Evaluation of the Italian Cytological Reporting System and Comparison with Histopathology with Respect to Indeterminate Thyroid Lesions

Abstract

Introduction: The British system (RCPath-Thy1-5), The Bethesda System for Reporting Thyroid Cyto-Pathology (BSRTC) and The Italian Society of Anatomic Pathology and Cytology (SIAPEC) classification are the most practised thyroid reporting systems with high discriminative factor in classifying thyroid lesions on Fine Needle Aspiration Cytology (FNAC). Surprisingly, none of these classification systems are reliable, when the question is about ‘indeterminate for malignancy’ category. Aim: To find out a better cytological reporting system between Bethesda and Italian classification with respect to indeterminate lesions of thyroid. Materials and Methods: A cross-sectional retrospective study was undertaken in department of Cyto pathology at SDM College of medical sciences and hospital, Dharwad from year January 2015 to January 2018. Thyroid FNAC cases were collected from departmental archives. Among these cases, all FNAC slides for which thyroid surgery were done were reviewed by two cytopathologists and reporting was done using SIAPEC reporting system and BSRTC system. Among those cases (N=33), only indeterminate lesions were selected for the study. Fourteen cases were reported under TIR-3A and 19 cases were reported under TIR-3B. Histological outcomes and cyto-histopathological comparision was done using Chi-Square test. Risk Of Malignancy (ROM), sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) were determined. Results: ROM for TIR-3A lesions is 35.7% and for TIR-3B lesions is 58.89%. ROM for Atypia of Undetermined Significance/ Follicular Lesion of Undetermined Significance (AUS/FLUS) lesions is 71.4% and Follicular Neoplasm (FN)/Suspicious for FN category (FN/SFN) lesions are 42.3%. The study revealed very high sensitivity and specificity under Italian system when compared to Bethesda system in identifying malignant outcomes. ROM in Italian sub-classification was more than the anticipated levels. Conclusion: Current study concludes that SIAPEC reporting system is more satisfactory than BSRTC system while evaluating the indeterminate nodules for malignant outcomes. Our results indicate that cases classified solely on architectural atypia have almost 50% lower ROM when compared with cases with cytological atypia.

Keywords

• bethesda system
• cytology
• italian society of anatomic pathology and cytology
• thyroid indeterminate lesions