Classification Of Odontogenic Tumors Research Articles

The utility of three-dimensional dynamic contrast-enhanced magnetic resonance imaging in delineating vessel-rich regions: a case report of an aneurysmal bone cyst of the mandible

Aneurysmal bone cysts (ABCs) are classified as bone-related lesions based on the 2005 World Health Organization histological classification of odontogenic tumors. Most ABCs are diagnosed using a combination of conventional radiography, computed tomography, magnetic resonance imaging (MRI), and digital subtraction angiography. ABCs should be differentiated from true cysts or other pseudocysts because their treatment is different. Additionally, unlike other cysts, ABCs pose a hemorrhagic risk in surgery; thus, preoperative evaluation of intralesional blood flow is required. Here we report a case of a mandibular ABC in a 39-year-old woman and focus on its dynamic contrast-enhanced MRI (DCE-MRI) features. On DCE-MRI, the lesion was divided into two areas according to the enhancement pattern: the blood-pooling and blood-flow areas. The series of DCE-MR images of the blood-pooling area showed marked enhancement of the margin, but no enhancement in the inner part of the cavity. Additionally, the time-signal intensity curve (TIC) demonstrated no change in the signal intensity (SI) until approximately 15 min after gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) administration. In contrast, the series of DCE-MR images of the blood-flow area exhibited marked enhancement in the cyst cavity in the early phase. The TIC showed a rapid increase in SI in the early phase, followed by a rapid decrease until 150 s, and finally a gradual decrease until approximately 15 min after Gd-DTPA administration. Thus, in the current patient, preoperative DCE-MRI clearly delineated the vessel-rich area within the lesion.

Is the Median Palatine Cyst a Distinct Entity?

T s h In 1992, the World Health Organization (WHO) published the second, revised edition of “Histological Typing of Odontogenic Tumours,” following the first edition published in 1971. It was the first authoritative and useful guide to the uneasy classification of odontogenic tumors. In this official position of the WHO, we can read the following: “Midline cysts of the maxilla and mandible, previously thought to be entities derived from epithelium entrapped during the fusion of embryonic facial processes. The existence of these cysts as entities derived in this way has been seriously questioned by embryologists and pathologists. It is now felt that those in the maxilla represent a posterior extension of a nasopalatine duct cyst in the case of a median palatine cyst and an anterior extension in the case of a median alveolar cyst. Occasionally, a cyst in the median alveolar position is a keratocyst. Cysts in the midline of the mandible may be radicular cysts, lateral periodontal cysts or odontogenic keratocysts.” Can we now assume that median palatine cysts (MPCs) are not a separate entity? Despite this, 3 cases of median maxillary cyst (or palatal median cyst) were reported in the literature after 1992. In the most recent case, published by Manzon et al in 2009, the authors stated that MPC s an uncommon nonodontogenic cyst, because it

Clear-Cell Odontogenic Carcinoma: A New Case and Long-Term Follow-Up of an Old Case, and Review of the Literature

Clear-cell odontogenic carcinoma (CCOC) is a rare neoplasm of the jaws, as first described by Hansen et al in 1985.1 Located in the mandible and maxilla, its histologic appearance suggests an odontogenic origin. The CCOC, formerly termed clear-cell odontogenic tumor, was included in the World Health Organization (WHO) classification of odontogenic tumors in 1992.2 This tumor was defined as a benign neoplasm with a capacity for locally invasive growth, and was considered more aggressive than 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.

International collaborative study on ghost cell odontogenic tumours: calcifying cystic odontogenic tumour, dentinogenic ghost cell tumour and ghost cell odontogenic carcinoma

