Retrospective analysis of core-needle and vacuum-assisted breast biopsies of B3 fibroepithelial lesions and correlation with results in subsequent surgical specimens.

BACKGROUND: Fibroepithelial lesions (FEL) are a heterogeneous group of biphasic tumours that include fibroadenomas (FA) and the rare entity of benign phyllodes tumors (PT) as well as cases where distinction between these two entities is not possible. The histologic distinction between benign PT and cellular FA is still a diagnostic challenge, especially in core-needle biopsy (CNB) or vacuum-assisted biopsy (VAB). Guidelines are not clearly established regarding the management of FEL in CNB or VAB. In this study, we addressed the frequency of B3 FEL diagnosed in CNB or VAB and compared the final histopathological findings in the excision specimens to evaluate up- or downgrading. METHODS: We identified 117 female patients with the preoperative diagnosis of FEL (B3), PT, or FEL in combination of pure epithelial B3 lesions in CNB or VAB. Clinico-pathological information as well as data on subsequent surgical excision were available for all patients. RESULTS: PT was diagnosed in 9 (14.8%) and FEL (B3) in 52 (85.2%) cases. Additionally, 56 patients with FA in combination with an additional B3 lesion were identified. Most FEL (B3)/PT initial diagnoses were made in CNB (55.6% of PT; 84.6% of FEL). After the initial biopsy, 7 of 9 (77.8%) patients with initial diagnosis of benign or borderline PT in CNB/VAB and 40 of 52 (77.0%) patients with initial diagnosis of FEL (B3) in CNB/VAB underwent open excision (OE). 4 of 9 cases (44.4%) initially diagnosed as PT were verified, whereas 2 of 9 (22.2%) were downgraded to FA. 20 of 52 cases (38.5%) initially diagnosed as FEL (B3) were downgraded to FA, whereas 11 of 52 cases (21.2%) were diagnosed as benign or borderline PT. One FEL (B3) case was upgraded to malignant PT. CONCLUSION: Most PT and FEL (B3) diagnoses on CNB/VAB underwent surgical removal. In the final pathological findings of cases classified primarily as FEL (B3), the majority were downgraded to FA, one quarter were upgraded to PT, and a small subset remained as combined FA/PT. In clinical daily practice, we recommend individualized decision-making considering different options (clinical follow-up or removal of the lesion depending on the whole context) in a multidisciplinary preoperative conference.

Comparison of the Ultrasonography Features of the Breast in Women with Fibroadenoma and Those with Other Breast Lumps.

BACKGROUND: Fibroadenoma (FA) is documented as the most common benign breast disease typically presenting as a lump. A wide variety of other diseases including breast cancer can similarly present as lumps hence the need for further differentiation. Ultrasonography plays a vital role in the evaluation and treatment of breast lumps with histological analysis as the gold standard. OBJECTIVE: This study compared the physical and sonographic features of the breast in women with FA and women with breast lumps due to other diseases. MATERIALS AND METHODS: This is a single-centre comparative study. Clinical and sonographic breast evaluations of the recruited patients with lumps were done and reported using the American College of Radiology Breast Imaging Reporting and Data System score. The lumps were biopsied, and histological diagnosis was documented. Clinical and imaging features of the breasts of women with FA were then compared with those of women with lumps from other breast diseases, and collated data were analysed using SPSS Statistical version 23.0. RESULTS: Data from 118 subjects (59 in each group) were used for this study. There was a significant difference in the physical and sonographic appearance of FA concerning the patient's age, parity, change in lesion size, perilesional architecture, echogenicity, borders, capsule and background breast density. No FA was found in women with less dense breasts. CONCLUSION: The sonographic features of breasts showed some differences from the corresponding features of FA and other breast lesions. This has the potential to increase the efficiency of pre-operative diagnosis of FA and could be further applied in developing diagnostic criteria for FA in our environment.

Five-year follow-up after a single US-guided high intensity focused ultrasound treatment of breast fibroadenoma.

