Phyllodes tumours of the breast: a consensus review

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.

Malignant phyllodes tumor of the breast with predominant osteosarcoma and chondrosarcomatous differentiation: a rare case report and review of literature

Background

Phyllodes tumors (PTs), which account for less than 1% of mammary gland tumors, composed of both epithelial and stromal components. If a malignant heterologous component is encountered, PT is considered malignant. Malignant phyllodes tumors (MPTs) only account for 8% to 20% of PTs. We report a case of MPT with osteosarcoma and chondrosarcoma differentiation and review the literature to discuss the differential diagnosis and therapy.

Case presentation

A 59-year-old Chinese woman come to our hospital because of a palpable mass she had had for 1 months in the left breast. Preoperative core needle biopsy (CNB) was performed on the left breast mass on January 11, 2023. Pathological diagnosis was malignant tumor, the specific type was not clear. Mastectomy and sentinel lymph node biopsy of the left breast was performed. No metastasis was found in 3 sentinel lymph nodes identified by carbon nanoparticles and methylene blue double staining. Heterologous osteosarcoma and chondrosarcomatous differentiation of phyllodes tumor were observed. Immunohistochemistry: spindle tumor cells ER(-), PR(-), HER-2(-), CK-pan(-), CK7(-), CK8(-), SOX10(-), S100(-), and MDM2(-), CK5/6(-), P63(-), P40(-) were all negative. CD34:(+), SATB2(+), P53(90% strong), CD68 (+), Ki-67(LI: about 60%). No ductal carcinoma in situ was found in the breast. Fluorescence in situ hybridization (FISH) indicated USP6 was negatively expressed on formalin-fixed, paraffin-embedded (FFPE) tissue sections.

Conclusion

MPTs are rare, and heterologous differentiation in MPTs is exceedingly rare. It could be diagnosed by pathology when metaplastic carcinoma, primary osteosarcoma, or myositis ossificans were excluded. This case could help clinicians to improve the prognosis and treatment of this disease.

Recurrent giant phyllodes tumor of the breast: a case report

Background

Phyllodes tumors (PTs) account for 0.3-1.0% of all breast tumors and often occur in women aged 35 to 55. They are similar to giant fibroadenomas. PTs are famous for local recurrence. No more than 10% of PTs grow larger than 10 cm. The National Comprehensive Cancer Network (NCCN) guidelines recommend extensive resection with a margin of ≥1 cm for PTs, which is much larger than that required for breast cancer. Positive resection margin is associated with recurrence. However, little is known about whether all subtypes really require radical tumor negative resection margins.

Case Description

We report on a 49-year-old woman with a giant borderline PT in her left breast. The tumor was greater than 10.5 cm × 7.0 cm. She had a bilateral benign PT excision in January 2014 and a left benign PT excision in December 2018. A chest computerized tomography (CT) scan and abdomen ultrasound did not reveal distant metastasis. Therefore, left breast mastectomy was performed. Wound healing was satisfactory. Pathological and immunohistochemistry findings showed a borderline PT.

Conclusions

As the rare tumor of the breast, PTs pose a great challenge for surgeons. The initial evaluation of PTs relies on a triple evaluation of clinical, radiological, and histological examination. Local recurrence of PTs is more common than distant metastasis. The histology of recurrent tumors is usually identical to that of the primary tumor, or has a tendency to malignancy. Although most surgeons are uncomfortable with PTs with a positive margin, it is reasonable to adopt a "watchful waiting" strategy for benign PTs. The current recommendation that PTs should be extensively resected regardless of tumor size might be revised.

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.

Benign phyllodes tumour in a transgender woman receiving hormonal therapy

We present a case of a transwoman taking hormonal feminisation therapy for over 20 years, who underwent surgical excision of a benign phyllodes tumour of the breast. Hormones progesterone and oestrogen act on breast epithelium to increase proliferation. For ciswomen, endogenous and exogenous oestrogen exposure over a lifetime is associated with increased risk for certain benign and malignant breast pathologies. Transwomen taking hormonal therapy may also be at an increased risk of breast disease.

Surgical margins and prognosis of borderline and malignant phyllodes tumors

PURPOSE

To investigate the optimal surgical margin and prognostic risk factors for borderline and malignant phyllodes tumors (PTs).

