[Diagnostic immunohistochemistry of breast epithelial lesions]

Routine H&E sections are sufficient for diagnosis of the vast majority of breast lesions. Development of mammography mass screening and widespread use of preoperative needle biopsy diagnosis have led to diagnostic difficulties for pathologists. The samples are smaller and more and more preinvasive lesions are seen. It is mainly in those situations that immunohistochemistry (IHC) can efficiently back up histopathology. This review details the main applications of diagnostic IHC in breast pathology. The advantages of IHC in various clinical situations are discussed diagnosis of benign breast lesions mimicking malignancy, distinction between simple type ductal hyperplasia and atypical hyperplasia or ductal in situ carcinoma, confirmation of malignancy, distinction between lobular and ductal carcinoma, identification of specific histological subtypes, and, diagnosis of intra and extra mammary metastases.