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Modern Pathology : An Official Journal... Nov 2022Adenoid ameloblastoma is a very rare benign epithelial odontogenic tumor characterized microscopically by epithelium resembling conventional ameloblastoma, with...
Adenoid ameloblastoma is a very rare benign epithelial odontogenic tumor characterized microscopically by epithelium resembling conventional ameloblastoma, with additional duct-like structures, epithelial whorls, and cribriform architecture. Dentinoid deposits, clusters of clear cells, and ghost-cell keratinization may also be present. These tumors do not harbor BRAF or KRAS mutations and their molecular basis appears distinct from conventional ameloblastoma but remains unknown. We assessed CTNNB1 (beta-catenin) exon 3 mutations in a cohort of 11 samples of adenoid ameloblastomas from 9 patients. Two of the 9 patients were female and 7 male and in 7/9 patients the tumors occurred in the maxilla. Tumors of 4 of these 9 patients harbored CTNNB1 mutations, specifically p.Ser33Cys, p.Gly34Arg, and p.Ser37Phe. Notably, for one patient 3 samples were analyzed including the primary tumour and two consecutive recurrences, and results were positive for the mutation in all three tumors. Therefore, 6/11 samples tested positive for the mutation. In the 6 mutation-positive samples, ghost cells were present in only 2/6, indicating beta-catenin mutations are not always revealed by ghost cell formation. Dentinoid matrix deposition was observed in 5/6 mutation-positive samples and clear cells in all 6 cases. None of the cases harbored either BRAF or KRAS mutations. Beta-catenin immunoexpression was assessed in the samples of 8 patients. Except for one wild-type case, all cases showed focal nuclear expression irrespective of the mutational status. Together with the absence of BRAF mutation, the detection of beta-catenin mutation in adenoid ameloblastomas supports its classification as a separate entity, and not as a subtype of ameloblastoma. The presence of this mutation may help in the diagnosis of challenging cases.
Topics: Humans; Male; Female; Ameloblastoma; beta Catenin; Proto-Oncogene Proteins B-raf; Adenoids; Proto-Oncogene Proteins p21(ras); Odontogenic Tumors; Mutation
PubMed: 35840721
DOI: 10.1038/s41379-022-01125-4 -
Journal of Pharmacy & Bioallied Sciences Jul 2023Desmoplastic 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...
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.
PubMed: 37654261
DOI: 10.4103/jpbs.jpbs_44_23 -
Journal of Cancer Research and... 2019Metastasizing ameloblastoma (MA) is a very rare odontogenic tumor with 2% of incidence rate. It exhibits benign histopathological features and malignant intrinsic... (Review)
Review
Metastasizing ameloblastoma (MA) is a very rare odontogenic tumor with 2% of incidence rate. It exhibits benign histopathological features and malignant intrinsic quality in the form of metastasis which makes it a little more than a pathological curiosity. Various molecular aspects related with malignant behavior have been discussed. Because of this, it provides a diagnostic challenge for clinicians and surgeons. It is an elusive lesion which should be more researched and studied so that definitive diagnostic features can be put forward. The objective of this paper is to review the molecular aspect involved in the pathogenesis of MA which will aid in differentiating non-MA from MA and thus helping in providing proper treatment at an early stage.
Topics: Ameloblastoma; Biomarkers, Tumor; Disease Management; Disease Susceptibility; Epithelial-Mesenchymal Transition; Humans; Neoplasm Metastasis; Neoplasm Staging; Tumor Microenvironment
PubMed: 31169204
DOI: 10.4103/jcrt.JCRT_268_17 -
Nigerian Journal of Clinical Practice Sep 2022Ameloblastoma is a benign epithelial odontogenic tumor with a tendency for recurrence. The recurrent tumors behave unpredictably with atypical microscopic changes and...
BACKGROUND
Ameloblastoma is a benign epithelial odontogenic tumor with a tendency for recurrence. The recurrent tumors behave unpredictably with atypical microscopic changes and likelihood of malignant transformation.
