Maxillary Ameloblastoma in an Asiatic Black Bear (Ursus thibetanus)

An approximately 30-year-old intact female Asiatic black bear (Ursus thibetanus) was presented for annual examination and a history of ptyalism. A large 9.5 cm × 5 cm × 5 cm, firm, round mass was identified attached to the hard palate on physical examination. A computed tomography scan was performed, and the heterogeneous, mineral-attenuating mass was seen arising from the right aspect of the palatine bone and extending rostrally to the level of the last maxillary molars, caudally into the oropharynx, and dorsally into the nasal choana. Surgical debulking was performed to remove the portion of the mass within the oral cavity. Histopathologic analysis was consistent with a keratinizing ameloblastoma. Nine months postoperatively, the patient was asymptomatic for the tumor. The patient was euthanized 23-months postoperatively, and severe diffuse pustular dermatitis, growth of the ameloblastoma on the hard palate, and various degenerative and aging changes were noted on necropsy at that time. This is the first report of an ameloblastoma in a member of the Ursidae family.

Targeted therapies in ameloblastomas and amelobastic carcinoma-A systematic review

Targeted therapy has the potential to be used in the neoadjuvant setting for odontogenic tumors, reducing the morbidities associated with major surgery. In this regard, the aim of this study was to summarize the current evidence on the different forms of targeted therapy, effectiveness, and drawbacks of this course of treatment. Four databases were searched electronically without regard to publication date or language. Grey literature searches and manual searches were also undertaken. Publications with sufficient clinical data on targeted therapy for odontogenic tumors were required to meet the criteria for eligibility. The analysis of the data was descriptive. A total of 15 papers comprising 17 cases (15 ameloblastomas and 2 ameloblastic carcinomas) were included. Numerous mutations were found, with BRAF V600E being most common. Dabrafenib was the most utilized drug in targeted therapy. Except for one case, the treatment reduced the size of the lesion (16/17 cases), showing promise. Most of the adverse events recorded were mild, such as skin issues, voice changes, abnormal hair texture, dry eyes, and systemic symptoms (e.g., fatigue, joint pain, and nausea). It is possible to reach the conclusion that targeted therapy for ameloblastoma and ameloblastic carcinoma may be a useful treatment strategy, based on the findings of the included studies.

Ameloblastic Carcinoma of the Maxilla With Uncommon Sinus Manifestations

Ameloblastic carcinoma (AC) represents a distinct challenge in the realm of odontogenic malignancies due to its rarity and aggressive nature. We present a unique case of AC in a 70-year-old male, retired dry cleaner, with symptoms initially suggestive of chronic allergic rhinitis and recurrent acute sinusitis with asymmetric facial edema and paresthesia. Detailed evaluation revealed a prominent mass in the right maxillary sinus with extensive cortical destruction. Pathological assessment post-right maxillectomy identified a high-grade AC with malignant spindle cell transformation. The patient underwent subsequent interventions, including neck dissection and radiation therapy. Twelve months post-presentation, the patient was recovering appropriately without evidence of recurrence of malignancy. This case highlights the diagnostic challenges posed by AC as well as its unique presentations emphasizing the importance of a comprehensive approach and multidisciplinary management. It also raises considerations about potential chemical exposure implications in AC development.

An Unusual Case Report of Unicystic Ameloblastoma of the Mandible

There are plenty of benign lesions that can result in swelling of the mandible, and these can be classified as odontogenic and non-odontogenic lesions. Among the categories of odontogenic lesion, ameloblastoma is the most occurring lesion that takes origin from the epithelial cellular elements and dental tissues in their different stages of development. Ameloblastoma is the most serious odontogenic neoplasm due to its prevalence and clinical characteristics. Ameloblastoma is a broad class which encompasses 80% of solid multicystic type of ameloblastoma with unicystic ameloblastoma (UA) variant included as vital clinicopathological form claiming the rest 20% along with peripheral ameloblastoma variant. UA refers to cystic lesions that seem like jaw cysts clinically, radiographically, or grossly but are lined by typical ameloblastomatous epithelium, with or without luminal and/or mural tumor development, on histologic investigation. Around 5-15% of all ameloblastic lesions do not have a propensity to metastasis, and this is UA. Unicystic mural form, although slow growing overall, is very invasive locally and has a high recurrence rate. As UA tumors show very close features with dentigerous cyst, a very sharp differential diagnosis protocol need to be executed to exclude the other unicystic odontogenic lesions considering the clinical, radiological, and biological characteristics along with proper follow-up and seeing any recurrence of the lesion taking place. Here, we report the case of a twenty-one year male patient with UA of the mandible and review of the literature.

Unraveling the Enigma of Managing a Large Periapical Lesion: A Case Report

This case report documents the diagnosis and successful management of a substantial periapical lesion located in the lower left region of the jaw. The patient presented with clinical symptoms indicative of periapical pathology, and radiographic examination revealed an extensive radiolucent lesion. The chosen treatment approach involved endodontic intervention coupled with surgical decompression, leading to the resolution of the lesion and restoration of oral health. This case underscores the significance of an accurate diagnosis and a multidisciplinary treatment approach in addressing large periapical lesions.

Spontaneous mandibular follicular ameloblastoma in a female Sprague-Dawley rat

Ameloblastoma is a locally aggressive tumor derived from the odontogenic epithelium of the developing tooth germ. It is rarely reported in experimental Sprague-Dawley (SD) rats. In this 90-day percutaneous repeated-dose toxicity study, mandibular nodules were observed from day 56 to 90. Upon necropsy, a well-demarcated nodule, approximately 1.2×1.0×1.0 cm, was found attached to the mandibular bone, alongside the unerupted left incisor. Histopathologically, the epithelial cells formed islands, nests, or anastomosing strands. The epithelial islands were surrounded by a peripheral layer of tall columnar cells with antibasilar nuclei arranged in a palisading pattern. Several mitotic cells were observed. Some epithelial islands displayed cystic degenerative changes and squamous metaplasia. Necrotic tissue with inflammatory cell infiltration was observed at the tumor margins. Immunohistochemically, the neoplastic epithelial islands and mesenchymal components exhibited positivity for pan-cytokeratin and vimentin, respectively. Based on these features, the case was diagnosed as follicular ameloblastoma in an SD rat.

