Risk factors for malignancy in benign papillomas of the breast on core needle biopsy

Background: This study was designed to evaluate the clinical and pathologic parameters of benign papillomas diagnosed on core needle biopsy (CNB) and predict malignancy risk after surgical excision. Methods: We retrospectively reviewed clinicopathologic findings for 160 CNB-diagnosed benign papillomas followed by surgical excision from 154 patients. Results: Ten (6.3%) of the excised lesions were diagnosed as malignant. Univariate analysis showed that those that were palpable on physical examination, detected as a mass on mammography, or >1 cm on sonography were significantly associated with malignancy. In multivariate analysis, lesions that were palpable (odds ratio (OR), 29.2; 95% confidence interval (CI), 4.06-209.58; P = 0.001) or detected as a mass (OR, 5.68; 95% CI 1.08-29.87; P = 0.04) remained significantly associated with malignancy. In a CART analysis, including all variables, lesions that were palpable and associated with a mass on mammogram were confirmed as malignant. Conclusions: Breast lesions diagnosed as benign papillomas on CNB had a 6.3% risk of being malignant. The risk was highest for lesions that were palpable and detectable as a mass on a mammogram. In addition, the low-risk patients avoid immediate surgical excision, although they should be followed carefully.