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.     

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.     

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.     

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.     

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.     

A review of 318 odontogenic tumors in Kaduna, Nigeria.

PURPOSE: To analyze 318 odontogenic tumors seen at a tertiary oral care center in Kaduna, Nigeria for comparison with findings in previous Nigerian and world records. MATERIALS AND METHODS: A retrospective survey of odontogenic tumors based on the classification of Kramer et al was undertaken at the Maxillofacial Unit, Ahmadu Bello University Teaching Hospital, Kaduna, Nigeria, from all histopathologically proven cases of tumors and tumor-like lesions of the oral and perioral structures. Data were retrieved from case notes, radiographs, histopathology results, and follow-up records. Information collected were used to complete a questionnaire and subjected to analysis. RESULTS: There were 990 tumor and tumor-like lesions of the oral and perioral structures, of which 318 were odontogenic tumors (32%). Twelve histopathologic types of odontogenic tumors were found with more benign (n=314; 99%) than malignant (n=4; 1%). Ameloblastoma made up 233 (73%) of the tumors, followed by odontogenic myxoma (n=38; 12%), ameloblastic fibroma (n=9; 3%), and the adenomatoid odontogenic tumor (2%). Three cases of calcifying odontogenic cyst were co-existent with ameloblastoma (2) and ameloblastic fibro-odontoma (1). Among 275 surgically treated odontogenic tumors, enucleation was performed in 64 cases (23%), dentoalveolar segment resection with preservation of lower border of the mandible (n=33; 12%), segmental resection (n=168; 61%), and composite resection (n=9; 3%); 1 case was deemed inoperable. At least 8 cases of ameloblastoma (13%) recurred out of 60 followed up. CONCLUSION: Ameloblastoma is a fairly common tumor of Nigerian Africans accounting for 73% of odontogenic tumors and 24% of all tumors and tumor-like lesions of the oral and perioral structures. Various forms of resection are practiced to eradicate the tumor in view of the late presentation in our environment. Patients in Nigeria do not often return for follow-up reviews. A minimum of 5 years of follow-up reviews are necessary after treatment of ameloblastoma.     

Odontogenic tumours, a collaborative retrospective study of 75 cases covering more than 25 years from Estonia.

INTRODUCTION: The aim of the present collaborative study was to analyse retrospectively the character of odontogenic tumours in Estonia, involving the entire Estonian population (1.4 million), and to compare their prevalence with the figures presented in similar reports from other countries. MATERIAL AND METHODS: All material for the retrospective study was retrieved from the files of the Departments of Maxillofacial Surgery in Tartu and Tallinn, Estonia, where all in/out-patients are treated from the whole country. The final diagnosis in each case of odontogenic tumour was based on the 1992 WHO histological criteria. RESULTS: A total of 75 odontogenic tumours was found, 74 (98.6%) of which were benign, and 1 (1.3%) was malignant. The frequency of odontogenic tumours in this study was the lowest ever reported. The most common tumours were odontoma (34.3%), followed by ameloblastoma with different subtypes (25.3%), ameloblastic fibroma (16%), odontogenic myxoma (12%) and benign cementoblastoma (8%). CONCLUSION: Odontogenic tumours are relatively rare in Estonia compared with the data from other countries.     

Epithelium-connective tissue junction in follicular ameloblastoma and ameloblastic fibroma: an ultrastructural analysis

The ameloblastoma and ameloblastic fibroma are tumors of odontogenic origin. During odontogenesis, there is a sequence of inductive stimulations, or interactions, between the epithelium of the enamel organ and the connective tissue of the dental papilla. We review 7 cases of follicular ameloblastoma and 1 case of ameloblastic fibroma under the electron microscope to investigate possible induction-stimulated changes at the epithelium-connective tissue junction. Thickening of the basal lamina by a granulo-filamentous material was a universal finding. Horizontal proliferation and convolutions of this thickened material were found in 2 ameloblastomas. The ameloblastic fibroma evidenced fine aperiodic fibers perpendicular to the basal lamina. These changes are consistent with attempted inductive stimuli directed toward tooth formation.     

Ameloblastie fibromas and related tumors in cattle

This article concerns rare odontogenic tumors that occur predominantly in the mandibular incisor region of young cattle and which have often in the past been referred to as ameloblastomas, or as the outdated synonym, adamantinoma. Twenty-two examples from the literature and two new ones were studied. Six consisted of epithelial islands which resembled those of ameloblastoma but which were located within a cellular fibrous connective tissue that was the second component of the tumor these mixed odontogenic tumors therefore represented ameloblastic fibromas, not ameloblastomas. Eight consisted of a combination of ameloblastic fibroma and odontoma and therefore were ameloblastic fibro-odon-lomas, and one was apparently malignant (ameloblastic fibro-odontosarcoma). Excluding this last lesion, these tumors should respond well to enucleation, like their human counterparts but to confirm this hypothesis, the margins of future examples should be carefully examined to determine that they are well-demarcated, not invasive. The microscopic features of the remaining 9 tumours could not be evaluated adequately, while another 17 tumors in cattle and water buffalo reported briefly could not be studied to any extent because of insufficient information.     