Symphyseal-Sparing Mandibulectomy for Canine Acanthomatous Ameloblastoma in Dogs: 35 Cases

Canine acanthomatous ameloblastoma (CAA) has been reported to be the most prevalent odontogenic tumor in dogs. The most common location of this tumor is the rostral mandible. Symphyseal-sparing mandibulectomy has been shown to be an effective technique to maintain mandibular continuity and promote early return to function. In this retrospective study, 35 dogs with CAA associated with a mandibular canine tooth were evaluated following a symphyseal-sparing rostral mandibulectomy. Dogs with intraoperative transection of the canine tooth root and subsequent root fragment extraction were included. The objective of this study was to evaluate outcome following excision of CAA with mid-root transection. Data retrospectively evaluated in this study included the following: narrowest tumor margin, narrowest tumor margin at the border associated with the transected canine root, tumor size, and prevalence of local recurrence. This study showed that 82.86% of CAA were completely excised with tumor-free margins (N = 29). The median narrowest overall tumor-free margin was 3.5 mm (interquartile range [IQR] 2.0-6.5 mm) and the median tumor-free margin associated with the border of the transected canine root was 5.0 mm (IQR 3.1-7.0 mm). Follow-up data was obtained in 25 cases via phone interviews with referring veterinarians and clients. No local tumor recurrence was reported in cases with incomplete tumor excision (N = 5). All dogs with follow-up data survived at least 1 year following surgery. It was concluded that segmental or rostral mandibulectomy with wide margins to include the entire mandibular canine tooth with subsequent mandibular instability may not be warranted for dogs with CAA associated with this tooth.

Non-invasive and Locally Invasive Hypercellular Peripheral Odontogenic Fibroma in 20 Dogs

Medical records of dogs with an initial histopathological diagnosis of odontogenic sarcoma were reviewed for information on signalment, body weight, medical history, clinical signs, physical examination and diagnostic imaging findings, surgical procedure performed, and histologic characteristics. Twenty dogs were deemed to fit the criteria following the rigorous histology review process. These tumors were characterized by hypercellularity of the spindle cell component with less intervening stroma, mitotic activity, and variable presence of odontogenic epithelium and hard substance (cementum/dentin/bone). Non-invasive or locally invasive hypercellular peripheral odontogenic fibroma is suggested by the authors to describe these tumors. There were no signs of recurrence of any of the masses following surgical excisions with varying margins.

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.

Management of Mandibular Compound Odontoma With Numbness in the Lower Jaw

Odontomas are considered to be among the more common odontogenic tumors in the oral cavity. Several authors classify them as hamartomas instead of actual tumors. Odontomes' precise etiology is still unknown. The majority of odontomas are found during routine radiography studies and are asymptomatic. Odontomes typically cause disruptions to the teeth's eruption, most frequently deflection or delayed eruption. Here, the reported study details the surgical management of a mandibular compound odontoma in a patient who presented with a complaint of numbness in his lower jaw.

Dentinogenic ghost cell tumor associated with odontoma: report of a rare case and review of literature

Dentinogenic ghost cell tumor (DGCT) is an uncommon odontogenic tumor considered to be the solid, tumorous variant of calcifying odontogenic cyst. DGCT is characterized by islands of ameloblastoma-like epithelial cells that resemble the enamel organ, the presence of ghost cells, and dentinoid material. This article reports a rare case of dentinogenic ghost cell tumor associated with an odontoma in an adult patient, with a review of the literature. To the best of the authors' knowledge, there have only been four case reports of DGCT associated with odontoma, all of which occurred in children and adults younger than 30 years old.

Ameloblastic Fibro-Odontoma of the Posterior Mandible: A Rare Pathological Entity

Ameloblastic fibro-odontoma (AFO) is a rare, slow-growing neoplastic lesion classified as a benign, epithelial mixed odontogenic tumor with odontogenic mesenchyme. This tumor demonstrates the histological features characteristic of both ameloblastic fibromas and complex odontomas. The clinical manifestation of AFO is typically characterized by asymptomatic enlargement of the jawbones. Radiographically, it presents as a distinct radiolucent region, indicating the presence of radiopaque substances with varying degrees of irregularities in size and morphology. Standard therapeutic intervention involves enucleation. Despite its benign nature, AFO can cause significant morbidity if left untreated. Therefore, prompt diagnosis and appropriate management are essential to ensure optimal patient outcomes. The following case report details the clinical presentation and management of an 18-year-old male with an AFO lesion located in the posterior mandible. This particular case was treated with conservative measures involving surgical enucleation.

The Stem Cell Expression Profile of Odontogenic Tumors and Cysts: A Systematic Review and Meta-Analysis

BACKGROUND

Stem cells have been associated with self-renewing and plasticity and have been investigated in various odontogenic lesions in association with their pathogenesis and biological behavior. We aim to provide a systematic review of stem cell markers' expression in odontogenic tumors and cysts.

METHODS

The literature was searched through the MEDLINE/PubMed, EMBASE via OVID, Web of Science, and CINHAL via EBSCO databases for original studies evaluating stem cell markers' expression in different odontogenic tumors/cysts, or an odontogenic disease group and a control group. The studies' risk of bias (RoB) was assessed via a Joanna Briggs Institute Critical Appraisal Tool. Meta-analysis was conducted for markers evaluated in the same pair of odontogenic tumors/cysts in at least two studies.

RESULTS

29 studies reported the expression of stem cell markers, e.g., SOX2, OCT4, NANOG, CD44, ALDH1, BMI1, and CD105, in various odontogenic lesions, through immunohistochemistry/immunofluorescence, polymerase chain reaction, flow cytometry, microarrays, and RNA-sequencing. Low, moderate, and high RoBs were observed in seven, nine, and thirteen studies, respectively. Meta-analysis revealed a remarkable discriminative ability of SOX2 for ameloblastic carcinomas or odontogenic keratocysts over ameloblastomas.