The aim of this study was to evaluate the long-term efficacy of a single ultrasound-guided high-intensity focused ultrasound (US-HIFU) treatment in patients with breast fibroadenoma (FA) in terms of volume and pain reduction as well as palpation findings. From december 2013 until november 2014 27 women with a symptomatic FA were treated in one HIFU-session. Follow-up visits were performed after 7 days, 6 months and 1, 2, 3 and 5 years with clinical examination and ultrasound. One year after the procedure, a core needle biopsy of the residual lesion was offered. There was a significant volume reduction 6 months after HIFU from 1083.10 to 347.13 mm3 (p < 0.0001) with a mean volume reduction ratio (VRR) of 61.63%. Thereafter the FAs showed a further, but no longer significant decrease in size. One patient with an initial incomplete ablation and histologically confirmed persistent vital cells after 1 year showed a strong regrowth after 3 years. Excluding this patient from analysis, the mean VRR at months 12, 24, 36, and 60 was 86.44%, 94.44%, 94.90%, and 97.85%, respectively. Before HIFU, 59.26% of the patients had pain (22.33/100 VAS) which decreased to 6.56/100 after 12 months and remained reduced over the 5 year follow up period. A decrease in palpability from 85.19 to 7.69% was observed within 24 months. A single HIFU intervention let to a substantial reduction in size, pain, and palpability with its most potential effect during the first 12 months. Subsequently, the observed effect remained stable over a 5 year follow up period. Incomplete initial treatment was associated with the risk of regrowth.

G2/M Checkpoint Modulation: Insights from miRNA Profiles in FAM and Breast Cancer.

OBJECTIVE: The aim of this research is to understand the role of microRNA in cell cycle regulation especially on G2M Checkpoint from Luminal A samples Indonesian population. The profile results are used as biomarkers and therapeutic targets for breast cancer. For this reason, analysis was carried out on the comparison of miRNA expression between Luminal A and Fibroadenoma  mamae (FAM) using Nanostring nCounter. METHODS: In this study, 5 (Formalin-Fixed Paraffin-Embedded) FFPE Luminal A tissues and 4 FFPE FAM samples were used. RNA was isolated from cancer tissue samples. Differential expression analysis of miRNA was conducted using Nanostring nCounter technology, subsequently followed by the expression analysis between FAM and Luminal A using nSolver softwere. Elevated expression levels of miRNAs were subjected to pathway and gene regulation analysis using KEGG and GSEA MsigDB databases. Data visualization was performed utilizing Cytoscape, NetworkAnalyst, and SRplot tools. RESULT: Based on 792 miRNAs detected on Nanostring nCounter, it was found that 60 miRNAs were upregulated and 6 miRNAs were downregulated. The 15 upregulated miRNAs analyzed show their role in the G2M Checkpoint through several pathways. The five miRNAs that significantly regulate the G2M Checkpoint are hsa-miR-196b-5p, hsa-miR-218-5p, hsa-miR-7-5p, hsa-miR-19a-5p, and hsa-miR-18a-5p Where each of these miRNAs regulates the CDKN1B gene. CONCLUSION: Significant differences in the expression of multiple miRNAs between Luminal A and FAM samples were observed. Furthermore, several of these miRNAs were found to modulate the G2M Checkpoint in Luminal A cancer by suppressing tumor suppressor genes.

Clinical efficacy and safety of ultrasound-guided high-intensity focused ultrasound for breast fibroadenoma: a systematic review and meta-analysis.

OBJECTIVE: The purpose of this systematic review and meta-analysis was to assess the clinical efficacy and safety of ultrasound (US)-guided high intensity focused ultrasound (HIFU) in the treatment of breast fibroadenoma in different studies. METHODS: Studies evaluating the efficacy and safety of US-guided HIFU in the treatment of histologically-proven FA with follow-up outcomes of more than 3 months were searched through MEDLINE/PubMed databases. Volume reduction rate (VRR) and side effects were extracted and compared for further analysis. RESULTS: Of 29 identified articles, 10 studies involving 385 women and more than 545 FAs met the inclusion criteria. The mean VRR at 6 months and 12 months after HIFU was 52.00% and 72.00%. In terms of intraoperative safety, nine studies reported mild to moderate pain, with an average visual analogue scale (VAS) score ranging from 1.60 to 7.10. The most common postoperative side effect associated with HIFU was subcutaneous ecchymosis and less frequent were pain, erythema, and skin pigmentation, most of which disappeared within weeks. No serious side effects were observed. CONCLUSION: S-guided HIFU is an effective and safe noninvasive treatment for breast FA that does not cause serious side effects. Further studies are needed to explore crucial influencing factors of VRR.

Potential of non-contrast spiral breast CT to exploit lesion density and favor breast cancer detection: A pilot study.

