Epithelial dysplasia in oral lichen planus. A preliminary report of a Dutch-Hungarian study of 100 cases

Evaluation of the Altered Tissue Expression of HSP60 and HSP70 Genes in Oral and Cutaneous Lichen Planus Compared to Normal Healthy Tissues

Background:

Recent highlights have investigated the possible roles of molecular chaperons like heat shock proteins (HSPs) into Lichen Planus (LP)-onset and pathogenesis. This study for the first, determine the expression of both HSP60 and HSP70 genes in cutaneous LP (CLP) and oral LP (OLP) lesions compared to normal healthy cases and between different subtypes of OLP lesions by real-time (RT)-PCR.

Materials and Methods:

Paraffin blocks of LP lesions including 56 OLP and 56 CLP samples were selected from theMashhad University of Medical sciences, Mashhad, Iran. Also 56 biopsy samples of healthy normal participants were selected. The demographic and clinical characteristics were extracted from their medical records. The expression of HSP60 and HPS70 genes were evaluated using the real-time RT-PCR method.

Results:

The comparison of the expression of HSP60 and HSP70 genes among the patients with CLP and OLP showed a significant overexpression of HSP60 and HSP70 genes in both groups compared to the normal participants (P = 0.001). The expression of HSP60 and HSP70 genes was high in both the groups of CLP and OLP patients, but the amount was not significantly different between the two groups. Comparing the two mucosal subgroups of OLP lesions (non-erosive and erosive) showed that the expression of the HSP60 and HSP70 in erosive subtypes of OLP was significantly higher than the non-erosive subtypes of OLP (P = 0.001).

Conclusion:

Regarding the overexpression of HSP60 and HSP70 in the LP lesions compared to healthy biopsies, we conclude that HSP60 and HSP70 could have key roles in the etiopathogenesis of the OLP and CLP lesions. The overexpression of both HSP60 and HSP70 in the erosive OLP group compared to the non-erosive OLP group emphasized the possible roles of HSPs in the pathogenesis and premalignant changes of OLP lesions.

Dysplasia in oral lichen planus: relevance, controversies and challenges. A position paper

Background

Patients with oral lichen planus (OLP) have an increased risk of oral cancer. For this reason, OLP is classified as an oral potentially malignant disorder. However, the precise personal (or individual) risk is unknown. Recent meta-analytical studies have reported that dysplastic OLP may transform to cancer in around 6% of cases, while the rate of transformation is lower (<1.5%) in non-dysplastic cases. The presence of epithelial dysplasia has emerged as the most powerful indicator for assessing cancer risk in oral potentially malignant disorders in routine practice. However, the general acceptance of epithelial dysplasia as an accompanying histologic feature in OLP is subject to great controversy. Many pathologists consider the presence of dysplasia as a criterion to exclude OLP when routinely reporting on this disease. This practice, widespread among oral pathology professionals, has resulted in the underestimation of the potential for malignancy of OLP.

Material and Methods

A review of the literature was carried out in order to critically analyze the relevance, controversies and challenges encountered across the diagnosis of epithelial dysplasia in OLP.

Results

12 studies have been published examining dysplastic changes in OLP, reporting Figures ranging from 0.54% to 25% of cases with dysplasia in the first diagnostic biopsy. The diagnosis of dysplasia in the OLP poses an additional difficulty due to the fact that the affected oral epithelium per se develops changes related to autoimmune aggression. Among the most frequent histological features of OLP that develops dysplasia are basal cell hyperplasia with basaloid appearance, loss of basal cells polarity, cellular and nuclear pleomorphism and irregular stratification.

Conclusions

Epithelial dysplasia should not be considered an exclusion criterion for OLP; its evaluation requires experienced pathologists in this field.

Key words:Oral lichen planus, epithelial dysplasia, oral cancer.

