Mast cells distribution and variations in epithelium thickness and basement membrane in oral lichen planus lesion and oral lichenoid reaction

Mast cells in oral lichen planus and oral lichenoid lesions related to dental amalgam contact

The aim of this study was to analyze the expression of mast cell markers toluidine blue, c-kit, and tryptase and presence of mononuclear inflammatory cells in oral lichen planus (OLP) and oral lichenoid lesions related to dental amalgam. Nineteen specimens of OLP, OLLC, and healthy oral mucosa were selected. Mononuclear inflammatory cells were analyzed. Histochemical and immunohistochemical analyses were performed using toluidine blue, anti-c-kit and anti-tryptase reagents, and the results were quantified in areas A and B of connective tissue. Mast cells of all OLP and OLLC samples were positive for toluidine blue, c-kit, and tryptase. The density of toluidine blue+, c-kit+ and tryptase+ mast cells was higher in tissue with OLP and OLLC compared with healthy controls (p < 0.05). No difference was noted in mast cells density between OLP and OLLC (p > 0.05). The density of tryptase+ mast cells was higher in the subepithelial region (area A) than the region below it (Area B) in OLLC (p = 0.047). The mononuclear inflammatory cell density was higher in OLLC compared to OLP, but without statistical significance (p > 0.05). A positive statistical correlation was found between mononuclear immune cells and density of c-kit+ and tryptase+ mast cells in OLP (r = 0.943 and r = 0.886, respectively). Our data demonstrate that the etiopathogenesis process of OLP and OLLC modulates the expansion and degranulation of mast cells; mast cells density, however, was similar between OLP and OLLC. The distribution of mast cells appears to vary along the lamina propria.

Correlation of Mast Cell and Angiogenesis in Oral Lichen Planus, Dysplasia (Leukoplakia), and Oral Squamous Cell Carcinoma

OBJECTIVE

The aim of this study was to compare and correlate mast cell density (MCD) and microvessel density (MVD) between normal oral mucosa, oral lichen planus, various grades of dysplasia, and oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

The study comprised a total of 75 samples, of which 65 were archival tissue blocks of histopathologically confirmed cases, which included 10 cases of oral lichen planus, 25 cases of dysplasia (mild [n=10], moderate [n=10], and severe [n=5]), and 30 cases of OSCC (well differentiated [n=10], moderately differentiated [n=10], and poorly differentiated [n=10]), and 10 samples of normal oral mucosa. All the sections were immunohistochemically stained with anti-CD34 and counterstained with toluidine blue stain. Mean MCD and MVD were determined and analyzed using ANOVA test and compared between the lesions using Tukey HSD test. Pearson's correlation coefficient test was used to correlate these two factors between various lesions.

RESULTS

Mean MCD and mean MVD were found to be increased in all the lesions compared to normal oral mucosa, and the values were statically significant. Overall, MCD and MVD showed a significant positive correlation (r=0.640).

CONCLUSION

Increase of MCD and MVD and their positive correlation in all the lesions have emphasized their role in the pathogenesis and disease progression.

Histopathologic evaluation of oral lichen planus and oral lichenoid reaction: A comparative analysis based on basement membrane thickness and the distribution of mast cells

Background:

Lichen planus is a chronic mucocutaneous disease of unknown etiology with well-established clinical and microscopic features. Oral lichenoid reactions are a family of lesions triggered by contact with specific agents such as metallic restorative materials, resins and drugs. Oral lichenoid reactions share clinical and histological features of oral lichen planus (OLP) but has varied management options. Hence, the discrimination between these two lesions is a major challenge for clinicians as well as pathologists.

Aim:

Histopathologic categorization of OLP and oral lichenoid reaction by comparing the thickness of basement membrane and the distribution of mast cells using special stains.

Materials and Methods:

The test group consists of formalin-fixed paraffin-embedded blocks of OLP (n = 15), and oral lichenoid reactions (n = 15) obtained from the archives of the Department of Oral Pathology, Amrita School of Dentistry. Three serial sections of 4 μm thickness were cut from each block. The sections were stained with H & E, periodic acid-Schiff (PAS) and toluidine blue, respectively.

