Original ArticlesFlat Epithelial Atypia in Breast Core Needle Biopsies With Radiologic-Pathologic Concordance Is Excision Necessary?Grabenstetter, Anne MD*; Brennan, Sandra MD†; Salagean, Elena D. MD*; Morrow, Monica MD‡; Brogi, Edi MD, PhD*Author Information Departments of *Pathology †Radiology ‡Surgery, Memorial Sloan Kettering Cancer Center, New York, NY Presented in part at the United States and Canadian Academy of Pathology (USCAP) Annual Conference at National Harbor, MD in March 2019. Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Correspondence: Anne Grabenstetter, MD, Department of Pathology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (e-mail: email@example.com). Online date: October 11, 2019 The American Journal of Surgical Pathology: February 2020 - Volume 44 - Issue 2 - p 182-190 doi: 10.1097/PAS.0000000000001385 Buy Metrics Abstract Flat epithelial atypia (FEA) is an alteration of terminal duct lobular units by a proliferation of ductal epithelium with low-grade atypia. No consensus exists on whether the diagnosis of FEA in core needle biopsy (CNB) requires excision (EXC). We retrospectively identified all in-house CNBs obtained between January 2012 and July 2018 with FEA. We reviewed all CNB slides and assessed radiologic-pathologic concordance. An upgrade was defined as invasive carcinoma (IC) and/or ductal carcinoma in situ in the EXC. The EXC slides of all upgraded cases were rereviewed. Out of ∼15,700 consecutive CNBs in the study period, 106 CNBs from 106 patients yielded FEA alone or with classic lobular neoplasia (LN). We excluded 52 CNBs (40 patients with prior/concurrent carcinoma and 12 without EXC). After rereview, we reclassified 14 cases (2 marked nuclear atypia, 10 focal atypical ductal hyperplasia, 2 benign). The final FEA study cohort consisted of 40 CNBs from 40 women. The CNB targeted mammographic calcifications in 36 (90%) cases, magnetic resonance imaging nonmass enhancement in 3 (8%), and 1 (2%) sonographic mass. All CNBs were deemed radiologic-pathologic concordant. FEA was present alone in 34 CNBs and with LN in 6. EXC yielded 2 low-grade IC, each spanning <2 mm, identified in tissue sections without biopsy site changes. The remaining 38 cases had no upgrade. Classic LN did not affect the upgrade. The upgrade rate of FEA was 5%; both minute, low-grade “incidental” IC. We conclude that nonsurgical management may be considered in patients without prior/concurrent carcinoma and radiologic-pathologic concordant CNB diagnosis of FEA. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.