Ameloblastic fibroma and related lesions: current pathologic concept

Maxillary Cystic Ameloblastic Fibroma in a Dalmatian Mix

A 6-month-old intact male Dalmatian mix puppy was presented for the evaluation of left maxillary swelling due to a suspected cyst and an unerupted left maxillary canine tooth. Removal of the unerupted left maxillary canine tooth (204) and enucleation of the cyst was performed, followed by histological analysis, which identified the maxillary swelling to be a cystic ameloblastic fibroma. Ameloblastic fibromas are rare in companion animals, and to the best of the authors' knowledge, this is the first cystic variant reported in dogs. The clinical, radiographic, cone beam computed tomography, and histological findings of this case are discussed and compared with the findings of previously documented human and domestic animal cases.

Central Granular Cell Odontogenic Tumor of the Mandible: An Uncommon Presentation

Central granular cell odontogenic tumor (CGCOT) is a rare, benign odontogenic tumor resulting from the jaw bone, especially the mandible or maxilla. It affects women of middle age and usually occurs as a painless swelling of the mandibular premolar-molar area. CGCOT is characterized by the presence of granular cells, which are large, eosinophilic, granular-looking cells found in the tumor tissue. We report an unusual CGCOT in a 38-year-old male patient's mandibular region. We also describe the clinical, radiological, and pathological characteristics along with the immunohistochemical investigation of the tumor.

Pediatric Odontogenic Tumors

Odontogenic tumors are rare tumors of the jaws that arise from remnants of the tooth forming apparatus. Some odontogenic tumors demonstrate strong predilection for pediatric patients including the unicystic ameloblastoma, adenomatoid odontogenic tumor, ameloblastic fibroma, ameloblastic fibro-odontoma, odontoma, and primordial odontogenic tumor. In this review, we discuss the clinical, radiographic, histopathologic, and molecular characteristics of select odontogenic tumors that demonstrate pediatric predilection and review management.

A Systematic Review of the Granular Cell Odontogenic Fibroma and Report of a New Case

BACKGROUND

Granular Cell Odontogenic Fibroma (GCOF) is a rare odontogenic neoplasm reported over time with different names. The purpose of this study is to review all available data on the GCOF in the scientific literature, with a summary of all reported cases and a report of a new case.

METHODS

This review was conducted following the PRISMA guidelines. An electronic search was performed up to November 2022.

RESULTS

Thirty-nine studies reporting fifty-three cases were included. GCOF is a rare neoplasm among the odontogenic tumors, with a higher prevalence in women of the middle-aged and white population. This lesion occurs mostly on the posterior region of the mandible. Furthermore, based on clinical, radiographic, and histopathologic features, conservative treatment was the most reported choice with recurrence reported in two cases.

CONCLUSION

GCOF remains controversial due to the still unsolved histogenesis.

Analysis of the 100 most cited articles on ameloblastoma

OBJECTIVES

An increasing number of articles are published each year. The aim of this is to provide a list of the 100 most cited articles on the subject of ameloblastoma.

METHODS

A bibliographic search was performed on Google Scholar (GS), Microsoft Academic (MA), and Dimensions for ameloblastoma. A ranking was created in order of citation density. Graphical representations of keywords and authorship were created with VOSviewer. Statistical analysis was performed and only results with a 95% confidence interval were considered significant.

RESULTS

A helpful list of top 100 articles was developed to help professionals in a variety of ways. Some curiosities are discussed about this scientometric analysis in ameloblastoma articles.

CONCLUSIONS

A useful list of the top 100 most cited articles on ameloblastoma has been provided. Bibliometric and altmetric analysis using Google Scholar, Microsoft Academic, and Dimensions is a free and excellent tool, not only as a citation manager but also as a study reference.

