It was not possible to detect BRAF V600E mutation in circulating cell-free DNA from patients with ameloblastoma: A diagnostic accuracy study.

BACKGROUND: The objective of this study is to evaluate the diagnostic accuracy of plasma-based liquid biopsy for the detection of the BRAF V600E mutation in circulating cell-free DNA from patients with ameloblastoma. METHODS: This is a prospective diagnostic accuracy study conducted based on the Standards for Reporting Diagnostic Accuracy recommendations. The index test was the plasma-based liquid biopsy, whereas the reference standard was the conventional tissue biopsy. The target condition was the detection of BRAF V600E mutation. The study population consisted of individuals with ameloblastoma recruited from three tertiary hospitals from Brazil. A negative control group composed of three individuals with confirmed wild-type BRAF lesions were included. The participants underwent plasma circulating cell-free DNA and tumor tissue DNA isolation, and both were submitted to using competitive allele-specific TaqMan™ real-time polymerase chain reaction technology mutation detection assays. Sensitivity and specificity measures and positive and negative predictive values were calculated. RESULTS: Twelve patients with conventional ameloblastoma were included. BRAF V600E mutation was detected in 11/12 (91.66%) ameloblastoma tissue samples. However, the mutation was not detected in any of the plasma-based liquid biopsy circulating cell-free DNA samples in both ameloblastomas and negative control group. The sensitivity and specificity of plasma-based liquid biopsy for the detection of the BRAF V600E mutation in circulating cell-free DNA was 0.0 and 1.0, respectively. The agreement between index test and reference standard results was 26.66%. CONCLUSION: Plasma-based liquid biopsy does not seem to be an accurate method for the detection of the BRAF V600E mutation in circulating circulating cell-free DNA from patients with ameloblastoma, regardless of tumor size, anatomic location, recurrence status, and other clinicopathological features.

Rare Case of Recurrent Adamantinoma of the Tibia: Limited Efficacy of Pazopanib as a Standalone Treatment.

BACKGROUND Adamantinoma is a rare low-grade malignant bone tumor, usually found in the tibial diaphysis and metaphysis, with histological similarities to mandibular ameloblastoma. The most effective treatment of recurrent adamantinoma is not yet clear. This report is of a 22-year-old woman with recurrent tibial adamantinoma treated with the tyrosine kinase inhibitor pazopanib. CASE REPORT We report the case of a 22-year-old woman who was referred to our center for a suspicious bone lesion in the right tibia. Bone biopsy findings were consistent with an adamantinoma. En bloc resection was completed successfully, with no postoperative complications. Five years later, a positive emission tomography scan revealed mildly increased tracer uptake near the area of the previous lesion and in the right inguinal lymph node. Biopsies of the lesion and inguinal lymph node confirmed recurrence of the adamantinoma. Due to abdominal and pelvic metastasis, the patient underwent surgical debulking, along with an appendectomy, right salpingo-oophorectomy, intraoperative radiation therapy, and hyperthermic intraperitoneal chemotherapy. Subsequently, the patient was placed on pazopanib for 4 months; however, her tumor continued to worsen after 4 months of chemotherapy. Currently, the patient is receiving gemcitabine and docetaxel as second-line medical therapy. CONCLUSIONS This report showed that pazopanib as standalone treatment does not appear to have promising role on patient outcomes. To the best of our knowledge, this is the second report of pazopanib in the treatment of adamantinoma.

BRAF p.V600E Mutational Status Does Not Correlate with Biological Behavior in Conventional Ameloblastomas: A Disease-Free Survival Analysis.

BACKGROUND: Dysregulation of the MAPK pathway appears to exert a pivotal role in the pathogenesis of ameloblastomas, since BRAF p.V600E has been reported in over 65% of the tumors. Therefore, the purpose of this study was to investigate whether the BRAF p.V600E is related to biological behavior and disease-free survival in patients with conventional ameloblastomas. METHODS: This is a retrospective cohort study based on the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) recommendations. The study population consisted of individuals treated for conventional ameloblastomas. Clinical, imaging, histomorphological, immunohistochemical (Ki67 and CD138/syndecan-1), and molecular BRAF p.V600E mutation analyses were performed. Bivariate statistical analysis was performed through chi-square and Fisher's exact tests. Kaplan-Meier analysis with log-rank test and Cox proportional hazards regression were used to identify predictors of disease-free survival, with a significance level of 5%. RESULTS: Forty-one individuals were included, with a male-to-female ratio of 1.15:1. BRAF p.V600E mutation was identified in 75.6% of the tumors. No association between the BRAF mutational status and other clinical, imaging, histomorphological, and immunohistochemical variables was observed. Only the initial treatment modality was significantly associated with a better prognosis in univariate (p = 0.008) and multivariate (p = 0.030) analyses, with a hazard ratio of 9.60 (95%IC = 1.24-73.89), favoring radical treatment. CONCLUSION: BRAF p.V600E mutation emerges as a prevalent molecular aberration in ameloblastomas. Nevertheless, it does not seem to significantly affect the tumor proliferative activity, CD138/syndecan-1-mediated cell adhesion, or disease-free survival outcomes.

