A Diagnostic Approach to Fibroepithelial Breast Lesions

Evaluation of the precision and accuracy in the classification of breast histopathology images using the MobileNetV3 model

Accurate surgical pathological assessment of breast biopsies is essential to the proper management of breast lesions. Identifying histological features, such as nuclear pleomorphism, increased mitotic activity, cellular atypia, patterns of architectural disruption, as well as invasion through basement membranes into surrounding stroma and normal structures, including invasion of vascular and lymphatic spaces, help to classify lesions as malignant. This visual assessment is repeated on numerous slides taken at various sections through the resected tumor, each at different magnifications. Computer vision models have been proposed to assist human pathologists in classification tasks such as these. Using MobileNetV3, a convolutional architecture designed to achieve high accuracy with a compact parameter footprint, we attempted to classify breast cancer images in the BreakHis_v1 breast pathology dataset to determine the performance of this model out-of-the-box. Using transfer learning to take advantage of ImageNet embeddings without special feature extraction, we were able to correctly classify histopathology images broadly as benign or malignant with 0.98 precision, 0.97 recall, and an F1 score of 0.98. The ability to classify into histological subcategories was varied, with the greatest success being with classifying ductal carcinoma (accuracy 0.95), and the lowest success being with lobular carcinoma (accuracy 0.59). Multiclass ROC assessment of performance as a multiclass classifier yielded AUC values ≥0.97 in both benign and malignant subsets. In comparison with previous efforts, using older and larger convolutional network architectures with feature extraction pre-processing, our work highlights that modern, resource-efficient architectures can classify histopathological images with accuracy that at least matches that of previous efforts, without the need for labor-intensive feature extraction protocols. Suggestions to further refine the model are discussed.

Diagnostic Pitfalls in Breast Cancer Pathology With an Emphasis on Core Needle Biopsy Specimens

CONTEXT.—

Breast pathology has many mimics and diagnostic pitfalls. Evaluation of malignant breast lesions, particularly in the biopsy setting, can be especially challenging, with diagnostic errors having significant management implications.

OBJECTIVE.—

To discuss the pitfalls encountered when evaluating ductal carcinoma in situ and invasive breast carcinomas, providing histologic clues and guidance for appropriate use and interpretation of immunohistochemistry to aid in the correct diagnosis.

DATA SOURCES.—

Data were obtained from review of pertinent literature of ductal carcinoma in situ and invasive breast carcinomas and from the experience of the authors as practicing breast pathologists.

CONCLUSIONS.—

Awareness of the pitfalls in diagnosing breast cancers is important when creating a differential diagnosis for each breast lesion evaluated. This review will cover some of these scenarios to aid in the diagnostic process.

Breast development and disorders in children and adolescents

Breast masses are infrequently encountered in pediatric and adolescent populations. Most breast masses in children are benign entities arising from embryological defects which can be managed once breast development is complete. Diagnostic and management dilemmas arise when fibroepithelial lesions of the breast are seen in clinical practice. Differentiation between a fibroadenoma and a phyllodes tumor is important to guide management. Breast cancer in children under 18 years of age is extremely rare and invasive diagnostic testing and aggressive management is only recommended when clinical suspicion of malignancy is very high. Patient and caregiver counseling plays an important role in the management of these diseases. While adult-onset breast diseases have been studied very closely, there is a dearth of literature on pediatric breast anomalies. This review aims to provide a scoping overview of the available literature on benign, fibroepithelial, and malignant lesions of the breast in pediatric and adolescent populations to help guide physicians and surgeons with decision-making regarding the diagnosis and management of pediatric breast diseases.

Fibroepithelial Lesion Spectrum: A Case Report Documenting a Possible Transformation to a Malignant Phyllodes Tumor

We discuss the radiological-pathological aspects of a rare case of transformation of a presumed fibroadenoma (FA) to a malignant phyllodes tumor (PT) and review the literature. Phyllodes tumors often show heterogeneous histologic features with some areas indistinguishable on core needle biopsy. A core biopsy is often a small representation of a larger lesion. As such, a complete excisional biopsy is often needed for a definitive pathologic diagnosis. Careful clinical and imaging correlation and follow-up are necessary, even in a benign fibroepithelial lesion (FEL).