PURPOSE: To assess the density values of breast lesions and breast tissue using non-contrast spiral breast CT (nc-SBCT) imaging. METHOD: In this prospective study women undergoing nc-SBCT between April-October 2023 for any purpose were included in case of: histologically proven malignant lesion (ML); fibroadenoma (FA) with histologic confirmation or stability > 24 months (retrospectively); cysts with ultrasound correlation; and women with extremely dense breast (EDB) and no sonographic findings. Three regions of interest were placed on each lesion and 3 different area of EDB. The evaluation was performed by two readers (R1 and R2). Kruskal-Wallis test, intraclass correlation (ICC) and ROC analysis were used. RESULTS: 40 women with 12 ML, 10 FA, 15 cysts and 9 with EDB were included. Median density values and interquartile ranges for R1 and R2 were: 60.2 (53.3-67.3) and 62.5 (55.67-76.3) HU for ML; 46.3 (41.9-59.5) and 44.5 (40.5-59.8) HU for FA; 35.3 (24.3-46.0) and 39.7 (26.7-52.0) HU for cysts; and 28.7 (24.2-33.0) and 33.3 (31.7-36.8) HU for EDB. For both readers, densities were significantly different for ML versus EDB (p < 0.001) and cysts (p < 0.001) and for FA versus EDB (p=/<0.003). The AUC was 0.925 (95 %CI 0.858-0.993) for R1 and 0.942 (0.884-1.00) for R2 when comparing ML versus others and 0.792 (0.596-0.987) and 0.833 (0.659-1) when comparing ML versus FA. The ICC showed an almost perfect inter-reader (0.978) and intra-reader agreement (>0.879 for both readers). CONCLUSIONS: In nc-SBCT malignant lesions have higher density values compared to normal tissue and measurements of density values are reproducible between different readers.

The potential mechanism of HIF-1α and CD147 in the development of triple-negative breast cancer.

BACKGROUND: Triple-negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis, and the outcomes of common therapy were not favorable. METHODS: The samples of 84 patients with TNBC and 40 patients with breast fibroadenoma were collected in the pathology department specimen library of our hospital. The prognosis of patients was obtained through outpatient follow-up information, telephone and WeChat contacts, and medical records. The mRNA expression was analyzed using bioinformation and quantitative real-time polymerase chain reaction (qPCR). The protein expression was determined by hematoxylin-eosin staining and immunohistochemical staining. The results of survival analysis were visualized using Kaplan-Meier curves. RESULTS: The immunohistochemical staining showed that hypoxia-inducible factor-1alpha (HIF-1α) was mainly distributed in the nucleus and cytoplasm, while CD147 is mainly distributed in cell membrane and cytoplasm. The qPCR results exhibited that the expression level of HIF-1α and CD147 in TNBC tissue was significantly higher than that in breast fibroadenoma tissue. The expression of HIF-1α was related to the histological grade and lymph node metastasis in TNBC, and the expression of CD147 was related to Ki-67, histological grade and lymph node metastasis. There was a positive relationship between the expression of CD147 and HIF-1α. The upregulated expression of CD147 was closely related to the poor prognosis of OS in TNBC. CONCLUSION: CD147 could be a biomarker for the prognosis of TNBC and closely related to the expression of HIF-1α.

Ultrasound-guided cryoablation: Our experience in percutaneous treatment as an alternative to surgery for fibroadenomas of the breast lesions.

OBJECTIVES: To review the tolerance to and medium-term efficacy of ultrasound-guided cryoablation as an alternative to surgical treatment of fibroadenomas of the breast in our hospital. METHODS: We analyzed data from the 12 patients with fibroadenomas treated with ultrasound-guided cryoablation in our hospital between November 2020 and July 2022. Cryoablation was performed with a system using argon gas (Galil Boston Scientific®) or liquid nitrogen (Prosense Ice Cure®) following a triple-phase (freeze-thaw-freeze) protocol of variable duration depending on the size of the lesion. Patients were followed up with ultrasonography at 3, 6, 12, and 18 months. RESULTS: All patients tolerated the procedure well. Two patients reported moderate pain in the hours immediately after the procedure; no other complications occurred. The findings during follow-up included decreased volume of the fibroadenoma (47.07% at 3 months, 77.79% at 6 months, 81.77% at 12 months, and 88.81% at 18 months), blurring of the nodule's margins, a significantly reduced or absent signal within the lesion in the Doppler study, an echogenic band (representing edema, hemorrhage, and fat necrosis), and hypoechoic areas suggestive of fibrosis surrounding the fibroadenoma. CONCLUSIONS: Cryoablation is done on an outpatient basis, avoiding general anesthesia, thus making it less expensive. Cryoablation yields better cosmetic results than surgery.

