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.     

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提要：外周性牙源性肿瘤又称骨外型牙源性肿瘤或软组织牙源性肿瘤,主要发生在牙龈,包括牙源性真性肿瘤及错构瘤。外周性牙源性肿瘤约占所有牙源性肿瘤的4%左右,英文文献表明其中外周性牙源性纤维瘤最多见,其次是外周性成釉细胞瘤及外周性牙源性钙化囊性瘤。外周性牙源性肿瘤临床上容易与牙龈发生的炎症性或反应性病变相混淆,明确诊断依赖组织病理学检查。外周性牙源性肿瘤不包括骨内型牙源性肿瘤穿破骨皮质侵犯牙龈。外周性牙源性肿瘤预后普遍好于相应的骨内型肿瘤,但切除不彻底仍可复发,建议长期随访。     

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.     

Rare peripheral odontogenic tumors: report of 5 cases and comprehensive review of the literature

Peripheral odontogenic tumor (POT) is a rarely encountered lesion. We report 5 cases of POT including adenomatoid odontogenic tumor (AOT), keratocystic odontogenic tumor (KCOT), ameloblastic fibroma (AF), developing odontoma (DO), and calcifying cystic odontogenic tumor (CCOT), and also provide a review of relevant literature to define the tumor profile. Except for PCCOT with enough frequency (>100 cases), PAOT (n = 14), PKCOT (n = 15), PAF (n = 5), and PDO (n = 7) were scarce in the literature. As to the age distribution, PAOT, PAF, and PDO fell within the first 2 decades, whereas PKCOT arose in middle-aged adults. A marked female predominance was apparent in PAOT, PKCOT, and PAF. Approximately 90% of PAOT occurred in the maxilla. PAOT and PDO arose primarily in the incisor area, and PKCOT and PAF were typically located in permanent canine/premolar and deciduous molar regions, respectively. Although most PAOT and all PKCOT affected the buccal gingiva, PDO showed a strong predilection for the lingual aspect. With the exception of PKCOT, there was no propensity for recurrence in the above POT. At this time, it remains to be determined whether the biologic behavior of PKCOT is the same as for KCOT. In view of the reported cases, a true extraosseous origin of PAOT and PAF, for the most part, is challenging.     

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.     

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.     

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。     

Cystic variant of calcifying epithelial odontogenic tumor

The calcifying epithelial odontogenic tumor is a rare benign odontogenic neoplasm of the jaw. Clinically, calcifying epithelial odontogenic tumor manifests as an intraosseous lesion (central type) in the majority of cases (95%). Extraosseous or peripheral lesions account for less than 5% of cases. Calcifying epithelial odontogenic tumor can be associated with an impacted tooth and give a radiographic simulation of dentigerous cyst. Most calcifying epithelial odontogenic tumors are solid in nature, histopathologically, and might have few cyst-like spaces within them. However, a true cystic calcifying epithelial odontogenic tumor is a rare possibility. We describe a case of a true cystic variant of calcifying epithelial odontogenic tumor in a 30-year-old male, which to our knowledge, is only the second reported case.     

Revision der WHO-Klassifikation odontogener Tumoren von 1992

The WHO classification of odontogenic tumors (1992, OT) was revised. The following main changes were proposed: (1) OT are not only "related to" odontogenic tissues but are derived from these; (2) the stroma of the epithelial tumor group (1.1.1) is of a fibrous nature and does not contain any ectomesenchymal component; (3) subtypes of ameloblastomas have to be differentiated (intra-, extraosseous, desmoplastic, unicystic); (4) eponyms are no longer used in the revised classification; (5) the AOT is reclassified as an epithelial OT; (6) a neoplastic and non-neoplastic line of the ameloblastic fibroma and ameloblastic fibrodentinoma is proposed; (7) the calcifying ghost cell odontogenic tumor is included in the classification; (8) the simple and the WHO type of odontogenic fibroma are included in the classification; (9) the classification of malignant OT is adapted from Eversole (1999) with a few changes. In particular, ameloblastic carcinoma is differentiated from malignant (metastasizing) ameloblastoma; (10) the term carcinoma in intraosseous (peripheral) ameloblastoma is introduced. Also, the malignant epithelial odontogenic ghost cell tumor is termed calcifying ghost cell odontogenic carcinoma; (11) the clear cell odontogenic tumor is termed clear cell odontogenic carcinoma; (12) the so-called pseudocysts are termed "cavities" (aneurysmal bone cavity, simple bone cavity, lingual and buccal mandibular bone cavity, focal marrow-containing jaw cavity).     

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.     

