Application of a Thin-layer Liquid-based Technique in Ultrasound-guided Fine Needle Aspiration of Thyroid

  Objective  To investigate the usefulness of the thin-layer liquid-based cytology in ultrasound-guided fine needle aspiration (UG-FNA) of thyroid gland lesions.

  Methods  From January 2008 to July 2008, 57 thyroid lesions from 57 patients aged from 18 to 78 in Peking Union Medical College Hospital were sampled by ultrasound-guided fine needle aspiration. The cytologic materials were prepared for both conventional and thin-layer liquid-based cytology by PRPSTAIN Processor (Tripath Imaging, BD, USA). All cytological diagnoses were compared with those confirmed by surgical pathology and clinical follow-up. The UG-FNA results were classified as benign, malignant, suspicious, or unsatisfactory. The various cytologic features on liquid-based cyto-logy and conventional preparation were compared.

  Results  Cytomorphologic features showed some differences between the two methods. Liquid-based cytology slides had a clear background and less or dense colloid. It demonstrated more cell shrinkage and showed increased disruption of the cytoplasm and numerous naked nuclei. Among the 57 thyroid lesions, surgical pathology and clinical follow-up confirmed that 6 were malignant and 51 were benign. The thin-layer technology showed that 48 (84.2%) were benign, 4 (7.0%) were malignant, and 5(8.8%)were unsatisfactory for interpretation. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 66.7%, 100%, 94.5%, 100%, and 96.2%, respectively, which were similar with conventional method.

  Conclusions  Liquid-based cytology technique has certain different cellular features when compared with conventional smears but with similar diagnostic accuracy. It is an accurate and reliable method for the preoperative cytological diagnosis of thyroid nodules.