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

Postoperative surgical margin results of the phyllodes tumors from a tertiary hospital

OBJECTIVE

Phyllodes tumors in the breast are exceptionally uncommon fibroepithelial tumors. In the literature, they are typically categorized as benign phyllodes tumor, borderline phyllodes tumor, and malignant phyllodes tumor. This study aims to assess and present the clinical and surgical outcomes of patients diagnosed with phyllodes tumor.

METHODS

The outcomes of patients aged 18 years and above diagnosed with phyllodes tumor between 2006 and 2023 were retrospectively reviewed. Patients were grouped as benign phyllodes tumor and borderline/malignant phyllodes tumor and compared by clinical and surgical results.

RESULTS

Of all 57 patients with phyllodes tumor, 64.9% (n=37) were benign phyllodes tumor and 35.1% (n=20) were borderline/malignant phyllodes tumor [22.8% (n=13) borderline phyllodes tumor and 12.3% (n=7) malignant phyllodes tumor]. When the patients were divided into two groups as benign phyllodes tumor and borderline/malignant phyllodes tumor and compared, our cumulative (total) recurrence rate was 14.0%, with final surgical margin width between groups [(0

CONCLUSION

Phyllodes tumors of the breast can be followed up with a narrow negative surgical margin (0 mm Collapse

Key Words

• breast
• phyllodes tumor
• neoplasm
• recurrence

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MESH Headings

• Humans
• Phyllodes Tumor/surgery
• Phyllodes Tumor/pathology
• Female
• Margins of Excision
• Breast Neoplasms/surgery
• Breast Neoplasms/pathology
• Adult
• Retrospective Studies
• Middle Aged
• Tertiary Care Centers
• Neoplasm Recurrence, Local/pathology
• Young Adult
• Treatment Outcome
• Postoperative Period
• Mastectomy/methods
• Aged
• Adolescent

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Grants Collapse

Affiliation(s)

Fatih Dal University of Health Sciences, Turkish Ministry of Health, İstanbul Training and Research Hospital, Department of General Surgery – İstanbul, Turkey
Semiha Battal Havare University of Health Sciences, Turkish Ministry of Health, İstanbul Training and Research Hospital, Department of Medical Pathology – İstanbul, Turkey

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Histopathological Downgrading of Borderline Phyllodes Tumor in a Young Patient Following Chemotherapy: A Case Report

Phyllodes tumors (PT) are fibroepithelial neoplasms that are treated by complete surgical excision. The effectiveness of adjuvant therapies, including radiotherapy and chemotherapy, for PT remains unclear, and the use of neoadjuvant chemotherapy (NAC) is yet to be established. We report a case of a 15-year-old girl with acute lymphatic leukemia (ALL) who was incidentally diagnosed with a 50-mm borderline PT in the left breast using computed tomography, ultrasonography, and histological examination following needle biopsy. Lumpectomy was performed after administration of anthracycline-based chemotherapy for ALL, resulting in tumor size reduction. Histopathological examination of the excised specimen demonstrated decreased mitotic activity and stromal cellularity post-chemotherapy. To our knowledge, this is the first study to report the histopathological differences in pre- and post-chemotherapy borderline PT samples. Our findings suggest that NAC may induce changes in borderline PT, potentially affecting diagnosis and treatment decisions. Hence, further investigation is warranted in this regard.

Malignant Phyllodes Tumors of the Breast With Rhabdomyosarcomatous Differentiation: A Case Report and Literature Review

Phyllodes tumor (PT) is a rare fibroepithelial breast neoplasm that is typically graded histopathologically as benign, borderline, and malignant. Malignant PTs (MPTs) exhibit marked stromal cellularity, atypia, overgrowth, increased mitotic activity, and the propensity to metastasize. MPTs represent 10%-15% of all PT cases and often have a notably aggressive disease course. Infrequently, these tumors contain heterologous histological elements, including liposarcoma and fibrosarcoma, among others. Rhabdomyosarcomatous differentiation is an exceptionally rare example of such variation. This report documents the clinical presentation and disease course of a 62-year-old woman diagnosed with MPT with rhabdomyosarcomatous differentiation, just the seventh such confirmed case in the English literature. The patient experienced an arduous disease course, developing metastases to her lungs and axial skeleton just months after her initial diagnosis. Palliative radiation and chemotherapy were initiated, but the patient unfortunately succumbed to her disease just 10 months after the initial diagnosis. This case adds to the scarce literature surrounding the rare development of a heterologous rhabdomyosarcomatous element in an MPT, as well as the decision-making process surrounding the use of radiation to treat such lesions. The details discussed in this paper may inform future approaches for patients diagnosed with this disease.

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.

Emergency Resection of a Bleeding Ruptured Malignant Phyllodes Tumor of the Breast

Ruptured phyllodes tumors, though extremely rare, can necessitate emergency surgery in certain cases, particularly those with active bleeding. A 51-year-old woman presented to our hospital with a newly identified mass in her right breast that developed over the past two months. The tumor had ruptured through the paramammary nipple. While initially diagnosed with a phyllodes tumor and scheduled for elective surgery, she experienced active bleeding from the ruptured tumor, leading to a drop in hemoglobin levels. An emergency right simple mastectomy was performed to control the bleeding. Postoperatively, no complications or recurrences were observed. Phyllodes tumors, which are characterized by rapid growth, may present with active bleeding following rupture and may require emergency surgery.