The Yokohama Paradigm: Assessing Fine-Needle Aspiration Biopsy for Breast Lesions with Enhanced Diagnostic Precision

Abstract

Background: Breast cancer is the most common malignancy in women, with rising incidence in India. FNAB is a key diagnostic tool, but reporting inconsistencies exist. The IAC Yokohama System standardizes FNAB cytology, improving clinical communication and patient management.
Methods: A cross-sectional study at SCB Medical College (2020-2022) included 210 patients with breast lumps. FNAB was performed, and smears were stained with H&E, Pap, and Diff-Quik. Diagnoses followed the Yokohama System, with histopathological correlation. Statistical analysis assessed diagnostic accuracy, sensitivity, specificity, PPV, NPV, and risk of malignancy (ROM).
Results & Discussion: Among 210 FNA procedures, the majority of cases occurred in the 31-40-year age group, with the upper outer quadrant being the most common site (40%). Benign lesions (47.6%) were most frequent, followed by malignant cases (43.8%). The risk of malignancy ranged from 17.44% (Category II) to 97.4% (Category V). Sensitivity and specificity were assessed against histopathology, with statistical significance (χ² = 138.88, p < 0.05). FNAB demonstrated high diagnostic accuracy, aiding in distinguishing benign from malignant lesions. The five-tier Yokohama classification improved clinician-pathologist communication, risk assessment, and preoperative decision-making.
Conclusion: The Yokohama System enhances FNAB’s reliability, supporting its wider adoption to improve breast cancer diagnosis and patient outcomes.