Results:

A significant increase in the maximum basement membrane thickness (BMT) was noticed in OLP when compared to oral lichenoid reaction. A definite increase was also noticed in the number of mast cells in OLP and oral lichenoid reaction when compared to normal oral mucosa. There was a statistically significant increase in the number of degranulated mast cells in the deeper connective tissue in oral lichenoid reaction when compared to OLP.

Conclusion:

OLP and oral lichenoid reactions are two different entities showing similar clinical and microscopic presentation. The histochemical analysis of basement membrane and mast cells in these lesions might provide a more authentic method for differentiating these two lesions and might be of utmost value in deciding the treatment options.

Quantitative and Qualitative Analysis of Mast Cells in Oral Lichen Planus and Its Effect on Basement Membrane Using Special Stains

Background:

Oral lichen planus (OLP) is characterized histologically by epithelial basal cell destruction and a dense subepithelial lymphocytic infiltrate. Mast cells (MCs) play a role in the pathogenesis and progression of the disease causing changes in the basement membrane (BM). BM is seen as continuous or fragmented, distinct or indistinct, and afibrillar or fibrillar extensions.

Aims and Objectives:

This study was done to demonstrate the BM using acriflavine stain in addition to hematoxylin and eosin (H-E) stain. An attempt was also made to study MC using Azure A stain and assess the degree of changes in the thickness of BM associated with degranulated MC in patients with OLP.

Materials and Methods:

A total of 66 paraffin-embedded tissue sections which included 30 inflamed gingival mucosa (IGM) and 36 OLP were stained with H-E stain, Azure A, and fluorescent periodic acid–acriflavine stain.

Results:

MC density was higher in OLP when compared with MC in IGM. Degranulated MCs were found in abundance in OLP. Thickness of BM was significantly less in OLP when compared with IGM. Significant fragmentation was seen in OLP when compared with BM of IGM.

Conclusion:

Degranulated MC in OLP may or may not alter the quality of BM but definitely seems to influence the thickness of the BM both directly and indirectly.

Differential metallothionein expression in oral lichen planus and amalgam-associated oral lichenoid lesions

Background

Oral lichen planus (OLP) is a chronic inflammatory disease mediated by T cells, which manifests as reticular (white) or erosive (red) lesions, that are eventually painful. Oral lichenoid lesion (OLL) are distinguished from OLP by the presence of precipitating factors. The aim of this study was to evaluate whether the presence of metallothionein, which is involved in anti-apoptotic pathways and the anti-oxidative response, could serve as a differential diagnostic for OLP and OLL.

Material and Methods

We evaluated the expression of metallothionein in 40 cases of OLP and 20 cases of OLL using immunohistochemistry.

Results and Conclusions

White OLP has higher concentrations of metallothionein than red OLP in basal and parabasal layers. Moreover, metallothionein was more frequently observed in the cytoplasm and nuclei of basal cells in OLP patients compared to the same regions of OLL cases. Metallothionein levels are related to OLP severity and may contribute to a differential diagnosis between OLP and OLL.

Key words:Oral lichen planus, oral lichenoid lesions, autoimmune disorders, metallothionein, immunohistochemistry.

Mast cell count in oral reactive lesions: A histochemical study

BACKGROUND

The aim of this study was to quantify the number of mast cells in focal reactive hyperplastic lesions of the oral cavity and to compare these two number of mast cells in normal gingival tissues and to correlate their presence with the state of connective tissue changes in reactive lesions and probably suggest a role for mast cells in these lesions.

MATERIALS AND METHODS

Patient records were retrieved during a 10 year period from 2001 to 2010. Data of all reactive hyperplasias namely focal fibrous hyperplasia, pyogenic granuloma (PG), peripheral ossifying fibroma (POF) and peripheral giant cell granuloma (PGCG) were reviewed and 10 cases seen in the gingiva were selected for each category and stained with 1% toluidine blue for mast cells. Statistical analysis was applied to see the significant differences between the groups and with the normal gingival tissue. One-way ANOVA-F and unpaired t-test was applied and significant differences were seen between the groups at 5% level of significance.

RESULTS

In this study, mast cell count was maximum in POF and fibrous hyperplasia (FH) followed by cases of PG and PGCG.

CONCLUSION

The number of mast cells was more numerous in POF and FH suggesting that mast cell activation is a characteristic feature of chronic inflammation, a condition that may lead to fibrosis as a result of increased collagen synthesis by fibroblasts.