Metastatic myoepithelioma of the breast.

Myoepitheliomas are typically benign tumours arising from exocrine glands. There have only been five reports of malignant myoepitheliomas from breast origin previously published in the English literature. This report describes a patient with myoepithelioma arising in the breast which later metastasized despite the primary tumour having benign histological features. Impaired immune function due to end-stage renal failure and haemodialysis may have contributed to the malignant potential of her tumour. The literature regarding myoepithelial tumours is reviewed. All breast myoepitheliomas should be managed as potentially malignant tumours with appropriate surgical clearance and staging.