Surgical Management of Benign and Borderline Phyllodes Tumors of the Breast

Imaging and Management of Fibroepithelial Lesions of the Breast: Radiologic-Pathologic Correlation

Fibroepithelial lesions (FELs) are among the most common breast masses encountered by breast radiologists and pathologists. They encompass a spectrum of benign and malignant lesions, including fibroadenomas (FAs) and phyllodes tumors (PTs). FAs are typically seen in young premenopausal women, with a peak incidence at 20-30 years of age, and have imaging features of oval circumscribed hypoechoic masses. Although some FA variants are especially sensitive to hormonal influences and can exhibit rapid growth (eg, juvenile FA and lactational adenomas), most simple FAs are slow growing and involute after menopause. PTs can be benign, borderline, or malignant and are more common in older women aged 40-50 years. PTs usually manifest as enlarging palpable masses and are associated with a larger size and sometimes with an irregular shape at imaging compared with FAs. Although FA and FA variants are typically managed conservatively unless large and symptomatic, PTs are surgically excised because of the risk of undersampling at percutaneous biopsy and the malignant potential of borderline and malignant PTs. As a result of the overlap in imaging and histologic appearances, FELs can present a diagnostic challenge for the radiologist and pathologist. Radiologists can facilitate accurate diagnosis by supplying adequate tissue sampling and including critical information for the pathologist at the time of biopsy. Understanding the spectrum of FELs can facilitate and guide appropriate radiologic-pathologic correlation and timely diagnosis and management of PTs. Published under a CC BY 4.0 license. Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Refining the classification of breast phyllodes tumours

Phyllodes tumours of the breast are uncommon fibroepithelial neoplasms that pose recurrent classification challenges, in large part due to the multiple histological parameters of stromal hypercellularity and atypia, stromal mitotic count, stromal overgrowth and tumour borders, that are used for grading. While the World Health Organization (WHO) Classification of Breast Tumours provides recommendations on diagnostic features, defining criteria are not always applied in routine practice. Lack of concordance among pathologists in typing and grading further underscores the classification difficulties, especially in the borderline category. Although there has been significant molecular information on phyllodes tumours in recent years which has been diagnostically helpful, it has not been translated into daily clinical practice. In order to refine the classification of phyllodes tumours into one that is simple yet comprehensive, reproducible and prognostically precise, a multipronged approach is needed that leverages on global contributions of the International Fibroepithelial Consortium, support by the International Collaboration on Cancer Classification and Research (IC³ R) in amalgamating evidence translation, and guidance from the International Collaboration on Cancer Reporting (ICCR) for standardised reporting. It is hoped that the evidence generated can be used towards refining the classification of phyllodes tumours for the future.

Pretreatment Multiparametric MRI-Based Radiomics Analysis for the Diagnosis of Breast Phyllodes Tumors

BACKGROUND

Preoperative pathological grading assessment is important for patients with breast phyllodes tumors (PTs).

PURPOSE

To develop and validate a clinical-radiomics model based on multiparametric MRI and clinical information for the pretreatment differential diagnosis of PTs.

STUDY TYPE

Retrospective.

POPULATION

A total of 216 patients with PTs, 133 in the training cohort (55 benign PTs [BPTs] and 78 borderline/malignant PTs [BMPTs]) and 83 in the validation cohort (28 BPTs and 55 BMPTs).

FIELD STRENGTH/SEQUENCE

1.5 T and 3 T; T2-weighted imaging (T2WI), precontrast T1-weighted imaging (T1WI) and dynamic contrast-enhanced T1-weighted imaging (DCE-T1WI).

ASSESSMENT

A total of 3138 radiomics features were computed to decode the imaging phenotypes of PTs. To build the classification models, the following workflow was followed: minimum-maximum scaling normalization method, recursive feature elimination based on ridge regression (Ridge-RFE), synthetic minority oversampling technique, and support vector machine classifier. We established several models based on the statistically significant features (Ridge-RFE selected) of each sequence to distinguish BPTs from BMPTs, including precontrast T1WI model, DCE-T1WI phase 1 model, T1WI feature fusion model, T2WI model, T1WI + T2WI model, clinical feature model, conventional MRI characteristics model, and combined clinical-radiomics model.

STATISTICAL TESTS

Univariate analysis was utilized to compare variables between the BPT and BMPT groups. The receiver operating characteristic curve (ROC) analysis was used to evaluate the diagnostic performance of these models.

