Reporting Thyroid Cytology in a Globalized World

Abstract

The Italian SIAPEC-AIT 2014 classification, the 2017 Bethesda System for Reporting Thyroid Cytology (TBSRTC), the 2016 UK Royal College of Pathologists (RCPath) thyroid reporting system, and the 2019 Japanese reporting system for thyroid aspiration cytology (JRSTAC2019) represent the most widely used reporting systems among clinicians and pathologists for the purpose of cytologically diagnosing, estimating the potential risk of malignancy (ROM), and defining the most appropriate treatment for a patient with a thyroid nodule. Although all the systems use overlapping diagnostic categories and morphologic criteria, they differ on the basis of the criteria for inclusion in the cytologic categories, which may, in turn, affect the ROM of a given category and the clinical management of the patient, particularly with regard to the “indeterminate” categories. The aim of this review is to analyze the main differences that emerge between the systems and to propose possible solutions for a comprehensive reporting system that integrates and harmonizes all the criteria of the Italian classification and the Bethesda system, also taking into account the impact that the new tumor entity NIFTP (non-invasive follicular tumor with papillary-like nuclear features) that has, in many instances, replaced the non-invasive form of the follicular variant of papillary carcinoma, has had on the modification of malignancy risks.

Effect of the COVID-19 pandemic on surgery for indeterminate thyroid nodules (THYCOVID): a retrospective, international, multicentre, cross-sectional study

“…For the purpose of this study, cytological findings were reported according to the Bethesda system, as widely accepted in the literature. 14 , 15 The nodules classified as Bethesda class III or Bethesda class IV on FNAC were defined as indeterminate thyroid nodules.…”

Unveiling Variations: A Comprehensive Comparison of Five Globally Used Thyroid Cytology Reporting Systems With Histopathological Correlation

“…The term "atypia" encompasses both architectural and cytological atypia. Architectural atypia includes patterns such as papillae and microfollicles, while cytological atypia includes anisonucleosis, irregular nuclear membranes, chromatin texture, and prominent nucleoli [ 12 ]. The lack of standardized definitions contributes to interobserver variability in the atypia of undermined significance category, manifesting in divergent criteria among the reporting systems.…”