A review of the recent literature regarding malignant transformation of oral lichen planus

Oral lichen planus and malignant transformation: a longitudinal cohort study

OBJECTIVE

Oral lichen planus (OLP) is associated with risk for developing oral squamous cell carcinoma (OSCC). We performed a 7-year prospective study to assess the incidence of malignant transformation of OLP among adults.

STUDY DESIGN

Three hundred twenty-seven OLP patients, 229 women (70.0%) and 98 men (30.0%), were observed during the follow-up period.

RESULTS

During a mean follow-up of 81.7 months, 8 of 327 patients developed an OSCC in OLP areas (0.36%/y), yielding the high overall standardized incidence ratio of 17.7 (95% confidence interval [CI] 8.8-35.3). The standardized incidence ratio for OSCC was significantly higher in women [27.0 (95% CI 11.2-64.8)] than in men [11.2 (95% CI 3.6-34.9)]. Six OSCCs were well differentiated (75%) and 2 moderately differentiated (25%). Three subjects (37.5%) developed recurrences within 2 years (mean 16.1 ± 3.5 months). Disease-free survival rate after 69.8 months was 97.3%.

CONCLUSIONS

OLP was associated with a significant increase in the risk for OSCC. Close surveillance may help to reduce the morbidity of OSCC arising from OLP at 24 months.

Allelic imbalance in oral lichen planus and assessment of its classification as a premalignant condition

OLP is a relatively common immune-mediated mucosal condition with a predilection for middle-aged women. Although classified as a premalignant condition, this classification remains controversial. Using stringent diagnostic criteria, some authors have found that OLP patients are not at increased risk for oral SCC. Credible but limited genetic evidence also indicates that epithelial tissues from OLP patients diagnosed using stringent criteria differs from premalignant or malignant oral lesions but is similar to epithelium from benign oral lesions. To further investigate this genetic line of evidence, biopsy specimens diagnosed as fibroma, OLP, low-grade dysplasia, high-grade dysplasia, and SCC were retrieved from the archives of the Oral Pathology Consultants at the Ohio State University. Using laser capture microdissection, tissue of interest was captured from each case and DNA subsequently extracted. Fluorescently labeled PCR primers were used to amplify DNA at 3 tumor suppressor gene loci (3p14.2, 9p21, and 17p13) and evaluated for LOH or microsatellite instability (MSI). OLP was found to be significantly different from low-grade dysplasia, high-grade dysplasia, and SCC when LOH/MSI was found at more than 1 loci (P = .011, P = .032, P = .003), but not different from benign fibromas (P = .395). In agreement with previous studies, well-documented cases of OLP diagnosed using stringent criteria exhibit a genetic profile more similar to a benign or reactive process than a premalignant/malignant one. These findings do not support the classification of OLP as a premalignant condition.

Pathophysiology, etiologic factors, and clinical management of oral lichen planus, part I: facts and controversies

Lichen planus (LP) is an inflammatory disease of the stratified squamous epithelia of unknown etiology. LP affects most frequently the oral mucosa, but it may also involve other mucosa and the skin. Oral LP (OLP) most frequently affects woman aged between 30 and 60 years. Histopathologic examination typically shows orthokeratotic hyperkeratosis, basal cell degeneration, and a dense well-defined infiltrate of lymphocytes in the superficial dermis. OLP lesions may result from the induction of keratinocytes apoptosis by cytotoxic CD8+ T cells stimulated by a yet unidentified self-antigen on a genetically predisposed patient. The association of OLP with hepatitis C virus (HCV) has been more consistently demonstrated in the Mediterranean area. Although HCV RNA and HCV-specific CD4+ and CD8+ T cells have been retrieved in the mucosal lesions of patients with chronic HCV infection and OLP, the eventual pathophysiology of HCV in OLP lesions remains unclear. Available treatments of OLP are not curative, and many have potentially prominent side effects. The objectives of OLP management should be to prevent and screen for malignant transformation and alleviate symptoms on the long-term. Avoidance of potential precipitating drugs, tobacco, alcohol, and local trauma, as well as strict oral hygiene, is essential. The first-line pharmacologic treatment relies on topical steroids. Systemic steroids should be limited to the short-term cure of severe refractory OLP. Life-long clinical follow-up, at least annually, is fundamental.

HPA-suppressive effects of aqueous clobetasol propionate in the treatment of patients with oral lichen planus

BACKGROUND

Oral topical corticosteroids have potential to produce inhibition of the hypothalamus-pituitary-adrenal (HPA) axis.

OBJECTIVE

To assess whether clobetasol propionate (CP) in aqueous solution causes HPA inhibition.

