Predicting clinical behaviour of breast phyllodes tumours: a nomogram based on histological criteria and surgical margins

Integrated multi-omics profiling reveals a clinically relevant molecular feature and potential therapeutic target on phyllodes tumors of breast

Phyllodes tumors (PTs) has an increased risk of local relapse and distant metastases. Molecular features correlating to histologic grade and aggressive behavior of PTs are poorly characterized. Here, whole exome sequencing (WES) was performed to explore genetic mutations in 61 samples of fibroepithelial breast tumors, including 16 fibroadenomas (FAs), 18 benign PTs, 19 borderline PTs, and 8 malignant PTs. Our work clearly shows that FA, benign PT, borderline PT, and malignant PT are independent entities at the genomic level. They may exist as hidden sub-clones carrying specific genetic alterations. Malignant PT-specific mutations present a multi-gene co-mutational pattern suggesting a synergistic effect of co-mutated genes in processes associated with malignant behavior. Moreover, we made a combined genomic and transcriptomic analysis, which presented a mutated gene-based interaction with expression profiles. We found that EGFR mutations (c.710C > T, c.758A > G, c.1295A > G, and c.2156G > C) serve as a hub of interaction network in borderline PTs, which suggests EGFR tyrosine kinase inhibitors (EGFRi) might be effective for borderline PTs. We found TP53 mutations (c.730G > T, c.844C > T, and c.1019delA) serves as a hub event of molecular changes of malignant PTs. Thus, our study based on the omics platforms of genome and transcriptome provides a better understanding of relapse process and the potential targeted therapy in PTs, which is pivotal in improving molecular-guided patient selection and designing clinically relevant combination strategies.

Vacuum-assisted excision: a safe minimally invasive option for benign phyllodes tumor diagnosis and treatment-a systematic review and meta-analysis

Synopsis

This is a systematic review and meta-analysis comparing surgical excision with percutaneous ultrasound-guided vacuum-assisted excision (US-VAE) for the treatment of benign phyllodes tumor (PT) using local recurrence (LR) as the endpoint.

Objective

To determine the frequency of local recurrence (LR) of benign phyllodes tumor (PT) after ultrasound-guided vacuum-assisted excision (US-VAE) compared to the frequency of LR after surgical excision.

Method

A systematic review and meta-analysis [following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standard] was conducted by comparing LR in women older than 18 years treated for benign PT by US-VAE compared with local surgical excision with at least 12 months of follow-up. Studies were retrieved from PubMed, Scopus, Web of Science, and Embase. The pooled effect measure used was the odds ratio (OR) of recurrence.

Results

Five comparative prospective or retrospective observational studies published between January 1, 1992, and January 10, 2022, comparing surgical excision with percutaneous US-VAE for LR of benign PT met the selection criteria. Four were retrospective observational cohorts, and one was a prospective observational cohort. A total of 778 women were followed up. Of them, 439 (56.4%) underwent local surgical excision, and 339 (43.6%) patients had US-VAE. The median age of patients in the five studies ranged from 33.7 to 39 years; the median size ranged from 1.5 cm to 3.0 cm, and the median follow-up ranged from 12 months to 46.6 months. The needle gauge ranged from 7G to 11G. LR rates were not statically significant between US-VAE and surgical excision (41 of 339 versus 34 of 439; OR 1.3; p = 0.29).

Conclusion

This meta-analysis suggests that using US-VAE for the removal of benign PT does not increase local regional recurrence and is a safe minimally invasive therapeutic option.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022309782.

Detailed DNA methylation characterisation of phyllodes tumours identifies a signature of malignancy and distinguishes phyllodes from metaplastic breast carcinoma

Phyllodes tumours (PTs) are rare fibroepithelial lesions of the breast that are classified as benign, borderline, or malignant. As little is known about the molecular underpinnings of PTs, current diagnosis relies on histological examination. However, accurate classification is often difficult, particularly for distinguishing borderline from malignant PTs. Furthermore, PTs can be misdiagnosed as other tumour types with shared histological features, such as fibroadenoma and metaplastic breast cancers. As DNA methylation is a recognised hallmark of many cancers, we hypothesised that DNA methylation could provide novel biomarkers for diagnosis and tumour stratification in PTs, whilst also allowing insight into the molecular aetiology of this otherwise understudied tumour. We generated whole-genome methylation data using the Illumina EPIC microarray in a novel PT cohort (n = 33) and curated methylation microarray data from published datasets including PTs and other potentially histopathologically similar tumours (total n = 817 samples). Analyses revealed that PTs have a unique methylome compared to normal breast tissue and to potentially histopathologically similar tumours (metaplastic breast cancer, fibroadenoma and sarcomas), with PT-specific methylation changes enriched in gene sets involved in KRAS signalling and epithelial-mesenchymal transition. Next, we identified 53 differentially methylated regions (DMRs) (false discovery rate < 0.05) that specifically delineated malignant from non-malignant PTs. The top DMR in both discovery and validation cohorts was hypermethylation at the HSD17B8 CpG island promoter. Matched PT single-cell expression data showed that HSD17B8 had minimal expression in fibroblast (putative tumour) cells. Finally, we created a methylation classifier to distinguish PTs from metaplastic breast cancer samples, where we revealed a likely misdiagnosis for two TCGA metaplastic breast cancer samples. In conclusion, DNA methylation alterations are associated with PT histopathology and hold the potential to improve our understanding of PT molecular aetiology, diagnostics, and risk stratification. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Integrating single-cell and spatial transcriptomes reveals COL4A1/2 facilitates the spatial organisation of stromal cells differentiation in breast phyllodes tumours

BACKGROUND

Breast phyllodes tumours (PTs) are a unique type of fibroepithelial neoplasms with metastatic potential and recurrence tendency. However, the precise nature of heterogeneity in breast PTs remains poorly understood. This study aimed to elucidate the cell subpopulations composition and spatial structure and investigate diagnostic markers in the pathogenesis of PTs.

METHODS

We applied single-cell RNA sequencing and spatial transcriptomes on tumours and adjacent normal tissues for integration analysis. Immunofluorescence experiments were conducted to verify the tissue distribution of cells. Tumour cells from patients with PTs were cultured to validate the function of genes. To validate the heterogeneity, the epithelial and stromal components of tumour tissues were separated using laser capture microdissection, and microproteomics data were obtained using data-independent acquisition mass spectrometry. The diagnostic value of genes was assessed using immunohistochemistry staining.