CONCLUSION

Stem cells might be linked to the pathogenesis and clinical behavior of odontogenic pathologies and represent a potential target for future individualized therapies.

A Painless Bump: A Case Report of Cemento-Ossifying Fibroma of the Anterior Maxilla

Cemento-ossifying fibroma (COF) is a benign odontogenic neoplasm. It is considered an ossifying fibroma with traces of interspersed cementum fragments. Here we present a case report of the occurrence of COF in the maxillary anterior region of an elderly woman. A 61-year-old female reported with a painless, progressive, slow-growing swelling on the upper front jaw region for the past five years. A single, localized, swelling on the anterior region of the maxilla which was non-tender and bony hard in consistency. Radiological examination consisting of orthopantomagram (OPG) and cone-beam computed tomography (CBCT) revealed increased thickness of bone over frontal, parietal and maxilla with alteration of trabecular pattern - cotton wool/ground glass. Serum alkaline phosphatase level was found to be 865 U/l, however, serum calcium level and other routine blood investigations (hemogram) were within normal limits. The above radiological and laboratory findings are more in favour of primary bone pathology and with a biopsy later correlating with histopathological findings; it was diagnosed as COF. Under conscious sedation, surgical excision of the bony mass was done along with extraction of associated teeth. The patient is currently on regular follow-up and planning for a dental prosthesis is in progress.

A massive dentinogenic ghost cell tumor that crossed the midline: A rare case report

Dentinogenic ghost cell tumor (DGCT) is a rare tumor of odontogenic origin. A locally invasive lesion can be described by the presence of ameloblast-like epithelial islands, ghost cells, and dentinoid material. It is one of the few lesions with a predilection for the Asian population. The available literature has revealed that only 131 cases to date have been reported and published from 1968 to 2022. The following is a case report of a 25-year-old male with a tumor in the left lower back teeth region for the past 1 month. Orthopantomogram (OPG) reveals a well-defined unilocular radiolucency extending anteroposteriorly and crossing the midline. Histopathology revealed basal ameloblast-like cells and central stellate reticulum-like cells with the characteristic presence of ghost cells. The diagnosis was made based on the clinical, radiographical, and histopathological correlation and was confirmed using immunohistochemical analysis as a DGCT.

Desmoplastic Ameloblastoma-A Case Report

Desmoplastic ameloblastoma (DA) is a rare variant of conventional ameloblastoma. It accounts for only 4%-13% of all ameloblastomas. DA was included in the World Health Organization Classification of Head and Neck Tumors (WHO-2005) as a variant of ameloblastoma with specific clinical, imaging, and histological features. The desmoplastic variant of ameloblastoma usually appears in the anterior and premolar regions as a mixed radiolucent and radiopaque lesion, sometimes resembling a benign fibro-osseous lesion.Ameloblastoma is a locally aggressive tumor that may cause recurrence and in rare cases, malignant transformation with repeated postsurgical recurrences. In this paper, we present a case of a 28-year-old female with swelling in the left upper jaw, a biopsy of which turned out to be DA.

Maxillary neoplasms in four dromedary camels

Four camels (Camelus dromedarius) presented to the Veterinary Teaching Hospital at King Faisal University with maxillary masses. On radiographs, the masses were multicystic and expanded the maxillary bone. The tumors were diagnosed by histopathologic examination as conventional ameloblastoma, two cases as intraosseous squamous cell carcinoma, and central odontogenic fibroma with ossification. To the authors' knowledge, this is the first report of ameloblastoma in a camel, the first detailed description of maxillary squamous cell carcinoma in camels, and the first report of central odontogenic fibroma in any animal species.

Compound Odontoma and Dentigerous Cyst Associated With an Unerupted Maxillary Canine Tooth in a Weimaraner Dog: A Case Report

A 7-month-old, male, Weimaraner dog was presented for maxillary swelling. Clinical evaluation including radiographs and computed tomography revealed a large cystic lesion, unerupted right maxillary canine tooth, and mass presumed to be a compound odontoma. The cyst and mass were expansile and occupied a large portion of the nasal cavity displacing anatomical structures of the maxilla. The mass was excised via curettage through an intraoral surgical approach and the unerupted tooth and cystic lining were removed. Histopathology supported dentigerous cyst and compound odontoma. This case confirms the first report of concurrent development of dentigerous cyst and compound odontoma in a dog with successful treatment and 18-month follow-up with no recurrence.

Odontogenic myxoma of the mandible: a case report

The odontogenic myxoma is a tumor of the jaws which arises from the mesenchymal portion of the tooth germ, either the dental papilla, the follicle, or the periodontal ligament. It is a slow-growing, painless, nonmetastasizing, central tumor of the jaws, chiefly the mandible. Radiographically, the classic presentation may vary from a unilocular radiolucency to a multilocular lesion with well-defined or diffuse margins. On histological study, it is composed of triangular or stellate connective cells, anastomosed by fine extensions, and embedded in abundant mucoid material.

Case presentation

We present the unusual case of an odontogenic myxoma involving a 37-year-old female patient, which had acquired large dimensions and involved the right half of the mandible, including the ramus; the patient was treated with large resection surgery, with satisfying medium-term results.

Clinical discussion

Early diagnosis of such lesions is very important, as the patient avoids extensive surgical procedures that involve losing a large part of the jawbones and their subsequent impact on the patient's quality of life.

Conclusion

Although there is no fixed treatment plan for the management of odontogenic myxoma, treatment includes surgical management that may range from simple enucleation and curettage to surgical excision; wide surgical resection is appropriate for cases of large size to avoid recurrence.

A rare case of dentinogenic ghost cell tumor with concomitant odontoma

Key Clinical Message

A case of dentinogenic ghost cell tumor occurring simultaneously with a clinically diagnosed odontoma. The occurrence of epithelial and mesenchymal tumors at the same site is very rare, but should be kept in mind during pathological diagnosis.