Calcifying odontogenic cyst was described first by Gorlin et al. in 1962; since then several hundreds of cases had been reported. In 1981, Praetorius et al. proposed a widely used classification. Afterwards, several authors proposed different classifications and discussed its neoplastic potential. The 2005 WHO Classification of Odontogenic Tumours re-named this entity as calcifying cystic odontogenic tumour (CCOT) and defined the clinico-pathological features of the ghost cell odontogenic tumours, the CCOT, the dentinogenic ghost cell tumour (DGCT) and the ghost cell odontogenic carcinoma (GCOC). The aim of this paper was to review the clinical-pathological features of 122 CCOT, DGCT and GCOC cases retrieved from the files of the oral pathology laboratories from 14 institutions in Mexico, South Africa, Denmark, the USA, Brazil, Guatemala and Peru. It attempts to clarify and to group the clinico-pathological features of the analysed cases and to propose an objective, comprehensive and useful classification under the 2005 WHO classification guidelines. CCOT cases were divided into four sub-types: (i) simple cystic; (ii) odontoma associated; (iii) ameloblastomatous proliferating; and (iv) CCOT associated with benign odontogenic tumours other than odontomas. DGCT was separated into a central aggressive DGCT and a peripheral non-aggressive counterpart. For GCOC, three variants were identified. The first reported cases of a recurrent peripheral CCOT and a multiple synchronous, CCOT are included. Our results suggest that ghost cell odontogenic tumours comprise a heterogeneous group of neoplasms which need further studies to define more precisely their biological behaviour.

角化嚢胞性歯原性腫瘍の臨床的検討

The odontogenic keratocyst (OKC) was originally classified as a developmental cyst, and OKCs were histologically divided into orthokeratotic (O-OKCs) and parakeratotic type (P-OKCs). Clinical features differ between O-OKCs and P-OKCs. P-OKCs have a tendency to recur after surgical treatment, as compared with OOKCs. According to the revised histopathological classification of odontogenic tumors by the World Health Organization (2005), the term keratocystic odontogenic tumor (KCOT) was adopted for P-OKCs.In this retrospective study, we examined 186 KCOTs treated at the Maxillofacial Surgery, Tokyo Medical and Dental University Hospital from 1981 through 2005. The patients ranged in age from 7 to 85 years (mean, 32.7) and consisted of 93 males and 93 females. The most frequently involved regions were the mandibular molar region and ramus. The majority of KCOTs in the maxillary region were treated by enucleation and primary closure. The majority of KCOTs in the mandibular region were enucleated, and the wound was left open. Marginal resection was performed in the 4 patients with large lesions arising in the mandible. Recurrences occurred in 19 of 120 lesions (15.8 %) in patients who were followed for more than a year. The recurrences were found at the margins of the primary lesion in contact with the roots of teeth or at the upper margins of the mandibular ramus.Clinicians should consider aggressive treatment for KCOT because the recurrence rate of P-OKCs is higher than that of the other cyst types, such as O-OKCs, dentigerous cysts, and primordial cysts that were non-keratinized, and slightly keratinized stratified squamous epithelium. Thus, more aggressive treatment is needed for KCOTs as compared with other cystic lesions. However, it is difficult to make a precise diagnosis preoperatively on the basis of clinical features and X-ray imaging. Therefore, preoperative biopsy is necessary for selecting the appropriate treatment for patients with cystic lesions.

Diagnosis and Management of Odontogenic Myxoma in a Dog

A three-year-old Jack Russell terrier dog was presented with a large gingival mass of the right mandible extending from the fourth premolar to the first molar teeth. Radiographic examination of the expansile mass revealed moth-eaten, honeycomb-like lyses of the mandible and extended into the mandibular alveolar canal based on computed tomography. The histopathological diagnosis of the biopsy was odontogenic fibromyxoma. Mandibulectomy with resection of the associated soft tissues was performed. Surgical management was curative with no clinical signs of disease 2-years after treatment. These neoplasms are slow growing, locally destructive tumors of odontogenic origin that have been described in the jaw of only one dog. In this paper, the clinico-radiological and pathologic features, diagnostic modalities as well as the factors that might influence treatment outcome of odontogenic myxomas are discussed. These odontogenic tumors are currently excluded from the WHO classification of odontogenic tumors in domestic animals and inclusion in future classifications systems is proposed.

