Enhanced podoplanin expression in chronic maxillary sinusitis.

Podoplanin expression has been reported in oral squamous epithelium, myoepithelia of the salivary glands, and odontogenic lesions, and has been linked with inflammatory and neoplastic conditions. We hypothesized that inflamed respiratory mucosa of the maxillary sinus also express podoplanin, especially in cases with odontogenic sinusitis. We retrospectively investigated podoplanin expression in biopsies from maxillary sinus with inflammatory changes. Cases with chronic rhinosinusitis with polyp formation (n=5), chronic rhinosinusitis without polyps (n=5), chronic rhinosinusitis with eosinophilia (n=5), and odontogenic chronic rhinosinusitis (n=5) were investigated immunohistochemically using an established antibody for podoplanin (D2-40). Respiratory epithelium in chronic maxillary sinusitis with polyp formation did not exhibit enhanced podoplanin expression. However, D2-40 positivity was detected in the basal cells in all cases with chronic sinusitis associated with inflammatory infiltrations as well as in the parabasal epithelial layer in chronic sinusitis without polyp formation. We observed podoplanin expression in non-neoplastic maxillary sinus epithelium exhibiting inflammatory changes. We suggest that podoplanin is involved in the pathogenesis of chronic rhinosinusitis, particularly in the intraepithelial migration of inflammatory infiltrates.