Effectuation of International Academy of Cytology Yokahama Reporting System of Breast Cytology to Assess Malignancy Risk and Accuracy

INTRODUCTION: Recently the International Academy of Cytology (IAC) proposed a new Yokahama reporting system for breast fine-needle aspiration cytology (2019) in order to standardize reporting pattern and to link cytology reporting to management algorithms. AIMS AND OBJECTIVES: To categorize the samples according to the newly proposed IAC Yokahama reporting system of breast cytology and to assess diagnostic accuracy and corresponding risk of malignancy (ROM) for each category. MATERIALS AND METHODS: This is a retrospective study of breast cytology cases done at Department of Pathology. The slides are retrieved from pathology archives and classified using a recently proposed IAC, Yokahama reporting system of breast cytology into five categories. The risk of malignancy, sensitivity, specificity, and diagnostic accuracy were estimated on the basis of the final histopathological diagnosis. RESULTS: Of the 386 cases of breast FNAC, 226 (55.55%) had the corresponding histological diagnosis. The respective ROM for each category was 22.22% for category 1 (insufficient material), 5.32% for category 2 (benign), 26.31% for category 3 (atypical), 100% for category 4 (suspicious for malignancy), and 100 % category 5 (malignant). Malignant cases were considered only when positive tests, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 89.66%, 100%, 100%, 90.2%, and 94.69%, respectively. CONCLUSIONS: The present study showed statistically significant sensitivity, specificity, and diagnostic accuracy, especially with malignant cases. Hence, using the IAC Yokahama reporting system of breast cytology is effective to standardize the reporting in various institutes and provide clear guidelines to clinician for further management.