Curettage combined with decompression for the treatment of ameloblastoma in children: report of two cases.

BACKGROUND: Ameloblastoma (AM) is the most common benign odontogenic tumor, which is more often detected in the mandible than maxilla, especially the mandibular body and mandibular angle. Pediatric AM is a rare disease, especially in patients aged 10 and younger. Compared with the mainstream osteotomy and reconstructive surgery for adult ameloblastoma, there is more room for discussion in the treatment of pediatric ameloblastoma. The postoperative functional and psychological influence can not be ignored. Especially for children in the period of growth and development, an osteotomy is often challenging to be accepted by their parents. We report two patients with ameloblastoma under 10 years old who are treated with curettage and fenestration, which is a beneficial method for children with ameloblastoma. CASE PRESENTATION: We present two cases of classic ameloblastoma in children. We describe in detail the patients' characteristics, treatment processes, and follow-up result. The bone formation and reconstruction in the lesion area after fenestration decompression and curettage are recorded at every clinic review. The surgical details and principles of curettage and decompression are also described and discussed. The two patients have good bone shape recovery and no recurrence. CONCLUSIONS: Children are in the growth and development period and possess an extremely strong ability of bone formation and reconstruction. Based on the principles of minimally invasive and functional preservation, we believe that curettage combined with decompression can be the first choice for treating AM in children, especially for mandibular lesions.

METTL1 facilitates ameloblastoma invasive growth via MAPK signaling pathway.

OBJECTIVES: Ameloblastoma (AM), a common odontogenic epithelial tumor, exhibits aggressive growth due to incomplete encapsulation within the jawbone. Postoperative recurrence is a significant concern, closely associated with its invasive nature. We investigate the role of tRNA N-7 methylguanosine (m7G) modification mediated by Methyltransferase-like 1 (METTL1) in AM's invasive growth and prognosis. MATERIALS AND METHODS: METTL1 expression was analyzed in diverse cell lines and clinical AM tissues. Its association with postoperative AM recurrence was examined. Functional experiments included METTL1 gene silencing using shRNA in hTERT-AM cells, assessing cell proliferation, migration, and invasion. Xenograft tumor model was constructed to investigate tumor growth. Molecular mechanisms behind METTL1's role in AM invasiveness were elucidated using Ribosome nascent-chain complex-bound mRNA sequencing (RNC-seq) and experimental analysis. RESULTS: High METTL1 expression was significantly associated with postoperative recurrence in AM. The inhibition of AM development following METTL1 knockdown has been corroborated by experiments conducted both in vitro and in vivo. Analysis of RNC-seq data revealed that downregulated genes were predominantly enriched in the mitogen-activated protein kinase (MAPK) signaling pathway, suggesting that METTL1 may promote AM's invasive growth through the MAPK signaling pathway. CONCLUSION: Our study elucidates the functional role of METTL1 in AM's invasive development and prognosis. High METTL1 expression is linked to postoperative recurrence, and METTL1 appears to promote AM invasiveness through the MAPK signaling pathway. These findings contribute to a better understanding of AM pathogenesis and may guide future therapeutic strategies.

Association of MDM2 Overexpression in Ameloblastomas with MDM2 Amplification and BRAFV600E Expression.

