Expression of receptor activator of NF-B ligand and osteoprotegerin in peripheral giant cell granulomas of the jaws

J Oral Pathol Med (2010) 39: 687-689Background: Peripheral giant cell granuloma is a tumor of the jaw characterized by the presence of multinucleated giant cells and mononuclear cells within a fibrous stroma. These lesions are considered to be of a reactive nature rather than neoplastic. Although peripheral giant cell granulomas is a well-described clinical entity, little is known on its pathogenesis. The aim of this study was to investigate the receptor activator of NF-B ligand (RANKL) and osteoprotegerin (OPG) expression and immunolocalization in giant cell granulomas.Methods: RANKL and OPG protein expression was evaluated in 22 peripheral giant cell granulomas samples, by means of immunohistochemistry. Staining was evaluated semi-quantitatively, according to the extent and intensity of the stain.Results: RANKL was expressed in all cases with a cytoplasmic staining pattern, whereas OPG expression was detected in 21 of the 22 cases examined. Active multinucleated giant cells exhibited intense immunoreactivity for both proteins.Conclusion: RANKL and OPG are expressed in peripheral giant cell granulomas of the jaw in a manner supporting the osteoclastic nature of giant cells whereas the possible osteoclastic lineage of stromal monocytes remains ambiguous.