Assessment of risk of malignancy and accuracy of breast fine needle asspiration specimens using the International Academy of Cytology Yokohama System

Abstract

Background: Fine-needle aspiration biopsy is the most commonly used procedure due to its cost-effectiveness and reliability. This study aimed to categorize breast specimens according to the International Academy of Cytology Yokohama classification system and to assess and calculate the risk of malignancy, diagnostic accuracy as compared to histopathological diagnosis, identify the system’s pitfalls, and evaluate its implications in low-resource or financially constrained settings.

Materials and Methods: A total of 160 breast were studied over a period of six months in patients presenting with palpable breast lumps. The cytology slides were re-categorized using the IAC Yokohama system into five categories. Follow-up histopathology was available for 102 cases.

Results: FNAB specimens were categorized according to the IAC Yokohama system as: insufficient 6.2% (n = 4), benign 72.5% (n = 70), atypical 6.2% (n = 8), suspicious of malignancy 2.5% (n = 2), and malignant 12.5% (n = 18). The risk of malignancy in the benign category was 2%, and in the malignant category was 100%, while sensitivity of the fine needle aspiration cytology was: 90.9%, specificity: 100%, positive predictive value: 100%, negative predictive value 97.1%, and the diagnostic accuracy 97.7%.

Conclusions: Yokohama system aligns well with the histopathological diagnosis, with histopathology considered the gold standard. The IAC Yokohama protocol has shown significant improvement and standardization in the reporting of breast.