Dentinogenic Ghost Cell Tumors

Calcifying odontogenic cyst (COC) was first described by Gorlin et al in 1962 1 Gorlin R.J. Pindborg J.J. Clausen F.P. et al. The calcifying odontogenic cyst: A possible analogue of the cutaneous calcifying epithelioma of Malherbe. Oral Surg Oral Med Oral Pathol. 1962; 15: 1235 Abstract Full Text PDF PubMed Scopus (267) Google Scholar and defined by WHO 2 Kamijo R. Miyaoka K. Tachikawa T. et al. Odontogenic ghost cell carcinoma: Report of a case. J Oral Maxillofac Surg. 1999; 57: 1266 Abstract Full Text PDF PubMed Scopus (14) Google Scholar in 1971 as “a cystic lesion in which the epithelial lining shows a well-defined basal layer of columnar cells, an overlying layer that is often many cells thick and that may resemble stellate reticulum, and masses of ghost epithelial cells that may be in the epithelial cyst lining or in the fibrous capsule.” Calcifying odontogenic cyst has the features of a cyst primarily, but it also has some characteristics of a solid neoplasm. The solid variant of COC was called calcifying ghost cell odontogenic tumor formerly. The nomenclature of this tumor was changed to dentinogenic ghost cell tumor (DGCT) at 2005 World Health Organization (WHO) histologic classification of odontogenic tumors. 3 Barnes L. Eveson J. Reichart P. et al. WHO classification of tumors: Pathology and genetics of tumors of the head and neck. Oxford University Press, Lyon, France2005 Google Scholar On rare occasions, the lesion may even transform into carcinoma. 4 Lin C.C. Chen C.H. Lin L.M. et al. Calcifying odontogenic cyst with ameloblastic fibroma: Report of three cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2004; 98: 451 Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar This report describes a case of DGCT that occurred in the maxilla of a 20-year-old female.

Ameloblastomas: a regional Latin‐American multicentric study

To classify 163 ameloblastoma cases according to the new WHO Classification of Odontogenic Tumours (2005) and analyse their clinical and microscopic features. We studied the clinico-pathological features of 163 ameloblastoma cases from nine regional Latin-American institutions from Mexico and Guatemala. Ameloblastomas comprised 22.7% of all odontogenic tumours. The mean age was 41.4 years for solid ameloblastoma (SA) and 26.3 years for unicystic ameloblastoma (UA) (P < 0.001) and both sexes were almost equally affected. The mandible was mainly affected for both UA and SA. The mean size was 6.2 cm for SA and 6.3 cm for UA cases. The recurrence rate was 21.7% for SA and 12.6% for UA. UA was twice as more frequent than the solid variant. In this study we found that UA was frequently misdiagnosed as SA; however, there are enough clinical and microscopic features that allow for an accurate differentiation between both types of ameloblastoma that should be recognized for surgical and prognostic purposes. In this study, SA was not found in patients younger than 20 years, UA had a constant myxoid stroma while mature connective tissue was more frequently associated with the solid type.

Clinico-pathological Analysis of Odontogenic Tumours According to the Revised WHO (2005) Histopathological Classification in Japanese

The revised histopathological classification of odontogenic tumours by the World Health Organization (WHO) was published in 2005 in and Genetics of the Head and Neck Tumours. This study sought to determine the relative frequency of odontogenic tumours in the Japanese population and to compare these data with previous classifications of odontogenic tumours.289 patients with odontogenic tumours diagnosed at the Department of Oral Pathology in Kyushu Dental College, Japan during a 20-year period from 1985 to 2004 were reviewed and reclassified according to the revised histopathological classification of odontogenic tumours by WHO published in 2005. Clinical data, including frequency, age, gender, and anatomical location, were also analyzed and collected.Odontogenic tumours accounted for 4.1% of all the oral and maxillofacial lesions (n=289).Of these, 289 patients (99.31%) had benign tumours and 2 (0.69%) had malignant tumours. The most frequent of the benign tumours were keratocystic odontogenic tumours (n=86), followed by ameloblastomas (n=81) and odontomas (n=79).These tumours constituted 84.43% of the all the odontogenic tumours. The mean age for benign odontogenic tumours was 32.36 ±19.83 years and for malignant tumours was 30 years, with the majority 189 (65.40%) of odontogenic tumours occurring in the second and the third molar region of the mandible, especially the posterior region 139 (48.10%). The male:female ratio for the all odontogenic tumours was 1:0.91.Conclusions:Keratocystic odontogenic tumours therefore tend to show a higher frequency of occurrence among odontogenic tumours than ameloblastoma, according to this new classification.

