Association of oral lichen planus and psoriasis: a case-control study.

OBJECTIVE: The aim of the present study was to investigate whether psoriasis disease constitutes a risk factor for OLP, by assessing the prevalance of psoriasis in a test group with OLP and the control group without. METHOD AND MATERIALS: A cohort of consecutive patients diagnosed clinically and histologically with OLP between 2014 and 2022 was analyzed. The results were contrasted with those obtained in control series matched for age and sex. The correlations between OLP and sex, age, tobacco, alcohol consumption, and psoriasis were assessed using Pearson chi-square test. Multivariate regression analysis was performed to evaluate the association between psoriasis and OLP. For the assessment of the quality of the statistical models, the Akaike information criterion was used. RESULTS: The study involved 1,016 patients; 738 women (72.6%) and 278 men (27.4%). The average age was 59.38 ± 12.55 years. Of 508 patients with OLP, 16 (3.15%) had comorbid psoriasis, and this was 5 (0.98%) in the control group. Age, sex, smoking, and alcohol habits were not predictive variables in the relationship between psoriasis and OLP in these patients. There were statistically significant differences in relation to the number of locations, with greater extension in patients with OLP and psoriasis (P = .002). According to the multivariate analysis, the odds ratio of OLP for psoriasis was 3.13 (95% CI 1.20-9.68). CONCLUSIONS: This is the first study showing the potential association between psoriasis and OLP, and the results should be considered to improve knowledge of comorbidity of OLP. Based on the results, it is recommended that clinicians collect data regarding history of psoriasis in patients with OLP, and consider possible multiple intraoral locations.

Oral lichen planus in children: An Italian case series.

Oral lichen planus usually occurs in adults; there are no clear data regarding the incidence and the clinical features of oral lichen planus in children. This paper reports clinical findings, treatments, and outcomes of 13 Italian patients with oral lichen planus in childhood diagnosed between 2001 and 2021. The most common finding was keratotic lesions with reticular or papular/plaque-like patterns, confined to the tongue in seven patients. Although oral lichen planus in childhood is rare and the malignant transformation index is unknown, specialists must be aware of its characteristics and oral mucosal lesions must be correctly diagnosed and managed.

Oral lichen planus: case series and experience in a tertiary dermatology service in Brazil.

BACKGROUND: Lichen planus is an inflammatory disease that can affect both the skin and mucous membranes, including the oral mucosa. There is very little original Brazilian dermatology literature about oral lichen planus. OBJECTIVE: To describe the clinical, pathological, and treatment data of 201 patients diagnosed with oral lichen planus followed at the Stomatology Outpatient Clinic of Hospital das Clínicas, Universidade de São Paulo, from 2003 to 2021. METHOD: The patients demographic profile, the morpho-topographic features of the lesions, the treatment employed, and the possible presence of squamous cell carcinoma were analyzed. RESULTS: The disease was more common in women over 50 years of age, tending to be chronic, with a large number of cases showing cicatricial sequelae in the mucosa. Topical treatment with potent corticosteroids was shown to be effective in the vast majority of cases. Squamous cell carcinoma in oral lichen planus cicatricial sequelae was observed in eight cases. STUDY LIMITATIONS: Retrospective study of medical records, with gaps regarding the filling out of data; unequal observation time among the studied cases. CONCLUSIONS: This is the largest Brazilian dermatology series on oral lichen planus. The response to topical corticoid therapy was excellent in the vast majority of cases. The high prevalence of atrophic lesions, demonstrating the chronicity and tissue destruction potential of this disease, may explain the large number of cases of squamous cell carcinoma.

Gingival lichen planus: A clinical and pathological study.

