Clinicopathological study of oral focal mucinosis: a retrospective case series.

BACKGROUND: Oral focal mucinosis (OFM) is a rare soft tissue lesion of unknown etiology that exhibits tumor-like growth. It is considered the oral counterpart of cutaneous focal mucinosis or cutaneous myxoid cyst. This is a retrospective study of oral OFM diagnosed over a period of 42 years at an oral pathology service. MATERIAL AND METHODS: Clinical, histopathological and immunohistochemical data were analyzed. Alcian blue staining and S-100 immunohistochemistry were performed. RESULTS: Eleven cases were retrieved (4:1 female-to-male ratio). The mean age was 44 years. The gingiva was the most affected site. The main clinical presentation was sessile or pedunculated lesions of fibrous or hyperplasic appearance, most of them asymptomatic. Positive Alcian blue staining and absence of S-100 protein were observed in all specimens, which supported the histological diagnosis of OFM. Surgical excision was the treatment of choice. CONCLUSIONS: Although rare, this study supports the inclusion of OFM in the differential diagnosis of intraoral myxoid lesions.

Apoptosis and cell cycle aberrations in epithelial odontogenic lesions: An evidence by the expression of p53, Bcl-2 and Bax.

BACKGROUND: Ameloblastoma (AMB), odontogenic keratocyst (OKC) and adenomatoid odontogenic tumor (AOT) are epithelial odontogenic lesions with diverse biologic profiles. Defects in regulation of apoptosis and cell cycle may be involved in the development and progression of those lesions, therefore we aimed to investigate the expression of Bcl-2, Bax and p53 to better understand the possible role of these proteins in AMBs, OKCs and AOTs. MATERIAL AND METHODS: The studied sample consisted of 20 AMBs, 20 OKCs and 20 AOTs. Immunohistochemistry technique was performed for the antibodies p53, Bcl-2 and Bax. Immunoreactivity was observed in the epithelial component and positive cells were counted in five fields (100x magnification). Statistical analysis was performed with Kruskal-Wallis and Spearman tests (p <0.05). RESULTS: All lesions exhibited staining for the three studied proteins. There was no statistically significant associations between the expression of proteins and the lesions, however we identified a positive correlation between the expression of p53 and Bcl-2 (r = 0.200) and a negative correlation between p53 and Bax expressions (r = -0.100). In addition, p53 and Bax were similarly expressed between AMBs and OKCs. Bcl-2 was similarly expressed in AMBs and AOTs. CONCLUSIONS: Apoptosis regulatory proteins, as well as cell cycle proteins, are differently expressed in epithelial odontogenic lesions and their expression is possibly related to the biological behavior of AMB, OKC and AOT.

Immunohistochemical evaluation of intermediate filament proteins in squamous papilloma and oral verrucous carcinoma.

OBJECTIVE: Cytokeratins (CKs) are the intermediate filament proteins of the epithelium cells, which have become important markers of normal and abnormal cell differentiation. The goal of the present study was to investigate the expression pattern of CK 10, 13, 14 and 16 in oral verrucous carcinoma (OVC) and oral squamous papilloma (OSP). MATERIAL AND METHODS: Formalin-fixed paraffin-embedded sections from eight cases of each lesion were assessed. Immunohistochemistry was carried out using streptoavidin-biotin complex method. RESULTS: In OVC, CK 10 was expressed in suprabasal to superficial layers whereas in OSP mainly in superficial layer. CK 13 was detected in prickle and superficial cells in most cases of OVC and in suprabasal to superficial cells of OSP. All the cell layers of OVC reacted positively for CK 14 while basal and suprabasal layers of OSP were more pronounced for CK 14. Finally, CK 16 was observed in suprabasal to superficial layer in OVC and the majority cases in OSP showed only superficial reactive cells. CONCLUSIONS: CK 10, 13, 14 and 16 immunohistochemical profile emphasis the biological behavior of the studied lesions and confirm the use of these proteins as markers of differentiation.