Phyllodes tumour evidence gaps mapped from the 5th edition of the WHO classification of tumours of the breast

AIMS

Breast phyllodes tumours (PTs) are a rare subset of fibroepithelial neoplasms categorised into benign, borderline, and malignant grades according to the World Health Organization (WHO) Classification of Tumours (WCTs). In this report, we developed an evidence gap map (EGM) based on the literature cited in the PT chapter of the 5th edition of the breast WCT in order to identify knowledge and research gaps in PT.

METHODS

A framework was first established where the dimensions of the EGM were defined as categories of tumour descriptors, tumour types, and evidence levels. Citations were collected into a Microsoft Excel form and imported into EPPI-reviewer to produce the EGM.

RESULTS

The EGM showed that the "Histopathology" and "Pathogenesis" sections contained the most citations, the majority being of low-level evidence. The highest number of citations considered of moderate-level evidence were found in the "Histopathology" section. There was no high-level evidence cited in this chapter. The "Localisation", "Aetiology", and "Staging" sections had the fewest citations.

CONCLUSION

This EGM provides a visual representation of the cited literature in the PT chapter of the breast WCT, revealing the lack of high-level evidence citations. There is an uneven distribution of references, probably due to citation practices. Pockets of low-level evidence are highlighted, possibly related to referencing habits, lack of relevant research, or the belief that the information presented is standard accepted fact, without the need for specific citations. Future work needs to bridge evidence gaps and broaden citations beyond those in the latest WCT.

Current clinical practice in the management of phyllodes tumors of the breast: an international cross-sectional study among surgeons and oncologists

PURPOSE

Phyllodes tumors of the breast are rare fibroepithelial lesions that are classified as benign, borderline or malignant. There is little consensus on best practice for the work-up, management, and follow-up of patients with phyllodes tumors of the breast, and evidence-based guidelines are lacking.

METHODS

We conducted a cross-sectional survey of surgeons and oncologists with the aim to describe current clinical practice in the management of phyllodes tumors. The survey was constructed in REDCap and distributed between July 2021 and February 2022 through international collaborators in sixteen countries across four continents.

RESULTS

A total of 419 responses were collected and analyzed. The majority of respondents were experienced and worked in a university hospital. Most agreed to recommend a tumor-free excision margin for benign tumors, increasing margins for borderline and malignant tumors. The multidisciplinary team meeting plays a major role in the treatment plan and follow-up. The vast majority did not consider axillary surgery. There were mixed opinions on adjuvant treatment, with a trend towards more liberal regiments in patients with locally advanced tumors. Most respondents preferred a five-year follow-up period for all phyllodes tumor types.

CONCLUSIONS

This study shows considerable variation in clinical practice managing phyllodes tumors. This suggests the potential for overtreatment of many patients and the need for education and further research targeting appropriate surgical margins, follow-up time and a multidisciplinary approach. There is a need to develop guidelines that recognize the heterogeneity of phyllodes tumors.

Fibroepithelial Lesions of the Breast: Update on Molecular Profile With Focus on Pediatric Population

CONTEXT.—

This review article derives from the breast pathology lecture at the Eighth Princeton Integrated Pathology Symposium (PIPS VIII).

OBJECTIVE.—

To provide a literature review and update on fibroepithelial lesions of the breast with molecular findings and findings regarding the pediatric population.

DATA SOURCES.—

The sources include extensive literature review, personal research, and experience.

CONCLUSIONS.—

Given significant differences in prognosis and management of fibroepithelial lesions, we aim to provide readers with pertinent definitions, pathomorphology, molecular findings, and management for each diagnosis, with insights on the pediatric population.

Survey of recurrent diagnostic challenges in breast phyllodes tumours

BACKGROUND

Breast phyllodes tumours (PTs) are graded as benign, borderline, or malignant by analysis of multiple histological features. PT grading is often inconsistent, likely due to variation in the weighting of grading criteria by pathologists.

DESIGN

The hierarchy of use of diagnostic criteria was identified using a 20-question survey.