BACKGROUND: Oral lichen planus (OLP) is a common immune-mediated chronic inflammatory disease affecting the oral mucosa. It is most likely to occur in adults, particularly in women. The most commonly affected areas are the buccal mucosa, tongue and gingiva, either alone or in combination. The aim of this study was to analyse the clinicopathological characteristics of gingival lichen planus in a series of patients diagnosed between 2000 and 2019. MATERIALS AND METHOD: Files of 190 patients with histopathologically confirmed gingival lichen planus were retrieved from the archives of the Laboratory of Oral and Maxillofacial Pathology of the Geneva University Hospitals. We analysed the demographic characteristics of the patients, the location, clinical presentation and histopathological characteristics of the lesions, and the presence of symptoms. RESULTS: The majority of the patients were women (74.2%). The age ranged between 12 and 88 years of age, with a mean of 58.6 years. 79 cases (41.6%) of gingival lichen planus were confined to the gingiva. In the remaining cases, the gingival lesions were associated with other localisations, mostly the buccal mucosa and the tongue, as well as other intraoral and extra-oral sites. 38.7% of the patients presented mixed form of OLP, 27.8% keratotic form and 22.4% erythematous/erosive form. The mixed and the erythematous/erosive forms were the most symptomatic lesions. The majority of gingival lichen planus were active atrophic. A total of seven malignant transformation were found (3.7% of the cases). CONCLUSION: Gingival lichen planus is a chronic disease that can have many different clinical and histological presentations. Long-term regular follow-up of gingival lichen planus is recommended to detect signs of malignant transformation.

Autoimmune disorders in oral lichen planus: A systematic review and meta-analysis.

OBJECTIVES: The association of OLP with other autoimmune processes points to the possibility that OLP-affected patients are actually developing an autoimmune status that predisposes them to autoaggression against different targets. This systematic review and meta-analysis aim to evaluate the current evidence on the prevalence of autoimmune disorders in patients with OLP and their magnitude of association. METHODS: We searched PubMed, Embase, Web of Science, Scopus databases for the studies published before May 2021, with no limitation in regards to their publication date or language. We evaluated the quality of studies, carried out meta-analyses and performed heterogeneity, subgroups, meta-regression, and small-study effects analyses. RESULTS: Inclusion criteria were met by 153 studies (23,327 patients). Our results indicate the existence of high prevalence and a frequent association between OLP and some autoimmune disorders, especially in regards to thyroid disease (PP = 7.96%, 95% CI = 6.32-9.75; OR = 1.99, 95% CI = 1.60-2.49, p < 0.001) and diabetes mellitus (PP = 9.41%,95% CI = 8.16-10.74; OR = 1.64, 95% CI = 1.34-2.00, p < 0.001). CONCLUSIONS: Our study demonstrates the existence of a comorbidity between autoimmune thyroid diseases as well as between diabetes mellitus and OLP respectively. Quality of evidence should be upgraded on other autoimmune diseases (fibromyalgia, gastrointestinal disorders, rheumatic diseases, Sjogren's syndrome, lupus erythematosus, and dermatological diseases) for which the current data do not allow us to know whether they are really associated with OLP.

Patient Characteristics Associated with the Development of Oral Lichen Planus in Two Provinces in Canada.

OBJECTIVES: To understand the risk factors that may be associated with the development of oral lichen planus (OLP) and its progression. STUDY DESIGN: We conducted retrospective chart reviews of adult patients with OLP who presented to oral medicine and oral pathology clinics in 2 provinces between September 2016 and January 2020. Data regarding age, sex, disease duration, sites of involvement, comorbidities, medications, allergies, smoking, alcohol use, treatment and follow up were collected. Descriptive statistics were assessed. RESULTS: Among the 94 patients with OLP, mean age was 62 years and most were female (73%). Mean disease duration was 3.1 years. Hypertension, thyroid disorders and diabetes were present in 32%, 28% and 17% of patients, respectively. A significant proportion of patients reported a major surgical procedure (47%) as a preceding event and an additional 7% reported a preceding stressful life event. Three OLP patients (3%) developed squamous cell carcinoma or dysplasia. The mean disease duration for these patients was 4.06 years and the frequency of biopsy in our study was approximately 14%. CONCLUSIONS: Female sex, endocrine and immunological comorbidities, such as thyroid disease and diabetes, and psychological stress may play a role in the development of OLP in the Canadian population. A small percentage of patients may develop malignant transformation and, thus, require long-term monitoring.

