Oral leukoplakia. Current concepts in diagnosis, management, and malignant potential

Oral mucosal lesions - A study of 369 cases

Background

Diagnosing and treating oral cavity lesions is a challenging task for most of the clinicians due to similar symptoms and clinical appearances. Frequently, histopathology and immunohistochemistry aid in making the diagnosis.

Objectives

The objectives were to describe the clinical features, and histopathological features and systemic association in patients with oral mucosal lesions (OML).

Materials and Methods

A cross-sectional descriptive study was undertaken at a tertiary care centre in patients with OML. A total of 369 cases with OML were included in the study.

Results

Males constituted 61.78% of the cases. History of habits such as tobacco, gutka chewing, smoking, and alcohol was given by 32.25%, 29.81%, 26.56%, and 11.38% of cases, respectively. Common symptoms were soreness, burning sensation, oral pain and ulcers. Both oral and cutaneous involvement was seen in 17.89% of cases. Oral lichen planus (oral LP) constituted largest group of patients (21.96%) wherein reticulate type was the most frequent type and buccal mucosa was the commonest site. Oral carcinomas constituted 20.33% of cases followed by infective etiology (11.92%), vesiculobullous group of diseases (10.30%), aphthous stomatitis (8.94%), premalignant lesions (7.05%) such as leukoplakia (3.80%) and submucous fibrosis (2.44%). Histopathology was done in 209 cases. Clinico-histopathological correlation was seen in oral LP (90.27%), oral pemphigus (82.35%), and malignancies (98.66%).

Conclusion

Oral LP formed the largest group of cases followed by Oral squamous cell carcinoma (SCC). Several rare conditions, such as Melkersson-Rosenthal syndrome and blue rubber bleb nevus syndrome were also a part of the study. Thorough clinical and histopathological examination in this diverse group of diseases clinches the diagnosis.

Oral dermatological conditions: a clinical study

Oral cavity consists of a small vestibule and a larger oral cavity proper. A wide number of dermatological conditions can affect the oral cavity. The clinical characteristics of the same were studied in patients attending departments of Dermatology/ENT Himalayan Institute of Medical Sciences, Dehradun. To delineate and identify the various patterns of oral dermatological conditions in this part of the country. One hundred and fifty patients were included in the study having oral lesions irrespective of age, sex and duration. Clinical examination including cutaneous examination and simple investigations like routine blood, urine, stool, blood sugar, KOH mount and scraping, Tzanck test, and on certain cases biopsy were carried out. Out of 11,840 patients attending Dermatology/ENT OPD, HIMS, Dehradun from April 2008 to March 2009, 150 patients were having various disorders with oral manifestations. The incidence of oral cavity dermatoses in this study was 1.26%, male to female ratio was 2:3. (Out of 150 patients, 60 were males and 90 were females). Aphthous ulcer (28.57%) and pemphigus vulgaris (26.60%) formed the major bulk of patients followed by SLE (17.02%), oral candidiasis (16.07%), DLE (13.83%), lichen planus (12.77%) and others.

A high prevalence of p53 mutations in pre-malignant oral erythroplakia

Oral squamous-cell carcinoma is thought to be preceded by a number of precursor stages which induce morphological changes in cells of the oral mucosa resulting in clinically detectable pre-malignant lesions such as erythroplakia or leukoplakia. To better understand the etiology of oral erythroplakia, we have examined the p53 tumor-suppressor gene (exons 5-9) for mutations in 24 oral erythroplakia lesions of varying dysplastic phenotypes by PCR/single-strand conformational polymorphism and direct DNA-sequencing analyses. A total of 12 p53 mutations were detected in 11 of 24 (46%) erythroplakia specimens (one specimen contained two different p53 mutations); 25% were single-base-pair deletions and 33% were either G:C-->T:A transversions or G:C-->A:T transitions. A high prevalence of p53 mutation was observed in all categories of erythroplakia lesions: 33% for mildly dysplastic lesions, 50% for lesions exhibiting moderate to severe dysplasia and 50% for lesions that were carcinoma in situ. Although the combined prevalence of p53 mutations observed in erythroplakia was significantly higher (p = 0.02) than that observed earlier for leukoplakia, the prevalence of p53 mutations was similar in erythroplakia and leukoplakia specimens from smokers. The prevalence and spectrum of p53 mutations observed in this series of erythroplakia lesions are similar to those observed for oral squamous-cell carcinoma. These results indicate that mutations of the p53 gene may be linked to the high malignant potential of erythroplakia and provide further evidence that p53 mutation may be an early event in the genesis of oral squamous-cell carcinoma.

