Ki-67 expression in dentigerous cysts, unicystic ameloblastomas, and ameloblastomas arising from dental cysts

This study investigated whether or not an ameloblastoma developing in the wall of a dentigerous cyst is a distinct lesion from the unicystic ameloblastoma. An immunohistochemical evaluation of Ki-67 in dentigerous cysts, unicystic ameloblastomas, and ameloblastomas arising in dentigerous cysts was done. The values of Ki-67 positivity were 3.14 for the dentigerous cyst, between 5.32 and 16.56 for unicystic ameloblastoma, and 11.77 for ameloblastoma arising in a dentigerous cyst. Statistically significant differences were found between the dentigerous cyst and the unicystic ameloblastoma and between the dentigerous cyst and the ameloblastoma arising from a dentigerous cyst. No statistically significant difference was present between unicystic ameloblastoma and ameloblastoma arising from dentigerous cyst. These immunohistochemical data confirm the hypothesis that an ameloblastoma arising from a dentigerous cyst has a similar biological behavior to the unicystic ameloblastoma and should be considered as merely a histologic variant.     

Inability to distinguish ameloblastomas from odontogenic cysts based on expression of blood cell carbohydrates

This study was designed to confirm the report by Vedtofte and coworkers that the epithelium of ameloblastomas can be distinguished from that of nonneoplastic odontogenic cysts by differences in expressivity of cell surface carbohydrates with blood group specificity. Immunoperoxidase techniques were used to study four radicular cysts, seven dentigerous cysts, six ameloblastomas, and six examples of plexiform unicystic ameloblastoma. No consistent differences were found in the expressivity of the blood group carbohydrates A, B, and H type 2 in the nonneoplastic odontogenic cysts as compared to the ameloblastomas. Consequently, the demonstration of these blood group carbohydrates is of no value in the differential diagnosis of nonneoplastic odontogenic epithelium from ameloblastomas, including especially the plexiform unicystic ameloblastoma, the pattern that so closely resembles hyperplastic odontogenic epithelium.     

牙源性囊肿和成釉细胞瘤体外骨吸收的实验研究

目的定量分析牙源性角化囊肿和成釉细胞瘤的体外骨吸收效应,探讨其颌骨吸收机制。方法收集25例牙源性囊肿[牙源性角化囊肿(OKC)14例、牙源性角化囊肿伴感染6例、含牙囊肿(DC)5例]和7例成釉细胞瘤的新鲜组织块行体外培养(24h),取其上清液与SD大鼠(新生5天)颅盖骨培养体系继续培养48h,以原子分光光度计法检测培养体系上清液中的Ca2+含量,从而判断不同牙源性病损在体外导致骨吸收作用的差异。同时采用放射免疫技术检测牙源性病损体外培养上清液中的骨吸收相关因子:白细胞介素6(IL6)、肿瘤坏死因子α(TNFα)、前列腺素E2(PGE2)、骨钙素(BGP)和降钙素(CT)等的含量。结果各组牙源性囊肿和肿瘤引起大鼠颅盖骨培养Ca2+析出的浓度显著高于空白组(P<0.01);OKC伴感染组Ca2+浓度显著高于OKC组和成釉细胞瘤组(P<0.05)。各组牙源性囊肿和成釉细胞瘤培养上清液中IL6、TNFα、PGE2和CT含量显著高于空白对照组(P<0.05);OKC组和OKC伴感染组IL6含量显著高于成釉细胞瘤组(P<0.05);OKC伴感染组CT含量显著高于OKC组和含牙囊肿组(P<0.05)。这些因子和Ca2+含量的相关性分析结果显示,IL6与钙值之间呈显著性正相关(P<0.01)。结论颌骨牙源性病损在体外可促进骨吸收,此作用可能与其产生的某些细胞因子有关。     

