Ex vivo microstructural investigations of oral lichen planus lesions by spectral domain optical coherence tomography.

The aim of the work is to evaluate the Optical Coherence Tomography (OCT) capabilities in identifying the microstructural pattern of reticular Oral Lichen Planus (OLP) and compare it with the histopathological findings, to identify a common interpretation key and validate OCT as a diagnostic tool for this autoimmune inflammatory pathology. Eight patients were recruited (aged between 44 and 71 years). The anatomical sites chosen is the buccal mucosa, since it is typical of lichen lesions to be analysed. We took into consideration typical white signs of OLP: reticular and plaque lesions. Comparison between OCT scans and histological slides were carried out. Results show a strong correlation between OCT and histopathological evaluations. Hyperkeratosis occurs as a superficial hyperreflective zone. The lamina propria loses its hyper-reflective characteristic. This is probably due to the presence of the inflammatory infiltrate, which causes a decrease in signal strength. For the basement membrane, difficulties were encountered in interpreting it. This study shows that it is possible to identify clear differences between pathological tissue and healthy counterpart in OCT, both in epithelial and connective tissues. In addition, we observed a concordance in epithelial measurements between OCT image and histological image. These observations indicate promising potentials and need to be confirmed by further studies, in order to compare the results and arrive to an objective pattern of OLP, framing the possible role of OCT as a non-invasive diagnostic tool.