Malignant Odontogenic Tumours: A Systematic Review of Cases Reported in Literature

Traversing the Terrain: Potential Pitfalls within the AJCC 8th Edition Staging System for Lip and Oral Cavity Cancers

In 1977, the American Joint Committee on Cancer (AJCC) introduced the inaugural Cancer Staging Manual, which implemented the T (tumor extent), N (regional lymph node status), and M (presence or absence of distant metastasis) staging system. This systematic approach aimed to convey the extent of disease across various cancer types, providing clinicians with a practical framework to plan treatment strategies, predict prognosis, and assess outcomes. The AJCC 8th edition, effective from January 1, 2018, continues this tradition. However, certain shortcomings persist in the AJCC 8th edition, as identified through clinical experience. Specifically, challenges arise in accurately assessing depth of invasion in unique histological variants of oral squamous cell carcinoma (e.g., Oral verrucous carcinoma, Carcinoma cuniculatum, and Papillary squamous cell carcinoma) and minor salivary gland tumors. Additionally, discrepancies exist in the perception of bone invasion patterns and in reporting practices. There is also a need for staging guidelines for malignant odontogenic tumors and multifocal tumors of the oral cavity, supplemented by diagrammatic representations. Lastly, there is a call for comprehensive staging criteria for carcinomas of the ear, external auditory canal, and temporal bone. We advocate for the inclusion of these considerations in future editions of the AJCC Cancer Staging Manual.

Wnt/β-catenin-YAP axis in the pathogenesis of primary intraosseous carcinoma NOS, deriving from odontogenic keratocyst

Odontogenic tumors (OGTs), which originate from cells of odontogenic apparatus and their remnants, are rare entities. Primary intraosseous carcinoma NOS (PIOC), is one of the OGTs, but it is even rarer and has a worse prognosis. The precise characteristics of PIOC, especially in immunohistochemical features and its pathogenesis, remain unclear. We characterized a case of PIOC arising from the left mandible, in which histopathological findings showed a transition from the odontogenic keratocyst to the carcinoma. Remarkably, the tumor lesion of this PIOC prominently exhibits malignant attributes, including invasive growth of carcinoma cell infiltration into the bone tissue, an elevated Ki-67 index, and lower signal for CK13 and higher signal for CK17 compared with the non-tumor region, histopathologically and immunohistopathologically. Further immunohistochemical analyses demonstrated increased expression of ADP-ribosylation factor (ARF)-like 4c (ARL4C) (accompanying expression of β-catenin in the nucleus) and yes-associated protein (YAP) in the tumor lesion. On the other hand, YAP was expressed and the expression of ARL4C was hardly detected in the non-tumor region. In addition, quantitative RT-PCR analysis using RNAs and dot blot analysis using genomic DNA showed the activation of Wnt/β-catenin signaling and epigenetic alterations, such as an increase of 5mC levels and a decrease of 5hmC levels, in the tumor lesion. A DNA microarray and a gene set enrichment analysis demonstrated that various types of intracellular signaling would be activated and several kinds of cellular functions would be altered in the pathogenesis of PIOC. Experiments with the GSK-3 inhibitor revealed that β-catenin pathway increased not only mRNA levels of ankyrin repeat domain1 (ANKRD1) but also protein levels of YAP and transcriptional co-activator with PDZ-binding motif (TAZ) in oral squamous cell carcinoma cell lines. These results suggested that further activation of YAP signaling by Wnt/β-catenin signaling may be associated with the pathogenesis of PIOC deriving from odontogenic keratocyst in which YAP signaling is activated.

Exploring gene network and protein interaction analysis of neurotrophin signaling pathway in ameloblastoma