Ameloblastoma is a rare tumor but represents the most common odontogenic neoplasm. It is localized in the jaws and, although it is a benign, slow-growing tumor, it has an aggressive local behavior and high recurrence rate. Therefore, alternative treatment options or complementary to surgery have been evaluated, with the most promising one among them being a targeted therapy with the v-Raf murine sarcoma viral oncogene homologue B (BRAF), as in ameloblastoma the activating mutation V600E in BRAF is common. Studies in other tumors have shown that the synchronous inhibition of BRAF and human murine double minute 2 homologue (MDM2 or HDM2) protein is more effective than BRAF monotherapy, particularly in the presence of wild type p53 (WTp53). To investigate the MDM2 protein expression and gene amplification in ameloblastoma, in association with BRAFV600E and p53 expression. Forty-four cases of ameloblastoma fixed in 10% buffered formalin and embedded in paraffin were examined for MDM2 overexpression and BRAFV600E and p53 expression by immunohistochemistry, and for MDM2 ploidy with fluorescence in situ hybridization. Sixteen of forty-four (36.36%) cases of ameloblastoma showed MDM2 overexpression. Seven of sixteen MDM2-positive ameloblastomas (43.75%) were BRAFV600E positive and fifteen of sixteen MDM2-positive ameloblastomas (93.75%) were p53 negative. All MDM2 overexpressing tumors did not show copy number alterations for MDM2. Overexpression of MDM2 in ameloblastomas is not associated with MDM2 amplification, but most probably with MAPK activation and WTp53 expression. Further verification of those findings could form the basis for the use of MDM2 expression as a marker of MAPK activation in ameloblastomas and the trial of dual BRAF/MDM2 inhibition in the management of MDM2-overexpressing/BRAFV600E-positive/WTp53 ameloblastomas.

Single-cell transcriptomics reveals cell atlas and identifies cycling tumor cells responsible for recurrence in ameloblastoma.

Ameloblastoma is a benign tumor characterized by locally invasive phenotypes, leading to facial bone destruction and a high recurrence rate. However, the mechanisms governing tumor initiation and recurrence are poorly understood. Here, we uncovered cellular landscapes and mechanisms that underlie tumor recurrence in ameloblastoma at single-cell resolution. Our results revealed that ameloblastoma exhibits five tumor subpopulations varying with respect to immune response (IR), bone remodeling (BR), tooth development (TD), epithelial development (ED), and cell cycle (CC) signatures. Of note, we found that CC ameloblastoma cells were endowed with stemness and contributed to tumor recurrence, which was dominated by the EZH2-mediated program. Targeting EZH2 effectively eliminated CC ameloblastoma cells and inhibited tumor growth in ameloblastoma patient-derived organoids. These data described the tumor subpopulation and clarified the identity, function, and regulatory mechanism of CC ameloblastoma cells, providing a potential therapeutic target for ameloblastoma.

Prognostic value of the expression and localization of cell proliferation and apoptosis markers in unicystic ameloblastomas.

The aim of this study was to verify whether the expression of cell proliferation and apoptosis markers in different types of unicystic ameloblastoma (UA) is associated with the location of neoplastic cells. Immunohistochemical study with a sample of 32 cases of UA, 11 cases of conventional ameloblastoma (CAM) and ten dental follicles (DF) cases was performed. Cell proliferation was assessed using Ki-67 status, and apoptosis by caspase-3 expression. Mural UA (MUA) showed a higher immunostaining of Ki-67 (p < 0.05) and a lower immunostaining of Caspase-3 (p < 0.05) compared with luminal and intraluminal subtypes of UA and CAM. The neoplastic cells of the MUA's cystic capsule showed a higher expression of Ki-67 protein (p < 0.0001) and a lower expression of Caspase-3 (p < 0.0001) compared with the lumen. DF showed lower Ki-67 and Caspase-3 immunostaining (p < 0.05) than neoplasms. The higher immunoexpression of Ki-67 and the lower immunoexpression of Caspase-3 in MUA, in the parenchyma cells within the cystic capsule, suggest an association between the biological behaviour and location of neoplastic cells in a tumour.

Advancing Craniopharyngioma Management: A Systematic Review of Current Targeted Therapies and Future Perspectives.