PATIENTS AND METHODS

Sixty-two patients with oral lichen planus or oral lichenoid lesions presenting with severe lesions were treated with topical oral 0.05% CP plus 100,000 IU/cm(3) nystatin in aqueous solution. Initial treatment of three 5-min mouthwashes (10 mL) daily was reduced, when the response was deemed complete or excellent, to a maintenance treatment of one 5-min mouthwash on alternate days for 6 months; treatment was then withdrawn and patients were followed up for 1 year. HPA function was assessed by plasma cortisol measurement and adrenocorticotropin (ACTH) stimulation at the end of the initial and maintenance treatment regimens.

RESULTS

The HPA axis was more frequently inhibited during initial (53/62; 85.5%) vs. maintenance (2/49; 4%) regimens of aqueous CP.

LIMITATIONS

In patients with morning plasma cortisol levels between 3 and 18 microg/dL, a normal result for the ACTH stimulation test only moderately reduces the possibility that a patient has secondary adrenal insufficiency. This can be considered a minor limitation in our study, as only three patients required additional assessment with the ACTH stimulation test.

CONCLUSIONS

Hypothalamus-pituitary-adrenal inhibition is substantial during initial treatment with aqueous CP three times daily.

Oral lichen planus versus epithelial dysplasia: difficulties in diagnosis

Histopathological diagnosis of oral lichen planus is not easy since some cases of epithelial dysplasia may present traits which are very similar to those from lichen planus.

Aim

to compare cell alterations which suggest malignancy present in oral lichen planus with those from epithelial dysplasia.

Material and methods

histological cross-sections of oral lichen planus and dysplasia, dyed by hematoxylin-eosin, were analyzed by means of light microscopy.

Results

variance analysis (alpha=5%) revealed a statistically significant difference between the average number of cell alterations in the lichen planus (5.83±1.61) and epithelial dysplasia (4.46±1.26). The chi-squared test did not show statistically significant differences between oral lichen planus and epithelial dysplasia in relation to the following cell alterations: increase in nucleus/cytoplasm ratio, nuclear hyperchromatism, irregular chromatin distribution and enlarged nuclei (p>0.05).

Conclusion

Some cell alterations which suggest malignancy present in the oral lichen planus may also be found in epithelial dysplasia, impairing its diagnosis and, consequently, stressing the importance of following these patients in the long run.

Results of patch testing in patients diagnosed with oral lichen planus

BACKGROUND

Oral lichenoid lesions (OLLs) resemble oral lichen planus (OLP) but develop secondary to various underlying causes. The role of contact allergy in precipitating and/or perpetuating OLL is well documented but remains controversial.

OBJECTIVE

To help elucidate the association of contact allergy and OLL, we reviewed patch-test readings in patients diagnosed with OLP-like lesions.

METHODS

We retrospectively reviewed patients diagnosed with OLP-like lesions who had patch tests performed between January 1, 2006, and December 31, 2007.

RESULTS

Patch tests were performed on 24 patients with a histopathologic and/or clinical diagnosis of OLP. Of these, 16 (67%) had positive patch-test readings. At least eight (50%) of these patients had clinically relevant reactions. Ten of the 16 patients (63%) had reactions to metals. In most of these patients, troublesome areas tended to localize adjacent to metallic dental restorations. Of the nine patients (56%) who had reactions to fragrances, flavorings, gallates, and/or diallyl disulfide, the majority improved after avoiding these allergens.

CONCLUSION

Our findings support the notion that contact allergy may underlie the pathogenesis of OLL and that allergen avoidance may result in amelioration of disease.

Chromosomal Numerical Aberrations in Oral Lichen Planus

The malignant potential of oral lichen planus (OLP) has been a matter of serious controversy. We aimed to detect chromosomal numerical aberrations in cells of brush samples collected from affected mucosa. The samples were simultaneously analyzed for morphology and fluorescent in situ hybridization (FISH) with chromosomes 2 and 8 centromeric probes. We analyzed 57 persons with OLP and 33 control individuals. A cut-off value of aneuploid cells was determined as 1.1%. Aneuploid cells were found in 16 persons with OLP (28.1%); in 10 individuals (17.5%), over 5% of the cells were aneuploid. Aneuploid cells were also detected in normal-looking mucosa of seven persons with OLP. One person with OLP developed squamous cell carcinoma; 10% of the cells examined were aneuploid. OLP carries an increased risk for chromosomal instability. Identifying aneuploid cells in a brush sample and the combined morphological and FISH analysis can increase the specificity in predicting the malignant potential of OLP.

Incidence and treatment outcome of oral lichen planus in Southeast Serbia in a 10-year period (1997-2007)

Background/Aim. Lichen planus is a chronic, immunologic, mucocutaneous disease with a wide range of clinical manifestations. The aim of this retrospective study was to evaluate the most common forms of oral lichen planus (OLP) and its symptoms and to describe treatment responses in patients during 10-year period. Methods. The study was conduced on 163 OLP patients who came in the Department of Oral medicine and Periodontology between 1997 and September 2007. Each case was classified into one of four clinical subtypes: reticular, atrophic, erosive-ulcerative, bullous. Results. There was no significant difference in patients age. Women were found to be significantly more likely to have OLP (p < 0.001). Corticosteroids were effective in reducing symptoms, erythema and healing ulcers. Improvement was shown over a long term in 61.35% patients. Over the long term 38.65% patients maintained the same type of OLP or it became a more severe type. Two patients (1.22%) developed oral carcinoma during the follow-up period. Conclusion. The response of patients with erosive OLP to a short course of systemic corticosteroids often was quite remarkable. However, symptoms and signs tended to recur after this treatment. Periodic examinations, patient education, medical treatment, monitoring of side-effects as well as follow-up biopsies are necessary for management of OLP patients.

