Immunohistochemical evaluation of inducible nitric oxide synthase in the epithelial lining of odontogenic cysts: A qualitative and quantitative analysis.

INTRODUCTION: The three common odontogenic cysts include radicular cysts (RCs), dentigerous cysts (DCs), and odontogenic keratocysts (OKCs). Among these 3 cysts, OKC is recently been classified as benign keratocystic odontogenic tumor attributing to its aggressive behavior, recurrence rate, and malignant potential. The present study involved qualitative and quantitative analysis of inducible nitric oxide synthase (iNOS) expression in epithelial lining of RCs, DCs, and OKCs, compare iNOS expression in epithelial linings of all the 3 cysts and determined overexpression of iNOS in OKCs which might contribute to its aggressive behavior and malignant potential. AIMS: The present study is to investigate the role of iNOS in the pathogenesis of OKCs, DCs, and RCs by evaluating the iNOS expression in the epithelial lining of these cysts. SUBJECTS AND METHODS: Analysis of iNOS expression in epithelial lining cells of 20 RCs, 20 DCs, and 20 OKCs using immunohistochemistry done. STATISTICAL ANALYSIS USED: The percentage of positive cells and intensity of stain was assessed and compared among all the 3 cysts using contingency coefficient. Kappa statistics for the two observers were computed for finding interobserver agreement. RESULTS: The percentage of iNOS-positive cells was found to be remarkably high in OKCs (12/20) -57.1% as compared to RCs (6/20) - 28.6% and DCs (3/20) - 14.3%. The interobserver agreement for iNOS-positive percentage cells was arrived with kappa values with OKCs → Statistically significant (P > 0.000), RCs → statistically significant (P > 0.001) with no significant values for DCs. No statistical difference exists among 3 study samples in regard to the intensity of staining with iNOS. CONCLUSIONS: Increased iNOS expression in OKCs may contribute to bone resorption and accumulation of wild-type p53, hence, making OKCs more aggressive.

Expression of MUC1 mucin in potentially malignant disorders, oral squamous cell carcinoma and normal oral mucosa: An immunohistochemical study.

BACKGROUND: Mucins alteration in glycosylation is associated with the development and progression of malignant diseases. Therefore, mucins are used as valuable markers to distinguish normal and disease conditions. Many studies on MUC1 expression have been conducted on variety of neoplastic lesions other than head and neck region. None of the study has made an attempt to show its significance in potentially malignant disorders (PMDs) and oral squamous cell carcinoma (OSCC). Hence, ours is one of the pioneer studies done to assess and evaluate the same. AIMS: This study aims to compare and correlate the expression of MUC1 mucin protein in normal oral mucosa (NOM), PMD's and OSCC by immunohistochemical method. MATERIALS AND METHODS: Institutional study, archived tissue sections of OSCC (n = 20), PMD's (n = 20) and NOM (n = 20) were immunostained for MUC1 mucin and percentage of positive cells evaluated. Results obtained were statistically analyzed using Kruskal-Wallis test, Mann-Whitney test and Student's t-test. RESULTS: The mean MUC1 mucin positive cells in the study groups were as follows, 40% in OSCC, 28% in PMD's and 0.75% in NOM. Higher mean immunohistochemical score was observed in OSCC group followed by PMD's group and NOM group. The difference in immunohistochemical score among the groups was found to be statistically significant (P < 0.001). CONCLUSION: The result of the current study suggests that determination of MUC1 mucin expression may be a parameter in the diagnosis of malignant behavior of PMD's to OSCC. MUC1 mucin expression may be a useful diagnostic marker for prediction of the invasive/metastatic potential of OSCC.

Inter- and intra-observer variability in three grading systems for oral epithelial dysplasia.

BACKGROUND AND OBJECTIVES: Management of oral premalignant lesions depends on clinical assessment and grading of oral epithelial dysplasia (OED), which remains one of the most important predictors of malignant potential. Numerous grading systems for OED exists with varying sets of assessing criteria and are largely considered subjective. The present study attempted to assess the inter- and intra-observer variability in three grading systems: Binary system, WHO (2005) and Ljubljana systems. METHODOLOGY: Histopathological grading of 63 cases of leukoplakia was performed by two oral pathologists and one general pathologist, who were blinded, using all the three grading systems at different time intervals and was repeated twice. Inter- and intra-observer variability was then evaluated by multivariate kappa analysis. RESULTS: Inter-observer agreement in the two set of observations was found to be "slight" in WHO (k = 0.001 and 0.039), "slight" and "poor" in binary (k = 0.108 and -0.007), "poor" and "slight" in Ljubljana's (k = -0.027 and 0.106) grading systems. Intra-observer agreement ranged from "slight" to "fair" (k = 0.128 and 0.295) in WHO, "fair" to "moderate" (k = 0.224 and 0.420) in binary and "slight" to "fair" (k = 0.161 and -0.353) in Ljubljana's grading systems. CONCLUSIONS: The binary system of classification proved to have an overall better inter- and intra-observer agreement. This study also showed better intra-observer agreement in all the grading systems as well as in individual histopathological parameters. Defining the individual parameters more objectively with the reproducible structuring of the grading systems and training of the pathologists would help reduce the variability in diagnosing dysplasia.

Evaluation and comparison of decalcification agents on the human teeth.

CONTEXT: In routine histopathology, decalcification of bone and teeth is often an essential and important step during tissue processing. Various decalcifying agents have been used in the past. The rate of decalcification and the effect of decalcifying agents on the tissue and its staining characteristics are two important parameters which influence the selection of decalcifying solutions. Though some agents remove the calcium ions completely and rapidly, they adversely affect the staining characteristics and may also damage the organic components. There have been very few studies which have systematically evaluated the efficacy of these agents in decalcifying dental hard tissues. AIMS: The present study was done to evaluate the rate of decalcification of six different decalcifying agents and also their effect on staining characteristics on dental hard tissues. MATERIALS AND METHODS: Six decalcifying agents namely, neutral ethylene diamine tetra acetic acid (EDTA) decalcifying solution, 5% nitric acid, Perenyi's fluid, formalin-nitric acid, 5% trichloracetic acid, and 10% formic acid were used to decalcify 24 natural teeth (four in each solution). The endpoint of decalcification was evaluated by radiographic and chemical methods. The decalcified teeth were then routinely processed, sectioned, and stained with hematoxylin and eosin stains. RESULTS: Neutral EDTA was the most considerate to the soft and hard tissues and 5% nitric acid was the least considerate to the tooth structure. CONCLUSIONS: Neutral EDTA, though being the slowest decalcifying agent among the six agents used in the study, gave excellent results for soft-tissue integrity, and best quality of both soft-tissue and hard-tissue stainings.

Florid cemento osseous dysplasia in association with dentigerous cyst.

We present a case of florid cemento-osseous dysplasia occurring in a 20-year-old Indian woman. The subject presented with three lesions involving the maxillary right quadrant, maxillary left quadrant and mandibular left quadrant. The mandibular left quadrant also demonstrated a cyst.The diagnosis was made by correlating the clinical presentation with that of the radiological and histopathological findings. This is a rare entity because of an unusual combination of Asian race along with the association of dentigerous cyst.