AIMS
To study the clinicopathologic features and diagnostic outcome of recurrent tumors of ameloblastoma in Enugu. This is a six-year (2012-2017) retrospective study of 17 consecutive patients with recurrent tumors of ameloblastoma in a Teaching Hospital in Nigeria.
MATERIALS AND METHODS
The relevant clinicopathologic information, histology slides, and blocks were retrieved and reviewed. Descriptive analysis was used to determine the frequency, tables for categorical variables, and a Chi-square test was used to determine the statistical significance.
RESULT
Recurrent tumors constituted 33.3% (17/51) of all confirmed diagnoses of ameloblastoma. The diagnostic outcome of the recurrent tumors was conventional ameloblastoma 58.8% (10), unicystic ameloblastoma 5.9% (1), and ameloblastic carcinoma 35.3% (6). There was bilateral mandibular extension in 60.0% (9), pain 58.8% (10), ulceration 29.4% (5), and matted lymph nodes 5.9% (1). Tumors with positive fluid aspirates 82.4% (14) yielded dark-brown fluids in 90.0% (9) of recurrent ameloblastomas and in 66.7% (2) of ameloblastic carcinomas. Atypical peripheral hyperplasia, nuclear hyperchromatism, and increased vascularization were commonly observed in benign recurrences. The frequency of recurrence is significantly associated with the biological behavior of ameloblastoma P = 0.03.
CONCLUSION
Recurrent tumors of ameloblastoma presented atypical features and malignant transformation.
Topics: Ameloblastoma; Humans; Nigeria; Odontogenic Tumors; Retrospective Studies
PubMed: 36149215
DOI: 10.4103/njcp.njcp_82_22 -
Journal of Clinical and Experimental... Jun 2020Ameloblastoma is a rare tumor which develops from odontogenic epithelium and its remnants and it occurs in the jaws. Peripheral ameloblastomas are rare and benign...
BACKGROUND
Ameloblastoma is a rare tumor which develops from odontogenic epithelium and its remnants and it occurs in the jaws. Peripheral ameloblastomas are rare and benign extraooseous ameloblastomas which effects soft tissues. This case report declares a peripheral ameloblastoma which is a rare type of ameloblastoma.
MATERIAL AND METHODS
34 year old female patient referred with a complaint of a gingival growth at right lower premolar area. A firm and granular surfaced gingival growth with the color of pink and red and having 1.5x1 cm sizes was observed at the mentioned area. With an incision from lower right second incisor tooth to lower right second molar tooth a flap from bone was made and lesion was excised. After then specimen was submitted to histopathologic examination. After clinical, radiological and pathological examinations lesion was described as peripheral ameloblastoma.
RESULTS
At the control examination after three months of excision there was no recurrence and patieant has no complaint.
CONCLUSIONS
Although reccurens rate of peripheral ameloblastomas are low, long-term follow-ups are suggested Patient was informed about the importance of regular controls for early diagnosis of possible reccurenses and regular controls were made during one year after excision. Peripheral ameloblastoma, gingiva, gingival hyperplasia, gingival lesion, alveolar mucosa, extraosseous.
PubMed: 32665822
DOI: 10.4317/jced.56757 -
Journal of Taibah University Medical... Feb 2022This study aims to determine the histopathological patterns and biological characteristics of ameloblastoma.
OBJECTIVES
This study aims to determine the histopathological patterns and biological characteristics of ameloblastoma.
METHODS
This was a cross-sectional retrospective laboratory-based study using 82 formalin-fixed paraffin-embedded tissue blocks from patients diagnosed histologically with ameloblastoma. Information regarding age, sex, anatomical location of the lesion, histopathologic type, and biological behaviour or characteristics of the types of ameloblastoma was obtained from laboratory request forms. Categorical and continuous variables were summarized in percentage and mean ± standard deviation, respectively. The cohort was conducted on Ugandan patients diagnosed between 2016 and 2019.