Ameloblastic fibroma: A case report

Ameloblastic fibroma is a rare mixed odontogenic benign tumor that can occur in either mandible or maxilla but mostly it is found in posterior region of mandible. It can present either peripherally or centrally with a majority of the cases predominantly occurring in first two decades of life and mostly affects male patients. It is characterized by epithelial islands and cords submerged in ectomesenchyme that bear resemblance to the dental papilla and enamel organ but without actual hard tissue formation. Ameloblastic fibroma is a rare odontogenic tumor consisting of neoplastic epithelial and mesenchymal tissues. Recent reports have suggested that this lesion has the potential for high recurrence (18%) and greater chances of recurrent Ameloblastic fibroma transforming into Ameloblastic fibrosarcoma (45%). A 34-year-old male patient presented with pain and swelling in right mandibular posterior region. Intraorally expansion of buccal cortical plate with tenderness over swelling was present. Extraoral examination revealed facial asymmetry on right side. In view of imaging and clinical findings, provisional diagnosis of Odontogenic Keratocyst or Recurrent Ameloblastoma was considered. After obtaining informed consent and general systemic evaluation, the lesion was enucleated under general anesthesia and biopsied which confirmed the diagnosis of Ameloblastic fibroma. Ameloblastic fibroma is a mixed odontogenic tumor composed of odontogenic ectomesenchyme resembling dental papilla with epithelial strands and nests similar to the dental lamina and enamel organ, but with no dental hard tissue formation. Odontogenic tumors, Ameloblasts, Ameloblastoma, Jaw neoplasm.

Expression of SOX2 and OCT4 in odontogenic cysts and tumors

Background

Aberrant expression of stem cell markers has been observed in several types of neoplasms. This trait attributes to the acquired stem-like property of tumor cells and can impact patient prognosis. The objective of this study was to comparatively analyze the expression and significance of SOX2 and OCT4 in various types of odontogenic cysts and tumors.

Methods

Fifty-five cases of odontogenic cysts and tumors, including 15 ameloblastomas (AM), 5 adenomatoid odontogenic tumors (AOT), 5 ameloblastic fibromas (AF), 5 calcifying odontogenic cysts (COC), 10 dentigerous cysts (DC) and 15 odontogenic keratocysts (OKC) were investigated for the expression of SOX2 and OCT4 immunohistochemically.

Results

Most OKCs (86.7 %) and all AFs expressed SOX2 in more than 50 % of epithelial cells. Its immunoreactivity was moderate-to-strong in all epithelial cell types in both lesions. In contrast, SOX2 expression was undetectable in AOTs and limited to the ameloblast-like cells in a minority of AM and COC cases. Most DCs showed positive staining in less than 25 % of cystic epithelium. Significantly greater SOX2 expression was noted in OKC compared with DC or AM, and in AF compared with COC or AOT. OCT4 rarely expressed in odontogenic lesions with the immunoreactivity being mild and present exclusively in OKCs.

Conclusions

SOX2 is differentially expressed in odontogenic cysts and tumors. This could be related to their diverse cells of origin or stages of histogenesis. The overexpression of SOX2 and OCT4 in OKC indicates the acquired stem-like property. Future studies should investigate whether the overexpression of OCT4 and SOX2 contributes to the aggressive behaviors of the tumors.

Early presentation in ameloblastic fibroma

Ameloblastic fibroma are rare mixed tumors composed by both epithelial and mesenchymal tissues. They mostly affect the posterior mandibular sector in young adults. Here we report an atypical case affecting a very young patient in an unusual localization. We describe the management of the case and discuss the origin of this little know lesion.

Highly Proliferative Ameloblastic Fibroma: A Rare Entity

Ameloblastic fibroma (AF) is a rare odontogenic neoplasm which is commonly seen in the second decade of life. It is seen most frequently in the mandibular posterior region. AF shows clinical and radiographic resemblance with other commonly occurring odontogenic cyst and tumors. Histopathologically, it shows great resemblance with primitive dental papilla. Immunohistochemistry helps in understanding the nature and proliferative potential of tumor and helps in proper treatment planning. Large lesions and recurrent lesions are treated with segmental resection which can often lead to morbidity, especially in young patients if not managed properly. Herein, we present a case of a large AF in the posterior mandible region in a 21-year-old female patient with significant expansion and erosion of cortical plates and lower border of the mandible with a high Ki67 proliferative index (20%) which was surgically treated by segmental resection and immediate reconstruction by autogenous iliac graft.

Primordial odontogenic tumor: a case report and literature review

Background

A primordial odontogenic tumor (POT) is a rare, benign, mixed epithelial and mesenchymal odontogenic tumor that has been included as a new entity in the latest World Health Organization (WHO) classification (2017). POT consists of dental papilla-like myxoid connective tissue covered with a delicate membrane of ameloblastic epithelium. Only 15 cases have been documented worldwide, and here, we report the sixteenth case and the first one of South Korea.

