The 2023 Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) redefines Atypia of Undetermined Significance (AUS) by introducing subclassification into AUS with nuclear atypia and AUS-other. This change reflects growing evidence that the risk of malignancy is subtype-dependent. For endocrine surgeons, this means that cytology can no longer be interpreted in isolation: AUS subtypes must be integrated wit...