Abstract

Dentinogenic ghost cell tumor (DGCT) is a rare and benign odontogenic tumor composed of ghost cells, calcified tissue, and dentin. We present an extremely rare case of a 32-year-old female who was clinically diagnosed with an odontoma presenting with a painless swelling in her maxilla. Radiographic examination showed a well-defined radiolucent lesion with tooth-like calcified areas. The tumor was resected under general anesthesia. No recurrence was noted at the 12-month follow-up. Histopathological examination of the surgically resected tumor yielded a diagnosis of DGCT with odontoma.

Central Granular Cell Odontogenic Tumor: Review of Cases Reported in the Last 71 years and Report of a Case

Central granular cell odontogenic tumors (CGCOTs) are rare, benign, slowly growing odontogenic neoplasms. Due to their uncertain histogenesis, CGCOTs are still not included as a distinct entity in the WHO classification (2017) of odontogenic tumors. We report a case of CGCOT involving the right side of maxillary anterior region of a 39-year-old white female. Immunohistochemical staining showed granular cells positively expressed CD68 and vimentin, and negatively expressed S-100 protein. Meanwhile, we searched PubMed, Google Scholar, and Scopus databases to summary the clinico-pathological features of 51 published cases of CGCOT. The results showed the granular cells of 28.6% cases were immunopositive for vimentin and CD68, and odontogenic epithelial cells positive immunoreactivity for cytokeratin. These findings reinforced the mesenchymal origin of granular cells and the odontogenic nature of epithelium islands.

Interrogation of TERT promoter hotspot mutations in ameloblastoma and ameloblastic carcinoma

BACKGROUND

TERT promoter mutations increase telomerase activity, conferring cell immortality. The coexistence of TERT promoter mutations with BRAFV600E is associated with aggressiveness. Ameloblastoma and ameloblastic carcinoma are infiltrative neoplasms that harbor BRAFV600E; however, it remains unknown if these odontogenic tumors also show TERT promoter mutations.

METHODS

Genomic DNA of paraffin-embedded ameloblastomas (n = 6) and ameloblastic carcinomas (n = 3) were Sanger-sequenced to assess the hotspot TERT promoter mutations C228T and C250T. BRAFV600E status was screened by TaqMan allele-specific quantitative polymerase chain reaction.

RESULTS

None of the samples harbored TERT promoter mutations. The BRAFV600E mutation was positive in 3 of 6 of ameloblastomas and in 1 of 3 of ameloblastic carcinomas.

CONCLUSION

The absence of TERT promoter mutation in the samples indicates that this molecular event is not relevant to the tumors' pathogenesis. Further studies are necessary to explore undefined genetic or epigenetic mechanisms related to TERT-upregulation in ameloblastoma, and the telomerase activity in ameloblastic carcinoma.

Odontogenic keratocyst in the mandibular condyle base region: A case report

Odontogenic keratocysts (OKCs) often occur in the molars in the mandibular ramus; they often progress asymptomatically and are discovered only after widespread development. Some cases of OKC progress to the mandibular condyle; however, very few cases exist only in the condyle. To the best of our knowledge, in all of the previously reported cases, OKCs occurred in the mandibular ramus, which underwent resection. The present study reports the case of a 31-year-old man in whom an OKC (13x12x6 mm) occurred discretely in the base of the condyle, in which the condylar head was successfully preserved. The tumor was removed under general anesthesia using the approach of shaving the anterior surface of the mandible. The extraction cavity was managed using the packed open technique and with an obturator. Approximately 20 months post-operation, the patient remained recurrence-free. This report presents a rare case of an OKC in the mandibular condyle base region. Resection was performed under general anesthesia and the condylar process was successfully preserved.

Benign Pediatric Jawbone Lesions: A 10-Year Clinical and Radiological Pilot Study

This study aimed at presenting a retrospective longitudinal analysis of the pediatric jaw lesions treated at the Oral and Maxillofacial Surgery Clinic in Cluj-Napoca, Romania, over a timeframe of ten years (2012 to 2022). The clinical and radiological characteristics of the jawbone lesions, the treatment outcome, and the recurrence incidence were described. All consecutive patients aged below 18 years, with histologically diagnosed odontogenic tumors (OTs), nonodontogenic tumors (non-OTs), or odontogenic cysts (OCs) were included. Age, dentition type, clinical symptoms, preoperative and postoperative radiological tests, histological diagnosis, treatment, and follow-up information one year following the diagnoses were all examined. Eighty-two cases were included. The ratio of men to women was 1.15:1, with the mandible predominating by 64.4%. Inflammatory radicular cysts predominated in 31.7% of cases. A total of 42.68% of the patients were asymptomatic. Enucleation was the most frequent surgical technique (45.1%), followed by cystectomies (28%) and marsupialization (14.6%). The overall recurrence rate was 7.3%; the most recurrent histopathological lesion was the odontogenic keratocyst. This study sheds new light on the clinical and radiological characteristics, treatment outcomes, and recurrence rate of juvenile jawbone lesions in children and adolescents. The diagnosis and treatment of jawbone lesions in children and adolescents can be enhanced with the use of epidemiological, clinical, and imagistic information.

IL-6 Plays a Critical Role in Stromal Fibroblast RANKL Induction and Consequent Osteoclastogenesis in Ameloblastoma Progression

Ameloblastoma (AB) is the most common benign, epithelial odontogenic tumor that occurs in the jawbone. AB is a slow-growing, benign epithelial tumor but shows locally invasive growth, with bone resorption or recurrence if not adequately resected. From these points of view, understanding the mechanism of AB-induced bone resorption is necessary for better clinical therapy and improving patients' quality of life. In bone resorption, osteoclasts play critical roles, and RANKL is a pivotal regulator of osteoclastogenesis. However, the source of RANKL-expressing cells in the AB tumor microenvironment is controversial, and the mechanism of osteoclastogenesis in AB progression is not fully understood. In this study, we investigated the distribution of the RNA expression of RANKL in AB specimens. We found that PDGFRα- and S100A4-positive stromal fibroblasts expressed RANKL in the AB tumor microenvironment. Moreover, we analyzed the mechanisms of osteoclastogenesis in the AB tumor microenvironment using the human AB cell line AM-1 and a human primary periodontal ligament fibroblast cells. The results of histopathologic and in vitro studies clarified that the interaction between AB cells and stromal fibroblasts upregulated IL-6 expression and that AB cells induced RANKL expression in stromal fibroblasts and consequent osteoclastogenesis in AB progression.