RESULTS

In the training cohort, the clinical-radiomics model had excellent diagnostic efficiency, with an area under ROC (AUC) of 0.91 ± 0.02 (95% CI: 0.87-0.94). In the validation cohort, the AUCs were 0.79 ± 0.05 (95% CI: 0.70-0.87) for the combined model and 0.77 ± 0.05 (95% CI: 0.67-0.85) for the radiomics model.

DATA CONCLUSION

Compared with conventional MRI characteristics, radiomics features extracted from multiparametric MRI are helpful for improving the accuracy of differentiating the pathological grades of PTs preoperatively. The model based on radiomics and clinical information is expected to become a potential noninvasive tool for the assessment of PTs grades.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 2.

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.

Surgical management in phyllodes tumors of the breast: a systematic review and meta-analysis

BACKGROUND

Information is still controversial in the studies regarding the current optimal surgical management of phyllodes tumors (PTs) of the breast. Local recurrence (LR) may occur with an upgraded in the pathological grade, influencing the prognosis of patients with PT. This systematic review and meta-analysis aimed to investigate the association of LR risk with margin status and margin width which could have significant implications on the surgical management of PT.

METHODS

Independent and comprehensive searches were performed by two authors through five databases including PubMed, Medline, Embase, ScienceDirect and Cochrane Library from January 1990 to October 2021. Studies investigating the association between margin width, margin status and LR rates were considered for inclusion. Study quality was evaluated using the Newcastle-Ottawa Scale (NOS). Meta-analysis was performed using RevMan5.3 software, and statistical heterogeneity was assessed using the Chi-square test and quantified using the I2 statistic. Visual inspection of funnel plots was used to judge publication bias.

RESULTS

A total of 34 articles were included in this article, all of which with NOS scores above 5. Regardless of the PT grade, positive margin significantly increased the risk of LR [odds ratio (OR) 3.64, 95% confidence interval (CI): 2.60-5.12]. No significant difference was found in the risk of LR between the margins <1 and ≥1 cm (OR 1.39, 95% CI: 0.67-2.92). For benign and borderline PTs, there were no significant differences of the LR risk between breast-conserving surgery (BCS) and mastectomy (benign OR 0.68, 95% CI: 0.12-3.78; borderline OR 1.14, 95% CI: 0.29-4.51). While the LR risk was significantly increased by BCS for malignant PT (OR 2.77, 95% CI: 1.33-5.74).

DISCUSSION

Different surgical management strategies should be considered for different PT grades. BCS was a feasible option and margins <1 cm was not significantly associated with LR risk for all grade of PT. After BCS, benign PT with positive margin could adopt the "wait and watch" strategy with regular follow-up, while borderline and malignant PTs were expected to underwent re-excision to ensure negative margins. More studies are still needed to clarify and update the existing conclusions and improve the prognosis of PT patients.

Diagnosis and management of phyllodes tumours for the surgeon: An algorithm

A Phyllodes Tumour (PT) is an uncommon fibroepithelial lesion, with three histological grades - benign, borderline and malignant. PTs cause significant challenges in diagnosis, management and prognostication. Recent publications have clarified the definitions and prognostication of PTs. Contemporary data currently challenge international guidelines on PT management. We performed an in-depth literature review to develop a best-practice management algorithm for PTs. Diagnostic recommendations are that neither current imaging techniques, nor fine-needle biopsies, can reliably diagnose a PT. Core needle biopsy is the optimal diagnostic technique. Indeterminate or suspicious lesions are recommended to undergo an excisional biopsy due to the inherently heterogeneous nature of PTs. Management guidelines are that benign PTs should be completely excised, although an involved margin is acceptable in select situations. Borderline PTs should have a clear margin on excision due to their higher risk of recurrence, as well as the potential for a recurrence to progress to a malignant PT. In malignant PTs, a margin of 3 mm is acceptable as there is no reduction in recurrence risk if margins are >3 mm. Routine axillary surgery is not indicated in PTs, with axillary surgery only indicated in a histologically-confirmed positive axilla. Adjuvant treatment recommendations are that borderline and malignant PTs should be discussed at MDT, with radiotherapy considered in both. Chemotherapy should be discussed in malignant PT patients. In summary, we have developed an up-to-date simple algorithm to guide the surgeon's management of patients diagnosed with PTs and reduce excessive surgery.

Nipple sparing mastectomy for a giant phyllodes tumor; a case report

Introduction

Oncoplastic surgery has come into the limelight in the surgical treatment of breast cancer. In this report, we will introduce our challenge to apply oncoplastic surgery to a benign neoplasm like phyllodes tumor (PT).

