Patterns of lobular carcinoma in situ and their diagnostic mimics in core needle biopsies

Abstract

Lobular carcinoma in situ (LCIS) of the breast may exhibit a spectrum of morphologic growth patterns and may also colonize underlying benign breast lesions. This diversity in appearance can create diagnostic challenges, especially in core needle biopsy specimens. Some LCIS variants may mimic ductal carcinoma in situ or invasive carcinoma. Furthermore, some LCIS variants are frequently associated with adjacent invasive lobular carcinoma. Therefore, familiarity with this morphologic spectrum is essential when evaluating LCIS in core needle biopsies. This review focuses on histologic and immunohistochemical features that help to distinguish unusual patterns of LCIS from the lesions they mimic. © 2009 Lippincott Williams & Wilkins, Inc.