Craniopharyngiomas present unique challenges in surgical management due to their proximity to critical neurovascular structures. This systematic review investigates genetic and immunological markers as potential targets for therapy in craniopharyngiomas, assessing their involvement in tumorigenesis, and their influence on prognosis and treatment strategies. The systematic review adhered to PRISMA guidelines, with a thorough literature search conducted on PubMed, Ovid MED-LINE, and Ovid EMBASE. Employing MeSH terms and Boolean operators, the search focused on craniopharyngiomas, targeted or molecular therapy, and clinical outcomes or adverse events. Inclusion criteria encompassed English language studies, clinical trials (randomized or non-randomized), and investigations into adamantinomatous or papillary craniopharyngiomas. Targeted therapies, either standalone or combined with chemotherapy and/or radiotherapy, were examined if they included clinical outcomes or adverse event analysis. Primary outcomes assessed disease response through follow-up MRI scans, categorizing responses as follows: complete response (CR), near-complete response (NCR), partial response, and stable or progressive disease based on lesion regression percentages. Secondary outcomes included treatment type and duration, as well as adverse events. A total of 891 papers were initially identified, of which 26 studies spanning from 2000 to 2023 were finally included in the review. Two tables highlighted adamantinomatous and papillary craniopharyngiomas, encompassing 7 and 19 studies, respectively. For adamantinomatous craniopharyngiomas, Interferon-2α was the predominant targeted therapy (29%), whereas dabrafenib took precedence (70%) for papillary craniopharyngiomas. Treatment durations varied, ranging from 1.7 to 28 months. Positive responses, including CR or NCR, were observed in both types of craniopharyngiomas (29% CR for adamantinomatous; 32% CR for papillary). Adverse events, such as constitutional symptoms and skin changes, were reported, emphasizing the need for vigilant monitoring and personalized management to enhance treatment tolerability. Overall, the data highlighted a diverse landscape of targeted therapies with encouraging responses and manageable adverse events, underscoring the importance of ongoing research and individualized patient care in the exploration of treatment options for craniopharyngiomas. In the realm of targeted therapies for craniopharyngiomas, tocilizumab and dabrafenib emerged as prominent choices for adamantinomatous and papillary cases, respectively. While adverse events were common, their manageable nature underscored the importance of vigilant monitoring and personalized management. Acknowledging limitations, future research should prioritize larger, well-designed clinical trials and standardized treatment protocols to enhance our understanding of the impact of targeted therapies on craniopharyngioma patients.

Dentigerous cysts suspected the other odontogenic lesions on panoramic radiography and CT.

Dentigerous cysts are known as the second most common type of cyst in the jaws. The cyst is one of the lesions occurred frequently in the posterior body of the mandible and is often related to the unerupted third molar and forms around the crown of the unerupted tooth attaching at the cementoenamel junction. Such characteristic appearances are the diagnostic points differentiating from ameloblastoma or odontogenic keratocyst. However, it would be hard for us to diagnose it as a dentigerous cyst if the lesion does not show its typical appearance. We experienced two cases of dentigerous cysts which did not form around the crown of the unerupted tooth on radiologically. Both cysts were relatively large and resorbed adjacent teeth roots. Therefore, an ameloblastoma or an odontogenic keratocyst was suspected rather than a dentigerous cyst as the imaging diagnosis. The biopsy revealed that the lesion was a "dentigerous cyst" in one of the cases and "developmental cyst with inflammation" in another case. After the excision, the histopathological diagnosis was a dentigerous cyst with inflammation in both cases. This report shows the two cases of dentigerous cysts focusing on panoramic radiography and CT images. Also, we discuss the differential diagnosis by reconsidering those diagnostic points.

Resolution of PTHrP-Mediated Hypercalcemia Following Treatment with Dual BRAF/MEK Inhibition for BRAFV600E-Positive Metastatic Ameloblastoma.

Ameloblastoma is a rare odontogenic tumor which may be complicated by hypercalcemia in advanced disease. Tumoral parathyroid hormone-related peptide (PTHrP) production and local osteolysis from paracrine factors have been proposed as mechanisms. Mitogen-activated protein kinase (MAPK) inhibitors have been successfully used in ameloblastomas with BRAF V600E mutation to reduce symptoms and decrease tumor burden. Serum calcium has been observed to normalize following treatment with MAPK inhibitors; however, the response of PTHrP and markers of bone turnover has not been reported. We describe a case of a 55-year-old female with PTHrP-mediated hypercalcemia secondary to BRAF V600E-positive ameloblastoma with pulmonary metastases. Following treatment with dabrafenib and trametinib, the patient experienced the regression of pulmonary lesions and normalization of serum calcium, PTHrP, and markers of bone turnover. Tissue samples of ameloblastoma carrying BRAF V600E mutation are more likely to express PTHrP than tissue samples carrying wild-type BRAF. In our case, resolution of PTHrP-mediated hypercalcemia following initiation of BRAF/MEK inhibition provides additional evidence that the MAPK pathway contributes to PTHrP synthesis. It also raises the question of whether MAPK inhibitors would be effective in treating PTHrP-mediated hypercalcemia associated with other malignancies harboring BRAF V600E mutation.

DNA content and clinicopathological features aid in distinguishing ameloblastic carcinoma from ameloblastoma.