EPIDEMIOLOGICAL SITUATION OF PRE-CANCER DISEASES OF THE ORAL MUCOUS IN UKRAINE.

OBJECTIVE: The aim: To conduct a prospective clinical study to assess the prevalence, structure, risk factors and features of clinical manifestations of precancerous diseases of oral mucosa and red lip in Kyiv residents and to analyze opportunities to improve the quality of their primary diagnosis. PATIENTS AND METHODS: Materials and methods: The examination of 423 patients with precancerous diseases of oral mucosa and red lip included clarification of the main complaints and anamnesis of the disease, objective assessment of the state of oral mucosa and red border of the lips according to visual, stomatoscopic, luminescent analysis, cyto-, histological studies. RESULTS: Results: Attention is drawn to the prevalence among precancerous diseases of patients with leukoplakia - 41.37% and lichen planus - 44.21%. The levels of detection of precancerous diseases of the oral mucosa due to the current and preliminary history for individual nosological forms are almost identical, which indicates the reliability of the above indicators. CONCLUSION: Conclusions: Promotion between the people about timely dental treatment for precancerous diseases of the oral mocosa and the use of radical technologies in their treatment will not only increase the effectiveness of treatment, but significantly limit the malignancy of these diseases.

THE PROPORTION OF ORAL LICHEN PLANUS CASES WITH MALIGNANT TRANSFORMATION MAY BE HIGHER, THAN REPORTED TO DATE.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: González-Moles MÁ, Ramos-García P, Warnakulasuriya S. An appraisal of highest quality studies reporting malignant transformation of oral lichen planus based on a systematic review. Oral Dis. 2021 Nov;27(8):1908-1918. doi: 10.1111/odi.13741. Epub 2020 Dec 24. PMID: 33274561. SOURCE OF FUNDING: The Royal College of Physicians and Surgeons (RCPSG) provided logistic support for holding the expert symposium. Henry Schein Cares provided an educational grant for travel expenses for some of the invited experts. TYPE OF STUDY/DESIGN: Systematic review with meta-analysis.

Are oral lichen planus patients at high risk of hepatitis C? A case-control study.

OBJECTIVE: To assess the correlation between oral lichen planus (OLP) and viral hepatitis C (HCV). METHODS: This retrospective case-control study included a sample of OLP patients in a 3-year interval. The predictor variable was the presence of OLP (yes/no). The outcome variable was the diagnosis of HCV. Other study variables were grouped into demographic, anatomic, and clinical. Descriptive, bi- and multivariate statistics were computed with a significant level at P ≤ 0.05. RESULTS: The sample was composed of 237 OLP patients (38.8% females) with a mean age of 59.9 ± 17.8 years (range, 17-96), and 948 age- and gender-matched control individuals. The significant higher frequency of HCV was identified in OLP patients (frequency: 19.8% vs. 2.1%; adjusted matched odds ratio [mORadj], 9.5; 95% confidence interval [95% CI], 5.98 to 15.91; P < 0.0001; Pearson's Phi coefficient [rphi], 0.307). In the adjusted model, OLP with HCV was associated with 1) oro-cutaneous manifestations (mORadj, 17.58; 95% CI, 1.92 to 161.26; P = 0.0059; Bayesian posterior probability of positive test [Wp], 96%), 2) any intraoral forms other than reticular/plaque-liked forms (mORadj, 0.09; 95% CI, 0.04 to 0.18; P < 0.0001; Wp, 52%), and 3) poor response to topical corticosteroids (mORadj, 0.05; 95% CI, 0.02 to 0.16; P < 0.0001; Wp, 88%). CONCLUSIONS: OLP, especially oro-cutaneous disease or steroid-refractory OLP, are associated with an increased frequency of HCV. Not only HCV screening in OLP patients, but oral examination in HCV patients, are both recommended as primary preventive measures.

