-
Turk Patoloji Dergisi 2022The 5th edition of the World Health Organization (WHO) Classification of Head and Neck Tumors opened to online access in March 2022. This edition is conceptually similar... (Review)
Review
The 5th edition of the World Health Organization (WHO) Classification of Head and Neck Tumors opened to online access in March 2022. This edition is conceptually similar to the previous classification of odontogenic lesions. The only newly defined entity in odontogenic lesions is adenoid ameloblastoma, which is classified under benign epithelial odontogenic tumors. While not odontogenic, the surgical ciliated cyst is a new entry to the cyst classification of the jaws. In other respects, a very important change was made in the new blue books that added 'essential and desirable diagnostic criteria' for each entity to highlight the features considered indispensable for diagnosis. In this article, we review the odontogenic tumors and cysts of the jaw sections of the Odontogenic and Maxillofacial Bone Tumors Chapter, outlining changes from the 2017 WHO classification and summarizing the essential diagnostic criteria and new developments.
Topics: Ameloblastoma; Head and Neck Neoplasms; Humans; Odontogenic Cysts; Odontogenic Tumors; World Health Organization
PubMed: 35578902
DOI: 10.5146/tjpath.2022.01573 -
Cureus Aug 2022Ameloblastoma is one of the most common benign odontogenic tumors of the jaw that constitutes about 10% of all tumors that arise in the mandible and maxilla. It is a... (Review)
Review
Ameloblastoma is one of the most common benign odontogenic tumors of the jaw that constitutes about 10% of all tumors that arise in the mandible and maxilla. It is a slow-growing but locally invasive tumor that presents with painless swelling of the mandible or maxilla. The World Health Organization (WHO) classification of 2017 describes ameloblastomas of the following four types: ameloblastoma; unicystic ameloblastoma; extraosseous/peripheral ameloblastoma; and metastasizing ameloblastoma. The diagnosis of ameloblastoma requires computerized tomography (CT) imaging as well as a biopsy. A biopsy is helpful in differentiating ameloblastoma from ossifying fibroma, osteomyelitis, giant cell tumor, cystic fibrous dysplasia, myeloma, and sarcoma. The best treatment of ameloblastoma is aggressive en bloc resection with simultaneous reconstruction. The high recurrence rate and large tissue defects have been long-standing issues in the treatment of ameloblastoma. Recent molecular developments strongly suggest the possibility of targeted therapy with better outcomes in ameloblastomas. We present a detailed updated narrative review of our current understanding and management of this enigmatic tumor.
PubMed: 36127985
DOI: 10.7759/cureus.27734 -
JNMA; Journal of the Nepal Medical... Jul 2022Ameloblastomas of jaws are benign odontogenic tumors of epithelial origin with four clinical variants: solid multicystic type, unicystic type, desmoplastic type, and...
UNLABELLED
Ameloblastomas of jaws are benign odontogenic tumors of epithelial origin with four clinical variants: solid multicystic type, unicystic type, desmoplastic type, and extraosseous type. The incidence rate of ameloblastoma is 0.92 per million person-years. Unicystic ameloblastoma refers to those cystic lesions that show clinical and radiologic characteristics of an odontogenic cyst but shows a typical ameloblastomatous epithelium lining part of the cyst cavity, with or without luminal and/or mural tumor proliferation on histological examination. Here is a unique case of unicystic ameloblastoma involving the mandible in a 70-year-old patient. The case was managed by segmental mandibulectomy and flap repair. Unicystic ameloblastoma accounts for only 13% of all known cases in scientific literature. Considering the rarity of the lesion, the purpose of presenting this report on a clinical case is to emphasize the importance of radiological evaluation and histopathological examination for the diagnosis of ameloblastoma.
KEYWORDS
ameloblastoma; odontogenic cysts; odontogenic tumors; segmental mandibulectomy.
Topics: Humans; Aged; Ameloblastoma; Mandible; Odontogenic Tumors; Odontogenic Cysts; Jaw
PubMed: 36705195
DOI: 10.31729/jnma.7566 -
The American Journal of Case Reports Jul 2015Ameloblastic carcinoma secondary type is an extremely rare and aggressive odontogenic neoplasm that exhibits histological features of malignancy in primary and...
BACKGROUND
Ameloblastic carcinoma secondary type is an extremely rare and aggressive odontogenic neoplasm that exhibits histological features of malignancy in primary and metastatic sites. It arises through carcinomatous de-differentiation of a pre-existing ameloblastoma or odontogenic cyst, typically following repeated treatments and recurrences of the benign precursor neoplasm. Identification of an ameloblastic carcinoma, secondary type presenting with histologic features of malignant transformation from an earlier untreated benign lesion remains a rarity. Herein, we report 1 such case.