RESULTS

Tumour stromal cells harboured seven subpopulations. Among them, a population of widely distributed cancer-associated fibroblast-like stroma cells exhibited strong communications with epithelial progenitors which underwent a mesenchymal transition. We identified two stromal subpopulations sharing epithelial progenitors and mesenchymal markers. They were inferred to further differentiate into transcriptionally active stromal subpopulations continuously expressing COL4A1/2. The binding of COL4A1/2 with ITGA1/B1 facilitated a growth pattern from the stroma towards the surrounding glands. Furthermore, we found consistent transcriptional changes between intratumoural heterogeneity and inter-patient heterogeneity by performing microproteomics studies on 30 samples from 11 PTs. The immunohistochemical assessment of 97 independent cohorts identified that COL4A1/2 and CSRP1 could aid in accurate diagnosis and grading.

CONCLUSIONS

Our study demonstrates that COL4A1/2 shapes the spatial structure of stromal cell differentiation and has important clinical implications for accurate diagnosis of breast PTs.

Malignant phyllodes tumour with lymph node metastasis: a diagnostic conundrum resolved by next generation DNA sequencing

A malignant neoplasm with spindle cell and chondroid differentiation in the breast, metastatic to lymph node. In this context, a metaplastic carcinoma is typically favored given the exceptional nature of lymph node metastases in malignant phyllodes tumors (MPT). However, we demonstrate pathognomonic hotspot mutations in MED12 and the promoter of the TERT gene by targeted next-generation DNA sequencing, supporting a diagnosis of MPT.

Are both distinct epithelial and stromal cells molecular analysis from phyllodes tumors versus fibroadenoma components affected in breast fibroepithelial progression?

PURPOSE

To determine molecular events involved in the tumorigenesis of phyllodes tumors (PT) and the role of each stromal (SC) and epithelial (EC) cell.

METHODS

Frozen breast samples enriched with epithelial and stromal cells from three fibroadenomas and 14 PT were retrieved and laser microdissected. Sanger and polymerase chain reaction-based sequencing of exon 2 MED12 and TERT promoter hotspot mutations were performed; 44K microarray platform was used to analyze gene expression.

RESULTS

All three fibroadenomas (FAs) presented mutations in MED12, but not in TERT, whose mutation was observed in five of the 14 PTs. EC and SC of each affected tumor displayed identical alterations. Of the total differentially expressed genes (DEG) (EC = 1,543 and SC = 850), 984 were EC-eDEGs and 291 were SC-eDEGs. We found a high similarity of diseases and functions enriched by both cell types, but dissimilarity in the number of enriched canonical pathways. Three signaling canonical pathways overlapping with EC and SC were predicted to be activated in one cell type and inactivated in the other, while no overlap in eDEGs was assigned to them. We also identified 13 EC-eDEGs and five SC-eDEGs enriched networks, in which the SC-eDEGs were able to segregate FA from PT samples.

CONCLUSIONS

Identical TERT mutations from both SC and ES origins might affect the PTs tumorigenesis. Gene expression differences suggest coordinated molecular processes between these components with determinant differences acquired by SC, able to fully distinguish PTs from FAs lesions.

Metastatic and Malignant Phyllodes Tumors of the Breast: An Update for Current Management

Metastatic, malignant phyllodes tumor (PT) of the breast is a rare and aggressive neoplasm. Currently, there is no agreed upon consensus as to best management practices. A systematic review of literature was conducted investigating surgical, chemotherapeutic, and radiotherapeutic management for metastatic PT. Databases employed to identify articles included Embase, PubMed, and SAGE Journals. Diagnosis of metastatic PT has been of significant difficulty to radiologists as it is often confused with fibroadenomas. Surgically, metastatectomy has been correlated with increased overall survival (of 25.9 versus 9.9 months; P = .01). Radiotherapy has often been associated with palliation and pain control in metastatic, malignant neoplasia. However, one study showed that in malignant PT, radiation was associated with significantly lower rates of local recurrence (OR: 0.048 versus 0.209). Anthracycline containing chemotherapy regimens has been associated with improved overall survival (22.4 months versus 13.2 months; P = .040). Further research must be conducted into this rare malignancy to elucidate accurate diagnosis and care for patients with advanced metastatic or malignant phyllodes tumors.

Comprehensive Clinical-Pathologic Assessment of Malignant Phyllodes Tumors: Proposing Refined Diagnostic Criteria

The latest World Health Organization classification of breast tumors recommends diagnosing malignant phyllodes tumors (MPTs) when all 5 morphologic features are present: permeative borders, marked stromal cellularity, marked stromal cytologic atypia, ≥10 mitoses per 10 high-power fields (HPF), and stromal overgrowth. We assessed the performance of this recommendation to capture MPTs and features predictive of distant metastasis in a multi-institutional retrospective study. Of 65 MPTs, most cases had at least focally permeative borders (58, 89%), with marked stromal cellularity in 40 (61.5%), marked atypia in 38 (58.5%), ≥10 mitoses per 10 HPF in 50 (77%), and stromal overgrowth in 56 (86%). Distant metastases were observed in 20 (31%) patients (median follow-up 24.5 mo, 1 to 204). Only 13 of 65 (20%) cases had all 5 morphologic features, while only 7 of 20 (35%) cases with distant metastases had all 5 features. In univariate analysis, only marked stromal atypia ( P =0.004) and cellularity ( P =0.017) were associated with decreased distant metastasis-free survival. In multivariate Cox regression, the combination of stromal overgrowth, marked stromal cellularity, and atypia (C-index 0.721, 95% CI: 0.578, 0.863) was associated with decreased distant metastasis-free survival. The current World Health Organization recommendation will miss a significant number of MPTs with distant metastases. We propose refined diagnostic criteria for MPTs: (1) stromal overgrowth combined with ≥1 feature(s) (marked cellularity, marked atypia, or ≥10 mitoses per 10 HPF), or (2) in the absence of stromal overgrowth, marked cellularity combined with ≥1 feature(s) (permeative borders, marked atypia, or ≥10 mitoses per 10 HPF).

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.

Small Bowel Metastases From Malignant Phyllodes Breast Tumor Detected by 18 F-FDG PET/CT

ABSTRACT

The most common sites of distant metastases are lung, bone, pleura, and mediastinum in malignant phyllodes breast tumors. However, small bowel metastasis from malignant phyllodes breast tumors is rare. We reported that using CT and FDG PET/CT imaging we identified a case with small bowel metastasis from breast cancer. PET/CT scan showed that high 18 F-FDG uptake occurred in the duodenum and jejunum. Histopathology and immunohistochemistry analyses further confirmed that malignant phyllodes tumors are derived from the breast.