METHODS

A retrospective analysis was conducted on patients with borderline and malignant PTs at our hospital from 2011 to 2022. Univariate and multivariate Cox proportional hazard models were employed to analyze the effects of various variables on local recurrence-free survival (LRFS) and disease-free survival (DFS).

RESULTS

This study comprised 150 patients, 85 classified as borderline and 65 as malignant. During a median follow-up of 66 months (range: 3-146 months), 34 cases (22.7%) experienced local recurrence, 9 cases (6.0%) exhibited distant metastasis, and 7 cases (4.7%) resulted in death. Irrespective of the histological subtypes, patients with surgical margins ≥ 1 cm exhibit significantly higher 5-year LRFS and 5-year DFS rates compared to those with margins < 1 cm. Among patients with initial margins < 1 cm, LRFS (P = 0.004) and DFS (P = 0.003) were improved in patients reoperated to achieve margins ≥ 1 cm. Surgical margin < 1 cm (HR = 2.567, 95%CI 1.137-5.793, P = 0.023) and age < 45 years (HR = 2.079, 95%CI 1.033-4.184, P = 0.040) were identified as independent risk factors for LRFS. Additionally, surgical margin < 1 cm (HR = 3.074, 95%CI 1.622-5.826, P = 0.001) and tumor size > 5 cm (HR = 2.719, 95%CI 1.307-5.656, P = 0.007) were determined to be independent risk factors for DFS.

CONCLUSIONS

A negative surgical margin of at least 1 cm (with secondary resection if necessary) should be achieved for borderline and malignant PTs. Tumor size > 5 cm and age < 45 years were predictive of recurrence, suggesting multiple therapy modalities may be considered for these high-risk patients.

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.

Primary malignant phyllodes tumors of the breast: A retrospective analysis from a referral center

BACKGROUND

The treatment for primary malignant phyllodes tumors of the breast (B-MPT) consists of wide local excision with negative margins (≥1 cm). However, because of their rarity, prognostic factors, type of surgery and adjuvant treatments are still a matter of debate.

METHODS

We conducted a single-center retrospective study to describe outcomes and prognostic factors of patients with primary B-MPT, who underwent breast surgery from January 2000 to December 2021. The primary endpoint was the cumulative incidence of any recurrence. Secondary endpoints were the cumulative incidences of distant and local recurrences.

RESULTS

131 patients were included, of whom all received surgery, 5 adjuvant anthracycline-based chemotherapy and 15 radiation therapy. After a median follow-up of 6.4 years, the cumulative incidences at 5-years of any, local and distant recurrences were of 26% (95% Confidence Interval [CI], 4-34%), 16% (95%CI, 10-24%) and 10% (95%CI, 5.3-16%), respectively. Tumor size ≥ 5 cm was associated with higher distant recurrences (p = 0.05); instead, among small tumors (<5 cm), distant recurrences were higher in those with heterologous differentiation and/or multifocal disease (p = 0.06). Type of breast surgery (mastectomy vs. lumpectomy/excision) was not found to be significantly associated with distant (p = 0.32) or local (p = 0.17) recurrence, even after controlling local recurrence incidence for negative pathologic prognostic factors (p = 0.17).

CONCLUSIONS

The natural history of B-MPT is burdened by local and distant recurrences. Pathologic prognostic factors (i.e., tumor size, heterologous differentiation and multifocal disease) more than the type of wide breast surgery (mastectomy vs. lumpectomy) seem to represent the most significant prognostic factor for recurrences.

Multidisciplinary Management of Phyllodes Tumours and Breast Sarcoma: A Cross-sectional Survey of Clinical Practice across the UK and Ireland

AIMS

Phyllodes tumours and breast sarcomas are uncommon tumours and their rarity poses significant challenges in diagnosis and management. This cross-sectional study was conducted to evaluate the multidisciplinary clinical practice for these tumours across the UK and Ireland, with the aim of identifying gaps in knowledge and providing direction for establishing national guidelines.

MATERIALS AND METHODS

An international survey was adapted and circulated to breast and/or sarcoma surgeons and oncologists in the UK and Ireland through national organisations. Multidisciplinary team (MDT) responses were analysed anonymously.

