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.     

Odontogenic tumors in Sri Lanka: analysis of 226 cases.

PURPOSE: The purpose of this study was to analyze the relative prevalence of odontogenic tumors in Sri Lanka and compare it with prevalences reported for other countries. PATIENTS AND METHODS: A total of 226 cases of odontogenic tumors reported by the Department of Oral Pathology, Faculty of Dental Sciences, University of Peradeniya between 1996 and 2002, were analyzed. RESULTS: The most prevalent tumor was ameloblastoma (69.8%); odontoma was the fourth most prevalent (4.5%). No gender predilection was seen, but the tumors occurred most frequently in the second to fifth decades of life (77.4%) and most commonly in the mandible (79.6%). CONCLUSIONS: The comparative data with statistically significant differences suggest a geographical difference in the relative prevalence of ameloblastoma among various continents. It is suggested that ameloblastoma most frequently occurs in the mandible (the posterior region) in all Asian, African, and South American countries.     

Odontogenic tumors: A collaborative study of 218 cases diagnosed over 12 years and comprehensive review of the literature

Objectives: The objective of this study was to analyze the frequency and distribution of odontogenic tumors (OTs) in the Cappadocia region of Turkey, and to compare the findings with those reported in the literature. Study Design: The records of the Oral and Maxillofacial Surgery and Pathology Departments at Erciyes University, with histologic diagnosis of odontogenic tumors (based on the World Health Organization classification, 2005), over a 12-year period, were analyzed. The relative frequency of different types of tumors was also analyzed and compared with the literature. Results: OTs in the present study constituted 2.74% of all the 7,942 registered biopsies. A total of 218 cases of OTs were collected and reviewed. Of these, (94.04%) were benign and (5.96%) were malignant. The mandible was the most commonly affected anatomic location, with 170 cases (77.9%). Ameloblastoma with a predilection for the posterior mandible was the most frequent odontogenic tumor (30.28%), followed by keratocystic odontogenic tumor (19.5%), odontoma (13.4%), and odontogenic myxoma (8.5%). Conclusions: OTs are rare neoplasms and appear to show geographic variations in the world. In Cappadocia, Turkey, they are more common in the mandible, with ameloblastoma followed by keratocystic odontogenic tumors with the incidences observed in the present study being similar to those of previous studies from Asia and Africa, and in contrast to those reported from American countries. Key words:Odontogenic tumors, WHO classification, prevalence, jaws.     

Relative frequency of central odontogenic tumors: a study of 1,088 cases from Northern California and comparison to studies from other parts of the world.

PURPOSE: To determine the relative frequency of central odontogenic tumors in relation to all biopsy specimens and to one another in an oral pathology biopsy service and to compare the data with previous studies from different parts of the world. METHODS: Files from the Pacific Oral Pathology Laboratory of the University of the Pacific, San Francisco, CA served as a source of material for this study. Files were systematically searched for all cases of central (intraosseous) odontogenic tumors during a 20-year period. RESULTS: Central odontogenic tumors were identified in 1,088 (1.2%) cases out of the 91,178 accessed. Individually, of all odontogenic tumors, 75.9% were odontomas. The prevalence of the remaining tumors appears to be a rare occurrence. The second most common was ameloblastoma (11.7%), followed by odontogenic myxoma (2.2%). Odontomas are considered hamartomas or developmental anomalies. When excluded from the list of individual odontogenic tumors, ameloblastoma is the most common (48.5%), followed by odontogenic myxoma (9.2%), adenomatoid odontogenic tumor (7.3%), ameloblastic fibro-odontoma (7.3%), ameloblastic fibroma (6.5%), calcifying odontogenic cyst (6.5%), and odontogenic fibroma (6.1%). Each remaining tumor comprises less than 4%. CONCLUSIONS: Studies related to the relative frequency of individual odontogenic tumors from different parts of the world are difficult to compare because most studies are outdated, the list of tumors is limited, and new entities are not included. To determine the real relative frequency, further studies should be conducted, especially in Western societies, by experienced pathologists in the field of odontogenic tumors.     