Prevalence of Merkel Cell Polyomavirus (MCPyV) in the Oral Cavity Biopsies in Northern Iran.

OBJECTIVE: Infection with human tumor viruses is one of the hypothesized causes of cancer. The current investigation aimed to explore the presence and quantitative analysis of a new human tumor virus, Merkel cell polyomavirus (MCPyV) in tissue samples of 114 patients with oral cavity lesions including oral squamous cell carcinoma (OSCC), oral lichen planus (OLP), Dysplasia and oral irritation fibroma (OIF) in Northern Iran. METHODS: From 114 formalin fixed paraffin embedded samples; 35 with SCC, 29 with OLP, 14 with dysplasia and 36 with OIF were cut, deparaffinized and DNA was extracted. Quantitative detection of MCPyV large T antigen was performed by absolute quantitative Real-Time PCR. RESULT: MCPyV DNA was detected in 30.6% (n: 11/36) of IF, 24.1% (n; 7/29) of OLP, 21.4% (n:3/14) of dysplasia and 20% (n;7/35) of OSCC samples. The mean MCPyV DNA copy number was 2.32×10-2 ± 3.97 ×10-2, 2.02×10-2 (SD=3.13×10-2), 2.69×10-4 (SD=2.51×10-4), and 2.56×10-4 (SD=6.73×10-4) per cell in OSCC, dysplasia and both of OLP and OIF samples, respectively (P=0.76). CONCLUSION: This study provides the first data from Iran regarding the presence of MCPyV genome in oral cavity lesions and oral cancer. These results also emphasize that MCPyV has an active role in the occurrence of oral lesions and progression to cancer. Further studies should be carried out to clarify the role of MCPyV in oral cavity lesions.

The Characteristics of Patients with Oral Lichen Planus and Malignant Transformation-A Retrospective Study of 271 Patients.

INTRODUCTION: Oral lichen planus (OLP) is a chronic inflammatory disease with an unknown etiology rating among oral potentially malignant disorder. The aim of the study was to determine the epidemiological and clinical characteristics of the patients with OLP and rate of malignant transformation. PATIENTS AND METHODS: Data were obtained from the medical records of 271 patients referred to the Oral Medicine Unit at the University Hospital in Hradec Králové diagnosed with oral lichen planus in the period of 2003-2020. The records were retrospectively analyzed. The following clinical data were retrieved from the medical charts: gender, age, systemic diseases, alcohol and tobacco consumption, localization/clinical appearance of lesions, distribution of the lesions, presence of the symptoms, treatment provided and malignant transformation. RESULTS: A total of 271 charts of patients with confirmed diagnosis of OLP were retrospectively analyzed, of whom, 66.4% (180/271) were women and 33.6% (91/271) were men. The mean age of the patients was 56.0 (18.2-85.0) years. The median follow-up of all patients was 15.2 months. Overall, 2 patients (2/271, 0.74%) meeting the above-mentioned criteria for malignant transformation were identified during the follow-up period. Both patients suffered from erosive type OLP and developed squamous cell carcinoma of the tongue. CONCLUSIONS: This retrospective study is in concordance with other studies showing the similar profile and clinical features of the patients with OLP. Malignant transformation rate was 0.74%.

High Prevalence of Human Papillomavirus Type 18 in Oral Potentially Malignant Disorders in Thailand.

