Statment of the Problem: Podoplanin can indicate the lymphangiogenesis. On the other hand, lymphangiogenesis affects the biological behavior of lesions. The clinical behavior of odontogenic keratocysts (OKC) and Dentigerous cysts (DC) is different.Purpose: This study aimed to evaluate the immunohistochemical expression of podoplanin and to investigate lymphangiogenesis in OKCs as compared to DCs.Materials and Method: In this experimental laboratory study, sixty paraffined blocks, including 30 OKC and 30 DC samples, were examined in this study, all of which were histopathologically non-inflamed. To evaluate lymphangiogenesis, the immunohistochemi­cal reaction of D2-40 was evaluated via cytoplasmic and membrane staining of lymphatic endothelial cells. The expression of podoplanin in the epithelial cells of two cyst groups was also examined. To analyze the collected data and compare the results between the two groups of cysts, independent samples t-test, Mann-Whitney U test, and Chi-square test were performed in SPSS version 22. The significance level was set at 0.05.Results: The mean lymph node count and podoplanin expression were significantly higher in the OKC epithelium as compared to DC (P<0.001). Based on the results, 90% of OKC samples and 43.3% of DC samples showed grade 3 staining.Conclusion: The rate of lymphangiogenesis and podoplanin expression in the epithelium were higher in OKCs compared to DCs. According to the results, the expression of podopla-nin may be a useful marker for determining the invasiveness and proliferation of OKC.

In this paper, an unusual case of pigmented Dentigerous cyst in a 37-year-old Iranian man with multiple Dentigerous cysts of maxilla and mandible is reported. In addition to the characteristic histopathologic features of Dentigerous cyst, numerous melanin granules which were distributed throughout the epithelial lining of one of these cysts were also noted. The histochemical study using Fontana's staining indicated that the pigment was melanin and many of the cells containing melanin were immunohistochemically positive for S-100 protein. Although no firm conclusion could be drawn from the present case regarding melanin origin in Dentigerous cyst, the possible histogenesis of melanocytes in odontogenic lesions is discussed.  

Background and Aim: Odontogenic keratocyst (OKC) and Dentigerous cyst (DC) are two common developmental cysts involving the jaws. The role of matrix metalloproteinases 2 (MMP2) and 19 (MMP19) in progression and invasion of some cysts and tumors has been documented. This study sought to assess the expression of MMP2 and MMP19 in OKCs and DCs. Materials and Methods: In this descriptive analytical study, 58 paraffin blocks including 20 DCs, 20 OKCs and 18 dental follicles (DF) were chosen from the archives of the Oral and Maxillofacial Pathology Department, Shahid Beheshti University of Medical Sciences. Immunohistochemistry (IHC) staining was performed to detect the expression of MMP2 and MMP19 using the EnVision technique. Data were analyzed using the Chi square, Fisher’ s exact, Kruskal Wallis, Mann Whitney and Spearman’ s correlation tests. Results: Both markers were expressed in OKCs and DCs. Expression of MMP19 was higher in OKCs compared to DCs and DFs. Significant differences existed among the groups in the intensity of staining of the epithelium (P<0. 05) and the connective tissue (P<0. 001) for MMP19. Expression of MMP2 in DCs was higher than in OKCs and DFs. Significant differences existed among the groups in the intensity and percentage of staining of the epithelium (P<0. 001) and the connective tissue (P<0. 05) for MMP2. Conclusion: Our findings indicated the potential role of MMP19 in the invasive behavior of OKC. Greater expression of MMP2 in DCs may indicate its role in multi-dimensional growth of this cyst. Nevertheless, further studies are required to make an evidence-based decision.

Introduction: Dentigerous cyst (DC) is the most common pathologic pericoronal radiolucency and the odontogenic keratocyst (OKC) radiographic features appear as unilocular, multilocular or pericoronal radiolucency. Since OKC is very invasive and has a high recurrence rate and its radiographic features are like Dentigerous cyst and bone important lesions such as amelobastoma and mural ameloblastoma, it seems necessary to recognize radiographic features of these two cysts.The aim of this study was to compare panoramic radiographic findings in DC and OKC. Materials & Methods: In this descriptive (case series) study, 41 panoramic radiographs of 26 patients with DC and 15 patients with OKC, were evaluated by one maxillofacial radiologist as an observer.The radiographic information included persent pericoronal radiolucency , unilocular or multilocular radiolucency, smooth or scalloped periphery, impacted tooth, size and area of cyst, age and sex. Finally, the data were analyzed using Chi-square and T tests statistically. Results: one case of DC had multiolocular radiolucency, 4 cases of OKC had unilocular pericoronal, 2 cases had multilocular pericoronal, 2 cases had unilocular non-pericoronal radiolucency and 7 cases had non-pericoronal multilocular radiolucency. A significant relationship was detected among the mean age of patients, and mean area of cysts (P<0.05).Conclusion: Based on the present study, DC was more common in maxillary canine appearing mainly as a pericoronal unilocular pattern, while OKC was more common in mandible appearing mainly as a multilocular pattern.

