Accuracy of FNAC in Thyroid Nodules in Comparison with Surgical Specimen: Qena Oncology Center Experience

Abstract

Background: Thyroid diseases are very common. Preoperative thyroid FNAC is now routine for most of thyroid surgery.

Objective: We aimed to compare preoperative FNAC of thyroid enlargement with postoperative histopathology to obtain a consensus  methodology as a straightforward technique for diagnosing and optimally managing thyroid disorders.

Patient and methods: A retrospective study that was conducted at Qena Oncology Center at Department of Surgery including all   patients underwent thyroid surgery during the period from January 2021 to June 2022. All FNAC were obtained under sonography  guiding. The data of age, gender, complaint, unilateral or bilateral, U/S TIRADS & nodularity, type of operation and the result of pathology  of FNAC and post-operative specimens were retrieved.

Results: The study included 98 cases of thyroid nodules (TN)  diagnosed clinically where 85 patients (86.7%) females and 13 patients (13.3%) males. The main complaint of these patients was neck  swelling in 65 patients (66.33%). FNAC results of 98 cases were 17 cases (17.4%) were malignant thyroid tumor (all of them were papillary)  and 81 cases (82.6%) were benign, hemorrhagic smears or suspicious lesions. After surgical excision, histopathology 73 cases (74.5%) were benign lesions and 25 cases (25.6%) were malignant thyroid lesions, 24 cases (24.6%) were papillary carcinoma variants and  only one case (1%) follicular carcinoma. The sensitivity of FNAC in determining malignant thyroid disease in our study is 68%. Specificity  was 100% as no cases were reported as false positive by FNAC for malignancy in our study. So, the accuracy of the FNAC in TN for  detecting cancer was 91.8% and the positive and negative predictive values were 100% and 90.1%, respectively.

Conclusion: Our study's  findings are consistent with the data already available in publications, showing that FNA cytology is a sensitive, specific, and accurate first  diagnostic test.