Multiple masses on the tongue of a patient with generalized mucocutaneous lesions

Luca Pastore and colleagues discuss the differential diagnosis and management of a 62-year-old man who presented with a 6-cm fungating mass on the dorsum of the tongue.

Oral lichen planus and lichenoid reactions: etiopathogenesis, diagnosis, management and malignant transformation

Lichen planus, a chronic autoimmune, mucocutaneous disease affects the oral mucosa (oral lichen planus or OLP) besides the skin, genital mucosa, scalp and nails. An immune mediated pathogenesis is recognized in lichen planus although the exact etiology is unknown. The disease most commonly affects middle-aged females. Oral lichenoid reactions (OLR) which are considered variants of OLP, may be regarded as a disease by itself or as an exacerbation of an existing OLP, by the presence of medication (lichenoid drug reactions) or dental materials (contact hypersensitivity). OLP usually presents as white striations (Wickham's striae), white papules, white plaque, erythema, erosions or blisters. Diagnosis of OLP is established either by clinical examination only or by clinical examination with histopathologic confirmation. Direct immunofluorescence examination is only used as an adjunct to the above method of diagnosis and to rule out specific autoimmune diseases such as pemphigus and pemphigoid. Histopathologic features of OLP and OLR are similar with suggestions of certain discriminatory features by some authors. Topical corticosteroids are the treatment of choice for OLP although several other medications have been studied including retinoids, tacrolimus, cyclosporine and photodynamic therapy. Certain OLP undergo malignant transformation and the exact incidence and mechanisms are still controversial. In this paper, etiopathogenesis, diagnosis, management and malignant transformation of OLP and OLR have been reviewed.

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.

No differences in caspase-3 and Bax expression in atrophic-erosive vs. reticular oral lichen planus

BACKGROUND

Caspase-3 (CPP32) and Bax expression levels in oral lichen planus (OLP) lesions are considered reliable markers of apoptosis. The malignant transformation of OLP remains a very controversial matter. The objective of this study was to compare histological and apoptotic phenomena between atrophic-erosive and reticular forms of OLP.

METHODS

Analysis was conducted of biopsy samples from 18 patients with reticular and 14 with atrophic-erosive OLP. Conventional histology techniques were used to quantify histological markers of OLP and peroxidase/anti-peroxidase techniques to determine apoptosis markers caspase-3 (CPP32) and Bax.

RESULTS

More Civatte bodies and lymphocyte exocytosis were observed in atrophic-erosive than reticular OLP samples, without any statistical difference. No statistical significant differences in caspase-3 expression were found between these OLP forms in suprabasal layer (58.3% vs. 43.8%), basal layer (83.3% vs. 68.8%) or infiltrate (69.2% vs. 46.6%). Bax expression was relatively infrequent, and no differences were observed between atrophic-erosive and reticular forms.

CONCLUSIONS

The low frequency of apoptotic phenomena (caspase-3 and Bax) in epithelial cells of OLP may create a favourable substrate for malignant transformation. However, there does not seem to be an association with the clinical form (atrophic-erosive or reticular).

Oral mucosal disease: Lichen planus

Lichen planus (LP) is a common disorder in which auto-cytotoxic T lymphocytes trigger apoptosis of epithelial cells leading to chronic inflammation. Oral LP (OLP) can be a source of severe morbidity and has a small potential to be malignant. The diagnosis of OLP can be made from the clinical features if they are sufficiently characteristic, particularly if typical skin or other lesions are present, but biopsy is recommended to confirm the diagnosis and to exclude dysplasia and malignancy. OLP is treated with anti-inflammatory agents, mainly the topical corticosteroids, but newer agents and techniques are becoming available.

