A retrospective analysis of 512 cases of breast fine needle aspiration cytology utilizing the recently proposed IAC Yokohama system for reporting breast cytopathology.

Abstract

Recently the International Academy of Cytology (IAC) introduced a new reporting system for breast fine-needle aspiration cytology that classifies cytologic diagnoses into five-categories: (I) insufficient material, (II) benign, (III) atypical, (IV) suspicious of malignancy, and (V) malignant. The current study was undertaken to categorize the breast lesions utilizing the newly proposed IAC Yokohama classification system and evaluate the risk of malignancy (ROM) for respective categories and the diagnostic yield of this technique. All FNAs of breast lesions over 2.5 years were categorized retrospectively using the newly proposed IAC Yokohama reporting system. The ROM was calculated along with sensitivity, specificity, positive and negative predictive value, diagnostic accuracy, false positive, and false-negative rate using the histological diagnosis as the gold standard. The 512 cases were distributed as follows: Category I (insufficient material) 7.4%, Category II (benign) 74%, Category III (atypical) 5.7%, Category IV(suspicious) 1.4%, and Category V (malignant) 11.5%. Histopathological correlation was available in 285 (55.7%) cases. The respective ROM calculated was 33.3%, 0.5%, 13.3%, 83.3%, and 100% for Category I-V. The Sensitivity, Specificity, Positive and Negative Predictive Value, and Diagnostic accuracy were 95%, 99.5%, 98.27%, 98.6, and 98.5% respectively. Despite previous attempts to establish a standardized diagnostic terminology, there has been a lack of a single internationally approved standardized reporting system allowing substantial diagnostic clarity and incorporating distinct diagnostic categories, each linked with a specific ROM and recommended management. This System also provides enhanced communication between pathologists and attending clinicians for the benefit of the patient.