Relative frequency of intra-oral minor salivary gland tumors: a study of 380 cases from northern California and comparison to reports from other parts of the world

BACKGROUND: The relative frequency of individual intra-oral minor salivary gland tumors (IMSGT) is not well documented in the literature. The aim of this study was to determine the relative frequency and distribution of IMSGT in an oral pathology biopsy service and to compare the data with similar studies from different parts of the world. METHODS: Files from the Pacific Oral and Maxillofacial Pathology Laboratory of the University of the Pacific, San Francisco, California served as a source of material for this study. Files were systematically searched for all cases of IMSGT during a 20-year period. Tumors were classified according to the 2005 WHO classification of salivary gland tumors. RESULTS: IMSGT were identified in 380 (0.4%) cases of 92 860 accessed. This is the largest series of IMSGT from one source reported in recent years. Of the 380 tumors, 224 (59%) were benign and 156 (41%) were malignant. Of the benign tumors, pleomorphic adenoma (PA) was the most common (39.2%), followed by cystadenoma (6.3%), canalicular adenoma (6.1%), ductal papillomas (4.4%), basal cell adenoma (1.6%), and myoepithelioma (1.3%). Of the malignant tumors, mucoepidermoid carcinoma was the most common (21.8%), followed by polymorphous low-grade adenocarcinoma (7.1%), adenoid cystic carcinoma (6.3%), adenocarcinoma, not otherwise specified (NOS; 2.1%), acinic cell carcinoma (1.6%), clear cell carcinoma, NOS (1.0%), and carcinoma ex PA (0.5%). CONCLUSIONS: Studies related to the relative frequency of individual IMSGTs from different parts of the world are difficult to compare because many studies are outdated, the number of cases is small, the list of tumors is limited, and new entities are not included. To determine the true relative frequency, more studies should be conducted, on a large number of cases from one source, by experienced pathologists in the field of salivary gland tumors.     

Odontogenic lesions in opercula of permanent molars delayed in eruption

Opercula of permanent first and second molars delayed in eruption were investigated histologically to detect possible causes of eruption failure. The material comprised operation specimens from exposure of 74 non-erupted molars in 63 young individuals (34 boys, 29 girls). Eighteen of the 74 specimens (or 24.3%) were diagnosed as "classical" odontogenic tumors belonging to the following entities: ameloblastic fibroma (seven), ameloblastic fibrodentinoma (six), ameloblastic fibro-odontoma (four) and complex odontoma (one). Twenty-two specimens (or 29.7%) showed a hitherto unrecognized odontogenic lesion of hamartomatous character, termed odontogenic giant cell fibromatosis (OGCF). Thus, 54.1% of the specimens could be diagnosed as odontogenic tumors or hamartomas. Histomorphologic changes could not be detected in the remaining 34 specimens (45.9%). Odontogenic tumors were associated with unerupted first molars much more frequently than with second molars (ratio 8:1). The OGCF had a strong association with unerupted mandibular molars. Further, opercula of mandibular first molars frequently revealed odontogenic lesions whereas tissue overlying the crown of unerupted maxillary second molars often was reported as normal operculum.     

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。     

Ameloblastic fibroma in the midline of mandible: a case report

The ameloblastic fibroma (AF) is a rare benign mixed odontogenic tumor. It is composed of both epithelial and mesenchymal elements, but lacks of any calcified dental structures. Most of these tumors occur in the mandible and appears preferentially in the posterior portion of the dental arch with molar area predominates over premolar area. It is important to differentiate the lesion from ameloblastoma, since unlike the latter, it does not exhibit a locally invasive growth pattern. It is a well-circumscribed lesion and does not require the radical excision that may be necessary to effect cure with ameloblastoma. The present case report describes a 15-year-old patient with an ameloblastic fibroma in the symphysis of the mandible, a rare reported site. In the beginning of the article an extensive review of the previously published literature on ameloblastic fibroma has been made. In the later part, the diagnosis, differential diagnosis, histology and therapeutic procedures and postoperative follow up of the present case have been described.     

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.     

Ameloblastoma and its relationship to ameloblastic fibroma: their histogenesis based on an unusual case and review of the literature.