The possible premalignant character of oral lichen planus and oral lichenoid lesions: A prospective five-year follow-up study of 192 patients

Recently, we reported the preliminary results of a prospective study on the possible premalignant character of oral lichen planus (OLP) and oral lichenoid lesions (OLL). Based on these data it was concluded that there was some but no convincing support for the hypothesis that patients with OLL have an increased risk of development of oral cancer, but not so in patients with OLP. In the present treatise the results of prolonged follow-up of this cohort of patients have been described. A study group of 192 patients, 67 patients diagnosed with OLP and 125 patients with OLL, according to revised World Health Organization diagnostic criteria, was followed for periods ranging from 7.6 to 96.9 months (mean, 55.9 months). The expected number of patients with oral cancer in the group of patients with OLP and in the group of patients with OLL was estimated by comparing the number of patients, their ages, sex, and the length of follow-up to annual incidence rates of oral cancer for the general population in The Netherlands. The binomial test was used to determine whether the observed number of cases of cancer in the OLP group and the OLL group exceeded the expected numbers. Four out of 192 patients, two men and two women, developed a squamous cell carcinoma of the oral mucosa during follow-up. All malignant transformations occurred in the OLL group. The malignant transformation of the OLL group, based on a mean follow-up of 53.8 months, was calculated at 0.71% per year. A comparison of the expected against actual figures for the development of carcinomas revealed no increase in patients with OLP and a 142-fold increase in patients with OLL, the latter being statistically significant, with a p-value of 0.044. The present data give support to the hypothesis that patients with OLL have an increased risk of development of oral cancer. There seems to be no increased risk in patients with OLP. In view of our results we advise to monitor only the subgroup of OLL patients twice a year for early detection of possible malignant transformation.

Self-awareness of premalignant oral lesions among veterans attending six U.S. Veterans Affairs Medical Centers

Early identification is key to reducing the morbidity and mortality of oropharyngeal cancer. This study identified factors associated with self-awareness among patients newly diagnosed with a premalignant oral lesion. Data describing sociodemographics, medical/dental histories, tobacco/alcohol use and oral health were obtained by questionnaire and clinical examination of 73 veterans at six U.S. Veterans Affairs Medical Centers. Lesion types included homogenous and non-homogenous leukoplakia, smokeless tobacco lesion (STL), papilloma, lichen planus and erythroplakia. Prior to diagnosis, 29 subjects (39.7%) were unaware of their lesion. In bivariate analyses, lesion self-awareness was associated with anatomic location, multifocal/generalized appearance, pain, oral sores, and cigar use (p<0.05). Awareness varied with lesion diagnosis and was more likely with STL and less likely with homogenous leukoplakia (p<0.05). In multivariate analyses, awareness was predicted by the presence of a lesion on easily visible mucosa (adjusted odds ratio, OR=11.2) and a history of mouth sores (OR= 11.2). These findings identified marked variations in patient self-awareness of oral premalignant conditions.

DNA content, Cyclooxygenase-2 expression and loss of E-cadherin expression do not predict risk of malignant transformation in oral lichen planus

Oral lichen planus (OLP) may be associated with a small risk of malignant transformation of the oral mucosa. Using cases which had transformed, and those which had not, this study aimed to evaluate the potential of DNA content, expression of Cyclooxygenase-2 (Cox-2) and of epithelial (E)-cadherin as risk markers in lesions of OLP. We investigated 78 archival biopsies from; (1) 26 OLP patients with at least two biopsies, of whom seven presented OLP with epithelial dysplasia, followed by oral squamous cell carcinoma (OSCC) in five of them, (2) 19 OLP patients with one biopsy taken. Image cytometry for measurement of DNA content and immunohistochemistry for visualisation of Cox-2 and E-cadherin expression were performed. All OLP biopsies investigated were classified as diploid, one OLP with epithelial dysplasia was tetraploid and all OSCC were diploid. Cox-2 was detected in the epithelium of all OLP specimens investigated, as well as in epithelial dysplasias and OSCC. Focal loss of E-cadherin expression was observed in basal keratinocytes in 88% of the OLP specimens investigated, in all epithelial dysplasias and OSCC. In conclusion, neither aneuploidy, Cox-2 expression, nor loss of E-cadherin expression, were significant reliable markers to select OLP lesions at risk for development of OSCC in the present patient material.

Frequency of micronucleated exfoliated cells in oral lichen planus

OBJECTIVE

The purpose of this study was to determine the frequency of micronucleated exfoliated cells (MEC) in atrophic and erosive oral lichen planus (OLP).

MATERIALS AND METHODS

Twenty-two patients with atrophic and/or erosive OLP participated in this study. Lesions were scored ranging from 0 (no lesion) to 5 (large erosion) according to the severity and assessed for MEC. Exfoliated cells were obtained by swabbing the lesions and normal-appearing mucosa adjacent to the lesions. Swabbing was also performed in age-sex-matched normal individuals. Five hundred exfoliated cells were screened for nuclear anomalies including micronuclei, karyorhexis, pycnosis, and chromatid clumping.

RESULTS

The severity score of OLP ranged from 2 to 4 with the average of 2. The frequency of MEC in OLP patients was 3.79% and 0.37% in the lesions and normal-appearing mucosa, respectively. In normal individuals, the frequency of MEC was also 0.37%. Using a paired t-test, it was found that the MEC frequency in the OLP lesions was significantly elevated (p<0.01) as compared to that in normal-appearing mucosa adjacent to lesions and that in normal individuals. There were no statistically significant differences in the MEC frequency of the three severity scores as analyzed by Kruskal-Wallis one way analysis of variance on ranks (p>0.05).