Ameloblastoma is a non-cancerous but aggressive oral tumor emerging from odontogenic epithelial tissue involved during odontogenesis. Since there is lack in unravelling the complete molecular pathogenesis of ameloblastoma, chemotherapy is less attempted and a lot of disagreement over the optimal treatment option. Hence, till date, wide surgical resection is considered to be the reliable treatment for ameloblastoma. The Neurotrophin Signaling pathway plays an important role in neuron signaling and it is closely related with the MAPK pathway, which on the other hand regulated cell differentiation, apoptosis, proliferation, plasticity and survival. Protein- Protein Interaction analysis was analysed with STRING tool using WNL value, identified that CTNNB1, HRAS, NGFR, NGFR, and SORT1 having high interacting with BDNF, NT4, p75NTR, NGF, and NT3. The results of ontology analysis revealed that Neurotrophin signaling pathway is associated with Cell surface receptor signaling pathway, regulation of cell differentiation, regulation of development process, EGFR tyrosine kinase inhibitor resistance, MAPK signaling pathway, PI3K-Akt signaling pathway and Ras signaling pathway leading to pathogenesis involving genes. Further, clustering coefficient values of proteins BDNF, NT4, p75NTR, NGF & NT3 were identified as 0.627, 0.708, 0.367, 0.644 & 0.415. The results of molecular docking studies revealed among the selected ligands Methyl-ɣ-oresellinate, N-(4-Hydroxy-phenyl)-2-phenyl-N-phenylacetyl-acetamide, Atranorin and Oresellinate exhibited high binding affinity with selected protein. The key genes involved in Neurotrophin signaling pathway leading to ameloblastoma pathogenesis is revealed, which are closely associated with cell differentiation, cell proliferation, pro-apoptosis, and pro-survival regulations. Further it can be concluded that Neurotrophin signaling pathway could be one of the promising pathway to tailor the targeted drug therapy for Ameloblastoma treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-024-00223-2.

Ameloblastic Carcinoma in a Young Adult Male Patient - A Case Report

Ameloblastic carcinoma is a rare malignant odontogenic tumor that is further classified into being primary or secondary arising from a preexisting benign ameloblastoma. It affects the mandible in two thirds of the patients. There is no standard treatment protocol for this lesion but radicalsurgical excision with or without radiotherapy is reported in the majority of cases. In this paper, we present a case of a 22 year old male diagnosed with Ameloblastic carcinoma of the mandible with a clinical course of typical aggressiveness and extensive destruction. Histopathological examination of the incised biopsy showed a parakeratinized stratified squamous epithelium with underlying fibrous connective tissue stroma. The stroma is highly myxomatous and exhibits islands of odontogenic epithelium and chronic inflammatory cell infiltrates. Interlacing strands of odontogenic epithelium shows stellate reticulum-like cells and occasional areas of squamous metaplasia with cellular and nuclear pleomorphism. In addition, mitotic figures were noted. With the correlation of clinical, radiographic, and histological features, the lesion is diagnosed as ameloblastic carcinoma. The lesion was surgical excised and post-treatment follow-up for 6 months revealed no recurrence of the malignancy.

Clinico-pathological and prognostic overview of metastasizing ameloblastoma: An overview of the systematic reviews

Background

Metastasizing Ameloblastoma (MA) is an aggressive variant of ameloblastoma (AM) with the ability to metastasize without cytological malignant changes. Thus it aims to comprehensively review the clinico-pathological and prognostic aspects of MA through integration of current literature.

Methods

Electronic searches were conducted in PubMed-MEDLINE, Scopus, Web of Science and Google Scholar. Two independent reviewers screened abstracts and evaluated paper eligibility. AMSTAR2 checklist was used to assessed methodological quality of included systematic reviews (SRs).

Results

From 390 initial papers, 279 underwent eligibility screening, with five systematic reviews (SRs) meeting inclusion criteria. Six hundred sixty-one MA cases were found in five SRs that were included. MA predominantly affects men, exhibits mandible preference, and occurs in individuals in their fourth or fifth decade. Benign metastatic deposits commonly manifest in lungs and lymph nodes. Distant metastasis probability rises with multiple recurrences and incomplete surgical removal. Tumor recurrence and metastasis unfavorably impact clinical outcomes. Quality of evidence assessment was absent across SRs; four SRs were critically low in methodological quality.

Conclusions

AM's metastatic potential lacks predictability. Early/multiple recurrences post-treatment may signal poor prognosis, warranting vigilant follow-up. Methodical analysis of each AM case is imperative to comprehend the metastatic-benign histology relationship.

Odontogenic Carcinosarcoma: Clinicopathologic and Molecular Features of Three Cases, a Literature Review and Nomenclature Proposal

BACKGROUND

Odontogenic carcinosarcoma (OCS) is a rare odontogenic malignancy with limited characterization and unexplored molecular features. We report clinicopathologic and molecular findings in 3 additional OCS and review the literature.

METHODS

3 OCS (5.1%) were identified among 59 malignant odontogenic tumors (in our archives from 1992 to 2022). Clinical, radiologic, histopathologic, immunophenotypic, and molecular findings were reviewed. Data from prior case reports and systematic or non-systematic reviews were extracted for analysis.