RESULTS

Twenty-eight MDTs participated in this study, predominately from high-volume units (85.5%). Although only 43% of the surveyed units were part of a trust that holds a sarcoma MDT, 68% of units managed malignant phyllodes and angiosarcoma, whereas 64.5% managed soft-tissue sarcoma of the breast. Across all subtypes, axillary surgery was recommended by 14-21% of the MDTs and the most recommended resection margins for breast surgery were 'no tumour on ink' in benign phyllodes (39%) and 10 mm in the remaining subtypes (25-29%). Immediate breast reconstruction was supported by 11-18% of MDTs for breast sarcoma subtypes, whereas 36% and 32% advocated this approach in benign and borderline phyllodes tumours, respectively. Adjuvant radiotherapy and chemotherapy were recommended by up to 29% and 11% of the MDTs, respectively.

CONCLUSION

The results of this study demonstrate a wide variation in clinical practice across the surveyed MDTs. As only 28 MDTs participated in our study, with under-representation from low-volume units, our results might be an underestimation of the variability in practice across the UK and Ireland. This multi-institutional study sheds light on controversial aspects in the management of phyllodes tumours and breast sarcoma, identifies the need for national guidelines to inform best practice, and calls for the centralisation of the management of breast sarcoma within specialist centres.

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.

Borderline Phyllodes Tumor in a Child

Phyllodes tumor (PT) is considered a rare fibroepithelial tumor. Very few series have been reported in children and adolescents. Based on histopathological features, it can be classified as benign, borderline, or malignant, with the latter having a more aggressive clinical behavior. We report the case of a 10-year-old female who began with an asymptomatic mobile right breast mass. An initial fine needle biopsy (FNB) concluded fibroadenoma (FA). Months later, the mass kept growing, with the appearance of pain and nipple discharge. Benign PT was demonstrated in a new biopsy. A total mastectomy was performed. The post-surgical histopathological examination was compatible with a borderline PT. The patient is now symptom-free and with no signs of relapse. Not all breast masses in the pediatric or adolescent age bracket are FA. Attention is warranted when the clinical behavior does not follow the usual outline. PT has to be considered as a possible diagnosis and treated accordingly.

Periductal Stromal Tumor of the Breast with a TERT Promoter Mutation: First Case Report with Comprehensive Molecular Analysis

The molecular pathogenesis of breast fibroepithelial tumors continues to be elucidated. Recently, highly recurrent MED12 mutations arising in exon 2 at codon 44 were discovered in fibroadenomas and phyllodes tumors. In addition, a high prevalence of TERT promoter mutations in two hotspots (124 and 126 bp upstream from the translation start site) was discovered in up to 65% of phyllodes tumors. Breast periductal stromal tumors are a potentially distinct category of fibroepithelial lesions that are exceptionally rare with controversial classification and pathogenesis. Herein, we report the first comprehensive molecular genetic workup of a breast periductal stromal tumor that harbored a TERT promoter -124C > T mutation, supporting a relation to phyllodes tumors.

A Comprehensive Review of Breast Fibroadenoma: Correlating Clinical and Pathological Findings

Breast fibroadenomas, common benign conditions, exhibit distinct clinical and histopathological features. This review highlights clinical presentation and histology correlations, providing insights for healthcare providers. Palpable masses, pain, and changes in breast appearance align with glandular and stromal components, emphasizing accurate diagnosis. Mammography, ultrasound, and MRI guide tailored treatment decisions. Challenges in differentiating atypical fibroadenomas highlight the need for meticulous histopathological evaluation. Clinical implications stress patient-centered care, shared decision-making, and ongoing follow-up. Future research focuses on genetic investigations and long-term studies. A multidisciplinary approach to breast fibroadenomas ensures comprehensive care for improved outcomes in both medical and emotional aspects.

Precise diagnosis of breast phyllodes tumors using Raman spectroscopy: Biochemical fingerprint, tumor metabolism and possible mechanism

BACKGROUND

Breast fibroadenomas and phyllodes tumors are both fibroepithelial tumors with comparable histological characteristics. However, rapid and precise differential diagnosis is a tough point in clinical pathology. Given the tendency of phyllodes tumors to recur, the difficulty in differential diagnosis with fibroadenomas leads to the difficulty in optimal management for these patients.