牙源性角化囊肿细胞增殖抗原和表皮生长因子受体表达

目的　探讨牙源性角化囊肿衬里上皮细胞的增殖特点。方法　采用免疫组化染色方法 ,对牙源性角化囊肿、成釉细胞瘤、含牙囊肿、正常口腔粘膜上皮中细胞增殖抗原 Ki- 6 7和表皮生长因子受体 (EGFR)的表达进行分析比较。结果　牙源性角化囊肿中 Ki- 6 7表达较含牙囊肿高 ,与正常口腔上皮相似 ;复发的与未复发的牙源性角化囊肿 Ki- 6 7指数无显著性差异。牙源性角化囊肿中 EGFR表达呈阳性。结论　牙源性角化囊肿上皮增殖活跃 ,上皮增殖生长可能与表皮生长因子家族有关。     

Overexpression and extra-mitochondrial localization of the chaperonin Hsp60 in ameloblastoma

ObjectivesAmeloblastoma is an odontogenic neoplasm of the mandible and maxilla with various histological types and subtypes. It has been reported that some ameloblastomas could arise from dentigerous cyst walls; thus, the development of ameloblastoma from dentigerous cysts may be due to differential protein expression. Our aim was to identify a membrane protein that is differentially expressed in ameloblastomas with respect to dentigerous cysts.MethodsWe analyzed the SDS-PAGE profiles of membrane proteins from ameloblastomas and dentigerous cysts. The protein in a band present in the ameloblastoma sample, but apparently absent in the dentigerous cyst sample was identified via mass spectrometry as the chaperonin Hsp60. We used western blotting and immunohistochemistry to analyze its overexpression and localization in ameloblastoma.ResultsWe found a differential band of 95 kDa in the membrane proteins of ameloblastoma. In this band, the chaperonin Hsp60 was identified, and its overexpression was corroborated using western blotting and immunohistochemistry. Hsp60 was localized in the plasma membrane of all ameloblastoma samples studied; in addition, it was found in the cell nucleus of the plexiform subtype of conventional ameloblastoma.ConclusionsOur results suggest that Hsp60 may be involved in ameloblastoma development, and could therefore be a potential therapeutic target for ameloblastoma treatment.     

Clinicopathological evaluation of 164 dental follicles and dentigerous cysts with emphasis on the presence of odontogenic epithelium in the connective tissue. The hypothesis of “focal ameloblastoma”

Objectives: Some ameloblastomas presumably originate from odontogenic epithelium within the connective tissue of dental follicles and dentigerous cysts. Therefore, it would seem reasonable to discuss as whether odontogenic epithelium proliferations, frankly displaying ameloblastomatous features (“focal ameloblastoma”), should be considered as an “early” ameloblastoma. Study Design: Histopathological reports from 164 dental follicles and dentigerous cysts from the Department of Oral and Maxillofacial Surgery/Oral Pathology of the VU Free University medical center in Amsterdam, The Ne-therlands, were reviewed. Histopathological slides from 39 cases reporting the presence of odontogenic epithelium within the connective tissue were re-evaluated in order to assess the possible presence of focal ameloblastomas. Results: Focal ameloblastomas were detected in one dental follicle and in two dentigerous cysts. During a follow-up period of 6, 8 and 22 years, respectively, no clinical signs of (recurrent) ameloblastoma have occurred in these patients. Conclusions: Focal ameloblastoma possibly represents the early stage of ameloblastoma development. Key words:Ameloblastoma, odontogenic epithelium, dentigerous cyst, dental follicle.     

Calretinin Expression in Unicystic Ameloblastoma: An Aid in Differential Diagnosis

Calretinin is a 29 kDa calcium-binding protein, which is widely expressed in the central and peripheral neural tissue. It has also been demonstrated in odontogenic epithelium during odontogenesis and in neoplastic odontogenic tissues. The lining epithelium of eight cases of unicystic ameloblastoma, six cases of dentigerous cyst, six cases of odontogenic keratocyst, reclassified as keratocystic odontogenic tumor (KCOT), and four cases of solid/multicystic ameloblastoma was examined for the expression of calretinin. No positive staining was observed in any of the dentigerous cysts and keratocystic odontogenic tumor linings. In comparison, coarse dark brown staining was seen in the stellate reticulum of solid multicystic ameloblastoma and more superficial epithelial layers of unicystic ameloblastoma. In conclusion, we have highlighted calretinin to be a specific immunohistochemical marker for neoplastic ameloblastic tissue that can be used as an important diagnostic aid in the differential diagnosis of unicystic ameloblastoma and cystic odontogenic lesions.     

