Background: The objective of this study was to propose managements for breast papillomas of 10 mm or smaller initially diagnosed at core biopsy. Method: We reviewed the data of patients in our center from 2004 to 2013. 116 lesions of 10 mm or smaller as measured by ultrasound (US) were diagnosed as papillomas at core needle biopsy (CNB) or vacuum-assisted biopsy (VAB). 74 of the papillomas diagnosed by CNB were surgically excised, the others were followed by imaging surveillance. Result: 13 of 116 lesions were found to be malignant, with an upgrade rate of 11.2%. Analyzing the difference between malignant and nonmalignant lesions, patients with malignant lesions were older than those with nonmalignant lesions (56.6 vs. 46.6 years, p = 0.002). Papillomas with atypia had a significantly higher upgrade rate than without, both in the surgical results (p = 0.030) and overall (p = 0.0392). None of 16 papillomas larger than 5 mm upgraded to malignancy. Breast papillomas diagnosed by CNB had a significantly higher upgrade rate (16.5%) than those diagnosed by VAB (0%) (p = 0.021). Conclusion: Our finding suggests that breast papillomas of 6-10 mm at initial CNB need additional surgical excision, but imaging surveillance may be suitable for papillomas no larger than 5 mm and papillomas detected by VAB.