LCs and MCs are known to be directly influenced by UV radiation. This study investigated the presence of Langerhans cells (LCs) and mast cells (MCs) in actinic cheilitis (AC) exhibiting epithelial dysplasia (ED). Using immunohistochemistry for CD1a and mast cell tryptase, LCs and MCs density was assessed in 35 cases of AC with different degrees of ED. LCs were found in 32 cases of AC whereas MCs were found in all cases. There was an increase in LCs density irrespective of degree of ED when the cases were compared to normal lip mucosa (P = 0.04343). No statistical difference in LCs density was observed regarding the different degrees of dysplasia (P > 0.05). Significant difference in MCs density between mild and moderate dysplasia and normal lip mucosa was found (P < 0.05). No significant correlation between LCs and MCs was seen (P = 0.1258). Although no correlation could be established between LCs and MCs and the different degrees of ED; it is possible that the accumulation of LCs plays an immunostimulatory and protective role in the defense against progression of dysplasia. Further studies are necessary to determine the role of MCs in the development of AC.

SUMMARY:The extracellular matrix (ECM) plays an important role in the regulation of biological events such as the development of cell migration, proliferation and differentiation. Chronic sun exposure causes changes present in the ECM of actinic cheilitis (AC), a premalignant lesion of the lower lip which helps to understand the carcinogenesis of the lip. This study aimed to investigate elastin, the main component of solar elastosis alternating current in an attempt to establish the relationship between this protein and ECM in epithelial dysplasia. Paraffin embedded tissue sections of the lesions of 35 cases of AC were analyzed by immunohistochemistry for elastin, and became the association with the degree of epithelial dysplasia and age. Highest scores of elastin (+3) was predominant in 45.7% of cases of AC, especially in cases of severe dysplasia (n = 3). When comparing the scores of elastin between the different grades of epithelial dysplasia showed no significant difference (P> 0.05, Kruskal-Wallis). This study was not able to demonstrate the influence of elastin on the severity of epithelial dysplasia in AC. Additional studies on other ECM proteins must be conducted in an attempt to better understand the mechanism of malignant progression of the AC.

A queilite actínica (QA) apresenta-se como uma lesão difusa do vermelhão do lábio inferior, resultante da exposição à radiação solar excessiva, podendo exibir alterações histomorfológicas indicativas de desvios da diferenciação normal. Histologicamente, a característica principal da pele que exibe fotoenvelhecimento é o acúmulo do material basofílico, amorfo, rico em fibras elásticas, denominada elastose solar. Esse aspecto é demonstrado pelas lesões de QA, no entanto, a maioria dos pesquisadores estuda o tecido conjuntivo da pele normal e (ou) exposta, deixando de lado as lesões labiais provocadas por danos actínicos, como é o caso da QA. O objetivo deste trabalho é estudar o grau de displasia e o padrão de organização das fibras colágenas e elásticas nas lesões de queilite actínica. Através das técnicas de rotina, Picrossirius e orceína de Weigert foram estudados respectivamente, o grau de displasia e o padrão de organização das fibras colágenas e elásticas dessa lesão. Dos aspectos clínicos, evidenciou-se uma maior freqüência das lesões de QA no sexo masculino, e a faixa etária atingiu predominantemente a quinta década de vida. Histopatologicamente, seis casos exibiram displasia discreta, quatro exibiram displasia moderada e três, displasia intensa. Na matriz extracelular, foi observada a ausência de fibras colágenas nas áreas correspondentes à elastose solar. Nessas áreas, as fibras colágenas foram substituídas por fibras elásticas, provavelmente dando origem ao acúmulo de material semelhante à elastina, característica das lesões de queilite actínica. Tendo em vista que a matriz extracelular pode influenciar os processos de invasão e migração celulares, a participação desses componentes torna-se importante, uma vez que a queilite actínica é passível de transformação maligna.