Benign mimickers of malignant breast lesions

Breast pathology is filled with pitfalls, including underdiagnosis of bland-appearing lesions, both invasive and non-invasive, misdiagnosis of malignant lesions as belonging to the wrong subgroup, for example, calling LCIS as DCIS or missing the metaplastic component of an invasive lesion, and overdiagnosis of benign lesions as malignancy. While each is a sin of varying severity, the overdiagnosis of benign lesions can be the most scarring, especially in this age where Angelina Jolie׳s prophylactic mastectomy is the headline news and patients are pushing for aggressive preventive treatment. In this review, we will consider some of the more common benign lesions and the malignant counterpart that they mimic, with the goal of identifying characteristic features that will lead to the correct diagnosis. Much of the discussions will center around the assessment of core biopsies, as smaller tissue volume is most often contributory to overcalling benign lesions.