Cisto ósseo simples: relatos de casos

Usually diagnosed in routine radiographs, the simple bone cyst occurs infrequently. Etiology is unknown and differential diagnosis has to be made with dentigerous cyst, keratocystic odontogenic tumor, adenomatoid odontogenic tumor, ameloblastoma and central giant cell granuloma. Treatment is surgical, by perforating the cortical bone. In most cases an empty cavity, without any capsule or epithelial covering, is encountered, but it may have a liquid content. Perforation of the mandibular cortical bone elicits a response that results in bone repair of the empty cavity. This article reviews the subject and presents two cases of this entity and discusses the possible factors that could interfere in healing course.

Immunohistochemical expression of Rho GTPases in ameloblastomas

Rho GTPases are proteins that regulate cell cycle, shape, polarization, invasion, migration, and apoptosis, which are important characteristics of normal and neoplastic cells. Rho GTPases expression has been reported in normal tooth germ and several pathologies; however, it has not been evaluated in ameloblastomas. The aim of this study was to analyze the expression and distribution of RhoA, RhoB, Rac1, and Cdc42 Rho GTPases in solid and unicystic ameloblastomas. Three-micrometer sections from paraffin- embedded specimens were evaluated by using an avidin- biotin immunohistochemical method with antibodies against the proteins mentioned above. RhoA and RhoB staining was observed in a high number of cells (P < 0.05) and greater intensity in non-polarized ones. Rac1 was not observed, andCdc42 didnot showany statistical differences between the number of non-polarized and basal positive cells (P > 0.05). Upon comparing the studied ameloblastomas, a higher number of positive cells in the unicystic variant was observed than that in the solid one (P < 0,05). The results obtained suggest that theseGTPases could play a role in the ameloblastoma neoplastic epithelial cell phenotype determination (polarized or non-polarized), as well as in variant (solid or unicystic) and subtype (follicular or plexiform) determination. Furthermore, they could participate in solid ameloblastoma invasion mechanisms. J Oral Pathol Med (2012) 41: 400-407

Is podoplanin expression associated with the proliferative activity of ameloblastomas?

Oral Diseases (2012) 18, 673679 Objectives: The aim of this study was to investigate the relationship between podoplanin expression and proliferative activity of ameloblastomas and remnants of the odontogenic epithelium from dental follicles (DF) of unerupted teeth. Subjects and methods: Thirty-three paraffin-embedded ameloblastomas and thirty-two DF obtained of unerupted teeth were analyzed by immunohistochemistry using anti-human podoplanin and anti-Ki-67 antibodies. Podoplanin expression in odontogenic epithelial cells was evaluated using a scoring method, and the Ki-67 labeling index was determined by the percentage of positive odontogenic cells. Results: All ameloblastomas displayed podoplanin expression in ameloblast-like cells of the epithelial islands. Membranous expression of podoplanin in ameloblastomas was stronger than in the remnants of odontogenic epithelium (P = 0.001). Statistically significant difference was observed between the cytoplasmic and membranous expression of podoplanin in the remnants of odontogenic epithelium (P = 0.001). The index of epithelial odontogenic proliferative activity, verified by Ki-67 expression, was higher in ameloblastomas vs remnants of odontogenic epithelium (P < 0.001). No statistically significant correlation was identified between podoplanin and the cellular odontogenic proliferative activity in ameloblastomas and DF (P > 0.05). Conclusions: These results provide evidence that there is no connection between podoplanin immunostaining and odontogenic cellular proliferative activity and suggest a role for membranous podoplanin expression in the local invasion of ameloblastomas.

Keratocystic odontogenic tumors and Carnoy's solution: results and complications assessment

Oral Diseases (2012) 18, 548557 Objective: Keratocystic odontogenic tumors (KOTs) can be treated with Carnoys solution, although this treatment modality is not free from complications. It is important to verify the incidence of complications after the use of Carnoys solution and compare these with the literature. Materials and methods: This study verified the effects of a complementary treatment for KOTs and assessed the incidence of such complications as recurrence, infection, sequestrum formation, mandibular fracture, dehiscence, and neuropathy. Results: Twenty-two KOTs treated with Carnoys solution combined with peripheral ostectomy were included, and the follow-up period varied from 12 to 78 months with a mean of 42.9 months. Complications included recurrence (4.5%), dehiscence (22.7%), infection (4.5%), and paresthesia (18.2%). No difference was found among lesions associated (9.1%) or not (0%) with nevoid basal cell carcinoma syndrome (P > 0.05). Dehiscence was influenced by marsupialization (P < 0.05), and paresthesia was observed exclusively in cases of mandibular canal fenestration (P < 0.01). Conclusions: Complementary treatment with Carnoys solution and peripheral ostectomy appear to provide efficient treatment for KOTs. Complications originating from the use of the solution are less frequent and less serious than complications associated with cryotherapy. Neuropathy seems to be related to direct contact between the solution and the epineurium.