Versican core protein aids in the diagnosis and grading of breast phyllodes tumor

Phyllodes tumors (PTs) are biphasic fibroepithelial lesions that occur in the breast. Diagnosing and grading PTs remains a challenge in a small proportion of cases, due to the lack of reliable specific biomarkers. We screened a potential marker versican core protein (VCAN) through microproteomics analysis, validated its role for the grading of PTs by immunohistochemistry, and analyzed the correlation between VCAN expression and clinicopathological characteristics. Cytoplasmic immunoreactivity for VCAN was identified in all benign PT samples, among which 40 (93.0 %) showed VCAN-positive staining in ≥50 % of tumor cells. Eight (21.6 %) borderline PT samples showed VCAN-positive staining in ≥50 % of the cells with weak to moderate staining intensity, whereas 29 samples (78.4 %) showed VCAN-positive staining in <50 % of the cells. In malignant PTs, 16 (84.2 %) and three (15.8 %) samples showed VCAN-positive staining in <5 % and 5-25 % of stromal cells, respectively. Fibroadenomas showed a similar expression pattern to benign PTs. Fisher's exact test showed that the percentages of positive cells (P < .001) and staining intensities (P < .001) of tumor cells were significantly different between the five groups. VCAN positivity was associated with tumor categories (P < .0001) and CD34 expression (P < .0001). The expression of VCAN gradually decreases as the tumor categories increases, following recurrence. To the best of our knowledge, our results are the first in the literature to reveal that VCAN is useful for diagnosing and grading PTs. The expression level of VCAN appeared to be negatively associated with PT categories, suggesting that dysregulation of VCAN may be involved in the tumor progression of PTs.

Differentiation Between Phyllodes Tumors and Fibroadenomas of Breast Using Mammography-based Machine Learning Methods: A Preliminary Study

OBJECTIVE

To investigate the diagnostic performance of a mammography-based radiomics model for distinguishing phyllodes tumors (PTs) from fibroadenomas (FAs) of the breast.

MATERIALS AND METHODS

A total of 156 patients were retrospectively included (75 with PTs, 81 with FAs) and divided into training and validation groups at a ratio of 7:3. Radiomics features were extracted from craniocaudal and mediolateral oblique images. The least absolute shrinkage and selection operator (LASSO) algorithm and principal component analysis (PCA) were performed to select features. Three machine learning classifiers, including logistic regression (LR), K-nearest neighbor classifier (KNN) and support vector machine (SVM), were implemented in the radiomics model, imaging model and combined model. Receiver operating characteristic curves, area under the curve (AUC), sensitivity and specificity were computed.

RESULTS

Among 1084 features, the LASSO algorithm selected 17 features, and PCA further selected 6 features. Three machine learning classifiers yielded the same AUC of 0.935 in the validation group for the radiomics model. In the imaging model, KNN yielded the highest accuracy rate of 89.4% and AUC of 0.947 in the validation set. For the combined model, the SVM classifier reached the highest AUC of 0.918 with an accuracy rate of 86.2%, sensitivity of 83.9%, and specificity of 89.4% in the training group. In the validation group, LR yielded the highest AUC of 0.973. The combined model had a relatively higher AUC than the radiomics model or imaging model, especially in the validation group.

CONCLUSIONS

Mammography-based radiomics features demonstrate good diagnostic performance for discriminating PTs from FAs.

High grade phyllodes tumor with osteosarcomatous differentiation: Case report and review of the literature

Phyllodes tumors (PTs) are rare fibroepithelial malignancies of the breast, accounting for less than 1% of malignant breast tumors. PTs are usually solitary tumors but can be associated with other malignancies, such as DCIS or invasive carcinomas and sarcomas. Osteosarcomatous differentiation of a malignant phyllodes tumor is rare, and differentiation of this rare breast tumor from other entities is of vital importance to clinicians due for appropriate treatment and prognosis. We present a case of rare high-grade phyllodes tumor with osteosarcomatous differentiation presenting on mammogram as a calcified lobulated mass; ultrasound revealed a 1.5 cm irregularly calcified mass, suggestive of bone. An ultrasound-guided core biopsy and subsequent lumpectomy revealed a cellular stroma with osteoid stromal matrix and cytologic atypia with bone formation. At 18 months postprocedure, a recurrence was identified at the previous surgical site, and the patient underwent a mastectomy. Here we present a single case of high-grade PT with osteosarcomatous differentiation and a comprehensive literature review, highlighting the mammographic and histologic characteristics of this rare presentation.

Disseminated malignant phyllodes: Presentation after a decade

Phyllodes tumors are rare biphasic fibroepithelial lesions of the breast and account for 0.3%-0.5% of primary breast tumors. Malignant phyllodes tumor has a 10%-26% risk of distant metastasis. The most common site of metastasis is lungs followed by bone and soft tissue. This is a rare case of a 42-year-old female with a previous history of malignant phyllodes tumor breast. She presented after 10 years with metastases to multiple sites including lung, abdominal wall, retroperitoneum, bone, and brain. These tumors have a poor overall survival. Accurate diagnosis and aggressive management of malignant phyllodes tumors can help in effective treatment at diagnosis and for close follow-up of the patients.

The application of clinical variable-based nomogram in predicting overall survival in malignant phyllodes tumors of the breast

Background: We aimed to explore prognostic risk factors in patients with malignant phyllodes tumors (PTs) of the breast and construct a survival prediction model. Methods: The Surveillance, Epidemiology, and End Results database was used to collect information on patients with malignant breast PTs from 2004 to 2015. The patients were randomly divided into training and validation groups using R software. Univariate and multivariate Cox regression analyses were used to screen out independent risk factors. Then, a nomogram model was developed in the training group and validated in the validation group, and the prediction performance and concordance were evaluated. Results: The study included 508 patients with malignant PTs of the breast, including 356 in the training group and 152 in the validation group. Univariate and multivariate Cox proportional hazard regression analyses showed that age, tumor size, tumor stage, regional lymph node metastasis (N), distant metastasis (M) and tumor grade were independent risk factors for the 5-year survival rate of patients with breast PTs in the training group (p < 0.05). These factors were used to construct the nomogram prediction model. The results showed that the C-indices of the training and validation groups were 0.845 (95% confidence interval [CI] 0.802-0.888) and 0.784 (95% CI 0.688-0.880), respectively. The calibration curves of the two groups were close to the ideal 45° reference line and showed good performance and concordance. Receiver operating characteristic and decision curve analysis curves showed that the nomogram has better predictive accuracy than other clinical factors. Conclusion: The nomogram prediction model constructed in this study has good predictive value. It can effectively assess the survival rates of patients with malignant breast PTs, which will aid in the personalized management and treatment of clinical patients.

