Pleomorphic adenoma of the breast: report of a case.

We present herein the case of a 74-year-old woman found to have a pleomorphic adenoma, or so-called mixed tumor, of the breast. The patient presented with a hard mass, 3 cm in diameter, located just beneath the left areola. Physical examination suggested a diagnosis of breast carcinoma; however, the findings of both ultrasonography and mammography indicated a benign neoplasm. Aspiration biopsy cytology was evaluated as class III and the diagnosis of pleomorphic adenoma was finally confirmed by examination of an excisional biopsy specimen. As it is a rare benign tumor, pleomorphic adenoma of the breast has been mistaken for a malignant tumor clinically, mammographically, cytologically, and even by frozen section. Thus, an awareness of this disease in the breast will help to prevent misdiagnosis and overaggressive surgery.