单囊型成釉细胞瘤临床病理及凝集素免疫组织化学研究

目的 研究单囊型成釉细胞瘤的临床病理及凝集素免疫组织化学特点，探索有助于诊断和临别诊断的组织学标记物。方法 对４０例单囊型成釉细胞瘤行ＨＥ染色及组织学观察；并对其中的２５例行荆豆凝集素（ＵＥＡ－１）、兀鹰血凝集素（ＢＳＡ－１）免疫组织化学染色。结果 ４０例 单囊型成釉细胞瘤，组织学上可分为３个亚型：第一型５例（１２．５％），第二型２０例（５０．０％），第三型１５例（３７．５％）；ＵＥＡ－１、ＢＳＡ     

Unicystic ameloblastoma of the maxilla: a case report

Unicystic ameloblastoma is believed to be less aggressive and responds more favorably to conservative surgery than the solid or multicystic ameloblastomas. This report is a rare case of unicystic ameloblastoma of the maxilla that was treated by enucleation under suspicion of a radicular cyst related to a dens in dente. The neoplastic nature of the lesion became evident only when the enucleated material was available for histologic examination. With this report, the authors illustrate the importance and complexity of a differential diagnosis of lesions with a cystic aspect in the anterior region of the maxilla, among them - inflammatory radicular cysts, odontogenic keratocysts, adenomatoid odontogenic and unicystic ameloblastoma. Relevant diagnostic problems and choice of treatment of unicystic ameloblastoma are presented along with a review of the literature.     

袋形术或减压术治疗颌骨囊性病变

颌骨囊肿的袋形术或减压术最早由Partsch（1892）在德文文献中介绍,因此亦称Partsch Ⅰ式手术。在英文文献中,袋形术（marsupialization）和减压术（decompression）2种术语有时未能严格区分,但其内涵有所不同。袋形术是指采用手术方法去除一部分囊壁,并将其创缘与口腔黏膜缝合形成袋口状,使得囊腔与口腔相通。     

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

OBJECTIVES: The aim of the present study was to compare the proliferation index of the epithelial cells between odontogenic keratocysts (OKC), orthokeratinized odontogenic cysts (OOC), dentigerous cysts (DC), and ameloblastomas. MATERIALS AND METHODS: The proliferation index, employing a novel cell proliferation marker IPO-38, was studied by the immunohistochemical technique in 10 OKC, seven OOC, eight DC and 10 ameloblastomas. RESULTS: The ameloblastoma had no higher labeling index (LI) of IPO-38 than the OKC (P = 0.910) but had higher LI than the OOC (P = 0.001) and DC (P = 0.000); the OKC had higher LI than the OOC (P = 0.002) and DC (P = 0.000); and the OOC had higher LI than the DC (P = 0.011). IPO-38-positive cells in the OKC and OOC were located principally in the suprabasal cell layers while the ameloblastoma were found in the peripheral portion in particularly, the follicular and plexiform types. CONCLUSION: These findings support previous studies that the proliferation indices are useful in predicting the different biological behavior of the odontogenic lesions and the OKC should be regarded as a benign tumor rather than simply an odontogenic cyst.     

