Management of benign papilloma without atypia diagnosed at ultrasound-guided core needle biopsy: Scoring system for predicting malignancy.

Background: The management of benign intraductal papilloma diagnosed on core needle biopsy (CNB) remains unclear. This study was designed to evaluate factors predicting malignancy in patients diagnosed with benign papilloma without atypia at ultrasound-guided CNB and to develop a scoring system predicting malignancy based on clinical, radiological and pathological factors on further excisional biopsy.

Methods: The study enrolled patients diagnosed with benign papillomas (including benign and atypical papillary lesions) at CNB. Multivariate analysis was used to identify relevant clinical, radiological and pathological factors that may predict malignancy.

Results: A total of 520 CNBs were diagnosed with benign or atypical papilloma. Of these, 452 were benign papilloma without atypia. Of the 250 lesions subsequently excised surgically from 234 women, 17 (6.8%) were diagnosed with malignancy. Multivariate analysis revealed that bloody nipple discharge, size on imaging ≥15 mm, BI-RADS≥4b, peripheral location and palpability were independent predictors of malignancy. A scoring system was developed based on logistic regression models and beta coefficients for each variable. The area under the ROC curve was 0.947 (95% CI: 0.913-0.981, p < 0.001) and a negative predictive value was 100%. In a validation set of 62 patients, an area under the ROC curve was 0.926 (95% CI: 0.857-0.995, p < 0.001).

Conclusions: A scoring system predicting malignancy in patients diagnosed by CNB with benign papilloma without atypia was developed. This system was able to identify a subset of patients with lesions likely to be benign, indicating that imaging follow-up rather than surgical excision may be appropriate.