Differentiation between Phyllodes Tumors and Fibroadenomas through Breast Ultrasound: Deep-Learning Model Outperforms Ultrasound Physicians

The preoperative differentiation of breast phyllodes tumors (PTs) from fibroadenomas (FAs) plays a critical role in identifying an appropriate surgical treatment. Although several imaging modalities are available, reliable differentiation between PT and FA remains a great challenge for radiologists in clinical work. Artificial intelligence (AI)-assisted diagnosis has shown promise in distinguishing PT from FA. However, a very small sample size was adopted in previous studies. In this work, we retrospectively enrolled 656 breast tumors (372 FAs and 284 PTs) with 1945 ultrasound images in total. Two experienced ultrasound physicians independently evaluated the ultrasound images. Meanwhile, three deep-learning models (i.e., ResNet, VGG, and GoogLeNet) were applied to classify FAs and PTs. The robustness of the models was evaluated by fivefold cross validation. The performance of each model was assessed by using the receiver operating characteristic (ROC) curve. The area under the curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were also calculated. Among the three models, the ResNet model yielded the highest AUC value, of 0.91, with an accuracy value of 95.3%, a sensitivity value of 96.2%, and a specificity value of 94.7% in the testing data set. In contrast, the two physicians yielded an average AUC value of 0.69, an accuracy value of 70.7%, a sensitivity value of 54.4%, and a specificity value of 53.2%. Our findings indicate that the diagnostic performance of deep learning is better than that of physicians in the distinction of PTs from FAs. This further suggests that AI is a valuable tool for aiding clinical diagnosis, thereby advancing precision therapy.

Clinico-Pathological Factors Determining Recurrence of Phyllodes Tumors of the Breast: The 25-Year Experience at a Tertiary Cancer Centre

BACKGROUND

Phyllodes tumors (PTs) of the breast are rare fibroepithelial tumors that are generally more prone to recurrence.

AIMS AND OBJECTIVES

This study aimed to assess the clinicopathological features, diagnostic modalities, and therapeutic interventions, along with their respective outcomes, to identify the factors associated with a recurrence of PTs of the breast.

METHODOLOGY

A retrospective cohort and observational study was conducted, which entailed analyzing the clinicopathological data of patients who were previously diagnosed or presented with PTs of the breast between 1996 and 2021. Data included the total number of patients diagnosed with PTs of the breast and their ages, tumor grade on initial biopsy, tumor location (left or right breast), tumor size, therapeutic interventions carried out (including surgery-either mastectomy or lumpectomy-and adjuvant radiotherapy), final tumor grade, recurrence status, type of recurrence, and time to recurrence.

RESULTS

We analyzed data on a total of 87 patients who were pathologically proven to have PTs, and 46 patients (52.87%) were found to have recurrences. All patients were female, with a mean age at diagnosis of 39 years (range 15-70). Patients aged <40 years had the highest incidence of recurrence, with a rate of 54.35% (n = 25/46), followed by patients aged >40 years, with a rate of recurrence of 45.65% (n = 21/46). A total of 55.4% of patients presented with primary PTs and 44.6% had recurrent PTs at presentation. The average time to local recurrence (LR) from the completion of treatment was 13.8 months, whereas for systemic recurrence (SR), it was 15.29 months. Surgery (mastectomy/lumpectomy) was the major determinant for local recurrence (p < 0.05).

CONCLUSION

Patients who received adjuvant radiotherapy (RT) had a minimal recurrence of PTs. Patients who were found to have a malignant biopsy on initial diagnosis (triple assessment) had a higher incidence of PTs and were more prone to SR than LR. Surgery was a determining factor in the increased rate of LR, with lumpectomy associated with a higher incidence of LR than mastectomy.

Gene Expression Profiling of Fibroepithelial Lesions of the Breast

Fibroepithelial lesions of the breast (FELs) are a heterogeneous group of neoplasms exhibiting a histologic spectrum ranging from fibroadenomas (FAs) to malignant phyllodes tumors (PTs). Despite published histologic criteria for their classification, it is common for such lesions to exhibit overlapping features, leading to subjective interpretation and interobserver disagreements in histologic diagnosis. Therefore, there is a need for a more objective diagnostic modality to aid in the accurate classification of these lesions and to guide appropriate clinical management. In this study, the expression of 750 tumor-related genes was measured in a cohort of 34 FELs (5 FAs, 9 cellular FAs, 9 benign PTs, 7 borderline PTs, and 4 malignant PTs). Differentially expressed gene analysis, gene set analysis, pathway analysis, and cell type analysis were performed. Genes involved in matrix remodeling and metastasis (e.g., MMP9, SPP1, COL11A1), angiogenesis (VEGFA, ITGAV, NFIL3, FDFR1, CCND2), hypoxia (ENO1, HK1, CYBB, HK2), metabolic stress (e.g., UBE2C, CDKN2A, FBP1), cell proliferation (e.g., CENPF, CCNB1), and the PI3K-Akt pathway (e.g., ITGB3, NRAS) were highly expressed in malignant PTs and less expressed in borderline PTs, benign PTs, cellular FAs, and FAs. The overall gene expression profiles of benign PTs, cellular FAs, and FAs were very similar. Although a slight difference was observed between borderline and benign PTs, a higher degree of difference was observed between borderline and malignant PTs. Additionally, the macrophage cell abundance scores and CCL5 were significantly higher in malignant PTs compared with all other groups. Our results suggest that the gene-expression-profiling-based approach could lead to further stratification of FELs and may provide clinically useful biological and pathophysiological information to improve the existing histologic diagnostic algorithm.

Organoid models derived from patients with malignant phyllodes tumor of the breast

PURPOSE

Phyllodes tumor of the breast is a kind of rare neoplasm, which accounts for less than 1% of all breast tumors. Malignant phyllodes tumor (MPT) is the highest risk subtype of phyllodes tumor, and is characterized by the tendency of local recurrence and distant metastasis. The prediction of prognosis and the individual therapy for MPT is still challenging. It's urgent to develop a new reliable in vitro preclinical model in order to understand this disease better and to explore appropriate anticancer drugs for individual patients.

METHODS

Two surgically resected MPT specimens were processed for organoid establishment. MPT organoids were subsequently subjected to H&E staining, immunohistochemical analysis and drug screening, respectively.

RESULTS

We successfully established two organoid lines from different patients with MPT. The MPT organoids can well retain the histological features and capture the marker expression in original tumor tissues, including p63, vimentin, Bcl-2, CD34, c-Kit, and Ki-67, even after a long-term culture. The dose titration tests of eight typical chemotherapeutic drugs (paclitaxel, docetaxel, vincristine, doxorubicin, cisplatin, gemcitabine, cyclophosphamide, ifosfamide) on the two MPT organoid lines showed patient-specific drug responses and varying IC₅₀ values. Of all the drugs, doxorubicin and gemcitabine showed the best anti-tumor effect on the two organoid lines.

