Interobserver agreement and risk of malignancy using the International Academy of Cytology Yokohama System for reporting breast FNA biopsy in a liquid-based exclusive cohort.

Interobserver agreement is excellent using the five YS categories in LBC. Lack of cellularity and incomplete architectural features were barriers to perfect agreement. Established pitfalls in the interpretation of LBC were cause for atypical diagnoses. Continuous training and education are recommended to avoid misdiagnosis because of the nonconventional cytomorphologic features of LBC and to improve inadequate and atypical rates within YS.