METHOD

In this study, we used Raman spectroscopy to differentiate phyllodes tumors from breast fibroadenomas based on the biochemical and metabolic composition and develop a classification model. The model was validated by 5-fold cross-validation in the training set and tested in an independent test set. The potential metabolic differences between the two types of tumors observed in Raman spectroscopy were confirmed by targeted metabolomic analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

A total of 204 patients with formalin-fixed paraffin-embedded (FFPE) tissue samples, including 100 fibroadenomas and 104 phyllodes tumors were recruited from April 2014 to August 2021. All patients were randomly divided into the training cohort (n = 153) and the test cohort (n = 51). The Raman classification model could differentiate phyllodes tumor versus fibroadenoma with cross-validation accuracy, sensitivity, precision, and area under curve (AUC) of 85.58 % ± 1.77 %, 83.82 % ± 1.01 %, 87.65 % ± 4.22 %, and 93.18 % ± 1.98 %, respectively. When tested in the independent test set, it performed well with the test accuracy, sensitivity, specificity, and AUC of 83.50 %, 86.54 %, 80.39 %, and 90.71 %. Furthermore, the AUC was significantly higher for the Raman model than that for ultrasound (P = 0.0017) and frozen section diagnosis (P < 0.0001). When it came to much more difficult diagnosis between fibroadenoma and benign or small-size phyllodes tumor for pathological examination, the Raman model was capable of differentiating with AUC up to 97.45 % and 95.61 %, respectively. On the other hand, targeted metabolomic analysis, based on fresh-frozen tissue samples, confirmed the differential metabolites (including thymine, dihydrothymine, trans-4-hydroxy-l-proline, etc.) identified from Raman spectra between phyllodes tumor and fibroadenoma.

SIGNIFICANCE AND NOVELTY

In this study, we obtained the molecular information map of breast phyllodes tumors provided by Raman spectroscopy for the first time. We identified a novel Raman fingerprint signature with the potential to precisely characterize and distinguish phyllodes tumors from fibroadenoma as a quick and accurate diagnostic tool. Raman spectroscopy is expected to further guide the precise diagnosis and optimal treatment of breast fibroepithelial tumors in the future.

Management of Benign Phyllodes Tumors: A Dutch Population-Based Retrospective Cohort Between 1989 and 2022

BACKGROUND

Phyllodes tumors (PTs) are rare tumors of the breast. The current National Comprehensive Cancer Network (NCCN) guidelines recommend excision of benign PTs, accepting close or positive margins. Controversy about the optimal treatment for benign PTs remains, especially regarding the preferred margin width after surgical excision and the need for follow-up evaluation.

METHODS

A nationwide retrospective study analyzed the Dutch population from 1989 to 2022. All patients with a diagnosis of benign PT were identified through a search in the Dutch nationwide pathology databank (Palga). Information on age, year of diagnosis, size of the primary tumor, surgical treatment, surgical margin status, and local recurrence was collected.

RESULTS

The study enrolled 1908 patients with benign PT. The median age at diagnosis was 43 years (interquartile range [IQR], 34-52 years), and the median tumor size was 30 mm (IQR, 19-40 mm). Most of the patients (95%) were treated with breast-conserving surgery (BCS). The overall local recurrence rate was 6.2%, and the median time to local recurrence was 31 months (IQR, 15-61 months). Local recurrence was associated with bilaterality of the tumor (odds ratio [OR], 4.91; 95% confidence interval [CI], 2.95-28.30) and positive margin status (OR, 2.51; 95% CI 1.36-4.63). The local recurrence rate was 8.9% for the patients with positive excision margins and 4.0% for the patients with negative excision margins. Notably, for 27 patients (22.6%) who experienced a local recurrence, histologic upgrading of the recurrent tumor was reported, 7 (5.9%) of whom had recurrence as malignant lesions.

CONCLUSIONS

This nationwide series of 1908 patients showed a low local recurrence rate of 6.2% for benign PT, with higher recurrence rates following positive margins.

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).

