Distant metastases in phyllodes tumours of the breast: an overview

Phyllodes tumours (PTs) of the breast are uncommon fibroepithelial neoplasms, comprising 0.3 – 1.0% of all primary breast malignancies in Western countries, but accounting for a higher proportion of primary breast tumours in Asian countries. They are graded as benign, borderline or malignant based on the World Health Organisation (WHO) classification, according to a constellation of 5 histologic parameters. While most PTs carry a good prognosis, malignant and occasionally borderline PTs have the potential to metastasize to distant sites. Although events of distant metastasis are few, the prognosis for such patients is dismal, as they are often unresponsive to chemotherapy with high mortality. This review seeks to provide an overview of this rare but important phenomenon of distant metastases in PTs of the breast.