benign papillomas upgraded to a malignant lesion on excision, 7 were discordant on radiology. Interobserver agreement between BP and NBP diagnoses was in the "fair agreement" range (κ=0.38), with perfect agreement in 66.4% of cases.

CONCLUSIONS

Correlation between CB and excision diagnoses for breast papillary lesions is significantly greater for BPs than for NBPs. This is largely because of a tendency to overcall atypia or malignancy on CB by NBPs. However, upgrades from benign to atypical or malignant did not significantly differ according to subspecialization. With accurate pathologic assessment and radiologic-pathologic correlation, the upgrade rate of benign papillomas to malignancy can be minimized significantly.

Atypical ductal hyperplasia: interobserver and intraobserver variability

Interobserver reproducibility in the diagnosis of benign intraductal proliferative lesions has been poor. The aims of the study were to investigate the inter- and intraobserver variability and the impact of the addition of an immunostain for high- and low-molecular weight keratins on the variability. Nine pathologists reviewed 81 cases of breast proliferative lesions in three stages and assigned each of the lesions to one of the following three diagnoses: usual ductal hyperplasia, atypical ductal hyperplasia and ductal carcinoma in situ. Hematoxylin and eosin slides and corresponding slides stained with ADH-5 cocktail (cytokeratins (CK) 5, 14. 7, 18 and p63) by immunohistochemistry were evaluated. Concordance was evaluated at each stage of the study. The interobserver agreement among the nine pathologists for diagnosing the 81 proliferative breast lesions was fair (κ-value=0.34). The intraobserver κ-value ranged from 0.56 to 0.88 (moderate to strong). Complete agreement among nine pathologists was achieved in only nine (11%) cases, at least eight agreed in 20 (25%) cases and seven or more agreed in 38 (47%) cases. Following immunohistochemical stain, a significant improvement in the interobserver concordance (overall κ-value=0.50) was observed (P=0.015). There was a significant reduction in the total number of atypical ductal hyperplasia diagnosis made by nine pathologists after the use of ADH-5 immunostain. Atypical ductal hyperplasia still remains a diagnostic dilemma with wide variation in both inter- and intraobserver reproducibility among pathologists. The addition of an immunohistochemical stain led to a significant improvement in the concordance rate. More importantly, there was an 8% decrease in the number of lesions classified as atypical ductal hyperplasia in favor of usual hyperplasia; in clinical practice, this could lead to a decrease in the number of surgeries carried out for intraductal proliferative lesions.

Luminal cytokeratin expression profiles of breast papillomas and papillary carcinomas and the utility of a cytokeratin 5/p63/cytokeratin 8/18 antibody cocktail in their distinction

Luminal cytokeratin (CK) expression in breast papillary lesions, and its potential diagnostic utility among other markers in distinguishing between papillomas and papillary carcinomas, has not been previously evaluated. Such expression was determined in 42 papillary lesions (18 papillary carcinomas and 24 papillomas) by immunostaining with a CK5/p63/CK8/18 antibody cocktail. The mean CK8/18 intensity score and percentage of positive cells were significantly higher in papillary carcinomas (227 and 95%, respectively, vs 86 and 42% in papillomas; both P-values <0.0001), whereas the mean CK5 intensity score and percentage of positive cells were significantly lower (7 and 5%, respectively, vs 107 and 58% in papillomas; both P-values <0.0001). Half (9/18) of the papillary carcinomas expressed p63 vs all (24/24) of the papillomas (P = 0.0001). P63 expression in papillary carcinoma was always (9/9; 100%) focal/limited in nature (expression in <10% of cells), whereas focal expression was seen in only four (17%) papillomas (P<0.0001). Both differential CK (CK8/18 and CK5) expression and p63 were equally sensitive (100%) for the diagnosis of papillary carcinoma, but differential CK expression was more specific (96 vs 83%), resulting in a greater accuracy. However, the best discriminatory power in the distinction from papilloma was achieved when all three markers were used in combination, resulting in 100% sensitivity and specificity values. It is concluded that breast papillary lesions have differential CK expression profiles that, especially in combination with p63, can be useful for their stratification, potentially also in needle biopsy material, in which more accurate and reproducible characterization is needed.

