Introduction Fibroepithelial lesions of the breast mainly include fibroadenoma and phyllodes tumors with overlapping morphological features and varied clinical behavior. This study aims to determine the histopathological spectrum of fibroepithelial lesions of the breast in a tertiary care hospital. Methods This is a cross-sectional study that was carried out in the pathology department from 1st January 2015 to 31st December 2023. Relevant data of all fibroepithelial lesions reported during the study period were retrieved from the medical records, tabulated, and analyzed. The Pearson chi-square test was used to determine the significant association between the various clinicopathological parameters of fibroepithelial lesions. A p-value of less than 0.05 was taken as statistically significant. Results Out of a total of 195 fibroepithelial lesions, 185 (95%) were fibroadenoma, 07 (3.5%) were phyllodes tumors, and three (1.5%) were fibroadenoma with tubular adenoma. The most common age group was 21 to 40 years, with the majority of phyllodes tumors being more than 5 cm in size compared to fibroadenomas. The association between the clinicopathological characteristics such as age of patients, tumor size, and histological grade was statistically insignificant in this study. Conclusions The implementation and usage of morphological diagnostic criteria will help in diagnosing and categorizing this broad group of fibroepithelial lesions, thereby facilitating appropriate treatment for patients.

Phyllodes tumuor (PT) is a rare biphasic breast neoplasm. It constitutes <1% of the entire tumours of the breast. Based on the World Health Organization\'s (WHO) proposal, premised on multiple histological features, phyllodes tumour is categorized into benign, borderline, and malignant breast neoplasms. Malignant phyllodes tumor (MPT) is even a rarer neoplasm. It occurs more commonly in older patients. However, it can uncommonly occur in younger individuals. The transformation of benign phyllodes into malignant forms is extremely rare. Here, we present two cases of young females (aged 20 and 27 years, respectively) who individually presented with rapidly progressive breast lumps. The two breast lumps were huge while one was recurrent and underwent a malignant transformation in approximately 7 weeks interval following an initial complete excision and histological diagnosis of benign PT. Indeed, even in young females below the modal/peak age of phyllodes, the suspicion should be high. Additionally, breast ultrasonography findings, although not common, can be highly suggestive of PT. Furthermore, every breast lump should be further evaluated, and even more so, histologically, irrespective of the patient\'s age as our first patient had an excision without histology.

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.

BACKGROUND: Phyllodes tumor (PT) is an fibroepithelial tumor with potential for local recurrence. The optimal margin for surgical resection of PT is still debated, particularly in cases of positive margins. This study aimed to identify the risk factors for phyllodes tumor recurrence and the effect of a free margin on tumor recurrence by considering these risk factors.
METHODS: This is a retrospective observational study of patients diagnosed with PT who had undergone surgical management. The data were collected from medical records from 2001 to 2020 in the breast clinic of Shahid Motahhari Clinic of Shiraz. Patients were followed up for at least 3 years after the operation to be checked for local recurrence or distant metastasis at regular intervals.
RESULTS: This retrospective study included 319 patients with PT who underwent surgical management. Of these patients, 83.9% (n = 267), 7.6% (n = 24), and 8.5% (n = 27) were classified as benign, borderline, and malignant, respectively. 8.8% of all patients and 7.6% of non-malignant cases experienced local recurrence, and risk factors for recurrence included oral contraceptive use, smoking, size > 4 cm, stromal overgrowth, and stromal cell atypia. A negative surgical margin decreased the prevalence of recurrence in tumors > 4 cm and with stromal overgrowth significantly.
CONCLUSIONS: The study found that a negative margin in all patients did not reduce the recurrence rate in benign and borderline phyllodes tumors, suggesting close follow up as a reasonable alternative. However, a negative margin may be effective in reducing recurrence in certain high-risk groups.

