Breast lesions which mimic others morphologically often present diagnostic challenges for pathologists in their daily practice. Diagnostic errors may be false positive, for example when benign lesions masquerade as in situ or invasive carcinomas or conversely false negative, when malignant lesions are mistaken for in situ or benign entities. This course will include both common as well as less frequently seen morphologic mimics which pathologists and pathologists in training would encounter in their breast pathology practice, and will provide diagnostic strategies useful in recognizing and distinguishing these potentially hazardous cases. Areas to be covered are those often fraught with mimics and include: invasive and pseudoinvasive lesions, in situ carcinomas, papillary lesions, spindle cell and fibroepithelial lesions, lymph node issues, nipple lesions as well as metastases to and from the breast.

A case-based teaching approach will be utilized and will be extensively illustrated with examples drawn from the presenters' routine daily sign-out and consultation practices. Cases to be discussed will be available to registrants prior to the course as web-based digital images, accompanied by pertinent clinical histories. Presentations will strongly emphasize morphologic features throughout but will also integrate ancillary techniques such as immunohistochemistry, highlighting their strengths and limitations. Diagnostic "pearls" which the presenters find useful in their own daily practice will be liberally shared with participants. A comprehensive syllabus will be distributed at the time of the course, and a CD of all cases and PowerPoint slides will be mailed to registrants thereafter.

Upon completion of the course, participants will be more familiar with both common and rarer mimics and will be equipped with diagnostic approaches to effectively recognize and distinguish such entities in their daily practice of breast pathology.

This course may be used for CME credits or SAM's credits.