The central (intraosseous) calcifying odontogenic cyst: an analysis of 215 cases

This study reviews and analyzes the clinical, radiographic, and histomorphologic features of the 215 cases of central calcifying odontogenic cyst (CCOC) reported in the literature. Based on the present information, a clinicopathologic classification of calcifying odontogenic cyst is proposed. The CCOC is also compared with its peripheral counterpart and the differences discussed.     

Peripheral calcifying odontogenic cyst

BACKGROUND: Calcifying odontogenic cyst (COC) is a rare lesion representing about 1% of jaw cysts. It may occur in a central (intraosseous) or peripheral (extraosseous) location. METHOD: A case of peripheral COC located on the gingiva, appearing as a painless, circumscribed, pink nodule has been reported. RESULTS: Peripheral, in contrast to central, COC tends to affect older patients. Peripheral COC is a less aggressive lesion than the central counterpart, and a simple excision biopsy is curative. CONCLUSION: The histological finding of a keratinized epithelium rich in ghost cells has helped in making the diagnosis.     

Peripheral ameloblastic fibro-odontoma or peripheral developing complex odontoma: report of a case

BACKGROUND. Peripheral (extraosseous) odontogenic tumors are rare. CASE REPORT. This report describes a case which illustrates the clinical and histopathological features of a lesion in an 8-year-old, healthy Caucasian girl that on purely morphological grounds would seem to be an ameloblastic fibro-odontoma, but may represent a case of a peripheral developing complex odontoma. CONCLUSION. Conservative surgical enucleation of the lesion was followed by unbcomplicated healing and no recurrence was seen.     

The peripheral odontogenic fibroma: an attempt at clarification

Two different lesions of the gingiva that have been referred to previously as peripheral odontogenic fibromas are discussed. The first of these is the rare extraosseous counterpart of the central odontogenic fibroma (WHO type)1 and is therefore referred to in this article as the peripheral odontogenic fibroma (WHO type). It is probably treated adequately by simple excision, but a study of its biologic behavior is lacking. The second lesion is reactive, is common, and has a marked tendency to recur. It has been known by numerous synonyms, including calcifying fibrous epulis and peripheral ossifying fibroma, as well as peripheral odontogenic fibroma. The term peripheral ossifying fibroma should be retained for this lesion to avoid confusion with the peripheral odontogenic fibroma (WHO type).     

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.     

骨外型牙源性钙化上皮瘤

骨外型牙源性钙化上皮瘤极为罕见,通过复习1966～2011年英文MEDLINE与1994～2011年中文CHKD中收录的文献,仅有37例骨外型牙源性钙化上皮瘤的个案报告。根据上述资料分析,发现该瘤具有以下临床特点,就诊年龄3～71岁,平均35.8岁;男13例,女19例,男女比例为1∶1.46;肿块直径0.5～4 cm,平均1.76 cm;好发部位主要是牙龈,累及下颌与上颌牙龈的比例为1∶1;组织学特征表现与骨内型牙源性钙化上皮瘤基本相同;复发率为5.4%。因该瘤具有浅表骨侵蚀能力,应行完整的肿瘤切除结合骨面刮治术。     

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.     

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.     

Peripheral odontogenic tumours--differential diagnosis in gingival lesions

Peripheral odontogenic tumours (POT) are rare benign focal overgrowths of the oral soft tissue, usually occurring in the gingiva. Between 1996-2000, 6 out of 406 excised gingival lesions were diagnosed as POT (1.5%). Tumours included peripheral odontogenic fibroma (2 patients), peripheral calcifying odontogenic cyst (2 patients), peripheral ameloblastoma (1 patient), and peripheral calcifying epithelial odontogenic tumour (1 patient). Review of the literature reveals that peripheral odontogenic fibroma and peripheral ameloblastoma were the most common POT. The purpose of this article was to analyse the clinical data of these tumours according to the presented cases and the literature review, to elucidate typical features of each tumour type and enhance easy identification.     

Peripheral odontogenic fibroma

Peripheral odontogenic fibroma (WHO type) is an uncommon lesion of the gingiva; 18 well-documented cases have been published. It is considered to be the extraosseous counterpart of the central odontogenic fibroma. Because of the paucity of reported cases, the full histomorphologic spectrum of this lesion has not yet been established. This article presents nine cases of peripheral odontogenic fibroma that illustrate the variety of its histopathologic findings. The connective tissue ranged from loose (almost myxomatous) to markedly cellular to relatively acellular and well-collagenized. Islands and/or strands of odontogenic epithelium were present in all lesions. Matrix of mineralized material was present in three cases, and juxtaepithelial hyalinization was seen in one case. To avoid the introduction of additional diagnostic terms, we suggest that all these lesions be considered a spectrum of the peripheral odontogenic fibroma (WHO type). We also suggest that the term WHO type be used to distinguish peripheral odontogenic fibromas from the peripheral ossifying fibroma with which they have often been confused.