44 Background: Papillary lesions of the breast are frequently diagnosed on core needle biopsy (CNB). The ability to distinguish benign from atypical/malignant papillary lesions is limited by the representative nature of the biopsy method; thus follow-up excision is usually recommended. We aimed to determine if larger CNB samples can more reliably predict the true benign nature of a papillary lesion, thereby sparing certain patients a formal surgical excision. Methods: We reviewed medical records of 53 female patients diagnosed with histologically benign papillary lesions on CNB from 2000 to 2010, who subsequently underwent surgical excision. Pathology slides of the CNB were reviewed to document the benign histologic features of the papilloma, the number of cores sampled and the area of tissue biopsied (mm2). Statistical analysis was performed to identify the characteristics of the CNB that were associated with retention of benign histology on excision. Results: Atypical ductal hyperplasia (ADH) and carcinoma were identified in 6% (3/53) and 8% (4/53) of papillary lesions, respectively, when excised. Clinical and radiographic characteristics did not distinguish the ADH/malignant lesions from benign papillomas. The CNB needle sizes ranged from 9- to 18-gauge (median 14). The number of cores sampled ranged from 3-16 (mean 4.5). Patients with benign excisions had a significantly larger area of tissue sampled by CNB than those found to have ADH/malignant lesions on excision (mean ± SD: 95.6 ± 101.2 vs. 41.7 ± 21.9, respectively, p=0.003). By logistic regression, CNB tissue samples consisting of ≥7 cores, or measuring >96 mm2 in aggregate, had a negative predictive value for ADH/malignancy of 100% (AUC of 0.69 and 0.68, respectively). Conclusions: Although no clinical or radiologic features distinguished benign from pathologically significant papillary lesions, larger sample sizes significantly improved the predictive value of benign histology on CNB. A papilloma sampled by ≥ 7 cores or > 96 mm2 showing benign histology at CNB, retained benign features upon excision. Close surveillance may be a reasonable option for patients whose benign papillomas are generously sampled at the time of CNB.
Flat Epithelial Atypia of the Breast on Core Needle Biopsy: An Indication for Surgical Excision