The Genetic Landscape of Fibroepithelial Lesions of the Breast

Fibroepithelial lesions of the breast encompass a broad spectrum of lesions from fibroadenomas and their variants to phyllodes tumors, including their clinical range of benign, borderline, and malignant. Classification of this spectrum of neoplasms has historically and currently been based purely on morphology, although the nomenclature has shifted over the years largely due to the significant histologic overlap that exists primarily within the cellular fibroadenomas to borderline malignant phyllodes tumor categories. A review of the current diagnostic challenge, proposed ancillary studied and their value in prognostic significance, is provided. This article highlights the most recent molecular and genetic findings as well as the limitations of the studies, in the context of practical and available applications for the diagnostician and managerial implications for the clinician.

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.

Immunohistochemistry in the Diagnosis and Classification of Breast Tumors

CONTEXT.—

In the clinical practice of breast pathology, immunohistochemistry (IHC) of different markers is widely used for the diagnosis and classification of breast lesions.

OBJECTIVE.—

To provide an overview of currently used and recently identified IHC stains that have been implemented in the field of diagnostic breast pathology.

DATA SOURCES.—

Data were obtained from literature review and clinical experience of the authors as breast pathologists.

CONCLUSIONS.—

In the current review, we summarize the common uses of IHC stains for diagnosing different types of breast lesions, especially invasive and noninvasive breast lesions, and benign and malignant spindle cell lesions. In addition, the cutting-edge knowledge of diagnostic carcinoma markers will lead us to further understand the different types of breast carcinoma and differentiate breast carcinomas from other carcinomas of similar morphology. Knowing the strengths and limitations of these markers is essential to the clinical practice of breast pathology.

Phyllodes Tumors of the Breast: Canadian National Consensus Document Using Modified Delphi Methodology

PURPOSE

Phyllodes tumors are rare breast neoplasms with limited prospective data to guide treatment, leading to heterogeneous management of this disease. We developed National consensus statements using modified Delphi methodology including patients and practitioners across Canada.

METHODS

Statements were developed based on a literature review. Two iterations of surveys were distributed with a planned virtual consensus meeting. Panelists were invited from surgery, radiation oncology, medical oncology, pathology, radiology, and plastic surgery.

RESULTS

Twenty-three participants attended the virtual conference. One hundred statements regarding diagnostics, pathology, surgical planning, adjuvant therapies, recurrence, surveillance, and patient support were approved with an a priori defined consensus of ≥ 80%. Two tables on locoregional management were developed and approved. The management of borderline phyllodes tumors was a source of uncertainty, and recommendations reflect the lack of evidence in this rare presentation.

CONCLUSION

A consensus document containing all approved statements for the care and management of phyllodes tumors was developed to help guide practice and future research.

Case Report: A 13-year-old adolescent diagnosed as malignant phyllodes tumor combined with rhabdomyosarcoma differentiation

Phyllodes tumor (PT) is an infrequent type of breast neoplasm, constituting a mere 0.5%-1.5% of the entirety of breast tumors. The malignant phyllodes tumor (MPT) comprises only 15% of all phyllodes tumors, and its transformation into rhabdomyosarcoma (RMS) is exceedingly rare in clinical practice. Given its insensitivity to chemotherapy and radiotherapy, treatment options for MPT patients are limited, leaving complete surgical resection as the only option. Therefore, it is imperative to investigate the effective utilization of the heterogeneous differentiation characteristics of MPT to expand treatment alternatives for these patients. In this case report, we represent a 13-year-old adolescent diagnosed with giant breast MPT with RMS differentiation and pulmonary metastasis. The initial step in the treatment process involved radical surgical resection, followed by the administration of four cycles of VDC/IC chemotherapy, which is widely recognized as the standard chemotherapy for RMS. Regrettably, the delay in initiating chemotherapy resulted in minimal observable changes in the size of the pulmonary metastatic nodule. Additionally, a comprehensive literature review on the characterization of MPT with heterogeneous differentiation was conducted to enhance comprehension of the diagnosis and treatment of this uncommon disease in clinical practice. Meanwhile, this case also reminds the doctors that when we diagnose a patient as MPT, it is crucial to consider its heterogenous nature and promptly initiate adjuvant treatment. By targeting the differentiation element of MPT, it becomes feasible to overcome the previously perceived limitation of surgical intervention as the sole treatment option.