RESULTS
Most patients (66.3%) were clinically presenting a painless jaw swelling, and a follicular pattern was common (39%) followed by the plexiform pattern (12.2%). All the ameloblastoma cases (100%) were benign, with the majority (76.8%) cases being non-recurrent while the remaining (23.2%) were recurrent, and the plexiform pattern was the commonest recurrent histopathological pattern.
CONCLUSION
This study reports a relatively significant rate of recurrence in almost a quarter of the study population. The plexiform histopathologic type was the dominant type in recurrence cases. Therefore, this finding provides insightful information to clinicians to ensure close follow-up for patients diagnosed with such a variant to prevent possible relapse of the disease.
PubMed: 35140571
DOI: 10.1016/j.jtumed.2021.09.007 -
Cancer Management and Research 2021Ameloblastoma is a benign odontogenic neoplasm with a high local recurrence rate if the operation is not thorough. However, a useful clinical tool for the quantitative...
PURPOSE
Ameloblastoma is a benign odontogenic neoplasm with a high local recurrence rate if the operation is not thorough. However, a useful clinical tool for the quantitative assessment of the prognosis and risk of postoperative recurrence of ameloblastoma has not yet been constructed. This study aims to develop a prognostic nomogram model for ameloblastoma of the jaw to assist surgeons in surgical decision-making.
PATIENTS AND METHODS
Patients who underwent initial surgery for ameloblastoma in our department from October 2004 to March 2020 were enrolled and randomly divided into training and validation sets. Univariate and multivariate Cox proportional hazards regression analyses were performed to identify the independent prognostic factors, from which a nomogram for predicting 3-, 5- and 10-year recurrence-free survival (RFS) of ameloblastoma was constructed using the training set and internally validated using the validation set. The model performance was assessed by Harrell's concordance index (C-index) and calibration curves.
RESULTS
A total of 302 eligible patients with ameloblastoma were enrolled, 54 of whom were confirmed to relapse during the follow-up period of 6 to 191 months. Four independent predictors, including cortical bone perforation, root(s) resorption, WHO classification, and treatment pattern, were identified and included in the construction of a nomogram for recurrence-free survival (RFS), which showed promising calibration performance and discrimination in the training set (C-index 0.790, 95% confidence interval [CI] 0.735-0.845) and the validation set (C-index 0.734, 95% CI 0.599-0.869).
CONCLUSION
A favorable nomogram was developed that accurately predicted the RFS of patients with ameloblastoma based on individual characteristics. Risk stratification using the nomogram could optimize tailored therapy and follow-up.
PubMed: 34103995
DOI: 10.2147/CMAR.S307517 -
Cancer Medicine Apr 2020Ameloblastoma is a rare odontogenic benign tumor accounting for less than 1% of head and neck tumors. Advanced next generation sequencing (NGS) analyses identified high...
Ameloblastoma is a rare odontogenic benign tumor accounting for less than 1% of head and neck tumors. Advanced next generation sequencing (NGS) analyses identified high frequency of BRAF V600E and SMO L412F mutations in ameloblastoma. Despite the existence of whole genomic sequence information from patients with ameloblastoma, entire molecular signature of and the characteristics of ameloblastoma cells are still obscure. In this study, we sought to uncover the molecular basis of ameloblastoma and to determine the cellular phenotype of ameloblastoma cells with BRAF mutations. Our comparative cDNA microarray analysis and gene set enrichment analysis (GSEA) showed that ameloblastoma exhibited a distinct gene expression pattern from the normal tissues: KRAS-responsive gene set is significantly activated in ameloblastoma. Importantly, insulin like growth factor 2 (IGF2), a member of KRAS-responsive genes, enhances the proliferation of an ameloblastoma cell line AMU-AM1 with BRAF mutation. In addition, Toll-like receptor 2 (TLR2) knockdown readily inactivated KRAS-responsive gene sets as well as increases caspase activities, suggesting that TLR2 signaling may mediate cell survival signaling in ameloblastoma cells. Collectively, the findings may help to further clarify the pathophysiology of ameloblastoma and lead to the development of precision medicine for patients with ameloblastoma.