Case presentation

An asymptomatic lesion was discovered as an incidental radiographic finding in a 10-year-old boy. The patient had no complaints about the lesion. Cone-beam computerized tomograms revealed a round cavity with a defined cortical border measuring approximately 5 × 5 × 5 mm in size. The lesion was a POT. The patient was treated with enucleation. The tumor showed no recurrence for one year.

Conclusion

This is the first report of POT in South Korea using the novel diagnosis of POT after it was recognized and defined in the latest WHO classification. This novel diagnosis will be useful for pathologists and clinicians in diagnosing and differentiating this new and rare disease from other odontogenic tumors.

Ameloblastic Fibrosarcoma: A Case Report and Literature Review

Here is described a case of ameloblastic fibrosarcoma (AFS) affecting the posterior mandible of a woman who was treated surgically and recovered without signs of recurrence or metastasis after 12 years of follow-up. Tumor sections were immunostained for cell cycle, epithelial and mesenchymal markers. Immunohistochemical analysis evidenced high Ki-67 positivity in stromal cells (mean of 20.9 cells/High power field). Epithelial cells displayed strong positivity for p53, p63 and cytokeratin 19. In addition to the case report, a systematic review of current knowledge is presented on the AFS's clinical-demographic features and prognostic factors. Based on the review, 88/99 cases were diagnosed as AFS, 9/99 as ameloblastic fibro-odontosarcoma and 2/99 as ameloblastic fibrodentinosarcoma. All these lesions displayed very similar clinical-demographic and prognostic features. Moreover, the review provided evidence that first treatment, regional metastasis, distant metastasis and local recurrence were significant prognostic values for malignant odontogenic mesenchymal lesions. Based on the findings, segregation among ameloblastic fibrosarcoma, ameloblastic fibrodentinosarcoma and ameloblastic fibro-odontosarcoma seems illogical, considering all these lesions have similar predilections and outcomes.

Odontogenic Cysts and Neoplasms

This article reviews a myriad of common and uncommon odontogenic cysts and tumors. The clinical presentation, gross and microscopic features, differential diagnosis, prognosis, and diagnostic pitfalls are addressed for inflammatory cysts (periapical cyst, mandibular infected buccal cyst/paradental cyst), developmental cysts (dentigerous, lateral periodontal, glandular odontogenic, orthokeratinized odontogenic cyst), benign tumors (keratocystic odontogenic tumor, ameloblastoma, adenomatoid odontogenic tumor, calcifying epithelial odontogenic tumor, ameloblastic fibroma and fibroodontoma, odontoma, squamous odontogenic tumor, calcifying cystic odontogenic tumor, primordial odontogenic tumor, central odontogenic fibroma, and odontogenic myxomas), and malignant tumors (clear cell odontogenic carcinoma, ameloblastic carcinoma, ameloblastic fibrosarcoma).

Ameloblastic Fibrodentinoma: Report of a Case in an Infant

Ameloblastic fibrodentinoma (AFD) is a debatable neoplasm with respect to its clinical, biological and histopathological diagnosis. The clinical and radiological presentation may mimic ameloblastic fibro odontoma, odontoma, ameloblastic fibroma and cemento-ossifying fibroma. We report an interesting case of AFD occurring in canine region of mandible in a one-year-old infant. From a review of English language literature, to the best of our knowledge this is the first case occurring in an infant. The purpose of this case report is to create awareness among the clinicians to make the best possible management of this controversial pathologic entity.

Ameloblastic fibrodentinoma presenting as a false gingival enlargement in the maxillary anterior region

Ameloblastic fibrodentinoma is a rare benign mixed odontogenic neoplasm usually occurring in the first two decades of life. It is more common in males and the most common site of occurrence is in the mandibular premolar molar area. This report presents a case of ameloblastic fibrodentinoma in a 12-year-old boy in the maxillary anterior region, a less common site for the occurrence of ameloblastic fibrodentinoma. A 12-year-old boy presented with a midline diastema in 11 and 21 region and a swelling in the palatal aspect of 11 and 12. Intraoral periapical radiograph showed the presence of rarefaction of bone on the mesial aspect of the cervical and middle third of the root of 11. Excision biopsy was done. The specimen was processed and stained with hematoxylin and eosin. Microscopic examination showed islands, chords and strands of odontogenic epithelium in a primitive ectomesenchyme resembling dental papilla. The odontogenic epithelium exhibited peripheral ameloblast-like and central stellate reticulum-like cells. The presence of dentinoid material was seen adjacent to the odontogenic epithelium in some foci. The lesion was diagnosed as ameloblastic fibrodentinoma.

