Benign breast papillomas without atypia diagnosed with core needle biopsy: Outcome of surgical excision and imaging follow-up

Purpose: To evaluate the surgical upgrade rate to malignancy and high-risk lesions in cases of papilloma without atypia diagnosed with imaging-guided percutaneous core needle biopsy (CNB) and to determine whether any lesion imaging features, biopsy techniques, and pathological factors can predict lesion upgrade to help guide clinical management. Materials and methods: Benign papillomas without atypia (n = 399) diagnosed with CNB were retrospectively reviewed. The surgical upgrade rate to malignancy or high-risk lesion (atypical ductal hyperplasia, atypical lobular hyperplasia, lobular carcinoma in-situ, flat epithelial atypia and atypical papilloma) was determined. Detection modality (i.e. mammography, ultrasonography (US), magnetic resonance imaging (MRI)), lesion type and size, biopsy-guidance modality (US, stereotactic, MRI), biopsy needle size (<14 G vs ≥14 G), use of vacuum assistance, and presenting symptoms were statistically analyzed. The reference standard for evaluation of upgrade was either excision or at least 24 months of imaging follow-up. Chi Square test and Fisher exact tests were performed for categorical variables, and the Mann-Whitney-U test was used for continuous variables. Results: Ultrasound was the predominant biopsy modality (78.4 %, p < 0.001). Of the 399 benign papilloma lesions in 329 women, 239 (59.9 %) were excised and 93 others were followed for at least 24 months (total of 332). Of these 332 lesions, 7 (2.1 %) were upgraded to ductal carcinoma in-situ and 41 (12.3 %) to high-risk lesions at excision. Larger lesion size (≥15 mm, p = 0.009), smaller biopsy needle size (≥14 G, p = 0.027), and use of spring-loaded biopsy device (p = 0.012) were significantly associated with upgrade to atypia. Only lesion size (≥15 mm, p = 0.02) was associated with upgrade to cancer. Conclusion: Upgrade to malignancy of biopsy-proven benign papillomas without atypia at the time of surgery was sufficiently low (2.1 %) to support non-operative management. Surgery may be performed for selected cases- those with larger lesion size and those whose biopsies were performed with smaller spring-loaded biopsy needles.