Clinical features of oral lichen planus and oral lichenoid lesions: an oral pathologist's perspective

Abstract The clinicopathological features that precisely characterize oral lichen planus (OLP) and oral lichenoid lesions (OLL) still represent a challenge. The aim of the present study was to analyze, from an oral pathologist perspective, the clinical features from OLP and OLL. Specimens fullfilling the histological criteria for OLP and OLL, and also compatible with OLP (OLP-C), were selected and clinical information was retrieved from the laboratory forms. The final sample was composed by 221 cases, including 119 OLP (53.8%), 65 OLP-C (29.4%) and 37 OLL (16.7%). Females were more affected in the three groups, but the number of males was higher in OLL. Mean age was lower in OLP (52.3 years) in comparison with OLL (57.9 years) (p=0.020). Buccal mucosa and tongue involvement was more frequent in OLP; gingival involvement was uncommon in OLL. The reticular pattern was more frequently found in OLP, while the association of reticular and atrophic/erosive/ulcerated patterns was more common in OLP-C and OLL (p=0.025). In conclusion, gender and mean age of the patients, and anatomical location and clinical manifestation of OLL are different from OLP, and could help to better characterize this group of conditions. Specimens diagnosed as OLP-C showed clinical parameters close to OLP.

Resumo Os achados clinico-patológicos que caracterizam de forma precisa o líquen plano oral (LPO) e as lesões liquenoides orais (LLO) ainda representam um desafio. O objetivo do presente estudo foi analisar, pela perspectiva do patologista oral, os achados clínicos do LPO e das LLO. Espécimes preenchendo os critérios histológicos para o diagnóstico de LPO e LLO, e também aqueles compatíveis com LPO (LPO-C), foram selecionados e as informações clínicas foram obtidas a partir das requisições laboratoriais. A amostra final foi composta de 221 casos, incluindo 119 LPO (53.8%), 65 LPO-C (29.4%) e 37 LLO (16.7%). As mulheres foram mais acometidas nos três grupos, mas o número de homens acometidos foi maior nas LLO. A média de idade foi menor no LPO (52.3 anos) em comparação com as LLO (57.9 anos) (p=0.020). O envolvimento da mucosa jugal e da língua foi mais frequente no LPO; o envolvimento gingival foi incomum nas LLO. O padrão reticular foi mais frequentemente encontrado no LPO, enquanto a associação dos padrões reticular e atrófico/erosivo/ulcerado foi mais comum no LPO-C e nas LLO (p=0.025). Em conclusão, o gênero e a média de idade dos pacientes, assim como a localização anatômica e a manifestação clínica das LLO são diferentes do LPO, e podem ajudar a melhor caracterizar este grupo de condições. Espécimes diagnosticados como LPO-C mostraram parâmetros clínicos mais próximos ao LPO.

Análise clínico-patológica e qualitativa da expressão de mediadores inflamatórios teciduais no líquen plano oral / Clinicopathological and qualitative analysis of the expression of tissue inflammatory mediators in oral lichen planus

O líquen plano oral (LPO) é uma condição imuno-inflamatória mucocutânea crônica que ainda possui etiologia e patogênese desconhecidas. Estudos mostrando a participação de citocinas no LPO, em especial, interleucinas (IL)-6, IL-17 e IL-18, são escassos, assim como a correlação das características clínicas e histológicas das lesões de LPO com a presença destes mediadores inflamatórios. Todas as lesões de LPO e de lesões liquenoides orais (LLO) foram revisadas a partir do arquivo do laboratório de Patologia Bucal da Faculdade de Odontologia da Universidade do Estado do Rio de Janeiro e as características clínico-patológicas dos casos foram analisadas. Foram selecionados 40 casos de LPO para realização adicional de reações imuno-histoquímicas para IL-6, IL-17 e IL-18. A amostra total foi composta por 221 casos e mostrou que o LPO apresentou predileção por mulheres adultas, mais frequentemente acometidas pelo padrão reticular e com lesões localizadas predominantemente na mucosa jugal. Os 40 casos selecionados para a avaliação imuno-histoquímica incluíram pacientes com média de idade de 53 anos, sem predileção por gênero, e com lesões localizadas preferencialmente na mucosa jugal (85%), na gengiva/mucosa alveolar (47%) e na língua (42%). Quanto ao padrão clínico, 14 pacientes (35%) mostravam lesões exclusivamente reticulares e 26 (65%) mostravam lesões reticulares associadas a lesões atrófico-erosivas. Sintomas foram relatados por 53% dos pacientes e incluíram principalmente ardência e desconforto local. A análise histológica mostrou que o epitélio das lesões mostrava espessura normal, atrófica ou hiperplásica em, respectivamente, 17 (43%), 9 (22%) e 14 (35%) casos. A presença de hiperqueratose foi observada em 21 casos (53%) e exocitose de linfócitos T CD4+ e T CD8+ estava presente em, respectivamente, 17 (42%) e 30 (75%) casos. A análise imuno-histoquímica revelou que a IL-6 foi, de forma geral, a mais expressa, tanto no epitélio, quanto no conjuntivo. A expressão de IL-17 se mostrou intensa no tecido conjuntivo, em 40% dos casos. A IL-18 mostrou intensidade mais frequente leve/moderada tanto no epitélio (40%), quanto no tecido conjuntivo (45%). A presença de exocitose mostrou relação com a maior expressão das ILs e a expressão de IL-17 foi maior no epitélio mostrando hiperqueratose. Os resultados do presente estudo mostraram que as características clínicas das lesões de LPO e de LLO são distintas e podem ser utilizadas para diferenciação entre as duas entidades. Os achados histológicos e imunohistoquímicos sugerem que as ILs estudadas mostram-se mais presentes quando há exocitose linfócitos T CD4+ e T CD8+ e que sua expressão pode ter relação com as alterações epiteliais encontradas no LPO, participando da patogênese e da modulação da expressão da doença.

