Histological grading of oral epithelial dysplasia: revisited

OralImmunoAnalyser: a software tool for immunohistochemical assessment of oral leukoplakia using image segmentation and classification models

Oral cancer ranks sixteenth amongst types of cancer by number of deaths. Many oral cancers are developed from potentially malignant disorders such as oral leukoplakia, whose most frequent predictor is the presence of epithelial dysplasia. Immunohistochemical staining using cell proliferation biomarkers such as ki67 is a complementary technique to improve the diagnosis and prognosis of oral leukoplakia. The cell counting of these images was traditionally done manually, which is time-consuming and not very reproducible due to intra- and inter-observer variability. The software presently available is not suitable for this task. This article presents the OralImmunoAnalyser software (registered by the University of Santiago de Compostela-USC), which combines automatic image processing with a friendly graphical user interface that allows investigators to oversee and easily correct the automatically recognized cells before quantification. OralImmunoAnalyser is able to count the number of cells in three staining levels and each epithelial layer. Operating in the daily work of the Odontology Faculty, it registered a sensitivity of 64.4% and specificity of 93% for automatic cell detection, with an accuracy of 79.8% for cell classification. Although expert supervision is needed before quantification, OIA reduces the expert analysis time by 56.5% compared to manual counting, avoiding mistakes because the user can check the cells counted. Hence, the SUS questionnaire reported a mean score of 80.9, which means that the system was perceived from good to excellent. OralImmunoAnalyser is accurate, trustworthy, and easy to use in daily practice in biomedical labs. The software, for Windows and Linux, with the images used in this study, can be downloaded from https://citius.usc.es/transferencia/software/oralimmunoanalyser for research purposes upon acceptance.

Demystifying oral epithelial dysplasia: a histological guide

Oral epithelial dysplasia is a histologically diagnosed potentially premalignant disorder of the oral mucosa, which carries a risk of malignant transformation to squamous cell carcinoma. The diagnosis and grading of oral epithelial dysplasia is challenging, with cases often referred to specialist oral and maxillofacial pathology centres for second opinion. Even still there is poor inter-examiner and intra-examiner agreement in a diagnosis. There are a total of 28 features of oral epithelial dysplasia listed in the 5th edition of World Health Organization classification of tumours of the head and neck. Each of these features is poorly defined and subjective in its interpretation. Moreover, how these features contribute to dysplasia grading and risk stratification is even less well defined. This article discusses each of the features of oral epithelial dysplasia with examples and provides an overview of the common mimics, including the normal histological features of the oral mucosa which may mimic atypia. This article also highlights the paucity of evidence defining these features while offering suggested definitions. Ideally, these definitions will be refined, and the most important features identified to simplify the diagnosis of oral epithelial dysplasia. Digital whole slide images of the figures in this paper can be found at: https://www.pathogenesis.co.uk/r/demystifying-dysplasia-histology-dataset.

Genome sequencing reveals molecular subgroups in oral epithelial dysplasia

This study aimed to analyze the molecular characteristics of oral epithelial dysplasia (OED), highlighting the pathways and variants of genes that are frequently mutated in oral squamous cell carcinoma (OSCC) and other cancers. Ten archival OED cases were retrieved for retrospective clinicopathological analysis and exome sequencing. Comparative genomic analysis was performed between high-grade dysplasia (HGD) and low-grade dysplasia (LGD), focusing on 57 well-known cancer genes, of which 10 were previously described as the most mutated in OSCC. HGD cases had significantly more variants; however, a similar mutational landscape to OSCC was observed in both groups. CASP8+FAT1/HRAS, TP53, and miscellaneous molecular signatures were also present. FAT1 is the gene that is most affected by pathogenic variants. Hierarchical divisive clustering showed division between the two groups: "HGD-like cluster" with 4HGD and 2LGD and "LGD-like cluster" with 4 LGD. MLL4 pathogenic variants were exclusively in the "LGD-like cluster". TP53 was affected in one case of HGD; however, its pathway was usually altered. We describe new insights into the genetic basis of epithelial malignant transformation by genomic analysis, highlighting those associated with FAT1 and TP53. Some LGDs presented a similar mutational landscape to HGD after cluster analysis. Perhaps molecular alterations have not yet been reflected in histomorphology. The relative risk of malignant transformation in this molecular subgroup should be addressed in future studies.

Ki-67 Expression as a Prognostic Marker: A Comparative Immunohistochemical Analysis of Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma

Introduction Oral dysplasia is a frequent precancerous condition that may lead to oral cancer. The histopathologic abnormalities exhibited in a chronic, progressive, and premalignant condition of the oral mucosa are referred to as oral epithelial dysplasia (OED). It might show up as erythroplakia, leukoplakia, or leukoerythroplakia. OED is a premalignancy histologic marker that predicts a higher likelihood of squamous cell carcinoma development. Aims and objectives The aim of this study is to identify an association between Ki-67 protein expression and histological grading of OED and oral squamous cell carcinoma (OSCC) and to compare the expression of Ki-67 in different grades of OED and OSCC with the prognosis. Materials and methods The current retrospective research is focused on evaluating epithelial dysplasia and analyzing the function of Ki-67 as a prognostic marker after receiving institutional ethical approval. Group I - normal oral mucosa (NOM), Group II - OED, and Group III - OSCC were included in the study. For statistical analysis, SPSS Statistics version 21.0 (IBM Corp. Released 2021. IBM SPSS Statistics for Windows, Version 28.0. Armonk, NY: IBM Corp) was utilized. The Cox regression model was employed to look at interactions between various prognostic variables. At p<0.05, differences were deemed statistically significant. Results Ki-67 expression was confined to the basal layers in the normal oral epithelium and in the basal, suprabasal, and spinous layers in OED. Ki-67 positive cells were mostly found on the perimeter of well, moderate, and poorly differentiated OSCC tumor nests with Ki-67 positive cells scattered throughout OSCC. According to statistical analysis, there is a substantial difference in expression between OED and NOM, OSCC and NOM, and OED and OSCC. Conclusion Our study showed that there is a progressive increase in Ki-67 expression across various grades of OED, and the highest expression was noted in OSCC. Early identification and prompt treatment will help in improving the quality of life of such patients.

