A comparative study of epithelial cell proliferation between the odontogenic keratocyst, orthokeratinized odontogenic cyst, dentigerous cyst, and ameloblastoma

Evaluation of the Connective Tissue Wall in Sporadic Cases of Keratocystic Odontogenic Tumor (KCOT) Using MMP-9 and Confocal Microscopy: A Retrospective Study

Background:

Keratocystic odontogenic tumor (KCOT) is an odontogenic lesion which manifests distinct biological behavior. Predominant studies in KCOT attribute this behavior to high epithelial proliferative capacity. Besides, a few studies facet loosely arranged collagen can contribute to the behavior of KCOT. Matrix metalloproteinases (MMP) are enzymes that degrade extracellular matrix components under both physiologic and pathologic conditions. The loosely arranged collagen in connective tissue wall of KCOT could be related to the degree of MMP-9 expression.

Aim:

To evaluate the arrangement of collagen fibers along with immunoexpression of MMP-9 and to relate to its neoplastic biologic behavior in sporadic cases of KCOT.

Materials and Methods:

KCOT ( n = 23) and dentigerous cyst (DC) ( n = 15) samples were processed for the following techniques: Masson’s trichrome stain for light microscopy, PMA-PSR stain for confocal microscopy, and MMP-9 for immunohistochemistry.

Results:

In Masson’s trichrome analysis, correlation of collagen fiber arrangement in the deeper regions with color intensity for KCOT was found to be statistically significant ( P = .033). In confocal microscopy, there was no difference between intensities in KCOT ( P = .990) and DC ( P = .233), respectively. The immunoexpression of MMP-9 in the connective tissue wall of DC (73.3%) was relatively higher than that of KCOT (60.8%). However, on comparison between KCOT and DC in the presence of inflammation, the immunoexpression of MMP-9 was higher in DC (100%) than KCOT (69.9%) and was statistically significant ( P = .028).

Conclusion:

It was concluded that the loose connective tissue wall in KCOT is because of the inherent nature of the lesion that could facilitate its biologic behavior. If inflammation is present, this could further aggravate the tumorigenic behavior.

Changes in Cellular Regulatory Factors before and after Decompression of Odontogenic Keratocysts

Decompression followed by enucleation, which is one of the treatments used for odontogenic keratocysts (OKCs), is frequently used in OKC lesions of large sizes. This method offers the advantage of minimizing the possibility of sensory impairment without creating a wide-range bone defect; moreover, the recurrence rate can be significantly lower than following simple enucleation. This study aimed to assess the changes in histology and expression of proliferation markers in OKCs before and after decompression treatment. A total of 38 OKC tissue samples from 19 patients who had undergone decompression therapy were examined morphologically and immunohistochemically to observe changes in proliferative activity before and after decompression. The markers used for immunohistochemistry (IHC) staining were Bcl-2, epidermal growth factor receptor (EGFR), Ki-67, P53, PCNA, and SMO. The immunohistochemistry positivity of the 6 markers was scored by using software ImageJ, version 1.49, by quantifying the intensity and internal density of IHC-stained epithelium. The values of Bcl-2, Ki-67, P53, proliferating cell nuclear antigen (PCNA), and SMO in OKCs before and after decompression showed no significant change. No correlation between clinical shrinkage and morphologic changes or expression of proliferation and growth markers could be found. There was no statistical evidence that decompression treatment reduces potentially aggressive behavior of OKC within the epithelial cyst lining itself. This might indicate that decompression does not change the biological behavior of the epithelial cyst lining or the recurrence rate.

Clinical and Cone-Beam Computed Tomography Features of Orthokeratinized Odontogenic Cysts and Odontogenic Keratocysts in the Mandible

PURPOSE

The aim of the study was to compare the clinical and cone-beam computed tomography features of orthokeratinized odontogenic cysts (OOCs) and odontogenic keratocysts (OKCs) and to fully understand features of these 2 odontogenic cysts.

MATERIALS AND METHODS

This retrospective cross-sectional study included patients with mandibular OOCs and OKCs. The predictor variables included age at the time of diagnosis, sex, anatomical location of the cysts, lesion size, cortical bone expansion rate, and presence of cortical bone destruction, impacted tooth, tooth displacement, and root resorption. The outcome variable was the type of cystic lesion. A 1-way analysis of variance test was used to analyze the differences among the cases of OOCs and OKCs. The specificity and sensitivity of the radiological features were calculated to differentiate OOCs from OKCs.

RESULT

The sample was composed of 12 patients with OOCs and 36 patients with OKCs. The mean ages of the patients with OOCs (30.50 ± 6.14 years) and OKCs (38.39 ± 19.44 years) were concentrated in the third decade. The cystic lesions occurring in areas II and III accounted for 66.67 and 52.78% of the OOC and OKC cases, respectively. The cortical bone expansion rate of the OOC was larger than that of the unilocular OKC (OOC, 2.20 ± 1.05; OKC, 1.48 ± 0.50; P < .05). The specificity and sensitivity of unilocular or multiocular cysts to differentiate OOC from OKC were 100%, 42%, 95% confidence interval of 0.1479 to 0.3892 (P < .05) and tooth displacement were 100%, 3%, 95% confidence interval of 0.1479 to 0.3892 (P < .05).

CONCLUSIONS

The results of this study suggest clinical and radiological features of OOCs and OKCs mostly overlap, but OOC has distinctive characteristics. Most cystic lesions of OOC are unilocular cysts, rarely accompanied by tooth displacement. The cortical bone expansion rate is larger than that of unilocular cysts of OKC.

Maspin, Syndecan-1, and Ki-67 in the Odontogenic Keratocyst: An Immunohistochemical Analysis

The odontogenic keratocyst (OKC) is a controversial lesion that was reclassified as a tumor with the name “keratocystic odontogenic tumor” in 2005. The reclassification was revoked recently in 2017, with a conclusion on the need for further studies on the subject. In this study, the expressions of an important regulatory protein (maspin), an important integral membrane proteoglycan (syndecan-1), and a universal proliferation marker (Ki-67) in the epithelium of the OKC were investigated in comparison with the dentigerous cyst (DC) and ameloblastoma (AB). Twenty-six OKCs, eleven DCs, and ten conventional ABs were immunohistochemically stained for maspin, syndecan-1, and Ki-67. ImageJ was used to analyze the positivity of maspin and syndecan-1. The Ki-67 score was calculated as the percentage of positive nuclei in 5 high power fields. Analysis of variance (ANOVA) test and Student t-test were used as appropriate. Lower expressions of maspin were noted in OKC and DC compared to those in AB, and lower expressions of syndecan-1 were noted in OKC and AB compared to those in DC. The differences, however, did not reach statistical significance (ANOVA and t-test: P > 0.05). The Ki-67 score was significantly higher in OKC than in DC (t-test: P < 0.05), and not significantly different from AB (t-test: P > 0.05). In conclusion, expressions of maspin and syndecan-1 are not strongly representative of differences in behavior between OKC, AB, and DC. However, the expression of Ki-67 indicates comparable proliferative activities of OKC and AB, which are higher than that of DC. Further investigation on the biologic behavior of OKC is still recommended to arrive at more specific conclusions regarding its classification.