Introduction Phyllodes tumor (PT) is an uncommon fibroepithelial neoplasm of the breast. It is a biphasic tumor with stromal and epithelial components, with a tendency to recur. Because of its wide range of disease manifestations, it has been subclassified into three categories, i.e., benign, borderline, and malignant, based on several histological parameters. This study was conducted to evaluate the clinicopathological features associated with malignancy in breast PTs. Methods We conducted a retrospective study at the Department of Histopathology at Liaquat National Hospital, Karachi, Pakistan. A total of 146 biopsy-proven cases of PTs were enrolled in the study. Clinical data were obtained from the clinical referral forms. Specimens were obtained from either lumpectomy or simple mastectomy. The specimens obtained were received at the laboratory where after gross examination, paraffin-embedded tissue blocks were prepared, which were sectioned, stained, and studied by a senior histopathologist. Pathological features, such as mitotic count, necrosis, stromal atypia, stromal overgrowth, and heterologous elements, were observed. Based on these features, the PTs were classified into benign, borderline, and malignant tumors. Results The mean age of the PTs in our setup was 40.65 ± 12.17 years with a mean size of 9.40 ± 6.49 cm. Malignant PT was found to be the most prevalent in our population, accounting for 63 (43.2%) cases, followed by borderline (51, 34.9%) and benign (32, 21.9%). A significant association was found between the tumor subtype and patient age, i.e., patients diagnosed with malignant and borderline PTs were found to be of older age (mean 42.82 ± 12.94 and 42.05 ± 11.31 years, respectively) than those diagnosed with benign PTs (mean age 34.12 ± 9.75 years). Moreover, malignant PTs were associated with larger tumor size (mean 11.46 ± 6.08) compared with the other two subtypes. Conclusion We found a significant association among patient age, tumor size, and PT subtype. Therefore, apart from the usual histological parameters, patient age and tumor size are important parameters for predicting the behavior of breast PT and should be considered for management.

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.

UNASSIGNED: The presence of eosinophilic inclusion bodies in the breast is very rare and fewer than 20 cases were described in the literature. Herein we report the first case of borderline phyllodes tumour associated with this kind of cells. To the best of our knowledge, this is also the first time that a molecular sequencing is made targeting the stroma cells with inclusion bodies.
METHODS: A 33-yr-old woman presented a large mass in the right breast. Imaging techniques by mammogram and ultrasonographic examination were performed. After multidisciplinary approach, a breast conserving surgery has been decided. Microscopic analysis, immunohistochemical stains and molecular tests were performed on the lesion. The proposed diagnosis is borderline phyllodes tumour with eosinophilic inclusion bodies.
UNASSIGNED: Inclusion bodies are typically found in the infantile digital fibromatosis. Finding them in extradigital fibromatosis is rare. Their signification is still unclear. Some studies suggest a disturbance in the metabolism of proliferating myofibroblasts.
CONCLUSIONS: The presence of inclusion bodies in breast tumour do not seem to have a prognosis impact. It might be interesting to perform others molecular tests on lesions with eosinophilic inclusion bodies to discover potential mutations.

Optimal and tailored surgical treatment of phyllodes tumour(PT) of the breast is controversial. This study aims to determine the appropriate surgical margin in the treatment of PT.
The data of 132 patients who underwent breast surgery with the diagnosis of PT at the Breast Unit of Istanbul Faculty of Medicine from 2000 to 2022 were retrospectively reviewed.
Median age was 38 and patients with benign PT were younger than others(median age was 34, 44, and 43 for benign, borderline, and malignant, respectively) (P = 0.001). Local recurrence was observed in 7 (5.3%) patients, systemic recurrence was observed in 3 (2.3%) patients, and disease-related death was observed in 2 (1.5%) patients. Local recurrence occurred in 1.4% (n = 1) of benign tumours, 8.3% (n = 2) of borderline tumours, and 10.3% (n = 4) of malignant tumours. All of the systemic recurrences and deaths were seen in the malignant group. The local recurrence rate was found to be higher in borderline and malignant tumours with surgical margins less than 10 mm (44.4% versus 3.7%, P = 0.003), and tumours larger than 5 cm (11.8% versus 1.3%, P = 0.015). In comparison, there was no correlation between the surgical margin proximity, tumour diameter, and local recurrence rates in benign PT (P > 0.05).
According to our findings, negative surgical margins seem to be sufficient in the treatment of benign phyllodes tumours. Furthermore at least 1 cm negative surgical margins must be achieved for malignant and borderline phyllodes tumours to avoid local recurrence.

OBJECTIVE: 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.
CONCLUSIONS: 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.

A phyllodes tumour of the vulva is a rare, well-illustrated benign neoplasm having characteristic histo-morphological features similar to a phyllodes tumour of the breast. We report a case of a primary benign phyllodes tumour in a 28-year-old female patient. She was seen in an outpatient clinic presenting with a slow-growing, non-painful lesion on her vulva. Examination revealed a 2 cm cyst located on the labia minora. Complete excision of the cyst was achieved, and pathological examination revealed a benign phyllodes tumour of the vulva. Hallmarks of this rare pathology are classically a leaf-like architectural configuration and fronds projecting into the cystic spaces on a low-power magnification. To date, a grading or classification of these vulva tumours has not been established due to their rarity. There have been very few reported cases of phyllodes tumours occurring on the vulva and fewer still affecting the labia minora. Continued surveillance for recurrence should be adopted.