Prediction of malignant transformation and recurrence of oral epithelial dysplasia using architectural and cytological feature specific prognostic models

Oral epithelial dysplasia (OED) is a precursor state usually preceding oral squamous cell carcinoma (OSCC). Histological grading is the current gold standard for OED prognostication but is subjective and variable with unreliable outcome prediction. We explore if individual OED histological features can be used to develop and evaluate prognostic models for malignant transformation and recurrence prediction. Digitised tissue slides for a cohort of 109 OED cases were reviewed by three expert pathologists, where the prevalence and agreement of architectural and cytological histological features was assessed and association with clinical outcomes analysed using Cox proportional hazards regression and Kaplan-Meier curves. Within the cohort, the most prevalent features were basal cell hyperplasia (72%) and irregular surface keratin (60%), and least common were verrucous surface (26%), loss of epithelial cohesion (30%), lymphocytic band and dyskeratosis (34%). Several features were significant for transformation (p < 0.036) and recurrence (p < 0.015) including bulbous rete pegs, hyperchromatism, loss of epithelial cohesion, loss of stratification, suprabasal mitoses and nuclear pleomorphism. This led us to propose two prognostic scoring systems including a '6-point model' using the six features showing a greater statistical association with transformation and recurrence (bulbous rete pegs, hyperchromatism, loss of epithelial cohesion, loss of stratification, suprabasal mitoses, nuclear pleomorphism) and a 'two-point model' using the two features with highest inter-pathologist agreement (loss of epithelial cohesion and bulbous rete pegs). Both the 'six point' and 'two point' models showed good predictive ability (AUROC ≥ 0.774 for transformation and 0.726 for recurrence) with further improvement when age, gender and histological grade were added. These results demonstrate a correlation between individual OED histological features and prognosis for the first time. The proposed models have the potential to simplify OED grading and aid patient management. Validation on larger multicentre cohorts with prospective analysis is needed to establish their usefulness in clinical practice.

Histological features of differentiated dysplasia in the oral mucosa: A review of oral invasive squamous cell carcinoma cases diagnosed with benign or low-grade dysplasia on previous biopsies

The diagnosis of oral squamous cell carcinoma is sometimes delayed. Recently, the concept of differentiated dysplasia in the oral mucosa was proposed, and we attempted to elucidate the histologic features of differentiated dysplasia in the oral mucosa. Two pathologists reviewed 38 small biopsy cases of patients diagnosed with benign to low grade dysplasia in the first biopsy, but were diagnosed with invasive carcinoma after excisional biopsy within 2 years. Of these, 29 cases were suspected of having differentiated dysplasia, which histologically showed "abnormal variation in nuclear size and shape", "increased number and size of nucleoli", and "loss of polarity of basal cells". In addition to the features observed in classic dysplasia, "premature keratinization in single cells" and "loss of epithelial cell cohesion" were characteristically observed. These two findings were often observed only in the lower half of the epithelium, but not in the full layer of the epithelium. Histological findings of oral differentiated dysplasia were very similar to those of differentiated vulvar intraepithelial neoplasia. "Premature keratinization in single cells" and "loss of epithelial cell cohesion" are specific pathological findings of oral differentiated dysplasia. Oral differentiated dysplasia is considered as a part of the broad spectrum of oral dysplasia that exhibits morphological characteristics different from classic dysplasia rather than being a separate entity. The diagnosis of oral differentiated dysplasia is expected to reduce the delayed diagnosis and improve the prognosis and post-treatment quality of life of oral cavity cancer patients.

Predicting progression of low-grade oral dysplasia using brushing based DNA ploidy and Chromatin Organization analysis

Most oral cancers arise from oral potentially malignant lesions, which show varying grades of dysplasia. Risk of progression increases with increasing grade of dysplasia, however risk prediction among oral low-grade dysplasia (LGDs) i.e., mild and moderate dysplasia can be challenging as only 5-15% transform. Moreover, grading of dysplasia is subjective and varies with the area of the lesion being biopsied. To date, no biomarkers or tools are used clinically to triage oral LGDs. This study utilizes a combination of DNA ploidy and chromatin organization (CO) scores from cells obtained from lesion brushings to identify oral LGDs at high-risk of progression. A total of 130 lesion brushings from patients with oral LGDs were selected of which 16 (12.3%) lesions progressed to severe dysplasia or cancer. DNA ploidy and CO scores were analyzed from nuclear features measured by our in-house DNA image cytometry (DNA-ICM) system and used to classify brushings into low risk and high risk. A total of 57 samples were classified as high-risk of which 13 were progressors. High-risk DNA brushing was significant for progression (P = 0.001) and grade of dysplasia (P = 0.004). Multivariate analysis showed high-risk DNA brushing showed 5.1 to 8-fold increased risk of progression, a stronger predictor than dysplasia grading and lesion clinical features. DNA-ICM can serve as a non-invasive, high throughput tool to identify high-risk lesions several years prior to transformation. This will help clinicians focus on such lesions while low-risk lesions may be spared from unnecessary biopsies.

Tissue biomarkers for predicting the risk of oral cancer in patients diagnosed with oral leukoplakia: A systematic review

OBJECTIVES

We performed a systematic review to evaluate the published biomarkers related to oral leukoplakia (OL), aiming to identify the biomarkers that indicate any future risk of cancer in patients with oral leukoplakia.

METHODS

A search strategy was developed for three main electronic databases: PubMed, Cochrane Library, and EBSCO, and also for Google Scholar, until February 28, 2020. The study selection was performed in a two-phase process aiming at studies assessing tissue biomarkers for "malignant transformation of OL." Risk of bias analysis of included studies was performed using the Quality in Prognosis Studies Tool.

RESULTS

From 3,130 articles initially identified by searching databases, a total of 46 studies were included in this systematic review, with a combined sample of 3,783 patients, of whom 1,047 presented with malignant transformation of a previously diagnosed OL as reported by the authors. The cancer incidence in the whole group was 27.6% (range: 5.4% to 54.1%). The studies were derived from different geographic areas, including Asia (n = 21), Europe (n = 15), North America (n = 9), and Oceania (n = 1). There were 49 different molecular biomarkers evaluated in the 46 included studies: p53 and podoplanin proteins were the most frequently reported, followed by abnormalities at particular chromosomal loci (e.g., LOH). Risk of bias analysis revealed concerns associated with "measurement of prognostic factor," "study confounding" and "statistical analysis and reporting."

CONCLUSIONS

Substantial heterogeneity and lack of standardized reporting of data among the studies were identified. The most promising biomarkers reported to have a significant association with the malignant transformation in OL included podoplanin and chromosomal loci abnormalities. A critical examination of the follow-up studies on OL published so far indicated that tissue biomarkers that could predict the risk of oral cancer in patients with OL are still in a discovery phase.