CONCLUSION

This study revealed an increase in micronuclei in OLP lesions. The results indicate genotoxic damage in atrophic and erosive OLP.

Cell cycle regulating mechanisms in oral lichen planus: Molecular bases in epithelium predisposed to malignant transformation

OBJECTIVE

Expression of p53, p21, ki-67, Bcl-2 and caspase-3 proteins in oral lichen planus (OLP) was studied to investigate cell cycle regulation mechanisms in this disease.

MATERIAL AND METHODS

Oral biopsies were obtained from 51 patients with OLP and 26 controls for immunohistochemical analysis (peroxidase antiperoxidase) to quantify expression of the proteins under study (-: 0%, +: <10%, ++: 10-25%, +++: 26-50%, ++++: >50% positive cells).

RESULTS

Basal expression of caspase-3 was negative in 22 cases (46.8%) and positive in <10% of basal cells in 22 cases (46.8%); caspase-3 expression in inflammatory infiltrate was negative in 22 cases (46.8%) and positive in <10% of lymphocytes in 20 cases (42.5%). Basal expression of Bcl-2 was negative in 35 cases (74.5%); Bcl-2 was expressed in inflammatory infiltrate in 34 cases (72.3%) and was positive in <25% of lymphocytes in 14 of these (29.7%). Basal expression of p53 and p21 was positive in 32 (67.9%) and 23 (48.8%) cases, respectively. Basal expression of ki-67 was positive in 45 cases (95.7%), of which 20 (42.5%) showed positivity in >25% of cells; ki-67 was expressed in inflammatory infiltrate in 23 cases (48.9%). Significant associations were found between basal expressions of p53 and ki-67 (p<0.001) and between Bcl-2 expression in infiltrate and basal expression of ki-67 (p<0.001). No association was observed between basal expressions of p53 and caspase-3 (p=0.08). Bcl-2 expression in infiltrate and basal expression of ki-67 were independently associated with presence of OLP.

CONCLUSIONS

Epithelial cells in OLP do not preferentially develop apoptosis but rather cycle arrest or an increased proliferation rate, which may create a suitable substrate for malignant transformation.

Cytologic and DNA-cytometric examination of oral lesions in lichen planus

BACKGROUND

The aim of the present study was to evaluate the diagnostic value of exfoliative cytology (EC) and DNA image cytometry applied to oral lesions of lichen planus (LP; n = 56), in order to detect or exclude malignant transformation.

METHODS

Brush and excisional biopsies were obtained from 56 patients. In cases of oral LP in which brush biopsies were suspicious for tumor cells, nuclear DNA contents were measured, using a TV Image Analysis System.

RESULTS

In 50 patients EC yielded tumor cell-negative, doubtful in four cases and suspicious results obtained in two cases. DNA image cytometry revealed DNA-aneuploidy only in the two suspicious cases. The comparison between cytologic/DNA-cytometric diagnosis and biopsy histology resulted in a total agreement (LP without dysplasia: 54 and squamous cell carcinoma in LP: two cases).

CONCLUSIONS

In conclusion, cytology with DNA-cytometry is a highly sensitive, specific, and non-invasive method, which can be used for periodical follow up of oral LP lesions in order to early detect or exclude malignancy.

Current controversies in oral lichen planus: report of an international consensus meeting. Part 2. Clinical management and malignant transformation

Despite recent advances in understanding the immunopathogenesis of oral lichen planus (LP), the initial triggers of lesion formation and the essential pathogenic pathways are unknown. It is therefore not surprising that the clinical management of oral LP poses considerable difficulties to the dermatologist and the oral physician. A consensus meeting was held in France in March 2003 to discuss the most controversial aspects of oral LP. Part 1 of the meeting report focused on (1) the relationship between oral LP and viral infection, with special emphasis on hepatitis C virus (HCV), and (2) oral LP pathogenesis, in particular the immune mechanisms resulting in lymphocyte infiltration and keratinocyte apoptosis. Part 2 focuses on patient management and therapeutic approaches and includes discussion on malignant transformation of oral LP.

Number V Oral lichen planus: clinical features and management

Oral lichen planus (OLP) is a relatively common chronic inflammatory disorder affecting stratified squamous epithelia. Whereas in the majority of instances, cutaneous lesions of lichen planus (LP) are self-limiting and cause itching, oral lesions in OLP are chronic, rarely undergo spontaneous remission, are potentially premalignant and are often a source of morbidity. Current data suggest that OLP is a T cell-mediated autoimmune disease in which auto-cytotoxic CD8+ T cells trigger apoptosis of oral epithelial cells. The characteristic clinical aspects of OLP may be sufficient to make a correct diagnosis if there are classic skin lesions present. An oral biopsy with histopathologic study is recommended to confirm the clinical diagnosis and mainly to exclude dysplasia and malignancy. The most commonly employed and useful agents for the treatment of lichen planus (LP) are topical corticosteroids but other newer agents are available.

