Large core needle biopsies using stereotactic mammography or ultrasound guidance are now commonly performed as the initial diagnostic approach to nonpalpable breast lesions. Although the subsequent management of patients with invasive cancer, ductal carcinoma in situ, and most benign lesions diagnosed on core needle biopsy specimens is straightforward, certain nonmalignant lesions pose dilemmas with regard to the most appropriate clinical management following core needle biopsy. The purpose of this article is to review the available data regarding several nonmalignant breast lesions, which when encountered in core needle biopsy specimens raise repeated management questions. These include atypical ductal hyperplasia, lobular neoplasia (atypical lobular hyperplasia and lobular carcinoma in situ), papillary lesions, radial scars, fibroepithelial lesions, mucocele-like lesions, and columnar cell lesions.