Lectin histochemistry of cystic jaw lesions: an aid for differential diagnosis between cystic ameloblastoma and odontogenic cysts

The binding sites for Ulex europaeus agglutinin I (UEA-I), Bandeirea simplicifolia agglutinin I (BSA-I), and peanut agglutinin (PNA) were comparatively examined in the surgical materials from 41 cases of cystic and solid ameloblastomas and 42 cases of non-neoplastic odontogenic cysts including dentigerous cyst, odontogenic keratocyst, and radicular cyst. In non-neoplastic cysts, most of epithelial lining layers gave positive binding with UEA-I and BSA-I. However, no positive reactions were obtained for these two lectins in the epithelial components of ameloblastoma, except for limited UEA-I binding to markedly keratinized tumor cells in four cases. PNA binding was irregular and did not make any clear distinction between ameloblastomas and cysts. The results suggest that the lectin staining for UEA-I and BSA-I is a useful histologic aid for differential diagnosis between cystic ameloblastoma and non-neoplastic jaw cysts.     

Cyst or Tumor? A systematic review and meta-analysis on the expression of p53 marker in Odontogenic Keratocysts

The odontogenic keratocyst (OKC) is a potentially aggressive odontogenic lesion and there is an ongoing debate regarding its biological behavior and classification. The present systematic review aims to assess the expression of the p53 protein in the odontogenic keratocyst in comparison to the dentigerous cyst and ameloblastoma.We searched MEDLINE, Web of Science and Scopus for immunohistochemical studies reporting OKC's, dentigerous cysts and solid/multicystic ameloblastomas. The Risk Difference between the lesions expressing the p53 was the effect measure and a P value < 0.05 was considered to provide evidence to the effect estimates.Results: The first hit retrieved 126 records. After duplicates removal, there were 84 articles, of which eighteen were assessed for eligibility. Thirteen articles were included in the meta-analysis, showing that OKC's have an estimated difference of 23% (P < 0.003) in the probability to express the p53 over dentigerous cysts, and an estimated difference of 4% (P = 0.28) in the probability to express the p53 over ameloblastomas.OKCs seem to behave more similarly to a tumor rather than an odontogenic cyst regarding its p53 expression and the classification of this lesion into Keratocystic Odontogenic Tumor should be carefully revaluated.     

Comparison of angiogenesis in keratocystic odontogenic tumours, dentigerous cysts and ameloblastomas

Objective:  The aim of the present study was to evaluate and compare angiogenesis in keratocystic odontogenic tumours, dentigerous cysts (DCs) and ameloblasomas using monoclonal antibody against CD34.
Materials and methods:  Microvessel density was assessed in a total of 53 cases including 20 keratocystic odontogenic tumours, 13 DCs and 20 ameloblastomas (14 solid and six unicystic variants). Microvessel density was expressed as the mean number of microvessels per high-power-field.
Results:  Statistically significant differences in mean microvessel density were observed between keratocystic odontogenic tumours, DCs and solid ameloblastomas ( P  < 0.001). Mean microvessel density was significantly higher in solid ameloblastomas compared with both keratocystic odontogenic tumours and DCs; and was also significantly higher in keratocystic odontogenic tumours than in DCs.
Conclusion:  Within the limitations of the present study, it can be suggested that angiogenesis may be one of the mechanisms possibly contributing to the different biological behaviours of keratocystic odontogenic tumours, DCs and solid ameloblastomas.     

Frequency of odontogenic cysts and tumors: a systematic review

A systematic review of the literature from 1993 to 2011 was undertaken examining frequency data of the most common odontogenic cysts and tumors. Seven inclusion criteria were met for the paper to be incorporated. In the preliminary search 5231 papers were identified, of these 26 papers met the inclusion criteria. There were 18 297 odontogenic cysts reported. Of these there were 9982 (54.6%) radicular cysts, 3772 (20.6%) dentigerous cysts and 2145 (11.7%) keratocystic odontogenic tumors. With the reclassification of keratocystic odontogenic tumor in 2005 as an odontogenic tumor, there were 8129 odontogenic tumors reported with 3001 (36.9%) ameloblastomas, 1163 (14.3%) keratocystic odontogenic tumors, 533 (6.5%) odontogenic myxomas, 337 (4.1%) adenomatoid odontogenic tumors and 127 (1.6%) ameloblastic fibromas. This systematic review found that odontogenic cysts are 2.25 times more frequent than odontogenic tumors. The most frequent odontogenic cyst and tumor were the radicular cyst and ameloblastoma respectively.     

