Hybrid odontogenic tumor of calcifying odontogenic cyst and ameloblastic fibroma

Odontogenic tumors composed of 2 distinct types of lesions are unusual. We report an odontogenic tumor that was composed of calcifying odontogenic cyst and ameloblastic fibroma that occurred in the right posterior maxilla of a 22-year-old Korean woman. The tumor had a cystic component with an ameloblastic epithelial lining and conglomerates of so-called ghost cells, and there were deposits of dentinoid material adjacent to the cyst. These are features characteristic of calcifying odontogenic cyst. Enamel organ-like epithelial islands were observed within a dental papilla-like stroma of the cyst wall. Additionally, a solid portion of the tumor had characteristic features of ameloblastic fibroma, i.e., a myxoid cellular stroma with numerous elongated islands of ameloblastic epithelium. Ghost cell masses were found in the area of ameloblastic fibroma as well. The distribution of the ghost cells suggests that this is a hybrid lesion rather than a collision tumor.     

Expression of odontogenic ameloblast-associated protein, amelotin, ameloblastin, and amelogenin in odontogenic tumors: immunohistochemical analysis and pathogenetic considerations

Screening for expression of amelogenesis-related proteins represents a powerful molecular approach to characterize odontogenic tumors and investigate their pathogenesis. In this study, we have examined the presence and distribution of odontogenic ameloblast-associated protein (ODAM), amelotin (AMTN), ameloblastin (AMBN), and amelogenin (AMEL) by immunohistochemistry in samples of adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor (CEOT), developing odontoma, ameloblastoma, calcifying cystic odontogenic tumor (CCOT), ameloblastic fibroma (AF), myxoma, odontogenic fibroma (OF), and reduced enamel epithelia (REE). Positive results were obtained in those tumors with epithelial component, except for AF, OF, and ameloblastoma. ODAM was found around mineralized structures (dystrophic calcifications) and CEOT's amyloid, whereas AMTN stained the eosinophilic material of AOTs. The CCOT transitory cells to ghost cells were strongly positive with all proteins except AMEL, and the REE as well as odontomas showed immunoexpression for ODAM, AMTN, AMBN, and AMEL similar to those found in normal rat tooth germs. Based on these results, some histopathogenetic theories were formulated.     

Odontogenic ghost cell carcinoma: a case report with reference to the relation between apoptosis and ghost cells

The neoplastic variant of calcifying odontogenic cyst has various designations, and its malignant counterpart has been reported as aggressive epithelial odontogenic ghost cell tumor or odontogenic ghost cell carcinoma. We present a case of odontogenic ghost cell carcinoma with reference to the relation between the ghost cells and apoptosis. A 33-year-old man complained of a mandibular mass. The mass occupied the entire right side of the mandible with destruction of both buccal and lingual bone. The mass also infiltrated into submandibular and sublingual spaces. Histologically, the mass was composed of a solid proliferation of hyperchromatic and pleomorphic epithelial cells with abnormal mitoses. Islands of ghost cells were frequently admixed with nucleated cells, and there were foci of ameloblastic differentiation. Immunohistochemical stains for cytokeratins, involucrin, and apoptosis-related proteins such as Bcl-2, Bcl-X(L), and Bax were done. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) assay was also performed. The nucleated cells adjacent to the ghost cells expressed cytokeratins and involucrin, but the ghost cells had no reaction. Bcl-2 was negative. Both Bcl-X(L) and Bax were demonstrated in the nucleated cells adjacent to the ghost cells. The ghost cells exhibited Bax protein. Some nucleated cells adjacent to the ghost cells were positive with TUNEL assay. The above results indicate that ghost cells undergo abnormal terminal differentiation as an apoptotic process.     

Odontogenic tumors: analysis of 706 cases.

From a total of 54,534 oral biopsy specimens, 706 (1.3%) odontogenic tumors were retrieved and reviewed. Odontomas comprised more than 65% of the odontogenic tumors, ameloblastomas about 10%, and the remaining six categories of odontogenic tumors accounted for approximately 25% of the lesions. The distribution by age, sex, and location of these tumors generally supported the data from other previously reported cases. A possible variant of the calcifying epithelial odontogenic tumor was described, and instances of two granular cell ameloblastic fibromas were reported. The myxomas as a group were characterized histologically more by residual bony trabeculae than by the presence of odontogenic rests. Because the clinical, histological, and behavioral features of the ameloblastic fibroma and ameloblastic fibro-odontoma were similar, these lesions were considered to be essentially the same. From limited follow-up information, the ameloblastoma was the only lesion that recurred. With the exception of one ameloblastoma found in the lung, no malignant odontogenic tumors were encountered.     