CASE REPORT
A 66-year-old man was referred for management of a newly diagnosed ameloblastic carcinoma. He underwent radical surgical intervention comprising hemimandibulectomy, supraomohyoid neck dissection, and free-flap reconstruction. Final histologic analysis demonstrated features suggestive of carcinomatous de-differentiation for a consensus diagnosis of ameloblastic carcinoma, secondary type (de-differentiated) intraosseous.
CONCLUSIONS
Ameloblastic carcinoma, secondary type represents a rare and challenging histologic diagnosis. Radical surgical resection with adequate hard and soft tissue margins is essential for curative management of localized disease.
Topics: Aged; Ameloblastoma; Biopsy; Diagnosis, Differential; Humans; Lymphatic Metastasis; Male; Mandibular Neoplasms; Mandibular Osteotomy; Neck Dissection; Radiography, Panoramic
PubMed: 26126621
DOI: 10.12659/AJCR.893918 -
Pathologie (Heidelberg, Germany) Aug 2022Odontogenic tumors (OTs) are rare, with an estimated incidence rate of less than 0.5 cases per 100,000 per year. The causes of OTs remain unclear. Nonetheless, the... (Review)
Review
BACKGROUND
Odontogenic tumors (OTs) are rare, with an estimated incidence rate of less than 0.5 cases per 100,000 per year. The causes of OTs remain unclear. Nonetheless, the majority of OTs seem to arise de novo, without an apparent causative factor. Although the etiopathogenesis of most OTs remains unclear, there have been some recent advances in understanding the genetic basis relating to specific histologies and clinical features. Molecular analyses performed by different techniques, including Sanger sequencing, next-generation sequencing, and allele-specific PCR, have uncovered mutations in genes related to the oncogenic MAPK/ERK signaling pathway. Genetic mutations in these pathway genes have been reported in epithelial and mixed OTs, in addition to odontogenic carcinomas and sarcomas. Notably, B‑RAF proto-oncogene serine/threonine kinase (BRAF) and KRAS proto-oncogene GTPase (KRAS) pathogenic mutations have been reported in a high proportion of ameloblastoma and ameloblastoma-related tumors and adenomatoid odontogenic tumors, respectively.
OBJECTIVE
To discuss how molecular profiling aids in diagnostic classification of odontogenic tumors.
CONCLUSION
Molecular profiling of odontogenic tumors helps to identify patients for neoadjuvant therapies and reduces postoperative morbidity.
Topics: Humans; Ameloblastoma; Odontogenic Tumors; Pathology, Molecular; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins p21(ras)
PubMed: 36378285
DOI: 10.1007/s00292-022-01152-7 -
Archives of Oral Biology Aug 2022This article aims to systematically and comprehensively discuss molecular biology-related progress and targeted therapeutic strategies for ameloblastoma, which are... (Review)
Review
OBJECTIVE
This article aims to systematically and comprehensively discuss molecular biology-related progress and targeted therapeutic strategies for ameloblastoma, which are expected to be helpful for the diagnosis and treatment of ameloblastoma.
DESIGN
A comprehensive review of scientific literature relevant to ameloblastoma, including the latest classification, global epidemiology, molecular biology advances, and targeted therapy.
RESULTS
Among the 156 articles cited, a total of 20 non-coding RNAs, 13 genes, 27 proteins, and 8 pathways were involved, which play a variety of roles in ameloblastoma. These roles include participation in the biological behaviours of ameloblastoma migration, differentiation, and apoptosis; detection of ameloblastoma proliferative properties; detection of ameloblastoma angiogenesis; and identification of ameloblastoma carcinogenesis.
CONCLUSIONS
At present, some progress has been made in molecular biology and targeted therapy for ameloblastoma involving BRAF and SMO genes. The related non-coding RNAs, genes, proteins, and pathways involved in this review provide new ideas and directions for the occurrence and development of ameloblastoma and have the potential to become new gene therapy targets.
Topics: Ameloblastoma; Humans; Molecular Biology; Mutation; Proto-Oncogene Proteins B-raf
PubMed: 35597128
DOI: 10.1016/j.archoralbio.2022.105454 -
Frontiers in Oral Health 2021DNA methyltransferases (DNMTs) and the histone modification H3K9ac are epigenetic markers. This study aimed to describe the immunohistochemical expression of DNMT1,...
DNA methyltransferases (DNMTs) and the histone modification H3K9ac are epigenetic markers. This study aimed to describe the immunohistochemical expression of DNMT1, DNMT3A, DNMT3B, and H3K9ac in the dental follicle (DF), ameloblastoma (AME), and ameloblastic carcinoma (AC), correlating these expressions with the recurrence and aggressive behavior in ameloblastoma. Immunohistochemical reactions were performed in 10 human DFs, 38 ameloblastomas, and 6 AC samples. Another 59 ameloblastomas assembled in a tissue microarray were used to compare the immunoexpression with the clinical, radiographic, and histopathological characteristics and the presence of BRAFv600e mutation. Each slide was digitized as a high-resolution image and quantified by Aperio ScanScope Nuclear V9 software. All statistical analyzes were performed using GraphPad Prism statistical software. DNMT3B expression was higher in ameloblastomas than in the DFs, while the AC overexpressed all proteins. The ameloblastomas with BRAFv600e mutation, vestibular/lingual, or vestibular/palatine bone cortical disruption and maxilla involvement showed DNMT1 overexpression, while recurrent cases had high DNMT3B levels. DNA methylation and histone modification might play a role in the development, clinical aggressiveness, and recurrence rates of ameloblastoma, such as the progression to AC. Further investigation about gene methylations in ameloblastomas is needed to better understand its relationship with aggressiveness and recurrence.