RESULTS

In all, 213 pathologists from 29 countries responded. 54% reported 10-50 PT cases per year. Criteria considered key to PT diagnosis were: increased stromal cellularity (84.3%), stromal overgrowth (76.6%), increased stromal mitoses (67.8%), stromal atypia (61.5%), stromal fronding (59.0%), periductal stromal condensation (58.0%), irregular tumour borders (46.3%), and/or lesional heterogeneity (33.7%). The importance of grading parameters were: mitotic activity (55.5%), stromal overgrowth (54.0%), stromal atypia (51.9%), increased stromal cellularity (41.7%), and nature of the tumour border (38.9%). 49% would diagnose malignant PT without a full array of adverse features. 89% used the term "cellular fibroepithelial lesion (FEL)" for difficult cases; 45% would diagnose an FEL with stromal fronding (but lacking other PT features) as fibroadenoma (FA), 35% FEL, and 17% PT. 59% deemed clinico-radiological findings diagnostically significant; 68% considered age (≥40 years) important in determining if an FEL was a FA or PT. In FELs from young patients, increased stromal cellularity (83%), fronding (52%), and mitoses (41%) were more common. 34% regarded differentiating cellular FA from PT as a specific challenge; 54% had issues assigning a borderline PT grade.

CONCLUSION

Criteria for grading PT lie on a spectrum, leading to interpretive variability. The survey highlights the criteria most used by pathologists, which do not completely align with WHO recommendations.

Prevalence of breast fibroadenoma in healthy physical examination population in Guangdong province of China: a cross-sectional study

OBJECTIVE

To provide an accurate assessment of the prevalence of breast fibroadenoma in a large population and to confirm the diagnostic accuracy of ultrasound for fibroadenoma.

DESIGN

This was a cross-sectional survey.

SETTING

This research was conducted at Nanfang Hospital, Guangzhou, Guangdong, China.

PARTICIPANTS

A total of 11 898 women aged 18-40 years who underwent breast screening between 1 January 2019 and 31 December 2019 were included in the fibroadenoma prevalence study. From 1 June 2019 to 31 December 2019, 342 breast lesions with pathology reports and preoperative ultrasound images were collected for diagnostic fibroadenoma testing (vs histological diagnostic testing).

PRIMARY OUTCOME MEASURES

Pearson's χ² test was performed to compare the prevalence of different lesions between age groups, and descriptive statistics were used to report the clinical characteristics of fibroadenoma. For ultrasound diagnosis, fibroadenoma was defined as a well-circumscribed lesion with round or oval shape, consisting of a homogeneously hypoechoic or isoechoic solid mass, located parallel to the chest wall with a smooth margin and no posterior shadowing. Diagnostic test results for breast fibroadenoma were stratified by diagnostic type (histological vs ultrasound).

RESULTS

Of the women aged 18-40 years, 27.6% (3285/11 898) had an ultrasound diagnosis offibroadenoma. Of these, the prevalence of fibroadenoma was stable across age groups (p=0.14) and did not differ between the left and right sides of the breast. Almost two-thirds of women presented with a single fibroadenoma, and most fibroadenomas did not exceed 1 cm in size. The sensitivity and specificity for fibroadenoma were 97.0% (95% CI for sensitivity: 93.7% to 98.8%) and 91.4% (95% CI for specificity: 85.4% to 95.5%) for ultrasonography, respectively.

CONCLUSIONS

The prevalence of fibroadenoma in South China is as high as 27.6%, and ultrasound could be used as a tool to diagnose fibroadenoma.

Prognostic Significance of Three-Tiered World Health Organization Classification of Phyllodes Tumor and Correlation to Singapore General Hospital Nomogram

OBJECTIVES

Phyllodes tumors (PTs) are categorized by the World Health Organization (WHO) as benign, borderline, and malignant. Singapore General Hospital (SGH) nomogram is a recurrence risk assessment tool for PT, which uses cytologic atypia, mitosis, stromal overgrowth, and the surgical margin status. We studied the prognostic significance of WHO classification and its correlation to the SGH nomogram.

METHODS

We identified 270 consecutive cases of PT (195 benign, 49 borderline, 26 malignant). Follow-up was available on 246 cases (mean follow-up of 51 months).

RESULTS

The recurrence rates were 2% (4 of 176) for benign, 4% (2 of 46) for borderline, and 25% (6 of 24) for malignant (log-rank test P < .0001 for recurrence-free survival). Only five patients with malignant PT experienced distant recurrence. Stromal overgrowth was an independent predictor of recurrence-free survival on multivariable analysis. The mean nomogram scores for benign, borderline, and malignant PT were 20, 20.3, and 32, respectively. The higher than expected score for benign PT was due to positive margins in 39% of cases.

CONCLUSIONS

The WHO three-tiered classification of PT is prognostic. Despite positive margin status, most benign PTs do not recur. Other features of the nomogram help in determining recurrence but are also used for WHO classification.

