Phyllodes tumours of the breast: a 20-year institutional series with emphasis on criteria for malignancy.

BACKGROUND: Although histological criteria underpin current classification, accurate risk stratification, particularly for borderline and malignant tumours, remains challenging. METHODS: We analysed a 20-year institutional series of phyllodes tumours (PTs), integrating clinicopathological data with long-term clinical outcomes. Histological features were extracted from original pathology reports, with slide re-review where archival material was available. RESULTS: edition recommendation. The low event rate precluded robust multivariable analysis. CONCLUSION: Our results highlight the biological heterogeneity of malignant PTs and the limitations of rigid histological thresholds. These findings underscore the need for collaborative, multi-institutional prospective studies with standardised tumour sampling and reporting and molecular correlation to refine clinically meaningful risk stratification in PT.