The present paper describes the relationship between ameloblastoma and ameloblastic fibroma deduced from a case diagnosed as "ameloblastoma combined with ameloblastic fibroma" arising in the mandible of a 5-year-old boy. Histologically, the tumor consisted of ameloblastoma in the central area and ameloblastic fibroma in the peripheral area; it clinically fits the characteristics of ameloblastic fibroma based on predominant age, manner of growth, and encapsulation. We reviewed the literature and discussed the relationship between ameloblastoma a ameloblastic fibroma in terms of tumorigenesis. It is assumed that ameloblastic fibroma can also be transformed into ameloblastoma, if the succeeding hard tissues are not formed, and the collagenous connective tissue substituting for the stromal mesenchymal tissue is formed by the inductive effect of the epithelial strands or other unknown factors. Several possibilities relative to the pathogenesis of ameloblastoma have been proposed by oral pathologists; however, to our knowledge, "ameloblastic fibroma can be transformed into ameloblastoma" has not hitherto been reported. The case we experienced here may be thought as an intermediate tumor pattern between ameloblastic fibroma and ameloblastoma.     

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.     

Ameloblastic fibroma: growth potentiality of odontogenic epithelium and coexpression of intermediate filament proteins in fibromatous cells

Four cases of ameloblastic fibroma are described immunohistochemically in terms of intermediate-sized proteins in both epithelial and mesodermal components. Keratin proteins were demonstrated by polyclonal anti-keratin antiserum (TK: detecting 41-65 kDa keratins) and 2 monoclonal antibodies to keratin (KL1: 55-57 kDa, PKK1: 44, 46, 52 and 54 kDa), and monoclonal antibodies to vimentin and desmin. Two types of odontogenic epithelial tumour cells were discriminated: undifferentiated odontogenic cells and common ameloblastoma cells. Keratin expression was found to be stronger in undifferentiated cells than in the ameloblastoma cells. Undifferentiated cells were PAS-positive, while ameloblastoma cells were negative. Fibroma cells were strongly positive for vimentin, and negative for desmin. Keratin proteins were also expressed slightly. Thus, coexpression of keratin and vimentin was seen in fibroma cells. Histogenesis is discussed from the standpoint of the distribution patterns of keratin and vimentin, as well as with respect to the histopathology.     

Ameloblastic fibroma: growth potentiality of odontogenic epithelium and coexpression of intermediate filament proteins in fibromatous cells

Four cases of ameloblastic fibroma are described immunohistochemically in terms of intermediate-sized proteins in both epithelial and mesodermal components. Keratin proteins were demonstrated by polyclonal anti-keratin antiserum (TK: detecting 41–65 kDa keratins) and 2 monoclonal antibodies to keratin (KL1: 55–57 kDa, PKK1: 44, 46, 52 and 54 kDa), and monoclonal antibodies to vimentin and desmin. Two types of odontogenic epithelial tumour cells were discriminated: undifferentiated odontogenic cells and common ameloblastoma cells. Keratin expression was found to be stronger in undifferentiated cells than in the ameloblastoma cells. Undifferentiated cells were PAS–positive, while ameloblastoma cells were negative. Fibroma cells were strongly positive for vimentin, and negative for desmin. Keratin proteins were also expressed slightly. Thus, coexpression of keratin and vimentin was seen in fibroma cells. Histogenesis is discussed from the standpoint of the distribution patterns of keratin and vimentin, as well as with respect to the histopathology.     

Odontogenic tumors in Mexico: A collaborative retrospective study of 349 cases

Reports about the frequency of odontogenic tumors are scarce, and diagnostic criteria used in the reports are not uniform. This article presents the results of a retrospective study of odontogenic tumors recorded in four services of diagnostic pathology in Mexico City (two dental schools, one cancer hospital, and one private oral pathology service). The final diagnosis in each case was based on the 1992 histologic criteria of the World Health Organization. The frequency of odontogenic tumors, expressed as a percent of all oral and maxillofacial specimens, ranged from 0.8% in the cancer hospital (0.02% of all biopsies) to 3.7% in the private oral pathology service. The frequency was identical for the two dental schools (2.5%). We found a total of 349 odontogenic tumors; of these, 345 were benign (98.8%), and 4 (1.1%) were malignant (3 were primary intraosseous carcinomas and 1 was a malignant ameloblastoma). The most frequently occurring tumors were odontoma (34.6%), ameloblastoma (23.7%), myxoma (17.7%), adenomatoid odontogenic tumor (7.1%), and calcifying odontogenic cyst (6.8%). Although relatively rare, odontogenic tumors are still an important cause of extensive surgical procedures in Mexico.     

Calcifying odontogenic cyst with ameloblastic fibroma: report of three cases

Although it is a rare event, odontogenic tumors such as ameloblastoma, ameloblastic fibroma (AF), ameloblastic fibro-odontoma, and odontoma have been reported associated with calcifying odontogenic cyst (COC). There are only four cases of COC with AF cited in the English literature. However, three of these four cases were either included in a review of a series of cases or reported as an abstract, and limited clinical and histological information was provided. We present three additional cases of COC with AF and discuss the management for this combined lesion. Because COC is known for its histologic diversity and variable clinical behavior, and the clinical significance of an association of COC with AF is still unknown, we think it is valuable to report COC with AF with detailed clinical and pathological documentation.