Cisto odontogênico calcificante: um estudo multicêntrico / Calcifying odontogenic cyst: a multicenter study

Este estudo investigou a frequência do cisto odontogênico calcificante (COC) submetido à análise histopatológica em diferentes regiões geográficas do Brasil. Em uma análise retrospectiva (1953-2016), arquivos de biópsias de 10 centros de Patologia Oral e Maxilofacial localizados em diferentes estados do Brasil: Goiás, Minas Gerais, Pará, Rio de Janeiro, Rio Grande do Norte, Rio Grande do Sul, Santa Catarina e São Paulo foram analisados. Dados demográficos, características clinicopatológicas, aspectos radiográficos e tipos de biópsia foram avaliados descritivamente. O teste Mann-Whitney foi utilizado para determinar a associação entre sintomas, tempo de evolução e tamanho da lesão. A significância estatística foi estabelecida como p<0,05. O diagnóstico do COC foi de acordo com a classificação da Organização Mundial de Saúde (2017). Adicionalmente, uma revisão da literatura de série de casos de COC foi realizada em quatro bases de dados eletrônicas (PubMed, Medline Ovid, Web of Science e Scopus). Dos 198.350 espécimes de biopsias exploradas, 268 casos de COC foram avaliados, representando 0,1% das lesões orais dos centros estudados. Em geral, indivíduos do sexo feminino (n=142, 54.0%), na segunda década de vida (n=76, 31.0%) com acometimento da maxila (n=141, 54.4%) foram os mais afetados. O tamanho médio das lesões dos indivíduos sintomáticos foi maior que o dos casos assintomáticos (p=0,026). A revisão da literatura apresentou maior frequência dos casos de COC na Ásia (186 casos) e na Europa (68 casos), acometendo principalmente os homens (n=247, 56.2%) na terceira década de vida. O COC é uma lesão rara. Novos dados sobre as características clinicopatológicas de 268 casos foram adicionados à literatura. Os dados referentes ao gênero e idade dos pacientes brasileiros aqui relatados são diferentes dos achados de séries de casos relatados já na literatura. Este estudo fornece informações que podem ajudar os clínicos, patologistas e cirurgiões no diagnóstico e manejo do COC.

This study investigated the frequency of calcifying odontogenic cyst (COC) submitted to histopathological analysis in different geographic regions of Brazil. In a retrospective analysis (1953-2016), biopsy files of 10 Oral and Maxillofacial Pathology centers located in different states of Brazil: Goiás, Minas Gerais, Pará, Rio de Janeiro, Rio Grande do Norte, Rio Grande do Sul, Santa Catarina and São Paulo were analyzed. Demographic data, clinicopathological characteristics, radiographic aspects and treatment were evaluated descriptively. The Mann-Whitney test was used to determine the association between symptoms, evolution time and lesion size. Statistical significance was set as p<0.05. The diagnosis of COC was according to the classification of the World Health Organization (2017). In addition, a literature review of case series was carried out in four electronic databases (PubMed, Medline Ovid, Web of Science and Scopus). Of 198,350 specimens of biopsies analyzed, 268 cases of COC were surveyed, representing 0.1% of the oral lesions at the centers studied. Overall, female patients (n=142, 54.0%) in their second decade of life (n=76, 31.0%) and the maxilla (n=141, 54.4%) were more affected. The mean lesion size of symptomatic individuals was larger than that of cases without symptoms (p=0.026). The literature review showed a higher frequency in Asia (186 cases) and Europe (68 cases), mainly affecting men (n=247, 56.2%) in the third decade of life. COC is a rare lesion. Additional data on the clinicopathological features of 268 cases have been added to the literature. Data regarding gender and age of the Brazilian patients reported herein are different with findings of case series and retrospective studies reported in the literature. This study provides information that could help clinicians, pathologists, and surgeons in the diagnosis and management of COC.

A multicentre study of 268 cases of calcifying odontogenic cysts and a literature review.

OBJECTIVES: To investigate the frequency of calcifying odontogenic cysts (COCs) that have been submitted for microscopic examination from representative geographic regions of Brazil and to compare it with literature data. MATERIALS AND METHODS: A retrospective study was conducted on biopsies obtained from 1953 to 2016 at 10 Brazilian oral and maxillofacial pathology centres. A total of 198,350 biopsy specimens were analysed. Demographic data and histopathological diagnosis were evaluated descriptively and statistically. In addition, a literature review of case series was carried out in four electronic databases. RESULTS: A total of 268 cases of COC were surveyed, representing 0.1% of the oral lesions at the centres studied. Female patients in their second decade of life and the maxilla were more affected. The mean lesion size of symptomatic individuals was larger than that of cases without symptoms (p = 0.026). The literature review showed a higher frequency in Asia and Europe, mainly affecting men in the third decade of life. CONCLUSIONS: COC is a rare lesion. Novel data on the clinicopathological features of 268 cases have been added to the literature. Data regarding gender and age of the Brazilian patients reported herein contrast with findings of case series and retrospective studies reported elsewhere.