PubMed: 35048062
DOI: 10.3389/froh.2021.751162 -
Sultan Qaboos University Medical Journal Aug 2022This article aimed to collectively present the demographic, clinical, radiographic and histopathological features as well as the treatment performed along with its... (Review)
Review
This article aimed to collectively present the demographic, clinical, radiographic and histopathological features as well as the treatment performed along with its outcome for all the cases of adenoid ameloblastoma with dentinoid (AAD) reported in scientific literature till date. Ameloblastoma and adenomatoid odontogenic tumours are the most common odontogenic neoplasms. However, AAD, a hybrid variant of the two lesions, is found to be extremely rare. The lesion comprises of characteristic histopathological features of ameloblastoma and adenomatoid odontogenic tumour and shares certain clinical characteristics with either of the entities. AAD may be considered to be present at the more aggressive end of spectrum of benign odontogenic neoplasms. Owing to the frequent tendency of the lesions to be underdiagnosed, careful histopathological screening of submitted biopsies is warranted. With the increase in number of reported cases in the recent years, it is likely to be included as a separate entity in the upcoming World Health Organization classification.
Topics: Adenoids; Ameloblastoma; Biopsy; Humans; Odontogenic Tumors
PubMed: 36072074
DOI: 10.18295/squmj.9.2021.127 -
Journal of Clinical and Experimental... Mar 2021Ameloblastoma is a locally aggressive tumor, originated from odontogenic epithelium, and affects the jawbones with an elevated recurrence rate. The molecular mechanisms... (Review)
Review
BACKGROUND
Ameloblastoma is a locally aggressive tumor, originated from odontogenic epithelium, and affects the jawbones with an elevated recurrence rate. The molecular mechanisms involved with the pathogenesis of this tumor remain undetermined. This review aimed to describe the current data regarding epigenetic alterations in ameloblastoma.
MATERIAL AND METHODS
A systematized electronic search was performed in the English-language literature in three databases, combining the following keywords: ameloblastoma, epigenetic, methylation, noncoding RNA, histone acetylation.
RESULTS
According to the gathered results of 11 studies in this review, epigenetic alterations could induce the development and progression of ameloblastoma. DNA methylation has been the most assessed mechanism in ameloblastomas.
CONCLUSIONS
Current literature data indicate that epigenetic events can be involved in the etiopathogenesis of ameloblastomas. Ameloblastoma, epigenetic, methylation, noncoding RNA, histone acetylation.
PubMed: 33680332
DOI: 10.4317/jced.56191 -
Indian Journal of Dental Research :... 2022Ameloblastoma is a benign, locally aggressive neoplasm that needs extensive surgical resection. The goal of this article is to obtain an in-depth review of benign... (Review)
Review
Ameloblastoma is a benign, locally aggressive neoplasm that needs extensive surgical resection. The goal of this article is to obtain an in-depth review of benign ameloblastomas to determine the available level of evidence and the possible benefit of targeted therapeutics for the treatment of ameloblastoma and BRAF V600E mutation in ameloblastoma. An electronic literature search was conducted according to PRISMA guidelines in PubMed/MEDLINE, EBSCO, and Web of Science for eligible studies published between 1975 and 2021. The systematic review is registered with INPLASY (INPLASY202260018). The review included 2 case series and 17 case reports. The histopathological type, anatomic location, expression of BRAF mutation, additional mutations, and molecular-targeted therapies of the 19 reviewed articles were summarized and tabulated. Interestingly, the majority of the primary site of ameloblastoma was located in the mandible (80.9%) compared to the maxilla (17%). The tumour size was reported in nine of the included studies. Most of the included studies in the review exhibited ameloblastoma with BRAF V600E mutations and responded to molecular-targeted therapies. Molecular therapies employing BRAF and/or MEK inhibitors in ameloblastoma with BRAF V600E mutations proved to be an appropriate treatment based on the limited available evidence. It is essential further to deepen our understanding at the clinical and molecular level to enhance the precision of management of ameloblastoma.
Topics: Humans; Ameloblastoma; Molecular Targeted Therapy; Mutation; Proto-Oncogene Proteins B-raf
PubMed: 36656197
DOI: 10.4103/ijdr.ijdr_456_22