A benign or malignant tumor that arises from the breast and originates from or is composed of myoepithelial cells. Representative examples include adenomyoepithelioma, myoepitheliosis, and malignant myoepithelioma. The disease is Monarch Disease Ontology identifier MONDO_0002483 (breast myoepithelial tumor). Also known as: breast myoepithelial neoplasm.