RESULTS

Three mandibular OCS (age range: 66 to 72 years; 1 male, 2 females) were identified. Case 1 had novel clear-cell morphology, multiple recurrences, and a lethal outcome 28 months after resection. EWSR1 rearrangements were negative, but the tumor showed focal nuclear β-catenin and strong LEF-1 immunoreactivity. Case 2 demonstrated ameloblastic and sclerosing features and encased the inferior alveolar nerve; the patient was disease-free 22 months after resection with adjuvant chemoradiation therapy. LEF-1 was again strongly positive, and next-generation sequencing demonstrated 9p region-(CDKN2A, CDKN2B) copy number loss, and 12q region-(MDM2, CDK4) copy number gain. Case 3 showed clear-cell and markedly sclerosing features; no follow-up information was available. Literature review along with the current cases yielded 20 cases. OCS showed a male predilection (1.5:1), mandibular predominance (80%, typically posterior), and a bimodal age distribution (modes: 27.7 years, 62.7 years). OCS presented as masses (100%), often with pain (55%), and paresthesia (45%). Tumors were typically radiolucent (88.9%), with bone destruction (61.1%), and/or tooth effacement (27.8%). Preoperative biopsy was sensitive for malignancy (85.7%). At least 45% show evidence for a precursor lesion. 3-year DSS and DFS were 58% and 35%, respectively. Regional and distant (usually lung) metastatic rates were 25% and 31.3%, respectively. Increased mitotic rates and presence of tumor necrosis trended toward worse DSS and DFS.

CONCLUSION

OCS is a rare but aggressive malignancy, often arising from precursor tumors and may represent a terminal phenotype rather than a distinct entity. We describe novel clear-cell and sclerosing morphologies. Wnt pathway alterations appear important. Mitotic rates and necrosis may be adverse prognosticators. In keeping with nomenclature trends in other sites, OCS may be more appropriately designated as "biphasic sarcomatoid odontogenic carcinomas."

Proceedings of the 2023 North American Society of Head and Neck Pathology Companion Meeting, New Orleans, LA, March 12, 2023: Odontogenic Tumors: Have We Achieved an Evidence-Based Classification

BACKGROUND

The World Health Organization's (WHO) chapter on odontogenic and maxillofacial bone tumors provides a global reference for diagnosis of these tumors. In the fifth edition, the inclusion of consensus definitions and development of essential and desirable diagnostic criteria help improve recognition of distinct entities. These are key enhancements since the diagnosis of odontogenic tumors is largely based on histomorphology which is taken in combination with clinical and radiographic appearances.

METHODS

Review.

RESULTS

Despite delineation of diagnostic criteria for ameloblastoma, adenoid ameloblastoma, and dentinogenic ghost cell tumor, a subset of these tumors continues to show overlapping histological features that can potentially lead to misdiagnosis. Accurate classification may be challenging on small biopsies, but potentially enhanced by refining existing diagnostic criteria and utilization of immunohistochemistry and/or molecular techniques in a specific cases. It has become clear that the clinical and histologic features of the non-calcifying Langerhans cell-rich subtype of calcifying epithelial odontogenic tumor and the amyloid-rich variant of odontogenic fibroma converge into a single tumor description. In addition, this tumor shows remarkable clinical, histological overlap with a subset of sclerosing odontogenic carcinoma located in the maxilla. Benign perineural involvement vs perineural invasion is an underexplored concept in odontogenic neoplasia and warrants clarification to reduce diagnostic confusion with sclerosing odontogenic carcinoma.

CONCLUSION

While controversial issues surrounding classification and discrete tumor entities are addressed in the WHO chapter, ambiguities inevitably remain. This review will examine several groups of odontogenic tumors to highlight persistent knowledge gaps, unmet needs and unresolved controversies.

