Pleomorphic adenoma of the human female breast.

We are presenting an interesting rare benign breast tumor which meets the characteristics of a salivary gland pleomorphic adenoma. The tumor was misdiagnosed during frozen section procedure, because several clusters, mainly composed of myoepithelial cells and surrounded by a chondroid matrix, were mistaken for cancerous blasts. Additionally the clinical and mammographic findings were very suspicious. Although this particular tumor is very infrequent, the pathologist should be aware of the difficulties in the differential diagnosis during frozen section and thus defer his final answer to the paraffin sections.