CONCLUSION

Organoids derived from MPT may be a novel preclinical model for testing personalized therapies for patients with MPT.

Malignant phyllodes tumors of the breast: the malignancy grading and associations with prognosis

PURPOSE

This study aimed to correlate clinicopathological parameters with survival outcomes in a cohort of patients diagnosed with malignant phyllodes tumors (MPTs). We also analyzed the malignancy grade of MPTs and investigated the prognostic significance of the malignancy grading system.

METHODS

Clinicopathological parameters, malignancy grades, and clinical follow-up data of 188 women diagnosed with MPTs in a single-institution were analyzed. MPTs of the breast were grouped according to stromal atypia, stromal overgrowth, mitotic count, tumor differentiation, and necrosis. A Fleiss' kappa statistic was calculated to test the agreement between the pathologists for the grading of MPTs. Disease-free survival (DFS), distant metastasis-free survival (DMFS) and overall survival (OS) were estimated using the Kaplan-Meier method and compared between groups using the log-rank test. Cox regression was carried out to identify factors predictive of locoregional recurrence (LRR), distant metastasis (DM) and death.

RESULTS

A total of 188 MPTs were classified according to the malignancy grading system: 88 (46.8%) as low grade, 77 (41%) as an intermediate grade, and 23 (12.2%) as high grade. Excellent agreement between pathologists for the grading of MPTs (Fleiss' kappa 0.807). In our study population, the occurrence of DM and death were associated with the malignancy grade of MPTs (P < 0.001). Based on the DFS curves, the presence of heterologous elements (P = 0.025) and younger age (P = 0.014) were independent prognostic indicators. Additionally, the malignancy grade retained independent prognostic significance for predicting DMFS and OS (P < 0.001 and P = 0.009).

CONCLUSIONS

Higher malignancy grade, presence of heterologous elements, younger age, larger tumor size, and recent rapid tumor growth are poor prognostic factors for MPTs of the breast. The malignancy grading system may be generalized in the future.

Recurrence is Not Associated with Margin Status in Phyllodes Tumor

BACKGROUND

Phyllodes tumor (PT) is a rare fibroepithelial neoplasm of the breast. The proper extent of resection is still under debate. This study aimed to investigate the optimal surgical margin to prevent recurrence after surgery for PT and to evaluate risk factors for local recurrence (LR).

METHODS

Retrospective analysis of a prospective cohort database was performed. Patients who underwent curative surgery for PT at Seoul National University Bundang Hospital between July 2003 and February 2022 were reviewed.

RESULTS

Of the 439 patients included, 285 were benign, 129 were borderline, and 25 were malignant. There was no statistically significant difference in 5-year disease-free survival (DFS) between margin-negative and margin-involved patients (87.3% vs. 85.1%, p = 0.081). When patients were classified into groups, according to margin status, as conventional (≥ 1 cm from tumor), close (< 1 cm from tumor), or involved, 5-year DFS rates were also similar (100% vs. 86.9% vs. 85.1%, p = 0.170). In subgroup analysis for different histologic grades, 5-year DFS was not affected by margin involvement. In univariate analysis, large tumor size (> 5 cm; hazard ratio [HR] 2.857, p = 0.028) and infiltrative tumor border (HR 3.096, p = 0.012) were independent risk factors for LR. Further multivariate analysis found both factors to be prognostic.

CONCLUSIONS

Recurrence was not significantly influenced by margin status in all histological grades. In benign and borderline tumors, local excision without wide surgical margins could be sufficient, and watchful waiting could be an option for patients with positive margins after initial surgery.

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.

Staging Systems and Nomograms for Soft Tissue Sarcoma

Reliable tools for prognosis prediction are crucially needed by oncologists so they can tailor individual treatments. However, the wide spectrum of histologies and prognostic behaviors of sarcomas challenges their development. In this field, nomograms could definitely better account for their granularity compared to the more widely used AJCC/UICC TNM staging system. Nomograms are predictive tools that incorporate multiple risk factors and return a numerical probability of a clinical event. Since the development of the first nomogram in 2002, several other nomograms have been built, either general, site-specific, histology-specific, or both. Recently, some new “dynamic” nomograms and prognostic tools have been developed, allowing doctors to “recalculate” a patient’s prognosis by taking into account the time since primary surgery, the event history, and the potential time-dependent effect of covariates. Due to these new tools, prognosis prediction is no longer limited to the time of the first computation but can be adapted and recalculated based on the occurrence (or not) of any event as time passes from the first computation. In this review, we aimed to give an overview of the available nomograms for STS and to help clinicians in the process of selecting the best tool for each patient.

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.

Racial-ethnic variations in phyllodes tumors among a multicenter United States cohort

BACKGROUND AND OBJECTIVES

Previous studies have identified racial-ethnic differences in the diagnostic patterns and recurrence outcomes of women with phyllodes tumors (PT). However, these studies are generally limited in size and generalizability. We therefore sought to explore racial-ethnic differences in age, tumor size, subtype, and recurrence in a large US cohort of women with PT.

METHODS

We performed an 11-institution retrospective review of women with PT from 2007 to 2017. Differences in age at diagnosis, tumor size and subtype, and recurrence-free survival according to race-ethnicity.

RESULTS

Women of non-White race or Hispanic ethnicity were younger at the time of diagnosis with phyllodes tumor. Non-Hispanic Other women had a larger proportion of malignant PT. There were no differences in recurrence-free survival in our cohort.

CONCLUSIONS

Differences in age, tumor size, and subtype were small. Therefore, the workup of young women with breast masses and the treatment of women with PT should not differ according to race-ethnicity. These conclusions are supported by our finding that there were no differences in recurrence-free survival.

Margin Status and Local Recurrence in Phyllodes Tumours of the Breast: A Canadian Series

BACKGROUND

Phyllodes tumours of the breast are rare fibroepithelial neoplasms with a propensity for recurrence. While surgical excision remains the standard of care, the optimal margin width is an area of active investigation. Recent studies have questioned the necessity for wide, local excision.

METHODS

We conducted a retrospective, cohort study of patients with phyllodes tumours treated at our institution between 2003 and 2021. Demographic, histopathological, and recurrence data were captured; malignant phyllodes were excluded. Cox proportional hazard models were used to identify covariates associated with local recurrence.

