A Cytologic study of Thyroid lesions utilizing the Bethesda System of Reporting with Histopathologic Correlation

Background: Thyroid nodules, affecting 5-10% globally, pose a diagnostic challenge in distinguishing between benign and malignant lesions. Fine-needle aspiration cytology [FNAC], a key diagnostic tool, is guided by the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). Despite widespread adoption, challenges persist in accurately predicting thyroid lesions solely through cytology. Histopathologic examination remains the gold standard, and up to 20-30% of initially indeterminate nodules are later found to be malignant yet FNAC of the thyroid is the first line procedure that is widely used all over the world in the diagnosis of thyroid lesions. Aims: 1. To study the cytomorphology of various thyroid lesions utilising The Bethesda System of reporting thereby elucidating its utility. 2. Cytohistopathologic correlation; thereby analyzing the cause of diagnostic errors with an eventual aim to improve diagnostic accuracy. Methods: This retrospective study, conducted at Vikram Hospital, Mandya, spanned four years from August 2011 to May 2015. The study encompassed 205 patients who underwent fine-needle aspiration (FNA) of thyroid nodules, either sonographic guided or non-guided. Experienced cytopathologists, going through the clinical information, reviewed slides utilising the Bethesda System categories. Histopathologic slides were reviewed too and diagnoses were correlated with cytology. Descriptive statistics characterized Bethesda System categories and histopathologic outcomes. Concordance rates were calculated, and SPSS version 18.0 was used for statistical analyses (p < 0.001 considered significant). Results: In this study encompassing 205 patients, in the age group of 14-61 years,12.6% were males and 87.3% were females, with the majority (72.7%) aged 20-40 years. Cytologic evaluation categorized 87.8% as benign, predominant lesions being nodular goitre (56.1%) and colloid goitre (38.8%). Follicular neoplasms [3.9%] and Papillary carcinoma [3.9%] showed equal prevalence Follow-up histopathology for 143 cases showed high concordance between cytologic and histopathologic diagnoses, with sensitivity (95.00%) and specificity (97.56%) indicating the reliability of cytology in identifying thyroid lesions. The overall accuracy of cytologic evaluation was commendable at 97.20%. Conclusion: In conclusion, our study contributes valuable insights into the diagnostic accuracy of thyroid cytology, emphasizing its role in stratifying thyroid lesions based on the Bethesda System; being a very useful, uniform and standardized system for reporting thyroid cytopathology. The high concordance rates, along with robust sensitivity and specificity values, highlight the reliability of cytologic assessments.