A correlative study of solitary thyroid nodules using the bethesda system for reporting thyroid cytopathology

Fine needle aspiration cytology (FNAC) is a useful diagnostic modality in the evaluation of solitary thyroid nodules (STN). It can differentiate between benign and malignant lesions in most cases.

This study was undertaken to determine the utility and diagnostic accuracy of FNAC in the evaluation of STN.

In this retrospective study, a total number of 483 thyroid FNACs were retrieved, out of which 209 cases of STN were chosen for this study. The Bethesda system for reporting thyroid cytopathology (TBSRTC) was used for analysis. Their FNACs diagnoses were compared with histopathological diagnoses.

Among 209 FNACs, 88 (42.1%) had non-neoplastic lesions, 6 (2.9%) had atypia of undetermined significance/follicular lesions of undetermined significance (AUS/FLUS), 52 (24.9%) had follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN), 33 (15.8%) were suspicious for malignancy and 18 (8.6%) had malignant cytology. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of FNAC in STN cases were 94.4%, 97.6%, 95.8%, 98.1% and 93.2% respectively.

Our study concluded that FNAC reporting using TBSRTC highly correlated with the histopathological diagnosis and our results were comparable with published data. The FNAC diagnosis helps in triaging patients with STN and identifies those who require surgical intervention. It is a simple, convenient, cost effective, sensitive, specific, safe and accurate initial diagnostic method for the preoperative evaluation of STN.