Introduction: Dentigerous cyst (the most common developmental cyst), periapical cyst (the most common jaw cyst) and residual cyst may transfer to neoplasm. In this study, the expression of P53 & MDM2 (cell proliferative regulators) and their relation to proliferation and transformation of these cysts were evaluated. Materials & Methods: In this cross-sectional study, expressions of P53 and MDM2 markers in 60 samples of paraffin blocks (20 samples for each cyst) were examined by Immunohistochemistry method and the percentage, intensity, and location of involved epithelial cells were evaluated. Statistical tests included one way ANOVA and Tukey test for evaluation of expression, and Kruskal-Wallis for intensity comparison and Kendall for detecting correlation between markers.Results: Periapical cyst showed complete expression of markers. Severity, percentage and depth of MDM2 expression were higher than P53. Marker expression for residual cyst was highly intensive and also in full thickness of epithelium, but it was basillary with lower intensity in Dentigerous cyst. Expression of P53 and MDM2 had significant differences in these three cysts (P=0.01, 0.03 respectively), and also significant difference for percentage and severity of MDM2 between the three groups (P=0.003, 0.001 respectively). There was a positive linear correlation between P53 and MDM2 expression (P<0.001).Conclusion: In residual cyst, there was a correlation between increase in MDM2and P53 expression, but not in periapical cyst. Dentigerous cyst failed to strongly express each of the markers. Nevertheless, it could be said that increase in expression of these markers could be related to pathogenesis and neoplastic transformation of these cysts.

Background & Aim: Epithelial odontogenic cysts and tumors originate from the odontogenic epithelium and superficial epithelial lining of the oral mucosa. Differences in the proliferation of epithelial cell islands play an important role in the pathogenesis of these lesions. The aim of this study was to compare the frequency of odontogenic epithelium in the connective tissue of Dentigerous cysts and odontogenic keratocysts from registered samples of oral pathology archive, dental dental faculty Isfahan University of Medical Sciences. Material and Methods: In this cross-sectional descriptive study, 30 odontogenic keratocysts and 30 Dentigerous cysts prepared by excisional biopsy were selected and clinical information including age, sex and location was obtained from the archives of patients referred to the Oral and Maxillofacial Pathology Department of Isfahan Dental School. Histopathological slides were examined by two pathologists to confirm the diagnosis and evaluation of odontogenic epithelial islands and cords in the connective tissue of the lesions. The data were entered into SPSS23 software and statistically analyzed by Fisher's exact test, Mann-Whitney, Kruskal-Wallis and T-test. Results: The number of specimens with large and small epithelial islands and epithelial cords was significantly higher in odontogenic keratocysts than Dentigerous cysts (p-value = 0. 014). There was no significant difference between the mean number of large and small epithelial islands and cords in connective tissue based on gender and location in each group (p-value >0. 05). There was a significant inverse relationship between the mean number of large and small islands of odontogenic epithelium and epithelial cords in the connective tissue of the two lesions with the mean age of patients (p-value = 0. 035). Conclusion: It seems that the samples with large and small epithelial islands and epithelial cords were significantly higher in OKCs than Dentigerous cysts and this difference may play a role in the different biological behavior and recurrence of these two lesions.

Introduction: Dentigerous cysts (DCs) are the most common developmental cysts of the jaws, mostly associated with impacted third molars and canines. Multiple or bilateral DCs are rare and typically occur in association with some syndromes including cleidocranial dysplasia and Gorlin-Goltz. The occurrence of multiple DCs is rare in the absence of these syndromes. Case Presentation: A 28-year-old male was referred for pain and mobility of the left mandibular second molar. On radiological examination, follicular enlargement in relation to the unerupted third molar was found. Another unilocular radiolucent area was seen in relation to the right-side unerupted third molar. A provisional diagnosis of multiple odontogenic keratocysts was made; however, the histopathological studies revealed DC on both sides. The patient’ s medical history was non-significant, and no associated syndromes were present. Bilateral DCs are rare in the absence of a syndrome, and to date, only 53 cases have been reported in the literature. Here, we report the unusual bilateral occurrence of DCs associated with unerupted mandibular third molars in a non-syndromic patient with a review of the literature for this unusual finding. The one-year follow-up radiograph of the patient showed a favorable osseous formation with no evidence of recurrence of the cysts. Conclusion: A comprehensive radiographic examination, especially for mandibular third molars, is essential for correct diagnosis and management of the lesions. Furthermore, systematic clinical examinations should be performed to rule out any associated syndrome.