Benign mixed tumor (pleomorphic adenoma) of the breast: Ultrastructural study and review of the literature

A patient is presented with a benign mixed tumor (pleomorphic adenoma) of the breast. There are 11 well-documented cases of this rare breast neoplasm. It is histologically and ultrastructurally identical to that seen in the salivary gland and follows a similar benign course. A central role of the ductal myoepithelial cell is proposed for the histogenesis of this tumor.