Current challenges and the diagnostic pitfalls in the grading of epithelial dysplasia in oral potentially malignant disorders: A review

Oral cancer is one of the common cancers in the world causing high morbidity. Development of cancer is preceded by certain asymptomatic clinical lesions and conditions all together known as 'oral potentially malignant disorders'. Histologically they are represented by the term 'oral epithelial dysplasia'. The degree of severity of dysplasia is determined in the form of 'grade'. Despite the existence of several grading systems proposed by various scholars, it is still a challenging task for the Pathologists to grade dysplasia accurately for the proper diagnosis of the disease and to follow preferable treatment plans. This review aims to focus on the current challenges and the diagnostic pitfalls in the grading of oral epithelial dysplasia in various oral potentially malignant disorders.

Morphometric Analysis of Suprabasal Cell Layer in Oral Epithelial Dysplasia: A Computer-assisted Microscopic Study

Background:

Oral leukoplakia is the most common precancerous lesion. Various grading systems based on histological findings have been proposed for dysplasia. Recently, computer-assisted morphometric analysis has been established to reduce the interobserver and intraobserver variability during the histological grading of epithelial dysplasia. This study was undertaken to establish the morphometric changes in the suprabasal cell layer of different grades of oral epithelial dysplasia.

Materials and Methods:

Forty paraffin-embedded tissue sections (10 normal mucosa, 10 mild dysplasia, 10 moderate dysplasia, and 10 severe dysplasia cases) were stained using hematoxylin and eosin stain, and analyzed for cellular and nuclear morphometry using binocular microscope.

Results:

Our results showed that values of nuclear area, nuclear perimeter, nuclear volume density, and nuclear/cytoplasmic (N/C) ratio were increased gradually in dysplasia compared to control groups and the values were statistically significant (P = 0.001). Nuclear diameter and cellular area were increased in dysplasia when compared to control group (P = 0.001). Mild and moderate dysplasia showed decreased value of nuclear form factor compared to control group, whereas severe dysplasia showed highest value. A fair correlation was found when comparing histological grading and grouping based on nuclear area, nuclear perimeter, N/C ratio, and nuclear volume density.

Conclusion:

Nuclear features reflect cell behavior, and its morphometric analysis can be considered as a reliable tool for differentiating various grades of epithelial dysplasia.

Demographic and Clinicopathologic Features of Actinic Cheilitis and Lip Squamous Cell Carcinoma: a Brazilian Multicentre Study

Data on the occurrence and clinicopathological characteristics of actinic cheilitis (AC) and lip squamous cell carcinoma (LSCC) are well studied; however, they are based on studies limited to a single centre. Herein, we described the frequency of AC and LSCC submitted to microscopic examination from representative geographic regions of Brazil. A retrospective multicentre study was performed on biopsies obtained from 1953 to 2018 at 10 Brazilian oral and maxillofacial pathology centres. A total of 198,709 biopsy specimens were surveyed. Sociodemographic data and clinicopathologic characteristics were analysed. A total of 2017 cases of ACs (1.0%) and 850 cases of LSCCs (0.4%) were recorded. A strong fair-skinned (> 87%) male (> 70%) predilection was observed in both conditions. The mean age was 54.8 ± 18.7 for individuals with AC and 57.8 ± 19.0 for individuals with LSCC. The most commonly affected site was the lower lip (> 90%). This is a large multicentre study of AC and LSCC from Brazil. The frequency and clinicopathological features of AC and LSCC were similar to those described worldwide. This study provides robust and representative epidemiological data of these conditions for the scientific community.

Preclinical Prevention Trial of Calcitriol: Impact of Stage of Intervention and Duration of Treatment on Oral Carcinogenesis

The anticancer activity of 1,25-dihydroxyvitamin D3 (1,25(OH)₂D₃ or calcitriol) has been widely reported in preclinical models. However, systematic investigation into the chemopreventive potential of calcitriol against the spectrum of oral carcinogenesis has not been performed. To address this gap in knowledge, we conducted a preclinical prevention trial of calcitriol in the 4-nitroquinoline-1-oxide (4NQO) oral carcinogenesis model. C57BL/6 mice were exposed to the carcinogen 4NQO in drinking water for 16 weeks and randomized to control (4NQO only) or calcitriol arms. Calcitriol (0.1 μg i.p, Monday, Wednesday, and Friday) was administered for (i) 16 weeks concurrently with 4NQO exposure, (ii) 10 weeks post completion of 4NQO exposure, and, (iii) a period of 26 weeks concurrent with and following 4NQO exposure. Longitudinal magnetic resonance imaging (MRI) was performed to monitor disease progression until end point (week 26). Correlative histopathology of tongue sections was performed to determine incidence and multiplicity of oral dysplastic lesions and squamous cell carcinomas (SCC). Vitamin D metabolites and calcium were measured in the serum using liquid chromatography-mass spectrometry (LC-MS/MS) and colorimetric assay, respectively. Renal CYP24A1 (24-hydroxylase) and CYP27B1 (1α-hydroxylase) expression was measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Immunostaining of tongue sections for vitamin D receptor (VDR), CYP24A1, and Ki67 was also performed. Non-invasive MRI enabled longitudinal assessment of lesions in the oral cavity. Calcitriol administered concurrently with 4NQO for 16 weeks significantly (P < .001) decreased the number of premalignant lesions by 57% compared to 4NQO only controls. Mice treated with calcitriol for 26 weeks showed highest renal CYP24A1, lowest serum 1,25(OH)₂D₃ levels and highest incidence of invasive SCC. Immunohistochemistry revealed increased VDR, CYP24A1 and Ki67 staining in dysplastic epithelia compared to normal epithelium, in all four groups. Collectively, our results show that the effects of calcitriol on oral carcinogenesis are critically influenced by the stage of intervention and duration of exposure and provide the basis for exploring the potential of calcitriol for prevention of OSCC in the clinical setting.

Recent Changes of Classification for Squamous Intraepithelial Lesions of the Head and Neck

CONTEXT

- Interpretation of atypical squamous lesions of the head and neck has always been a nettlesome task for pathologists. Moreover, many different grading systems for squamous intraepithelial lesions have been proposed in past decades. The recent World Health Organization 2017 classification presents 2 types of 2-tier systems for laryngeal and oral precursor lesions.

OBJECTIVE

- To review the recent changes in classification and the clinical significance for squamous intraepithelial lesions of the head and neck.

DATA SOURCES

- Personal experience and data from the literature.