Methylene blue-mediated photodynamic therapy: A possible alternative treatment for oral lichen planus

BACKGROUND AND OBJECTIVES

In this study, methylene blue-mediated photodynamic therapy (MB-PDT) was used as a possible alternative method for the treatment of oral lichen planus (OLP).

STUDY DESIGN/MATERIALS AND METHODS

Thirteen patients with 26 OLP lesions were enrolled in this study. Patients were instructed to gargle a 5% methylene blue solution in water for 5 minutes. Ten minutes later, irradiation was performed by laser light (lambda = 632 nm, light exposure dose = 120 J/cm(2)). Lesions were evaluated pre and post-operatively and at follow-up sessions by changes in sign and symptom (pain) scores, and size of lesions.

RESULTS

Improvement in sign scores was achieved in 16 lesions. Four keratotic lesions disappeared completely. There was a statistically significant decrease in sign and symptom scores 1 week after treatment and at follow-up sessions up to 12 weeks. Average reduction in size of lesions was 44.3%.

CONCLUSION

MB-PDT seems to be an effective alternative treatment for control of OLP. In our opinion, this preliminary result warrant further studies in order to show the efficacy of MB-PDT in control of OLP for a longer period of time.

A clinical study of 674 patients with oral lichen planus in China

BACKGROUND

Oral lichen planus (OLP) is a chronic inflammatory disease with different clinical presentations that can be classified as reticular, atrophic or erosive. Although OLP is a relatively common disorder, the reports comprising large numbers of OLP patients with specific character are lacking in the literature. The purpose of this paper was to describe the clinical characteristics of OLP in 674 Chinese patients.

METHODS

A total of 674 charts of patients with histologically confirmed OLP were collected from Stomatological Hospital of Wuhan University between 1963 and 2003.

RESULTS

Of the 674 patients, 65.9% were women and 34.1% were men. The most common clinical presentation was the reticular type (51.3%), and symptomatic OLP was noted in 67.5% of the patients, mainly in those with the erosive form. The erosive presentations showed significantly longer duration, more sites affected and a much greater old patients predominance than reticular or atrophic ones. About 90.9% of the patients had multiple oral sites of involvement and isolated lower lip lichen planus were observed in 60 cases (8.9%) and isolated gingiva lichen in only one case (0.2%). Skin involvement of lichen planus was found in 11.4% of patients. No statistically significant differences could be identified between OLP and diabetes, cardiovascular disease, smoking or alcohol use. Precipitating factors that resulted in an exacerbation of the disease were frequently noted and included foods, stress, dental cusp and poor oral hygiene. The transformation of OLP into malignancy was observed in four patients at sites previously diagnosed by clinical examination as erosive or atrophic lichen planus.

CONCLUSIONS

Patients with OLP in China usually present with distinctive clinical morphology and characteristic distribution and few may display lesions with a confusing array of forms mimicking other diseases. A long time follow up is of utmost importance to detect its malignant transformation.

Higher expressions of p53 and proliferating cell nuclear antigen (PCNA) in atrophic oral lichen planus and patients with areca quid chewing

OBJECTIVE

The aim of the study was to examine the expressions of p53 and proliferating cell nuclear antigen (PCNA) in oral lichen planus (OLP) in relation to its clinical behavior and the patients' oral habits.

STUDY DESIGN

Immunohistochemical study was carried out to investigate the expressions of p53 and PCNA in 56 OLP specimens. The results were correlated with the clinical behavior of the disease and the patients' oral habits. The expression rates were further compared with those of normal oral mucosa (NOM), epithelial hyperkeratosis (EH), epithelial dysplasia (ED), and squamous cell carcinoma (SCC).

RESULTS

The staining rate of p53 (28.6%) and PCNA labeling index (LI) (27.6 +/- 8.8%) in OLP were similar to those in EH ( P = .868, .074, respectively), but higher than those of NOM and lower than those of ED and SCC (all P < .05). In OLP, no significant correlations were found between p53 or PCNA expression and the patients' age, gender, lesion duration, location, size, number of site, presence of pain, presence of local irritant, and the habits of alcohol drinking and cigarette smoking (all P > .05). In addition, the mean PCNA LI of p53+ cases was close to that of p53- cases (P = .38). However, the staining rate of p53 in OLP was higher in areca quid (AQ) chewers compared to abstainers (P = .001), and the mean PCNA LI in atrophic cases was higher than that in hypertrophic cases (P = .029). Interestingly, the staining rate of p53 and mean PCNA LI were significantly increased in AQ chewers with atrophic OLP (100%, 36.7% +/- 9.0%, respectively), which were similar to those in ED and SCC (all P > .05).