Cutaneous manifestations and consequences of smoking

Cigarette smoking is strongly linked to serious internal diseases such as cancer, cardiovascular disease, and lung disease. However, the external manifestations and consequences of smoking are relatively unknown. Although generally less ominous, the cutaneous manifestations of smoking may be associated with significant morbidity. This article reviews the known adverse effects on the skin of smoking.

A low incidence of p53 mutations in pre-malignant lesions of the oral cavity from non-tobacco users

To determine the incidence of p53 mutations in pre-malignant lesions of the oral cavity from individuals without prior history of tobacco use, we have analyzed the conserved regions of the p53 gene (exons 5-9) in archival oral cavity lesion specimens obtained from patients with varied tobacco use histories, by polymerase chain reaction/single strand conformational polymorphism (PCR/SSCP) and DNA sequencing analysis. Twenty-six lesions were analyzed from 14 patients, with multiple lesions obtained from 8 patients. Six of these patients used tobacco, (3 being cigarette smokers, 1 ex-cigarette smoker, 1 moderate cigar smoker and 1 snuff chewer). The remaining 8 patients had no prior history of tobacco use. Thirteen of the pre-malignant lesions exhibited severe dysplasia, 9 exhibited moderate dysplasia and 4 exhibited mild dysplasia. Four of the 26 lesions exhibited p53 mutations, each being from a tobacco user. None of the 13 lesions from never-tobacco users exhibited p53 mutations. There was a significantly higher p53 mutation incidence in pre-malignant lesions from tobacco users (including ex-smokers) than in non-tobacco users as well as in cigarette smokers plus snuff chewers than in non-tobacco users. Two of the mutations were observed in lesions exhibiting severe dysplasia: 1 in a lesion exhibiting moderate dysplasia and 1 in a lesion exhibiting mild dysplasia. These data suggest that p53 mutation may be a very early event in oral cavity tumor progression and demonstrate that pre-malignant lesions obtained from non-tobacco users do not exhibit p53 mutations.

Use of computer-assisted image analysis for noninvasive evaluation of oral lichenoid reactions and oral leukoplakia

The objective of the present study was to elaborate and to evaluate a method in which the clinical appearance of a mucosal lesion could be expressed by means of color and morphologic features extracted from digitized images. The ability to express mucosal changes with image features was evaluated, as was the accuracy of a classification of the lesions on the basis of image feature analysis. Computer-assisted image analysis was performed on digitized color slides from 76 patients with lichenoid reactions that included both oral lichen planus and contact lesions and 20 patients with homogenous oral leukoplakia. Color features were measured according to the intensity-hue-saturation color system, and morphologic features were estimated by tracing the hyperkeratotic area. Hyperkeratinizing and inflammatory tissue reactions could be demonstrated and defined by image analysis. Image features indicating inflammatory tissue reactions were more pronounced in cases of oral lichenoid reactions. Morphologic parameters could express the anatomic appearance of the lesions. The comparison between histopathologic diagnosis and a classification through computerized analysis demonstrated that 90.5% of oral lichenoid reactions could be separated from homogenous oral leukoplakia by linear discriminant analysis.

Oral precancer: preventive and medical approaches to management

Leukoplakias are among the most common potentially malignant oral lesions. Some are idiopathic, others are related to habits such as tobacco and/or alcohol use. Medical management includes reducing or abandoning these habits, increasing the intake of fruit and vegetables in the diet, and possibly the use of active agents. Retinoids, carotenoids and topical cytotoxic agents show promise, and newer therapies are on the horizon.