CONCLUSIONS

- The 2-tier grading system for laryngeal dysplasia, presented by World Health Organization in 2017, is expected to improve diagnostic reproducibility and clinical implication. However, the diagnostic criteria for low-grade dysplasia do not distinguish it clearly from basal cell hyperplasia. The World Health Organization 2017 classification of oral epithelial dysplasia remains unclear, and complicated and variable grading systems still make head and neck intraepithelial lesions difficult to interpret.

Impact of Age on Disease Progression and Microenvironment in Oral Cancer

Despite the recognized link between aging and cancer, most preclinical studies in experimental tumor models are conducted with 6- to 8-wk-old rodents. The goal of the present study was to examine the impact of age on tumor incidence, growth, and microenvironmental characteristics in mouse models of head and neck squamous cell carcinoma (HNSCC). Experimental studies were conducted with the 4-nitroquinoline-oxide (4NQO) oral carcinogenesis model and orthotopic FaDu HNSCC xenografts, established in young (7 to 12 wk of age) and old (65 to 70 wk of age) female C57BL/6 mice ( n = 44; 4NQO model) and severe combined immunodeficient mice ( n = 13; HNSCC xenografts). Noninvasive whole body magnetic resonance imaging revealed increased subcutaneous and visceral fat in aging animals of both strains. On histologic examination, a higher incidence ( P < 0.001) of severe dysplasia/invasive squamous cell carcinoma was observed in old mice (92%) as compared with young mice (69%). Old C57BL/6 mice exposed to 4NQO exhibited increased incidence of oral and extraoral (peritoneal masses) neoplasms (42%) versus their young counterparts ( P < 0.05). The incidence of extraoral neoplasms was significantly lower (16%) in the younger cohort. Interestingly, no difference in growth rate and oxygen saturation was observed between orthotopic FaDu xenografts established in old and young severe combined immunodeficient mice. Our observations suggest that host age may have an impact on the growth kinetics and progression of HNSCC in the immunocompetent 4NQO model. Further investigation into the impact of aging on tumor response to preventive and therapeutic intervention is warranted.

Unusual Histological Evidence of Dysplasia in a Case of Oral Pemphigus Vulgaris: A Potential Diagnostic Challenge

This report describes the management of an unusual case of oral pemphigus vulgaris (PV). The patient was referred for a painful single bullous lesion together with a small proliferative area localized in the soft palate. Histology and direct immunofluorescence data were consistent for PV but disclosed unusual signs of high-grade dysplasia in the proliferative area. At surgical removal of the dysplastic area 1 week after the start of cortisone therapy there was no evidence of dysplasia. Histological signs of high-grade dysplasia in oral mucosa are often associated with concurrent or subsequent carcinoma. However, severe inflammation may induce reactive epithelial cell changes and hence mimic histologic dysplasia. Pathologic evaluation of dysplasia in an inflammatory disease like PV may be a diagnostic challenge and a careful pathological evaluation is advisable before choosing between surgical and medical approach.

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.

Role of tissue eosinophils in oral Leukoplakia: A pilot study

CONTEXT

Tissue eosinophilia in oral squamous cell carcinoma has been well - recognized. Studies have reported both favorable and unfavorable prognoses associated with tissue eosinophils in oral squamous cell carcinoma. However, the role of eosinophils in the development of tumor is still unclear.

AIMS

The present study was an attempt to elucidate the potential role of tissue eosinophils in oral leukoplakia, a potentially malignant lesion.

SETTINGS AND DESIGN

To count eosinophils in tissues of normal subjects and oral leukoplakia cases. To compare tissue eosinophil count (TEC) between normal and oral leukoplakia cases. To compare TEC between dysplastic and non-dysplastic cases of oral leukoplakia and to correlate with degree of epithelial dysplasia.

MATERIALS AND METHODS

A total of 85 cases (59 cases of oral leukoplakia and 26 normal oral tissues) constituted the study material. Tissue eosinophils were counted in 10 different high- power fields.

STATISTICAL ANALYSIS USED

Non-parametric tests (Mann-Whitney U-test, Kruskal-Wallis test, Mann-Whitney post hoc analysis and Spearman's correlation statistics).

RESULTS

Mean eosinophil count (MEC) in oral leukoplakia cases was significantly more when compared to normal subjects. MEC in dysplastic cases of oral leukoplakia was significantly more when compared to those without epithelial dysplasia (Mann-Whitney U-test). Furthermore, MEC was directly proportional to the degree of epithelial dysplasia (Spearman's correlation statistics).

CONCLUSIONS

TEC may be used as an adjunct to predict the malignant transformation of dysplastic cases of oral leukoplakia. Eosinophilic infiltration in oral dysplastic cases should prompt a thorough evaluation for invasiveness, especially when features of invasion are absent or suspected in smaller biopsy specimens. Use of TEC as a prognostic indicator demands larger sample size and mandates long-term follow-up.

Expression of NF-κB and IL-6 in oral precancerous and cancerous lesions: An immunohistochemical study

Background

The purpose of this study was to evaluate the immunohistochemical expression of NF-κB and IL-6 in oral premalignant and malignant lesions and to investigate their possible correlation with the presence of subepithelial inflammation.

Material and Methods

Thirty two oral premalignant lesions, clinically compatible with leukoplakia or erythroplakia, were investigated. Microscopically, 11 of them showed hyperkeratosis and acanthosis (epithelial hyperplasia) and 21 showed dysplasia of varying degrees. Nine cases of OSCC and four control cases of normal oral mucosa were also included in the study. Immunohistochemical staining with NF-κB (p65) and IL-6 was performed. IL-6 and nuclear NF-κB staining were assessed as positive or negative. For cytoplasmic localization of NF-κB, a total score combining intensity and percentage of positive epithelial cells was additionally calculated. The presence of inflammation was also recorded.

Results

Intensity and total scores for NF-κΒ cytoplasmic immunostaining showed a statistically significant gradual increase from normal mucosa to OSCC (p=0.012 and p=0.026 respectively). Non-statistically significant increased NF-κΒ nuclear localization was detected in dysplasias and OSCCs. Positive statistical correlation was detected between the presence of inflammation and IL-6 expression (p=0.015). No correlation between NF-κΒ and IL-6 was detected.

Conclusions

NF-κΒ is activated in the early stages of oral carcinogenesis. IL-6 may have an NF-κΒ-independent role, possibly through regulation of the inflammatory response.

Key words:NF-κB, IL-6, immunohistochemistry, oral squamous cell carcinoma, oral precancerous lesion.