RESULTS

Of 187 patients with phyllodes tumours, 82.9% (n = 155) were classified as benign while 17.1% (n = 32) were borderline. Initial surgical margins were positive in 26.2% (n = 49), < 2 mm in 50.8% (n = 95), and ≥ 2 mm in 23% (n = 43) patients. Among patients with positive margins, 61.2% (n = 30) underwent margin revision. At a median follow-up of 2.9 years, the recurrence rate was 3.7%. On univariate analysis, only a positive margin at the time of initial surgery and not margin width was significantly associated with a higher rate of disease recurrence (hazard ratio [HR] 9.52, 95% confidence interval [CI] 1.85-49.2), as was a size greater than 4 cm on preoperative imaging (HR 10.78, 95% CI 0.97-120.1). Revision of an initially positive margin was not significantly associated with decreased local recurrence (p = 1).

CONCLUSIONS

In this large cohort of benign and borderline phyllodes tumours, positive resection margins and not margin width at the initial surgery were associated with a increased recurrence. Individualization of decisions regarding margin reexcision is important.

Mammography-based radiomics analysis and imaging features for predicting the malignant risk of phyllodes tumours of the breast

AIM

To determine whether the mammography (MG)-based radiomics analysis and MG/ultrasound (US) imaging features could predict the malignant risk of phyllodes tumours (PTs) of the breast.

MATERIALS AND METHODS

Seventy-five patients with PTs were included retrospectively (39 with benign PTs, 36 with borderline/malignant PTs) and divided into thetraining (n=52) and validation groups (n=23). The clinical information, MG and US imaging characteristics, and histogram features were extracted from craniocaudal (CC) and mediolateral oblique (MLO) images. The lesion region of interest (ROI) and perilesional ROI were delineated. Multivariate logistic regression analysis was performed to determine the malignant factors of PTs. Receiver operating characteristic (ROC) curves were generated, and the area under the curve (AUC), sensitivity, and specificity were calculated.

RESULTS

There was no significant difference found in the clinical or MG/US features between benign and borderline/malignant PTs. In the lesion ROI, variance in the CC view and mean and variance in the MLO view were independent predictors. The AUC was 0.942, sensitivity and specificity were 96.3% and 92%, respectively, in the training group. In the validation group, the AUC was 0.879, the sensitivity was 91.7%, and the specificity was 81.8%. In the perilesional ROI, the AUCs were 0.904 and 0.939, sensitivities were 88.9% and 91.7%, and the specificities were 92% and 90.9% in the training and validation groups, respectively.

CONCLUSIONS

MG-based radiomic features could predict the risk of malignancy of patients with PTs and may be used as a potential tool to differentiate benign and borderline/malignant PTs.

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.

Borderline phyllodes tumor arising in ectopic breast tissue in the axilla: Report of a rare case with brief review of literature

Development of a neoplasm in an ectopic breast is uncommon, while the development of phyllodes tumor in an ectopic breast in the axilla is even rarer. We report a rare case of a 51-year-old female who presented with a complain of swelling and pain in the right axilla with no associated complaints in other organs. Magnetic resonance imaging suggested a possibility of metastatic lymphadenopathy. Complete excision of the right axillary mass was performed and sent for histopathological examination which was examined thoroughly and sections were given. On microscopic examination, stromal proliferation in a leaf-like pattern with mild stromal atypia and focal permeation of borders were seen, and a diagnosis of Ectopic borderline phyllodes tumor in axilla was made, which is extremely rare and needs to be differentiated from its close differentials like fibroadenoma and periductal stromal sarcoma.

Management of phyllodes tumor: A systematic review and meta-analysis of real-world evidence

BACKGROUND

Phyllodes tumor is rare but has a high recurrence rate. Treatment modalities and clinicopathological prognostic factors for recurrence remain unclear. The synthesis of real-world data can enable the integration of sufficient evidence on optimal treatment for this population.

METHODS

We searched PubMed, Embase, and Cochrane Library databases for studies focusing on the management of phyllodes tumor including the surgical margin, different clinicopathological prognostic factors, and postoperative adjuvant radiotherapy versus no radiotherapy.

RESULTS

Fifty-two studies were retrieved. The pooled estimated recurrence rates of benign, borderline, and malignant tumors were 7.1%, 16.7%, and 25.1%, respectively. Surgical margins of 1 mm (odds ratio [OR]: 0.4, 95% confidence interval [CI]: 0.27-0.61) and 1 cm (OR: 0.45, 95% CI: 0.15-0.85) resulted in significantly higher recurrence rates. Postoperative adjuvant radiotherapy significantly reduced the recurrence rate of malignant tumors relative to no radiotherapy (P = 0.034) but did not significantly reduce the recurrence rates of overall and borderline tumors. Regarding clinicopathological features, moderate or severe stromal atypia and hypercellularity, stromal overgrowth, mitotic number of 5, tumor necrosis, tumor border, and margin status were determined as independent prognostic factors for recurrence, except a tumor size of 5 cm.

CONCLUSION

The ideal surgical margin for phyllodes tumor incision should be at least 1 cm in width. Adjuvant radiotherapy reduced the recurrence of malignant tumor. By identifying patients with poor clinicopathological risk factors, surgeons may reduce the recurrence rate of phyllodes tumor.

Incidence and Outcome of Breast Sarcomas in England (2013-2018): An analysis from the National Cancer Registration and Analysis Service

BACKGROUND

Breast sarcomas (BS) are rare cancers originating from mesenchymal breast tissue with a paucity of national population level data detailing their incidence and outcomes.

METHODS

We performed an analysis of data collected by National Cancer Registration and Analysis Service (NCRAS) for patients diagnosed with BS between 2013 and 2018. Chi-square test was used to compare groups. Overall survival (OS) was calculated by Kaplan-Meier. Specialist sarcoma centres (SSC) were defined as centres with a sarcoma multidisciplinary team (MDT).

RESULTS

There were 684 patients with BS (357 malignant phyllodes tumours [PTs], 238 vascular tumours, 93 other morphology) with a median age of 64 (range 14-96); 187 (27%) had received breast radiotherapy for a prior malignancy; 633 (92%) had resection of the tumour within 12 months of diagnosis. Five-year OS was 82%, 54% and 48% in patients with PT, vascular tumours and other sarcomas, respectively, and 55% for those with radiation-induced BS. Patients managed within SSC more frequently had a biopsy prior to surgery 83% versus 72%, p < 0.05) and were less likely to require multiple operations (26% versus 41%, p < 0.05). Tumour stage and grade data were not available.

CONCLUSION

This is the first population series evaluating incidence and outcomes for BS. Patients treated at non-specialist sarcoma centres (NSSCs) are less likely to have a biopsy prior to surgery and more likely to require multiple operations. Based on these observational data, we would recommend all BS are discussed at a sarcoma MDT meeting early in their pathway and surgery to be considered at SSC where possible.