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 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.     

Odontogenic tumors: A demographic study of 759 cases in a Chinese population

Seven hundred fifty-nine cases of odontogenic tumors retrieved from the files of College of Stomatology, West China University of Medical Sciences were classified according to the World Health Organization's Histological Classification of Odontogenic Tumors and compared with similar reports from other countries. Among these cases, 93.9% of the tumors were benign and 6.1% were malignant. Ameloblastomas predominated (58.6%) with a predilection for the mandible, while odontomas, generally regarded as the most frequent odontogenic tumor in North America, only accounted for 6.7%, the fourth most common tumor in this series. The mandible and the maxilla were divided into eight anatomic regions, and the distribution of each odontogenic tumor type amongst these regions was recorded. The relative incidence of each tumor type, patient age and gender were also compared with data from other selected large series. Geographic differences were noted in the relative incidence of ameloblastoma, odontoma and malignant odontogenic tumors among the Chinese/African, North American and Turkish/German groups. Ameloblastoma and malignant odontogenic tumors are not considered rare in a Chinese population.     

Immunoexpression of MMPs-1, -2, and -9 in ameloblastoma and odontogenic adenomatoid tumor

Objective:  The aim of this study was to evaluate and compare the expression of metalloproteinases-1, -2, and -9 in solid ameloblastoma and adenomatoid odontogenic tumor.
Methods:  A total of 20 cases of solid ameloblastoma and 10 cases of adenomatoid odontogenic tumors were selected and immunohistochemically assessed. Metalloproteinases-1, -2, and -9 immunoexpression and their distribution pattern were noted and semiquantitatively scored. The scores obtained were statistically analyzed.
Results:  Matrix metalloproteinase (MMP)-1 showed a predominant expression in both tumors and was found in stroma and parenchyma. For MMP-2, there was a varied expression, with 80% and 60% of immunoreactive tumor cells in ameloblastoma and adenomatoid odontogenic tumor respectively. Regarding stromal cells, 65% of ameloblastomas and 80% of adenomatoid odontogenic tumors showed positivity. There was immunoexpression of the MMP-9 in parenchymal and stromal cells in all cases of both tumors analyzed. A statistically significant difference in the expression of MMP-1 in relation to the expression of MMP-2 and -9 in ameloblastomas ( P  < 0.001) was observed.
Conclusion:  The results suggest that these metalloproteinases are related to growth and progression of tumors analyzed, and particularly in ameloblastoma, its highest aggressiveness may be, in part, a result of the active participation of the stromal cells and their products, such as the MMPs studied.     

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: A Retrospective Study in Egyptian population using WHO 2017 classification

Background Odontogenic tumors (OTs) are considered important among oral lesions because of their clinicopathological heterogeneity and variable biological behavior. The purpose of this retrospective cross-sectional study was to evaluate the frequency and distribution of different types of odontogenic tumors based on the current 2017 WHO Classification of Head and Neck Tumors over a period of 5 years. This was achieved by reviewing the records of Cairo''s educational hospitals and institutions and comparing the results with findings in the literature.Material and Methods The records of patients diagnosed with odontogenic tumors were obtained from six educational hospitals and a single institute in Cairo which included: Oral and Maxillofacial Pathology Department, Faculty of Dentistry, Cairo University; General Pathology Department, Faculty of Medicine, Cairo University; Oral Pathology Department, Faculty of Dentistry, Ain Shams University; Eldemerdash Hospital, Ain Shams University; El-Sayed Galal Hospital, Al-Azhar University; Ahmed Maher Teaching Hospital and National Cancer Institute. These records were reviewed over a 5-year (2014-2018) period and the odontogenic tumors were investigated for frequency, age, gender and site. The data were recorded, then analyzed using SPSS software.Results Intraosseous (central) odontogenic tumors constituted 2.56% of all 8974 registered oral and maxillofacial biopsies. A total of 230 cases of OTs were collected and reviewed. Of these, 97.8% were benign and 2.17% were malignant. The mandible was the most commonly affected anatomic location. Ameloblastoma, with a predilection for the posterior mandible, was the most frequent odontogenic tumor (55.65%), followed by cemento-ossifying fibroma (14.78%) and odontoma (9.13%). Females were more commonly affected than males. Most of the patients were in the third and fourth decades of life. There were no peripheral odontogenic tumors diagnosed in this period.Conclusions Some similarities and differences between our findings and those of previous studies of various populations were witnessed. OTs may greatly diverge according to the version of the classification used and by the sample size of the study. Retrospective analysis of the relative frequency of OTs in different countries will be helpful in enhancing the understanding of OTs, which is important for both oral maxillofacial surgeons and pathologists. Key words:Odontogenic tumors, epidemiology, world health organization classification, oral pathology.     