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

CONTEXT.—

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

OBJECTIVE.—

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

DATA SOURCES.—

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

CONCLUSIONS.—

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

The phyllodes menace-Variation in course, therapy, and appearance of phyllodes tumors in a case series of three patients

Key Clinical Message

Early and complete surgical resection is the most important therapeutic and diagnostic measure. Adjuvant radiation is suggested for malign phyllode tumors, phyllode tumors larger than 10 cm or those with a low distance to the resection margins.

Abstract

Phyllodes tumors are rare fibroepithelial tumors of the breast. Histologically, they are usually classified as benign, borderline or malignant, though these classifications do not necessarily reflect the clinical course of the disease. These tumors may stay undetected for years, or show sudden and rapid progression. There is currently no consistent therapy recommendation based upon histological findings, the localization of the tumor and/or whether it is recurrent. Using the examples of three patients, we show how courses and therapy may differ widely, and discuss this in the context of the current state of the literature.

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.

Approach to the growing breast lump during lactation

Physiological changes during pregnancy and lactation result in increased lumpiness of the breast. This makes the evaluation of the breast challenging. Although most self-detected lumps, during this period, tend to be benign, the priority in these patients is to exclude tumours that may require prompt management. We present a case of phyllodes tumour that occurred during lactation and discussed the resultant pitfalls that may occur during the triple assessment of a breast lump in a lactating mother.

Breast development and disorders in children and adolescents

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

A Large Phyllodes Tumor With Axillary Lymph Node Involvement: A Case Report

Malignant phyllodes tumors of the breast are uncommon and complex to treat. This case involves a 39-year-old woman with a rapidly growing mass in her right breast measuring 32cm. The patient underwent a bilateral mastectomy with a right sentinel node biopsy and right chest wall reconstruction. The final pathology of the tumor revealed a malignant phyllodes tumor, with one of two right axillary lymph nodes positive for metastatic phyllodes tumor. Malignant phyllodes tumors should be taken into consideration in any rapidly growing breast mass. Further studies analyzing the treatment of malignant phyllodes tumors are necessary to reduce the risk of tumor recurrence and metastasis.

Machine Learning-Based Ultrasound Texture Analysis in Differentiation of Benign Phyllodes Tumors from Borderline-Malignant Phyllodes Tumors

PURPOSE

 Phyllodes tumors (PTs) are uncommon fibroepithelial breast lesions that are classified as three different forms as benign phyllodes tumor (BPT), borderline phyllodes tumor (BoPT), and malignant phyllodes tumor (MPT). Conventional radiologic methods make only a limited contribution to exact diagnosis, and texture analysis data increase the diagnostic performance. In this study, we aimed to evaluate the contribution of texture analysis of US images (TAUI) of PTs in order to discriminate between BPTs and BoPTs-MPTs.

METHODS

 The number of patients was 63 (41 BPTs, 12 BoPTs, and 10 MPTs). Patients were divided into two groups (Group 1-BPT, Group 2-BoPT/MPT). TAUI with LIFEx software was performed retrospectively. An independent machine learning approach, MATLAB R2020a (Math- Works, Natick, Massachusetts) was used with the dataset with p < 0.004. Two machine learning approaches were used to build prediction models for differentiating between Group 1 and Group 2. Receiver operating characteristics (ROC) curve analyses were performed to evaluate the diagnostic performance of statistically significant texture data between phyllodes subgroups.

RESULTS

 In TAUI, 10 statistically significant second order texture values were identified as significant factors capable of differentiating among the two groups (p < 0.05). Both of the models of our dataset make a diagnostic contribution to the discrimination between BopTs-MPTs and BPTs.

CONCLUSION

 In PTs, US is the main diagnostic method. Adding machine learning-based TAUI to conventional US findings can provide optimal diagnosis, thereby helping to choose the correct surgical method. Consequently, decreased local recurrence rates can be achieved.

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.

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.

Prevalence, Impact, and Diagnostic Challenges of Benign Breast Disease: A Narrative Review

Benign breast diseases, which are commonly seen in clinical practice, have various clinical presentations and implications, as well as management strategies. This article describes common benign breast lesions, presentations of these lesions, and typical radiographic and histologic findings. Also included in this review are the most recent data and guideline-based recommendations for the management of benign breast diseases at diagnosis, including surgical referral, medical management, and ongoing surveillance.