Presentation of case

A 45-year-old female visited our hospital complaining of a rapidly growing lump on her left breast. She already had experienced lumpectomy twice on the same breast. Her left breast was occupied by a 14 × 10 cm mass with another small 1.7 × 1.6 cm nodule considered as a daughter lesion. Core needle biopsy suggested that it was a benign PT. We conducted nipple sparing mastectomy (NSM) and immediate reconstruction of the breast by latissimus dorsi muscle flap. During 7-years follow up, she has no recurrence and is satisfied with the reconstructed breast.

Discussion

There are some reports that performed conventional or radical mastectomy with immediate breast or chest wall reconstruction for giant PT. Reports about NSM with breast reconstruction for PT are rare, there are 5 including ours. All the cases accomplished long term recurrent free survival. All except ours were reconstructed by implants. Implant reconstruction is technically easier, but recently, malignant lymphoma after putting breast implant is concerned. Another merit of autologous tissue reconstruction is that they change naturally as age like contralateral breast so that it can achieve better long-term cosmetic result.

Conclusion

NSM with autologous tissue reconstruction is a good option for PT treatment even though it is not malignant.

•

Oncoplastic surgery is a featured field in breast cancer surgery.

•

We can apply oncoplastic surgery to phyllodes tumor.

•

NSM with breast reconstruction can achieve both curability and cosmetic satisfaction.

•

Oncoplastic surgery is important for benign tumor because patients have long life expectancy.

Fibroepithelial tumours of the breast-a review

Fibroepithelial tumours of the breast are biphasic neoplasms composed of both epithelial and stromal elements, including the common fibroadenoma and the infrequent phyllodes tumour. The admixture of epithelium and stroma in the fibroadenoma shows intra- and pericanalicular patterns, and may display a variety of histological changes. Fibroadenoma variants include the cellular, juvenile, myxoid and complex forms. The cellular fibroadenoma may be difficult to distinguish from the benign phyllodes tumour. Stromal mitotic activity can be increased in fibroadenomas in the young and pregnant patients. Phyllodes tumours, neoplasms with the potential for recurrence, show an exaggerated intracanalicular growth pattern with broad stromal fronded architecture and stromal hypercellularity. They are graded into benign, borderline and malignant forms based on histological assessment of stromal features of hypercellularity, atypia, mitotic activity, overgrowth and the nature of the tumour borders. Classification of phyllodes tumours is imperfect, compounded by tumour heterogeneity with overlapping microscopic features among the different grades, especially in the borderline category. Malignant phyllodes tumours can metastasise and cause death. Determining which phyllodes tumours may behave aggressively has been difficult. The discovery of MED12 mutations in the pathogenesis of fibroepithelial tumours, together with other gene abnormalities in the progression pathway, has allowed refinements in diagnosis and prognosis.

Assessment of quantitative dynamic contrast-enhanced MRI in distinguishing different histologic grades of breast phyllode tumor

OBJECTIVES

To investigate whether quantitative DCE-MRI (qDCE-MRI) could help distinguish breast phyllodes tumor (PT) grades.

MATERIALS AND METHODS

This retrospective study included 67 breast PTs (26 benign lesions, 25 borderline lesions, and 16 malignant lesions) from April 2016 to July 2020. MRI was performed with a 1.5-T MR system. Perfusion parameters (K^trans, k_ep, v_e, iAUC60) derived from qDCE-MRI, tumor size, and the mean ADC value were correlated with histologic grades using Spearman's rank correlation coefficient. K^trans, k_ep, v_e, and iAUC60 of three histologic grades were also calculated and compared.

RESULTS

The Spearman correlation coefficient with histologic grade of the tumor size was 0.578 (p < 0.001); the ADC value was not correlated with histologic grades of breast PT (p = 0.059). The K^trans, k_ep, v_e, and iAUC60 of benign breast PTs were significantly lower than those of borderline breast PTs (p < 0.001) and lower than those of malignant breast PTs (p < 0.001). In comparison, the K^trans, v_e, and iAUC60 of borderline breast PTs were significantly lower than those of malignant breast PTs (p < 0.001, p < 0.001, p = 0.007, respectively). For ROC analysis, AUCs of K^trans, v_e, and iAUC60 were higher than tumor size and ADC value for differentiating three PT grades.

CONCLUSION

Quantitative and semi-quantitative perfusion parameters (K^trans, v_e, and iAUC60, especially K^trans) derived from qDCE-MRI showed better diagnosis efficiency than tumor size and ADC for grading breast PTs. Therefore, qDCE-MRI may be helpful for preoperative differentiating breast PT grades.

