Perspectives and limitations of the diagnosis of squamous cell carcinoma usingprobe-based confocal laser endomicroscopy

Confocal laser endomicroscopy (CLE) is an optical imaging technique that provides in vivo, microscopic images of the mucosa of the upper aerodigestive tract at 1000x magnification. We see the potential of this method in the "real-time" assessment of tumor extension at a cellular level for defining resection margins. We acquired CLE images during tumor resections and matched the acquired sequences with histology. Healthy mucosa showed epithelial cells of uniform size and shape, with clearly delineated intercellular spaces and regular vascular architecture in the form of intra-epithelial capillary loops. In contrast, images from the marginal area of squamous cell carcinoma showed disorganized tissue structure with variable cell morphology and atypical vascular patterns. Based on our findings, we established systematic grading criteria for the diagnosis of squamous cell carcinoma of the upper aerodigestive tract and demonstrated an overall accuracy of 88%, with substantial inter-rater reliability. Further validation of scoring criteria and optimization of image acquisition may bring CLE closer to application in clinical routine