Breast, pleomorphic adenoma

The glandular component of the breast includes both myoepithelial and epithelial cells—a feature the breast has in common with the salivary gland. As a result, there is a group of breast tumours that are highly analogous to tumours of the salivary gland. This case is a tumour with benign-appearing myoepithelial and epithelial cells, admixed within a chondroid matrix, and is best classified as a pleomorphic adenoma. In this case, the tumour is distinguished from a metaplastic carcinoma by features that are well differentiated and low-grade, and by circumscribed borders.