[Precancerous lesions of the buccal epithelium]

Squamous cell carcinomas of the oral cavity and lips consistently have a high incidence (they constitute the fifth most common form of cancer in France) and carry a heavy prognosis, particularly if diagnosed late. According to different studies, between 10 and 80% of such carcinomas occur in a pre-existing or precancerous lesion. The World Health Organisation (WHO) recommends the use of two terms for such lesions: precursor lesions, i.e. histological lesions associated with intraepithelial neoplasia (IEN) and verrucous hyperplasia (VH), frequently resulting clinically in leukoplakia or erythroplakia; "at risk" lesions, which include lichen planus, submucosal oral fibrosis and certain forms of genodermatosis.

Expression of cytokeratins 10, 13, 14 and 19 in oral lichen planus

OLP is a chronic inflammatory disease of unknown etiology that may develop into squamous-cell carcinoma. Cytokeratins, which are important components of the cytoskeleton, are excellent epithelial differentiation markers used to study neoplastic and inflammatory diseases. To study the profile of cytokeratins in OLP and their possible association with dysplastic alterations, monoclonal antibodies were used for cytokeratins 10, 13, 14 and 19, in 26 samples of OLP. The streptavidin-biotin technique was employed in paraffin-embedded tissue sections. Sample analysis revealed suprabasal expression of cytokeratin 10 in 16/17 samples, 14 of them with reduced expression; suprabasal expression of cytokeratin 13 in 18/23, 16 of them with delay; basal and suprabasal expression of cytokeratin 14 in all samples; and focal basal expression of cytokeratin 19 in 4/21. Expression of cytokeratins 10, 13 and 14 was altered in OLP lesions. The inflammatory process and hyperkeratosis or parakeratosis seem to have interfered with the expression of these CKs. Cytokeratin 19 was expressed in the lesions, in a pattern similar to that mentioned in the literature for the non-keratinized oral mucosa. The presence of mild dysplasia did not change the expression of the cytokeratins studied. No differences in pattern of expression were observed between keratinized and non-keratinized areas in the lesions caused by OLP.

Oral lichen planus: controversies surrounding malignant transformation

Studies of the malignant potential of oral lichen planus (OLP) have been hampered by inconsistencies in the diagnostic criteria used for OLP, the criteria adopted to identify a true case of malignant transformation in OLP, the risk factors for malignant transformation and the optimum management of patients to ensure the early diagnosis of transformation. Consensus remains elusive, and leading workers in this field have recently published conflicting reports on the malignant potential of OLP and on the important question of the advisability of excluding patients with epithelial dysplasia or a tobacco habit from studies on this issue. The present review outlines these debates and proposes a possible a molecular basis for the malignant transformation in this disease.

Oral lichen planus: progress in understanding its malignant potential and the implications for clinical management

Oral lichen planus (OLP) is an inflammatory lesion that has malignant potential, but few cases of OLP progress to malignancy. A diagnosis of OLP should be confirmed on the basis of historical, clinical, and histologic data. The presence of dysplasia in an OLP-like lesion increases the risk of malignant transformation, mandating management and close follow-up. A molecular assessment of OLP may provide the best evidence of malignant risk and will likely become available for clinical use. In addition, exfoliated cells may be examined for loss of heterozygosity and may become a valuable clinical tool for patient follow-up. The treatment of OLP should include elimination of tissue irritants and recurring exposure to oral carcinogens. If OLP is symptomatic, appropriate treatment with immunosuppressive medications, particularly corticosteroids, should be undertaken. For lesions with dysplastic changes, management may include attention directed to the inflammatory change and follow-up biopsies to assess residual histologic changes that may represent dysplasia. Dysplastic OLP may be best treated as other oral dysplastic conditions; thus, regular, more frequent follow-up is required.