Ameloblastic fibroma in an alpine chamois (Rupicapra rupicapra)

Spontaneous odontogenic tumors are neoplasms characterized by a mixed odontogenic ectomesenchymal and odontogenic epithelial origin; they are rare in both humans and animals. A 3-year-old male Alpine Chamois (Rupicapra rupicapra) was found dead in north-west Italy, and was referred for the necropsy to the Department of Veterinary Sciences of the University of Turin (Italy). At the external examination a 10 × 8 cm, exophytic, red-pink, smooth, firm and ulcerated mass was observed on the inferior lip. Histologically the tumor was characterized by spindle shaped cells arranged in bundles in an abundant hyaline matrix. Multifocal and rare chords of odontogenic epithelium mixed with rare melanocytes that penetrate the neoplasia were visible. Immunohistochemistry showed a clear cytokeratin positivity of epithelial clusters. Macroscopical, histological and immunohistochemical findings were consistent with a diagnosis of locally infiltrative ameloblastic fibroma. To our best knowledge, this is the first report of this tumor in a wild ungulate and in Alpine Chamois.

Ameloblastic fibroma of the maxilla with bilateral presentation: report of a rare case with review of the literature

Ameloblastic fibroma (AF) is an uncommon benign odontogenic tumour, with both epithelial and mesenchymal neoplastic proliferation. It occurs most frequently in the posterior region of the mandible, while its occurrence in the maxilla is extremely rare. They are usually encountered in children, emphasizing it as an important diagnostic consideration. Herein, we report the first case of a bilateral maxillary ameloblastic fibroma in a 2-year-old female child patient who presented with a chief complaint of swelling in the right mid facial region.

Molecular and genetic aspects of odontogenic lesions

In this article we outline the molecular findings of select odontogenic tumors. In each section, we briefly review selected the clinicoradiographic, histologic, immunologic features, focusing on the molecular findings and their applications in practice. The understanding of molecular pathobiology at various other organ sites has developed quite rapidly in recent years, however much remains unknown about the genetic profile of odontogenic tumors. Improved understanding of mutations in odontogenic tumors may clarify classification schema and elucidate targets for novel therapies. Molecular testing will no doubt improve our understanding of odontogenic tumor pathogenesis and will likely be, someday, an important component of routine clinical practice and its role will only increase in the coming years.

Ameloblastic fibro-odontoma

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Incidental finding of a radiopaque mass in right posterior maxilla.

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A 10-year-old child.

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Radiopaque mass found to be associated with unerupted upper right second molar.

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Excisional biopsy shows the lesion to be a rare case of ameloblastic fibro-odontoma which is a mixed odontogenic tumour.

INTRODUCTION

Ameloblastic fibro-odontoma (AFO) is a quite rare, mixed odontogenic tumour generally seen in the early stages of life. Frequent signs of this tumour are asymptomatic swelling, delayed tooth eruption and mixed radiological appearance within well-defined borders. Management of the lesion includes enucleation of the tumour and long-term follow-up.

PRESENTATION OF CASE

A 10-year-old girl was referred to our oral and maxillofacial surgery clinic with an incidental radiological finding of radiopaque mass in the posterior region of maxilla. OPG showed unerupted tooth bud of upper right second molar and was being prevented from eruption by the odontome. Under general anaesthesia, the lesion was enucleated and the permanent right upper second molar tooth bud removed.

DISCUSSION

Mixed odontogenic tumours are a group of rare and interesting lesions which can mislead the clinician to variety of differential diagnosis. Adequate clinical and radiological investigations, proper surgical excison, accurate histopathological diagnosis, and long term follow up will ensure the right treatment plan for the patient.

CONCLUSION

The possibility of a mixed rare tumour should be kept in mind by the clinician where they deal with the swellings of posterior maxilla in children. Histological assessment revealed a final diagnosis of ameloblastic fibro-odontoma.

Odontomas and supernumerary teeth: is there a common origin?