Clinical outcomes and biomarkers of phyllodes tumors of the breast: A single-center retrospective study

PURPOSE

Phyllodes tumors (PTs) are rare neoplasms with a certain risk of recurrence and/or metastasis. In clinical practice, there is a lack of high-quality clinical studies and unified guidelines to guide the treatment.

MATERIALS AND METHODS

All malignant and recurrence/metastasis PTs were retrospectively collected, which were diagnosed from 2008 to 2022.

RESULTS

A total of 82 patients were enrolled, including 69 malignant and 13 borderline tumors. 96.3% (79/82) received surgical treatment. During a median follow-up of 55.5 months, 20 patients (20/82, 24.4%) had distant metastasis (DM), while 32 (32/82, 39.0%) had local recurrence (LR). Univariate analysis showed the survival of PTs was associated with surgical methods (p < 0.001), tumor size (p = 0.026), and biological behavior (p = 0.017), but not age at diagnosis. In relapsed borderline PTs, we did not find deaths due to disease progression. Patients with DM were all malignant PTs, with disease-progression occurring within 3 years in more than 80% of patients. Among salvage treatments, the combination of antiangiogenic drugs improved the prognosis to some extent, with a significant increase in mPFS (2.77 vs. 1.53 months), but no significant statistical results were obtained (p = 0.168). Lactate dehydrogenase (LDH) was an independent predictor of the prognosis for malignant PTs (p = 0.001, HR = 1.203, 95%CI, 1.082-1.336).

CONCLUSION

Borderline PTs rarely metastasize, and even if LR occurs, surgical resection can lead to long-term survival. In metastatic phyllodes tumors (MPT), systemic therapy is not effective, but antiangiogenic drugs may prolong survival. LDH is an independent prognostic factor for malignant PTs to identify high-risk tumors.

Breast Phyllodes Tumor: A Tumor With Unpredictable Clinical Behavior

Phyllodes tumors are uncommon biphasic breast tumors with a wide range of clinical behaviors. The distinction between a phyllodes tumor and a fibroadenoma can be difficult. The diagnosis of phyllodes tumor should be suspected in all women who present with a rapidly growing breast lump. Based on the histological characteristics, the World Health Organization (WHO) classifies phyllodes tumors as benign, borderline, or malignant. The risk of recurrence and metastatic potential varies based on histological features. Wide excision or mastectomy is the standard of care ensuring histologically clear margins. Despite the grading criteria defined by the WHO, the management of phyllodes tumors continues to be a challenge. We report the case of a 48-year-old woman who presented to the emergency department with a large and ulcerated phyllodes tumor of the left breast. The tumor size did not allow conservative surgery. The final diagnosis of a borderline phyllodes tumor was made, and, in this case, the patient did not undergo adjuvant treatment.

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.

Osteosarcoma Originating From a Malignant Phyllodes Tumor: A Case Report of a Rare Malignancy

Fibroepithelial tumors are common in the breast; however, the frequency of malignancy is much less as compared to the epithelial counterpart. Malignant phyllodes are infrequent, and the proportion undergoing heterologous differentiation is very rare. Extensive sampling and astute examination are of utmost importance so as not to miss this lesion. The prognosis of these tumors is worse compared to cases where no heterologous transformation is seen.

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.

Rethinking on the management strategy of malignant phyllodes tumor of the breast: An analysis based on the SEER database

Malignant phyllodes tumor of the breast (MPTB) is a rare breast neoplasm that has a high recurrence rate and its optimal treatment strategies remain controversial. Our study used the most up-to-date database to determine prognostic factors that predict cancer-specific survival (CSS) and to evaluate the effects of different treatment strategies for MPTB. We performed a retrospective cohort study using the National Cancer Institute's Surveillance, Epidemiology, and End Results database. Women who were diagnosed with MPTB from 2000 to 2019 were included. Kaplan-Meier method and Cox proportional hazards regressions were used to evaluate the prognostic power of variables on CSS. A total of 1902 women with MPTB were included in the study, with a median follow-up duration of 87.5 months. Age was found not to independently predict CSS in patients with tumors larger than 10 cm (P = .235). Mastectomy was performed on a total of 898 (47.2%) patients including 210 women (23.4%) undergoing radiotherapy after surgery. Mastectomy showed worse CSS when compared with breast-conserving surgery in patients with tumors smaller than 10 cm. Patients undergoing radiotherapy were not inferior to non-radiotherapy patients on CSS when patients were stratified by tumor size. Breast-conserving surgery showed survival benefits for patients with small tumors (T1 and T2). Patients with radiotherapy were not inferior to non-radiotherapy patients on CSS. Treatment of patients with MPTB should be carefully selected based on different tumor sizes.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Race-Related Differences in the Clinical Presentation and Histopathologic Features of Phyllodes Tumor

