A Cell Pattern Approach for Interpretation of Fine Needle Aspiration Cytology of Thyroid Lesions Using the Bethesda System: A Tertiary Care Centre Study With Literature

Abstract

INTRODUCTION:Fine needle aspiration of thyroid lesions has proven to be an important, simple, safe, cost effective and accurate method for diagnosing the various thyroid lesions. Multiple organizations have proposed diagnostic guidelines for reporting thyroid cytology. National Cancer Institute (NCI) organized the NCI Thyroid Fine Needle Aspiration State of the Science conference in 2007 and proposed the Bethesda System for reporting Thyroid Cytopathology (TBSRTC). The aim of the study is to highlight the application of new nomenclature which can improve inter-laboratory agreement thus leading to more consistent management approach. MATERIALS AND METHODS:The present study was done on 91 random FNAC cases of thyroid lesions in Pathology Department, SGRDIMSAR. The cases were classified according to 6 levels of TBSRTC which are DC-I: Non diagnostic, DC-II: Benign, DC-III: atypia/follicular lesion of undetermined significance (AUS/FLUS), DC-IV: Follicular neoplasm/suspicion for a follicular neoplasm (FN/SFN), DC-V: suspicious for malignancy and DC-VI: Malignant RESULTS: In the present study females outnumbered males with the ratio of 5:1. The age group varied from 13-80 years with maximum number of cases in 3 rd and 4 th decade. Maximum numbers of the cases (48.5%) were benign followed by FN/SFN and malignant category constituting 20.8% and 12.2% respectively. 8.7% were classified under AUS/FLUS category, 6.5% as non-diagnostic and 3.3% as suspicious of malignancy. CONCLUSION: The management of thyroid lesions has been complicated by the lack of universal terminology. TBSTRC is an effective thyroid FNA classification to guide clinical management of patients with thyroid nodules. Its implementation should be encouraged in our country because of its easy understandability and reproducibility. KEYWORDS: Thyroid, Fine needle aspiration, FNA, Bethesda classification. INTRODUCTION:Fine needle aspiration (FNA) of thyroid gland is a widely accepted, simple, safe, cost-effective and accurate method for the evaluation of thyroid lesions. 1 Clinical evaluation, imaging including ultrasound and FNA are mainstay for evaluation of thyroid lesions patients. Among all, highest rate of detection of thyroid neoplasm arising in solitary nodule is achieved by cytological studies thus forming FNAC the most sensitive and specific test. 2 So FNAC provides information that guides the management of the patients with thyroid nodules by identifying the patients who require the surgical intervention. 3 Various cyto morphological features including predominant cell pattern, cell morphology, background and marginal vacuoles are taken into account for diagnosing various lesions. 4 The clinical management of lesions has been complicated by the lack of universal terminology.