Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, 98122 Messina, Italy
Francesca Mazzeo
Department of Human Pathology of the Adulthood and Developing Age “Gaetano Barresi”, Section of Pathology, University of Messina, 98124 Messina, Italy
Gaetano Basilio Militi
Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, Human Pathology Section, University of Palermo, 90127 Palermo, Italy
Giovanni Tuccari
Department of Human Pathology of the Adulthood and Developing Age “Gaetano Barresi”, Section of Pathology, University of Messina, 98124 Messina, Italy
Antonio Ieni
Department of Human Pathology of the Adulthood and Developing Age “Gaetano Barresi”, Section of Pathology, University of Messina, 98124 Messina, Italy
Esther Diana Rossi
Division of Anatomic Pathology and Histology, Catholic University, Foundation “Agostino Gemelli” University Hospital IRCCS, 00168 Rome, Italy
Guido Fadda
Department of Human Pathology of the Adulthood and Developing Age “Gaetano Barresi”, Section of Pathology, University of Messina, 98124 Messina, Italy
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.
