Diagnostic Accuracy of Fine-Needle Aspiration Cytology (FNAC) in Thyroid Nodule Excision Cases

Abstract

Introduction: Fine needle aspiration cytology (FNAC) for thyroid nodules has a high diagnostic accuracy, according to several studies worldwide. Patients who experienced preoperative FNAC had more optimal surgical treatment than others who did not perform FNAC. Therefore, achieving an accurate FNAC procedure appears to be an important tool for the proper management of thyroid nodules. We aimed to study the accuracy and challenges of the thyroid FNAC diagnostic tool in the Al-Baha region, Kingdom of Saudi Arabia.

Methods: The study involves 52 patients with thyroid nodules who underwent preoperative FNAC and postoperative histopathology with the same surgery and pathology team at Al-Baha region in 2022-2023.

Results and conclusion: The mean age of the included patients was 47.7 years, with a female predominance. The diagnostic accuracy was 90%, and the main cause of inaccurate diagnosis was processing challenges, where the majority of cases were taken on the palpation-only technique, a few cases were ultrasound-guided, and the only technique used in the laboratory was conventional smears. The applied interrater reliability Cohen kappa coefficient (κ) for the clinical-histopathological agreement was "moderate agreement". We recommend using and evaluating more cytological techniques in addition to the currently used conventional smears in pathology laboratories to enhance the efficacy of the FNAC diagnosis of thyroid lesions.

Keywords: bethesda system; ent clinic; fnac; thyroid nodule; thyroidectomy.

Figure 1. Representative ultrasound images

Ultrasound images of the right and the left lobe of the thyroid showing multiple hypoechoic nodules that were proven by histopathology as nodular goiter negative for malignancy.

Figure 2. Histopathology images

A case of follicular thyroid nodule; A) Preoperative FNAC showing benign features, Category 2. B) Postoperative histopathology showing follicular lesion with capsular invasion finally diagnosed as follicular carcinoma (H&E, 40x).