Calcifying odontogenic cyst, dentinogenic ghost cell tumor, and ghost cell odontogenic carcinoma: A systematic review.

BACKGROUND: The aim of this study was to integrate the available data published on calcifying odontogenic cyst (COC), dentinogenic ghost cell tumor (DGCT), and ghost cell odontogenic carcinomas (GCOCs) into a comprehensive analysis of their clinicoradiological features, treatment, and recurrence. MATERIALS AND METHODS: An electronic search with no publication date restriction was undertaken in October 2017 in the following databases: PubMed, Medline Ovid, Web of Science, and Scopus. Eligibility criteria included publications containing enough clinical, radiological, and histopathological information to confirm a definite diagnosis of these lesions. Data were evaluated descriptively. RESULTS: The literature review indicated a total of 234 publications reporting 367 COCs, 55 DGCTs and 44 GCOCs. These lesions have a predilection for Asian males. COCs mainly affect the mandible and patients in the second decade of life, DGCTs mostly affect the mandible and patients in the fourth decade of life, and GCOCs mostly affect the maxilla and patients in the fifth decade of life. CONCLUSION: Conservative surgery was the most common therapy for COCs and DGCTs, while radical surgery was most common for GCOCs. This study provides important and interesting data that could help clinicians and surgeons as well as oral and maxillofacial pathologists with the diagnosis and management of these lesions.

The Epidemiology, treatment, and complication of ameloblastoma in East-Indonesia: 6 years retrospective study

Background: Ameloblastoma is a neoplasm classified as a benign epithelial odontogenic tumor of the jaws, grow slowly and are locally invasive. The aim of the present study was to investigate the incidence, treatment, and complication of patients with ameloblastoma in East-Indonesia during six years retrospective study. Material and Methods: This retrospective study included 84 patients who were diagnosed with ameloblastoma from 2011 to 2016. There were 56 patients with treatment data available. Data from each patient, including gender, age, histologic type, the size of the tumor, radiologic form, tumor location, type of treatment, and complication were reviewed and analyzed retrospectively. Results: Fourteen patients were diagnosed with unicystic ameloblastoma (25%), thirty two patients with multicystic follicular ameloblastoma (57%) and ten patients with an unspecified multicystic ameloblastoma (18%). A total of about 35 patients were treated conservatively (62.5%) and 21 patients were treated radically (37.5%). Swelling was present as a pre-operative complication in all 56 cases (100%). There were no complaints concerning speech. Conclusions: The majority findings of the histologic type were multicystic ameloblastoma and their location were in the mandible. Most ameloblastoma were treated conservatively and reconstructions were made with only titanium plates and not bone graft (AU)

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A 44-year analysis of ghost cell odontogenic tumour subtypes in an Iranian population.

The objectives of our study were to evaluate the relative frequency of calcifying cystic odontogenic tumours (CCOTs), dentinogenic ghost cell tumours (DGCTs) and ghost cell odontogenic carcinomas (GCOCs), collectively known as ghost cell odontogenic tumours (GCOTs), in an Iranian population and to classify these lesions according to the 2005 WHO guidelines. Clinical/demographic data were recorded for all COCs referred to our Department from 1966 to 2010. H&E-stained slides were re-evaluated by two observers and all cases were reclassified according to the 2005 WHO guidelines. The male to female ratio of 37 retrieved COCs was 1.6 with most cases occurring intraosseously and in the second decade of life. Involvement of the mandible was significantly higher than the maxilla (P = 0.033). Histopathologically, most lesions demonstrated a cystic morphology and there were no GCOCs among our cases. Eight cases were followed for 4-20 years and 3 of them showed a total of 5 recurrences. Considering the variations among clinicopathologic reports of COC from different countries, presentation of epidemiologic data based on a universally accepted classification system would be extremely helpful in providing a better understanding of this lesion and comparing results between studies.

A prospective epidemiological study for odontogenic and non-odontogenic lesions of the maxilla and mandible in Queensland.