The aim of the present work is to analyze all scientific evidence to verify whether similarities supporting a unified explanation for odontomas and supernumerary teeth exist. A literature search was first conducted for epidemiologic studies indexed by PubMed, to verify their worldwide incidence. The analysis of the literature data shows some interesting similarities between odontomas and supernumerary teeth concerning their topographic distribution and pathologic manifestations. There is also some indication of common genetic and immuno-histochemical factors. Although from a nosological point of view, odontomas and supernumeraries are classified as distinct entities, they seem to be the expression of the same pathologic process, either malformative or hamartomatous.

Primordial odontogenic tumour: clinicopathological analysis of six cases of a previously undescribed entity

AIM

To describe the clinicopathological and immuno-histochemical features of six tumours that do not fulfil the criteria of any of the currently classified odontogenic tumours.

METHODS AND RESULTS

The patients were three males and three females, whose ages ranged from 3 years to 18 years (mean, 11.05 years). In all cases there were well-defined radiolucencies associated with unerupted teeth apparently showing a pericoronal relationship. Microscopically, all tumours were composed of variably cellular loose fibrous tissue with areas similar to dental papilla, entirely surrounded by cuboidal to columnar epithelium resembling the internal epithelium of the enamel organ. Mesenchymal tissue was positive only for vimentin, and Ki67 expression was very low (<2%). The epithelium was positive for CK AE1/AE3, CK5, CK14, and CK19, but negative for CK18 and CK20. All cases showed clear demarcation from the surrounding bone, and were surgically removed, with no recurrences after follow-up ranging from 6 months to 20 years.

CONCLUSIONS

These findings differ from those observed in other odontogenic lesions, such as ameloblastic fibroma, odontogenic myxoma, odontogenic fibroma, and hyperplastic dental follicles. The term primordial odontogenic tumour is proposed to describe this novel lesion.

A peripheral ameloblastic fibro-odontoma in a 3-year-old girl: case report, immunohistochemical analysis, and literature review

Ameloblastic fibro-odontoma (AFO) predominantly occurs in the jaw bones of children and young adults. Extraosseous AFO is extremely rare. We describe a peripheral ameloblastic fibro-odontoma in the maxillary gingiva of a 3-year-old girl. The clinical appearance resembled fiery red reactive gingival lesions. The histopathological examination of the excised lesion showed small islands and cords of odontogenic epithelium with cellular myxoid stroma in the subepithelial tissue. The mass contained calcified material and an enamel-like deposit. Many small blood vessels appeared in the connective tissue surrounding the odontogenic epithelium. The immunohistochemical assays showed strong reactivity for amelogenin, β-catenin, CD44, and CD31 in the tissue sections. There was no recurrence after the 1-year follow-up. Because this lesion clinically resembles other nonneoplastic lesions and is very rare in gingiva, establishing a correct diagnosis is achieved only based on specific histological characteristics. Conservative excision of the tumor is the treatment of choice.

Ameloblastic fibrodentinoma with a congenitally missing second premolar tooth: a case report

Ameloblastic fibrodentinoma (AFD) is a rare benign mixed odontogenic tumor that occurs predominantly in children and young adults. AFD is usually associated with delayed eruption of the tooth and shows painless swelling. We present a case of AFD affecting an 8-year-old Japanese girl with a complaint of delayed eruption of her left mandibular second premolar tooth. Intraoral examination did not reveal any sign of pain or swelling in the left mandible. Panoramic radiography revealed a radiolucent and well-circumscribed lesion, which contained radiopaque material at the premolar lesion of the left mandible. The second deciduous molar tooth was unerupted and the second premolar tooth was congenitally lacking. Our provisional diagnoses were odontogenic tumor. The biopsy confirmed AFD. The treatment included total excision of the tumor and the second premolar tooth. No recurrence has been noted during the 2 years of follow-up.

Central granular cell odontogenic tumor: a systematic review

Central granular cell odontogenic tumor (CGCOT) is a rare benign odontogenic neoplasm reported with various terms and is not included in the 2005 WHO classification of odontogenic tumors. It shows a predilection for middle-aged women, usually presenting as an asymptomatic swelling of the mandibular premolar-molar region. Radiographic manifestations include unilocular or multilocular radiolucent lesion, but mixed density lesions can also occur. Histopathology shows sheets and lobules of round to polygonal cells with abundant eosinophilic, granular cytoplasm and eccentrically placed nuclei. Immunohistochemical and ultrastructural features suggest the histiocytic origin of granular cells. The neoplasm does not exhibit an aggressive biological behavior and hence enucleation or curettage ensuring complete removal remains the treatment of choice. We present a systematic review on clinical, radiological, histopathological, immunohistochemical and treatment aspect of CGCOT. Published articles were identified through a literature search using online databases (PubMed, MEDLINE, Scopus) and cross-references for papers published from the year 1950 to March 2013. From a total of 37 papers, 26 (38 cases) were extracted from the database for systematic review.

