Keratin 17-positive Civatte bodies in oral lichen planus-distribution variety, diagnostic significance and histopathogenesis.

Although emergence of keratin 17 (K17) and reciprocal loss of K13 are immunohistochemical hallmarks for oral mucosal malignancy, we report here findings of K17-positive (+) speckles, possibly equivalent to Civatte bodies, in benign oral lichen planus. Sixty-two biopsy samples from oral lichen planus cases were subjected to immunohistochemical examinations to analyze the distribution as well as histopathogenesis of Civatte bodies. K17 was irregularly positive among oral lichen planus-affected epithelial cells, and K17-positive (+) filamentous structures were irregularly distributed within the cytoplasm in confocal images.