Cytomorphological Categorization of Thyroid Lesions according to The Bethesda System for Reporting Thyroid Cytology and Correlation with their Histological Outcome: An Indian Oncology Centre Experience

Objective: The objective of this study was to report the experience of an Indian premiere tertiary care oncology center in reporting fine needle aspiration cytology of thyroid lesions according to the Bethesda system of reporting thyroid cytopathology (TBSRTC) given by National Cancer Institute (NCI). These were then correlated with their histopathological outcome, analyzing the level of specificity and sensitivity of the procedure. Material and Methods: Aspiration cytology of thyroid lesions, presented during a 5.5-year duration, was reported retrospectively and prospectively, according TBSRTC, and correlated with their histopathologic diagnosis. Results: A total of 431 patients were evaluated comprising 289 females and 142 males, with a median age of 52 years. Among the cytological categories 80 (18.6%) were non-diagnostic (ND), 131 (30.2%) benign, 45 (10.4%) follicular lesion of undetermined significance (FLUS), 27 (6.3%) follicular neoplasm, 33 (7.9%) suspicious for malignancy (SM), and 115 (26.7%) malignant. Histopathology reports were available in 142 of these cases. Final malignant diagnosis was reported in 11 of 14 ND (78.6%), 5 of 18 benign cases (27.7%); 9 of 17 FLUS (52.9%), 7 of 13 FLUS (53.89%), 19 of 20 SM (95%), and 58 of 60 malignant cases (96.7%). The procedure had sensitivity of 94.4%, specificity of 61.9%, positive predictive value of 90.3% and negative predictive value of 72.22%. Conclusion: TBSRTC provides uniform categorization of thyroid cytology, which also helps in further management. This valid system has helped to streamline the reporting terminologies as well as the clinical management.