Molecular-assisted immunohistochemical optimization

Immunohistochemistry (IHC) is an essential tool in diagnostic surgical pathology, allowing analysis of protein subcellular localization. The use of IHC by different laboratories has lead to inconsistencies in published literature for several antibodies, due to either interpretative (inter-observer variation) or technical reasons. These disparities have major implications in both clinical and research settings. In this study, we report our experience conducting an IHC optimization of antibodies against five proteins previously identified by proteomic analysis to be breast cancer biomarkers, namely 6PGL (PGLS), CAZ2 (CAPZA2), PA2G4 (EBP1) PSD2 and TKT. Large variations in the immunolocalizations and intensities were observed when manipulating the antigen retrieval method and primary antibody incubation concentration. However, the use of an independent molecular analysis method provided a clear indication in choosing the appropriate biologically and functionally relevant "staining pattern". Without this latter step, each of these contradictory results would have been a priori "technically acceptable" and would have led to different biological and functional interpretations of these proteins and potentially different applications in a routine pathology setting. Thus, we conclude that full validation of immunohistochemical protocols for scientific and clinical use will require the incorporation of biological knowledge of the biomarker and the disease in question.

Diagnostic evaluation of papillary lesions of the breast on core biopsy

The management of asymptomatic intraductal papillary lesions of the breast diagnosed on core biopsy poses a challenge for patients and clinicians, as the distinction between common benign lesions and atypical or malignant varieties may be difficult without formal excision. The aim of this study was to determine whether a combination of histopathologic and biomarker features could be used to accurately identify benign papillary lesions on core biopsy. An inclusive group of 127 excised papillary lesions was characterized by detailed histopathologic review and immunohistochemical staining for the basal markers cytokeratin 5/6 (CK5/6) and P63 and the proliferation marker Ki67. Comparison of benign, atypical, and malignant lesions revealed that the combination of broad, sclerotic fibrovascular cores, and epithelial CK5/6 staining was most commonly seen in benign papillomas. Ki67 staining revealed striking intralesional heterogeneity, but there was no difference between the high scores of benign, atypical, or malignant lesions (P=0.173). In a non-overlapping set of 42 cases, a binary classifier specifying benign lesions on the basis of thick fibrovascular cores and epithelial CK5/6 staining on core biopsy gave an overall misclassification rate of 4/42 (10%) when compared with the final excision diagnosis. Misclassified cases included 2/27 lesions ultimately diagnosed as benign and 2/2 atypical papillomas. All malignant lesions (n=13) were correctly assigned. The combined assessment of fibrovascular core thickness and CK5/6 staining on core biopsy distinguished benign from malignant papillary lesions, but did not separate benign from atypical cases. This approach may form a useful addition to the clinicopathologic evaluation of papillary lesions of the breast.

Cytokeratin 5 and estrogen receptor immunohistochemistry as a useful adjunct in identifying atypical papillary lesions on breast needle core biopsy

The presence of atypical or usual epithelial proliferations within papillary breast lesions complicates their interpretation on core biopsy. We evaluated the combination of estrogen receptor (ER) and cytokeratin 5 (CK5) as an aid in the distinction of usual duct hyperplasia from atypical proliferations in this setting. Core biopsies from 185 papillary lesions were reviewed and of these, 82 cases were selected for immunohistochemical study based on the presence of an epithelial proliferation between the fibrovascular cores. Fifty-two cases were used as the test set and 30 cases, with subsequent surgical excision, were used as the validation set. The epithelial proliferation was evaluated for staining intensity and percentage of positive cells using CK5 and ER. Expression of both CK5 and ER was significantly different in nonatypical lesions when compared with atypical lesions (P<0.0001). Nonatypical lesions typically showed an ER-low/CK5-high profile and atypical lesions showed an ER-high/CK5-low profile with ER-high expression defined as diffuse strong staining in >90% of cells. CK5-high expression was defined as a mosaic pattern of staining in >20% of cells and CK5-low as absent or staining in <20% of cells. On the basis of their staining profile, 29 of the 30 validation cases were correctly classified using the excision specimen as the gold standard. Patterns and extent of ER and CK5 staining, when used together, are valuable adjunct stains to differentiate usual duct hyperplasia from atypical proliferations within papillary lesions on core biopsy.