Grading of oral epithelial dysplasia: Points to ponder

Background:

Over the years many grading systems have been put forward in an attempt to obtain objectivity in grading oral epithelial dysplasia (OED). However, despite these efforts variability remains unresolved. Our study aimed to evaluate the intra- and inter-observer variability in grading OED, using World Health Organization (WHO), Smith and Pindborg and Ljubljana grading systems and discuss the possible reasons for this variability if any.

Materials and Methods:

Three oral pathologists graded 50 slides of OED independently twice at a time interval of 3 months. Variability was evaluated by multivariate kappa analysis.

Results:

Intra-observer reproducibility ranged from moderate to good in WHO system, fair to moderate in Smith and Pindborg system and moderate to poor in Ljubljana grading system. Inter-observer agreement was found to be fair in WHO, poor in Smith and Pindborg system and poor to fair in Ljubljana grading systems. Intra-observer reproducibility of the dysplastic features in WHO system was good for all except the loss of polarity and basilar hyperplasia for first observer and enlarged nucleoli for the third observer. Inter-observer agreement was good for increased number of mitosis and nuclear hyperchromatism. Intra-observer reproducibility and inter-observer agreement were found to be best in the WHO grading system though variability within this system still existed.

Conclusion:

There is a need for an International body of pathologists to come to a consensus on a more definable grading system to resolve the issue of variability in grading dysplasia.

Pseudoepitheliomatous hyperplasia after diode laser oral surgery. An experimental study

Background

To examine the process of epithelial reparation in a surgical wound caused by diode laser.

Material and Methods

An experimental study with 27 Sprage-Dawley rats was undertaken. The animals were randomly allocated to two experimental groups, whose individuals underwent glossectomy by means of a diode laser at different wattages, and a control group treated using a number 15 scalpel blade. The animals were slaughtered at the 2nd, 7th, and 14th day after glossectomy. The specimens were independently studied by two pathologists (blinded for the specimens’ group).

Results

At the 7th day, re-epithelisation was slightly faster for the control group (conventional scalpel) (p=0.011). At the 14th day, complete re-epithelization was observed for all groups. The experimental groups displayed a pseudoepitheliomatous hyperplasia.

Conclusions

It is concluded that, considering the limitations of this kind of experimental studies, early re-epithelisation occurs slightly faster when a conventional scalpel is used for incision, although re-epithelisation is completed in two weeks no matter the instrument used. In addition, pseudoepitheliomatous hyperplasia is a potential event after oral mucosa surgery with diode laser. Knowledge about this phenomenon (not previously described) may prevent diagnostic mistakes and inadequate treatment approaches, particularly when dealing with potentially malignant oral lesions.

Key words:Diode laser, animal model, oral biopsy, oral cancer, oral precancer, pseudoepitheliomatous hyperplasia.

Evaluation of AgNORs in Oral Potentially Malignant Lesions

Oral squamous cell carcinoma (OSCC) is usually preceded by detectable mucosal changes, as leukoplakias and erythroplakia. Histologically, these lesions can range from hyperkeratosis and acanthosis to epithelial dysplasia and even OSCC. The aim of this study was to investigate the proliferative activity, using AgNORs quantification proteins, in low- and high-risk oral epithelial dysplasia, OSCC, and nondysplastic epithelium (inflammatory fibrous hyperplasia). The sample was divided into 4 groups: G1: 10 cases of inflammatory fibrous hyperplasia (IFH), G2: 11 cases of low-risk epithelial dysplasia (LD), G3: 10 cases of high-risk epithelial dysplasia (HD), and G4: 11 cases of OSCC. The quantitative analysis was performed using an image processing software in photomicrographs at 1000x magnification. The one-way ANOVA was used for comparison of the mean AgNORs counts between the study groups. The mean AgNORs count was significantly higher (P ≤ 0.01) in OSCC when compared to IFH and the LD; however, it was not statistically different from HD. The mean number of LD was significantly lower than the HD and OSCC, with no difference related to IFH. AgNORs quantification can be an important and cheap method to help in the determination of the degree of epithelial dysplasia and, consequently, in the analysis of their potential for malignant transformation.

Validation of the diagnostic utility of salivary interleukin 8 in the differentiation of potentially malignant oral lesions and oral squamous cell carcinoma in a region with high endemicity

OBJECTIVE

To evaluate the clinical utility of salivary interleukin 8 (IL-8) in the differential diagnosis of potentially malignant lesions (PMLs) and oral squamous cell carcinoma (OSCC) in a region with high oral cancer prevalence.

STUDY DESIGN

Saliva and blood samples were collected from 100 participants in each group (OSCC, PMLs, and healthy controls). Serum and salivary IL-8 levels were measured by enzyme-linked immunosorbent assay. The data were subjected to appropriate statistical analysis.

RESULTS

A significant increase in levels of serum and salivary IL-8 was found in OSCC compared with PMLs and healthy controls. Receiver operating characteristic curve analysis found salivary IL-8 to have superior sensitivity in detecting OSCC. A significant increase in IL-8 levels based on the histologic grading of OSCC was also observed.

CONCLUSIONS

This study confirms that salivary IL-8 can be a potent marker that can be used as a tool in the differential diagnosis of PMLs and OSCC.

Genomic DNA copy number alterations from precursor oral lesions to oral squamous cell carcinoma

Oral cancer is a multifactorial disease in which both environmental and genetic factors contribute to the aetiopathogenesis. Oral cancer is the sixth most common cancer worldwide with a higher incidence among Melanesian and South Asian countries. More than 90% of oral cancers are oral squamous cell carcinoma (OSCC). The present study aimed to determine common genomic copy number alterations (CNAs) and their frequency by including 12 studies that have been conducted on OSCCs using array comparative genomic hybridization (aCGH). In addition, we reviewed the literature dealing with CNAs that drive oral precursor lesions to the invasive tumors. Results showed a sequential accumulation of genetic changes from oral precursor lesions to invasive tumors. With the disease progression, accumulation of genetic changes increases in terms of frequency, type and size of the abnormalities, even on different regions of the same chromosome. Gains in 3q (36.5%), 5p (23%), 7p (21%), 8q (47%), 11q (45%), 20q (31%) and losses in 3p (37%), 8p (18%), 9p (10%) and 18q (11%) were the most common observations among those studies. However, losses are less frequent than gains but it appears that they might be the primary clonal events in causing oral cancer.

