Ultrastructural aspects of connective tissue in hereditary gingival fibromatosis

Ultrastructural evaluation of gingival connective tissue in hereditary gingival fibromatosis

OBJECTIVE

To describe the ultrastructural features of hereditary gingival fibromatosis (HGF) in affected family members and compare microscopic findings with normal gingival (NG) tissue.

STUDY DESIGN

Gingival tissue samples from nine patients with HGF from five unrelated families were evaluated by transmission electron microscopy. Nine NG tissue samples were used for comparison.

RESULTS

Areas containing collagen fibrils forming loops and folds were observed in both groups, whereas oxytalan fibers were frequently identified in the HGF group. The diameter of collagen fibrils and the interfibrillar space among them were more uniform in the NG group than in the HGF group. Fibroblasts were the most common cells found in both the HGF and NG groups and exhibited enlarged, rough endoplasmic reticulum, mitochondria with well-preserved crests, conspicuous nucleoli, and euchromatic chromatin. Other cells, such as mast cells, plasma cells, and macrophages, were also observed.

CONCLUSIONS

HGF tissues had ultrastructural characteristics that were very similar to those of NG tissues. Oxytalan fibers were observed more frequently in the HGF samples than in the NG samples. Other studies of HGF in patients from different families should be performed to better understand the pathogenesis of this hereditary condition.

Hereditary gingival fibromatosis: clinical and ultrastructural features of a new family

Objective: This article describes the diagnosis, clinical and microscopic (histopathology and ultrastructural) features and treatment of a new family with hereditary gingival fibromatosis (HGF) and highlights the importance of this genetic condition. Study Design: To characterize the pattern of inheritance and the clinical features, members of a new family with HGF were examined. The pedigree was reliably constructed including the four latest generations of family. Hematoxylin and eosin staining and ultrastructural analysis were performed with the gingival tissue. Results: Examination of the family pedigree revealed that the patient III-2 represent the index patient of this family (initial patient with a mutation), which was transmitted to her daughter through an autosomal dominant mode of inheritance. The affected patients showed a generalized gingival overgrowth. The patient was treated with surgical procedures of gingivectomy and gingivoplasty. The diagnosis was confirmed by histopathology examination that showed a well-structured epithelium with elongated and thin papillae inserted in fibrous connective tissue with increased amount of collagen. The ultrastructural aspects of the tissue show collagen fibrils exhibiting their typically repeating banding pattern with some fibrils displaying loops at their end. Moreover, it was possible to seen in some regions fibrillar component presenting tortuous aspects and loss of the alignment among them. Conclusions: This HGF frequently resulted in both esthetic and functional problems. The genetic pattern of this Brazilian family suggested a new mutation, which was later transmitted by an autosomal dominant trait.

Key words:Gingival fibromatosis, genetic disease, pedigree, ultrastructure.

Clinical and histomorphometric characteristics of three different families with hereditary gingival fibromatosis

OBJECTIVE

To examine the histomorphologic and histomorphometric features of tissue from 3 unrelated families with hereditary gingival fibromatosis (HGF).

STUDY DESIGN

Twelve affected individuals from 3 HGF families and 3 control subjects were evaluated. Gingival samples were fixed in formalin and embedded in paraffin for hematoxylin and eosin stain to count the number of fibroblast and inflammatory cells. Sirius red staining was performed to quantitate the amount of collagen present.

RESULTS

Histomorphologic analysis of HGF showed extension of epithelial rete ridges into the underlying lamina propria and the presence of collagen bundles in the connective tissue. Analysis of the mean area fraction of collagen showed that there were significant increases in the collagen fraction for all HGF types compared with control subjects (P < .05). There were significant increases in the number of fibroblasts for HGFa and HGFb compared with control subjects (P < .05). The number of fibroblasts for HGFc were similar to that for control subjects.

CONCLUSIONS

The collagen fraction was significantly greater in all HGF types compared with controls. The number of fibroblasts was significantly increased in 2 of the 3 HGF types compared with controls. These data indicate that different mechanisms may be responsible for tissue enlargement in different forms of HGF.

Characterization of fibroblasts with Son of Sevenless-1 mutation

Although non-syndromic hereditary gingival fibromatosis (HGF) is genetically heterogeneous, etiologic mutations have been identified only in the Son of Sevenless-1 gene (SOS1). To test evidence of increased cell proliferation, we studied histological, morphological, and proliferation characteristics in monolayer and three-dimensional cultures of fibroblasts with the SOS1 g.126,142-126,143insC mutation. Histological assessment of HGF gingiva indicated increased numbers of fibroblasts (30%) and increased collagen (10%). Cell proliferation studies demonstrated increased growth rates and 5-bromo-2-deoxyuridine incorporation for HGF fibroblasts. Flow cytometry showed greater proportions of HGF fibroblasts in the G2/M phase. Attachment of HGF fibroblasts to different extracellular matrix surfaces demonstrated increased formation of protrusions with lamellipodia. HGF fibroblasts in three-dimensional culture showed greater cell proliferation, higher cell density, and alteration of surrounding collagen matrix. These findings revealed that increased fibroblast numbers and collagen matrix changes are associated with mutation of the SOS1 gene in vitro and in vivo.