OBJECTIVES: The main objectives of this study were to investigate the detection rate of high-risk human papillomavirus types 16 and 18 (high-risk HPV16/18) in oral potentially malignant disorders (OPMDs) including oral leukoplakia (OL) and oral lichen planus (OLP) in a Thai population and their associations with demographic, risk habits, and clinicopathologic features. METHODS: Paraffin-embedded formalin-fixed specimens from 101 OL and 59 OLP patients with patients' demographic, risk habits, and clinicopathologic data were collected. Conventional qualitative polymerase chain reaction was used to detect high-risk HPV16/18 DNA. Associations between high-risk HPV type 16/18 and demographic, clinicopathologic, risk factors (tobacco and alcohol uses) of OPMDs were analysed by Chi-square or Fisher's exact test. The results with p value less than 0.05 were considered statistically significant. RESULTS: HPV16/18 DNA was found in both OL and OLP groups with the detection rate of 19.8% and 18.6%, respectively. Approximately 90% of high-risk HPV were HPV18 subtype. Additionally, in OL group, high-risk HPV was found more frequently in patients with moderate/severe dysplasia than that in mild dysplasia. Interestingly, in OLP group, high-risk HPV was only detected in atrophic/ulcerative subtypes. None of risk factors was associated with high-risk HPV. CONCLUSIONS: Approximately 19% of OPMDs were HPV16/18-positive. HPV18 DNA was predominantly detected in both OL and OLP patients (90%). Additionally, the detection rate of high-risk HPV was higher in more severe dysplastic cases of OL and more clinically severe cases of OLP.

Prevalence of HPV in patients affected by oral Lichen planus: A prospective study using two different chair-side sampling methods.

BACKGROUND: Human Papillomavirus (HPV) role in oral potentially malignant lesions remains unclear. Aims of this study were to evaluate the prevalence of HPV infection in a cohort of patients affected by oral lichen planus, to analyze the genotypes involved, and to compare the performance of two specimen collection methods: brushing and biopsy. METHODS: Consecutive patients with oral lichen planus were enrolled. Each patient's clinical and anamnestic data were recorded before he/she underwent brushing and biopsy procedures. The collected samples were analyzed using RT-PCR. Prevalence of HPV infection was evaluated considering cytobrush and biopsy outcomes alone and combined. Correlation between HPV presence and sex, age, smoke, alcohol, kind of lichen planus, Hepatitis C virus, and involved mucosae was analyzed using chi-square test (significance at P < .05). Cohen's k coefficient was employed to compare brushing and biopsy. RESULTS: Fifty-two patients affected by oral lichen planus were enrolled. Total HPV prevalence was 17%, when considering only the biopsy and the cytobrush the prevalence was 15% and 6%, respectively. None of the considered variables showed significant correlation with HPV (P > .05). The concordance between the two methods was "fair" (k = .305). CONCLUSIONS: The biopsy appears more reliable than cytobrush to detect HPV in course of oral lichen planus. No statistical correlation emerged with the analyzed variables. The most frequently detected genotypes were HPV 6 and 11, while only two cases presented with HPV 16 and 53, known as human oncogenic.

Worldwide prevalence of oral lichen planus: A systematic review and meta-analysis.

The objective was to assess the global oral lichen planus prevalence. We searched PubMed, EMBASE, Web of Science, and Scopus for studies published before September 2019. We evaluated the quality of studies and carried out several meta-analyses. The global pooled prevalence was 1.01%, with a marked geographical difference (p < .001). The highest prevalence was reported from Europe (1.43%) and the lowest in India (0.49%), where tobacco-associated keratosis appears to mask oral lichen planus resulting in attenuation of its prevalence. From the age of 40 years, the prevalence increases significantly and progressively (OR = 3.43, 95% CI = 2.48-4.73, p < .001). Studies that define diagnostic criteria report a higher prevalence (1.31% vs. 0.70%, p = .03), although the application of the WHO criteria (year 1978-2007) does not increase the ability to diagnose the disease compared with other criteria (p = .11). The studies performed by oral medicine/oral pathology specialists report significantly higher prevalence (1.80%) than dentists (0.61%) and dermatologists (0.33%; p < .001). In conclusion, we propose that reliable diagnostic criteria should be defined, which should include a set of essential criteria including the presence of white reticular lesions in any location of the oral mucosa. The impact of histopathological confirmation with defined diagnostic criteria must be researched in the future, although its main use should be to determine the presence or absence of epithelial dysplasia. The necessity to improve the knowledge of oral lichen planus among dentists and dermatologists through continuing education is apparent in the results of this meta-analysis.