OBJECTIVES: Investigate the epidemiological profile for odontogenic and non-odontogenic intra-osseous lesions in the Queensland population (4.56 million) over 12 months. STUDY DESIGN: The following data were prospectively collected from all Queensland histopathology laboratories in 2011: gender, age at diagnosis, location of lesion, histopathological diagnosis of the lesion and the patient's postcode. RESULTS: Six-hundred and thirty-three lesions were collected, comprising 540 odontogenic cysts and 93 odontogenic tumors. Radicular cyst was the most frequently diagnosed lesion (247/540, 45.7%). The overall incidence of odontogenic tumors was 20.4/million. Keratocystic odontogenic tumor was the highest (15.1/million), followed by ameloblastoma (2.41/million) with odontoma and calcifying cystic odontogenic tumor having the same incidence (1.1/million). The 39 non-odontogenic intra-osseous lesions had an overall incidence of 8.55/million. Nasopalatine cysts had an incidence of 2.19/million, followed by fibrous dysplasia and central giant cell granuloma (1.97/million). CONCLUSIONS: Odontogenic tumors are 5 times less common than cysts. Non-odontogenic lesions are rare, with benign lesions 6.8 times more common than malignant lesions.

Thirty years clinicopathological study of 60 calcifying cystic odontogenic tumors in Iranian population.

AIM: To reevaluate all cases previously diagnosed as calcifying odontogenic cyst (COC) from the archives of the Department of Oral Pathology at Mashhad Faculty of Dentistry from 1978 to 2008. MATERIALS AND METHODS: Clinical histories and microscopic slides of all cases diagnosed as COC were reviewed and analyzed statistically. The information about patients such as age, sex, clinical features, radiographic view and other necessary data was gathered from biopsy files. RESULTS: The majority of cases occurred in mandible and four cases were peripherally. Thirteen cases were associated with other odontogenic tumors and 11 cases were odontoma type. In two cases, recurrence was reported after surgical treatment which underwent malignant transformation. CONCLUSION: Calcifying cystic odontogenic tumor (CCOT) in Iranian population occurs in younger age group with slightly male predilection and more mandibular, unicystic and simple type. CLINICAL SIGNIFICANCE: It is better to address the noncystic CCOT lesions with their specific terms in order to make histopathological characteristics clear.

Genetic screening for nevoid basal cell carcinoma syndrome in patients with a solitary keratocystic odontogenic tumour is not useful.

AIM: The aim of this study was to investigate the need for routine genetic counselling for identification of features of nevoid basal cell carcinoma syndrome (NBCCS) in patients presenting with a solitairy keratocystic odontogenic tumour (KCOT) of the jaws. METHODS: Sixty-nine patients treated for a solitary KCOT have been followed for the possible development of second KCOTs or other signs indicative of NBCCS. In addition, 11 randomly selected patients of this group were referred for genetic counselling, including identification of germ-line mutations in the Patched gene (PTCH gene). RESULTS: In none of the 69 patients clinical and radiographic manifestations of second KCOTs and/or other features associated with NBCCS were found during a follow-up period of 49.8 months. In the 11 patients referred for genetic counselling, there were no features indicative of the presence of NBCCS. No mutations in the PTCH gene could be identified. CONCLUSION: This study does not support the need for routine genetic counselling in patients presenting with a solitairy keratocystic odontogenic tumour of the jaws.

The pattern of odontogenic tumors in a government teaching hospital in the southern Indian state of Tamil Nadu.

OBJECTIVE: This hospital-based study was designed to provide demographic data on odontogenic tumors from the southern Indian population in the state of Tamil Nadu for comparison with pertinent series from other geographic regions. STUDY DESIGN: A total of 489 cases of odontogenic tumors registered over a period of 38 years (February 1970-March 2008) in the Department of Oral and Maxillofacial Pathology of Tamil Nadu Government Dental College and Hospital, Chennai, India, were retrieved from the files of histopathology registers and were retrospectively analyzed. RESULTS: Odontogenic tumors in the present study constituted 4.13% of all the 11,843 registered biopsies. The mandible was the most commonly affected anatomic location, with 362 cases (74.02%). Ameloblastoma with a predilection for posterior mandible was the most frequent odontogenic tumor (67.69%), followed by adenomatoid odontogenic tumor (9%), odontoma (7.77%), and calcifying odontogenic cyst (5.52%). The patients were affected over a wide age range of 5-75 years with a mean age of 32.64 years and peak occurrence in the second and third decades of life. Among the 489 cases, only 15 (3.07%) were malignant. CONCLUSION: The relative frequency of 4.13% of odontogenic tumors observed in this study, which is the largest series from this part of the world. Ameloblastoma formed the single most common tumor of all odontogenic tumors. This study observed both regional and geographic variations in the frequency and distribution of odontogenic tumors.

