Standardized reporting of breast FNAC using the International Academy of Cytology Yokohama system and its comparison with histopathology: a cross-sectional study.

Introduction: The International Academy of Cytology (IAC) has developed a comprehensive and systematic method that defines five categories for reporting breast fine needle aspiration cytology. These categories stratify breast lesions by their risk of malignancy, providing guidance on management for each category. The aim of the study is to analyze the diagnostic utility of the IAC Yokohama system in breast cytology reporting with histopathological correlation.

Methods: This was a cross-sectional observational study. The study included 55 patients with clinically suspected breast lumps who underwent Fine Needle Aspiration Cytology for provisional diagnosis, which was later confirmed by corresponding excisional biopsy and histopathology. The collected data following Fine Needle Aspiration Cytology (FNAC) and histopathology were entered into Microsoft Office Excel software 13. Data analysis was performed using SPSS 16. For diagnostic measurement, sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were calculated. The probability of significance was set at the 5% level.

Results: Among 55 cases of breast lesions on cytopathology as per the International Academy of Cytology Yokohama System, none of the cases were categorized as Insufficient (C1). Twenty-five cases (45.5%) were categorized as C2 (benign), 5 cases (9.1%) were categorized as C3 (atypia, probably benign), 4 cases (7.3%) were categorized as C4 (suspicious for malignancy), and 21 cases (38.3%) were categorized as C5 (malignant). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for cytopathology compared with histopathology were 86.21% (95% CI: 73.76%-98.66%), 100% (95% CI: 100%-100%), 100% (95% CI: 100%-100%), 86.67% (95% CI: 74.29%-99.05%), and 92.7% (95% CI: 85.54%-99.93%), respectively.

Conclusion: The IAC Yokohama system for reporting breast fine needle aspiration cytopathology effectively stratifies patients into five categories and has high sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy with regard to the gold standard histopathology.