Locally infiltrative ameloblastic fibroma in a rhesus macaque (Macaca mulatta) with characterizations of its proliferating activity and biological behavior

An 8-year-old male rhesus macaque (Macaca mulatta) presented with unilateral enlargement of the left mandible. Radiographs revealed a marked expansion of the left mandible with a multilocular radiolucent mass with abundant osteolysis. The mass was grossly firm, fleshy, and gelatinous on the cut surface. Histologically, the mass was locally infiltrative and composed of neoplastic epithelial and mesenchymal components that stained positive for cytokeratin and vimentin, respectively. Occasional densely spherical condensations of fibroblasts resembling the cap stage of odontogenesis were present in the mesenchyma. Immunohistochemical staining with Ki-67, S-100, and CD34 indicated that both epithelial and mesenchymal components of the neoplasm had low proliferation. Alcian blue, periodic acid-Schiff, and trichrome stains showed an immature stromal component with no collagen formation. Based on the clinical, histologic, and immunophenotypic features, the tumor was identified as a locally infiltrative ameloblastic fibroma.

Loss of heterozygosity (LOH) in tumour suppressor genes in benign and malignant mixed odontogenic tumours

Although molecular alterations are reported in different types of odontogenic tumours, their pathogenesis remains to be established. Loss of heterozygosity (LOH) studies allow the identification of minimal regions of deletions of known or putative tumour suppressor genes, the losses of which may promote neoplastic growth. The purpose of this study was to investigate LOH in a set of odontogenic mixed tumours. Tumour suppressor gene loci on 3p, 9p, 11p, 11q and 17p chromosomes were analysed in five samples of ameloblastic fibroma (AF), three samples of ameloblastic fibro-odontoma (AFO) and three samples of ameloblastic fibrosarcoma (AFS). The most frequently lost genetic loci were p53 (17p13, 62%) and CHRNB1 (17p13, 55%). LOH at the chromosome regions 3p24.3, 9p22 and 9p22-p21 was identified only in AFS. No sample showed LOH at the chromosomal loci 3p21.2 and 11q13.4. For the region 9p22-p13, LOH occurred in one sample of AFO. The fractional allelic loss (FAL) was calculated for each sample. The mean FAL of the benign lesions (i.e. AF and AFO) was 22%, whereas the mean FAL of the malignant lesions (i.e. AFS) was 74.6%. In conclusion, our results show a higher FAL in AFS compared to its benign counterparts and reveal a different pattern of LOH of tumour suppressor genes in AFS, which may regulate changes in tumour behaviour.

A previously unreported malignancy of the thyroid

Ameloblastic fibrosarcoma or ameloblastic sarcoma is an extremely rare odontogenic neoplasm. We report a case of an ameloblastic fibrosarcoma arising from thyroid gland in a 44 year-old woman. Following total thyroidectomy, a histopathologic, immunohistologic, and genotypic examination revealed ameloblastic fibrosarcoma. The tumor was composed of odontogenic epithelium, resembling that of ameloblastoma, and a mesenchymal part exhibiting features of fibrosarcoma. To our review, our case represents the first report of ameloblastic fibrosarcoma of the thyroid gland. Ameloblastic fibrosarcoma may arise from thyroid gland.

Ameloblastic fibrosarcoma involving the anterior and middle skull base with intradural extension

Ameloblastic fibrosarcoma is a malignant odontogenic tumor that rarely affects the skull base and surrounding regions. We present a case of a 48-year-old man with histologically confirmed malignant transformation of a benign ameloblastic fibroma 10 years after initial presentation of a localized facial mass. The ameloblastic fibrosarcoma extended from the facial region to the orbit, anterior and middle fossa skull base, the infratemporal fossa, and the cavernous sinus. Progressive proptosis with complete monocular vision loss was the presenting symptom. To our review, our case represents the first report of intradural extension of ameloblastic fibrosarcoma. Using a multidisciplinary skull base approach, resection of all tumors except that in the cavernous sinus was achieved with the resulting defect reconstructed with an anterolateral thigh free flap. The patient had no new neurologic deficits after surgery and underwent adjuvant fractionated radiation therapy. Malignant transformation of ameloblastic fibroma into ameloblastic fibrosarcoma can occur many years after initial presentation. Thus, vigilant long-term follow-up is essential despite the benign nature of the initial pathologic lesion. Use of a multidisciplinary approach is critical in obtaining the optimal outcome in these complex cases.