Shark tooth regeneration reveals common stem cell characters in both human rested lamina and ameloblastoma

The human dentition is a typical diphyodont mammalian system with tooth replacement of most positions. However, after dental replacement and sequential molar development, the dental lamina undergoes apoptosis and fragments, leaving scattered epithelial units (dental lamina rests; DLRs). DLRs in adult humans are considered inactive epithelia, thought to possess limited capacity for further regeneration. However, we show that these tissues contain a small proportion of proliferating cells (assessed by both Ki67 and PCNA) but also express a number of common dental stem cell markers (Sox2, Bmi1, β-catenin and PH3) similar to that observed in many vertebrates that actively, and continuously regenerate their dentition. We compared these human tissues with the dental lamina of sharks that regenerate their dentition throughout life, providing evidence that human tissues have the capacity for further and undocumented regeneration. We also assessed cases of human ameloblastoma to characterise further the proliferative signature of dental lamina rests. Ameloblastomas are assumed to derive from aberrant lamina rests that undergo changes, which are not well understood, to form a benign tumour. We suggest that dental lamina rests can offer a potential source of important dental stem cells for future dental regenerative therapy. The combined developmental genetic data from the shark dental lamina and ameloblastoma may lead to the development of novel methods to utilise these rested populations of adult lamina stem cells for controlled tooth replacement in humans.

A Novel Citrullinated Modification of Histone 3 and Its Regulatory Mechanisms Related to IPO-38 Antibody-Labeled Protein

IPO-38 is a potential biomarker for early diagnosis of gastric cancer that we recently identified. Although we characterized its chemical nature as a nucleosome histone, we suspected the existence of histone modification for the IPO-38 antibody-labeled protein. Here, we used a commercially available modified histone peptide array to identify the type and site of histone modification labeled by the IPO-38 monoclonal antibody. In protein array analysis, the citrulline modification of histone 3 on arginine 26 (H3R26Cit) yielded the strongest signal. Although peptidyl arginine deiminase-2 and -4 (PADI2 and PADI4, respectively) can catalyze the conversion of arginine to citrulline, we observed that only PADI4 expression correlated with the citrulline histone modification of H3R26Cit. Overexpression of PADI4, via transfection of a eukaryotic expression vector, and knockdown of PADI4 gene expression, by a PADI4 CRISPR/Cas9 vector, confirmed the crucial function of PADI4 on the increased level of H3R26Cit in gastric cancer cell lines. By immunoprecipitation and immunoblotting, we found an interaction between H3R26Cit and H3K27me3. Our study established the first link between the IPO-38 antigen and citrullinated histone 3, and clarified the upstream regulatory enzyme PADI4. The new findings suggest an important role for the citrullination modification of histone in gastric cancer biology, and should help us optimize the development of a sensitive and specific diagnostic reagent.

Orthokeratinized odontogenic cyst (OOC): Clinicopathological and radiological features of a series of 10 cases

BACKGROUND

Orthokeratinized Odontogenic Cyst (OOC) is a rare, developmental odontogenic cyst which was considered in the past to be a variant of Odontogenic keratocyst (OKC) later renamed as keratocystic odontogenic tumor (KCOT). The treatment of OOC is by enucleation and the prognosis, following enucleation is excellent with a recurrence rate of less than 2%. On the other hand, OKC has a recurrence rate between 8 and 25% after enucleation. Thus it is important to differentiate between the two entities.

METHODS

All cases reported in our section as OOC during the period 2013 to 2018 were retrieved from the surgical pathology files and slides were reviewed by the authors. All cases which met the histological criteria for OOC were included.

RESULTS

A total of 10 cases were included. 70% patients were males, ages ranged from 23 to 60 years, with mean age of 38.9 years. 70% of cases were located in the mandible and 90% patients presented with swelling. Radiologically, 90% cases were unilocular, all were radiolucent lesions. Mean size was 4.0 cm. Histologically, all cases demonstrated the classic microscopic features. Follow-up was available in 8 patients. All were treated by enucleation. All 8 were alive with no recurrences over a follow-up period ranging from 7 to 62 months.

CONCLUSIONS

OOC has a better prognosis than OKC and needs to be differentiated from OKC due to differences in treatment and prognosis. Large majority of our cases presented with swelling and occurred in the mandibles of young males. All were radiolucent and most were unilocular. All were treated by enucleation and no recurrences occurred over follow up period ranging up to 62 months. Our findings were similar to those described in other published series.

An Analysis of Dentigerous Cysts Developed around a Mandibular Third Molar by Panoramic Radiographs

Dentigerous cysts are one of the most prevalent types of odontogenic cysts and are associated with the crown of an unerupted tooth, especially of the mandibular third molar. In this study, the characteristics of a dentigerous cyst developed around a mandibular third molar on panoramic radiographs were investigated. The panoramic images of 257 consecutive dentigerous cyst cases associated with a mandibular third molar were analyzed. The mean age of the patients was 45.9 ± 13.3 years. The size of the cyst did not significantly correlate to the age of the patient. The unilocular type (89.1%) and the crown side type (68.5%) were significant. The associated mandibular third molars had a high frequency of class III (64.6%) and position B (48.3%) in Pell and Gregory classification and of horizontal position (36.3%) in angulation. Dentigerous cysts were thought to originate and grow commonly around deeply impacted third molars. The associated third molar with dentigerous cyst tends to have a mesial inclination. Dentigerous cysts do not appear to develop gradually after the crown formation has finished, but arise at various periods randomly.

MCM3 and Ki67 proliferation markers in odontogenic cysts and ameloblastoma

Background

MCM3 is a marker of proliferation that has been used as a diagnostic or prognostic marker in many pathologic lesions.

Purpose

The purpose of this study is to investigate the proliferative activity of dentigerous cysts, odontogenic keratocyst and ameloblastoma using minichromosome maintenance 3 (MCM3) and compare it with Ki-67 proliferation marker.

Methods

In this cross-sectional study, 40 cases including 11 cases of dentigerous cyst, 14 odontogenic keratocyst, and 15 ameloblastoma were included. Immunohistochemical expression of MCM3 and Ki-67 were investigated and compared statistically using ANOVA, Chi-square, Tukey and Spearman's correlation tests.