Preoperative embolization of a giant benign phyllodes tumor: A case report and review of literature

INTRODUCTION AND IMPORTANCE

Phyllodes tumors (PT) account for less than 1% of all breast tumors. Giant PTs can lead to breast disfigurement, tumoral ulceration, and bleeding. Outright surgical excision can be challenging or unsafe. Preoperative transarterial embolization (TAE) has a role but data on its use in the management of PT is limited.

CASE PRESENTATION

A 43-year-old female presented with a 28 cm fungating, necrotic, benign PT on her left breast that eventually developed tumoral bleeding leading to hemodynamic instability. Preoperative TAE controlled the bleeding and allowed the safe performance of mastectomy. A literature review of preoperative TAE of PTs is also presented including the addition of a chemotherapeutic agent in malignant types.

CLINICAL DISCUSSION

PTs are rare and comprise only 2.5% of all fibroepithelial breast lesions. Tumoral bleeding causing severe anemia is one of the most common presentations of massive (≥20 cm) PTs, especially when neglected. Indications for preoperative TAE include (1) to halt rapid tumor growth, (2) to control active/persistent tumoral bleeding, and (3) to shrink the tumor size and allow successful resection with negative margins, and avoidance of skin grafting. Post-TAE side effects include fever, chest pain, gradual/expanding tumor necrosis, decrease in tumor weight, and diminished tumoral abscess/discharge, and loss of tumoral vessel elasticity.

CONCLUSION

Neglected PTs can reach an alarming size. Preoperative TAE is a safe and effective method of controlling life-threatening tumoral hemorrhage and decreasing the size of PTs thereby allowing definitive resection while avoiding skin grafting and/or flap reconstruction.

Diagnosis on Excision Biopsy of Breast Tissues Labeled As Fibroepithelial Tumors on Trucut Samples in a Developing Country

Introduction: Fibroadenomas (FAs) and phyllodes tumors (PTs) are less prevalent but allied to have malignant transformation in many instances. It is a challenge to diagnose the phyllodes by conventional trucut biopsy technique.

Objective: To evaluate the histological characteristics of tumors labeled as fibroepithelial lesions of breast tissues on trucut biopsy and compare with a diagnosis on excision biopsy.

Methods and materials: It was a descriptive cross-sectional study that was carried out in Shaukat Khanum Memorial Hospital and Research Centre within six years from January 2015 to January 2021. In trucut samples, stromal cellularity, stromal cell nuclear atypia, mitotic count, stromal overgrowth, the enhancement of stromal cellularity adjacent to epithelium were scrutinized. In each category, the activity was seen as absent, mild, moderate, or severe. Mitotic activity was graded as 0-1, 0-5, 5-10, >10.

Results: A total of 125 patients were registered for the study. The mean age of patients in our study was 33.86 ± 9.95 years. The mean size was 41.02 ± 27.38 mm with a mean lump duration of 7.52 ± 5.34 months. In the FA group, the trucut sampling report showed the stromal cellularity as mild in 62 (69.7%) and stromal cell nuclear atypia as absent in 68 (76.4%) cases. But in the phyllodes tumor group, the stromal cellularity was severe in 10 (27.8%) patients and stromal cell nuclear atypia was severe in five (13.9%). The ultimate outcome showed that 89 (71.2%) patients had FA and 36 (28.8%) had PT at excision.

Conclusion: Assessment of tumor size, stromal cellularity, mitoses, and enhancement of stromal cellularity adjacent to epithelium are useful markers for diagnosing the PT in trucut needle biopsy.

Clinicopathologic Characteristics and Patient Outcomes of Phyllodes Tumors: A Single Institution Experience

Phyllodes tumors (PT) are rare fibroepithelial neoplasms that are classified as benign, borderline, or malignant. Patients with PT diagnosed between 2009 and 2019 were identified from a prospectively maintained single institutional database. 76 patients with PT were included; 47 (61.8%) were benign, 9 (11.8%) were borderline, and 20 (26.3%) were malignant. The mean age at diagnosis was 52. Surgical treatment of benign PT included excisional biopsy in 31 (66.0%) patients, segmental mastectomy in 15 (31.9%), and mastectomy in 1 (2.1%). Among patients with borderline PT, operative management was excisional biopsy in 4 (44.4%) and segmental mastectomy in 5 (55.6%). Of those with malignant PT, 7 (35.0%) were treated with excisional biopsy alone, 9 (45.0%) had lumpectomy (segmental mastectomy), and 4 (20.0%) underwent mastectomy. Malignant PT had a higher rate of necrosis compared to borderline or benign PT (25.0% vs 0% vs 4.3%, P = .016). Four patients had recurrent PT. Final positive margins were associated with recurrence (P = .044). The median overall follow-up time was 86.3 months (range 1.5-1414.1 months), and no deaths occurred among patients with malignant PT. Overall, recurrence rates of PT are low but may be increased by presence of positive margins.