Neoplastic potential of odontogenic cysts

Odontogenic cysts and tumors are distinct entities and quite a common occurrence in the jaw bones. The lining of odontogenic cysts shows a potential for neoplastic transformation to non odontogenic malignancies like squamous cell carcinoma and mucoepidermoid carcinoma, and odontogenic tumors like ameloblastoma and adenoamatoid odontogenic tumor (AOT). AOT is a benign, epithelial odontogenic tumor, common site being the anterior maxilla. Its origin from a dentigerous cyst and in the mandible is rare. A case of an AOT arising from a dentigerous cyst associated with an impacted permanent mandibular left lateral incisor is reported.     

Mandibular ameloblastoma: analysis of surgical treatment carried out in 60 patients between 1977 and 1998

Ameloblastoma, a benign tumor of odontogenic type, represents 10% of all tumors of the jawbone. It is localized in the mandible in 80% of cases and in the upper jaw in the remaining 20%. In every case, the selection of the surgical treatment to be applied must consider some fundamental elements, including the age and general state of health of the patient, the clinicopathological variant, and the localization and extent of the tumor. In addition, it is necessary to evaluate whether the neoplasm to be treated is a primitive lesion or a recurrence. Although ameloblastoma has relative histological characteristics of benignity, this neoplasm has a high percentage of local recurrence and possible malignant development when treated inadequately. The aim of this study was to carry out a follow-up of 60 patients treated for ameloblastoma of the mandible between 1977 and 1998, analyzing the problems faced in removing this benign neoplasm and those concerning reconstruction of the surgical defect.     

Ectodermal odontogenic tumours: analysis of 197 Nigerian cases

This article presents a clinico-pathologic analysis of 197 cases of ectodermal odontogenic tumours archived in the Lagos University Teaching Hospital, Lagos Nigeria over a 21-year period. They were categorized according to the WHO classification of odontogenic tumours. Of the 197 cases, 182 (92.3%) were benign while 15 (7.6%) were malignant. Central ameloblastoma, which accounted for 88.3% in this series, was the most common benign neoplasm demonstrating predilection for males (58.6%) and the mandible (83.3%). The mean age of occurrence (+/-SD) was 31.00 +/- 13.9 (range 9-82 years). Similarly ameloblastic carcinoma was the most prevalent malignant tumour (5.6%) with a predilection for females (63.6%) and the mandible (81.8%). The mean age of occurrence (+/-SD) was 30.1+/- 20.7 (range 16-85) years. Follicular ameloblastoma was found to be the commonest histologic subtype seen in Nigeria.     

Osteogenic sarcoma arising adjacent to a long-standing ameloblastoma. A case report

Ameloblastoma is an uncommon odontogenic tumor usually occurring in the mandible. Rarely do other primary tumors occur with or arise from ameloblastoma. We describe a patient with simultaneous osteogenic sarcoma of the maxilla and recurrent ameloblastoma.     