CONCLUSIONS

Although this study could not confirm the precancerous nature of OLP by the relatively low p53 and PCNA expression, the results do suggest that atrophic form OLP and patients with AQ chewing habit may have a higher disease activity in view of higher expression rates of p53 and PCNA in the lesions.

HPV DNA in clinically different variants of oral leukoplakia and lichen planus

OBJECTIVES

Our objectives were to determine the prevalence of human papillomavirus (HPV) infection in oral leukoplakia (OL) and oral lichen planus (OLP) in comparison with that in healthy oral mucosa, also conditionally to age, gender, smoking, and drinking habits of patients, so as to investigate any possible association of HPV infection with a specific clinical variant of OL or OLP.

STUDY DESIGN

We did research on HPV DNA in 68 cases of OL (homogeneous form [H] in 45 cases and nonhomogeneous form [non-H] in 23 cases), and in 71 cases of OLP (nonatrophic/erosive form [non-AE] in 27 cases, atrophic/erosive form [AE] in 44 cases). HPV DNA was investigated in exfoliated oral mucosa cells by nested PCR (nPCR: MY09-MY11/GP5-GP6) and the HPV genotype determined by direct DNA sequencing.

RESULTS

HPV DNA was found in 17.6% of OL, in 19.7% of OLP, and in 5.6% of controls, with a statistically significant higher risk of HPV infection in both lesion groups (for OL: P=.01; Odds Ratio [OR]=3.64; 95% CI: 1.21-10.80; for OLP: P=.005; OR=4.17; 95% CI: 1.41-12.18). Demographic variables analysis showed that the only significant association was between HPV status and current smoking in OL patients (OR'=3.40; 95% CI: 1.0-11.59). HPV DNA was found in 20% of H OL and 13% of non-H OL, without any association with the clinical variant (P=.73; OR=0.60; 95% CI: 0.14-2.48). HPV DNA was found in 18.5% of non-AE OLP and 20.4% of AE OLP, without any significant association with the clinical variant (P=.84; OR=1.13; 95% CI: 0.335-3.816). HPV-18 was the most frequently detected genotype (9/12 and 10/14 of HPV-positive OL and OLP, respectively), followed by HPV-16 (2/12 OL and 2/14 OLP), HPV-33 (1/12 OL), HPV-31 (1/14 OLP), and HPV-6 (1/14 OLP).

CONCLUSIONS

An increased risk of HPV infection was found in OL and OLP; however, no specific clinical variant of OL or OLP was noted to be associated with HPV infection. It is not possible to predict the likelihood of HPV infection from the clinical features of OL and OLP.

Smoking habits among patients diagnosed with oral lichen planus

INTRODUCTION

Oral lichen planus (OLP) is one of the most common dermatologic diseases that manifests in the oral cavity. The purpose of this study was to evaluate the association between smoking habits and the clinical subtypes of OLP.

METHODS

Oral findings and smoking data from 187 charts of OLP patients from an oral medicine clinic was reviewed and compared to data from 76 matched control patients.

RESULTS AND DISCUSSION

Ninety-three patients were diagnosed with reticular OLP, 55 with atrophic and 39 with erosive forms of the disease. Symptomatic OLP occurred in 63.6% of patients. Fewer cases of reticular OLP were symptomatic than erosive OLP (p < 0.001). Significantly fewer OLP patients smoked than the control group (16% versus 25%) (p = 0.04). More patients with reticular OLP smoked than those with atrophic and erosive OLP (p = 0.002). It is hypothesized that the heat and irritation of smoking may aggravate symptomatic OLP lesions, and the risk of malignant transformation associated with tobacco use may play a role in patients stopping tobacco use. Because there were fewer smokers in patients with OLP, and because OLP carries an increased malignant risk, transformation of OLP may be due to a different etiology and of a different pathogenesis than squamous cell carcinoma not arising from lichen planus. Close follow-up of patients with OLP is indicated.

Squamous cell carcinoma arising in an oral lichenoid lesion

BACKGROUND

Oral lichen planus, or OLP, is a chronic inflammatory mucocutaneous disease that frequently involves the oral mucosa. Lichenoid dysplasia, or LD, refers to lesions that could be mistaken clinically for OLP but have histologic features of dysplasia and a true malignant predisposition. Published case reports of OLP conversion to squamous cell carcinoma, or SCC, have created a great deal of controversy about the true nature of OLP, highlighting the need to verify its clinical diagnosis histologically.

CASE DESCRIPTION

The authors document the development of SCC in a 58-year-old woman with an oral lesion diagnosed clinically as OLP and described histologically as having lichenoid features with dysplastic changes. The time from the initial diagnosis of oral lichenoid lesions to the patient's return visit to the medical center with clinically evident cancer was three years and eight months. The SCC developed in the labial mucobuccal fold and left mandibular edentulous ridge, which had undergone multiple biopsy procedures.