Results

All subjects were positive for Ki-67 and MCM3. There was a significant difference in MCM3 and Ki-67 expression among all groups. Compared to Ki-67, MCM3 exhibited a higher level of expression. Ameloblastoma and odontogenic keratocyst revealed higher expression rate of both markers in comparison to dentigerous cysts.

Conclusion

The results showed MCM3 and Ki67 expression in the most common odontogenic cysts and tumors, especially more aggressive lesions. MCM3 might have a role in pathogenesis of these lesions and could be a reliable marker for assessing proliferation activity.

Oct-4 and CD44 in epithelial stem cells like of benign odontogenic lesions

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 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 demonstrated as important markers for tumoral stem cells. The aim of this study was investigate the presence of stem cell markers Oct-4 and CD44 in benign epithelial odontogenic lesions. Twenty odontogenic keratocysts (OKC), 20 ameloblastomas (AMB) of the solid/multicystic type and 20 adenomatoid odontogenic tumors (AOT) were retrospectively analyzed for immunohistochemical detection of Oct-4 and CD44 in their epithelial component. All cases were positive for the two markers, with the majority exhibiting a high expression. Analysis of the expression of Oct-4 revealed no statistically significant differences (p = 0.406) between the lesions studied. Regarding CD44, there was a significant difference between the cases of AMB and AOT in relation with OKC, with the latter presenting a greater labelling (p = 0.034). No statistically significant correlation between Oct-4 and CD44 was observed in the lesions. In our findings, the presence of stem cell-like phenotype at various sites of the epithelial component of the odontogenic lesions was identified, suggesting its possible participation in histogenesis and differentiation without, however, exerting influence on the aggressiveness of the lesions.

Potential involvement of chondroitin sulfate A in the pathogenesis of ameloblastoma

Ameloblastoma is classified as a benign odontogenic tumor characterized by locally invasive behavior and high risk of recurrence. Here, we evaluate a potential role for glycosaminoglycan, a structural component of cell membranes and extracellular matrix, in ameloblstoma pathogenesis. We subjected formalin-fixed, paraffin-embedded tissue sections of 34 cases of ameloblastoma, 10 of odontogenic keratocyst, and 17 of dentigerous cyst to immunohistochemistry using monoclonal antibodies recognizing chondroitin sulfate A (CS-A), heparan sulfate (HS), and keratan sulfate (KS). Expression levels of CS-A in epithelial component and stroma of ameloblastoma were significantly higher than those in odontogenic keratocyst and dentigerous cyst. Moreover, CS-A in ameloblastoma was more strongly expressed in stellate reticulum-like cells than in amelobast-like cells with statistical significance. On the other hand, expression levels of HS and KS in epithelial component and stroma of ameloblastoma were lower compared with CS-A. These results overall reveal that among these odontogenic lesions, CS-A is preferentially expessed in ameloblastoma, suggesting potential pathogenetic role probably in cytodifferention of tumor cells to stellate reticulum-like cells.

Role of HIF-1α and CASPASE-3 in cystogenesis of odontogenic cysts and tumors

OBJECTIVES

Odontogenic cysts and tumors are the most relevant lesions that affect the gnathic bones. These lesions have in common the formation of cystic areas and this common feature may suggest involvement of similar mechanisms. The hypoxia inducible factor 1 alpha (HIF-1α), a responsive protein to hypoxia and caspase-3, an irreversible apoptosis marker, may contribute to cyst formation. Thus, this study aimed to investigate the immunoexpression of these proteins in odontogenic cysts and tumors.

MATERIAL AND METHODS

Twenty cases of ameloblastoma, keratocystic odontogenic tumor (KOT) (n = 20), radicular cyst (RC) (n = 18), dentigerous cyst (DC) (n = 11), calcifying cystic odontogenic tumor (n = 8), and dental follicle (DF) (n = 10) were used to investigate HIF-1α and caspase-3 expression in sequential serial cuts by immunohistochemistry.

RESULTS

HIF-1α was overexpressed in RC, DC, and ameloblastoma when compared with DF. The basal and sometimes the lower suprabasal layer showed no or very low expression in DC, KOT, and ameloblastoma, the last also showing strong expression in solid epithelial areas and initial cystic formation regions. Caspase-3 was found to be overexpressed in all lesions, with the highest expression in odontogenic cysts compared to tumors. HIF-1α and caspase-3 were localized in similar areas of the same lesions, especially in the epithelium surrounding cystic formations.

CONCLUSIONS

This study showed distinct immunoexpression of HIF-1α and caspase-3 in odontogenic cyst and tumors, with higher expression observed in odontogenic cysts.

CLINICAL RELEVANCE

These findings suggest a possible correlation between hypoxia, apoptosis, and cystogenesis, leading to understand the mechanisms responsible to cystic formation in odontogenic lesions.

Expression of Vascular Endothelial Growth Factor in Odontogenic Cysts: Is There Any Impression on Clinical Outcome?

Background:

The recent scientific reports have shown that angiogenesis can affect biological behavior of pathologic lesions.

Objective:

Regarding unique clinical outcome of Odontogenic keratocyst (OKC), the present study was aimed to compare angiogenesis in Odontogenic keratocyst and Dentigerous cyst (DC).

Method:

In this experimental study, tissue sections of 46 samples of OKC and DC were stained through immunohistochemical method using Vascular Endothelial Growth Factor (VEGF) antibody. VEGF expression was evaluated in epithelial cells, fibroblasts and endothelial cells. The average percentage of stained cells in any samples was categorized to 3 groups as follows: SCORE 0: 10% of cells or less are positive. SCORE 1: 10 to 50% of cells are positive. SCORE 2: more than 50% of cells are positive. Mann-U-Whitney, T-test and chi-square was used for statistical analysis.

Result:

The average of VEGF expression in 24 samples of DC was 20.2% and in 22 samples of OKC was 52.6%, respectively. The average of VEGF expression in these two cysts had statistical significant differences. (PV= 0.045). There was significant statistical differences between two cysts in the terms of VEGF SCORE (PV= 0.000). OKC samples had significantly higher SCORE for the purpose of VEGF incidence than DC. Also, there were no differences between VEGF expression in epithelial cells of two cysts (PV= 0.268) there were significant statistical differences between two cysts in terms of endothelial cell staining. The endothelial cell staining was significantly higher in OKC than DC (PV= 0.037%).

Conclusion:

Regarding higher expression of Vascular Endothelial Growth factor in OKC than DC, it seems that angiogenesis may have great impression on clinical outcome of OKC.