Small Central Odontogenic Fibroma Mimicking Hyperplastic Dental Follicle and Dentigerous Cyst

Central odontogenic fibroma has been defined as a benign odontogenic tumor, representing the intraosseous counterpart of a peripheral odontogenic fibroma. The odontogenic fibroma is a rare tumor. Differential diagnosis of radiolucent lesions in the molar-premolar region of mandible which involve impacted tooth may include central odontogenic fibroma, hyperplastic dental follicle, dentigerous cyst, unicystic ameloblastoma, and keratocystic odontogenic tumor. We describe an example of a small central odontogenic fibroma mimicking hyperplastic dental follicle and dentigerous cyst, resulting in uneruption of a primary tooth.     

Ameloblastoma in young persons: a clinicopathologic analysis and etiologic investigation

Ameloblastoma, an odontogenic tumor of ectodermal origin, has been reported to arise, on rare occasions, in a primordial or dentigerous cyst of a young person. Numerous authors have suggested differing nomenclatures for these ameloblastomas (e.g., mural, unicystic, monocystic, intracystic, cystogenic, cystic, plexiform unicystic) and have sought to describe and classify the clinical and histopathologic features. These tumors have been characterized as a distinct variant exhibiting less aggressive behavior and a lower rate of recurrence than conventional ameloblastoma. Furthermore, various etiologic factors have been proposed for these cystic ameloblastomas, including (1) nonspecific irritational factors such as extraction, caries, trauma, infection, inflammation, or tooth eruption; (2) nutritional deficit disorders, and (3) viral infection. The files of the combined accessioned cases of Emory University's and Temple University's oral pathology laboratories were searched and a review of the literature was performed. Thirty-eight cases of mandibular ameloblastoma (37 intraosseous, 1 peripheral) in persons 19-year-old and younger were found from a combined total of 311 accessioned cases of ameloblastoma (12.2%). The average age at diagnosis was 10.4 years for the 18 males and 20 females. Of the 33 cases in which race was stated, 19 (57.6%) were white and 14 (42.4%) were black. In the 28 cases in which a clinical diagnosis was offered, fifteen (53.6%) were thought to be dentigerous cysts. Ten cases from patients less than 19 years old were investigated by means of an immunohistochemical staining technique for the detection of human papilloma virus (HPV) genus-specific structural antigen in formalin-fixed, paraffin-embedded tissue. Three of the ten cases (cases 31, 37 and 38) were positive for HPV capsid antigen, whereas none of ten randomly selected ameloblastomas in adults was positive. A discussion of the clinical and histopathologic comparative findings, with emphasis on treatment results and possible HPV etiology, is included. The preliminary nature of finding HPV in the tumor cells is stressed, with recommendation for further verification and typing with the more sensitive in situ hybridization technique.     

Developmental odontogenic cysts. An update1

This review paper reports recent advances in the subject of developmental odontogenic cysts, essentially those of the past decade, starting with reference to the new WHO classification (1). On keratocysts, the latest reported recurrence rates are assessed as are their mode of growth, immunocytochemistry, immunology, genetic studies, and work on specific keratocyst antigens. There is a critical account of the group of lesions which includes the gingival cyst of adults, lateral periodontal cyst, hotryoid odontogenic cyst and glandular odontogenic cyst, and their possible relationship to one another. On dentigerous cysts, reference is made to the relationship between them and deciduous teeth, as well as to their immunocytochemistry and immunology. Recent work on the unicystic ameloblastomas. their classification and prognosis, is assessed, as is the calcifying odontogenic cyst and its relationship with solid odontogenic tumours.