Desmoplastic ameloblastoma in Indians: Report of five cases and review of literature

In the recent World Health Organization classification of odontogenic tumours, desmoplastic ameloblastoma has been characterized as a variant of ameloblastoma, with specific clinical, radiographical, and histological features. Till date, 145 cases have been reported in Japanese, Chinese, Malaysian, Western, and African populations, with very few cases described in Indians. Here, we report five cases in the Indian population. The male to female ratio was 3:2. The mean age at diagnosis was 33.2 years. Four of the tumours were located in the maxilla, in the anterior premolar region. The lone mandibular tumour was located anteriorly, crossing the midline. Three of the tumours had a mixed radiologic appearance with poorly defined borders. Unilocular change was seen in one of them. Two tumours presented as unilocular radiolucencies with specks of radiopacities and well-circumscribed borders. Histologically, irregular odontogenic islands, with a stretched-out 'kite-tail' appearance, were seen in a dense desmoplastic stroma. The peripheral layer of the epithelial islands was made up of flattened cells and the inner core was made up of spindle-shaped and, in some instances, squamous-shaped cells. In two cases, odontogenic epithelium in the form of follicles, typical of solid/multicystic ameloblastoma, was seen and these were typed as 'hybrid' variants. All the cases were treated by resection.

歯牙腫を伴い上顎洞に充満した石灰化嚢胞性歯原性腫瘍の１例

Calcifying cystic odontogenic tumors classified as a tymor by the WHO International Classification of Odontogenic Tumors and Allied Lesions in 2005, are rare.We report the case of a large calcifying cystic odontogenic tumor that arose in the maxillary sinus of a 27-yearold woman in association with odontoma and an impacted tooth.We examined the size of the lesion by dental cone beam computed tomography. It was the largest lesion to be reported in Japan, measuring 62.2×53.5×52.6mm. Dental cone beam computed tomography was very useful for accuratetly measuring the size of this tumor.

Odontogenic tumours: a retrospective study of 1642 cases in a Chinese population

A total of 1642 odontogenic tumour cases retrieved from the files of the College of Stomatology, Sichuan University, China were retrospectively analyzed for gender, age, tumour site and relative frequency of various types, and the data compared with that of previous reports. The final diagnosis in each case was based on the WHO 2005 histopathological classification of odontogenic tumours. Of these tumours 1592 (97.0%) were benign and 50 (3.0%) were malignant. Ameloblastoma (40.3%) was the most frequent type, followed by keratocystic odontogenic tumour (35.8%), odontoma (4.7%) and odontogenic myxoma (4.6%). The mean age of the patients was 32.1, with a wide range (3–84 years). The male–female ratio and maxilla–mandible ratio were 1.4:1 and 1:4.0, respectively. Ameloblastoma and keratocystic odontogenic tumours, important indications of extensive surgical procedures, are not considered rare in this Chinese population, whereas odontoma is uncommon.

Expression of nuclear factor-kappaB, Ki-67 and matrix metalloproteinase-9 in calcifying odontogenic cyst

To evaluate the expression of nuclear factor-kappaB (NF-kappaB), Ki-67 and matrix metalloproteinase-9 (MMP-9) in calcifying odontogenic cyst (COC), in order to investigate the proliferation and invasion of COC. Twenty-six cases of COC were classified into calcifying cystic odontogenic tumor (CCOT), dentinogenic ghost cell tumor (DGCT) and ghost cell odontogenic carcinoma (GCOC) based on the WHO classification of odontogenic tumors in 2005. The specimens of COC and 10 classic ameloblastoma (AB) were examined immunohistochemically to determine the expression of NF-kappaB p65, Ki-67 and MMP-9. NF-kappaB was mainly detected in the cytoplasm of most tumor cells, but was only detected in the nucleus of few tumor cells (rate of nuclear staining < 1%). The expression of Ki-67 was significantly higher in GCOC than in CCOT (P < 0.001), DGCT (P < 0.05) and AB (P < 0.005). MMP-9 was detected both in tumor cells and stromal cells. GCOC showed significantly higher percentage of MMP-9 positive cases in stromal cells than CCOT, DGCT and AB (P < 0.05). NF-kappaB may minimally affect the progression and invasion of COC. GCOC shows significantly higher proliferative activity and aggressiveness than CCOT and DGCT. MMP-9 in stroma may play a key role in the invasion of GCOC.