Odontogenic tumors: a review of 319 cases in a Nigerian teaching hospital

OBJECTIVE: This study sought to determine the relative frequency of odontogenic tumors in a Nigerian population and to compare these data with previous reports. STUDY DESIGN: Records of patients seen at the Lagos University Teaching Hospital between January 1980 and December 2003, with histologic diagnosis of odontogenic tumors (based on World Health Organisation classification, 1992), were analyzed. RESULTS: Odontogenic tumors constituted 9.6% of all the biopsies of oral and jaw lesions seen within the period under study. Three hundred and eight (96.6%) were intraosseous, and 11 (3.4%) were peripheral (peripheral odontogenic fibroma=7; peripheral myxoma=3; peripheral ameloblastoma=1). The mean age of patients was 29.9+/-15.6 years (range, 4-85 years). Among these cases, 96.6% of the tumors were benign and 3.4% were malignant. Ameloblastoma with predilection for the mandible was the most frequent odontogenic tumor (63%), followed by adenomatoid odontogenic tumor (AOT) (7.5%), myxoma (6.5%), calcifying epithelial odontogenic cyst (5.3%), and odontogenic fibroma (5.3%). More cases of malignant odontogenic tumors were seen than cases of calcifying epithelial odontogenic tumor and odontomas. The mean ages of patients with AOT, ameloblastic fibroma, and odontoma were significantly lower than those with ameloblastoma ( P<.05). No significant difference was found between the mean ages of patients with benign odontogenic tumors and those with malignant odontogenic tumors ( P=.058). CONCLUSIONS: Odontogenic tumors, especially ameloblastoma, are not considered rare among Nigerians, whereas odontoma, regarded as the most frequent odontogenic tumor in North and South America, is rare.     

Calcifying odontogenic cyst with ameloblastic fibro-odontome: one lesion or two?

Abstract. The calcifying odontogenic cyst is unusual in that it is frequently found in conjunction with the histologic features of a variety of other odontogenic conditions. Two cases are reported, one of which contained areas histologically similar to the ameloblastic fibro-odontome and also showed condensations of cells in the stroma beneath epithelial strands proliferating from the cyst lining. In both cases the "ghost cells" stained strongly for disulphide groups but only occasional areas were positive for sulphydryl groups. No amyloid or "amyloid-like" material was detected. As no part of the current name is specific to this lesion it is suggested that the nomenclature should be changed – perhaps to "ghost cell cyst".     

Pigmented lateral periodontal cyst and other pigmented odontogenic lesions

OBJECTIVE: To report a case of lateral periodontal cyst (LPC) with marked melanin pigmentation in a 38-year-old Black male and to discuss the phenomenon of melanin pigmentation in odontogenic cysts and tumors.
RESULTS: Histologically, the epithelial lining of the LPC contained an abundant amount of melanin granules throughout the entire epithelium. Ultrastructurally, epithelial cells contained mature melanosomes (stage IV melanosomes). Melanophages containing aggregates of melanosomes were identified in the connective tissue cyst wall. Perusal of the literature revealed that melanin pigmentation in odontogenic lesions is uncommon. Melanin has been reported in calcifying odontogenic cyst (18 cases), odontogenic keratocyst (8 cases), adenomatoid odontogenic tumor (3 cases), ameloblastic fibroma (3 cases), odontoma (2 cases), and amelobastic fibro-odon-toma, odonto-ameloblastoma, and odontogenic fibroma (I case each).
CONCLUSIONS: Almost all pigmented odontogenic lesions occurred in Blacks and Asians; they are almost non-existent in Whites. Thus, racial pigmentation probably plays an important role in such lesions.     