Re-Classification with Outcome Correlation of Previously Diagnosed Malignant Phyllodes Tumors Applying the 2016 Consensus Guidelines

Background. Classification of phyllodes tumors is challenging due unclear diagnostic criteria, recently addressed by consensus review criteria. Herein, we reviewed all malignant phyllodes tumor resections and reclassified them based on the consensus guidelines, correlating with outcome. We hypothesize that application of criteria would result in a significant proportion being "down-graded" to either borderline or benign phyllodes tumor. Methods. Primary resections of malignant phyllodes tumor were reviewed by four AP board-certified, breast fellowship-trained pathologists. Morphologic variables delineated in consensus guidelines (ie stromal cellularity, cellular atypia, tumor border, presence of heterologous elements, presence of stromal overgrowth) were evaluated. Following review, cases were reclassified as benign, borderline, or malignant. Results. Upon reclassification, 20% (5/20) cases were "down-graded" to borderline phyllodes tumor while 80% (15/20) remained malignant phyllodes tumor. Two morphologic features were statistically significant including broadly infiltrating tumor border in 80% (12/15) of malignant phyllodes tumors compared to none in borderline phyllodes tumor (0/5) (p = 0.004) and stromal overgrowth in 67% (10/15) of malignant phyllodes tumor compared to none in borderline phyllodes tumors (0/5) (p = 0.03). Upon review of the pathology reports, 30% (6/20) contained all 5 histomorphologic variables delineated in the consensus review criteria. Malignant phyllodes tumor resulted in five cases with recurrence (33.3%, 5/15) and three cases with metastases (20.0%, 3/15) and borderline phyllodes tumor resulted in one case with recurrence (20.0%, 1/5) and no metastases (0/5). Conclusion. The consensus guidelines for phyllodes tumor are useful for subclassification. We hypothesize that standardize reporting of the histomorphologic variables may lead to better consensus.

Analysis of recurrent molecular alterations in phyllodes tumour of breast: insights into prognosis and pathogenesis

Phyllodes tumour (PT) of breast is a rare biphasic neoplasm. Recent next generation sequencing analyses had revealed novel genetic alterations in PT but lacked a further characterisation of their relationship to different PT features and outcome. Here, using targeted sequencing, we examined a panel of 90 recurrently altered or cancer related genes in 88 PT samples (including 49 benign, 25 borderline and 14 malignant PT). Twenty-three genes showed alterations in at least 8.0% of cases. Alterations were significantly higher with an increasing grade of PT (p=0.033), particularly for copy number alterations. The top ten alterations were TERT promoter (58.0%), MED12 (53.4%), RARA (22.8%), FLNA (19.3%), SETD2 (15.9%), SYNE1 (18.2%), PCLO (15.9%), KMT2D (14.3%), CDKN2A (15.9%) and DNAH11 (14.8%). Alterations in CDKN2A/B, EGFR, TP53, PIK3CA, PTEN and ARID1B (p≤0.039) were associated with a higher grade. Analysing alterations based on common pathways indicated a significant correlation of cell cycle pathway and epigenetic alterations with a higher PT grade (p=0.036 and 0.075 respectively). Interestingly, recurrences were not correlated with tumour grade, but related to the presence of RARA mutation (p=0.011) and the absence of alterations in epigenetic pathway (p=0.031). Analysis of synchronous pair of PT showed more differences in gene mutations with divergent MED12 mutation. By contrast, the recurrent samples showed similar genetic alterations as the primary tumours. In summary, we characterised genetic alterations in PTs of different grades and confirmed the recurrent alterations observed in earlier studies. In addition, current data implicated the roles of cell cycle, epigenetic and RARA changes in PT recurrence and tumourogenesis.

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.

Factors effective on recurrence and metastasis in phyllodes tumors

Background and Aim

Phyllodes tumors (PT) are rare biphasic breast tumors containing stromal mesenchyme and epithelial components. It was classified as benign, borderline, and malignant by the World Health Organization (WHO). Although there is no certainty about the size of the desired margin in the surgery to be applied, a tumor-free area of 1 cm is often targeted. Our study aimed to determine the subtype rates in patients with PT and evaluate the surgical margin, recurrence, and survival times obtained after the surgery.

Patients and Methods

This study was conducted at Seyhan Goverment Hospital and involved the PT patients treated between January 2010 and June 2020. We analyzed PT patients retrospectively. Sixty-one patients with PT were analyzed. In the patient, demographic characteristics, body mass index (BMI), surgical procedures, tumor type, size, mitosis rate, and distance of tumor to surgical margin were evaluated. During follow-up, reoperation, recurrence, metastasis, survival times, and mortality rates were evaluated.

Results

Sixty-one phyllodes breast tumor patients whose histopathology was reported as malignant, borderline, and benign were evaluated and presented in our study. The mean age was 37.84 (15-100), and the BMI was 25.78 (±5.35) mm. Of the 61 patients, 41 (67.2%) were diagnosed with benign phyllodes tumor (BPT), 10 (16.4%) as borderline phyllodes tumor (BLPT), and 10 (16.4%) as malignant phyllodes tumor (MPT).

Conclusions

Preoperative diagnosis of PT can reduce the rate of secondary surgical procedures and the loss of extra breast tissue. A large diameter needle and sufficient number of tissue samples for preoperative core biopsy may increase the rate of accurate diagnosis.

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.

High-Grade Spindle Cell Lesions of the Breast: Key Pathologic and Clinical Updates

Most of the high-grade spindle cell lesions of the breast are malignant phyllodes tumors (MPTs), spindle cell carcinomas (SpCCs), and matrix-producing metaplastic breast carcinomas (MP-MBCs). MPTs have neoplastic spindle stromal cells and a classic leaf-like architecture with subepithelial stromal condensation. MPTs are often positive for CD34, CD117, and bcl-2 and are associated with MED12, TERT, and RARA mutations. SpCCs and MP-MBCs are high-grade metaplastic carcinomas, whereas neoplastic epithelial cells become spindled or show heterologous mesenchymal differentiation, respectively. The expression of epithelial markers must be evaluated to make a diagnosis. SAS, or rare metastatic spindle cell tumors, are seen in the breast, and clinical history is the best supporting evidence. Surgical resection is the standard of care.

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.

Under- and Normal-Weight Patients Are More Susceptible to Recurrence of Phyllodes Tumor

Purpose

Phyllodes tumors (PTs) of the breast are rare fibroepithelial neoplasms, and factors associated with the recurrence of PTs are poorly understood. This study sought to identify clinicopathological factors associated with the recurrence of PTs.

Method

From January 2009 to December 2019, we identified 100 patients who underwent definitive surgery for PT. Clinicopathological risk factors associated with the recurrence of PT were assessed.

