Background: Clinical management of benign papilloma of breast diagnosed on core needle biopsy (CNB) remains controversy. Factors associated with malignant upgrading in CNB are inconclusive.

Objective: To identify factors associated with malignant upgrading in CNB of benign papillary lesion of the breast.

Materials and Methods: A retrospective review study of 423 papillary lesions in 404 patients diagnosed on imaged-guided CNB was included. Total 351 lesions were benign papilloma and 220 lesions were surgically removed. An upgrade rate was noted when
surgical specimen found ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC) or other malignancy. Clinical, radiographic
and pathological variables were analyzed in order to find factors associated with malignant upgrading.

Results: Of the 220 benign papillary lesions on CNB, excision specimens revealed 163 benign papilloma, 6 atypical papilloma, 5 DCIS, and 1 IDC. Malignant upgrade rate was 3.42%. Age >50, thin/arborizing fibrovascular core and intralesional atypia are factors
associated with malignancy on excision specimens.

Conclusion: Papillary lesion of the breast could be managed by clinical follow-up without excision. However, factors associated with malignant upgrading in CNB of benign papillary lesion of the breast are patients aged >50, thin/arborizing/mix fibrovascular core and intralesional atypia.

Keywords: Breast, Core needle biopsy, Malignant upgrading, Papillary lesion