Odontogenic epithelial proliferation is correlated with COX-2 expression in dentigerous cyst and ameloblastoma

Investigation of cyclooxygenase (COX)-2 in dentigerous cyst and ameloblastoma may help to improve understanding of the nature and behavior of odontogenic cysts and tumors, and in addition may eventually represent a definitive target for a pharmacological approach in the management of these lesions. The aim of this study was to evaluate COX-2 expression and its correlation with the proliferation of odontogenic epithelium in these lesions. Dentigerous cysts (n=16) and ameloblastomas (n=17) were evaluated. Detection of Ki-67 and COX-2 protein expression was conducted by immunohistochemistry. Data were statistically analyzed using Mann-Whitney U test and Spearman's rank correlation coefficient. No significant differences were found in the expression of Ki-67 and COX-2 between dentigerous cysts and ameloblastomas (P>0.05). A significant positive correlation (P=0.018) and highly significant positive correlation (P=0.004) were found between Ki-67 and COX-2 expression in the odontogenic epithelium of dentigerous cyst and ameloblastoma, respectively. COX-2 was expressed in the odontogenic epithelium of dentigerous cyst and ameloblastoma. It may contribute to local extension of these lesions by increasing the proliferation of their odontogenic epithelial cells.

Orthokeratinized odontogenic cyst masquerading as dentigerous cyst

The orthokeratinized odontogenic cyst (OOC) is a rare developmental odontogenic cyst that has been considered as a variant of the keratocystic odontogenic tumor until Wright (1981) defined it as a different entity. Recognition of OOC as a unique entity has long been due, yet its inexplicable clinical, radiographic presentation resembling dentigerous cyst due to its association to an impacted tooth, and its histological features makes it rather perplexing. This is the report of a case of OOC in relation to an impacted maxillary canine and its immunohistochemical analysis with Ki-67.

Ameloblastoma vs basal cell carcinoma: an immunohistochemical comparison

Despite behavioral mimicry of ameloblastoma (AB) and basal cell carcinoma (BCC), they are classified at 2 extremes within pertinent WHO classifications with respect to benign and malignant designation. This study aims to appraise the current allocation of AB in the classification through an immunohistochemical comparison of some aspects of behavior with BCC. Sections from retrospectively retrieved formalin-fixed, paraffin-embedded tissue blocks of AB (n = 37) and BCC (n = 34) were comparatively examined for the immunohistochemical expression for Ki-67, Bcl-2, MMP-2, MMP-9, CD31, and D2-40 monoclonal antibodies. No statistically significant differences between the tumors were found regarding the immunoexpressions of Bcl-2 (P = .252), CD31 microvessel density (P = .895), lymphatic vessel density (P = .642), and MMP-9 stromal expression (P = .083). MMP-2 expression was significantly higher in epithelial and stromal regions of AB (P = .009 and P = .001, respectively), whereas Ki-67 and MMP-9 epithelial expressions were significantly higher in BCC (P < .000 and P = .026, respectively). Within the studied immunohistochemical attributes for tumor behavior, the study accentuated the overall behavioral mimicry of the tumors and indicated that BCCs surmount ABs by the proliferative rate only.

TGF-β in jaw tumor fluids induces RANKL expression in stromal fibroblasts

Odontogenic tumors and cysts, arising in the jawbones, grow by resorption and destruction of the jawbones. However, mechanisms underlying bone resorption by odontogenic tumors/cysts remain unclear. Odontogenic tumors/cysts comprise odontogenic epithelial cells and stromal fibroblasts, which originate from the developing tooth germ. It has been demonstrated that odontogenic epithelial cells of the developing tooth germ induce osteoclastogenesis to prevent the tooth germ from invading the developing bone to maintain its structure in developing bones. Thus, we hypothesized that odontogenic epithelial cells of odontogenic tumors/cysts induce osteoclast formation, which plays potential roles in tumor/cyst outgrowth into the jawbone. The purpose of this study was to examine osteoclastogenesis by cytokines, focusing on transforming growth factor-β (TGF-β), produced by odontogenic epithelial cells. We observed two pathways for receptor activator of NF-κB ligand (RANKL) induction by keratocystic odontogenic tumor fluid: the cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) pathway through interleukin-1α (IL-1α) signaling and non-COX-2/PGE2 pathway through TGF-β receptor signaling. TGF-β1 and IL-1α produced by odontogenic tumors/cysts induced osteoclastogenesis directly in the osteoclast precursor cells and indirectly via increased RANKL induction in the stroma.

Immunohistochemical evaluation of myofibroblast density in odontogenic cysts and tumors

Background. The aim of this study was to investigate myofibroblast (MF) density in a broad spectrum of odontogenic cysts and tumors and the relation between the density of MFs and the clinical behavior of these lesions.

Methods. A total of 105 cases of odontogenic lesions, including unicystic ameloblastoma (UAM), solid ameloblastoma (SA), odontogenic keratocyst (OKC), dentigerous cyst (DC), radicular cyst (RC) (15 for each category), and odontogenic myxoma (OM), adenomatoid odontogenic tumor (AOT), calcifying odontogenic cyst (COC) (10 for each category), were immunohistochemically stained with anti-α-smooth muscle actin antibody. The mean percentage of positive cells in 10 high-power fields was considered as MF density for each case.

Results. A statistically significant difference was observed in the mean scores between the study groups (P < 0.001). The intensity of MFs was significantly higher in odontogenic tumors compared to odontogenic cysts (P < 0.001). There was no statistically significant difference between odontogenic tumors, except between UAM and OM (P = 0.041). The difference between OKC and odontogenic tumors was not statistically significant (P > 0.05). The number of MFs was significantly higher in OKC and lower in COC compared to other odontogenic cysts (P = 0.007 and P = 0.045, respectively).

Conclusion. The results of the present study suggest a role for MFs in the aggressive behavior of odontogenic lesions. MFs may represent an important target of therapy, especially for aggressive odontogenic lesions. Our findings support the classification of OKC in the category of odontogenic tumors.

Comparision of Immunohistochemical Expression of CD10 in Odontogenic Cysts

BACKGROUND

Expression of CD10 has been documented in various tumors like nasopharyngeal carcinoma, gastric carcinoma, squamous cell carcinoma, odontogenic tumors.

AIM

To evaluate and compare CD10 expression in odontogenic cysts like radicular cyst, dentigerous cyst and odontogenic keratocyst (OKC).

MATERIALS AND METHODS

Total 60 cases were included in the study, comprising 20 cases each of radicular, dentigerous and odontogenic keratocyst. Each case was evaluated and compared for immunohistochemical expression of CD10. RESULTS obtained were statistically analysed using ANOVA test followed by post hoc test Tukey-Kramer Multiple Comparisons Test for continuous variable and Chi-square test for discrete variable.

RESULTS

More number of cases showing sub-epithelial stromal CD10 expression were found in OKC among the cysts.

CONCLUSION

CD10 expression was more in OKC compared to radicular and dentigerous cysts.