Hereditary Gingival Fibromatosis: A Systematic Review

Generalized gingival enlargement can be caused by a variety of etiological factors. It can be inherited (hereditary gingival fibromatosis [HGF]); associated with other diseases characterizing a syndrome; or induced as a side effect of systemic drugs, such as phenytoin, cyclosporin, or nifedipine. HGF, previously known as elephantiasis gingivae, hereditary gingival hyperplasia, and hypertrophic gingiva, is a genetic disorder characterized by a progressive enlargement of the gingiva. This review will focus on diagnosis, treatment, and control of HGF. The pattern of inheritance, the histopathologic characteristics, and the known biologic and genetic features associated with HGF are also emphasized.

Gingival fibromatosis and significant tooth eruption delay in an 11-year-old male: a 30-month follow-up

This case report describes the dental management of an unusual case of idiopathic gingival fibromatosis with multiple impacted primary teeth, and the absence of eruption of permanent teeth, in an 11-year-old boy and at the 30-month follow-up. The patient presented with severely enlarged gingival tissues affecting both arches and multiple retained and non-erupted primary teeth. He had already been subjected to localized gingivectomies at the ages of 7 and 9 years. He had no known syndrome and there was no family history of any similar disorder. The patient was treated under general anaesthesia to remove the excessive gingival tissues using apically positioned flaps. During the surgical procedure, over-retained and unerupted impacted primary teeth were extracted in order to facilitate the eruption of the permanent successors. Two years postoperatively, there was no recurrence of the gingival enlargement. Overdentures were then constructed because none of the permanent teeth had yet erupted. Furthermore, pre-eruptive coronal resorption was detected radiographically affecting the crown of the unerupted 36. Thirty months postoperatively, no recurrence of gingival enlargement was seen, but the permanent teeth had still not erupted.

Hereditary gingival fibromatosis associated with generalized aggressive periodontitis: a case report

BACKGROUND

Hereditary gingival fibromatosis is a rare, genetically inherited overgrowth condition that is clinically characterized by a benign fibrous enlargement of maxillary and mandibular keratinized gingiva. A syndromic association between gingival fibromatosis and a wide variety of other genetically inherited disorders has been described. However, its coexistence with aggressive periodontitis has not been reported.

METHODS

A 24-year-old African-American female, patient (proband X, [Px]) reported with a chief complaint of tooth mobility and gingival enlargement. Clinical examination revealed moderate to severe gingival overgrowth on both mandible and maxilla. Generalized attachment loss and mobility of the teeth were observed. Radiographic evaluation demonstrated severe alveolar bone loss. The patient was diagnosed with gingival fibromatosis and aggressive periodontitis based on the clinical and radiographic findings. Her brother (Bx) and her mother (Mx) were evaluated and diagnosed with gingival fibromatosis suggesting that this is a dominant trait in the family and gingival fibromatosis might be of hereditary origin. In addition, the brother also exhibited localized aggressive periodontitis. Medical history revealed no other systemic or local contributory factors associated with the oral findings in any of the subjects.

RESULTS

Surgical therapy included internal bevel gingivectomy combined with open flap debridement procedures for Px and Bx. Only internal bevel gingivectomy was performed for Mx since there was mild bone resorption and no intrabony defects. At the time of surgery, gingival biopsies were obtained and fixed in 4% paraformaldehyde. Multiple serial sections were stained with hematoxylin and eosin. Microscopic evaluation of the gingival specimens revealed large parallel collagen bundles associated with scarce fibroblasts in the connective tissue. The collagen bundles reached into the subepithelial connective tissue where elongated rete-pegs were also observed. Following the completion of the treatment, no signs of recurrence or bone resorption were observed over 2-year follow-up.

CONCLUSIONS

This is the first report of hereditary gingival fibromatosis associated with aggressive periodontitis. Combined treatment comprising removal of fibrotic gingival tissue and traditional flap surgery for the elimination of intrabony defects represents a unique treatment approach in periodontal therapy. Two-year follow-up revealed that both the gingival overgrowth and the destructive lesions were successfully treated.

Hereditary gingival fibromatosis and expression of Ki-67 antigen: a case report

BACKGROUND

Hereditary gingival fibromatosis (HGF) is a fibrotic enlargement of the gingiva. The mechanism that leads to the accumulation of abnormal amounts of gingival tissue in HGF is still unknown. The aim of this report was to present the clinical and histopathologic characteristics of a patient with gingival fibromatosis and to evaluate the proliferation of HGF fibroblasts.

METHODS

We examined the proliferation rate of fibroblasts in this case by using Ki-67 immunohistochemical staining and compared the rate to fibroblasts of non-fibromatosis gingival tissues from 5 healthy patients serving as controls.

RESULTS

There were no Ki-67-positive cells in the lesional tissue, and the control gingiva revealed no immunostaining. The number of Ki-67 antigen-positive epithelial cell nuclei was observed to be low in the basal cell layers of hyperplastic gingival epithelia, similar to the control group.

CONCLUSIONS

In the present case, there was no increase in the proliferation rate of lesional fibroblasts observed by Ki-67 immunohistochemical staining as a proliferation marker; only the epithelium was stained. It seems likely that the underlying mechanism of HGF may be an increase in the biosynthesis of collagen and glycosaminoglycans rather than cell proliferation.