Assessing Diagnostic Concordance: A Retrospective Review of Preoperative Ultrasound and FNAC Against Final Histopathology

Abstract

Background-

Accurate preoperative diagnosis of thyroid nodules is essential to guide appropriate management and avoid unnecessary surgery. Ultrasound (USG) and fine-needle aspiration cytology (FNAC) are widely used diagnostic tools; however, their concordance with histopathology varies.

Aim:

To evaluate the diagnostic concordance and sensitivity of USG and FNAC compared with final histopathology in thyroid malignancies.

Methods:

This retrospective study included 15 patients with thyroid swelling who underwent USG, FNAC, and subsequent thyroid surgery between November 2022 and September 2024. Preoperative findings were compared with histopathological examination (HPE). Sensitivity and positive predictive value (PPV) were calculated.

Results:

All 15 cases were histopathologically confirmed malignancies. USG detected 6 true positives and 9 false negatives (sensitivity: 40%, PPV: 100%). FNAC detected 9 true positives and 6 false negatives (sensitivity: 60%, PPV: 100%). Papillary carcinoma was the most common malignancy (73.3%), followed by follicular (13.3%) and medullary carcinoma (13.3%).

Conclusion:

FNAC demonstrated higher sensitivity than USG, but neither modality alone was sufficient for detecting all malignant cases. A combined diagnostic approach improves accuracy and clinical decision-making.