A Current Review of Machine Learning and Deep Learning Models in Oral Cancer Diagnosis: Recent Technologies, Open Challenges, and Future Research Directions

Cancer is a problematic global health issue with an extremely high fatality rate throughout the world. The application of various machine learning techniques that have appeared in the field of cancer diagnosis in recent years has provided meaningful insights into efficient and precise treatment decision-making. Due to rapid advancements in sequencing technologies, the detection of cancer based on gene expression data has improved over the years. Different types of cancer affect different parts of the body in different ways. Cancer that affects the mouth, lip, and upper throat is known as oral cancer, which is the sixth most prevalent form of cancer worldwide. India, Bangladesh, China, the United States, and Pakistan are the top five countries with the highest rates of oral cavity disease and lip cancer. The major causes of oral cancer are excessive use of tobacco and cigarette smoking. Many people’s lives can be saved if oral cancer (OC) can be detected early. Early identification and diagnosis could assist doctors in providing better patient care and effective treatment. OC screening may advance with the implementation of artificial intelligence (AI) techniques. AI can provide assistance to the oncology sector by accurately analyzing a large dataset from several imaging modalities. This review deals with the implementation of AI during the early stages of cancer for the proper detection and treatment of OC. Furthermore, performance evaluations of several DL and ML models have been carried out to show that the DL model can overcome the difficult challenges associated with early cancerous lesions in the mouth. For this review, we have followed the rules recommended for the extension of scoping reviews and meta-analyses (PRISMA-ScR). Examining the reference lists for the chosen articles helped us gather more details on the subject. Additionally, we discussed AI’s drawbacks and its potential use in research on oral cancer. There are methods for reducing risk factors, such as reducing the use of tobacco and alcohol, as well as immunization against HPV infection to avoid oral cancer, or to lessen the burden of the disease. Additionally, officious methods for preventing oral diseases include training programs for doctors and patients as well as facilitating early diagnosis via screening high-risk populations for the disease.

A retrospective case-control study for the comparison of 5-year survival rates: the role of adjuvant and neoadjuvant chemotherapy in craniofacial bone sarcoma in adults

Background

The impact of adjuvant or neoadjuvant chemotherapy in the treatment of craniofacial bone sarcomas has not been clarified. This study aimed to assess whether survival outcomes differed between patients who underwent adjuvant or neoadjuvant chemotherapy.

Methods

A retrospective search for adult patients diagnosed with malignant neoplasms of the craniofacial bones (International Classification of Diseases 10 codes C41.0-C41.1), within the past 20 years from the access date 28 April 2022, was conducted using the TriNetX network (TriNetX, Cambridge, MA, USA). Cohort I included patients who underwent adjuvant chemotherapy and cohort II included patients with neoadjuvant chemotherapy. A refined search for individuals that received common chemotherapeutic agents, such as methotrexate, doxorubicin, cisplatin, and/or ifosfamide, was conducted and patients were assigned to cohort A (adjuvant chemotherapy) and cohort B (neoadjuvant chemotherapy). Following matching for age and sex, Kaplan-Meier analysis was performed, and risk ratio, odds ratio (OR), and hazard ratio were calculated.

Results

Patients were assigned to two cohorts, with 181 patients each after matching. In cohorts I and II, 55 and 41 patients died, respectively. No significant differences were found between the two cohorts regarding the 5-year survival probability (I: 59.87% versus II: 68.45%; p = 0.076; log-rank test), or the risk of dying (I: 0.304 versus II: 0.227; risk difference: 0.077; p = 0.096). The risk analysis before matching for age and sex showed a significant survival benefit in cohort II (OR: 1.586; p = 0.0295; risk difference: 0.093). After a refined query to identify patients treated with methotrexate, doxorubicin, cisplatin, and/or ifosfamide, the two cohorts included 47 patients, respectively. In cohort A (adjuvant chemotherapy), 19 patients died, whereas 12 patients died in cohort B (neoadjuvant chemotherapy) within 5 years after diagnosis. Further analysis indicated a greater survival in cohort B, but the survival probability between the cohorts did not differ significantly (A: 43.55% versus B: 54.49%; p = 0.171).

Conclusion

The use of neoadjuvant chemotherapy may improve survival rates in patients with surgically treated craniofacial bone sarcomas. Due to the retrospective nature of this study, randomized controlled studies are required to derive treatment recommendations.