Conventional Ameloblastoma. A Case Report with Microarray and Bioinformatic Analysis

Ameloblastoma is a rare benign epithelial odontogenic neoplasm, but with great clinical implications, as despite its benignity and slow growth, most cases are locally aggressive with a significant recurrence rate. Histological, cellular, or molecular analyses of its pathogenesis have confirmed the complexity of this neoplasm. We present the case of a 20-year-old patient with a suggestive clinical and radiographic diagnosis of ameloblastoma. An incisional biopsy was obtained confirming the diagnosis of conventional ameloblastoma. Left hemimandibulectomy and plate reconstruction were performed. Histopathological analysis of the surgical specimen confirmed the conventional ameloblastoma with a plexiform pattern and significant areas of cystic degeneration and amyloid-like-like deposits. Additionally, a microarray was carried out with bioinformatic analysis for the enrichment, protein interaction, and determination of eight hub genes (CRP, BCHE, APP, AKT1, AGT, ACTC1, ADAM10, and APOA2) related to their pathogenesis.

Two sides of a coin: A report of two contrasting cases of adenomatoid odontogenic tumor with unusual presentations

This study aims to report two distinct cases of adenomatoid odontogenic tumor (AOT) with contrasting presentations. The first case involved a 12-year-old female patient with the presence of AOT in the posterior mandible extending into the mandibular ramus up till the coronoid process which is a rare reported site for AOT and the second case is of a 19-year-old male patient with the tumor in the anterior maxilla with an impacted central incisor. Both cases were successfully managed via surgical enucleation and are under regular follow-ups without any complication. The contrasting nature of the two clinical presentations with the same pathologic entity is reported here. Though AOT has been rarely reported extending into the mandibular ramus, a maxillofacial surgeon should be more circumspect of this pathology while dealing with benign swellings of the mandibular posterior region.

Maxillary and mandibular odontogenic myxomas: case report

Maxillary myxomas are rare benign odontogenic tumors with a high potential for infiltration and destruction. Clinical and radiological manifestations are variable and non-specific and often lead to confusion with other benign and malignant lesions. We present here two cases of odontogenic myxoma of different localization (maxilla and mandible). In both cases, the patient presented with a progressively enlarging facial swelling without any neurologic disturbance or lymph nodes. On computed tomography, the lesions appeared as a large unilocular, homogeneous image causing a cortical thinning and rupture along with repression of surrounding tissues. The clinical and radiological features were poorly suggestive of precise nature, and only histological examination of biopsy specimen was able to reveal the diagnosis of myxoma. Given the large size of the tumors and the locally aggressive pattern, we have opted for large maxillecetomy and marginal mandibulectomy. In conclusion, myxoma is a slow growing but locally aggressive tumor that the clinician should keep in mind. As there is a lack of consensus regarding their treatment, we can suggest a conservative treatment for small non-extensive lesions, which consists of enucleation and curettage of the tumor; and a radical excision in case of large tumors given the high risk of recurrence.

Unusual Presentation of Clear Cell Odontogenic Carcinoma: Case Report and Literature Review

Clear cell odontogenic carcinoma (CCOC) is a rare, aggressive epithelial neoplasm of the jaw first described in 1985 by Hansen and classified as an odontogenic malignant tumor in the 2005 WHO classification. To date, only 117 cases have been reported in the literature written in English. In this paper, we report the atypical presentation of a pericoronal localized tumor in the right mandibular wisdom tooth discovered during a routine radiologic examination. The patient, a 44-year-old healthy female, was referred by her general dental practitioner for examination of temporomandibular dysfunction and recurrent myofascial pain. Anamnesis and clinical examination did not suggest tumoral disease. The osteolytic lesion was removed, and histological examination revealed a clear cell odontogenic tumor (CCOT) of the right posterior lower jaw. Segmental lower jaw resection was performed, and a free iliac crest bone transplant was fixed with mandibular reconstruction plate. No cervical neck dissection was needed. A five-year follow-up examination shows excellent local and systemic recovery and no sign of tumor recurrence. The patient still suffers from bruxism and myofascial related pain, which are treated conservatively with a Michigan splint and physiotherapy. Based on this additional case, we review the literature and discuss the challenging diagnostic aspects, the unusual clinical presentation, and the treatment of CCOC.

Compound-complex odontoma: A rare case report

The World Health Organization (WHO) classifies odontomas as odontogenic tumors, consisting of odontogenic epithelium and ectomesenchyme. They result from developmental abnormalities and, therefore, do not constitute authentic tumors. It is a local malformation that has no growth autonomy. They are rarely symptomatic and are usually discovered accidentally during the realization of a radiographic examination. There are two variants of odontomas: complex and compound. Complex odontomas are made of a mass consisting of an anarchic assembly of mineralized tissue (enamel, dentin, and cementum) and dental pulp; while compound odontomas are consisting of a set of small rudimentary teeth, assembling in clusters. They rarely show the features of both types together. The aim of this work is to report a rare presentation of an odontoma in a 24-year-old male patient, which present the characteristics of both complex and compound variants. Surgical excision of the lesion was performed. Anatomopathological examination confirmed the diagnosis. Clinical and radiological survey does not show any recurrence.

Genetic Study of BRAF V600E and SMO L412F Mutations in Japanese Patients with Ameloblastoma

Background and aim: Ameloblastoma is a benign, intraosseous, progressively growing, epithelial, odontogenic neoplasm. BRAF and SMO mutations have been reported in ameloblastoma. In this study, we evaluated BRAF V600E and SMO L412F mutations; and assessed the relationship between BRAF V600E mutant expression and the clinicopathological features in Japanese patients with ameloblastoma. Methods: We examined 24 formalin-fixed paraffin-embedded samples. All specimens were from patients with mandibular ameloblastoma: 20 were conventional ameloblastoma and 4 were unicystic ameloblastoma. The BRAF V600E mutation was assessed by Sanger sequencing and immunohistochemistry, and the SMO L412F mutation was assessed only by Sanger sequencing. Results: Twenty of the 24 (83%) ameloblastoma samples carried the BRAF V600E mutation; 22 of the 24 (92%) samples were immunohistochemically positive for BRAF V600E. However, the SMO L412F mutation was not detected in any of them. The BRAF V600E mutation status did not correlate with the clinicopathological features, such as age, sex, location, method, recurrence, and subtype. Conclusion: BRAF inhibitors could be a potential treatment option for Japanese patients with ameloblastoma, harboring the BRAF V600E mutation.