Evaluation and comparison of expression of p63 in odontogenic keratocyst, solid ameloblastoma and unicystic ameloblastoma

Background and Objectives:

The behavior of odontogenic lesions varies with some tumors behaving like a cyst and some cysts behaving like tumors. p63, a member of the p53 family of tumor suppressor genes has recently come into light in view of its role as an oncogene. The aim of the present study was to investigate the expression of p63 protein in OKC, Solid ameloblastoma, Unicystic Ameloblastoma and Follicular tissue.

Materials and Methods:

p63 expression was compared in 12 cases of OKC, 12 Solid Ameloblastoma, 14 cases of Unicystic ameloblastoma and 10 cases of Follicular tissue using immunohistochemical technique. All 48 cases were subjected to heat-induced antigen retrieval method using citrate buffer in a pressure cooker. Then the sections were stained with anti-p63 polyclonal antibody and visualized using super sensitive polymer HRP detection system. In each case, number of cells showing p63 positivity were assessed in two compartments - basal and suprabasal and compared.

Results:

Statistical analysis showed that p63 expression in the suprabasal compartment in Odontogenic keratocysts was equivalent to that of central neoplastic cells of Solid Ameloblastoma and Unicystic Ameloblastoma type 3. Statistically significant difference in the expression of p63 was observed between OKC and Unicystic Ameloblastoma Type 1 and Solid Ameloblastoma and Unicystic Ameloblastoma Type 1.

Conclusion:

We conclude that the higher expression of p63 in these odontogenic lesions correlates well with their aggressive behavior and thereby suggesting alterations in treatment modalities.

Orthokeratinized odontogenic cyst of the mandible: A rare case report with a systematic review

Orthokeratinized odontogenic cyst (OOC) is an odontogenic cyst was initially termed as the uncommon orthokeratinized type of odontogenic keratocyst by the World Health Organization. It usually occurs in mandible. Various studies have shown that OOC has typical characteristic clinicopathologic features when compared to other developmental odontogenic lesions such as dentigerous cyst and the keratocystic odontogenic tumor (KCOT). Rare recurrence was noted after surgical removal of the lesion. The purpose of this article is to present a case of OOC arising in the posterior mandible and emphasize on differentiating it from the KCOT and dentigerous cyst.

Multiple orthokeratinized odontogenic cysts: a case report

The purpose of this report is to document the clinical, radiographic, pathological and molecular findings of the first case of multiple orthokeratinized odontogenic cysts (OOCs). Multiple odontogenic keratocysts are one of the major features of nevoid basal cell carcinoma syndrome (NBCCS), and loss of heterozygosity in the PTCH gene, the culprit gene for NBCCS, has recently been found in sporadic OOC cases. Therefore, in this presenting case, we also investigated the possibility that this patient might also have NBCCS, by comparing the available clinical information and the molecular findings of this case to the diagnostic criteria for NBCCS (as proposed by the First International Colloquium on NBCCS in 2011). However, this patient with multiple OOCs showed no evidence of having NBCCS. This conclusion supports the findings from previous case series based on sporadic cases that OOC does not appear to be associated with NBCCS.

Peripheral ameloblastoma of the upper gingiva: Report of a case and literature review

According to the 2005 histological classification of odontogenic neoplasms by the World Health Organization, ameloblastoma is a benign, locally invasive epithelial odontogenic tumor of putative enamel organ origin. There are four distinct subgroups in which this neoplasm can be gathered: the solid/multicystic type, the unicystic type, the desmoplastic and the peripheral type. Peripheral ameloblastoma is believed to be the rarest subgroup, making up for 2 to 10% of all ameloblastomas. From its first description by Kuru in 1911 to date, less than 200 cases of PA have been described in literature. PAs commonly affect the mandible, in the maxilla the most common location is the soft palatal tissue of the tuberosity area. The present report discusses a rare case of PA aroused in the gingiva of upper jaw in a 64-year-old woman. The treatment of the lesion and its immunohistochemical phenotype are described. A review of the literature is also performed, focusing on the epidemiological and pathological aspects of the lesions and their implications on the therapy.

Key words:Peripheral ameloblastoma, upper gingiva, ameloblastoma.

Orthokeratinizing odontogenic cyst of maxilla with complex odontoma

The orthokeratinized odontogenic cyst (OOC) and odontoma are the odontogenic cyst and tumor respectively that are minimally invasive neoplasms of head and neck region. OOC is a rare variant of odontogenic cyst characterized by the presence of excessive orthokeratin covering the cystic lining. Odontoma is a benign neoplasm/hamartoma often discovered accidently on panoramic radiographs. We came across a case of a 26-year-old male with swelling on his face along with difficulty in breathing. On the basis of radiographic and histopathological findings the final diagnosis of OOC associated with odontoma was given. However, there is no report in the English literature of the simultaneous occurrence of these two lesions and hence this case is very rare. It is unclear whether the two lesions were just coincidental or were actually related to each other.

Evaluation of stromal myofibroblasts expression in keratocystic odontogenic tumor and orthokeratinized odontogenic cysts: A comparative study

Objective:

Keratocystic odontogenic tumor (KCOT) has an aggressive clinical course and a high tendency of recurrence, while orthokeratinized odontogenic cyst (OOC) has different characteristics and does not show aggressive behaviour. Even the treatment of these two lesions varies considerably. A large number of epithelial molecules have been studied in order to differentiate odontogenic keratocyst (OKC) from OOC, but stromal factors have not been adequately studied. Recently, tumor stroma has evolved as a particular field of interest. In the present study, we aim to evaluate and compare the expression of stromal myofibroblasts (MFs) in these entities and correlate it to its aggressive behavior. The term ‘keratocystic odontogenic tumor’ has been introduced by WHO in 2005 for odontogenic keratocyst keeping in mind its aggressive behavior, however still many pathologists and clinicians use the term OKC synonymously.

Materials and Methods:

A total of 10 cases of KCOT and 10 cases of OOC were stained for alpha-smooth muscle actin (αSMA) for demonstration of stromal MFs. MF frequency was assessed as the number of αSMA-positive stromal cells in 10 high power fields, presented as the mean number of positive cells per field.

Results:

Counts showed that the mean number of positive cells in KCOT (20.6 ± 2.05) was significantly higher than that seen in OOC (10.4 ± 1.06) (P < 0.05).

Conclusion:

The different behaviors of these lesions are compatible with the finding of the present study. The increased number of stromal MFs in KCOT in comparison to OOC correlates with its aggressive behavior and increased tendency towards recurrence.