Matrix metalloproteinases, tissue inhibitors of metalloproteinases, and growth factors regulate the aggressiveness and proliferative activity of keratocystic odontogenic tumors

Objective. The objective of this preliminary study was to evaluate the expression of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs) and growth factors in keratocystic odontogenic tumors (KOTs). Study Design. The expression of MMPs, TIMPs, growth factors, and the extracellular signal-regulated kinase (ERK) 1/2 signaling pathway were assessed by immunohistochemistry in 15 cases of KOT and 4 cases of calcifying cystic odontogenic tumor (CCOT). Results. KOT samples expressed significantly higher amounts of MMPs, TIMPs, growth factors, epidermal growth factor receptor (EGFR), and ERK compared with CCOT samples, with the exception of MMP-2 and TIMP-1. Conclusions. MMP-9, TIMP-2, EGF and transforming growth factor alpha act together and likely regulate the proliferation and aggressiveness of KOT. ERK-1/2 serves as the transducer of signals generated by these proteins, which signal through the common receptor, EGFR. This process may be related to the increased proliferation and aggressiveness observed in KOT. (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:487-496)

[The "globulomaxillary cyst" a specific entity or a myth?]

The following review investigates the term and concept of the globulomaxillary cyst as a correct clinico-pathological diagnosis to describe a so-called fissural cyst said to be caused by epithelial entrapment between the nasal and maxillary process. After analyzing the available literature it has to be concluded that neither from an embryologic nor from a clinical or pathohistological standpoint the term globulomaxillary cyst represents a real entity by itself. Therefore, globulomaxillary cysts have to be diagnosed alternatively after a thorough clinical, radiological and histological examination as other odontogenic cysts like dentigerous cysts or odontogenic keratocysts, odontogenic tumors like ameloblastoma, central giant cell tumors, solitary bone cysts, etc.

Avaliação imuno-histoquímica das proteínas BMP-4, FGF-8 e Sindecan-1 em tumores odontogênicos

The development and progression of odontogenic tumors have been associated with an imbalance in the activity of growth factors, adhesion molecules, extracellular matrix proteins and their degradation enzymes, angiogenic factors and osteolytic. Some studies have shown that interaction relationships inductive epithelial / mesenchymal determinants of Odontogenesis are mimicked by these tumors. The objective of this research was to investigate the immunolocalization of growth factors (BMP-4 and FGF-8) and Sindecan-1 structural protein in a series of odontogenic tumors presenting different biological behaviors, to contribute to a better understanding of the role of these proteins in tumor development. The sample consisted of 21 of the solid ameloblastoma, odontogenic keratocysts 19 and 14 odontogenic adenomatoid tumors. Increased Sindecan-1 immunostaining was seen in the epithelium of the lesions when compared with mesenchyme. In ameloblastoma and odontogenic keratocysts, this expression was higher than in AOT. Epithelial expression of BMP4 showed quantitatively similar in the three studied lesions; however, when anlisada mesenchymal immunoreactivity, was detected significant higher expression when compared to the ameloblastoma keratocysts. In ameloblastoma, mesenchymal expression was predominantly (p = 0.008), while in keratocyst higher expression in the epithelium was observed (p = 0.046). In all injuries, strong or moderate correlation was observed in the BMP-4 immunoreactivity in the epithelium and mesenchyme. FGF-8, no injury was observed difference between the immunoreactivity in the epithelium or mesenchyme, however in ameloblastoma positive correlation was found (Spearman correlation, rho = 0.857, p <0.001). The results of this study suggest that the three evaluated biomarkers actively involved in the pathogenesis of lesions, especially the expression of ameloblastomas indicating a strong interaction between parenchymal and stromal cells which may contribute to its marked aggressiveness.

