Thyroid fine needle aspirate: a post-Bethesda update.

The Bethesda system for reporting thyroid cytopathology formulated in 2007 has standardized reporting of thyroid cytology specimens and streamlined management algorithms. Although 3 of the categories (benign, malignant, and nondiagnostic) are standardized and improved, the remaining 3 (follicular lesion of undetermined significance, follicular neoplasm, and suspicious for malignancy) remain fraught with interobserver variability and uncertainty regarding management algorithms. Recent and ongoing morphologic and molecular studies that aim to resolve these issues are summarized.