An immunohistochemical study of odontogenic mixed tumours

Five cases of odontogenic mixed tumour comprising of an ameloblastic fibroma, an adenomatoid odontogenic tumour, an odonto-ameloblastoma and two ameloblastic fibro-odontomas were immunohistochemically investigated. Odontogenic epithelial cells were fully positive for cytokeratin detected by antibody KL-1, although there were some differences in its intensity. In contrast, for tenascin, only immature dental papilla-like mesenchymal tissue, especially around the dental lamina-like odontogenic epithelium, was positive, while the myxomatous area and connective tissue were negative. Positive vimentin staining was observed in some areas of immature dental papilla-like cells as well as the basement membrane of odontogenic epithelium in the ameloblastic fibroma, suggesting that this tumour had developed at the early stage of tooth formation. Proliferating nuclear cell antigen-positive cells were generally rarely seen, but were frequently observed in epithelial cells of the ameloblastic fibroma and odonto-ameloblastoma. These observations suggest that tumour cells in each odontogenic mixed tumour possess characteristic proteins associated with proliferation potential and that ameloblastic fibroma and odonto-ameloblastoma have higher proliferation potential among the tumours examined.     

Calcifying odontogenic cyst with ameloblastic fibro-odontome: one lesion or two?

The calcifying odontogenic cyst is unusual in that it is frequently found in conjunction with the histologic features of a variety of other odontogenic conditions. Two cases are reported, one of which contained areas histologically similar to the ameloblastic fibro-odontome and also showed condensations of cells in the stroma beneath epithelial strands proliferating from the cyst lining. In both cases the "ghost cells" stained strongly for disulphide groups but only occasional areas were positive for sulphydryl groups. No amyloid or "amyloid-like" material was detected. As no part of the current name is specific to this lesion it is suggested that the nomenclature should be changed--perhaps to "ghost cell dyst".     

Peripheral odontogenic fibroma. Report of 5 cases

The peripheral odontogenic fibroma (WHO type) is a relatively rare, benign, unencapsulated, exophytic gingival mass of fibrous connective tissue. Odontogenic epithelium is found within the gingival mass, but usually appears to play a minor role when compared to the fibrous component. According to the present concept, cases reported in the literature under the terms "odontogenic gingival epithelial harmartoma" "hamartoma of the dental lamina" and "peripheral ameloblastic fibrodentinoma" are actually examples of peripheral odontogenic fibroma. Review of the literature revealed only 30 acceptable cases that fit the present concept of peripheral odontogenic fibroma. Because of the paucity of reported cases, the histomorphological spectrum and the clinical features of this lesion have not yet been fully established. This article presents five new cases of peripheral odontogenic fibroma. The connective tissue ranged from markedly cellular to relatively acellular well collagenized. Islands and strands of epithelium were present in all five cases: in four they were scanty and in one abundant. A matrix of mineralized material was present in four cases. The peripheral odontogenic fibroma must be differentiated histologically from peripheral ossifying fibroma, which is a reactive lesion, and from the peripheral ameloblastoma and the calcifying epithelial odontogenic tumour.     

Expression of tenascin and nucleolar organizer region in ameloblastoma and ameloblastic fibroma

J Oral Pathol Med (2010) 39 : 223–229 Background: The aim of this study was to assess the expression, distribution and comparison of tenascin, a glycoprotein of the extracellular matrix in ameloblastoma and ameloblastic fibroma, both odontogenic neoplasms with diverse biological behavior and to understand the proliferative activity by using the morphometric analysis. Methods: Paraffin embedded tissue from 25 cases of odontogenic tumors i.e., ameloblastoma (n = 15) and ameloblastic fibroma (n = 10) were used. The expression of tenascin was evaluated using immunohistochemistry. Morphometric analysis of nucleolar organizer regions (NORs) from ameloblastoma and ameloblastic fibroma was carried out by silver staining. Results: A heterogeneous expression of tenascin was found in ameloblastoma which was mainly localized at the epithelial–mesenchymal interface and a patchy distribution was observed in the stroma (80%), while strong positivity was observed in the stroma and at the basement membrane zone of ameloblastic fibroma (100%). argyrophilic nucleolar organizer regions (AgNORs) revealed higher mean counts in ameloblastoma (3.093 ± 0.902) when compared with those of ameloblastic fibroma (1.553 ± 0.250). Ameloblastoma presented more than two NORs (two to five) per nucleus in majority of the cells, while ameloblastic fibroma exhibited only one NORs per nucleus. Conclusions: Expression of tenascin in these neoplasms suggest that it could play a role in epithelial‐ mesenchymal interaction, while AgNORs reveal that ameloblastomas are more aggressive when compared with ameloblastic fibromas.     

