Utility of Yokohama system for classification of breast FNA

• Meenakshi Swain,  
• Shyamala Nedunuri*

Abstract

Introduction: Breast carcinoma is the most common malignancy among women globally. FNA is used as an important diagnostic tool as a part of triple assessment. The application of the IAC Yokohama system in breast cytology standardises reporting and also allows the calculation of risk of malignancy (ROM). Objectives: To categorize all FNAC specimens according to the newly proposed IAC Yokohama reporting system for breast cytology. The ROM was determined for each category, sensitivity, specificity, negative and positive predictive values were evaluated to estimate the diagnostic accuracy of each category and inter-observer variability. Materials and methods: 105 cases of breast FNACs were classified according to the IAC Yokohama system. The study was conducted over a period of 4 years and 9 months retrospectively from August 2018 to May2023. All FNACs were correlated with corresponding histology, but in most studies correlation of FNACs with histopathology was not possible in all cases because many were lost to follow-up. ROM for each category, Specificity, sensitivity, diagnostic accuracy, negative predictive value, positive predictive value and interobserver variability of FNAC were calculated. p-value was also calculated. Results: Out of 105 breast FNACs, the category wise distribution from category 1 to 5, were category 1:4(3.8%), category2: 20(19.1%), category3: 16(15.2%), category4:5(4.8%) and category 5: 60(57.1%) respectively. The sensitivity, specificity, positive and negative predictive value and diagnostic accuracy was 90.3%, 100%, 100%, 82.5% and 93.3% respectively. Conclusion: The Yokohama system has standardized, broadly used, and well-understood diagnostic categories, with clear criteria for inclusion in a category and appears to be reproducible by most cytopathologists.

Keywords

Yokohama, Breast FNAC, ROM, Interobserver variability

Ahead of Print Date : 2024-04-01