AIM:To ascertain the negative predictive value (NPV) for atypia and malignancy of 14 G core biopsy of papillomas and to determine whether lesion type influences the likelihood of malignancy at lesion excision. MATERIALS AND METHODS:Ninety-six lesions with a 14 G core biopsy diagnosis of benign papilloma without atypia in 95 women were included. The imaging features (mass or microcalcification), biopsy mode, and number of core samples taken were documented. All patients subsequently underwent lesion excision with either extensive vacuum-assisted biopsy (VAB; 72 lesions) or surgery (24 lesions). Mammographic follow-up of at least 2 years was available for 32 lesions that were benign at VAB. RESULTS:Atypia or malignancy was found more commonly in association with microcalcification (six of 29 lesions: 21%; median number of nine 14 G cores) than a mass (five of 67 lesions: 7%; median number of three 14 G cores), although the difference does not reach statistical significance (p = 0.088). The NPV of a 14 G core biopsy diagnosis of papilloma for atypia or malignancy is 89% (85/96). Disease underestimation may be more common in microcalcification lesions despite the greater number of cores obtained. CONCLUSION:Excision (using VAB or surgically) of all papillomas diagnosed as benign on 14 G needle core biopsy is recommended. Surgery may be more appropriate than VAB for some microcalcification lesions unless they are small and can be confidently removed in their entirety using VAB.