Correlation between histological grading and ploidy status in potentially malignant disorders of the oral mucosa: A flow cytometric analysis

Background:

Histopathological grading of oral dysplastic lesions is the method of choice for evaluating malignant and potentially malignant disorders. Owing to inter- and intra-observer variability, determination of the DNA ploidy status of lesions may serve as an adjunct in the prediction of malignant transformation.

Aim:

To correlate histopathological grading and ploidy status in potentially malignant and malignant disorders of the oral mucosa.

Settings and Design:

A pilot study was done with 30 patients (10 patients with oral potentially malignant disorders predominantly leukoplakia, 10 patients with oral malignant lesions and 10 patients with normal mucosa).

Materials and Methods:

Incisional biopsy was done after isolating the biopsy site with 1% Toluidine blue staining. Two sections of the tissue were removed and sent for histopathological and Flow-cytometric analysis respectively. Histopathological diagnosis was obtained and compared with Flow-cytometric results which were graded as diploid and aneuploid. Further, the S – phase fraction, DNA index were also calculated to evaluate the severity of malignant transformation or malignancy.

Statistical Analysis:

The results were analyzed using Pearson Chi-Square Test.

Results:

There exists a significant correlation between histopathology and ploidy status in both potentially malignant and malignant group. (P = 0.002).

Conclusion:

The data from this study has shown that DNA Ploidy analysis can be used as a valuable tool in assessing the carcinomatous progression of potentially malignant and malignant lesions.

The pathological significance of Notch1 in oral squamous cell carcinoma

Notch signaling has been reported to be involved in several types of malignant tumors; however, the role and activation mechanism of Notch signaling in oral squamous cell carcinoma (OSCC) remains poorly characterized. The purpose of this study was to elucidate the pathological significance of Notch signaling and its activation mechanism in the development and progression of OSCC. In this study, we showed that the expression of Notch1 and intracellular Notch domain (NICD) are upregulated in OSCCs. In addition, Notch1 and NICD were found to be characteristically localized at the invasive tumor front. TNF-α, a major inflammatory cytokine, significantly activated Notch signaling in vitro. In a clinicopathological analysis, Notch1 expression correlated with both the T-stage and the clinical stage. Furthermore, loss of Notch1 expression correlated with the inhibition of cell proliferation and TNF-α-dependent invasiveness in an OSCC cell line. In addition, γ-secretase inhibitor (GSI) prevented cell proliferation and TNF-α-dependent invasion of OSCC cells in vitro. These results indicate that altered expression of Notch1 is associated with increased cancer progression and that Notch1 regulates the steps involved in cell metastasis in OSCC. Moreover, inactivating Notch signaling with GSI could therefore be a useful approach for treating patients with OSCC.

Relationship between microRNA expression levels and histopathological features of dysplasia in oral leukoplakia

BACKGROUND

Increased expression of microRNAs (miRNAs), miR-21, miR-345, and miR-181b has been demonstrated in oral leukoplakia (OL) that progresses to oral squamous cell carcinoma (OSCC), suggesting a miRNA signature with potential prognostic value. On the basis of these findings, this pilot study aimed to investigate the cytological and histopathological features that are used to grade oral dysplasia and determine associations with the expression of these 3 potentially cancer-related miRNAs. We also compared the expression levels of these miRNAs in OL with normal oral mucosa and OSCC.

METHODS

We evaluated miRNA expression by qPCR in 22 samples of OL demonstrating different grades of dysplasia, as well as 17 cases of OSCC, and 6 samples of normal oral mucosa. We associated the miRNAs expression profiles with cytological and histopathological features of OL.

RESULTS

OSCC cases showed increased expression of all 3 miRNAs when compared with OL and normal oral mucosa. Increased expression of miR-21 was also observed in OL when compared with normal oral mucosa. We found a higher expression of miR-21 and miR-181b in OL that presented with an increased number of mitotic figures, increased nuclear/cytoplasmic ratio, or hyperchromasia. Increased expression of miR-21 was also detected in OL with abnormally superficial mitosis. Higher expression of miR-345 was observed in OL with an increased number and size of nucleoli or increased nuclear/cytoplasmic ratio.

CONCLUSIONS

In conclusion, the present study shows that some cytological and histopathological parameters used to grade dysplasia are associated with altered miRNA expression.

Oral squamous cell carcinoma in relation to field precancerisation: pathobiology

Squamous cell carcinoma of the oral cavity evolves within a field of precancerized oral epithelium containing keratinocytes at different stages of transformation. Following acquisition of additional genetic alterations, these precancerous keratinocytes may become cancerous.Persons with apparently successfully treated oral squamous cell carcinoma are at high risk of developing a new carcinoma at, or close to the site of the treated tumour. This second carcinoma may have developed either from malignant keratinocytes left behind at surgery (recurrence), or from transformed keratinocytes within the field of precancerized epithelium from which the primary carcinoma had arisen (new carcinoma).The cells of the new carcinoma may have genetic changes in common with the cells of the original carcinoma because both are descended from a proliferating monoclone within the precancerized field; but if the new cancer originates from a different clone, it may have a dissimilar genetic profile even if the original and the new carcinoma are closely contiguous.The purpose of this article is to review the pathobiology of oral squamous cell carcinoma in relation to fields of precancerised oral epithelium.

An Insight to Oral Epithelial Dysplasia

Oral dysplasia is a potentially precancerous lesion diagnosed histologically. While the risk of progression is associated with histological grade, it is currently impossible to predict accurately which lesions will progress. Although most oral pathologists recognize and accept the criteria for grading epithelial dysplasia based on architectural and cytological changes, there can be considerable interexaminer and intraexaminer variation in the assessment of the presence or absence and the grade of oral epithelial dysplasia. This article reviews the alterations, criteria, different grading systems and the markers used for assessing the malignant transformation of epithelial dysplasia.

How to cite this article

Rastogi V, Puri N, Mishra S, Arora S, Kaur G, Yadav L. An Insight to Oral Epithelial Dysplasia. Int J Head Neck Surg 2013;4(2):74-82.

How should we manage oral leukoplakia?