An unusual case report of basal cell ameloblastoma and a detailed review of literature

Ameloblastoma is an odontogenic tumour derived from the remnants of odontogenic epithelium. Ameloblastoma shows versatile clinical and histological variants. Basal cell ameloblastoma is a rare variant among all histopathological variants of ameloblastoma. We present a case of a 25-year-old male patient with painless swelling on the lower left side of the face for 1 year, which had gradually increased in size and histologically showed features of basal cell ameloblastoma. The aim of the present paper is to understand this rare variant of ameloblastoma and review the literature.

Odontogenic myxoma with pain and uncommon histological feature in the mandible: A case report and review the literature

Odontogenic myxoma (OM) is a rare benign painless, slow-growing lesion with local aggressive behavior. Pain and sensory disturbance and fibro-osseous appearance in histopathology have been rarely reported in OM. The authors reported a 52-year-old male case presented with a large gingival mass around a mobile mandibular right first molar extended to the distal aspect of the third molar. Microscopic examination of the incisional and excisional biopsy revealed an OM with numerous newly formed bone or cementum-like material present throughout the specimen like those seen in fibro-osseous lesions. For avoiding to recurrence, a segmental mandibulectomy was performed and a metal plate was inserted to the right mandible defect under general anesthesia. Rehabilitation was completed with the placement of implants. We review and discuss about this variety.

Adenomatoid odontogenic tumor: a series of 28 cases from a biopsy service

OBJECTIVE

Adenomatoid odontogenic tumor (AOT) is a benign odontogenic tumor with an excellent prognosis, often seen in children and young adults. The aim was to examine the spectrum of clinical, radiographic, and histologic attributes of AOT and assess clinician recognition of this entity. In addition, diagnostic considerations and treatment modalities were explored.

METHOD AND MATERIALS

With Institutional Review Board approval, archival cases of AOT from the University of Florida Oral Pathology Biopsy Service (1994-2019) were examined. Clinical and demographic data along with accompanying radiographs and original slides were reviewed.

RESULTS

A total of 28 cases of AOT were identified. These were all solitary in nature, with a mean age of 20.6 years (range 12-67 years). Most patients were under 20 (75.0%) with a definite female predilection (64.3%). Anterior jaws remained the most common location (85.2%), with a higher maxillary predilection (57.1%). Clinical impression included odontogenic lesions such as dentigerous cyst, lateral periodontal cyst, and odontogenic keratocyst.

CONCLUSION

The spectrum of features of AOT is described. As clinicians were unfamiliar with AOT, highly characteristic features of AOT and more unique variants are discussed extensively to improve diagnostic aptitude. Clinicians must remain aware of this entity, as treatment is minimal compared to other odontogenic entities.

Non-calcifying Langerhans Cell Rich Variant of Calcifying Epithelial Odontogenic Tumor and Amyloid Rich Variant of Central Odontogenic Fibroma: A Unique Entity or a Spectrum?

Overlapping clinicopathological features of non-calcifying Langerhans cell rich variant of calcifying epithelial odontogenic tumor (NCLC-CEOT) and the amyloid rich variant of the central odontogenic fibroma (AR-COF) have been recognized recently. It is still under debate whether these two diseases are indeed one unique disease entity or belong to CEOT and COF, respectively. To clarify this issue, we have performed a literature review to compare the similarities and differences in clinicopathological features among NCLC-CEOT, AR-COF, classic CEOT, and classic COF. We aimed to investigate whether NCLC-CEOT and AR-COF might be the same and one distinctive disease entity, or a variant (or variants) of either CEOT or COF; or whether COF, NCLC-CEOT/AR-COF, and CEOT represented a histopathological spectrum of one disease. Our results indicate that NCLC-CEOT and AR-COF cases share many similar clinicopathological features. Thus, we suggest that they are the same disease entity. Due to nearly no reported recurrence of NCLC-CEOT/AR-COF cases, the conservative surgical treatment is appropriate. The NCLC-CEOT/AR-COF cases show some overlapping clinicopathological features with COF rather than the CEOT cases. However, differences in the clinicopathological features are still recognized among the NCLC-CEOT/AR-COF, COF, and CEOT cases. Future research, particularly molecular biological studies, may further elucidate their relationships and assist proper classification of the NCLC-CEOT/AR-COF cases.

Overview of Radiological Studies on Visualization of Gubernaculum Tracts of Permanent Teeth

The eruption pathway from the dental follicle to the gingiva for permanent teeth is known as the gubernaculum tract (GT), a physiologic structure thought to play a role in tooth eruption. Cone beam computed tomography and multi-detector computed tomography have recently been used to visualize the GT, with the results indicating that this structure might be related to the normal eruption of teeth. By contrast, curved and/or constricted GTs may lead to abnormal tooth eruption. In addition, complex odontomas have been reported from within the GT or dental sac of unerupted permanent teeth. If an odontoma occurs within the GT, the tooth will not erupt normally. Moreover, the imaging characteristics of the GT from the top of the odontogenic mass to the alveolar crest are extremely useful for making a differential pathological diagnosis and for differentiating between odontogenic and non-odontogenic masses. Therefore, radiological studies on the GT have been attracting increasing attention. Given this background, the present review aims to clarify the imaging characteristics and review recent studies on the GT considering the importance of the research.