Management of oral lichen planus

Lichen planus is a relatively common disorder of the stratified squamous epithelia. Most dental and medical practitioners see patients with lichen planus, but not all are recognized as having the disease. Patients with lichen planus may have concomitant involvement of the disease in multiple sites. Oral lichen planus lesions usually have a distinctive clinical morphology and characteristic distribution, but oral lichen planus may also present a confusing array of patterns and forms, and other disorders may clinically mimic oral lichen planus. The etiopathogenesis of lichen planus appears to be complex, with interactions between genetic, environmental, and lifestyle factors. Much has now been clarified about the etiopathogenic mechanisms involved and interesting new associations, such as with liver disease, have emerged. The management of lichen planus is still not totally satisfactory in all cases and there is as yet no definitive treatment that results in long term remission, but there have been advances in the control of the condition. Amongst the many treatments available, high potency topical corticosteroids remain the most reliably effective, though topical cyclosporine, topical tacrolimus, or systemic corticosteroids may be indicated in patients whose condition is unresponsive to topical corticosteroids.

High frequency of allelic loss in dysplastic lichenoid lesions

Oral lichen planus (OLP) is a common mucosal condition that is considered premalignant by some, whereas others argue that only lichenoid lesions with epithelial dysplasia are at risk of progressing into oral carcinoma. A recent study from this laboratory used microsatellite analysis to evaluate OLP for loss of heterozygosity (LOH) at loci on three chromosomal arms (3p, 9p, and 17p) (Am J Path 1997;Vol151:Page323-Page327). Loss on these arms is a common event in oral epithelial dysplasia and has been associated with risk of progression of oral leukoplakia to cancer. The data showed that, although dysplastic epithelium demonstrated a high frequency of LOH (40% for mild dysplasia), a significantly lower frequency of LOH was noted in OLP (6%), which is even lower than that in hyperplasia (14%). Such results do not support OLP as a lesion at risk for malignant transformation. As a second step of the research, we determined LOH frequencies in 61 dysplastic lichenoid lesions (mild 35; moderate 19; severe 7) using the same microsatellite markers and compared these results with data obtained from the first study and from 13 normal mucosal specimens. Dysplastic lichenoid lesions showed a high frequency of loss (54% for lichenoid lesions with mild dysplasia), but values did not differ significantly from those observed in dysplasia of similar degree without lichenoid appearance. None of the normal mucosa demonstrated LOH. Epithelial dysplasia is a sign of malignant risk, independent of lichenoid changes. Such results suggest that pathologists should search for dysplasia carefully in lesions that otherwise qualify as OLP and that caution should be used when discounting dysplasia as being merely a reactive condition in lichenoid lesions.

The possible association between oral lichen planus and oral squamous cell carcinoma: a clinical evaluation on 14 cases and a review of the literature

Between 1986 and 1996, 263 patients, 156 females and 107 males, affected by oral lichen planus (OLP), were followed at the Division of Oral Medicine and Pathology, University of Naples 'Federico II', Italy, and at the Institute of Dentistry and Maxillofacial Surgery, University of Bari, Italy. During this follow-up, the possible association of OLP with oral squamous cell carcinoma (SCC), together with the possible association of OLP, oral SCC and chronic HCV-hepatitis, were investigated. 14 cases (5.32%) were known to have developed oral SCC: 10 (3.8%) in an area of pre-existing OLP, 3 (1.14%) in other sites, in 1 case the diagnosis of OLP and SCC was synchronous (0.38%). 3 patients were positive for anti-HCV antibody. Many carcinomas were in areas of reticular/plaque OLP. 3 patients had multiple simultaneous sites of oral involvement (21.42%); 5 patients developed oral SCC in different sites during the follow-up period (35.71%). These data, together with a clear histological evidence of progression to carcinoma within OLP lesions, suggest the probability of some cases of at least OLP having an intrinsic property predisposing to neoplastic transformation, confirming previous studies. For these reasons, the authors think that it is necessary to follow-up the patients regularly at least annually and possibly for life for the early diagnosis of a possible neoplastic degeneration. These consideration are particularly important in the case of atrophic or erosive OLP, and plaque OLP, especially when involving the dorsum of tongue.