Classification of odontogenic tumours. A historical review

Using the term odontome for any tumour arising from the dental formative tissues, Broca suggested a classification of odontogenic tumours (OTs) in 1869. From 1888 to 1914, Bland-Sutton and Gabell, James and Payne modified tumour terminology, while maintaining Broca's odontome concept. Thoma and Goldman's classification (1946) divided the OTs into tumours of ectodermal, mesodermal and mixed origin and abolished the general term odontome. The Pindborg and Clausen classification (1958) based on the idea that the reciprocal epithelial-mesenchymal tissue interactions were also operating in the pathogenesis of OTs. In 1966, WHO established a Collaborating Centre for the Histological Classification of Odontogenic Tumours and Allied Lesions (including jaw cysts) headed by Dr Jens Pindborg. In 1971, the first authoritative WHO guide to the classification of OTs and cysts appeared followed in 1992 by a second edition. In 2002, Philipsen and Reichart produced a revision of the 1992-edition and in 2003, the editors of the WHO Blue Book series: 'WHO Classification of Tumours' decided to produce a volume on the Head and Neck Tumours including a chapter on Odontogenic Tumours and Bone Related Lesions. In July of 2005 this volume was published by IARC, Lyon.

Ectodermal odontogenic tumours: analysis of 197 Nigerian cases

This article presents a clinico-pathologic analysis of 197 cases of ectodermal odontogenic tumours archieved 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 31.0±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.

Inflammatory paradental cyst. Report of 6 cases

The inflammatory paradental cyst has been described as an entity in the WHO classification of odontogenic tumors and cysts (1992). It is mainly located at mandibular molars, in particular third molars of the lower jaw. Radiologically, involved molars show a circumscribed, mostly half-moon shaped translucency distal or distobuccal to the involved tooth. Patients frequently report episodes of infection (pericoronitis). The histological findings are identical to those of inflammatory radicular cysts. The inflammatory paradental cyst has been described infrequently in the international literature. There are no reports available in German. The aim of the present study was to present six of our own cases of inflammatory paradental cysts. Five men and one woman with an average age of 29.5 years were affected. In two cases paradental cysts occurred bilaterally. Three patients reported recurrent previous infections (pericoronitis). Radiologically, the typical translucency with clear demarcation distal to the third molars was observed. All of the third molars were vertically retained. Histologically, the inflammatory paradental cysts showed features identical to those of radicular cysts. The inflammatory paradental cyst is a clear indication for osteotomy of lower wisdom teeth. Postoperative complications or recurrences of the inflammatory paradental cysts have not been described. A correct clinical, radiological, and histopathological diagnosis of paradental cysts is mandatory, and more reports are needed in order to compile more information about relative frequency and pathogenesis of this cyst variant.

Revision of the 1992 edition of the WHO histological typing of odontogenic tumors. A suggestion

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).

顎骨に生じた開花性セメント質骨異形成症の臨床病理学的検討

Florid cemento-osseous dysplasia (FCOD) was newly added to the World Health Organization classification of odontogenic tumors in 1992. We reviewed 7 cases of FCOD treated between 1994 and 2001. All patients were women. The mean age was 69.4 years, with a range of 60 to 89 years. FCOD lesions often occurred in the posterior part of the mandible. The lesions were removed under general anesthesia. Histopathological examination of the surgical specimens showed that FCOD consisted of many lobulated masses resembling cementum. FCOD lesions were often surrounded by loose, fibrous connective tissue containing many small cementicle-like masses.Computed tomography and 99mTc-MDP scintigraphy were useful for both diagnosis and management of FCOD.

Odontoameloblastoma. Clinico-pathologic study of three cases and critical review of the literature

The odontoameloblastoma (OA), is an infrequent neoplasm. To date, there are less than 50 cases reported as OA or ameloblastic odontoma in the English dental literature, but only 14 (including three of our own material), fulfill the histological criteria of the current WHO histological classification of odontogenic tumours. Nine occurred in men and five in women (male to female ratio 1.8:1). Age ranged from 2 to 50 years (mean 20.2 years), and nine cases (64.2%) were diagnosed during the first two decades. Maxilla and mandible were equally involved, and most cases occurred posterior to the canines (71.4%). Follow-up ranged from 6 months to 8 years (mean: 25.5 months). Of the 12 cases with informed follow-up, two recurred once (at 24 and 18 months, respectively), and one case had two documented recurrences, at 6 and 49 months. Although OA tends to occur at an earlier age than conventional ameloblastoma, it has practically the same potential to produce bone expansion, root resorption and recurrence. For these reasons OA should be treated in a similar fashion, with wide surgical excision and close follow-up for at least 5 years.