Publication:

Diagnostic accuracy of ultrasonography and fine needle aspiration cytology in thyroid swellings: correlation with final histopathology

Background Thyroid nodules are common in clinical practice and accurate preoperative differentiation between benign and malignant thyroid nodules is essential to avoid unnecessary surgery while ensuring timely management of malignancy. Ultrasonography (USG) and fine needle aspiration cytology (FNAC) are commonly used diagnostic tools, but their accuracy varies across clinical settings. To evaluate the diagnostic accuracy of USG and FNAC in thyroid swellings by comparing preoperative findings with final histopathological examination.

Methods This retrospective observational study included 190 patients with thyroid swellings who underwent thyroidectomy at a tertiary care centre between January 2015 and May 2022. Preoperative USG and FNAC findings were correlated with postoperative histopathology. Sensitivity, specificity and diagnostic accuracy of each modality were calculated.

Results Of the 190 patients screened, 187 with complete histopathological data were included in the final correlation analysis. Histopathology confirmed malignancy in 75 cases (40.1%) and benign disease in 112 cases (59.9%). When correlated with final histopathology, FNAC demonstrated sensitivity of 77.3%, specificity of 87.5% and diagnostic accuracy of 83.4% as compared to USG with sensitivity of 82.7%, specificity of 63.4% and diagnostic accuracy of 71.1%. Sonographic features such as taller-than-wide shape, solid composition and punctate echogenic foci showed significant association with malignancy (p<0.01).

Conclusions USG and FNAC are valuable complementary tools in evaluating thyroid swellings. FNAC is a highly specific and accurate diagnostic modality for thyroid swellings, while USG serves as an effective screening and risk stratification tool. Their combined use significantly improves diagnostic accuracy and helps reduce unnecessary thyroid surgery, although histopathology remains the definitive diagnostic modality.