Telomerase activity in oral lichen planus

The purpose of this study was to determine the expression of telomerase in refractory oral lichen planus. Using a polymerase chain reaction-based telomerase activity assay, we investigated telomerase activity in 20 oral lichen planus specimens (erosive 9, atrophic 11). Telomerase activity was detected in 14 cases (erosive 7, atrophic 7). Furthermore, 13 cases of lichen planus with mild dysplasia proved telomerase-positive in eight specimens and six of seven cases devoid of dysplasia were also positive in the telomerase assay. The data indicate that, in general, telomerase activity might be frequently detectable in OLP. The data also suggest that telomerase activity might not be particularly associated with the premalignant phenotype in OLP.

Update on oral lichen planus: etiopathogenesis and management

Lichen planus (LP) is a relatively common disorder of the stratified squamous epithelia, which is, in many ways, an enigma. This paper is the consensus outcome of a workshop held in Switzerland in 1995, involving a selection of clinicians and scientists with an interest in the condition and its management. The oral (OLP) eruptions usually have a distinct clinical morphology and characteristic distribution, but OLP may also present a confusing array of patterns and forms, and other disorders may clinically simulate OLP. Lesions may affect other mucosae and/or skin. Lichen planus is probably of multifactorial origin, sometimes induced by drugs or dental materials, often idiopathic, and with an immunopathogenesis involving T-cells in particular. The etiopathogenesis appears to be complex, with interactions between and among genetic, environmental, and lifestyle factors, but much has now been clarified about the mechanisms involved, and interesting new associations, such as with liver disease, have emerged. The management of lichen planus is still not totally satisfactory, and there is as yet no definitive treatment, but there have been advances in the control of the condition. There is no curative treatment available; immunomodulation, however, can control the condition. Based on the observed increased risk of malignant development, OLP patients should be offered regular follow-up examination from two to four times annually and asked to report any changes in their lesions and/or symptoms. Follow-up may be particularly important in patients with atrophic/ulcerative/erosive affections of the tongue, the gingiva, or the buccal mucosa. Much more research is required into the genetic and environmental aspects of lichen planus, into the premalignant potential, and into the possible associations with chronic liver, and other disorders. More clinical studies are required into the possible efficacy of immunomodulatory drugs such as pentoxifylline and thalidomide.

Quantitative cellular and nuclear volumetric alterations in epithelium from lichen planus lesions of human buccal mucosa

Patients with oral lichen planus lesions may represent a relatively high risk population for subsequent development of oral cancer. Little is known of the relative effects of chronic inflammation and the process of malignant transformation itself on the histological structure of transforming epithelia. We have assessed cellular and nuclear volumes in defined basal and spinous cells from normal buccal mucosa epithelium, from epithelium associated with a non-specific chronic inflammatory infiltrate and from lichen planus lesions. Normal (N) tissues were obtained from the margins of non-neoplastic buccal mucosa lesions. Inflammatory (INF) lesions were from areas of the buccal mucosa diagnosed clinically as traumatic irritation without ulceration, and lichen planus (LI) lesions were biopsied from areas exhibiting Wickham's striae. Basal and spinous epithelial cells from normal and pathological human buccal mucosa were measured on haematoxylin and eosin-stained sections imaged through a video camera using a Zeiss VIDAS analyser and from these measurements, nuclear (VN) and cellular (VCELL) volumes were determined. VN and VCELL derived for both basal and spinous strata were similar in N and INF groups but were almost doubled in the LI group. Comparisons between LI and all other groups were significantly elevated. The effects of the inflammatory infiltrate on the oral epithelium in lichen planus and in non-specific inflammation thus differ significantly. VN and VCELL may serve as potential discriminators between benign lesions and premalignant lichen planus.

Possible premalignant character of oral lichen planus. The Amsterdam experience

In the present paper the 21-yr experience of the Department of Oral and Maxillofacial Surgery and Oral Pathology, and the Department of Otorhinolaryngology of the Free University Hospital, Amsterdam, is reported with regard to the possible premalignant character of oral lichen planus. The study consists of two parts: 1) the follow-up of 113 patients with histopathologically proven oral lichen planus, and 2) a search for lichen planus in 727 patients who have been admitted for oral cancer. Three patients with histopathologically proven lichen planus developed a squamous cell carcinoma in an average follow-up period of 7 yr. In the 727 patients with oral cancer, two additional patients with the simultaneous occurrence of oral lichen planus were observed. Our experience gives some but not very strong support to the hypothesis that oral lichen planus is a premalignant condition.