KEY POINTS

• Quantitative dynamic contrast-enhanced MRI can be used as a complementary noninvasive method to improve the differential diagnosis of breast PT. • K^trans, v_e, and iAUC60 derived from qDCE-MRI showed better diagnosis efficiency than tumor size and ADC for grading breast PTs.

Predicting the pathological grade of breast phyllodes tumors: a nomogram based on clinical and magnetic resonance imaging features

OBJECTIVE

To explore the potential factors related to the pathological grade of breast phyllodes tumors (PTs) and to establish a nomogram to improve their differentiation ability.

METHODS

Patients with PTs diagnosed by post-operative pathology who underwent pretreatment magnetic resonance imaging (MRI) from January 2015 to June 2020 were retrospectively reviewed. Traditional clinical features and MRI features evaluated according to the fifth BI-RADS were analyzed by statistical methods and introduced to a stepwise multivariate logistic regression analysis to develop a prediction model. Then, a nomogram was developed to graphically predict the probability of non-benign (borderline/malignant) PTs.

RESULTS

Finally, 61 benign, 73 borderline and 48 malignant PTs were identified in 182 patients. Family history of tumor, diameter, lobulation, cystic component, signal on fat saturated T₂ weighted imaging (FS T₂WI), BI-RADS category and time-signal intensity curve (TIC) patterns were found to be significantly different between benign and non-benign PTs. The nomogram was finally developed based on five risk factors: family history of tumor, lobulation, cystic component, signal on FS T₂WI and internal enhancement. The AUC of the nomogram was 0.795 (95% CI: 0.639, 0.835).

CONCLUSION

Family history of tumor, lobulation, cystic components, signals on FS T₂WI and internal enhancement are independent predictors of non-benign PTs. The prediction nomogram developed based on these features can be used as a supplemental tool to pre-operatively differentiate PTs grades.

ADVANCES IN KNOWLEDGE

More sample size and characteristics were used to explore the factors related to the pathological grade of PTs and establish a predictive nomogram for the first time.

Benign and borderline phyllodes tumors of the breast: Clinicopathologic analysis of 205 cases with emphasis on the surgical margin status and local recurrence rate

BACKGROUND

The management of benign and borderline phyllodes tumors of the breast with a positive surgical margin is still controversial. Our aim in this study was to evaluate the impact of surgical margin status on the local recurrence rate of benign and borderline phyllodes tumors.

METHODS

We reviewed 205 phyllodes tumors (191 benign, 14 borderline) that were surgically excised at our hospital between 2005 and 2019. Follow-up information extending to at least 6 months after surgery was retrieved from the clinical, radiology, and pathology records.

RESULTS

The initial surgical margin was negative in 54 (26%) cases, close (≤ 1 mm) in 29 (14%) cases, and positive in 122 (60%) cases. Approximately half of the cases with a close margin and two-third of the cases with a positive margin underwent re-excision to obtain negative margins. Three (2.3%) local recurrences were observed among 131 cases with follow-up information, all three with benign phyllodes tumor. Of these three patients, one had a positive final margin, and two had negative final margins. There was no significant difference in the rate of local recurrence between PT with a positive surgical margin versus a close and negative margin.

CONCLUSION

The study results suggest that close clinical and radiologic follow-up may provide a better course of management rather than re-excision when managing positive margins in benign and borderline phyllodes tumors.

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.

Recurrence prediction for breast phyllodes tumours: validation of the Singapore nomogram in Korean women

AIM

The Singapore nomogram was developed to predict recurrence risk of phyllodes tumours (PTs) of the breast based on histological features of stromal atypia, stromal mitoses, stromal overgrowth and surgical margin status. We aimed to validate the utility of the Singapore nomogram in a Korean PT cohort.

METHODS

One hundred and twenty-four patients with Korean PT who underwent surgical resection between 1996 and 2015 were included in this study. Pathology reports and slides were reviewed to obtain histopathologic features and acquire Singapore nomogram scores. The probability of concordance between predicted and observed survivals by means of the Singapore nomogram was evaluated using a concordance index (C-index).