Cistos odontogênicos: estudo epidemiológico de 72 casos / Odontogenic cystis: epidemiological study of 72 cases

Introdução: os cistos odontogênicos constituem uma importante doença oral e maxilo-facial. Embora alguns possam resultar da inclusão de epitélio na linha de fusão de processos embrionários, muitos são limitados por epit[elio de origem odontogênica. Podem ser classificados em cistos de desenvolvimento e inflamatórios, de acordo com sua origem. Pacientes e método: os autores realizaram um estudo retrospectivo da incidência de cistos odontogênicos em pacientes atendidos no ambulatório do Serviço de Cabeça e Pescoço do Centro de Oncologia (CEON) do Hospital Universitário Oswaldo Cruz (HUCC)e registrados no Centro Integrado de Anatomia Patológica (CIAP), no período de janeiro de 1980 a janeiro de 2000. No presente estudo, 72 pacientes portadores de cistos odontogênicos foram arrolados. Foram analisados os indicadores tipo histopatológico, gênero, localização topográfica e faixa etária. Resultados: usando a classificação preconizada pela Organização Mundial da Saúde, 54,1% foram cistos dentígeros; 4,1% cisto odontogênico calcificante; 2,8% ceratocistos odontogênicos e 36,2% foram cistos de origem odontogênica, todavia, não identificados quanto ao tipo histopatológico. A maior parte das lesões císticas foi encontrada na maxila (61,1%). Conclusão: o conhecimento de sua origem e achados clinico-patológicos dessas lesões sáo aspectos básicos para realizar um diagnóstico precoce e um tratamento apropriado.

Introduction: the odontogenic cysts are an important oral and maxillofacial disease. Some cysts can be the result of epithelial inclusion into the fusion line of embryonic process. Howrever, others are limited by epithelium of odontogenic origin. They can be classified in developmental and inflammatory cysts according to their origin. Patients and methods: the authors performed the retrospective study of the incidence of odontogenic cysts in patients from the Service of Head and Neck Surgery, Centro de Oncologia (CEON), Hospital Universitário Oswaldo Cruz (HUOC) and registered in Centro Integrado de Anatomia Patológica (CIAP) from January, 1980 to January, 2000. A total of 72 patients with odontogenic cysts were enrolled in this study. The histopathologic type, gender, topographic place and age were analyzed. Results: according to the WHO classification, our findings were as following: dental cysts, 54.1%; calcified odontogenic cysts, 4.1%; apical periodontal cysts, 2.8%; odontogenic ceratocysts, 2.8%; and odontogenic cysts without histophatologic identification, 36.2%. Most part of the cystic lesions were found in the maxilla (61.1%). Conclusion: the knowledge of the origin and the clinic-pathological findings are important aspects in order to perform early diagnosis and adequate treatment.

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.

Range and demographics of odontogenic cysts diagnosed in a UK population over a 30-year period.

BACKGROUND: The aim of this study was to determine the range of all histologically diagnosed odontogenic cysts along with age range, sex distribution and site of presentation over a 30-year period. METHODS: All entries for odontogenic cysts occurring during 1975-2004 inclusive were retrieved and analysed for demographic data. RESULTS: A total of 55,446 specimens were received, of these 7121 (12.8%) specimens were diagnosed as odontogenic cysts. Radicular cyst was the most common diagnosis (52.3%), followed by dentigerous cyst (18.1) and odontogenic keratocysts (11.6%). CONCLUSIONS: Our study provides demographic data on a large series of odontogenic cysts in a European population. This is one of the largest series reported to date. Cysts such as the paradental cyst have a predilection for certain ages, sexes and sites. Odontogenic keratocysts and glandular odontogenic cysts have a marked propensity to recur as well as behave aggressively. It is essential that such lesions are detected as early as possible to minimize any necessary surgery.

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 study of 340 cases in a Brazilian population.

BACKGROUND: The aim of this study was to determinate the relative frequency of odontogenic tumors (OTs) in a Brazilian population and to compare this data with previous reports. METHODS: We reviewed the achieves of 19 123 specimens from oral pathology laboratory of Universidade Federal de Minas Gerais, from 1954 to 2004. Using the criteria of histologic typification published by the World Health Organization in 1992, we classified the OTs. RESULTS: A total of 340 OTs were found. The frequency of OTs comprises 1.78% of all pathologic specimens in our laboratory. The most frequent tumor was ameloblastoma (45.2%), followed by odontomas (24.91%), and myxomas (9.1%). CONCLUSIONS: Odontogenic tumors are uncommon lesions in this Brazilian population and malignant OTs are very rare. The relative frequency of various types of OTs, age, and gender distribution are similar to those reported in African, Asian but not to Chilean and North American series.

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: 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 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.