Expression of cell cycle and apoptosis-related proteins in ameloblastoma and keratocystic odontogenic tumor

Tumors arising from epithelium of the odontogenic apparatus or from its derivatives or remnants exhibit considerable histologic variation and are classified into several benign and malignant entities. A high proliferative activity of the odontogenic epithelium in ameloblastoma (AM) and keratocystic odontogenic tumor (KCOT) has been demonstrated in some studies individually. However, very few previous studies have simultaneously evaluated cell proliferation and apoptotic indexes in AM and KCOT, comparing both lesions. The aim of this study was to assess and compare cell proliferation and apoptotic rates between these two tumors. Specimens of 15 solid AM and 15 KCOT were evaluated. The proliferation index (PI) was assessed by immunohistochemical detection of Ki-67 and the apoptotic index (AI) by methyl green-pyronin stain. KCOT presented a higher PI than AM (P < .05). No statistically significant difference was found in the AI between AM and KCOT. PI and AI were higher in the peripheral cells of AM and respectively in the suprabasal and superficial layers of KCOT. In conclusion, KCOT showed a higher cell proliferation than AM and the AI was similar between these tumors. These findings reinforce the classification of KCOT as an odontogenic tumor and should contribute to its aggressive clinical behavior.

Orthokeratinized odontogenic cyst: a report of three clinical cases

The orthokeratinized odontogenic cyst (OOC) is a rare developmental odontogenic cyst that has been considered as a variant of the keratocystic odontogenic tumour (KCOT) until Wright (1981) defined it as a different entity. Surgery is the usual treatment, and recurrence or association with Gorlin-Goltz syndrome has rarely been described. In this report, we presented three cases of this pathology, and we review the principal clinical, histological, radiological, and therapeutic aspects. Case 1. A 73-year-old female presents with a slight swelling on the right mandible, associated with an unilocular well-defined radiolucent lesion. Case 2. A 27-year-old female presents with a painful mandibular swelling associated with an unilocular radiolucent lesion posterior to the 4.8. Case 3. A 61-year-old male was casually detected presents with an unilocular radiolucent lesion distal to the 4.8. Conclusion. The OOC is a specific odontogenic clinicopathological entity that should be differentiated from the KCOT as it presents a completely different biological behaviour.

c-Myc oncogene expression in selected odontogenic cysts and tumors: An immunohistochemical study

Aim:

To investigate the role of c-Myc oncogene in selected odontogenic cysts and tumors.

Materials and Methods:

Ten cases each of ameloblastoma, adenomatoid odontogenic tumor (AOT), odontogenic keratocyst (OKC), dentigerous cyst, and radicular cyst were selected and primary monoclonal mouse anti-human c-Myc antibody was used in a dilution of 1: 50. Statistical Analysis was performed using Mann Whitney U test.

Results:

80% positivity was observed in ameloblastoma, AOT and OKC; 50% positivity in radicular cyst and 20% positivity in dentigerous cyst. Comparison of c-Myc expression between ameloblastoma and AOT did not reveal significant results. Similarly, no statistical significance was observed when results of OKC were compared with ameloblastoma and AOT. In contrast, significant differences were seen on comparison of dentigerous cyst with ameloblastoma and AOT and radicular cyst with AOT.

Conclusion:

From the above data we conclude that (1) Ameloblastoma and AOT have similar proliferative potential and their biologic behavior cannot possibly be attributed to it. (2) OKC has an intrinsic growth potential which is absent in other cysts and reinforces its classification as keratocystic odontogenic tumor.

Contrast-enhanced multidetector computerized tomography for odontogenic cysts and cystic-appearing tumors of the jaws: is it useful?

OBJECTIVE

The purpose of this study was to investigate the usefulness of computerized tomography (CT), particularly contrast-enhanced CT, in differentiation of jaw cysts and cystic-appearing tumors.

STUDY DESIGN

We retrospectively analyzed contrast-enhanced CT images of 90 patients with odontogenic jaw cysts or cystic-appearing tumors. The lesion size and CT values were measured and the short axis to long axis (S/L) ratio, contrast enhancement (CE) ratio, and standard deviation ratio were calculated.

RESULTS

The lesion size and the S/L ratio of keratocystic odontogenic tumors were significantly different from those of radicular cysts and follicular cysts. There were no significant differences in the CE ratio among the lesions.

CONCLUSIONS

Multidetector CT provided diagnostic information about the size of odontogenic cysts and cystic-appearing tumors of the jaws that was related to the lesion type, but showed no relation between CE ratio and the type of these lesions.

Keratocystic odontogenic tumor: a retrospective analysis of genetic, immunohistochemical and therapeutic features. Proposal of a multicenter clinical survey tool

OBJECTIVE

In 2005, the World Health Organization reclassified the parakeratinizing odontogenic keratocyst as a neoplasm. This article reviews the research leading to this reclassification, and validates a new survey tool that can be easily used to pool surgical and recurrence data from multiple offices.

STUDY DESIGN

All odontogenic lesions accessioned in the Iowa Surgical Oral Pathology Laboratory between 1949 and 2010 were identified from the database. A survey tool to assess treatment and follow-up was created. A total of 46 surgeons agreed to participate.

RESULTS

A total of 70 keratocystic odontogenic tumors (KOTs) had documented recurrences at follow-up intervals ranging from 6 months to 5 years. Primary tumors that recurred ranged in size as measured by greatest radiographic diameter from 0.7 to 6 cm.

CONCLUSIONS

This survey tool is recommended as standard allowing treatment of cases by multiple practitioners to be compared retrospectively or prospectively.

Co-expression of Ki-67 and p53 protein in ameloblastoma and keratocystic odontogenic tumor

OBJECTIVES

The purpose of this study was to evaluate the cell proliferation and p53 protein expression in ameloblastomas (ABs), keratocystic odontogenic tumor (KCOT) and dentigerous cyst (DC).

METHOD

The immunohistochemistry were carried out for Ki-67 and p53 protein expression by using MIB-1 clone and DO-7 clone, respectively, in ABs (n = 23), KCOT (n = 32), DC (n = 30), normal oral mucosa (NOM) (n = 12) and fetal oral mucosa (FOM) (n = 10).

RESULTS

Both the Ki-67 LI Labeling index (LI) and p53 LI was significantly higher in ABs than KCOT, DC, NOM and FOM. The Ki-67 LI and p53 LI was significantly higher in KCOT as compared to DC. Ki-67 LI and p53 LI was observed in descending order in ABs, KOCT, FOM, NOM and DC. There was significant correlation between Ki-67 expression and p53 expression in ABs, KCOT, DC and NOM. The densely stained p53 positive cells were noted higher in ABs than KCOT. The very few densely p53 positive cells were noted in DC, NOM and FOM.