Association between oral lichen planus and systemic conditions and medications: Case-control study.

OBJECTIVE: The aim of this study is to investigate the association between oral lichen planus (OLP) and a variety of systemic conditions, medication, and supplement usage. MATERIALS AND METHOD: A total of 156 patients diagnosed with OLP and 156 controls at Columbia University Irving Medical Center from 2000 to 2013 were selected as part of the matched (1:1) case-control study. Demographics, systemic conditions, prescription medications and supplements were extracted from the patients' medical records. A univariable conditional logistic regression (CLR) analysis was performed to calculate unadjusted odds ratio, to identify significant variables associated with OLP (p < .10). Significant variables were further tested using multivariable CLR analysis with both forward and backward selection to calculate adjusted odds ratio (aOR) and further distinguish variables associated with OLP (p < .05). RESULTS: This analysis identified six significant variables: thyroid disorder (aOR:5.1,95%CI:2.3-11.2), any form of cancer (aOR:3.4,95%CI:1.4-8.4), type 2 diabetes (aOR:2.8,95%CI:1.2-6.3), hyperlipidemia (aOR:2.3,95%CI:1.3-4.1), oral sedative usage (aOR:6.3,95%CI:1.8-22.5), and vitamin D supplementation (aOR:2.7,95%Cl:1.3-6.0). CONCLUSION: Thyroid disorders, cancer, type 2 diabetes, hyperlipidemia, sedatives, and vitamin D supplementation were found to be associated with OLP. Additional investigation is required to explore these associations, which could shed light on the potential mechanism of OLP and reinforce the idea that oral lesions could be predicative of previously undetected systemic conditions.

Oral lichen planus has a very low malignant transformation rate: A systematic review and meta-analysis using strict diagnostic and inclusion criteria.

BACKGROUND: The malignant transformation (MT) potential of oral lichen planus (OLP) has sparked heated debates for almost a century, despite the fact that global figures of OLP prevalence and oral cancer incidence do not support an association mathematically. In this study, we performed a systematic review and meta-analysis, using strict inclusion criteria, to more precisely assess the malignant potential rate of OLP and the influence of associated risk factors. METHODS: All reports that documented MT of OLP and published in the English language until January 2020 were included if they met the following strict criteria: (a) the presence of a properly verified OLP diagnosis, (b) a clear description of the cancerous lesion developing at the same site as the verified OLP lesion; and (c) a follow-up period of a minimum of 6 months prior to carcinoma development. RESULTS: Thirty-three studies were included in this analysis with a total of 12 838 OLP patients. Of these, 151 cases were initially considered to have progressed to carcinoma (1.2%). However, after applying strict criteria, only 56 cases were considered to have undergone MT from OLP (0.44%). The risk of MT was significantly higher among OLP patients who smoked (OR = 4.62), consumed alcohol (OR = 3.22), were seropositive for HCV (OR = 3.77) and/or displayed a red OLP subtype (OR = 0.37). CONCLUSIONS: Our results suggest that the reported OLP malignant transformation rates are exaggerated, and these do not reflect the actual clinical course of the disease according to strict clinical and histopathological criteria.

The relationship between lichen planus and metabolic syndrome.