Compound Odontoma Removed by Endoscopic Intraoral Approach: Case Report

A 12-year-old Japanese boy was referred to our hospital for evaluation of a radiopaque area on the left side of the mandible. Radiographic and computed tomographic examinations revealed a radiopaque lesion located on the lingual side, along with permanent tooth eruption. Several small tooth-like structures were noted within the lesion and the mandibular left second premolar was inclined in a mesial direction. An odontoma was clinically diagnosed and surgical removal by an endoscopic intraoral approach under general anesthesia was planned. Reports of oral surgery using an endoscopic approach have been presented, though none for an odontoma. With the expectation that removal of the odontoma would improve dentition in this case, we planned future management. A minimally invasive surgical removal procedure by an endoscopic intraoral approach from the lingual side was performed and good early recovery was noted. The resected tumor consisted of several small tooth-like structures. Histopathological diagnosis was a compound odontoma. One-year follow-up findings showed that the post-surgical course was good.

Odontogenic Keratocyst in a 9-Month-Old Patient: A Case Report

Odontogenic Keratocyst (OKC) is a benign, intraosseous, odontogenic cyst which originates from the basal cells of overlying epithelium or from the dental lamina remnants. Clinically, they are presented as asymptomatic swellings, although can sometimes be associated with pain. Growth of an OKC leads to expansion and destruction of bone as it infiltrates the tissue around it. It is commonly seen in males between the second and fourth decades of life. The aim of this study is to report on the clinicopathological characteristics of an odontogenic keratocyst in a 9-month-old female patient and posterior rehabilitation with a removable maxillary expander.

Noncalcifying clear-cell variant of calcifying epithelial odontogenic tumor: A case report and review

Clear-cell tumors of the head and neck are biologically diverse consisting of benign, malignant and metastatic lesions. These tumors pose a diagnostic challenge. In the oral cavity, these may be derived from odontogenic/nonodontogenic epithelium or from mesenchyme or can be metastatic. Odontogenic tumors with clear-cell change are rare. Calcifying epithelial odontogenic tumor (CEOT) is a rare, benign, locally aggressive odontogenic epithelial tumor affecting the jaw. Here, we report a case of clear-cell variant of CEOT with its histopathological differential diagnosis. A 43-year-old male patient with swelling in his lower right back tooth region showed a well-defined radiolucent lesion with smooth corticated periphery on radiograph. On incisional biopsy, tumor showed small sheets, cords and islands of odontogenic epithelium with nests of clear cells with no evidence of calcification. A final diagnosis of CEOT was established by differentiating other odontogenic and nonodontogenic lesions on the basis of clinical, radiographic, histopathologic and special stain features.

Cemento-Ossifying Fibroma of Upper Lip in a Female Child

Cemento-ossifying fibroma (COF) is a benign tumor classified under fibro-osseous lesions characterized by the proliferation of fibrous tissue associated with the presence of osteoid or cementicle-like masses. COF of bony origin is highly neoplastic in nature compared to their soft tissue counterparts which are relatively rare. The authors here present a case report of COF arising from the left upper lip in a 10-year-old female patient. The lesion was initially asymptomatic, slow-growing in nature, and later turned painful over a period of eight months. A medical CT was taken to elicit a calcified mass seen at the left subcutaneous plane of the upper lip. The lesion was surgically treated by complete excision under local anaesthesia and sutured. Follow-up was done for a period of one year to assess for recurrence which was not evident in this case. This case report, being a peculiar case of COF arising from the soft tissue of the upper lip, describes the clinical presentation, diagnostic imaging, histopathological evidence, and brief surgical management of the lesion.

Malignant transformation of calcifying epithelial odontogenic tumour with solitary pulmonary metastasis

This report describes the management of a case of calcifying epithelial odontogenic tumour (CEOT) that underwent malignant transformation and metastasized to the lung. The solitary pulmonary metastasis was discovered incidentally on computed tomography (CT) imaging of the neck. It appears that only one previous case with proven pulmonary metastasis has been reported in the literature, which involved multiple pulmonary deposits managed with platinum chemotherapy. The long-term prognosis of metastatic CEOT is therefore unknown. In the case presented here, the patient was managed successfully with surgery alone. There is often diagnostic uncertainty because histological features of benign, recurrent, and malignant CEOT are not dissimilar. Ki-67 immunohistochemistry is helpful, as higher levels are more indicative of malignancy. We consider that in cases of suspected recurrent and malignant CEOT, CT imaging of the thorax and abdomen as part of follow-up may identify metastases early, resulting in earlier treatment, an improved prognosis, and reduced morbidity and mortality.

Odontogenic gingival epithelial hamartoma with a pleomorphic histological appearance: a case report and review of the literature

Odontogenic gingival epithelial hamartoma (OGEH) is a rare odontogenic epitheliallesion. Distinguishing OGEH from peripheral ameloblastoma can pose a differential diagnostic challenge. We report a case of OGEH affecting the lower gingiva in a 78-year-old male patient. The lesion presented as a large, painless, pedunculated mass with a pleomorphic histological appearance. A diagnosis of OGEH was made after the exclusion of peripheral ameloblastoma and peripheral adenomatoid odontogenic tumour. Previous studies have reported differences in sex and age between patients with OGEH and peripheral ameloblastoma; this suggests that peripheral ameloblastoma is not derived from OGEH. Histological findings suggest that the lesions are independent entities.

Identification of circ_0089153/miR-608/EGFR p53 axis in ameloblastoma via MAPK signaling pathway

OBJECTIVES

This study investigated the role of circular RNAs (circRNAs) in the pathogenesis of ameloblastoma (AB), identifying potential novel targets for future targeted therapy.

MATERIALS AND METHODS

CircRNA and microRNA (miRNA) profiling in AB were built with microarrays. Six novel circRNAs were validated, circ-miRNA networks were delineated. Hsa-miR-608 was filtered over cross-comparison between database screening, miRNA microarray and validated. Circ-miRNA binding sponge was validated via luciferase reporter assay. Downstream mRNAs were screened. Regulation between miRNAs and mRNAs was confirmed in vitro. Gene interaction networks and circRNA-miRNA-mRNA interaction pathway enrichment analyses were established.

