Mammographic Breast Asymmetry: Demographic, Clinical, Imaging, and Pathological Characteristics

Background: Mammographic breast asymmetries comprise a spectrum of findings that do not conform to the definition of a mass.They are most often benign but may also represent an underlying malignancy.This study aimed to determine the frequency, demographic and clinical profile, and imaging characteristics of mammographic asymmetries (asymmetry, focal, and global), and to assess the proportion of malignancy and the clinical and imaging features associated with malignancy.Methods: This prospective study was conducted in the Department of Radiodiagnosis, Dr. Ram Manohar Lohia Institute of Medical Sciences, from May 2, 2020, to April 30, 2021.Women undergoing bilateral mammography whose mammograms demonstrated an asymmetry were included.Demographic and clinical information was recorded, followed by assessment of mammographic breast composition, type and location of asymmetry, and associated imaging findings.Digital breast tomosynthesis and targeted high-resolution ultrasonography were performed for further evaluation.The appropriate Breast Imaging Reporting and Data System (BI-RADS) category was assigned after complete imaging assessment.Lesions categorized as BI-RADS 4 or higher underwent fine-needle aspiration cytology or biopsy for pathological diagnosis.Cases assigned BI-RADS 1-3 were followed according to the prescribed imaging follow-up protocol.Results: Of 1,324 bilateral mammographic examinations, mammographic asymmetry was identified in 120 (9.1%) examinations.Asymmetry was observed in 36 (30.0%) cases, global asymmetry in 16 (13.3%),and focal asymmetry in 68 (56.7%).Targeted ultrasonography demonstrated no focal abnormality in 60 (50.0%) cases, benign/probably benign findings in 36 (30.0%), and suspicious findings in 24 (20.0%).Fine-needle aspiration cytology or biopsy was performed in 24 (20.0%)cases, of which 20 (83.3%) were diagnosed as malignant.Conclusion: Mammographic asymmetries are frequently benign but may occasionally represent the only imaging indication of underlying malignancy.Complete mammographic and sonographic evaluation, followed by appropriate BI-RADS assessment, is important for determining the need for pathological evaluation or imaging follow-up.