Analysis of Discordant Histologically Benign Breast Lesions and Predictive Factors Associated with True Discordance on Imaging

Abstract

Introduction: Discordant benign breast lesions are suspicious for malignancy on imaging but show benign histology on initial biopsy. These lesions require further histological workup. This study sought to determine the frequency of discordant benign lesions and the rate of true discordance among them, and to identify predictive factors associated with true discordance. Methods: Clinical, radiological, and pathological data on all discordant benign breast lesions biopsied between 2012 and 2021 were retrieved from the departmental database of a Hong Kong hospital. Rate of discordant benign lesions, true and false discordance rates, and proportion of high-risk and benign lesions among false discordance were calculated. If the discordant benign lesion was found to be malignant in repeat percutaneous biopsy or excisional biopsy, it was true discordance. If a lesion's benignity was confirmed with excisional biopsy, it was false discordance. Univariate analysis was performed followed by multivariable logistic regression analysis to identify independent predictors associated with true discordance. Results: A total of 3080 breast biopsies were performed during the study period, of which 64 lesions (2.1%) were discordant benign lesions. Among 55 lesions with available additional workup results, 17 lesions (30.9%) were true discordant and 38 (69.1%) were false discordant. Nine (23.7%) of the false discordant lesions were high-risk lesions on final pathology. Older age (p = 0.019), presence of symptoms (p = 0.046), BI-RADS category 5 (p = 0.028), presence of microcalcifications with suspicious morphology (p = 0.047), and presence of architectural distortion (p = 0.04) were identified as independent predictors of true discordance. Conclusion:The high true discordance rate confirmed the importance of further histological workup in discordant benign breast lesions.