Endoscopic excision of breast fibroadenoma through inframammary fold: Feasibility, safety and medium-term outcomes.

INTRODUCTION: Endoscopic-assisted surgery for breast tumors has the advantage of inconspicuous scars, less breast volume loss, and nipple areolar distortion. A novel endoscopic-assisted technique through inframammary fold for excision of fibroadenomas is presented. MATERIALS AND SURGICAL TECHNIQUE: Endoscopic-assisted excision of fibroadenoma(s) through inframammary fold was performed in four patients after informed written consent via three ports (12, 5, and 5 mm). Breast Cancer Treatment Outcome Score-12 (BCTOS-12) was used to evaluate patient satisfaction after surgery. DISCUSSION: No intraoperative and wound complication was noted. On median follow-up of 26.5 months, patients reported satisfactory responses to aesthetic and functional outcomes. No scar related complications were noted. Endoscopic-assisted excision of fibroadenoma through inframammary fold can be a safe and feasible option with good aesthetic outcomes.

An Effective Ultrasound Features-Based Diagnostic Model via Principal Component Analysis Facilitated Differentiating Subtypes of Mucinous Breast Cancer From Fibroadenomas.

BACKGROUND: Mucinous breast carcinoma (MBC) is often misdiagnosed as fibroadenoma (FA),which can lead to inappropriate or delayed treatments. This study aimed to establish an efficient ultrasound (US)-based diagnostic model to distinguish MBC subtypes from FAs. METHODS: Between January 2017 and February 2024, 240 lesions were enrolled, comprising 65 cases of pure mucinous breast carcinoma (PMBC), 47 cases of mixed mucinous breast carcinoma (MMBC), and 128 cases of FAs. Ten US feature variables underwent principal component analysis (PCA). Models were constructed based on components explaining over 75% of the total variation, with varimax rotation applied for interpretability. Comprehensive models were developed to distinguish PMBCs and MMBCs from FAs. RESULTS: Six principal components were selected, achieving a cumulative contribution rate of 77.46% for PMBCs vs. FAs and 78.62% for MMBCs vs. FAs. The principal component of cystic-solid composition and posterior acoustic enhancement demonstrated the highest diagnostic value for distinguishing PMBCs from FAs (AUC: 0.86, ACC: 80.31%). Features including vascularization, irregular shape, ill-defined border, and larger size exhibited the highest diagnostic value for distinguishing MMBCs from FAs (AUC: 0.90, ACC: 87.43%). The comprehensive models showed excellent clinical value in distinguishing PMBCs (AUC = 0.86, SEN = 86.15%, SPE = 73.44%, ACC = 77.72%) and MMBCs (AUC = 0.92, SEN = 80.85%, SPE = 95.31%, ACC = 91.43%) from FAs. CONCLUSION: This diagnostic model holds promise for effectively distinguishing PMBCs and MMBCs from FAs, assisting radiologists in mitigating diagnostic biases and enhancing diagnostic efficiency.

A prediction model based on digital breast pathology image information.

BACKGROUND: The workload of breast cancer pathological diagnosis is very heavy. The purpose of this study is to establish a nomogram model based on pathological images to predict the benign and malignant nature of breast diseases and to validate its predictive performance. METHODS: In retrospect, a total of 2,723 H&E-stained pathological images were collected from 1,474 patients at Qingdao Central Hospital between 2019 and 2022. The dataset consisted of 509 benign tumor images (adenosis and fibroadenoma) and 2,214 malignant tumor images (infiltrating ductal carcinoma). The images were divided into a training set (1,907) and a validation set (816). Python3.7 was used to extract the values of the R channel, G channel, B channel, and one-dimensional information entropy from all images. Multivariable logistic regression was used to select variables and establish the breast tissue pathological image prediction model. RESULTS: The R channel value, B channel value, and one-dimensional information entropy of the images were identified as independent predictive factors for the classification of benign and malignant pathological images (P < 0.05). The area under the curve (AUC) of the nomogram model in the training set was 0.889 (95% CI: 0.869, 0.909), and the AUC in the validation set was 0.838 (95% CI: 0.7980.877). The calibration curve results showed that the calibration curve of this nomogram model was close to the ideal curve. The decision curve results indicated that the predictive model curve had a high value for auxiliary diagnosis. CONCLUSION: The nomogram model for the prediction of benign and malignant breast diseases based on pathological images demonstrates good predictive performance. This model can assist in the diagnosis of breast tissue pathological images.