Peripheral ameloblastic fibroma of the maxilla: report of a case and review of the literature

Peripheral odontogenic lesions are considered to be rare within the classification of odontogenic tumors. Also referred to as extraosseous or soft tissue odontogenic tumors, peripheral odontogenic tumors share the same histopathologic characteristics of their central or intraosseous counterparts. Ameloblastic fibroma is a rare odontogenic tumor that arises from both odontogenic epithelium and connective tissue. Only 2 cases of peripheral ameloblastic fibroma have been reported in the English-language literature, one of which did not show the classic features of an ameloblastic fibroma. In this report, we describe a rare case of a peripheral ameloblastic fibroma in the maxilla of a 3-year-old girl.     

Malignant ameloblastoma or ameloblastic carcinoma

The World Health Organization defines malignant ameloblastoma as a lesion exhibiting features of an ameloblastoma in primary and metastatic growths. To cases collected from the literature we have added two of our own cases in which features of an ameloblastoma were coupled with malignant behavior. It was noted that the diagnosis of “malignant ameloblastoma” is at present used in a rather indiscriminate way, resulting in the grouping of lesions that exhibit considerable differences in biological behavior and histomorphology. This might be due to the fact that the WHO classification emphasizes metastasis as a diagnostic criterion but is rather vague in defining histopathologic aspects. It is advocated that the term malignant ameloblastoma be reserved for those lesions that, in spite of a seemingly innocuous histology, have given origin to metastatic growths, while the WHO classification should be modified to include ameloblastic carcinoma as a diagnostic term for lesions that combine features of an ameloblastoma with a less-differentiated histomorphology.     

Hybrid odontogenic ghost cell tumor and cutaneous pilomatrixoma: a highly unusual coexistence

This article describes the first published case of coexistence in a child of a rare hybrid odontogenic ghost cell tumor and a solitary cutaneous pilomatrixoma. An 11-year-old boy presented with a large well-defined unilocular radiolucent lesion in the right posterior mandible. Marsupialization followed by enucleation of the remaining lesion at a later period was the treatment of choice. Histopathologic analysis revealed a hybrid tumor demonstrating areas identical to calcifying cystic odontogenic tumor, ameloblastoma, ameloblastic fibro-odontoma, ameloblastic fibromyxoma, and adenoid odontogenic tumor. A cutaneous nodule was also removed from the facial area and demonstrated classic features of pilomatrixoma on histopathology. Sixteen cases of hybrid calcifying cystic odontogenic tumor associated with odontogenic tumors other than ameloblastomas and odontomas are referred in the literature to date. Young males are frequently affected, and the mandible is the most common site of involvement. The occurrence in the same patient of 2 distinctive entities, which both demonstrate ghost/shadow cells, may be a coincidental finding or suggest a common origin regarding the histogenesis of these cells. Alternatively, future molecular studies may clarify possible genetic or/and predisposing factors for the development of these lesions.     

Immunohistochemical demonstration of bone morphogenetic protein in odontogenic tumors

The aim of the present study was to describe the expression and distribution of bone morphogenetic protein (BMP) in odontogenic tumors by immunohistochemistry using monoclonal antibody against bovine BMP (BMPMcAb). Eight types of odontogenic tumors (44 cases), including ameloblastoma (20 cases), cementifying fibroma (8 cases), benign cementoblastoma (5 cases), dentinoma (3 cases), compound odontoma (2 cases), adenomatoid odontogenic tumor (2 cases), calcifying epithelial odontogenic tumor (2 cases) and odontogenic fibroma (2 cases), were studied. The results showed that, according to the immunostaining pattern of BMPMcAb, tumors could be classified into two types: all cementifying fibro-mas, benign cementoblastomas. Dentinomas, odontogenic fibromas. and compound odontomas demonstrated a positive reaction, whereas all ameloblastomas, adenomatoid odontogenic tumors, and calcifying epithelial odontogenic tumors were negative. BMPMcAb-positive odontogenic tumors were those tumors with formation of enamel, dentin, cementum or bone. Therefore. BMP might play an important role in the formation of calcified dental tissues and the development of odontogenic tumors contaning such tissues.     