Desmoplastic Adamantinoma-like Thymic Carcinoma: Clinicopathologic, Immunohistochemical, and Molecular Study of 5 Cases

Five cases of a heretofore unreported rare variant of thymic carcinoma characterized by a striking resemblance to adamantinoma of the mandible are described. The tumors occurred in 4 women and 1 man aged 58 to 76 years (mean: 67.8 y); they arose in the anterior mediastinum and measured from 5.3 to 12.0 cm in greatest diameter (mean: 8.9 cm). Presenting symptoms included chest pain, shortness of breath, and in 2 patients, pleural effusion. One tumor was asymptomatic and discovered incidentally. Histologically, the tumors were extensively desmoplastic, and the cellular proliferation was characterized by multiple islands of squamous epithelium with striking peripheral palisading of nuclei and central areas containing clear cells resembling a stellate reticulum. Areas of preexisting spindle cell thymoma were identified in 2 cases; these areas gradually merged with the higher-grade component of the lesion. Cystic changes were noted in 3 cases. Immunohistochemical studies in 3 cases showed the tumor cells were positive for cytokeratins, p40 and p63, and all showed a high proliferation rate (>50% nuclear positivity) with Ki-67. Next-generation sequencing was performed in 2 cases that showed amplification of the AKT1 gene (copy numbers 6 and 13). Clinical follow-up in 3 patients showed recurrence and metastasis after 1 and 2 years; 1 patient passed away 2 years after diagnosis due to the tumor. Desmoplastic adamantinoma-like thymic carcinoma represents an unusual histologic variant of thymic carcinoma that needs to be distinguished from metastases from similar tumors to the mediastinum.

BRAF V600E Mutation in Ameloblastoma: A Systematic Review and Meta-Analysis

The discovery that ameloblastoma has a high mutation incidence of BRAF V600E may enable a better investigation of pathophysiology. However, there is inconsistent evidence regarding this mutation occurrence and its association with clinical information. This systematic review and meta-analysis aim to pool the overall mutation prevalence of BRAF V600E in reported ameloblastoma cases and to determine its association with patient demographic and clinicopathological features. Following the PRISMA guidelines, a comprehensive article search was conducted through four databases (Scopus, Google Scholar, PubMed, and Web of Science). Seventeen articles between 2014 and 2022 met the inclusion criteria with 833 ameloblastoma cases. For each included study, the significance of BRAF V600E on the outcome parameters was determined using odd ratios and 95% confidence intervals. Meta-analysis prevalence of BRAF V600E in ameloblastoma was 70.49%, and a significant meta-analysis association was reported for those younger than 54 years old and in the mandible. On the contrary, other factors, such as sex, histological variants, and recurrence, were insignificant. As a result of the significant outcome of BRAF V600E mutation in ameloblastoma pathogenesis, targeted therapy formulation can be developed with this handful of evidence.

Primary and secondary ameloblastic carcinoma can be classified into not distinct categories but a single entity: A comparative study

BACKGROUND

Ameloblastic carcinoma (AC) was categorized into primary-type and secondary-type AC by 2005 World Health Organization (WHO) classification, whereas it is reclassified as a single entity in the new WHO classification. However, large sample studies are required to further evaluate and reinforce the classification.

MATERIALS AND METHODS

The clinical behaviors and prognosis of primary AC (n = 25) and secondary AC (n = 24) were comparatively analyzed in a retrospective study of 49 AC patients with a mean follow-up period of 64.5 months.

RESULTS

Differences in all the clinical parameters, including age, gender, tumor site, tumor diameter, teeth involved, maxillary sinus invasion, cranial base invasion, soft tissue invasion, treatment, metastasis, recurrence, and survival status, were not observed between primary and secondary AC groups (all P > 0.05). Cox regression analysis revealed that the association of all the parameters with patients' survival were not significantly different between the two groups, respectively. Consistently, Kaplan-Meier analysis showed that the significant differences in disease-free survival and overall survival were not also observed (P > 0.05).

CONCLUSION

We for the first time addressed that primary-type and secondary-type AC could be classified into not distinct categories but a single entity by a retrospective clinical study.

Managing stage 4 ameloblastoma with dual BRAF/MEK inhibition: A case report with 8-year clinical follow-up

We present 8-year follow-up on the first patient with stage 4 ameloblastoma carrying a BRAF V600E mutation treated with dual BRAF/MEK inhibition (BRAF/MEKi). He experienced a durable clinical response while on dabrafenib (BRAFi) and trametinib (MEKi) without toxicity nor evidence for drug-resistant tumor progression. He was asymptomatic when he self-discontinued therapy after 4 years of sustained clinical response. He did not return for follow-up until 2.5 years later with onset of painful mandibular tumor recurrence associated with recurrent bilateral lung metastases. He was rechallenged with dabrafenib/trametinib and experienced another prompt tumor response and remains in a second durable clinical remission (currently > 16 months) on continuous dual targeted therapy. We discuss the implications of this case study for future treatment strategies.