The role of immunohistochemistry in the differential diagnosis of papillary lesions of the breast

Papillary lesions of the breast represent a heterogeneous group with differing biological behaviour. Correct diagnosis is crucial but may be difficult, as many benign and malignant papillary lesions have similar appearances. Immunohistochemistry plays a useful role in their differentiation. Myoepithelial markers can help in differentiating papilloma from papillary carcinoma, as the former usually shows a continuous layer of myoepithelial cells. In intracystic papillary carcinoma, there is controversy as to the presence of a complete myoepithelial cell layer around these lesions. p63 is the marker of choice as the staining is nuclear, cross-reactivity is minimal, and sensitivity is high. Papilloma may frequently be complicated by superimposed different types of epithelial hyperplasia, which range from usual to atypical or even ductal carcinoma in situ, and they many be morphologically similar. Basal cytokeratins (CKs) are useful to differentiate these entities; as usual hyperplasia is positive for basal CKs with a mosaic staining pattern. CK5/6 is probably the best marker. Neuroendocrine markers (chromogranin A and synaptophysin) may be positive in papillary carcinoma, particularly in the solid type, and there may be some overlap with the ductal carcinoma in situ with spindle cells or endocrine ductal carcinoma in situ. A panel of CK5/6, p63 and neuroendocrine markers can be useful in the diagnostic investigation of problematic papillary lesions of the breast. As the experience with these markers remains rather limited, it is too early to recommend basing treatment choices on these marker studies alone. Complete removal of lesion is probably still the treatment of choice.

Are complex carcinoma of the feline mammary gland and other invasive mammary carcinoma identical tumours? Comparison of clinicopathologic features, DNA ploidy and follow up

Feline mammary carcinomas are known for their unfavourable prognosis due to a strong tendency to local recurrence and metastasis. We studied 73 spontaneous primary mammary carcinomas and identified eight cases presenting a biphasic nature, with neoplastic epithelial and myoepithelial cells (complex carcinoma). These cases presented histopathologic features associated with a better prognosis; they were also associated with higher overall survival and disease-free survival rates compared to other common invasive mammary carcinomas of non-specified type. Complex carcinoma appears to be a low-grade malignancy.

The Role of Cytokeratin 5/6 as an Adjunct Diagnostic Tool in Breast Core Needle Biopsies

In this article, the probability of finding malignancy on surgical excision after applying well-defined morphological criteria combined with immunohistochemical evaluation of cytokeratin 5/6 for the diagnosis of atypical ductal hyperplasia on core biopsies is examined. On the basis of morphology alone, the reviewers reclassified the diagnoses of 140 core biopsies as follows: atypical ductal hyperplasia (n = 64), ductal hyperplasia of usual type (n = 44), flat epithelial atypia (n = 11), and miscellaneous benign (n = 21). Cytokeratin 5/6 immunostain was negative in 85.7% of atypical ductal hyperplasia cases and positive in 77.8% of ductal hyperplasia of usual type cases. The probability of predicting malignancy in a surgical specimen following a core biopsy increased from 43.6% to 67.8% ( P = .002) by adhering to defined criteria and using cytokeratin 5/6 immunostain. Expertise and adherence to defined criteria are required to establish an accurate diagnosis of atypical ductal hyperplasia. Cytokeratin 5/6 can be a useful adjunct in cases with ductal hyperplasia but not in columnar cell lesions, where it is universally negative.

MRI for diagnosis of pure ductal carcinoma in situ: a prospective observational study

BACKGROUND

Diagnosing breast cancer in its intraductal stage might be helpful to prevent the development of invasive cancer. Our aim was to investigate the sensitivity with which ductal carcinoma in situ (DCIS) is diagnosed by mammography and by breast MRI.

METHODS

During a 5-year period, 7319 women who were referred to an academic national breast centre received MRI in addition to mammography for diagnostic assessment and screening. Mammograms and breast MRI studies were assessed independently by different radiologists. We investigated the sensitivity of each method of detection and compared the biological profiles of mammography-diagnosed DCIS versus DCIS detected by MRI alone. We also compared the risk profiles of women with mammography-detected DCIS with those of MRI-detected DCIS.

FINDINGS

193 women received a final surgical pathology diagnosis of pure DCIS. Of those, 167 had undergone both imaging tests preoperatively. 93 (56%) of these cases were diagnosed by mammography and 153 (92%) by MRI (p<0.0001). Of the 89 high-grade DCIS, 43 (48%) were missed by mammography, but diagnosed by MRI alone; all 43 cases missed by mammography were detected by MRI. By contrast, MRI detected 87 (98%) of these lesions; the two cases missed by MRI were detected by mammography. Age, menopausal status, personal or family history of breast cancer or of benign breast disease, and breast density of women with MRI-only diagnosed DCIS did not differ significantly from those of women with mammography-diagnosed DCIS.