Análise da imunoexpressão de Oct- 4 e C44 em lesões odontogênicas epiteliais benignas

benign epithelial odontogenic lesions are great clinical importance entities that develop in the jaws from the tissues that form teeth. It has been shown that in benign and malignant tumors, are present in a large number of tumor stem cells, which has great implications in the development of these lesions. Oct-4 and CD44 have been demos as important markers for tumoral stem cells. The objective of this study was to identify epithelial cells expressing stem cell markers by immunohistochemical expression of Oct-4 and CD44 in a series of cases of benign epithelial odontogenic lesions. The sample was comprised of 20 cases of odontogenic keratocyst (OKC), 20 cases of solid/multicystic ameloblastoma and 20 cases of adenomatoid odontogenic tumor (AOT). The expression of Oct-4 and CD44 was evaluated in epithelial lesions using the percentage of positive cells (PP) and the intensity of expression (IE), being realized the sum of these scores, resulting in Total Immunostaining Score (TIS) ranging 0 to 7. The results were submitted to the appropriate statistical test (nonparametric Kruskal-Wallis and Spearman correlation coefficient). All cases were positive for both markers and most showed high expression of both markers. The analysis of Oct-4 expression revealed no statistically significant differences (p = 0.406) among the studied lesions. Regarding the CD44 expression, there was a statistically significant difference between the cases of ameloblastoma and TOA in relation to the CCO, with the latter show more cases in the score 7 (p = 0.034). In the correlation analysis of the immunoreactivity of both markers in the three lesions studied, there was no statistically significant correlation. The results of this study identified the presence of cells with stemness characteristics arranged at various sites in the epithelial component of the studied lesions suggesting their possible role in the histogenesis and differentiation in benign epithelial odontogenic lesions, thus contributing to the development of these lesions.

Análise da imunoexpressão de Oct- 4 e C44 em lesões odontogênicas epiteliais benignas

benign epithelial odontogenic lesions are great clinical importance entities that develop in the jaws from the tissues that form teeth. It has been shown that in benign and malignant tumors, are present in a large number of tumor stem cells, which has great implications in the development of these lesions. Oct-4 and CD44 have been demos as important markers for tumoral stem cells. The objective of this study was to identify epithelial cells expressing stem cell markers by immunohistochemical expression of Oct-4 and CD44 in a series of cases of benign epithelial odontogenic lesions. The sample was comprised of 20 cases of odontogenic keratocyst (OKC), 20 cases of solid/multicystic ameloblastoma and 20 cases of adenomatoid odontogenic tumor (AOT). The expression of Oct-4 and CD44 was evaluated in epithelial lesions using the percentage of positive cells (PP) and the intensity of expression (IE), being realized the sum of these scores, resulting in Total Immunostaining Score (TIS) ranging 0 to 7. The results were submitted to the appropriate statistical test (nonparametric Kruskal-Wallis and Spearman correlation coefficient). All cases were positive for both markers and most showed high expression of both markers. The analysis of Oct-4 expression revealed no statistically significant differences (p = 0.406) among the studied lesions. Regarding the CD44 expression, there was a statistically significant difference between the cases of ameloblastoma and TOA in relation to the CCO, with the latter show more cases in the score 7 (p = 0.034). In the correlation analysis of the immunoreactivity of both markers in the three lesions studied, there was no statistically significant correlation. The results of this study identified the presence of cells with stemness characteristics arranged at various sites in the epithelial component of the studied lesions suggesting their possible role in the histogenesis and differentiation in benign epithelial odontogenic lesions, thus contributing to the development of these lesions.

Immunohistochemical expression of E-cadherin and beta-catenin in ameloblastomas and tooth germs

OBJECTIVE: The aim was to analyze the expression of E-cadherin and beta-catenin in ameloblastomas and tooth germs to determine their roles in cell differentiation processes and invasiveness compared with odontogenesis. STUDY DESIGN: Twenty-one ameloblastoma cases (16 solid and 5 unicystic tumors) and 5 tooth germs were submitted to the immunohistochemical detection of E-cadherin and beta-catenin. Immunoreactivity was evaluated using descriptive and semiquantitative analysis, investigating the location and intensity of staining. The Fisher exact test was performed, and P values of <.05 were considered to indicate statistical significance. RESULTS: There was no statistically significant difference in the expression of E-cadherin and beta-catenin between solid and unicystic ameloblastomas (P = .59; P = .63; respectively). The same was found when comparing solid and unicystic ameloblastomas with the tooth germs for both E-cadherin (P = .53; P = .44; respectively) and beta-catenin (P = .12; P = .16; respectively). Nuclear staining of beta-catenin was observed in only 4 cases (3 solid and 1 unicystic tumor). CONCLUSION: The results showed no differences in the expression of E-cadherin or beta-catenin between tooth germs and solid and unicystic ameloblastomas. The expression of these molecules seems mainly to be related to the process of cell differentiation.