[Mixed odontogenic tumours]

Mixed odontogenic tumors include all tumors of the teeth both epithelial and mesenchymatous. Most of these tumors are rare (ameloblastic fibroma, ameloblastic fibro-odontoma and fibrodentinoma, odontoameloblastoma, calcified odontogenic cyst). Other tumors such as odontoma are frequent. They have in common a benign aspect, their often-fortuitous observation, a higher rate in the young adult and surgical treatment by complete exeresis preventing recurrence. They present a radiolucent lacuna but appear different depending on the presence or not of intralesional calcifications revealing the production of more or less mature dental tissue. The diagnosis may be confirmed only by an anatomopathological examination, along with clinical and radiological observations.

Ameloblastic fibro-odontosarcoma: a case report

This paper reports one case, of an ameloblastic fibro-odontosarcoma (AFOS) affecting the mandible, in a 12-year-old girl. This neoplasm is a rare odontogenic neoplasm. To the authors' knowledge this is the fifteenth case of AFOS reported in English. The patient's chief complaint was a swelling in the face for 6 months. An incisional biopsy was performed diagnosing the case as an ameloblastic fibroma. After radiography ameloblastic fibro-odontoma was diagnosed. Computed tomography was performed and a stereolithography model made to plan the surgical procedures. A hemimandibulectomy followed by a vascularized fibular flap was then proposed. The surgery was uneventful. Microscopic features diagnosed an AFOS. After 23 months of close follow-up there is no sign of recurrence or metastasis. Dental implants were recently placed in the fibular flap.

Ameloblastic fibro-odontoma: expansile mixed radiolucent lesion in the posterior maxilla: a case report

Ameloblastic fibro-odontoma (AFO) is a benign tumor that displays properties of both ameloblastic fibroma and compound odontoma. Often, AFO presents clinically as a hamartoma or immature odontoma; however, the tumor can also present with progressive growth causing bone destruction and significant deformity, acting more like a true neoplasm. We report a case of a locally aggressive AFO in the posterior maxilla of a 7-year-old girl and discuss the clinical, radiographic, histopathologic, and conservative therapeutic approach to this locally aggressive tumor.

An unusual size of ameloblastic fibro-odontoma

Ameloblastic fibro-odontoma (AFO) is a quite rare, mixed odontogenic tumour generally seen in the early stages of life. Frequent signs of the tumour are asymptomatic swelling, delayed tooth eruption and mixed radiological appearance within well-defined borders. Management of the lesion includes enucleation of the tumour and long-term follow-up in order to avoid recurrence. A 9-year-old girl was referred to our clinic with swelling in her right cheek. After clinical and radiographic examination, a large lobular radiopaque mass with a radiolucent border covering the complete right maxillary sinus was observed. Under general anaesthesia, the lobules of the lesion were enucleated and the permanent right lateral incisor and canine teeth were left for eruption. Histological assessment revealed a final diagnosis of ameloblastic fibro-odontoma. Post-operative healing was uneventful and the remaining teeth erupted normally. No recurrence was observed during the 3 years' follow-up period.

Management of ameloblastic fibro-odontoma in a 6-year-old girl preserving the associated impacted permanent tooth

The ameloblastic fibro-odontoma (AFO) is a rare odontogenic tumor that occurs predominantly in children and is generally associated with unerupted teeth. The choice of treatment for this entity is conservative surgery with enucleation and its prognosis is excellent. However, preserving the associated impacted teeth may make complete removal of the lesion difficult and may explain some cases of recurrence. A case of AFO in a 6-year-old girl treated with enucleation and preservation of an impacted lower left first permanent molar is reported. After two years of follow-up, there were no signs of recurrence and complete spontaneous eruption of the preserved tooth was observed. The present report indicates that the degree of involvement of the impacted tooth by AFO is a fundamental aspect to be considered during radiological analysis and surgical assessment. We concluded that preservation of the impacted permanent teeth associated with this tumor should always be considered and carried out with caution, since they are clearly not included in the surgical cavity.

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.