White plaque of the dorsal tongue

A case of oral lichen planus has been discussed. The causes, associated conditions, laboratory tests, and treatment were addressed. The use of cyanoacrylate "super glue" may have acted as a contactant and promoted the patient's localized lichenoid process. No additional treatment was provided other than confirmation of clinical suspicions. The most important factor was ruling out the possibility of a dysplastic or a malignant process. Should the patient become symptomatic, the treatment would probably start out with kaolin and pectin (Kaopectate) lidocaine/benadryl rinses. Should supportive therapy fail, alternative regimens including topical to systemic corticosteroids would be considered.

Oral lichenoid dysplasia: a clinicopathologic analysis

Three women had a diagnosis of oral lichen planus (OLP), which was made on the basis of clinical and histologic features. All three had persistent burning pain associated with large mucosal lesions. Changes in the color (red, red and white, white), configuration, and severity of the lesions were unpredictable and did not correlate well with topical corticosteroid therapy. Only one patient used tobacco (cigarettes)--this patient had recurrent oral candidiasis and was receiving multiple medications. One of the two nonsmokers was a denture wearer with a single episode of candidiasis. After 63, 32, and 56 (mean 50) months, carcinoma developed in all three. In retrospect, the initial biopsy specimens of two patients exhibited lichenoid dysplasia, whereas that of the third showed only lichenoid mucositis. Although speckled erythroplakia was the earliest clinical sign of a classic, nonregressing premalignant lesion, it already signaled the presence of invasive carcinoma. Some early epithelial dysplasias appear to have a robust inflammatory/immunologic response to the antigenically (but as yet not histologically) altered dysplastic epithelium and a high probability of at least temporary resolution. Mucosal erythema of obscure origin displaying spontaneous, usually temporary, partial to complete regression may be common to both purely inflammatory conditions like lichen planus and early epithelial dysplasia. We contend that some, if not most, cases of apparent malignant transformation of OLP likely represent red and white lesions that were dysplastic from their inception but that mimic OLP both clinically and histologically.

Epithelial dysplasia of the oral cavity and lips

Between 1970 and 1986, 1651 biopsy specimens from the oral cavity or lips with a diagnosis of epithelial dysplasia were accessioned by the Medical College of Virginia Oral Pathology Diagnostic Service (Richmond, VA). Of the four histologic grades of epithelial dysplasia (focal mild, mild, moderate, and severe), most of the cases were diagnosed as mild (54.1%) and the fewest (8.1%) were in the severe category. The overall mean age at time of diagnosis was 56.7 years. A predilection for occurrence in males was confirmed, but a lower than expected incidence in blacks was noted. The most common anatomic sites were the buccal mucosa, palate, and floor of mouth. The anatomic areas which were most likely to have a severe epithelial dysplasia were the ventral surface of the tongue and the lip. Patients with dysplasias in more than one site had a slightly higher probability of being diagnosed as either moderate or severe. The cases associated with lichen planus usually were found on the buccal mucosa and demonstrated a shift toward a milder degree of dysplasia.

Subjectivity in evaluating oral epithelial dysplasia, carcinoma in situ and initial carcinoma

During the 2nd Meeting of the International Association of Oral Pathologists in Amsterdam (1984), an exercise was held to study subjectivity in evaluating oral epithelial dysplasia. A poster with 9 color photomicrographs was presented to be evaluated anonymously by the participants. A total of 72 submitted diagnostic suggestions. In Table 1 these suggestions are given together with the diagnosis by the authors. A surprisingly wide spectrum of diagnostic suggestions was found indicating the need for an internationally accepted set of criteria for oral epithelial dysplasia.