Upstaging of Fibroepithelial Lesions: A Single-Institution Experience

INTRODUCTION

Fibroepithelial lesions of the breast (FEL) are heterogeneous lesions ranging from fibroadenomas (FA) to phyllodes tumors (PT). FEL with cellular stroma are diagnostic challenges on core needle biopsy (CNB) as it is difficult to distinguish cellular FA from PT. The purpose of this study was to determine the features of FEL on CNB that may be predictive of PT, the upstage rate to PT after excision, and the outcomes of those who did not undergo excision.

METHODS

Overall, 305 patients with FEL on CNB between 2009 and 2019 were identified from a prospectively maintained institutional database. Presentation, imaging, and pathology were evaluated.

RESULTS

Mean age at diagnosis was 43.8 years. Pathology on CNB included 97 cases of FEL favoring FA, 19 cases of FEL favoring PT, 3 cases of FEL versus pseudoangiomatous stromal hyperplasia, and 186 cases of FEL not otherwise specified. Following CNB, 96 (31.5%) patients were observed, 158 (51.8%) patients had an excisional biopsy, 48 (15.7%) patients underwent segmental mastectomy, and 3 (1.0%) patients underwent a mastectomy. The upgrade rate from FEL on CNB to PT upon excision was 25.8%. PT on final pathology was more commonly seen when the CNB identified stromal overgrowth, necrosis, and diagnosis of FEL favoring PT. On multivariable analysis, a final diagnosis of PT was associated with age >50 years, larger tumor size >2 cm, stromal overgrowth, and ≥1 mitoses/10 high power fields (HPF) on CNB. Patients who were observed had smaller tumors compared with those who underwent excision.

CONCLUSION

In this 10-year single-institution experience of FEL, the upstage rate to PT was 25.8%. Excision of FEL is recommended. Furthermore, the observation of lesions appeared to be safe in select cases, specifically in patients with smaller tumor size.

Benign myofibroblastic/epithelial lesions of the breast with minimally infiltrative margins

A minority of mixed fibro-epithelial lesions of the breast lacks both fibroadenoma and phyllodes architectural patterns and have been previously labeled with different terms, including "hamartomas", "myoid/muscular hamartomas", "benign fibroadenomatous lesions" or "stromo-epithelial lesions of the breast". This study emphasizes the clinico-pathologic features of 5 cases of mammary benign fibro(stromo)-epithelial lesions sharing as a common morphologic theme the presence of minimally infiltrative margins due to the overgrowth of the stromal component into the surrounding fibro-fatty tissue. Notably the radiological features were suspicious for malignancy in 3 out of 5 cases. The following histologic features were seen in all cases: i) an epithelial component of benign glandular structures exhibiting the morphological spectrum of fibro-cystic disease; ii) a stromal component of bland-looking spindle cell myofibroblasts (vimentin + and α-smooth muscle actin +) set in a variably fibro-myxoid stroma. The present paper contributes to widen the morphological spectrum of the benign fibro-epithelial lesions of the breast, emphasizing the possibility that some cases, exhibiting a predominant myofibroblastic stromal component and minimally infiltrative margins, may be confused with other primary spindle cell mimickers of the breast. Accordingly, we propose the descriptive term "benign myofibroblastic/epithelial lesions of the breast with minimally infiltrative margins" for these previously underrecognized lesions.

Prognostic factors in phyllodes tumours of the breast: retrospective study on 166 consecutive cases

BACKGROUND

Phyllodes tumours (PTs) are rare fibroepithelial tumours accounting for <1% of all breast tumours. We assessed clinicopathological features and their prognostic effect in a single-institution patients' cohort.

METHODS

Patients diagnosed with PT between 2001 and 2018 at our institution were identified. Clinical, surgical and pathological features were collected. Phyllodes-related relapse was defined as locoregional or distant recurrence (contralateral excluded), whichever first.