CLINICAL IMPLICATIONS

This case does not provide answers to the ongoing controversy about the innate propensity of OLP to become malignant. However, in view of both the common occurrence of OLP and unresolved issues regarding its premalignant potential, this case report illustrates the need for histologic confirmation and close follow-up of patients with clinical lesions that have lichenoid features.

Risk of oral squamous cell carcinoma in 402 patients with oral lichen planus: a follow-up study in an Italian population

The most important complication of oral lichen planus (OLP) is the development of oral squamous cell carcinoma (OSCC) but this is a very controversial matter. The aim of the study was to estimate in a Northern Italian cohort of OLP patients the risk for OSCC. Four hundred and two patients with histologically confirmed OLP diagnosed from January 1988 to July 1999, were followed-up to the end of February 2001. The standardized incidence ratio (SIR) of OSCC was calculated for the entire cohort and specific for gender, type of OLP, therapy for OLP and hepatitis C virus (HCV) infection. The relative risk (RR) of OSCC according to HCV infection was also estimated in the cohort. During the follow-up period, two men (1.3%) and seven women (2.9%) developed an OSCC. The SIR was 44.9 (95% CI: 20.5-85.2), being higher among women, but statistically significant in both genders. The RR of OSCC for patients with HCV as compared with those without HCV infection was 3.16 (0.8-12.5). Patients with OLP had a significantly increased risk of OSCC, irrespective of the clinical type of OLP and therapy. HCV infection apparently increased the risk for OSCC although this result could reflect the role of confounders, such as liver cirrhosis.

Cancer and oral lichen planus in a Swedish population

Oral lichen planus (OLP) is generally regarded as a premalignant condition. The objective of the present study was to assess the number of oral malignant tumours in a retrospective analysis of 1028 patients (mean age=55 years; range=18-86; female, n=667; men, n=351) who between 1978 to end of 1993 were diagnosed with OLP at the Faculty of Odontology, Göteborg University, Sweden. Patients with malignant tumours were identified through the Swedish Cancer Registry at the National Board of Health and Welfare, which annually reports the incidence of malignant neoplasms in the Swedish population. The incidence of oral squamous cancer (OSCC), other malignant tumours and survival in the study group was compared to the Swedish population. The total time with OLP in the study group amounted to 7009 person years, with a mean follow up of 6.8 years (SD=4.9). The observed incidence of OSCC was higher than the expected incidence in the study group. The difference was statistically significant (P<0.001). No statistically significant difference was found for any other malignant tumours than OSCC. Also, no statistically significant difference could be identified in survival between study group and the population. The results from the present study gives further support to the concept of a small but increased risk for development of squamous cell carcinoma in patients with OLP.

Transformación maligna del liquen plano oral en tres nuevos casos

The possible malignant potential of oral lichen planus (OLP) is still controversial. We present three new oral lichen planus (OLP) patients who developed oral squamous-cell carcinoma (OSCC). In all cases, were analyzed variables like sex, age, clinical type, localization, extension, follow-up study and treatment, moreover were considered the patient's habits, localization, stage and treatment of cancer. The average age was 59 years and both of them were non smoker or with no alcohol habits. The follow-up period was greater than two years and the malignant lesion developed after mean of nine years, after the diagnosis of OLP had been established. Oral squamous-cell carcinoma (OSCC) arose on lesions previously diagnosed clinically and histologically as atrophic and erosive oral lichen planus in two of our patients and on a plaque lesion LP in a patient. All of them had been using topical corticoids before the cancer was diagnosed. The appearance of new cases of OLP malignization framed inside the established approaches, suggests the realization of new researches in order to determine the factors involved in this process.

Expression of hMSH2 protein of the human DNA mismatch repair system in oral lichen planus

Lichen planus is a mucocutaneous disease of inflammatory nature and unknown etiology. It is characterized by a cell-mediated immunological response to induced antigenic change in skin and/or mucosa. The possible malignant transformation of lichen planus remains a subject of controversial discussions in the literature. hMSH2 is one of the human DNA mismatch repair (hMMR) genes and it plays an important role in reducing mutation and maintaining genomic stability. hMSH2 alterations have been reported in oral squamous cell carcinoma and there are evidences suggesting the association between oral lichen planus and squamous cell carcinoma. In this study, we aim to investigate the immunolocalization of hMSH2 protein in oral lichen planus compared to oral normal mucosa epithelium. We examined the expression of hMSH2 protein by immunohistochemistry in twenty-six cases of oral lichen planus. Clinically, 12 of them were categorized into reticular subtype and 14 were atrophic/erosive. Ten cases of normal mucosa were added to the control group. Results showed that the percentage of positive cells to hMSH2 was smaller in reticular (46.54%; p=0,006) and atrophic/erosive (48.79%; p=0,028) subtypes of oral lichen planus compared to normal mucosa (61.29%). The reduced expression of hMSH2 protein in oral lichen planus suggests that this lesion is more susceptible to mutation and therefore facilitate the development of oral squamous cell carcinoma.