Comparison of conventional cytology and SurePath in split thyroid fine needle aspiration materials

The aim of the present study was to compare the cytomorphological features and cytopathological diagnoses in thyroid aspiration materials prepared by SurePath® (SP) and conventional cytology (CC).

Fine needle aspiration (FNA) materials from 180 thyroid nodules were divided into two groups to prepare three conventional smears and one SP slide. Twenty-nine cytomorphological features of thyroid lesions were compared in the CC and SP slides. The Kappa coefficiency was determined for each. The cytopathological diagnosis of CC and SP were compared.

The feature with the lowest Kappa coefficient was the haemorrhagic background, whereas nuclear molding had the highest Kappa coefficient. The rates of the atypical and suspicious cytopathological diagnostic categories were decreased, whereas the rates of benign and malignant categories were increased in SP. When the cytopathological diagnoses of CC and SP were compared with the histopathological diagnoses of the 31 thyroidectomy materials, the results were similar.

The common problems seen in CC, such as an excessive number of slides, a haemorrhagic background and air drying artefact in the SP method were not encountered. Through these advantages, the rate of the indeterminate cytopathological diagnosis was low in SP. In addition to those advantages, the increased rates of non-diagnostic cases, the difficulty in evaluating the cytomorphologic features owing to tridimensional structures and the smaller size of the cells and the presence of tridimensional structures uninterpreted microscopically were the disadvantages of SP. The present results showed that SP could be used instead of CC in thyroid cytopathology.