INTERPRETATION

MRI could help improve the ability to diagnose DCIS, especially DCIS with high nuclear grade.

The management of papillary breast lesions on core biopsy: the contentious issues

The management of papillary lesions of the breast diagnosed on core needle biopsy is highly contentious. Papillary lesions are epithelial proliferations of breast tissue and are on a continuum of mutations with atypical hyperplastic lesions and in situ carcinoma. With the current literature suggesting that excisional biopsy of papillary lesions might not be required, we discuss a unique case that suggests otherwise. We present a 21-year-old woman with multiple papillary lesions on core biopsy of a breast lesion, and a subsequent excisional biopsy revealing extensive in situ carcinoma of the breast. This finding necessitated total mastectomy. This unique case highlights that core biopsy specimens are unable to effectively exclude adjacent in situ carcinoma and suggests that papillary lesions diagnosed on core needle biopsy require excisional biopsy.

Myoepithelial cells in solid variant of intraductal papillary carcinoma of the breast: a potential diagnostic pitfall and a proposal of an immunohistochemical panel in the differential diagnosis with intraductal papilloma with usual ductal hyperplasia

We examined myoepithelial status in intraductal papillary carcinoma (IPC) along with the expression of high-molecular weight cytokeratin (HMWK) and neuroendocrine markers, with special reference to the differential diagnosis of solid intraductal papillary carcinoma(SIPC) and intraductal papilloma with usual ductal hyperplasia (IP-UDH). Twenty-six (93%) of the twenty-eight intraductal papillomas (IP) had myoepithelial cells in >70% of the epithelial-stromal interface of the intraluminal proliferating component. Six (29%) of twenty-one SIPC had almost complete myoepithelial layer like IP-UDH at the epithelial-stromal interface. HMWK (34 beta E-12) was diffusely positive in 14 (93%) of 15 IP-UDH, but 16 (76%) of 21 SIPC were completely negative for HMWK. Neuroendocrine markers were positive in 14 (67%) of SIPC, but all 28 IPs were completely negative. If only the presence of myoepithelial cells is emphasized as a benign hallmark, about 30% of SIPCs may be underdiagnosed as IP-UDH. However, by using a combination of myoepithelial markers, HMWK, and neuroendocrine markers, all of the 36 solid intraductal papillary lesions were properly classified as benign and malignant. Solid intraductal papillary lesions meeting at least two of the following criteria are highly likely to be malignant: (1) absence of myoepithelial cells(<10% of epithelial-stromal interface of intraluminal proliferating component), (2) negative HMWK(<10%), (3) positive neuroendocrine markers (>10%).

The value of p63 and CK5/6 expression in the differential diagnosis of ductal lesions of breast

In order to explore the value of p63, smoothmuscle actin (alpha-SMA) and cytokeratin 5/6 (CK5/6) in the differential diagnosis of ductal lesions of breast, 88 tissue specimens of ductal lesions of breast were collected and examined histologically by HE staining. By using immunohistochemistry, the expression of p63, alpha-SMA and CK5/6 was detected. The results showed that in 38 cases of benign breast lesions, the proliferating cells were all positive for p63 and alpha-SMA. In 19 cases of ductal carcinoma in situ (DCIS) and 7 cases of intraductal papillary carcinoma, alpha-SMA positive cells formed a layer of continuous embroider-shaped structure and the p63 positive cells formed a layer of evenly separated embroider-shaped structure around the ducts. There was no cross-reaction between p63 and interstitial myofibroblasts and vascular smooth muscle cells. In 38 cases of benign breast lesions, the positive rate of CK5/6 expression was 100%. In 5 cases of atypical ductal hyperplasia, there were few positive cells in the ducts. In 19 cases of CDIS, no tumor cells expressed CK5/6. In 19 cases of invasive ductal carcinoma, almost no CK5/6 was detectable. It was suggested that p63 could serve as a novel specific marker for the identification of breast myoepithelial cells. CK5/6 is of value in differentiating ductal proliferation of varying degrees, especially in the differentiation between cancerous and non-cancerous changes. Simultaneous detection of p63, CK5/6 and alpha-SMA can help increase the diagnostic accuracy of breast diseases.