The 2017 Bethesda System for Reporting Thyroid Cytopathology

Edmund S Cibas; Syed Z Ali

doi:10.1016/j.jasc.2017.09.002

The 2017 Bethesda System for Reporting Thyroid Cytopathology

J Am Soc Cytopathol. 2017 Nov-Dec;6(6):217-222. doi: 10.1016/j.jasc.2017.09.002. Epub 2017 Sep 14.

Authors

Edmund S Cibas¹, Syed Z Ali²

Affiliations

¹ Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts. Electronic address: ecibas@bwh.harvard.edu.
² Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, Maryland.

PMID: 31043290
DOI: 10.1016/j.jasc.2017.09.002

Abstract

The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) established a standardized, category-based reporting system for thyroid fine-needle aspiration (FNA) specimens. The 2017 revision reaffirms that every thyroid FNA report should begin with 1 of 6 diagnostic categories, the names of which remain unchanged since they were first introduced: (1) Nondiagnostic or Unsatisfactory; (2) Benign; (3) Atypia of Undetermined Significance (AUS) or Follicular Lesion of Undetermined Significance (FLUS); (4) Follicular Neoplasm or Suspicious for a Follicular Neoplasm; (5) Suspicious for Malignancy; and (6) Malignant. There is a choice of two different names for some of the categories: a laboratory should choose the one it prefers and use it exclusively for that category; synonymous terms (eg, AUS and FLUS) should not be used to denote 2 distinct interpretations. Each category has an implied cancer risk that ranges from 0% to 3% for the "Benign" category to virtually 100% for the "Malignant" category, and, in the 2017 revision, the malignancy risks have been updated based on new (post 2010) data. As a function of their risk associations, each category is linked to updated, evidence-based clinical management recommendations. The recent reclassification of some thyroid neoplasms as non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) has implications for the risk of malignancy, and this is accounted for with regard to diagnostic criteria and optional notes. Such notes can be useful in helping guide surgical management.

Keywords: Bethesda; Cytopathology; Fine-needle aspiration; Molecular testing; Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP); Terminology; Thyroid.