Giant cell fibroma of the tongue: report of a case showing unique S-100 protein and HLA-DR immunolocalization with literature review

Abstract

We report a case of an 81-year-old female patient presenting a dome-shaped swelling at the tip of the tongue, pathologically diagnosed as giant cell fibroma. Histologically, the fibrous lesion contained abundant characteristic stellate giant cells (mono-, bi-, and multinucleate), the localization and morphology of which were consistent with that reported previously. The immunohistochemical profile of stellate giant cells was also generally consistent with previous reports, suggesting that such cells would chiefly be of the fibroblastic lineage. Our case was unique because the stellate giant cells were often in close proximity with human leukocyte antigen DR (HLA-DR)-positive spindle/dendritic cells and rarely showed S-100 protein positivity. These findings suggest that a minor subset of stellate giant cells could be monocytemacrophage lineage, although the majority was thought to represent fibroblastic lineage.