Fibroadenoma of the vulva with pseudoangiomatous stromal hyperplasia: A common neoplasm in uncommon site.

Mammary-type tissue in the vulva was first described in 1872 but has been rarely reported in the literature. This tissue was previously considered as ectopic breast tissue that occurs as a result of incomplete regression of the milk line. Similar to native breast tissue, ectopic mammary tissue is hormone-sensitive and can develop benign changes, such as fibroadenoma, as well as malignant changes. A more recent theory suggests that these benign and malignant mammary-type entities arise from mammary-like anogenital glands, which constitute normal vulvar components. We report a case of a 41-year-old woman who presented with a chronic asymptomatic cyst on the left vulva that eventually became uncomfortable, especially on standing. The cyst was located on the labium minus, measuring 1.0 × 0.5 cm, with no identified erythema or other skin abnormalities. Excision of the lesion and subsequent microscopic examination showed a circumscribed mass with a nodular overgrowth of epithelial and stromal components, resembling a mammary fibroadenoma with pseudoangiomatous stromal hyperplasia. We bring to attention this rare diagnosis and the importance of considering it in the presence of a vulvar lesion. The malignant and recurrence potential of mammary-type tissue necessitates excision with clear margins and close monitoring of these patients.

Breast cysticercosis - a case report.

SUMMARY: Isolated incidences of human cysticercosis have been reported world-wide, but it remains a major public health concern in endemic areas such as Mexico, Africa, South-East Asia, Eastern Europe, and South America. Cysticercosis most commonly involves the skeletal muscle, subcutaneous tissue, brain, and eyes. The breast is an uncommon site of presentation for cysticercosis. Due to its rare occurrence, breast cysticercosis is often initially mistaken for other common breast lesions such as cysts, abscess, malignant tumours and fibroadenomas. We report a case of breast cysticercosis in a young South African woman.

Atypia Involving Fibroadenomas: Outcomes and Upgrade Rates.

OBJECTIVE: Fibroadenomas (FAs) involved by atypia are rare. Consensus guidelines for management of FAs involved by atypia when diagnosed on image-guided biopsy do not exist because of limited data reporting surgical upgrade rates to ductal carcinoma in situ (DCIS) or invasive malignancy. Therefore, these lesions commonly undergo surgical excision. METHODS: This single-institution retrospective study identified cases of FAs involved by atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), and/or lobular carcinoma in situ (LCIS) diagnosed on image-guided biopsy between January 2014 and April 2023 to determine upgrade rates. Cases with incidental atypia adjacent to but not involving FAs were excluded. RESULTS: Among 1736 FAs diagnosed on image-guided biopsy, 32 cases (1.8%) were FAs involved by atypia including 43.8% (14/32) ALH, 28.1% (9/32) ADH, 18.8% (6/32) LCIS, 6.3% (2/32) LCIS + ALH, and 3.1% (1/32) unspecified atypia. The most common imaging finding was a mass. Most cases, 81.3% (26/32), underwent subsequent surgical excisional biopsy. A single case of ADH involving and adjacent to an FA was upgraded to FA involved by low-grade DCIS on excision for an overall surgical upgrade rate of 3.8%. There were no cases upgraded to invasive malignancy. For those omitting surgical excision, there was no subsequent malignancy diagnosis at the FA biopsy site over a mean follow-up of 73 months. CONCLUSION: Cases of radiologic-pathologic concordant FAs involved by atypia have a low upgrade rate of 3.8% and should undergo multidisciplinary review. Larger multi-institutional analysis is needed to determine whether guidelines for excision of atypia should apply to atypia involving FAs.

Using the DNA Integrity Number to Analyze DNA Quality in Specimens Collected from Liquid-Based Cytology after Fine-Needle Aspiration of Breast Tumors and Lesions.