Topics: Adult; Aged; Ameloblastoma; Biomarkers, Tumor; Cell Proliferation; Child; Female; Follow-Up Studies; Gene Expression Regulation, Neoplastic; Humans; Jaw Neoplasms; Male; Middle Aged; Mutation; NF-kappa B; Prognosis; Toll-Like Receptor 2; Transcriptome; Tumor Cells, Cultured
PubMed: 32096304
DOI: 10.1002/cam4.2931 -
Frontiers in Veterinary Science 2022Ameloblastoma is a benign epithelial odontogenic tumor with the capacity to aggressively invade the surrounding bone. Surgical removal of the tumor can result in... (Review)
Review
Ameloblastoma is a benign epithelial odontogenic tumor with the capacity to aggressively invade the surrounding bone. Surgical removal of the tumor can result in extended disease-free interval (cure). However, controversy surrounds the most appropriate surgical margin required to prevent local recurrence while simultaneously minimizing morbidity. excisional surgery carries the risk of major complications such as mandibular drift, hemorrhage, and oronasal fistula formation. Conservative therapy without a safety margin reduces potential morbidity but is likely to result in local recurrence. No reliable rate, nor time to recurrence, is documented but may be as high as 91% with conservative therapy. Conversely, surgery with a 10- to 20-mm margin is associated with a 0-4.6% recurrence rate. There is no documented difference in the recurrence rate with a 10- vs. 20-mm margin. The correlation of the histologic margin with the recurrence rate following excisional surgery has not determined a required histologic safety margin. Rather, no local recurrence occurs despite narrow or incomplete margins. Thus, pathologic margins > 0 mm may be sufficient to prevent local recurrence or recurrence may be protracted. Accordingly, a narrow (5-10 mm) gross surgical margin may be the most appropriate. Additional research is required for confirmation, and only level 4 evidence on safety margins has been achieved thus far. Future work should focus on defining the extension of neoplastic cells past the demarcation of ameloblastoma on variable diagnostic imaging modalities as well as determining the recurrence rate with various surgical and histologic safety margins.
PubMed: 35392113
DOI: 10.3389/fvets.2022.830258 -
Indian Journal of Otolaryngology and... Oct 2022Ameloblastoma is a locally aggressive benign neoplasm of jaw that has high propensity to recur. Pathological subtype and intent of surgical excision during primary...
Ameloblastoma is a locally aggressive benign neoplasm of jaw that has high propensity to recur. Pathological subtype and intent of surgical excision during primary surgery are two factors that are known to affect the prognosis in these cases. Nevertheless, there are hardly any studies which have studied recurrent ameloblastoma cases. Apart from sharing a tertiary care cancer center's experience in managing a series of recurrent ameloblastoma cases, we discuss some of the recent literature related to pathophysiology and principles related to their surgical management. Retrospective chart review of all those recurrent ameloblastoma cases which were operated between October 2013 and January 2016 and were subsequently followed up for minimum of 3 years. Total of 9 recurrent ameloblastoma cases were operated in the study period. All our patients had less-radical or non-curative intent surgical treatment in the past, and current treatment consisted wide excision of the involved segment of mandible with free fibular reconstruction. Among the 6 patients who were followed up for more than 3 years, none developed recurrence at 56.5 months of mean follow up duration. Almost all these patients had optimal results with good quality of life in terms of oral speech intellectuality and cosmetic perception of self. Complete excision of the involved segment of bone with reconstruction using the composite free fibular graft can provide optimal functional outcomes and can significantly lessen the chances of further recurrences.
PubMed: 36452534
DOI: 10.1007/s12070-020-01790-4