CONCLUSION

The results suggest that the p53 protein expression does not necessarily imply an association with malignant disease and/or p53 gene mutation, but a tendency to be expressed in an increasing quantitative and qualitative manner, as the biologic behavior of odontogenic cyst or tumors becomes more aggressive. p53 over-expression may promote cell proliferation in odontogenic lesions. Thus, it can be stipulated that Ki-67 and p53 protein expression can be used as a prognostic marker in odontogenic lesions.

Cell proliferation and apoptosis in ameloblastomas and keratocystic odontogenic tumors

A high proliferative activity of the odontogenic epithelium in ameloblastoma (AM) and keratocystic odontogenic tumor (KOT) has been demonstrated. However, no previous study has simultaneously evaluated cell proliferation and apoptotic indexes in AM and KOT, comparing both lesions. The aim of this study was to assess and compare cell proliferation and apoptotic rates between these two tumors. Specimens of 11 solid AM and 11 sporadic KOT were evaluated. The proliferation index (PI) was assessed by immunohistochemical detection of Ki-67 and the apoptotic index (AI) by methyl green-pyronine and in situ DNA nick end-labelling methods. KOT presented a higher PI than AM (p<0.05). No statistically significant difference was found in the AI between AM and KOT. PI and AI were higher in the peripheral cells of AM and respectively in the suprabasal and superficial layers of KOT. In conclusion, KOT showed a higher cell proliferation than AM and the AI was similar between these tumors. These findings reinforce the classification of KOT as an odontogenic tumor and should contribute to its aggressive clinical behavior.

Ki-67 and MCM-2 in dental follicle and odontogenic cysts: the effects of inflammation on proliferative markers

The aim of this study was to investigate whether there is any association between inflammation and the expression of markers of cell cycle entry (Ki-67 and MCM-2) in dental follicle (DF) of asymptomatic impacted teeth and odontogenic cysts. The study consisted of 70 DFs and 20 odontogenic cysts (radicular cyst (RC), dentigerous cyst (DC) and keratocytic odontogenic tumor (KCOT) located at posterior mandibular region. Histological findings of inflammation for all specimen and mucous cell prosoplasia, squamous metaplasia, glandular epithelium for all DFs were stained with hematoxyline and eosin, periodic acid schiff, alcian blue, and mucin. Epithelial cell proliferation was determined by using immunohistochemical labeling for Ki-67 and MCM-2. The histologic examinations showed 16% mucous cell prosoplasia, 54% squamous metaplasia, 20% glandular epithelium, 37% inflammation. Inflammation was detected in all RCs and %62 in DF, %43 in DC and KCOT. Positive correlation was found between the inflammation of DF and odontogenic cysts (P < 0.01). The mean Ki-67 and MCM-2 expressions were found 9, 64 ± 5, 99 and 6, 34 ± 3, 81 in DF, 11, 85 ± 9, 01 and 13, 6 ± 9, 94 in odontogenic cysts, respectively. While the mean Ki-67 expressions were statistically significant in DF and KCOT (P < 0.01), MCM-2 were significant in RC and KCOT (P < 0.01). MCM-2 expresion in RCs were statistically significant than KCOT (P < 0.01). The results of this study indicated that the higher MCM-2 expressions in RC than the KCOT might be related to the inflammation and this protein might be more sensitive to inflammation.

Odontogenic keratocysts/keratocystic odontogenic tumours: biological characteristics, clinical manifestation and treatment

BACKGROUND

Odontogenic keratocysts (OKCs) now reclassified as Keratocystic odontogenic tumours (KCOTs) are a clinical entity with a characteristic microscopic picture, kinetic growth and biological behaviour. They arise from the proliferation of the epithelial dental lamina in both maxilla and mandible and occur in patients of all ages. 70-80% of keratocysts are found in the mandible commonly in the angle between the jaw and mandibular branch and maxillary region of the third molar. The cysts are long latent, often symptomless and may attain remarkable dimensions without significant deformation of the jaw bones. They are often found during routine dental X-ray examination. Compared to other types of jaw cyst, odontogenic cysts have a striking tendency to rapid growth and re-occurrence.

AIMS

This review focuses on the biological characteristics, clinical behaviour and treatment of KCOTs.

METHODS

The databases searched were the PubMed interface of MEDLINE and LILACS.

RESULTS AND CONCLUSIONS

Ondontogenic keratinocysts are not currently a diagnostic problem. Orthopantomograms which are today ordinary tools of dental investigation enable diagnosis of clinically asymptomatic cystic lesions. The problem remains the optimal therapeutic approach to reduce the still high likelihood of postoperative recurrence. There is no complete consensus on the ideal operating procedure but cystectomy with delayed extirpation is favoured. An open question also remains the timeliness of screening for postoperative recurrences. Given that the first clinical manifestation of Nevoid Basal Cell Carcioma Syndome (NBCCS) may be lesions of this type, routine histopathological classification supplemented by analysis of immunophenotype should be done. Patients with proven sporadic and especially syndromic OKC should be long term screened. In patients with NBCC preventive X ray examination is recommended only once a year.

Histopathological Features of Keratocystic Odontogenic Tumor

The aim of this study was to describe the clinicopathologic features of 177 keratocystic odontogenic tumors (KCOTs) diagnosed in a Brazilian population. A total of 177 KCOTs were reviewed and affected 158 patients with ages ranging from 5 to 79 years (mean age = 32 years) with a slight female predominance. Mandible was the most common affected site (69.3%), and a unilocular radiolucency was the most common radiographic image. Microscopically, all cases showed at least focal areas of classic KCOT, but several histological aspects were also observed, including diffuse and focal epithelial lining hyperplasia (48.6%), epithelial budding (12.4%), reactive cytological alterations (11.3%), dystrophic calcification (7.9%), daughter cysts (7.8%), odontogenic epithelial remnants (4.5%), focal areas of orthokeratinization (2.8%), and ameloblastomatous epithelium (1.7%). These variations may make KCOT diagnosis challenging in some cases, so careful full-sample analysis and knowledge of these uncommon histological features associated with KCOT are essential for correct diagnosis.

A comparative immunohistochemical analysis of COX-2, p53, and Ki-67 expression in keratocystic odontogenic tumors

OBJECTIVE

The aim of the present study was to investigate the association between the expression of cyclooxygenase-2 (COX-2) in keratocystic odontogenic tumors (KCOT) and more commonly used markers, such as p53 and Ki-67.

STUDY DESIGN

Expression of cyclooxygenase-2 (COX-2) in 20 biopsy specimens of keratocystic odontogenic tumors (KCOT) has been analyzed and compared with the expression of previously reported markers Ki-67 and p53. Formalin-fixed, paraffin-embedded blocks were sectioned and used for hematoxylin-eosin (H&E) staining and incubated with anti-cox-2, anti-ki-67, and anti-p53 monoclonal antibodies for immunohistochemical examination. Detection of the COX-2 antibody was performed with the EnVision kit. Cellular staining pattern was cytoplasmatic for COX-2 and nuclear for both Ki-67 and p-53. Molecular expressions were semiquantitatively evaluated as negative (-), mild (±) or strong (+).