Calcifying odontogenic cyst. A review of ninety-two cases with reevaluation of their nature as cysts or neoplasms, the nature of ghost cells, and subclassification.

Ninety-two cases of calcifying odontogenic cyst (COC) were reviewed with special consideration of their nature as cysts or neoplasms, the nature of ghost cells, and classification on the basis of clinicopathologic features. The cases were divided into 79 (85.9%) cysts and 13 (14.1%) neoplasms. The cysts occurred as four variants: (1) nonproliferative COC (35 cases), characterized by a simple unicystic structure; (2) proliferative COC (17 cases), characterized by a cystic structure with multiple daughter cysts, extensive ghost cell formations, and marked tendency for calcification; (3) ameloblastomatous COC (11 cases), characterized by ameloblastoma-like, cyst-lining epithelium with ghost cells and calcifications; and (4) COC associated with odontoma (16 cases), which combined features of COC and odontoma. The neoplasms occurred as three variants: (1) ameloblastoma ex COC (two cases), which showed unifocal and multifocal intraluminal and intramural ameloblastoma proliferating from the COC-lining epithelium; (2) peripheral epithelial odontogenic ghost cell tumor (eight cases), which occurred in the gingiva and resembled peripheral ameloblastoma except for clustered ghost cells in the central portion of epithelial islands and the presence of juxtaepithelial dentinoid; and (3) central epithelial odontogenic ghost cell tumor (three cases). The latter showed ameloblastomatous or adenomatoid odontogenic tumor-like epithelial clusters with ghost cell formation and juxtaepithelial dentinoid. The clinical features of cystic and neoplastic variants were tabulated and described. On the basis of histopathologic features and their immunohistochemical reaction to polyclonal antikeratin antibody, it is suggested that ghost cells might be the result of coagulative necrosis.     

同源盒基因HOXC13在牙源性肿瘤中的表达

目的:检测同源盒基因HOXC13 mRNA在牙源性肿瘤中的表达,探讨其发生的意义。方法:采用原位杂交法检测47例成釉细胞瘤(ameloblastoma,AB)(原发29例,复发14例,恶变4例)、3例牙源性钙化囊性瘤(CCOT)、3例成釉细胞纤维瘤(AF)、2例牙源性钙化上皮瘤(CEOT)、10例牙源性角化囊性瘤(KCOT)的HOXC13 mRNA水平,同时选取7例正常口腔黏膜上皮作为对照。采用SPSS10.0软件包对数据进行χ2检验。结果:HOXC13 mRNA在AB中的阳性率为97.9%(46/47),CCOT中为100%(3/3),CEOT中为100%(2/2),KCOT上皮中为70.0%(7/10),正常口腔黏膜细胞中为42.9%(3/7),AB、KCOT、正常黏膜3组间差异显著(Ρ=0.001),但角化及颗粒样变退化细胞却为阴性。3例AF均为阴性。结论:牙源性肿瘤的发生、发展与HOXC13的高表达有关,且受其调控。HOXC13 mRNA在牙源性病损上皮中表达有异质性,该基因可促进上皮增殖,阻抑成釉细胞的终末分化,其丢失可导致上皮细胞角化和退变。     

Relative frequency of peripheral odontogenic tumors: a study of 45 new cases and comparison with studies from the literature