RESULTS

Of the 124 cases, 57 (46%) were diagnosed as benign, 50 (40.3%) as borderline and 17 (13.7%) as malignant. Recurrences occurred in 25 (20.2%) patients. Univariate analysis showed PTs with higher stromal mitotic counts, marked stromal cellularity, stromal overgrowth, positive surgical margin, marked stromal atypia or a malignant grade presented higher risks of recurrence. Multivariate analysis showed stromal mitoses and surgical margin status independently predicted recurrence-free survival. Patients with high nomogram scores were at greater risk of recurrence (HR=1.05, 95% CI: 1.02 to 1.07, p<0.001) with a C-index of 0.762.

CONCLUSION

The Singapore nomogram provided a useful means of predicting PT outcomes in a Korean PT cohort.

Width of margins in phyllodes tumors of the breast: the controversy drags on?-a systematic review and meta-analysis

PURPOSE

Phyllodes tumors (PT) of the breast are rare fibroepithelial neoplasms. Information is controversial in the literature regarding to the optimal surgical management. Most studies suggested margins of at least 10 mm while some recent studies suggested narrower margins without an increased risk of local recurrences (LR) and distant metastases (DM). The objective of this systematic review was to identify and compare studies that assessed these different practices.

METHODS

A systematic review was performed through five databases up to April 2019. Studies exploring the association between the width of margins, subtypes of PT, and the LR and DM rates were considered for inclusion. A statistical model for analyzing sparse data and rare events was used.

RESULTS

Thirteen studies met eligibility criteria and were selected. Considering a threshold of 10 mm (margins < 10 vs margins ≥ 10 mm), the 5-year incidence rate of LR was estimated to be 5.22 vs. 3.63 (diff. -1.59) per 100 person-years for benign PT, 9.60 vs. 7.33 (diff. -2.27) for borderline PT, and 28.58 vs. 21.84 (diff. -6.74) for malignant PT. For DM, it was estimated to be 0.88 vs. 0.86 (diff. -0.02) for benign PT, 1.61 vs. 1.74 (diff. 0.13) for borderline PT, and 4.80 vs 5.18 (diff. 0.38) for malignant PT. The data for a threshold of 1 mm were not sufficient to draw any conclusions.

CONCLUSION

Irrespective of tumor grade, we found that DM was a rarer event than LR. Malignant PT had the highest incidence rate of LR and DM. This meta-analysis found a clear association between width of margins and LR rates. Whatever the tumor grade, surgical margins ≥ 10 mm guaranteed a lower risk of LR than margins < 10 mm. On the other hand, the width of margin did not influence the apparition of DM.

Benign Phyllodes Tumor in Children: A Study of 8 Cases and Review of the Literature

Phyllodes tumor (PT) occurs predominantly in middle-aged women, and although its occurrence in young women, adolescents, and even children is documented, presentation in the pediatric population has been the least well studied because of its rarity. Incompletely defined in children with PT are recurrence rates and optimal surgical management. We retrospectively studied the pathology database of Hartford Hospital from 2010 to 2017 to find all cases of PT in patients 18 years of age or younger. A series of 8 children/adolescents with breast masses diagnosed as benign PT were identified. Patients were 14 to 16 years of age (mean 15.2 y) and tumor size ranged from 2.2 to 7.2 cm (mean 4.4 cm). Both breasts were equally affected. All patients were treated with excision, tantamount to simple enucleation in most cases, and positive or "tumor-abutting" margins were universal. Mean follow-up after surgery was 27.5 months, during which time a single recurrence (at 9 mo) became manifest, which was re-excised and again showed benign PT. There were no pathologic features (including marginal status) that could have predicted the sole recurrence. Despite positive margins, the local recurrence rate for pediatric benign PT appears acceptably low (1 in 8 cases) such that reflex re-excision is probably unnecessary.

Phyllodes tumors of the breast: a retrospective analysis of 57 cases

INTRODUCTION

Current guidelines for the treatment of phyllodes tumors recommend wide local excision for all histopathological subtypes. However, it is unknown which subtypes have tendency to recur after marginal or incomplete excision. This may lead to over-treatment by re-excision surgery for tumors with little or no potential to recur.

MATERIALS AND METHODS

All patients with benign, borderline or malignant phyllode tumors presenting at our institution between 2000 and 2016 were retrospectively analyzed.

RESULTS

A total of 57 patients could be included, of which 39 tumors were benign (60%), three were borderline (5%), and seven were malignant phyllodes tumors (12%). There were also eight phyllodes-like fibroadenomas (14%). Fifty-two patients (91%) underwent local excision as primary treatment, resulting in tumor-positive or close-resection margins in 32 patients (61.5%) of whom five patients (15.6%) had re-excision surgery. During a median follow-up of 5 years, local recurrence occurred in four patients (7.0%) with a median time-to-recurrence of 12 months. Borderline and malignant subtypes were associated with a significantly higher recurrence rate compared to other subtypes (p = 0.039).

