Our aim was to determine upgrade rates of pure flat epithelial atypia (FEA) to malignancy and higher-risk lesions and to identify patients with FEA at low risk for upgrade. Medical chart review from 2007 to 2016 identified 208 consecutive patients with pure FEA diagnosed by image-guided core needle biopsy who underwent surgical excision (96.2% 200 of 208) or had at least 2 years of imaging follow-up (3.8% 8 of 208). Medical records were reviewed for risk factors and surgical outcomes. Overall upgrade rate of FEA to malignancy was 2.4% (5 of 208). All 5 upgraded cases were ductal carcinoma in situ at operation. The upgrade rate to atypical ductal hyperplasia, lobular carcinoma in situ, or atypical lobular hyperplasia was 29.8% (62 of 208). The FEA lesions in patients with a genetic mutation were more likely to upgrade to malignancy than FEA lesions in patients without a genetic mutation (33.3% 1 of 3 vs 2.0% 4 of 205; p < 0.01). The FEA lesions in patients with a personal history of breast cancer were more likely to upgrade to higher-risk lesions than those without a personal history (47.8% 11 of 23 vs 27.6% 51 of 185; p = 0.046) but were not more likely to be upgraded to malignancy (0% 0 of 23 vs 2.7% 5 of 185; p = 0.42). The overall risk of upgrade of FEA to malignancy is low at 2.4%; however, the upgrade rate to a higher-risk lesion is nearly 30%. Surveillance rather than surgical excision of FEA can be a reasonable option for patients without a genetic mutation who opt against chemoprevention.