REVIEW| Volume 55, ISSUE 4, P437-448, June 2023

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Refining the classification of breast phyllodes tumours

  • Puay Hoon Tan
    Address for correspondence: Dr Puay Hoon Tan, Luma Medical Centre, Royal Square Medical Centre, 101 Irrawaddy Road, #20-02 to 04, Singapore 329565, Singapore.
    Luma Medical Centre, Singapore

    KK Women's and Children's Hospital, Singapore

    Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore

    Department of Pathology, University of Western Sydney, Sydney, NSW, Australia
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      Phyllodes tumours of the breast are uncommon fibroepithelial neoplasms that pose recurrent classification challenges, in large part due to the multiple histological parameters of stromal hypercellularity and atypia, stromal mitotic count, stromal overgrowth and tumour borders, that are used for grading. While the World Health Organization (WHO) Classification of Breast Tumours provides recommendations on diagnostic features, defining criteria are not always applied in routine practice. Lack of concordance among pathologists in typing and grading further underscores the classification difficulties, especially in the borderline category. Although there has been significant molecular information on phyllodes tumours in recent years which has been diagnostically helpful, it has not been translated into daily clinical practice.
      In order to refine the classification of phyllodes tumours into one that is simple yet comprehensive, reproducible and prognostically precise, a multipronged approach is needed that leverages on global contributions of the International Fibroepithelial Consortium, support by the International Collaboration on Cancer Classification and Research (IC3 R) in amalgamating evidence translation, and guidance from the International Collaboration on Cancer Reporting (ICCR) for standardised reporting. It is hoped that the evidence generated can be used towards refining the classification of phyllodes tumours for the future.

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