Results

The median age of the patients was 44 y (range, 19–62 y), and the median tumor size was 4 cm (0.8–30 cm). At a median follow-up of 26.7 mo (0–103 mo), 22 of the 100 patients experienced local recurrence. In the univariate and multivariate analyses, body mass index ≥ 23 kg/m² (P = 0.042 in the univariate analysis; P = 0.039 in the multivariate analysis), tumor size ≥ 5 cm (P = 0.006 in the univariate analysis; P = 0.036 in the multivariate analysis), and the presence of stromal overgrowth (P = 0.032 in the univariate analysis; P = 0.040 in the multivariate analysis) were associated with an increased risk of local recurrence. Resection margins and grade were not associated with local recurrence.

Conclusion

Normal- or underweight patients and those with larger tumor sizes were more prone to local recurrence. Further larger, multicenter studies with a long-term follow-up are required.

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.

MED12 exon 2 and TERT promoter mutations in primary and recurrent breast fibroepithelial lesions

The genetic alterations in the recurrent breast fibroepithelial tumors are poorly understood. In the present study, we aimed to investigate mediator protein complex subunit 12 (MED12) exon 2 and telomerase reverse transcriptase (TERT) promoter mutations in a series of primary and recurrent fibroepithelial tumors. Sanger sequencing for MED12 exon 2 and TERT promoter was performed in 26 pairs of primary and recurrent fibroepithelial tumors (19 pairs of phyllodes tumors and seven pairs of fibroadenomas). The relationship between the genotypes and clinicopathological variables was also analyzed. MED12 mutation was identified in 19 primary tumors (12 phyllodes tumors and 7 fibroadenomas) and 17 recurrences (14 phyllodes tumors and three fibroadenomas). Most recurrent phyllodes tumors retained the original MED12 variants (17/19). Six recurrent fibroadenomas showed different MED12 variants from their paired primary tumors (6/7). TERT promoter mutation was identified in 13 primary phyllodes tumors (13/19) and 15 recurrent phyllodes tumors (15/19). However, it was only identified in one primary fibroadenoma (1/7). Recurrent phyllodes tumors often retained the original MED12 and TERT promoter mutations, while recurrent fibroadenomas often acquired new MED12 mutations. Our findings suggest that recurrent phyllodes tumors may be "true recurrence," and TERT mutant "benign fibroepithelial tumors" should be treated as phyllodes tumors.

Recurrent Giant Malignant Phyllodes Tumor of the Breast

Phyllodes tumors (PTs) are rare fibroepithelial neoplasms of the breast. They have a proliferating stromal component that can be graded as benign, borderline, and malignant. In addition, they are associated with an increased risk of local recurrence and distant metastasis. The authors hereby present a case report of a 34-year-old woman with recurrent malignant PT with an increasing aggressiveness. There were two recurrences of giant tumors that consumed the entire right breast, which developed over a three-year period. The final surgical treatment was a total extirpation of the tumor with subsequent plastic reconstruction using a cutaneous flap from the region of the latissimus dorsi muscle. The patient died three months after the last recurrence due to multiorgan failure.

Aggressive malignant phyllodes tumor of breast with omental metastases - A case report

Distant metastasis from malignant Phyllodes tumour (PT) is rare. They generally metastasize to the lung, bone, pleura, and liver. We present a very rare case of a 25-year-old woman with intraabdominal metastases from malignant phyllodes tumour of the breast. She presented with left breast lump and the biopsy was Phyllodes tumour. She underwent a two staged surgery; left modified radical mastectomy followed by left latissimus dorsi musculocutaneous flap cover. She received adjuvant radiation therapy to left chest wall. Following which she developed intrabdominal mass which was proven to be metastasis from Phyllodes tumour. She was then advised palliative chemotherapy. Malignant Phyllodes with distant metastases has a dismal prognosis. We propose it is preferable to have a CT Thorax and Abdomen as a staging workup for patients with malignant PT to identify those with poor prognosis.

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.

Phyllodes Tumors: A Scoping Review of the Literature

PURPOSE

Phyllodes tumors are rare tumors of the breast, with most literature being retrospective with limited guidelines on the management of these patients. Scoping review was performed to highlight themes and gaps in the available literature.

METHODS

A scoping review of the literature was performed as per PRISMA-ScR guidelines with titles, abstracts, and full texts reviewed in duplicate. Data were abstracted and summarized in categories of diagnostics, surgical management, adjuvant therapies, treatment of recurrence, and surveillance. Quality assessment was performed for each paper.

RESULTS

The search identified 4498 references, 434 full-text papers were reviewed, and 183 papers were included. Ultrasound, magnetic resonance imaging, and core needle biopsy are valuable preoperative diagnostics tools. Pathology reporting should include stromal overgrowth, stromal cellularity, nuclear atypia, mitotic rate, borders, and presence of heterologous elements. Ki67 may have a role in grading and prognosticating. Breast conservation is safe in all grades of phyllodes but may be associated with increased local recurrence in malignant phyllodes. Surgical margins should depend on grade. Axillary node positivity rate is very low, even with clinically enlarged lymph nodes. Adjuvant radiation is a useful tool to decrease local recurrence in malignant phyllodes tumors, tumors > 5 cm, age < 45 years, close margins, and breast conservation. There is no evidence supporting adjuvant chemotherapy. Recurrence can be managed with repeat wide excision; however, mastectomy is associated with lower re-recurrence. Surveillance protocols are variable in the literature.

CONCLUSIONS

There is heterogeneity in the literature on phyllodes tumors. Consensus guidelines based on the literature will help provide evidence-based care.

Genetic differences between benign phyllodes tumors and fibroadenomas revealed through targeted next generation sequencing

Breast fibroepithelial lesions are biphasic tumors which comprise the common benign fibroadenomas (FAs) and the rarer phyllodes tumors (PTs). This study analyzed 262 (42%) conventional FAs, 45 (7%) cellular FAs, and 321 (51%) benign PTs contributed by the International Fibroepithelial Consortium, using a previously curated 16 gene panel. Benign PTs were found to possess a higher number of mutations, and higher rates of cancer driver gene alterations than both groups of FAs, in particular MED12, TERT promoter, RARA, FLNA, SETD2, RB1, and EGFR. Cases with MED12 mutations were also more likely to have TERT promoter, RARA, SETD2, and EGFR. There were no significant differences detected between conventional FAs and cellular FAs, except for PIK3CA and MAP3K1. TERT promoter alterations were most optimal in discriminating between FAs and benign PTs. Our study affirms the role of sequencing and key mutations that may assist in refining diagnoses of these lesions.