CONCLUSION

Although an adequate tumor-negative resection margin should be obtained for borderline and malignant phyllodes tumors, this study confirms that wide local excision is the appropriate primary treatment for all histopathological subtypes. However, if tumor-negative margins were not obtained at first excision, a wait-and-see approach is justified for benign phyllodes tumors.

Re-excision or "wait and watch"-a prediction model in breast phyllodes tumors after surgery

Background

The prognosis of breast phyllodes tumors (PTs) largely depending on the pathological grading, which lacks objectivity. This study aimed to develop a nomogram based on clinicopathological features to evaluate the recurrence probability of PTs following surgery.

Methods

Data from 334 patients with breast PTs, who underwent surgical treatment at Sun Yat-sen Memorial Hospital from January 2005 to December 2014, were used to develop a prediction model. Additionally, data of 36 patients from Peking University Shenzhen Hospital (cohort 1) and data of 140 patients from Sun Yat-sen University Cancer Center (cohort 2) during the same period were used to validate the model. The medical records and tumor slides were retrospectively reviewed. The log-rank and Cox regression tests were used to develop a clinical prediction model of breast PTs. All statistical analyses were performed using R and STATA.

Results

Of all 334 patients included in the primary cohort, 224 had benign, 91 had borderline, and 19 had malignant tumors. The 1-, 3-, and 5-year recurrence-free survival was 98.5%, 97.9%, and 96.8%, respectively. Ultrasound-guided vacuum-assisted biopsy (UGVAB) is a non-inferior treatment application in benign PTs compared with open surgery [hazard ratio (HR), 2.38; 95% confidence interval (CI), 0.59–9.58]. Width of surgical margin, mitoses, and tumor border were identified as independent risk factors for breast PTs. A nomogram was developed based on these three variables. The C-index of internal and external validation was 0.71, 0.67 (cohort 1) and 0.73 (cohort 2), respectively.

Conclusions

The study model presented more concise and objective variables to evaluate the recurrence-free survival of patients after surgery, which can help deciding whether to do a re-excision or “wait and watch”.

Phyllodes Tumors-The Predictors and Detection of Recurrence

BACKGROUND

Phyllodes tumors are rare breast neoplasms and the histopathological grade and surgical margins help guide treatment and follow-up. The traditional surgical teaching is resection with ≥10 mm margins, but are narrower surgical margins acceptable? The purpose of our study was to identify predictors of local recurrence.

METHODS

A retrospective analysis was performed to identify patients with phyllodes tumors who underwent surgery between 2002 and 2014 using a regional pathology database. Electronic medical records were used to identify surgical management, pathological characteristics, and follow-up encounters.

RESULTS

A total of 150 phyllodes tumors were included: 110 of 150 (73%) benign, 21 of 150 (14%) borderline, and 19 of 150 (13%) malignant. At initial surgery, 29 specimens had a positive margin and 15 (56%) underwent re-excision. Seventy tumors had a surgical margin of ≤1 mm, 40 had a margin of 2 to 9 mm, and 11 had a margin of ≥10 mm. There were 11 of 150 (7.3%) locally recurrent tumors: 5 of 11 (45%) benign, 3 of 11 (27%) borderline, and 3 of 11 (27%) malignant. In total, 10 of 11 locally recurrent tumors had a positive margin or ≤1 mm margin at initial surgery.

CONCLUSIONS

Phyllodes tumors can have a personalized treatment approach based on histopathological grade and surgical margins. Borderline and malignant phyllodes tumors with a positive or ≤1 mm surgical margin have an increased risk of recurrence. In benign phyllodes tumors, an optimal narrow negative margin may exist but the traditional ≥10 mm excisional margin is not necessary. Local recurrence rates may be sufficiently low in benign phyllodes tumors that imaging can be performed on the presence of clinical symptoms.

Phyllodes tumor with a benign heterologous osseous component: a diagnostic challenge

Phyllodes tumors (PTs) are rare fibroepithelial neoplasms of the breast and constitute 0.3-1% of all primary breast tumors. They should be characterized in to a benign, borderline or malignant category based on a combination of histological features. PTs can show heterologous components, typically sarcomatous, including osteosarcomatous and chondrosarcomatous. Benign heterologous components are exceedingly rare with only one prior reported case in the English literature. This case emphasizes how difficult establishing a correct diagnosis in PTs with heterologous components can be, especially when the tumor consists mainly of a benign heterologous component. We report the case of a 65 year old woman with a recurrent breast tumor initially misdiagnosed as benign osseous metaplasia. The tumor re-occurred as a malignant PT dominated by benign osseous and chondroid metaplasia. Multiple metastases consisting of primarily mature bone and cartilage were seen in the lungs. On microscopic revision and considering the clinical course the primary breast tumor was re-classified as a borderline PT.