The aim of this article is to review the management of oral leukoplakia. The topics of interest are clinical diagnosis, methods of management and their outcome, factors associated with malignant transformation, prognosis, and clinical follow-up. Global prevalence is estimated to range from 0.5 to 3.4%. The point prevalence is estimated to be 2.6% (95% CI 1.72-2.74) with a reported rate of malignant transformation ranging from 0.13 to 17.5%. Incisional biopsy with scalpel and histopathological examination of the suspicious tissue is still the gold standard for diagnosis. A number of factors such as age, type of lesion, site and size, dysplasia, and DNA content have been associated with increased risk of malignant transformation, but no single reliable biomarker has been shown to be predictive. Various non-surgical and surgical treatments have been reported, but currently there is no consensus on the most appropriate one. Randomised controlled trials for non-surgical treatment show no evidence of effective prevention of malignant transformation and recurrence. Conventional surgery has its own limitations with respect to the size and site of the lesion but laser surgery has shown some encouraging results. There is no universal consensus on the duration or interval of follow-up of patients with the condition.

Reproducibility of grading systems in oral epithelial dysplasia

Objective: To assess inter and intra observer variability in grading oral epithelial dysplasia (OED) using Smith and Pindborg grading system, WHO classification system and Brothwell DJ et al. classification system. Study design: In the study 45 histological tissues of dysplasia, 15 each of mild, moderate and severe dysplasia were coded and blindly graded by three observers in three grading systems. Further on the same observers graded 15 slides again of the previous 45 for analyzing the reproducibility in the three grading systems. The individual significance of various indicators of dysplasia among various grades of dysplasia was also assessed. Result: Inter observer agreement was significantly higher in Brothwell system as compared to WHO and Smith and Pindborg system. Intra observer agreement was significantly higher in Smith and Pindborg system, but the predictability and the probability index was distributed over a larger range in this system. Each indicator of dysplasia was also found to be statistically significant (P<0.05) for grading dysplasia. Conclusion: The present study puts forth the inherent intricacies in the grading of oral premalignant lesions.

Key words:Carcinoma, dysplasia, grading systems, reproducibility.

Alterations in the immunoexpression of galectins-1, -3 and -7 between different grades of oral epithelial dysplasia

INTRODUCTION

Oral epithelial dysplasia (OED) is a potentially malignant lesion characterized by a combination of cytological and architectural anomalies, which are essential for its diagnosis. Galectins are proteins that participate in cell cycle, adhesion and differentiation, apoptosis, and immune responses, as well as in cancer development and progression.

MATERIALS AND METHODS

The aim of this study was to analyze the immunohistochemical expression of galectins-1, -3, and -7 in the OED (21 low risk and 29 high risk) and normal oral mucosa (NOM). The binary grading system was used.

RESULTS

Galectin-1 was expressed in the middle/lower third in most OED cases. Nuclear/cytoplasmic staining was observed in most low-risk and high-risk OEDs. All cases of NOM were negative for galectin-1. Galectin-3 was expressed in the middle/lower third in most low-risk cases. Nuclear/cytoplasmic staining was noted in most low-risk and high-risk OEDs. Middle/lower third and in membrane staining was detected in four cases of NOM for galectin-3. Galectin-7 was expressed in the upper/middle third in most of OED cases. Nuclear/cytoplasmic staining predominated in low-risk and high-risk OEDs. Galectin-7 was detected in four cases of NOM, all of them presenting staining in the upper/middle third and in the membrane.

CONCLUSION

The differences in the immunoexpression of galactin-1, -3, and -7 between different grades of OEDs suggest the involvement of this protein in the progression of dysplasias.

Oral Leukoplakia as It Relates to HPV Infection: A Review

Leukoplakia is the most common potentially malignant lesion of the oral cavity and can be categorised according to its clinical appearance as homogeneous or nonhomogenous. Tobacco and areca nut use, either alone or in combination are the most common risk factors for oral leukoplakia, but some oral leukoplakias are idiopathic. Some leukoplakias arise within fields of precancerized oral epithelium in which the keratinocytes may be at different stages of cytogenetic transformation. Leukoplakias may unpredictably regress, may remain stable, or may progress to carcinoma. There is a greater risk of carcinomatous transformation of idiopathic leukoplakia, of non-homogenous leukoplakia, of leukoplakia affecting the floor of the mouth; the ventrolateral surface of the tongue and the maxillary retromolar and adjoining soft palate (collectively called high-risk sites), of leukoplakia with high-grade epithelial dysplasia, and of leukoplakia in which the keratinocytes carry cytogenetic alterations associated with carcinomatous transformation. Although there appears to be some link between human papillomavirus (HPV) and oral leukoplakia, there is little evidence to support a causal relationship either between HPV infection and oral leukoplakia or between HPV-infected leukoplakic keratinocytes and their carcinomatous transformation.

Cell transformation and the evolution of a field of precancerization as it relates to oral leukoplakia

Potentially malignant oral leukoplakias arise within precancerized epithelial fields consisting of cytogenetically altered keratinocytes at various stages of transformation. The evolution of a clone of keratinocytes culminating in a precancerous phenotype is a function of the number of mutagenic events, rather than the sequential order in which they occur. The altered molecular configurations of the transformed precancerous keratinocytes may confer upon them a growth advantage in relation to the unaltered neighbouring keratinocytes. Replicative clonal expansion of these keratinocytes results in the progressive replacement of the surrounding normal keratinocytes by the fitter clone or clones of altered cells. The precancerized oral epithelial field may have a clinically normal appearance and microscopically may be normal or may show dysplasia. Oral leukoplakias arising within a precancerized epithelial field in which the keratinocytes show DNA aneuploidy or loss of heterozygosity at certain specific chromosomal loci have the potential to progress to carcinoma. The pathogenic mechanisms that drive the carcinomatous transformation of oral leukoplakias, in which cytogenetic alterations in the keratinocytes cannot be detected, are unknown.

Er,CR:YSGG lasers induce fewer dysplastic-like epithelial artefacts than CO2 lasers: an in vivo experimental study on oral mucosa

Our aim was to assess wounds made by lasers (CO(2) and Er,Cr:YSGG) for their epithelial architectural changes and width of damage. We allocated 60 Sprague-Dawley(®) rats into groups: glossectomy by CO(2) laser at 3 different wattages (n=10 in each); glossectomy by Er,Cr:YSGG laser at two different emissions (n=10 in each), and a control group (n=10). Histological examination assessed both prevalence and site of thermal artefacts for each group. Both lasers (CO(2) and Er,Cr:YSGG) caused the same type of cytological artefacts. The 3W Er,Cr:YSGG laser produced the fewest cytological artefacts/specimen, and was significantly different from the other experimental groups: 3W CO(2) laser (95% CI=0.8 to 1.0); the 6W CO(2) laser (95% CI=0.1 to 2.0) and the 10W CO(2) laser (95% CI=1.1 to 3.0). CO(2) lasers (3-10W) generate epithelial damage that can simulate dysplastic changes with cytological atypia that affects mainly the basal and suprabasal layers. Irradiation with Er,CR:YSGG laser (2-4W) produces significantly fewer cellular artefacts and less epithelial damage, which may be potentially useful for biopsy of oral mucosa.