RESULTS

A total of 166 patients were included: 115 with benign, 30 with borderline and 21 with malignant PTs. Features associated with malignant PT were younger age, larger T size, higher mitotic count, marked cytological atypia, stromal overgrowth, stromal hypercellularity, necrosis and heterologous differentiation (all p<0.01). The majority of patients with malignant PT underwent mastectomy (63.2% vs 3% of benign/borderline, p<0.001) and had negative surgical margins (83.3%). 4-year cumulative phyllodes-related relapse incidence was 7% for benign/borderline PT and 21.3% for malignant PT (p=0.107). In the entire cohort, marked cellular atypia and heterologous differentiation were associated with worse phyllodes-related relapse-free survival (HR 14.10, p=0.036 for marked vs mild atypia; HR 4.21, p=0.031 for heterologous differentiation present vs absent). For patients with benign PT, larger tumour size was associated with worse phyllodes-related relapse-free survival (HR 9.67, p=0.013 for T>5 cm vs T≤2 cm). Higher tumour-infiltrating lymphocytes (TILs) were associated with borderline and malignant PT (p=0.023); TILs were not associated with phyllodes-related relapse-free survival (HR 0.58, p=0.361 for TILs>2% vs≤2%). Overall, four patients died because of PT: three patients with malignant and one with borderline PT.

CONCLUSIONS

Patients with malignant PT had increased rates of phyllodes-related relapse and phyllodes-related death. Cellular atypia and heterologous differentiation were poor prognostic factors in the entire cohort; large tumour size was associated with an increased risk of phyllodes-related relapse in benign PT.

CD117/c-KIT Expression in Phyllodes Tumor of the Breast and Its Correlation With Morphology and Clinical Outcome

Introduction

Breast phyllodes tumor’s (PT) clinical behavior is difficult to predict on histology. There is limited amount of data available on the role of biological markers. The objective of this study was to assess the expression of CD117 (c-KIT) in PT of the breast and its relationship with morphology and clinical outcome.

Methods

A total of 78 patients having available clinical records between 2004 and 2014 with breast PT were retrieved from the cancer registry at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore and were followed up. Immunohistochemical studies were performed on all the cases using mono­clonal antibody CD117 (DAKO A4502) using Leica Bond-Max automated biosystem (Leica Biosystems, Melbourne, Australia). Staining proportion and intensity of both epithelial and stromal elements were analyzed. Evaluation of the protein expression was determined and scored.

Results

Patients’ mean age was 45.13 ± 11.4 years. Thirty-nine (50.0%) patients had tumor on right side, 38 (48.7%) had on left and only one (1.3%) was bilateral. Thirty-two (41.0%) patients had benign PT, 21 (26.9%) had borderline and 25 (32.1%) had malignant PT. Negative CD117 expression was observed in 20 (62.5%), eight (38.0%) and 12 (48.0%) of benign, borderline and malignant PTs, respectively. Positive CD117 expression was observed in 12 (37.5%) benign, 13 (61.9%) borderline and 13 (52.0%) malignant PTs. There was insignificant association between CD117 expression with respect to tumor sub-type, patient’s age and clinical behavior (p-value > 0.05).

Conclusion

CD117 expression was not found to be associated with tumor type and was not associated with increased risk of recurrence in this sample of patients. Further work is needed to better understand the prognostic value of CD117 expression in breast PTs.

Epithelial-mesenchymal transition and cancer stem cell interactions in breast phyllodes tumours: immunohistochemical evaluation of EZH2, EZR, HMGA2, CD24 and CD44 in correlation with outcome analysis

AIM

Phyllodes tumours (PTs) categorised as benign, borderline and malignant, account for 1% of all breast tumours. Histological assessment does not always predict tumour behaviour, hindering determination of the clinical course and management.Epithelial-mesenchymal transition (EMT) is an important process during embryogenesis. Dysregulation of EMT causes loss of cell polarity, decreased intercellular adhesion, increased motility and invasiveness, promoting tumour progression. Similarly, cancer stem cells (CSCs) promote tumour growth, resistance and recurrence. The aim of this study is to evaluate expression of CSC markers; enhancer of zeste homolog 2 (EZH2), CD24 and CD44 and EMT associated proteins; ezrin (EZR) and high-mobility group AT-hook 2 (HMGA2) in PTs.

METHOD

Uing tissue microarray sections, immunohistochemistry was performed on 360 PTs. Epithelial and stromal expressions of EZH2, EZR, HMGA2, CD24 and CD44 were evaluated to assess their impact on disease progression and behaviour in correlation with clinicopathological parameters.

