Comparative Study of Cell Findings by Conventional Smear and Liquid-Based Cytology for Oral Exfoliative Cytology

Background: Liquid-based cytology (LBC) is a method of manufacturing cyto-diagnostic specimens. Improved accuracy is expected from standardizing specimen production and use of this method is rapidly spreading in oral cytology. On the other hand, LBC reportedly requires training to show peculiar cell findings compared to those of conventional smear cytology (CVC). Few studies have compared detailed cell findings for oral CVC and LBC. Objectives: The aim of this study was to compare cytological findings between CVC and LBC using cytomorphological image analysis. Materials and Methods: Cytological specimens were collected from 20 patients (negative for squamous neoplasia in 10, dysplasia in 5, squamous cell carcinoma in 5) and 5 controls of the tongue between January 2017 and December 2018. Two different preparation techniques were investigated cytomorphologically for CVC and LBC (BD CytorichTM). Results: LBC showed significantly higher cell numbers than CVC for all lesions. LBC-to-CVC ratio ranged from 9.52 (hyperkeratosis) to 1.87 (deep cells in oral squamous cell carcinoma (OSCC)). Nuclear area of normal, hyperkeratosis, and inflammation were significantly higher in LBC than those of CVC. Hyperchromasia was significantly more frequent with CVC than with LBC for hyperkeratosis, inflammation, dysplasia and OSCC. There was no significant difference in circularity between CVC and LBC among all lesions. Conclusion: Only one cytomorphological disadvantage was seen with LBC, in the form of decreased hyperchromasia. Further clarification of the advantages and disadvantages of LBC is needed, including management of precision and screening practices.