Expression of biomarkers in the AKT pathway correlates with malignancy and recurrence in phyllodes tumours of the breast

AIMS

Phyllodes tumours (PTs) of the breast are uncommon fibroepithelial neoplasms with the potential to recur and metastasise. Apart from histological grading, the expression of biological markers and its relationship with tumour behaviour have been topics of interest. The phosphatidylinositol 3-kinase (PI3K)-AKT pathway regulates diverse biological functions, and is one of the most frequently deregulated pathways in cancers. Little is known of PI3K-AKT pathway alteration in PT. We aim to investigate the alterations in different component of AKT pathway in PTs.

METHODS AND RESULTS

This study investigated the expression of four biological markers involved in this pathway (PTEN, INPP4B, PI3KCA and pAKT) in 134 PTs by the use of immunohistochemistry. According to an immunoscore incorporating staining intensity and proportion, low epithelial INPP4B expression (P = 0.045) was associated with recurrence. A trend of association was found for low epithelial PTEN expression with recurrence (P = 0.090). Interestingly, low epithelial INPP4B expression was also associated recurred tumours (P = 0.043). Stromal PI3KCA expression (P = 0.016) and pAKT expression (P = 0.006) were found to be correlated with increased histological grade, but an opposite trend was seen for stromal INPP4B expression (P = 0.018). In addition, epithelial and stromal PTEN expression, PI3KCA expression and pAKT expression showed strong correlations with each other (P ≤ 0.001).

CONCLUSIONS

These findings indicate that alterations in AKT pathway activation may correlate with malignant transformation and recurrence in PT. Low epithelial INPP4B/PTEN expression is associated with shorter recurrence-free survival. These observations suggest that the pathway may play a crucial role in the biological behaviour and progression of PT, and assessing the expression of this pathway may be of value in diagnosis, grading, prognostication, and management.

Coexisting DCIS and phyllodes breast tumors in Young Chinese women: Case series

INTRODUCTION

Breast cystosarcoma phyllodes tumors are rare and can be benign or malignant. All sub-divisions of phyllodes tumor-benign, borderline and malignant, can harbor carcinomas, although the incidence is extremely rare.

METHODS

We present two nonconsecutive cases of coexisting ductal carcinoma in situ (DCIS) and phyllodes breast tumors in young patients.

METHODS & CASE PRESENTATION

Retrospective review of two patient's medical record was performed. CASE 1: 30-year-old female underwent excisional biopsy for 3.48 cm mass found on ultrasound. Pathology revealed malignant phyllodes tumor with positive margin. On re-excision, patient was found to have 1.5 cm area of ductal carcinoma in situ (DCIS) with positive margin. Patient then underwent re-reexicision of DCIS with negative margin. Patient underwent chemotherapy and tamoxifen for three years without evidence of disease. CASE 2: 30-year-old female presented with 1.3 cm lesion found on ultrasound which core needle biopsy revealed a fibroepithelial tumor. Patient subsequently underwent excision biopsy which found 1.5 cm benign phyllodes tumor and 3.5 mm DCIS within the phyllodes tumor with negative margins. Patient declined additional chemotherapy or hormonal therapy and is currently considering mastectomy.

CONCLUSION

Phyllodes tumors are rare and ones with a coexisting carcinoma are even less frequently encountered. The treatment plan can change upon diagnosis of the carcinoma via the pathology. Treatment should be guided by the type and stage of carcinoma detected which may include additional surgical resection and lymph node sampling.

Local Recurrence of Benign, Borderline, and Malignant Phyllodes Tumors of the Breast: A Systematic Review and Meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to investigate local recurrence (LR) rates among the three grades (benign, borderline, and malignant) of phyllodes tumors (PTs). The study also assessed various risk factors for LR.

METHODS

Electronic articles published between 1 January 1995 and 31 May 2018, were searched and critically appraised. The authors independently reviewed the abstracts and extracted data for LR rates and LR risk factors.

