An alternative method for smear preparation of fine-needle aspiration cytology of cystic thyroid lesions: Evaluation of sample adequacy

Abstract

Background Cystic thyroid lesions represent one of the most common causes of unsatisfactory fine-needle aspiration sampling. Thus, it is important to access the maximum number of follicular cells from cystic fluid in order to reduce unsatisfactory rates. We compared the traditional method of smearing with an alternative one. Methods For each thyroid nodule, two smears were collected. Each smear was prepared using a distinct approach: either using the traditional technique or the alternative. Clinical data were taken from cytopathological request forms. The cytological aspects of the smears (eg, adequacy and number of cells) were observed during microscopy analysis. No cases were found to be suspicious for malignancy during ultrasound analysis (categories TR1 or TR2 according to ACR TI-RADS). Results Thirty-five cases were analyzed. For smears prepared using both the traditional and the alternative techniques, 20 and 4 cases, respectively, were unsatisfactory. In the 20 unsatisfactory traditional smear cases, 9 (45%) showed enough cells for diagnosis in cytospin and/or cell block samples; the four unsatisfactory alternative method cases showed the same. There was a statistical difference between the two methods of collecting a smear concerning sample adequacy (P< .001), but there was no statistical difference regarding the cellularity (P= .842). Conclusion In our data, the alternative method of using only one slide and the needle tip had higher rates of adequate sampling. Since it is cost effective and does not change the cytological analysis, this proposed alternative method can be useful in cases of cystic thyroid lesions.