BACKGROUND: Peripheral (extraosseous) odontogenic tumors are rare, and reports in the literature have mainly been single case reports or a small series of cases. The aim of this study was to determine the relative frequency of peripheral (extraosseous) odontogenic tumors relative to one another and relative to their central (intraosseous) counterparts in an oral pathology biopsy service and to compare these data with information available in the literature. METHODS: The files of the Pacific Oral and Maxillofacial Pathology Laboratory of the University of the Pacific, San Francisco, CA, USA, served as the source of material for this study. Files were systematically searched for all cases of peripheral odontogenic tumors (POTs) during a 20-year-period. RESULTS: There were 91,178 cases accessed in which central and POTs were identified in 1,133 (1.24%), central tumors in 1,088 (1.2%), and peripheral tumors in 45 (0.05%). Peripheral tumors accounted for 4% of all 1133 central and POTs. Peripheral odontogenic fibroma (PODF) was the most common of the 45 POTs accounting for 51.1% (23 cases) followed by peripheral ameloblastoma (PA) 28.9% (13 cases) and peripheral calcifying cystic odontogenic tumor (PCCOT) 13.3% (six cases). Peripheral calcifying epithelial odontogenic tumor, peripheral ameloblastic fibroma, and peripheral ameloblastic carcinoma were also identified--each comprised 2.2% (one case each). PODF was more common than its central counterpart by a 1.4:1 ratio. This was the only peripheral tumor that was more common than its central counterpart. PA accounted for 9.3% of all ameloblastomas and PCCOT for 26% of all calcifying cystic odontogenic tumors. CONCLUSION: There is only scarce information in the literature on the relative frequency of POTs. Additional studies should be conducted to determine the true relative frequency. To ensure accuracy, pathologists with experience in the field of odontogenic tumors should conduct these studies. Intraosseous tumors that perforate through the bone to the gingival tissue, clinically presenting as 'peripheral tumors' should be excluded.     

Immunohistochemical detection and distribution of enamelysin (MMP-20) in human odontogenic tumors

Enamelysin is a tooth-specific protease that was initially isolated from porcine enamel organ and subsequently from human odontoblasts. Since this protease is thought to play important roles in tooth development, the evaluation of enamelysin in odontogenic tumors may aid our understanding of the histogenesis and cell differentiation of such lesions. A monoclonal antibody (203-1C7) was generated against synthesized human enamelysin oligopeptide and was used to assess the immunolocalization of enamelysin in healthy developing tooth germs and various types of odontogenic lesions. In tooth germs, enamelysin expression was detected only in the secretory enamel. Thus, 203-1C7 may serve as an enamel-specific marker in the late stage of enamel matrix development and calcification. In odontogenic lesions, strong enamelysin staining was demonstrated in the immature enamel matrix of ameloblastic fibro-odontomas and odontomas. Furthermore, enamelysin was also detected in globular amyloid masses and calcified foci in calcifying epithelial odontogenic tumors, hyaline droplets, small and large mineralized areas in adenomatoid odontogenic tumors, and a portion of ghost cells in calcifying odontogenic cysts. Positive reactivity was also observed in selected tumor cells in some of these tumors. No intracellular staining for enamelysin was detected in ameloblastomas or the ameloblastic portion of ameloblastic fibro-odontomas. Also, enamelysin was not detected in dentin, dysplastic dentinoid hyaline matrices, and cementum that were present within the tumors examined. Thus, taken together, our results suggest that the enamelysin-specific monoclonal antibody (203-1C7) may be utilized as a marker of early enamel development and that enamelysin may be involved in the pathogenesis of specific odontogenic tumors.     

Epulides in the dog: a review

This article is based on a review of the literature and the study of pathology sections obtained from various veterinary pathology laboratories. Epulis is a non-specific, clinical designation for a localized, exophytic growth on the gingiva. Four reactive epulides occur in human beings, namely focal fibrous hyperplasia (fibrous epulis). pyogenic granuloma. peripheral giant cell granuloma (giant cell epulis. and peripheral ossifying fibroma (calcifying fibrous epulisl). The first three also occur in dogs but only focal fibrous hyperplasia appears to be common. The peripheral ossifying fibroma has not yet been reported in dogs. Odontogenic tumors occurring on the gingiva (i.e., as epulides) are referred to as peripheral odontogenic tumors. Three types have been reported in dogs. One, the common fibromatous epulis. is equivalent to the rare peripheral odontogenic fibroma in human beings. Another, the acanthomatous epulis. appears to be a form of ameloblastoma but differs from the peripheral ameloblastoma in human beings in that it invades bone; its biological behavior is therefore that of the human intraosseous ameloblastoma. The third, a rare lesion, has been referred to in the veterinary literature as a calcifying epithelial odontogenic tumor, although it is not the canine counterpart of the human CEOT The term, amyloid-producing odontogenic tumor , has been suggested as being appropriate for this lesion.