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 tumors: a retrospective study of four Brazilian diagnostic pathology centers

Objective: This article presents the results of a retrospective study of the frequency and classification of odontogenic tumors recorded at four centers of diagnostic pathology in Rio de Janeiro, Brazil. Study Design: All medical records and microscopic slides of odontogenic tumor specimens for the years 1997 to 2007 were retrieved from the files of four services of diagnostic pathology in Rio de Janeiro City. Diagnoses were re-evaluated and the tumors classified according to the latest (2005) World Health Organization Classification of Tumors. Results: A total of 201 odontogenic tumors were found among 15,758 oral biopsies (1.3%). The frequencies of these tumors at the four centers ranged from 0.5% at the National Cancer Institute to 3.3% in a private laboratory. Chi-square analysis revealed statistically significant differences (p<0.05) between the proportions of odontogenic tumors in the studied centers. Of these, 94.5% were benign and 5.5% were malignant. Keratocystic odontogenic tumor (32.3%) was the most frequent lesion, followed by ameloblastoma (29.8%) and odontoma (18.4%). Conclusions: Odontogenic tumors are uncommon in Brazil. Different pathology laboratories reported divergent frequencies of odontogenic tumors, which may reflect institutional specializations and the patient populations served. Key words:Odontogenic tumors, jaw neoplasms, epidemiology, WHO classification.     

Proliferating cell nuclear antigen (PCNA) and p53 protein expression in ameloblastoma and adenomatoid odontogenic tumor

In this study, proliferating cell nuclear antigen (PCNA) and p53 protein expressions were analyzed in 16 cases of ameloblastoma and 8 cases of adenomatoid odontogenic tumor (AOT). The cases of ameloblastoma consisted of solid type tumors and histologic arrangements of different subtypes were observed. In some specimens, more than one histologic subtype was identified in the same lesion, and each tumor was categorized according to the predominant cell pattern. The odontogenic tumors were grouped as follows: follicular ameloblastoma (n=7), plexiform ameloblastoma (n=4), acanthomatous + follicular ameloblastoma (n=3), basal cell ameloblastoma (n=2), adenomatoid odontogenic tumor (n=8). PCNA immunohistochemical expression revealed stronger quantitative labeling index for the follicular ameloblastoma, while for p53 protein the strongest quantitative labeling index was detected in the plexiform type. Nevertheless, statistical analysis using ANOVA and Tukey's test did not detect significant differences (p>0.05) among the histologic subtypes of ameloblastoma. The findings of this study suggest that the different histologic patterns of ameloblastoma did not show a direct correlation with their clinical behavior and consequently with the prognosis of the cases. The results also indicated that the ameloblastoma has greater proliferative potential than the AOT, which can contribute to explain its more aggressive and invasive characteristics.     

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.     

Peripheral epithelial odontogenic tumors: a review

Peripheral (extraosseous or soft tissue) odontogenic tumors are rare lesions that occur in the soft tissue overlying the tooth-bearing areas of the mandible and the maxilla. A review of the English-language literature revealed only 48 well-documented cases of peripheral epithelial odontogenic tumors. Thirty-two were peripheral ameloblastomas; six were peripheral adenomatoid odontogenic tumors; nine were peripheral calcifying epithelial odontogenic tumors; and one was a peripheral squamous odontogenic tumor. An additional four cases were reported as peripheral ameloblastomas in extragingival locations, but their odontogenic origin is debatable. Although the peripheral ameloblastoma is histologically similar to its central counterpart, it differs in its clinical features and biologic behavior. It does not exhibit an aggressive, destructive behavior and does not invade the underlying bone. Conservative excision of the tumor with minimal but adequate margins is the treatment of choice and recurrences are uncommon. This benign biologic behavior appears to be true also for lesions diagnosed as peripheral calcifying epithelial odontogenic tumors and undoubtedly is true for the peripheral adenomatoid odontogenic tumors.