Anaplastic ameloblastic fibrosarcoma arising from recurrent ameloblastic fibroma: restricted molecular abnormalities of certain genes to the malignant transformation

A rare case of anaplastic ameloblastic fibrosarcoma (AS) arising in an ameloblastic fibroma (AF) of the maxilla of a 48-year-old patient 10 years after the primary excision is presented. The recurrent tumor retained focal areas of AF but manifested heterogeneous malignant features ranging from low-grade spindle to highly pleomorphic sarcomas. Biomarker analysis showed alterations of the p53 and c-KIT genes restricted to the sarcomatous component. The biological implications of these findings in the future management of these tumors are discussed.

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.

Ameloblastic fibroma and related lesions: a clinicopathologic study with reference to their nature and interrelationship

BACKGROUND

Ameloblastic fibroma (AF) and related lesions constitute a group of lesions, which range in biologic behavior from true neoplasms to hamartomas. The aim of this study was to elucidate the nature and interrelationship of this group of lesions.

METHODS

Clinical and pathological studies were undertaken retrospectively on 13 cases of AF and seven cases of ameloblastic fibro-odontoma (AFO). Thirty-three complex odontomas and 33 compound odontomas were also included for comparative purpose. Relevant follow-up data were recorded and the literature was reviewed.

RESULTS

The majority of patients with AF (nine cases, 69.2%) were over the age of 22 years with frequent involvement (76.9%) of the posterior mandible. Tumors recurred in four of 11 patients with follow-up information and two recurrent tumors showed malignant transformation. There was no case in this series that could be designated as the so-called ameloblastic fibrodentinoma, apart from one recurrent AF in which further maturation to form only tubular dentin materials was identified. AFO tended to occur at a younger age group with an average of 9.6 years. Recurrence was noted in two of five patients with follow-up data and both recurrent lesions showed limited growth potential and further maturation into a complex odontoma. Significant differences were noted in the age and site distribution between the complex and the compound odontomas.

CONCLUSION

Whilst the majority, if not all, of AFs are true neoplasms with a potential to recur and/or of malignant transformation, some, especially those occurred during childhood, could represent the primitive stage of a developing odontoma. Our data also suggests that some AFOs are hamartomatous in nature, representing a stage preceding the complex odontoma.

Potential pitfalls in diagnostic oral pathology: a review for the general surgical pathologist

Oral developmental, reactive, benign neoplastic and malignant neoplastic conditions, many odontogenic in origin, may not be seen routinely by the general surgical pathologist and therefore may present a diagnostic dilemma. This article describes odontogenic and nonodontogenic conditions with little or no destructive potential along with the more aggressive conditions that resemble them clinically and histologically. The importance of clinical and radiographic correlation as an adjunct to tissue diagnosis is highlighted. Additionally, a brief summary of odontogenesis is presented with attention given to odontogenic embryologic remnants and the developmental and pathologic processes that may arise from them.

Malignant transformation of ameloblastic fibroma to ameloblastic fibrosarcoma: case report and review of the literature

INTRODUCTION

Ameloblastic fibrosarcoma is a rare malignant odontogenic tumour and is regarded as the malignant counterpart of the ameloblastic fibroma. The epithelial component remains benign, but the mesenchymal component becomes malignant. The diagnosis is made by histopathology.

PATIENT

The case of a 26-year-old man who underwent curettage of an ameloblastic fibroma and died of an ameloblastic fibrosarcoma is presented, and the course of malignant transformation is analysed retrospectively.

CONCLUSION

One-third of ameloblastic fibrosarcoma cases seem to have developed from recurrent ameloblastic fibromas. Knowledge of the malignant potential in the mesenchymal spindle cells of ameloblastic fibroma will assist in determining the management of these benign tumours, and may prevent malignant transformation to ameloblastic fibrosarcoma.

Ameloblastic fibroma of the maxillary sinus

Ameloblastic fibroma is a rare true mixed tumor of odontogenic origin with both mesenchymal and ectodermal components. It usually arises from the mandibular dentition and presents in the second decade of life. It is a benign slow growing tumor that is less infiltrative than an ameloblastoma but tends to expand bone. It infrequently involves the maxilla and hence the management of these tumors in that region is controversial. The goal of therapy is to avoid cosmetic deformity without compromising on tumor eradication. We present the tenth reported case of this type of tumor in the maxilla, and the second one in an infant.