The aim of study was to evaluate the clinicopathological features of oral mucoceles and the immunohistochemical expression of cellular and extracellular matrix components in these lesions. One hundred cases of oral mucoceles were examined for clinicopathological features. The expression of mast cell tryptase, CD68, MMP-1 (matrix metalloproteinase-1), MMP-9 (matrix metalloproteinase-9) and CD34 was investigated immunohistochemically in 32 cases. The lesions arose as nodules or blisters of variable color. The mean age was 23.2 years and a higher male frequency was observed. The most common locations were the lower lip (92%), followed by the floor of the mouth (7%), and palate (1%). The lesion size ranged from 0.4 to 3.0cm. Unusual histopathological findings as superficial mucoceles (n=16, 16%), pseudopapillary projections (n=3, 3%), epithelioid histiocytes (n=4, 4%), multinucleated giant cells (n=1, 1%) and myxoglobulosis (n=9, 9%) were also seen. Mast cells and CD68-positive macrophages, MMP-1, MMP-9 and CD34-positive blood vessels were seen in all cases. A significant association was seen between mast cells and MMP-1 (p=0.03) and between macrophages and MMP-1 (p=0.01). This study provided important insight into the demographic and histopathological occurrence of oral mucoceles. The tissue remodeling seen in these lesions mainly involved the migration and interaction of mast cells, macrophages and MMP-1.

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.

ABSTRACT:The radiographic features of an intraosseous lesion are usually associated with the biological behavior of the tumor. In view of the fact that the growth and behavior of keratocystic odontogenic tumors (KCOT) is mainly associated with the proliferation of the cystic epithelium, the objective of the present study was to evaluate the relationship between cell proliferation markers and radiographic features of this tumor. Thirty-seven radiographs of KCOT obtained from 30 patients were scanned and evaluated on a monitor. Sections were submitted to immunohistochemistry for Ki-67, p63, and p53 proteins on an EnVision™ system. Thirty-one KCOTs were observed in the posterior of the mandible, and the unilocular aspect was predominant (n= 26). Nineteen KCOTs distorted the mandibular canal and 11 displaced teeth. Satellite cysts were associated with a multilocular aspect (P= 0.016). p53 was in KCOTS with diffuse margins (p=0.049), p63 with NBCCS (p=0.049) KOT and higher KI-67 positive cells was observed in KCOTs presenting distortion of the mandibular canal (p=0.042). The distribution of Ki-67, p63, and p53 positive cells was similar between KCOTs with uni-and multilocular aspects. The results of the present study suggest that cell proliferation in KCOT contributes to the radiographic features of this tumor.

Despite the results of this study being similar to previous reports found in the literature, it provides an important insight about keratocystic odontogenic tumours in a Brazilian population.