RESULTS

Stromal expression of EZH2, EZR and HMGA2 was observed in 73 (20.3%), 53 (14.7%) and 28 (7.8%) of tumours, epithelial expression in 121 (35.9%), 3 (0.8%) and 351 (97.5%) tumours, respectively. CD24 and CD44 staining was absent in both components.

CONCLUSION

Expression of biomarkers correlated significantly with aggressive tumour traits such as stromal hypercellularity, atypia, mitoses and permeative tumour borders.Stromal expression of EZH2 and EZR shortened disease-free survival and overall survival; HMGA2 expression did not alter patient survival. EZH2 and EZR may thus be useful in predicting PT behaviour.

Fibroepithelial lesions revisited: implications for diagnosis and management

Fibroepithelial lesions of the breast, comprising the fibroadenoma and phyllodes tumour, are a unique group of neoplasms that share histological characteristics but possess different clinical behaviour. The fibroadenoma is the commonest benign breast tumour in women, while the phyllodes tumour is rare and may be associated with recurrences, grade progression and even metastasis. The diagnosis of fibroadenoma is usually straightforward, with recognised histological variants such as the cellular, complex, juvenile and myxoid forms. The phyllodes tumour comprises benign, borderline and malignant varieties, graded using a constellation of histological parameters based on stromal characteristics of hypercellularity, atypia, mitoses, overgrowth and the nature of tumour borders. While phyllodes tumour grade correlates with clinical behaviour, interobserver variability in assessing multiple parameters that are potentially of different biological weightage leads to significant challenges in accurate grade determination and consequently therapy. Differential diagnostic considerations along the spectrum of fibroepithelial tumours can be problematic in routine practice. Recent discoveries of the molecular underpinnings of these tumours may have diagnostic, prognostic and therapeutic implications.

Fibroepithelial Lesion Initially Believed to Be Fibroadenoma, but Interval Growth Consistent With Phyllodes Tumor

Fibroepithelial lesions of the breast are commonly encountered tumors comprised of stromal and epithelial components. Fibroadenoma and phyllodes tumor are both fibroepithelial lesions, but their management differs. Phyllodes tumor requires surgical excision, whereas fibroadenoma requires no further workup. Both have many overlapping histological features making it difficult to distinguish between a benign fibroadenoma versus the more aggressive phyllodes tumor. This case details a breast mass that was initially believed to be a fibroadenoma, but interval growth at one year follow up resulted in surgical excision with final pathology revealing phyllodes tumor.

Morphologic and genetic heterogeneity in breast fibroepithelial lesions-a comprehensive mapping study

Breast fibroepithelial lesions (FELs) encompass the common fibroadenoma (FA) and relatively rare phyllodes tumour (PT); the latter entity is usually classified as benign, borderline or malignant. Intratumoural heterogeneity is frequently present in these tumours, making accurate histologic evaluation challenging. Despite their rarity, PTs are an important clinical problem due to their propensity for recurrence and, in the case of malignant PT, metastasis. Surgical excision is the mainstay of management. Recent work has uncovered myriad genetic alterations in breast FELs. In this study, exome sequencing was performed on seven cases of morphologically heterogeneous breast FELs, including FAs, PTs of all grades, and a case of metaplastic spindle cell carcinoma arising in PT, in order to elucidate their intratumoural genetic repertoire. Gene mutations identified encompassed cell signalling, tumour suppressor, DNA repair and cell cycle regulating pathways. Mutations common to multiple tumour regions generally showed higher variant allele frequency. Frequent mutations included MED12, TP53, RARA and PIK3CA. Histological observations of increased cellular density and pleomorphism correlated with mutational burden. Phylogenetic analyses revealed disparate pathways of possible tumour progression. In summary, histological heterogeneity correlated with genetic changes in breast FELs.

Accuracy of p53 and ki-67 in the graduation of phyllodes tumor, a model for practical application

Background

The accurate graduation of a phyllodes tumor (PT) is critical for effective treatment as it allows correct surgical management, and avoids inadequate excision for malignant or borderline PT, or surgical overtreatment in benign PT. PTs of the breast are notoriously difficult to classify, and reliable differentiation of a benign PT from a borderline or malignant PT can be problematic, especially among relatively inexperienced pathologists. Although several authors acknowledge a strong relationship between the immunohistochemical expression of p53 and Ki-67 and the histopathological grade of PT—with potential impact on diagnostic accuracy—the literature lacks consensus about which cutoff defines a positive index test. The objective of this study is to establish a practical application score that increases the graduation accuracy of PT through the appropriate use of these auxiliary methods.

