PHENOTYPIC CHARACTERIZATION OF STELLATE AND GIANT-CELLS IN GIANT-CELLFIBROMA BY IMMUNOCYTOCHEMISTRY

The origin of the stromal, stellate and multinucleate cells in oral gi ant cell fibroma is unclear. Sixteen giant cell fibromas were stained immunocytochemically for keratin (MNF 116), vimentin, S-100 protein, n eurofilaments, glial fibrillary acidic protein, oc-smooth muscle actin , desmin, CD31 (PECAM-1), CD68, Factor XIIIa and prolyl 4-hydroxylase (5B5). In all cases positive staining was found with vimentin and prol yl 4-hydroxylase, indicating a functional fibroblast phenotype. Reacti vity for Factor XIIIa was seen in two cases and in only one was a smal l number of giant cells stained, suggesting that the majority of oral giant cell fibromas are unrelated to the histologically similar fibrou s papule of the nose or facial angiofibroma.