The purpose of this course is to present and discuss a number of breast lesions that have recently been recognized (such as flat epithelial atypia; variants of lobular carcinoma in situ; basal-like invasive breast cancers; consequences and artifacts related to prior core needle biopsy) and to provide a re-assessment of several lesions and issues that are well-known to pathologists but for which new/emerging information is available (such as so-called "intracystic" papillary carcinomas; spindle cell carcinomas; angiosarcomas and atypical vascular lesions; issues related to ER testing). Diagnostic and differential diagnostic points will be emphasized as will the clinical significance of these diagnoses and their implications for patient management. The uses and limitations of ancillary techniques such as immunohistochemistry in the evaluation of these lesions will be discussed, where appropriate. A case-oriented/slide seminar-type approach will provide a springboard for discussion of these lesions, all of which are encountered by practicing pathologists and pathologists in training and, based on our experience, repeatedly raise diagnostic and/or management concerns. Case histories and images will be available on the USCAP website for review by registrants prior to the course. A syllabus will be distributed to registrants at the meeting. After the meeting, all participants will receive web access to PowerPoint material along with the text portion of the syllabus. At the end of this course, registrants should be able to readily recognize the newer entities and have a new appreciation for entities with which they should already be familiar. This course will be of value to general pathologists, pathology residents and pathologists with special interest in breast pathology.

(LAST SCHEDULED PRESENTATION) This course may be used for CME credits or SAM credits.