RESULTS

Mild to strong expression of COX-2 was observed in 20 (100%) of the cases. Fifteen (75%) of the KCOTs stained positive for p53 and 18 (90%) stained positive for Ki-67. There was no statistically relevant difference between the expressions of COX - 2, Ki-67, and p53.

CONCLUSIONS

Although COX-2 has rarely been used to assess the biological activity of the KCOT, the results portrayed in the current study and the current knowledge of the overall role known to be played by COX-2 in tumorigenesis suggest that COX-2 may be an important marker involved in the biological behavior of the KCOT. Larger studies are required to improve our knowledge of the possible role of COX-2 in the pathogenic mechanism involved in KCOT.

Evidence of loss of heterozygosity of the PTCH gene in orthokeratinized odontogenic cyst

The orthokeratinized odontogenic cyst (OOC) is an odontogenic cyst of unknown etiology. Clinical, histological, and biological differences are reported between keratocystic odontogenic tumor (KOT) and OOC. PTCH is a tumor suppressor gene related to sonic hedgehog (SHH) pathway important in embryological development. Considering that alterations in this pathway have been described in sporadic and nevoid basal cell syndrome-associated KOT, we tested the hypothesis that OOC is also associated with loss of heterozygosity (LOH) of the PTCH gene. Seven samples of OOC and seven of KOT were included in the study. D9S287, D9S196, and D9S127 microsatellite markers located in the region of PTCH gene, at chromosome 9q, were investigated for LOH. There was loss in at least one locus in 5/7 KOT and in 4/7 OOC samples. The present finding demonstrates that, despite the existence of clinical, morphological, immunohistochemical, and biological behavior differences between OOC and KOT, both harbor similar genetic alterations at 9q.

Odontogenic epithelium: immunolabeling of Ki-67, EGFR and survivin in pericoronal follicles, dentigerous cysts and keratocystic odontogenic tumors

The aim of this study was to evaluate the biological profile of odontogenic epithelium by immunolabeling of epidermal growth factor receptor (EGFR), Ki-67 and survivin in keratocystic odontogenic tumors (KOT), dentigerous cysts (DC), and pericoronal follicles (PF). Immunohistochemical analysis was performed in 13 KOTs, 14 DCs and 9 PFs. Immunolabeling was analyzed in the basal and suprabasal layers of KOTs and DCs, and in the islands of odontogenic epithelium and/or reduced enamel epithelium of PFs. KOTs showed the highest proliferation rate among the three groups, mainly in suprabasal layers. EGFR immunolabeling was observed mainly in the cytoplasm in basal and suprabasal layers of KOTs and in the suprabasal layer of DCs. Immunolabeling in both membrane and cytoplasm was greater in PFs. In PFs, membrane-only staining was observed. Survivin immunolabeling showed a greater percentage of positive cells (scoring +++) in the suprabasal layer of KOTs. In DCs, both layers showed similar percentages of cells scoring +++; PFs showed the highest percentage of these cells. In KOTs, epithelial cells showed stimulus-independent neoplastic proliferative characteristics, suggesting the presence of a suprabasal proliferative compartment, maintained by inhibition of apoptosis. In DCs, the basal layer seemed to proliferate in response to stimulus. Although PFs showed low proliferative activity, the expression of EGFR indicates that some cells have a high capacity to respond to stimuli, which could probably explain the origin of odontogenic lesions.

Immunohistochemical expression of vascular endothelial growth factor (VEGF) in different types of odontogenic cysts

The objective of the present study was to evaluate vascular endothelial growth factor (VEGF) expression in different types of odontogenic cysts. A total of 25 parakeratotic odontogenic keratocysts (POKCs), 16 orthokeratotic odontogenic keratocysts (OOKCs), and 28 follicular cysts (FCs) were evaluated semiquantitatively for immunohistochemical analysis of VEGF in epithelial cells, endothelial cells of blood vessels, inflammatory cells and focally stromal cells. A significant different expression of VEGF in all cell components was found in keratocysts compared to FCs. The POKCs (80%) and OOKCs (68%) showed more than 50% VEGF positive epithelial cells, whereas the majority of FCs (71%) were either negative in the epithelium or showed less than 10% positive cells. Similarly, the POKCs (88%) and OOKCs (68%) showed more than 50% positive endothelial cells, whereas the FCs (75%) were either negative or showed less than 10% VEGF positive endothelial cells. The highest percentage of cases with score 2 positivity in the stromal cells was observed in POKCs (68%); OOKCs showed a score 2 positivity in 44%, score 1 in 31% and score 0 in 25%, whereas 68% of FCs showed a score 0, 25% a score 1 and only 7% of cases showed a score 2. No statistically significant differences were observed between POKCs and OOKCs in VEGF expression in the epithelial and endothelial cells, whereas the positivity score in stromal cells was significantly higher in POKCs compared to OOKCs. The present results can support the hypothesis that angiogenesis is an active mechanism in the invasive growth of the OKC.

Keratocystic odontogenic tumor associated with nevoid basal cell carcinoma syndrome: similar behavior to sporadic type?

OBJECTIVE

The objective of this study was to analyze the expression of proliferative markers and p53 in keratocystic odontogenic tumor (KCOT) sporadic type and KCOT associated with nevoid basal cell carcinoma syndrome (NBCCS).

STUDY DESIGN AND SETTING

We performed a cross-sectional study. A total of 19 patients with KCOT were selected from the Oral Pathology Laboratory archives, Central University of Venezuela, from 1995 to 2005.

SUBJECTS AND METHODS

Twelve cases corresponded to sporadic KCOT, and seven cases were associated with NBCCS. Immunohistochemical analysis for p53, proliferating cell nuclear antigen (PCNA), and Ki-67 was performed in all 19 cases.

RESULTS

Of the seven cases associated with NBCCS, six (86%) were positive for PCNA. From the 12 sporadic cases, nine (75%) were positive for PCNA. Only one case of sporadic KCOT showed Ki-67 positivity. Five of 12 (42%) cases of sporadic KCOT were positive for p53, and only one (14%) case associated with NBCCS was positive for p53.

CONCLUSION

On the basis of the analysis of the expression of PCNA, Ki-67, and p53, there appears to be no evidence to indicate higher aggressiveness in growth and infiltrative behavior in syndromic KCOT compared with the sporadic type. Therefore, surgical treatment may be approached in the same manner in KCOT sporadic and syndromic with the goal of minimizing recurrence.