RESULTS

The review incorporated 54 studies with 9234 individual cases. The pooled LR rates were 8% for benign, 13% for borderline, and 18% for malignant PTs. The risk of LR was significantly increased by borderline versus benign PTs (odds ratio [OR] 2.00; 95% confidence interval [CI] 1.68-2.38) and malignant versus borderline PTs (OR 1.28; 95% CI 1.05-1.55). The significant risk factors for LR were mitoses, tumor border (infiltrating vs. pushing), stromal cellularity (moderate/severe vs. mild), stromal atypia (severe vs. mild/absent), stromal overgrowth (severe vs. mild/absent), and tumor necrosis (positive vs. negative). Age and tumor size were not associated with LR risk. The subgroup analysis showed that breast-conserving surgery versus mastectomy and positive versus negative surgical margins were significantly associated with an increased LR risk only in malignant PTs.

CONCLUSIONS

The risk of LR was significantly increased from benign to borderline to malignant PTs. Mitoses, tumor border, stromal cellularity, stromal atypia, stromal overgrowth, tumor necrosis, type of surgery, and surgical margin status may be risk factors for LR. Different management strategies could be considered for different PT grades.

Phyllodes tumors of the breast. The treatment results for 340 patients from a single cancer centre

PURPOSE

The primary treatment of choice for patients with phyllodes tumor of the breast (PTB) is surgery. Two major problems regarding the treatment of such patients remain unclear: what is the appropriate surgical margin and what role is played by adjuvant radiotherapy (ART).

METHODS

The study provides a retrospective review of all patients with PTB treated between 1952 and 2013 at a single institute. The histology slides were re-examined based on WHO criteria. The clinical characteristics and therapy outcomes were obtained. The five-year survival with no evidence of disease (NED) was used as the end point.

RESULTS

The study population comprised 340 women with PTB. Fifty-five percent of the patients were diagnosed with the benign, 11.8% with borderline and 33.2% with malignant PTB. All the patients received primary treatment with surgery (mastectomy-27.1%, and BCS- 72.9%). Local recurrence (LR) was found in 28 (9.1%) of these patients. Four patients with borderline and 8 with malignant PTB who were treated with BCS and had tumor-free margins < 1 cm received ART. None of these patients had LR and all survived 5 years NED. Of the 340 patients from our group, 294 (86.4%) survived five-years NED.

CONCLUSION

The prognosis for benign PTB is excellent and can be cured with surgery alone. A sufficient margin would be 0.1 cm (data from the literature) or 0.2-0.4 cm (our study). We recommend application of ART for such patients but the role of ART in patients with borderline and malignant PTB treated with BCS and with surgical margin < 1 cm remains uncertain.

Fibroepithelial lesions; The WHO spectrum

Fibroepithelial lesions of the breast comprise a morphologically and biologically heterogeneous group of biphasic tumors with epithelial and stromal components that demonstrate widely variable clinical behavior. Fibroadenomas are common benign tumors with a number of histologic variants, most of which pose no diagnostic challenge. Cellular and juvenile fibroadenomas can have overlapping features with phyllodes tumors and should be recognized. Phyllodes tumors constitute a spectrum of lesions with varying clinical behavior and are graded as benign, borderline or malignant based on a set of histologic features according to recommendations by the World Health Organization (WHO). Recent developments have significantly expanded our understanding of the pathogenesis of fibroepithelial lesions, highlighting fibroadenomas as true neoplasms and underscoring a commonality with phyllodes tumors in the form of recurrent MED12 exon 2 mutations. In addition, sequencing studies have elucidated pathways associated with phyllodes tumor progression. Accurate diagnosis and grading of phyllodes tumors are important for patient management and prognosis, as grade broadly correlates with increasing local recurrence risk, and essentially only malignant tumors metastasize. However, classification of fibroepithelial lesions in many cases remains challenging on both core biopsy and excision specimens. A commonly encountered problem at the benign end of the spectrum is the distinction of benign phyllodes tumor from cellular fibroadenoma, which is largely due to the subjective nature of histologic features used in diagnosis and histologic overlap between lesions. Grading is further complicated by the requirement to integrate multiple subjective and ill-defined parameters. On the opposite end of the histologic spectrum, malignant phyllodes tumors must be distinguished from more common metaplastic carcinomas and from primary or metastatic sarcomas, which can be especially difficult in core biopsies. Immunohistochemistry can be useful in the differential diagnosis but should be interpreted with attention to caveats. This review provides an overview and update on the spectrum of fibroepithelial lesions, with special emphasis on common problems and practical issues in diagnosis.