RESULTS

Six differentially expressed circRNAs were selected and validated. According to miRNAs and pathways predicted, six correlated miRNAs were selected, hsa-miR-608 was filtered and validated. The hsa_circ_0089153/hsa-miR-608 binding sponge was validated. Downstream gene interaction networks showed that EGFR and p53 had the strongest co-expression. In vitro transfection results confirmed the suppressive function of miR-608 and EGFR p53. Hsa_circ_0089153/hsa-miR-608/EGFR p53 interaction pathway enrichment analysis confirmed functions mainly enriched in MAPK and related signaling pathways regulating AB progression.

CONCLUSIONS

Six novel circRNAs were identified. Hsa_circ_0089153/hsa-miR-608 sponging was validated, hsa-miR-608 downregulated EGFR and p53, which might further regulate cell proliferation, differentiation, apoptosis, and cell cycle processes via the MAPK signaling pathway.

Human cytomegalovirus is present in the odontogenic epithelium of ameloblastoma

Background: The factor behind the activation of the remnant odontogenic tissues and development of odontogenic cysts and tumors is poorly understood.This study aimed to investigate the presence of human cytomegalovirus (HCMV) in dentigerous cyst (DC), odontogenic keratocyst (OKC), and ameloblastoma (AB). Methods: The study included 41 samples, which distributed into DC (n=13), OKC (n=12), and AB (n=16). Conventional PCR assay and IHC analysis were used to detect the HCMV-DNA and HCMV glycoprotein B (HCMV-gB) respectively. Results: HCMV-DNA was detected in 10 samples (62.5%) of AB, four samples (30.8%) of DC, and three samples (25 %) of OKC respectively (χ² test = 1.195, p= 0.247). Meanwhile, HCMV-gB was found in 12 (75%) of AB, in 2 (15.4%) of DC, and absent in OKC (0.0%) (χ² test = 4.122, p= 0.042). Conclusions: The high prevalence of HCMV inside the odontogenic epithelium of AB could indicate a possible role of the virus in the oncogenesis and/or oncomodulation of the AB. Additionally, we recommend the IHC for the detection of HCMV in the odontogenic tumors like AB.

Cementoblastoma of a primary molar: A rare pediatric occurrence

Cementoblastoma is a relatively uncommon, benign odontogenic mesenchymal tumor that is associated with and attached to the roots of teeth. It is considered to be the only true neoplasm of cemental origin. Its prevalence has been reported to vary from 0.69% to 8% of all odontogenic tumors. The tumor is frequently seen in the second and third decades of life and affects the molar and premolar regions of the mandible predominantly. We herein describe a case of cementoblastoma occurring in association with primary teeth in a 5-year-old male patient with a brief review of literature. Only 20 cases of cementoblastoma involving primary teeth were found after the English literature search, the current case being the 21^st. Moreover, the deciduous teeth-associated cementoblastomas (14 out of 20) show a distinct predilection for the right side of the face. The current case is the seventh one to involve the left side.

Biological Behavior of Canine Acanthomatous Ameloblastoma Assessed With Computed Tomography and Histopathology: A Comparative Study

Canine acanthomatous ameloblastoma (CAA) appears to have variable biological behavior with some tumors presenting with slow growth and minimal bone loss while others grow rapidly and cause severe cancellous and cortical bone destruction. The primary aim of the study is to elucidate if variations (grades) of CAA can be identified based on both histological and diagnostic imaging indices, and to compare markers of more aggressive behavior between these 2 commonly used diagnostic tools. This study evaluated 45 cases of CAA and confirmed that there is high degree of variability in tumor invasiveness as measured with computed tomography, with predominantly intraosseous tumors being significantly associated with more invasive behavior. However, the analysis also identified that there was very little correlation between computed tomographic and histological appearance of the tumor. CAA tends to have a highly uniform and predictable histological pattern, with tumors that aggressively invade bone (as seen on CT) not showing features of atypia that might be helpful in predicting the biological behavior of the neoplastic cells. Thus, reliance on diagnostic imaging as a measure of biological behavior is recommended for treatment planning as well as possible creation of a variant/grading scheme. Prospective studies are required to evaluate if differing variants of CAA as based on diagnostic imaging should be treated differently, and how this would affect long term clinical outcome.

Adenomatoid odontogenic tumor mimicking a lateral periodontal cyst - A rare case report in the mandible

Adenomatoid odontogenic tumor (AOT) is benign tumor of the oral cavity characterized by its slow growth accounting to 3%-7% of the odontogenic tumors. AOTs mostly occur in the maxillary anterior region and most often than not associated with impacted anterior teeth. It affects the younger age group, especially below 20 years and is commonly seen in females. It occurs as two main variants - (a) central/intraosseous which is more common and (b) peripheral which is rare. The location of the lesion, its association with the impacted tooth, is the basis for the classification of AOT. The intraosseous type may be related to unerupted tooth (follicular variant) or may not be related to unerupted tooth (extra-follicular variant). Radiologically, AOT presents predominantly as a unilocular cystic lesion enclosing the unerupted tooth. The lesion presents rarely with a cystic component. Radiopacities on the intraoral periapical radiograph are seen as discrete foci having a flocculent pattern within radiolucency even with the presence of minimal calcified deposits. AOT being benign in nature is enucleated with least chances of recurrence. Here, we present a rare case of extra-follicular variant of adenomatoid odontogenic tumor in a 19-year-old female patient.

Case Report: Amyloid-Producing Odontogenic Tumor With Pulmonary Metastasis in a Spinone Italiano-Proof of Malignant Potential

A 1-year-old male Spinone Italiano dog was treated for an amyloid-producing odontogenic tumor on the right maxilla with a cytoreductive surgery followed by a definitive radiation protocol. Six years later, the dog presented for a new mass on the rostral mandible as well as a lung nodule without recurrence of the original maxillary tumor. Both the mandibular mass and the lung nodule were histologically confirmed to be amyloid-producing odontogenic tumor based on the appearance of sheets and cords of the odontogenic epithelium disrupted by amorphous extracellular amyloid. This case illustrates the metastatic potential for amyloid-producing odontogenic tumor in dogs and asynchronous occurrence of multiple APOTs in the oral cavity.