Liquid-based cytology versus conventional cytology in fine-needle aspiration cytology of thyroid, salivary gland, and lymph node swellings: a comparative study

Purpose To compare the cytomorphologic features of liquid-based cytology (LBC) and conventional preparation (CP) smears in fine-needle aspiration of thyroid, lymph node, and salivary glands. Patients and methods The study included 110 patients experiencing thyroid, salivary gland, and lymph node swellings, who presented to the Surgical Oncology Outpatient Clinic and referred to Cytology Unit of the Pathology Department of the National Cancer Institute, Cairo University, for fine-needle aspiration cytology, from the period January 2017 till July 2018. For each fine-needle aspiration cytology, three passes were performed: the first two were for conventional cytology, and the third one for LBC, where a semiautomated SurePath technique was used. The comparison between both techniques was done using Wilcoxon signed rank test, regarding the cellularity, cell architecture, monolayering, nuclear details, cytoplasmic details, informative background, and bloody background. Results CP was significantly better regarding the cellularity, cellular architecture, and informative background of thyroid lesions, whereas LBC was better when the absence of bloody background was considered. On the contrary, no significant difference was found between both preparations regarding monolayer formation and nuclear and cytoplasmic details. Conclusion CP is superior to LBC in preservation of cellular pattern, gives better cellular yield, eliminates hemorrhagic background, and maintains the stroma and background, which are important for diagnosis. As such stroma is lacking in LBC, it should be interpreted with support of CP in certain lesions.