The impact of rapid on-site assessment of thyroid cytology on final histopathologic diagnosis and cytologic adequacy rates

ABSTRACT The İmpact of Rapid On-Site Assessment of Thyroid Cytology on Final Histopathologic Diagnosis and Cytologic Adequacy Rates Thyroid fine needle aspiration cytology (FNAC) is a fast, safe and economical method for the evaluation of thyroid nodules. Although definitive diagnosis is not always possible, FNAC contributes to the further patient management and reduce unnecessary operation. The major problem in thyroid FNAC is the inability to aspirate adequate follicular epithelial cells. Rapid on-site assessment of fine needle aspiration is an effective method for solving this problem. In our study, we aimed to evaluate whether rapid on-site evaluation of thyroid FNA with under USG guidance or by palpation only was effective at improving adequacy rates and histological diagnosis accuracy rate. In this study, in the Department of Internal Medicine or General Surgery Department of Kafkas University Medical Faculty Health Research and Application Center were applied 443 (369 women, 74 men) patients who had nodular thyroid disease and performed FNAC, between 2012 and 2015 years, were included. On-site adequacy assessment of the aspirated material was performed in 247 cases, whereas 196 cases were performed without onsite evaluation. 49 of the 247 patients and 29 of the 196 patient undergo operation. FNAC cytological assessments were performed according to Bethesda Classification. Cytological and histopathological diagnosis were compared with the rates of sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy. 38 of the 247 patients (15,4%) evaluated with rapid onsite adequacy assessment and 79 of the 196 patients (40,3%) without onsite evaluation had non-diagnostic cytology result. The difference between these two groups was statistically significant. Within the onsite group; 146 cases (59,1%) benign, 46 cases (18,6%) atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS), 7 cases (2,8%) follicular neoplasm or suspicious for a follicular neoplasm (FN/SFN), 9 cases (3,6%) suspicious for malignancy, 1 case (0,4%) malignant were reported. Without the onsite group; 86 cases (43,9%) benign, 15 cases (7,7%) AUS/FLUS, 2 cases (1,0%) FN/SFN, 13 cases (6,6%) suspicious for malignancy, 1 case (0,5%) malignant result were obtained. As a result of comparing cytologic and histopathologic diagnoses within the onsite group; sensitivity was 30,7%, specificity was 75%, positive predictive value was 50%, negative predictive value was 57,1%, diagnostic accuracy was 55,1%; without the onsite group sensitivity was 50%, specificity was 69,2%, positive predictive value was 42,8%, negative predictive value was 75%, diagnostic accuracy was 63,1%. Rapid on-site adequate evaluation does not contribute to the diagnostic accuracy rate even if it decrease the nondiagnostic rate. In our study, sensitivity, specificity, and diagnostic accuracy rates are slightly lower than in other studies in the literature. The reason is that our study, the papillary microcarcinoma focus can not sampled with FNAC performed by palpation alone, in the cytological as follicular epithelial cells sometimes show reactive changes (nuclear clearing, enlargement, overlapping) is due to misinterpretation as suspicious for malignancy.