Review ArticlesImmunohistochemistry in the Diagnostic Evaluation of Breast LesionsHicks, David G. MDAuthor Information University of Rochester Medical Center, Elmwood Avenue, Rochester, NY The author declares no conflict of interest. Reprints: David G. Hicks, MD, University of Rochester Medical Center, 601 Elmwood Avenue, Box 626, Rochester, NY 14642 (e-mail: [email protected]). Received July 5, 2011 Accepted July 6, 2011 Applied Immunohistochemistry & Molecular Morphology: December 2011 - Volume 19 - Issue 6 - p 501-505 doi: 10.1097/PAI.0b013e31822c8a48 Buy Metrics Abstract Most diagnoses in breast pathology can be rendered after careful evaluation of a high quality hematoxylin and eosin-stained tissue section. However, a significant number of both benign and malignant lesions can show variable morphologic patterns and significant histologic overlap, leading to diagnostic uncertainty. These challenges and complexities have opened the door to an expanding role for immunohistochemistry (IHC) as an important diagnostic adjunct for solving frequently encountered problems in breast pathology. Although IHC has proven to be a powerful tool in helping to resolve difficult cases, the results of such studies should always be carefully interpreted within the morphologic context for each lesion. This article will briefly review some of the more common circumstances in which IHC has been shown to be useful in diagnostic breast pathology. © 2011 Lippincott Williams & Wilkins, Inc.