Cytological Grading of Palpable Breast Lesions: Comparative Analysis of Masood, Modified Masood, and Yokohama system with Cytohistological Correlation at a Newly Established Tertiary Care Center in South India

Abstract Background: Fine-needle aspiration cytology (FNAC) is a minimally invasive tool for preoperative evaluation of palpable breast lesions. Cytological scoring systems—including the International Academy of Cytologists Yokohama System (YS), Masood Scoring Index (MSI), and Modified Masood Scoring Index (MMSI)—facilitate subcategorization of lesions and risk assessment. Aim: To classify breast FNAC smears according to YS, MSI, and MMSI and evaluate diagnostic performance through cytohistological concordance and other performance indicators. Materials and Methods: This retrospective cross-sectional study included 884 FNAC cases, out of which the cytohistological correlation was available in 682 cases from April 2020 to April 2024 at a tertiary care center in South India. Smears were categorized using YS, MSI, and MMSI. Sensitivity, specificity, positive predictive value, negative predictive value, diagnostic accuracy (DA), and Cohen’s kappa for concordance were calculated. Results: Mean patient age was 44.75 years (range 12–84), with a female-to-male ratio of 30:1. Cytohistological concordance was highest for MMSI (kappa = 0.874), followed by YS (0.853) and MSI (0.839). Intersystem concordance was highest between MMSI and MSI (0.884), followed by MMSI and YS (0.845), while it was lowest for MSI and YS (0.823). YS demonstrated the highest specificity (93.6%) and DA (95.5%) for malignant lesions. Risk of malignancy was highest in categories C4 and C5. Conclusion: MMSI shows superior concordance for benign and borderline lesions, while YS provides higher accuracy for malignant cases. Standardized reporting using these systems enhances reproducibility, facilitates clinical management, and aligns with lesion-specific risk stratification.