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Background: The calcifying fibroblastic granuloma (CFG) is a variant of epulis characterised histologically by calcified nodules and metaplastic bone formation and clinically by its pattern of frequent recurrence. Recent evidence suggests that calcified nodules and bone may form directly from non-haemopoetic pericytes in a variety of situations. This study aimed to test the hypothesis that metaplastic bone formation in CFG may be the result of a pericytic differentiation pathway.Methods: A series of 16 cases of CFG meeting the criteria of Lee were reviewed and stained using markers which aid the identification of pericyte (smooth muscle actin, von Willebrand's factor, monoclonal antibody 3G5) and osteoblast (AML-3) lineages.Results: The cells in mineralising areas of CFG resembled pericytes morphologically. Often, calcified nodules were observed within the vascular basement membrane and nodules frequently formed the nidus for reactive bone formation. The pericyte-like cells were positive for smooth muscle actin and AML-3 and were negative for von Willebrand's factor.Conclusions: These data provide circumstantial evidence for a pericytic lineage in CFG. [ABSTRACT FROM AUTHOR]

Basic fibroblast growth factor (bFGF) is thought to play an important role in wound healing. However, its histological localization, both in normal and pathological conditions in the oral mucosa, has not been well documented. We have studied the immunolocalization of bFGF in normal gingiva and gingival epulis specimens corresponding to different organizing stages. In normal gingiva, bFGF was detected in subpopulations of macrophages, mast cells and most endothelial cells in the lamina propria. Granulation tissue in epulides was histopathologically classified into six organizing stages. In stages 1 and 2, a small number of bFGF-positive macrophages was seen at the periphery of ulcer bases. In stages 3 and 4, histologically characterized by prominent capillary proliferation, large numbers of bFGF-positive macrophages and mast cells were located within granulation tissue. A positive reaction for bFGF was also found in some endothelial cells and in myxoedematous stroma that was rich in heparan sulfate proteoglycan. In stages 5 and 6, when fibrosis was accelerated, bFGF-positive macrophages and mast cells decreased in number and were localized only at the periphery of the fibrous tissue. These findings suggest that maximum amounts of bFGF are synthesized and released from some macrophages and mast cells into the extracellular matrix during neovascularization of granulation tissue. [ABSTRACT FROM AUTHOR]

Eight specimens each of the following groups were investigated: gingival pyogenic granuloma, fibrous epulis, calcifying fibrous epulis, peripheral giant cell granuloma, giant cell fibroma (four gingival, four non-gingival), denture-irritation hyperplasia and fibroepithelial polyp. These lesions have diverse histopathological appearances but the composition of their connective tissue is poorly defined. The elastic system consists of a complex mixture of glycoproteins that in normal oral mucosa form three differentially distributed fibre types; oxytalan, elaunin and elastic. The elastic system was investigated by Verhoeff's haematoxylin stain, aldehyde fuchsin staining and an anti-elastin monoclonal antibody. Elastin was identified in all fibroepithelial polyps and denture-irritation hyperplasias, but in none of the other lesions. In particular, this identified a distinct difference in the extracellular matrix between the giant cell fibroma and fibroepithelial polyp. Many of the epulides included only oxytalan fibres, but the presence of oxytalan fibres did not follow any pattern within either a single lesion group, or between different lesions. However, the presence of oxytalan fibres in the absence of elastin does not necessarily support a periodontal ligament origin for reactive epulides. [ABSTRACT FROM AUTHOR]

Focal reactive overgrowths of oral mucosa were investigated in the following groups: gingival pyogenic granuloma, fibrous epulis, calcifying fibrous epulis, peripheral giant cell granuloma, giant cell fibroma, fibroepithelial polyp and denture-related fibrous hyperplasia (n = 8 for each group). We hypothesised that immunoreactivity to tenascin-C, a functional protein associated with connective tissue organisation and cell migration, would be differentially distributed in individual lesions and between lesion groups. Staining patterns for giant cell fibromas and fibroepithelial polyps were similar to those reported for normal mucosa. By contrast, additional staining was observed in the other lesion groups, although immunoreactivity was variable and not specific to each lesion group. Strong immunoreactivity was observed around blood vessels lined with plump endothelial cells and in regions where keratinocytes were migrating over ulcerated surfaces. Interlacing collagenous fascicles could be either strongly or weakly immunoreactive, with either fibrillar or diffuse staining. Localised staining was observed around, but not within, areas of calcification. [ABSTRACT FROM AUTHOR]

Immunohistochemical detection of bone morphogenetic protein (BMP) in calcifying fibrous epulis was performed to elucidate the biological process of ossification and cemento-ossification. In a total 25 cases, 15 (60%) showed positive BMP staining in bone forming areas. Histopathological features of developing hard tissues were varied, consisting of structures such as woven bone and cemento-osseous formations. BMP immunostaining was limited to osteoblasts and fibrous connective tissue surrounding the bone matrix. BMP was concentrated in the periodontal fibres and in dense fibrous structures in the cemento-osseous masses. On the basis of histopathological and immunohistochemical features, the histogenesis of ossifying and cemento-ossifying processes appear to be of two possible origins; the excessive proliferation of periodontal ligament and a meta-plastic process occurring in the connective tissue fibres (non-periodontal in origin), with the former being more common. [ABSTRACT FROM AUTHOR]

The congenital gingival granular cell tumor (CGGT) or congenital epulis is a rare lesion of unknown origin found only in newborn infants. The tumor consists mainly of large eosinophilic granular cells arranged in solid nests that are separated by thin fibrovascular areas. In addition, there are some spindle-shaped cells and medium-sized polygonal cells (so-called interstitial cells) among the neoplastic granular cells. Three CGGTs were investigated with a panel of poly- and monoclonal antibodies, using immunoperoxidase methods on formalin fixed paraffin embedded sections. Neoplastic granular cells of these three cases show cytoplasmic staining for neuron-specific enolase (NSE) and vimentin. However, all other reactions were negative. Our results suggest that the lesion may be derived from uncommitted nerve-related mesenchymal cells. On the other hand, interstitial cells show strong S-100 protein-, cytokeratin-, vimentin-, and NSE-immunostainings, and these cells are consistent with neuroendocrine nature. The presence of a biphasic cell population with granular cells and interstitial cells must be considered the main immunohistochemical feature. [ABSTRACT FROM AUTHOR]

gggEighty-one cases of canine epulides are described clinically and histologically, 73 cases were diagnosed as inflammatory, fibrous hyperplasias of which 37% showed metaplastic bone formation and 22% demonstrated so-called plexiform epithelial hyperplasia which seems to have no human counterpart. There is no indication that metaplastic bone formation or plexiform epithelial hyperplasia influences the biologic behavior of the lesion. A distinction between these two histologic variants carries no prognostic significance. Six cases of epulides proved to be pyogenic granulomas and two were malignant tumors. It is stressed that the term epulis is non-specific giving no indication as to the true nature of the lesion. [ABSTRACT FROM AUTHOR]