Liquid-based cytology in oral cavity squamous cell cancer

Purpose of review Oral exfoliative cytology is a practical tool for early diagnosis of squamous cell carcinoma (OSCC) and potentially malignant lesion (OPML), but is not yet extensively used. A literature review evaluated conventional and liquid-based oral diagnostic cytology efficacy and efficiency. 'Special' techniques like liquid-based cytology, computer-assisted cytology, Oral CDx, DNA ploidy, immunocytochemistry, molecular analyses and microhistology were reviewed. Recent findings Cytology was useful when diagnosing OSCC and OPML. Oral CDx may assess dysplastic changes in clinically suspicious (class I) lesions, with doubtful efficacy in apparently innocuous (class II) lesions. Flow and/or image cytometry and immunocytochemistry can identify markers for the prediction of evolution of the OPML to OSCC. Molecular biology can detect the minimal residual clonal population of cancer cells in field cancerization and oral mucosa surgical margins. Microhistology is a reliable first level test in class II lesions for selected cases requiring surgical biopsy. Summary Conventional cytology helps in OSCC and OPML screening; liquid-based cytology gives better results, enhancing both sensitivity and specificity, and provides material for further investigation. Sampling with the 'curette technique' permits collection of 'accidental' tissue fragments used as microbiopsies and proved a useful first-level test for the management of class II OPML.