INTRODUCTION: Cancer genome analysis using next-generation sequencing requires adequate and high-quality DNA samples. Genomic analyses were conventionally performed using formalin-fixed paraffin-embedded sections rather than cytology samples such as cell block or smear specimens. Specimens collected from liquid-based cytology (LBC) have the potential to be sources of high-quality DNA suitable for genetic analysis even after long-term storage. METHODS: We collected breast tumor/lesion fractions from 92 residual LBC specimens using fine-needle aspiration (FNA) biopsy, including breast carcinoma (1 invasive carcinoma and 4 ductal carcinomas in situ), papillomatous lesion (5 intraductal papillomas), and fibroepithelial lesion (19 phyllodes tumors and 53 fibroadenomas) samples, and others (1 ductal adenoma, 1 hamartoma, 1 fibrocystic disease, and 7 unknown). DNA was extracted from all samples and subjected to DNA integrity number (DIN) score analysis. RESULTS: Average DIN score collected from 92 LBC specimens was significantly higher score. In addition, high-quality DNA with high DIN values (7.39 ± 0.80) was successfully extracted more than 12 months after storage of residual LBC specimens. CONCLUSION: Residual LBC specimens collected from FNA of the breast were verified to carry high-quality DNA and could serve as an alternate source for genetic analysis.

Double blind randomized controlled trial of efficacy of ormeloxifene for the treatment of fibroadenoma (The FIBROCENT study).

BACKGROUND: We evaluated the effectiveness of Ormeloxifene (Centchroman) on regression of Fibroadenoma in a double-blind randomized controlled trial. METHODS: Patients with biopsy proven Fibroadenoma were enrolled between March 2023 and October 2023 and divided in two arms- Ormeloxifene group and Placebo group. Effectiveness of the treatment was evaluated using USG. No residual mass was defined as complete regression and more than 30% decrease in size was considered as partial regression. RESULTS: A total of 130 consecutive patients with Fibroadenoma were randomized to Ormeloxifene group (n = 65) and Placebo Group (n = 65). Complete regression was observed in 9% (6/65) patients in Ormeloxifene group and 10.8% (7/65) in Placebo Group at the end of 12 weeks (p = 0.49). Twenty one patients taking Ormeloxifene reported adverse events as compared to none in the other group. CONCLUSION: In our study Ormeloxifene was not found to be effective in treatment of fibroadenoma and had concerning side effects.

Surgical management of a giant fibroadenoma during lactation.

Fibroadenomas are the most common breast lesion in women of reproductive age. During pregnancy and lactation, fibroadenomas can undergo rapid growth in response to hormonal stimulus. These changes may prompt further investigation and/or intervention due to the risk of an underlying phyllodes tumour. We present a case of a female patient who underwent surgical excision of a giant fibroepithelial lesion at 4 months post partum while continuing to breastfeed. The lesion was successfully excised while maintaining lactation. A postoperative milk fistula resolved with non-operative management. There is limited literature on the surgical management of breast lesions in lactating women. This case illuminates the surgical management of breast lesions in an often well informed group of patients who may choose to have surgery while lactating in spite of the increased risk of complications. This case also highlights the need for a holistic approach to maintain the overall health of mother and child.

Differential diagnosis of breast mucinous carcinoma with an oval shape from fibroadenoma based on ultrasonographic features.

BACKGROUND: Approximately 50% of breast mucinous carcinomas (MCs) are oval and have the possibility of being misdiagnosed as fibroadenomas (FAs). We aimed to identify the key features that can help differentiate breast MC with an oval shape from FA on ultrasonography (US). METHODS: Seventy-six MCs from 71 consecutive patients and 50 FAs with an oval shape from 50 consecutive patients were included in our study. All lesions pathologically diagnosed. According to the Breast Imaging Reporting and Data System (BI-RADS), first, the ultrasonographic features of the MCs and FAs were recorded and a final category was assessed. Then, the differences in ultrasonographic characteristics between category 4 A (low-risk group) and category 4B-5 (medium-high- risk group) MCs were identified. Finally, other ultrasonographic features of MC and FA both with an oval shape were compared to determine the key factors for differential diagnosis. The Mann-Whitney test, χ2 test or Fisher's exact test was used to compare data between groups. RESULTS: MCs with an oval shape (81.2%) and a circumscribed margin (25%) on US were more commonly assessed in the low-risk group (BI-RADS 4 A) than in the medium-high-risk group (BI-RADS 4B-5) (20%, p < 0.001 and 0%, p = 0.001, respectively). Compared with those with FA, patients with MC were older, and tended to have masses with non-hypoechoic patterns, not circumscribed margins, and a posterior echo enhancement on US (p < 0.001, p < 0.001, and p = 0.003, respectively). CONCLUSION: The oval shape was the main reason for the underestimation of MCs. On US, an oval mass found in the breast of women of older age with non-hypoechoic patterns, not circumscribed margins, and a posterior echo enhancement was associated with an increased risk of being an MC, and should be subjected to active biopsy.

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.