OBJECTIVE: Lichen planus (LP) is an idiopathic, chronic inflammatory disease. Chronic inflammatory diseases can cause metabolic complications. In the literature, data related to the relationship between lichen planus and metabolic syndrome (MS) are limited. We aimed to evaluate the relationship between MS and lichen planus with disease activity. METHODS: The patients diagnosed with lichen planus at the dermatology outpatient clinic between January 2018 and January 2020 were retrospectively analyzed. 98 lichen planus cases, age- and sex-matched 99 controls, 197 cases in total were included in the study. RESULTS: Of the 98 lichen planus cases included in the study, 60 (61%) were women. The mean age of the patients was 49.3 ± 14.4, and the average disease duration was 33.5 ± 31.4 months. 55 (55%) of the patients in the control group were female, and the mean age of the control group was 50 ± 13.2. The body mass index of LP cases was 29.5 ± 5.8, in the control group was 25.8 ± 3.7. Metabolic syndrome was found in 47 (48%) of 98 cases with lichen planus and 32.3% in the control group. MS in the lichen planus group was significantly higher than the control group (P = .025). Metabolic syndrome was detected in the oral lichen planus at the rate of 60% (12 cases). Although the incidence of MS was more common in the oral lichen planus, it was not statistically significant (P = .29). While no significant relationship was found between oral disease severity and metabolic syndrome (P = .19), a significant correlation was found between cutaneous disease severity and metabolic syndrome (P = .023). DISCUSSION: The risk of mucosal malignancy that can occur when following LP cases has been known for a long time. According to our results, caution should be taken in terms of metabolic complications in the follow-up of LP cases, especially oral LP cases.

Malignant transformation of oral lichen planus. A retrospective analysis from 2003-2014: our experience.

AIM: The aim of the study is to describe both the clinical characteristics and the prevalence of Oral lichen planus (OLP) in a group of patients from a region of Southern Italy. MATERIAL AND METHODS: Among the patients who referred to outpatient visit, 96 (35 men and 61 women) received diagnosis of OLP according to Van der Meij and Van der Wall criteria. RESULTS: Nine of ninty-six cases observed developed squamous cell carcinoma (9,37%). The risk of malignant transformation was significantly higher among OLP patients who smoked (OR=2,5 P< 0,05), consumed alcohol (OR=3 P< 0,05), came from the province with a ratio province: city of 4,5:1 and had the reticular form (44.4%). DISCUSSION: Oral lichen planus (OLP) is an oral subtype of lichen planus with a prevalence in the world population estimated between 0.22% and 5% and an incidence approximately of 2.2%. The analysis of our results revealed an important information about the prevalence of malignant transformation, which is 9.37%. CONCLUSION: The transformation of the oral lichen planus may not be as rare as one would expect. The malignant transformation rates of OLP are underestimated due essentially to restrictive diagnostic criteria, inadequate follow-up periods, and/or low quality of studies. Close surveillance is mandatory to monitoring the growth and evolution of lesions in order to reduce the morbidity of OSCC. KEY WORDS: Malignant transformation, Oral lichen Planus, Squamous cell carcinoma of the oral cavity.

Malignant transformation in oral lichen planus and lichenoid lesions: a 14-year longitudinal retrospective cohort study of 829 patients in New Zealand.

OBJECTIVE: The aim of this study was to identify the rate of malignant transformation in a longitudinal cohort of patients with oral lichen planus and oral lichenoid lesion (OLP/OLL) and to assess the associations between clinicopathologic aspects and malignant transformation. STUDY DESIGN: Data were taken from the records of 829 patients histologically diagnosed with OLP/OLL in the years 2005 to 2018. RESULTS: Of the study patients, 548 (66.1%) were females and 281 (33.9%) were males. The average age at diagnosis was 57.3 years. The hyperplastic type was the most frequent (58.5%). Most patients had multiple sites of involvement, with the buccal mucosa being the most frequent site of biopsy. Oral epithelial dysplasia developed in 5 (0.6%) patients with a previous histologic diagnosis of OLP/OLL and developed oral squamous cell carcinoma (OSCC) in 23 patients (2.8%) during the follow-up period. The atrophic/ulcerative forms are 25.8 times more likely to progress to OSCC compared with the hyperplastic types (hazard ratio [HR] 25.8; P < .05). The HR increases by 5% with every year of age (HR 1.05; 95% confidence interval; P < .05). CONCLUSIONS: In our study, oral epithelial dysplasia developed in less than 1% of patients with OLP/OLL, and OSCC in 2.8%during the follow-up period. The atrophic/ulcerative forms are 25.8 times more likely to progress to OSCC compared with the hyperplastic types. The HR increases by 5% with every year of age.