Diagnostic Accuracy of Fine Needle Aspiration Cytology (FNAC) in Diagnosis of Solitary Thyroid Nodules Taking Histopathology as Gold Standard

Abstract

Background: Solitary thyroid nodules (STNs) often present in the medical field of otorhinolaryngology. The key to appropriate management is to establish a difference between benign and malignant nodules. FNAC is a first-line test, which is minimally invasive and cost-effective but its accuracy may vary, and histopathology should be compared with it. 

Purpose: To assess the diagnosis accuracy of FNAC of solitary thyroid nodule, based on the gold standard of histopathology. 

Methods: The study was a cross-sectional study conducted in the Department of ENT, Postgraduate Medical Institute (PGMI) of Shaikh Zayed Hospital, Lahore, in 5 December 2021 and 5 June 2022. 286 patients without any secondary thyroid nodules were recruited. They all went through FNAC and underwent surgery and histopathology of the specimen. FNAC findings were also compared with histology to determine sensitivity, specificity, PPV, NPV, and accuracy in general. 

Results: Out of the 286 respondents, 152 (53.1%) were between the ages of 12-40 and 134 (46.9) were between the ages of 41-80; mean age was 39.3 +/-.105 years. Men comprised 41.6% (119) and women 58.4% (167). FNAC was found to give an accuracy of 87.4% sensitivity of 86.1, specificity of 90.6 and PPV of 87.4. 

Conclusion: FNAC is a sensitive, specific and a true method of assessment of solitary thyroid nodules. It also aptly distinguishes between benign and malignant lesions providing proper surgical management and minimizing unnecessary surgeries.