Value of Combined Cytomorphological Parameters in Improving Diagnostic Accuracy of Papillary Thyroid Carcinoma on Cytology - The Five Dependable Features

BACKGROUND: Fine-needle aspiration cytology remains the preliminary test for diagnosing papillary thyroid carcinoma (PTC). Numerous features are established to arrive at the diagnosis. However, few cases pose a challenge to correctly diagnose PTC. Our study aims to elicit the combination of features to aid in the diagnosis of such cases. MATERIALS AND METHODS: Cytology smears of histologically proven cases of PTC and benign diagnoses were included as case (n = 36) and control group (n = 38), respectively. Features including papillae with cores, 3-D caps, nuclear grooves (NG), intranuclear cytoplasmic inclusions (INCI), giant cells, macrophages, cellular swirls, psammoma bodies, pale chromatin, nuclear overlapping, nuclear enlargement, and metaplastic cells were assessed. Statistic tests including Independent t test/Mann–Whitney Test and Chi-Square test/Fisher's Exact test were used. Receiver operating characteristic curve was used to assess the cut-off point of many cytological features to predict PTC. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of cytological features was calculated to predict PTC. RESULTS: Presence of five or more cytological features (papillae with cores, cellular swirls, NG, INCI, and psammoma bodies) together could diagnose PTC (PPV) in 78.95% of the cases, with a NPV of 83.33%. Diagnostic accuracy of these five features combined was 81.08%. Papillae with cores and nuclear grooving were the most sensitive cytological features, whereas INCI followed by cellular swirls and NG were the most specific features. CONCLUSION: Relying on a combination of the most sensitive and specific features rather than any one cytological feature can help reduce the misdiagnoses in PTC.