BACKGROUND

Phyllodes tumor (PT) is a rare fibroepithelial lesion of the breast with variable malignant potential. Black women have a higher incidence of a related benign tumor, fibroadenoma, but there are limited epidemiological data on PT. The aim of our study was to evaluate race-related differences in the clinicopathologic features and outcomes of PT.

METHODS

Our institutional pathology database was queried for breast specimen reports from 01/2009 to 10/2019 to identify patients with a pathologic diagnosis of PT. Chart review and detailed slide review were performed to obtain clinical and histopathologic variables, respectively.

RESULTS

Among twelve patients, two had malignant PT, three had borderline PT, and seven had benign PT. All patients with malignant and borderline PT were black, compared with 29% of those with benign PT. There were no apparent race-related differences in specific histopathologic features among black vs. non-black women with benign PT. Malignant and borderline PT were relatively larger than benign PT, with mean tumor sizes of 9.0 cm (standard deviation [SD] 4.7 cm), 12.2 cm (SD 9.4 cm), and 5.4 cm (SD 5.8 cm), respectively. Two women had a local recurrence, both of whom were black.

DISCUSSION

In this single-institution retrospective study, we observed disproportionate rates of aggressive histopathologic features and disparate outcomes among black women with PT. A multi-institutional PT registry would facilitate improved knowledge about race-related differences in the presentation and outcomes of this rare tumor.

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.

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.

Pediatric and Adolescent Breast Conditions: A Review

Breast conditions in pediatric and adolescent patients vary from benign congenital changes to pathological findings. Although most breast conditions are benign, there are rare cases of malignancy that are important to identify during development. As such, it is critical to understand the classification and management of the different pediatric and adolescent breast conditions that might present to clinicians who care for pediatric and adolescent patients. In this review, congenital, benign, and malignant pediatric/adolescent breast conditions are discussed.

An integrative approach for exploring the nature of fibroepithelial neoplasms

BACKGROUND

Malignant phyllodes tumour (MPT) is a rare breast malignancy with epithelial and mesenchymal features. Currently, there are no appropriate research models or effective targeted therapeutic approaches for MPT.

METHODS

We collected fresh frozen tissues from nine patients with MPT and performed whole-exome and RNA sequencing. Additionally, we established patient-derived xenograft (PDX) models from patients with MPT and tested the efficacy of targeting dysregulated pathways in MPT using the PDX model from one MPT.

RESULTS

MPT has unique molecular characteristics when compared to breast cancers of epithelial origin and can be classified into two groups. The PDX model derived from one patient with MPT showed that the mouse epithelial component increased during tumour growth. Moreover, targeted inhibition of platelet-derived growth factor receptor (PDGFR) and phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) by imatinib mesylate and PKI-587 showed in vivo tumour suppression effects.

CONCLUSIONS

This study revealed the molecular profiles of MPT that can lead to molecular classification and potential targeted therapy, and suggested that the MPT PDX model can be a useful tool for studying the pathogenesis of fibroepithelial neoplasms and for preclinical drug screening to find new therapeutic strategies for MPT.

Fibroepithelial lesions of the breast: improving the accuracy of imaging diagnosis and reducing unnecessary biopsy

Fibroadenomas and phyllodes tumours are fibroepithelial lesions of the breast. Fibroadenomas are common benign breast masses encountered both symptomatically and incidentally. Phyllodes tumours are uncommon and usually present symptomatically. Management of fibroadenomas focuses on reducing biopsies without missing cancers while radiological management of phyllodes tumours should focus on predicting the need for surgical excision with or without margins.