Morphometry of the basal cell layer of oral leukoplakia and oral squamous cell carcinoma using computer-aided image analysis

Objectives:

To study and compare the changes in nuclear and cellular size, shape and nuclear–cytoplasmic ratio of the cells in the basal layer of oral leukoplakia and well-differentiated oral squamous cell carcinoma (SCC) with normal buccal mucosa, using computer-aided image analysis in tissue sections.

Study design:

This was a retrospective study conducted on tissue sections on a total number of 70 cases to determine the various morphometric parameters. The data collected in this study were analyzed statistically by computing descriptive statistics, viz., percentage, mean, standard deviation, standard error of mean, 95% confidence interval for mean. The difference in the control and study groups for various diagnostic variables was compared by means of analysis of variance (ANOVA), Student’s t-test for independent samples, wherever applicable. Mann–Whitney U-test and Kruskal–Wallis test were used where the data were found to be asymmetrical and the standard deviations were also different. The results were considered statistically significant whenever P ≤ 0.05.

Results:

Our results were significant for the morphometric parameter, size. The values of nuclear perimeter and area, cellular perimeter and area increased gradually from the normal buccal mucosa to leukoplakia, reaching the highest value in SCC. There was statistically significant difference in the nuclear and cellular areas to differentiate between leukoplakia and squamous cell carcinoma. Two variables which were used to study the shape, “form perimeter (PE)” and “contour index (CI)”, showed significant difference between normal buccal mucosa and leukoplakia and between normal buccal mucosa and SCC. The morphometric parameter, nuclear–cytoplasmic ratio, in our results showed an increase in leukoplakia and SCC compared to normal buccal mucosa, but the difference was not significant between leukoplakia and SCC.

Conclusion:

The morphometric parameter, size, was useful to differentiate between normal, potentially malignant leukoplakia and SCC.

Nucleostemin affects the proliferation but not differentiation of oral squamous cell carcinoma cells

Nucleostemin (NS) has been reported as essential for stem and cancer cell proliferation. To investigate the significance of NS in oral squamous cell carcinomas (OSCCs), we examined NS expression in neoplastic tissue of the tongue and in OSCC cell lines. Nucleostemin expression in the histological samples showed positive correlation with Ki-67 expression. Furthermore, NS expression was associated with cellular proliferation in OSCC cell lines using siRNA, which upregulated p27, a cyclin-dependent kinase inhibitor. Regarding OSCC differentiation, NS expression did not influence cornification or oral epithelial differentiation markers such as involucrin and cytokeratin19. Thus, NS is widely expressed in normal and neoplastic oral epithelial tissues, and is likely a marker of proliferation.

Oral premalignant lesions: from the pathological viewpoint

Under the widely used World Health Organization (WHO) classification for the pathological diagnosis of oral premalignant lesions, dysplasia, which is graded as mild, moderate or severe, and carcinoma in situ (CIS), which is a non-invasive carcinoma, are classified as precursor lesions of oral squamous cell carcinoma. Since the first edition (Wahi et al. International histological classification of tumours no. 4, WHO, Geneva, 1971), the criterion for CIS--that all epithelial layers are replaced by atypical cells--has remained unchanged. However, this dysplasia-carcinoma sequence theory was introduced from the viewpoint of pathological changes in the uterine cervix: in contrast, almost all premalignant lesions and CIS of the oral mucosa show superficial maturation and differentiation. Based on this recognition, the squamous intraepithelial neoplasia (SIN) classification and Ljubljana classification were included in WHO's latest edition published in 2005. Although the WHO classification is commonly used in Japan, recent developments in oral oncology have promoted modifications of the classification used in this country. In 2005, the Working Group of the Japan Society for Oral Tumours advocated iodine staining and proposed a modified SIN system, and in 2007, the Working Committee of the Japanese Society for Oral Pathology (JSOP) reported a new CIS (JSOP) definition that included differentiated-type CIS. In 2010, based on these studies, a new entity--oral intraepithelial neoplasia (OIN)--was included in the first edition of General Rules for Clinical and Pathological Studies on Oral Cancer. In this review, we focus on the OIN/CIS (JSOP) new classification of premalignant lesions in oral mucosa, which further advances the concept of SIN.

Rigid confocal endoscopy for in vivo imaging of experimental oral squamous intra-epithelial lesions

BACKGROUND

A rigid confocal endoscope has been developed to assess the oral squamous epithelium of mice and to determine sensitivity, specificity, and accuracy of this new technology.

METHODS

This endoscope is connected to the commercially available Heidelberg Retina Tomograph (HRT). HRT is a device with a 670-nm diode laser designed to acquire topographical measurements of the optic nerve head. Real-time rigid confocal endoscopy is demonstrated by imaging the epithelial lesions of a mice model. Six-week-old male C57Bl/6 mice were randomly divided into a non-treated group (n = 10) and into a 4-nitroquinoline 1-oxide (4-NQO)-treated group (n = 50). In the 4-NQO-treated group, the mice obtained 4-nitroquinoline 1-oxide in the drinking water (100 microg/ml) to induce tumourigenesis in the mouse tongue. The 4-NQO-solution was diluted in the drinking water for mice. After an 8-16-week carcinogen treatment with 4-NQO (ad libitum), mouse tongues were dissected within 3 h after CO(2) overdose. After confocal microscopy of all lesions of the tongue, conventional histopathological investigation was performed.

RESULTS

The inter-rater reliability for the two observers of the confocal microscopic findings was found to be Kappa = 0.59 (P < 0.001). The penetration depth varied in the healthy tissue of the underside of the tongue throughout this study and was measured between 104 and 240 microm. In keratotic lesions, the penetration depths were diminished and varied between 80 and 140 microm. Strong keratinization inhibits the evaluation of the epithelium. For differentiation between low-grade and high-grade squamous intra-epithelial lesions, a sensitivity and specificity of 73% and 88% was reached.

CONCLUSIONS

The animal experiment with this non-invasive new technology indicates that this imaging technology facilitates the detection of pre-cancerous lesions of the underside of the oropharynx. Human studies on oropharyngeal and laryngeal lesions are needed to prove the applicability of this method in the field of otorhinolaryngology.