Risk of malignancy in papillary neoplasms of the breast.

PURPOSE: In recent years, routine excision of papillary neoplasms (PN) of the breast has been questioned and controversy exists over when excision is necessary. The aim of this study was to evaluate the upstage rate to malignancy of core needle biopsy (CNB) diagnosed PNs from multiple diagnostic centers in our area and to identify factors predictive of malignancy. METHODS: Patients presenting to our surgical center between 2013 and 2017 for excision of CNB PN were evaluated. The primary endpoint was upstage to malignancy. The association of age, diagnostic center where CNB performed, type of CNB, palpability, discharge, clinical exam size, imaging size, family history of breast cancer, and presence of atypia, as risk factors for upstaging to cancer were also evaluated. RESULTS: Of the 317 PN cases, 83 upstaged to malignancy following surgical excision. 77% of patients with CNB of Atypical PN upstaged, 39% of PN with concurrent atypical ductal hyperplasia, and 0% of PN with concurrent atypical lobular hyperplasia/flat epithelial atypia. Of the 206 non-atypical PNs on CNB, 3.4% upstaged to malignancy, but further review demonstrated a 1% upstage rate when atypia excluded. Factors found to be associated with malignancy included: older patient age, larger size, and presence of atypia. CONCLUSION: We recommend excision of PN with atypia, concurrent cancerous lesion, or radiologic-pathologic non-concordance, and serial imaging follow up may be considered for image detected PN, less than 1 cm, with no atypia.