Oral lichen planus (OLP) is a chronic immunoinflammatory mucocutaneous condition of unknown etiology and pathogenesis. Studies focusing on the presence of cytokines in OLP, especially interleukin (IL)-6, IL-17 and IL-18, are scarce, as well as the correlation of clinical and histological characteristics with the presence of inflammatory mediators. All lesions diagnosed as OLP and oral lichenoid lesions (OLL) were reviewed from the files of the Oral Pathology laboratory, Dental School, Rio de Janeiro State University, and their clinicopathological characteristics were analyzed. Forty cases diagnosed as OLP were selected for additional immunohistochemical reactions directed against IL-6, IL-17 e IL-18. The total sample was composed by 221 cases and showed that OLP presented a predilection for adult females, mostly affected by lesions with the reticular pattern and located in the buccal mucosa. The 40 cases selected for the immunohistochemical reactions included patients with a mean age of 53 years, with no gender predilection, and with lesions located mostly in the buccal mucosa (85%), gingiva/alveolar mucosa (47%) and tongue (42%). The clinical pattern showed reticular lesions in 14 patients (35%) and reticular and atrophic/erosive lesions in 26 patients (65%). Symptoms were reported by 53% of the patients and included mostly burning sensation and local discomfort. Histological analysis showed that the epithelial thickness was normal, atrophic, or hyperplastic in, respectively, 17 (43%), 9 (22%) and 14 (35%) cases. The presence of hyperkeratosis was observed in 21 cases (53%), and exocytosis of T CD4+ and T CD8+ lymphocytes was present in, respectively, 17 (42%) and 30 (75%) cases. Immunohistochemical analysis showed that, in general, IL-6 was the most expressed IL both in epithelium and connective tissue. IL-17 expression was considered intense in the connective tissue from 40% of the cases. IL-18 expression was considered mostly mild/moderate both in epithelium (40% of the cases) and connective tissue (45% of the cases). The presence of exocytosis was associated with a higher expression of the ILs and expression of IL-17 was higher in epithelium showing hyperkeratosis. The results from the present study showed that the clinical characteristics of OLP and OLL are distinct and can be useful in differentiating these two diagnostic entities. The histological and immunohistochemical features suggest that the studied ILs are more expressed when there is exocytosis of both T CD4+ and T CD8+ lymphocytes. Expression of the ILs can be associated with the epithelial alterations encountered in OLP, participating in the pathogenesis and modulating the expression of the disease.

New methodology for evaluating osteoclastic activity induced by orthodontic load

Orthodontic tooth movement (OTM) is a dynamic process of bone modeling involving osteoclast-driven resorption on the compression side. Consequently, to estimate the influence of various situations on tooth movement, experimental studies need to analyze this cell. Objectives The aim of this study was to test and validate a new method for evaluating osteoclastic activity stimulated by mechanical loading based on the fractal analysis of the periodontal ligament (PDL)-bone interface. Material and Methods The mandibular right first molars of 14 rabbits were tipped mesially by a coil spring exerting a constant force of 85 cN. To evaluate the actual influence of osteoclasts on fractal dimension of bone surface, alendronate (3 mg/Kg) was injected weekly in seven of those rabbits. After 21 days, the animals were killed and their jaws were processed for histological evaluation. Osteoclast counts and fractal analysis (by the box counting method) of the PDL-bone interface were performed in histological sections of the right and left sides of the mandible. Results An increase in the number of osteoclasts and in fractal dimension after OTM only happened when alendronate was not administered. Strong correlation was found between the number of osteoclasts and fractal dimension. Conclusions Our results suggest that osteoclastic activity leads to an increase in bone surface irregularity, which can be quantified by its fractal dimension. This makes fractal analysis by the box counting method a potential tool for the assessment of osteoclastic activity on bone surfaces in microscopic examination. .