Methods

A retrospective study cohort of 146 pathology reviewed PTs surgically removed between January 2000 and December 2015. The Ki-67 test was considered positive if > 10% of neoplastic cells showed nuclear staining. The p53 test was considered positive if > 10% of neoplastic nuclear cells showed nuclear staining in a moderate or strong intensity.

Results

Of the 146 PT cases reviewed, 110 were classified as benign, 16 as borderline, and 20 as malignant. The correlation between age and size with benign, borderline, and malignant subgroups was statistically significant (p < 0.001). Significance was observed in the expression of both Ki-67 and p53 in the comparison of benign, borderline, and malignant PT with p < 0.001 and a 95% confidence interval (CI). When correlating the presence of positivity in either of the two index tests with the diagnosis of borderline or malignant PT, we reached a sensitivity of 100% and a specificity of 91.8 (p < 0.001; 95% CI).

Conclusion

We propose a practical methodology to achieve an accurate grade of PT, based on clearly defined and easy to apply cutoffs of a simple immunohistochemical panel of Ki-67 and p53. A PT positive for either of the index tests should be graded as borderline or malignant, so pathologists can use this test to improve accuracy. We hope this new approach might provide the basis for the development of standardization in using p53 and Ki-67 for grading PT.

Can Radiologist and Pathologist Reach The Truth Together in The Diagnosis of Benign Fibroepithelial Lesions?

Objective

Benign fibroepithelial lesions (BFL) lesions of the breast are various and predominantly benign, although a few can be locally aggressive. Definitive diagnosis of some BFL can be challenging from core needle biopsy (CNB). Radiological findings can help guide the management of the lesions. The aim of this study was to investigate the accuracy rate of CNB results and evaluate the radiological findings of the most common BFL according to the final excision pathology results. The secondary aim was to assess the contribution of the imaging findings to CNB results.

Materials and Methods

A retrospective review was made of 266 patients diagnosed with suspicious BFL, conventional fibroadenoma, complex fibroadenoma, cellular fibroadenoma and benign phyllodes tumor (PT). The study included 132 patients who underwent surgical excision. The radiological and histopathological findings were evaluated.

Results

While 66 patients were diagnosed with more descriptive results on CNB, the other 66 patients were diagnosed with suspicious BFL. Agreement between CNB and excisional pathology was good, when CNB provided a definite diagnosis. While conventional and complex fibroadenoma were observed to have hypo or normal vascularity, cellular fibroadenoma and PT showed hypervascularity. Oval shaped and homogeneous internal echo pattern were significantly associated with conventional fibroadenoma. A heterogeneous internal echo pattern was seen in complex fibroadenomas and PT.

Conclusion

CNB often reaches the correct diagnosis alone when it gives a definite diagnosis. The radiological findings which help in the differentiation of BFL are hypervascularity, oval shape and internal heterogeneity. More accurate results can be obtained when histopathological and radiological findings are evaluated together.

Case Report: presentation of pleomorphic liposarcoma arising in a borderline phyllodes tumor

INTRODUCTION

The stromal component of Phyllodes tumors represents the neoplastic portion of the lesion. A variety of associated malignancies can arise from PTs, with its dual population of cells.

PRESENTATION OF CASE

We share a very rare case of "borderline"breast phillodes tumour with a 75% liposarcoma component. A 48-year-old woman presented at the surgical clinic with a mass in the left breast. On mammograms, the lesion was dense with radiolucent areas inside which were thought to be compatible with fat. The mass was assumed to be breast imaging-reporting and data system (BIRADS) 3 on sonography as it was well contoured. The needle biopsy was reported to be consistent with a fibroadenomatous lesion. The lesion was completely excised. On microscopic examination, the lesion has benign mammary duct epithelium lining the slit-like spaces. The stroma composed of fibrous and adipous tissue. The fibrous part was cellular, and several cells appeared bizarre. Adipous tissue replaced most of the stroma and was diagnosed as pleomorphic liposarcoma.

DISCUSSION

According to the 3 tiered grading criteria of PTs, our case normally suits in borderline category, without liposarcoma component. Heterologous sarcomatous elements usually accompany high grade PTs. Rare cases of benign and borderline PTs with sarcoma component have been reported.

CONCLUSION

The presence of a malignant heterologous component places the tumour into the malignant category regardless of other histological features.