Benign papilloma without atypia diagnosed at US-guided 14-gauge core-needle biopsy: Clinical and US features predictive of upgrade to malignancy

Purpose: To evaluate the diagnostic accuracy of ultrasonographically (US)-guided 14-gauge core-needle biopsy (CNB) for benign papilloma without atypia and to determine whether clinical and radiologic features could be used to predict an upgrade to malignancy. Materials and Methods: This was an institutional review board-approved retrospective study, with a waiver of informed consent. The histologic results of US-guided CNB procedures performed from January 2006 through January 2009 were reviewed. A total of 160 benign papillomas without atypia that were diagnosed at CNB and excised surgically in 143 women (age range, 19-77 years) were assessed. Medical records and sonograms in the women were reviewed. Two radiologists working in consensus correlated imaging findings with the biopsy result to determine concordance. For the upgrade to malignancy after excision, malignant lesions were compared with nonmalignant lesions for the collected clinical and radiologic variables, which included patient age, lesion size, and lesion distance from the nipple, by using the χ² or Fisher exact test for categoric variables and the Mann-Whitney U test for continuous variables. Results: Eight (5.0%) of 160 papillomas were upgraded to malignancy. Lesions that were 1 cm or larger (seven [11%] of 63) showed a higher upgrade rate than lesions that were smaller than 1 cm (one [1%] of 97) (P =.006). The upgrade rate was higher in patients aged 50 years or older (six [16%] of 37) than in patients younger than 50 years (two [2%] of 123) (P =.002). Lesions that were 3 cm or farther from the nipple (four [13%] of 31) showed a higher upgrade rate than lesions that were less than 3 cm from the nipple (four [3.1%] of 129) (P =.046). Upgrade rates for Breast Imaging Reporting and Data System (BI-RADS) category 3, 4a, 4b, 4c, and 5 lesions were 0%, 2.5%, 6%, 27%, and 25%, respectively (P =.010). Conclusion: At US-guided 14-gauge CNB, benign papilloma without atypia could be diagnosed accurately. Discordance between imaging and pathology results, as well as patient age of 50 years or older, lesion size of 1 cm or greater, lesion distance from the nipple of 3 cm or greater, and BI-RADS category may be helpful in predicting the possibility of upgrade to malignancy.