Pleomorphic Adenoma : Mitoses
Classic pleomorphic adenomas usually have very low proliferation rate (Ki-67 index is usually < 5%). Cellular pleomorphic adenomas show increased cellularity and may have bizarre cells with slightly increased mitotic activity. Atypical pleomorphic adenoma show features such as anaplasia, atypical mitosis, and pose a risk for development of carcinoma. This high power image shows a mitotic figure in a cellular pleomorphic adenoma.