BACKGROUND: Ameloblastoma and ameloblastic carcinoma are epithelial odontogenic tumors that can be morphologically similar. In the present study, we evaluated the DNA content and Ki-67 index in the two tumors. METHODS: The paraffin blocks of the tumors were selected to obtain sections for the immunohistochemical reactions and preparation of the cell suspension for acquisition in a flow cytometer. The Random Forest package of the R software was used to verify the contribution of each variable to classify lesions into ameloblastoma or ameloblastic carcinoma. RESULTS: Thirty-two ameloblastoma and five ameloblastic carcinoma were included in the study. In our sample, we did not find statistically significant differences in Ki-67 labeling rates. A higher fraction of cells in 2c (G1) was correlated with the diagnosis of ameloblastoma, whereas higher rates of 5c-exceeding rate (5cER) were correlated with ameloblastic carcinoma. The Random Forest model highlighted histopathological findings and parameters of DNA ploidy study as important features for distinguishing ameloblastoma from ameloblastic carcinoma. CONCLUSION: Our findings suggest that the parameters of the DNA ploidy study can be ancillary tools in the classification of ameloblastoma and ameloblastic carcinoma.

Automatic segmentation of ameloblastoma on ct images using deep learning with limited data.

BACKGROUND: Ameloblastoma, a common benign tumor found in the jaw bone, necessitates accurate localization and segmentation for effective diagnosis and treatment. However, the traditional manual segmentation method is plagued with inefficiencies and drawbacks. Hence, the implementation of an AI-based automatic segmentation approach is crucial to enhance clinical diagnosis and treatment procedures. METHODS: We collected CT images from 79 patients diagnosed with ameloblastoma and employed a deep learning neural network model for training and testing purposes. Specifically, we utilized the Mask R-CNN neural network structure and implemented image preprocessing and enhancement techniques. During the testing phase, cross-validation methods were employed for evaluation, and the experimental results were verified using an external validation set. Finally, we obtained an additional dataset comprising 200 CT images of ameloblastoma from a different dental center to evaluate the model's generalization performance. RESULTS: During extensive testing and evaluation, our model successfully demonstrated the capability to automatically segment ameloblastoma. The DICE index achieved an impressive value of 0.874. Moreover, when the IoU threshold ranged from 0.5 to 0.95, the model's AP was 0.741. For a specific IoU threshold of 0.5, the model achieved an AP of 0.914, and for another IoU threshold of 0.75, the AP was 0.826. Our validation using external data confirms the model's strong generalization performance. CONCLUSION: In this study, we successfully applied a neural network model based on deep learning that effectively performs automatic segmentation of ameloblastoma. The proposed method offers notable advantages in terms of efficiency, accuracy, and speed, rendering it a promising tool for clinical diagnosis and treatment.

Transformation of an odontogenic keratocyst into a solid variant of odontogenic keratocyst/keratoameloblastoma during long­term follow­up: A case report.

Keratoameloblastoma (KA) and solid variant of odontogenic keratocyst (SOKC) are rare odontogenic lesions, and their relationship and differences are unclear. The present study described a case that started as an odontogenic keratocyst (OKC) and transformed to SOKC/KA upon recurrence. Briefly, a 26­year­old man presented with swelling in the right cheek and was referred to the Department of Oral and Maxillofacial surgery, Hiroshima University Hospital (Hiroshima, Japan). At the initial visit, unicystic bone permeation was observed extending from the right canine to the molar, maxillary sinus and nasal cavity. After the biopsy, the patient underwent excisional surgery and was diagnosed with OKC. Thereafter, the lesion recurred six times over a period of 13 years and showed different histopathological features from those of the primary lesion, all consisting of numerous cysts with keratinization, which were diagnosed as SOKC/KA. The Ki­67 positivity rate was ~10%, which was higher than that of the primary lesion, but there was no atypia. Genetic analysis of the recurrent lesion revealed mutations in adenomatous polyposis coli and Kirsten rat sarcoma viral oncogene homolog. This case originated from OKC, and the morphological features of OKC and KA were mixed upon recurrence, supporting the commonality and association between the two. However, multiple mutations different from those of OKC and ameloblastoma were detected, suggesting an association of SOKC/KA with increased proliferative activity and a high recurrence rate.

Comparison of diagnostic methods for detection of BRAFV600E mutation in ameloblastoma.

BACKGROUND: Ameloblastoma is an aggressively growing, highly recurrent odontogenic jaw tumor. Its association with BRAFV600E mutation is an indication for BRAFV00E-inhibitor therapy The study objective was to identify a sensitive low-cost test for BRAFV600E-positive ameloblastoma. We hypothesized that immunohistochemical staining of formalin-fixed paraffin-embedded tissues for BRAFV600E mutation is a low-cost surrogate for BRAFV600E gene sequencing when laboratory resources are inadequate for molecular testing. METHODS: Tissues from 40 ameloblastoma samples were retrieved from either formalin-fixed paraffin-embedded blocks, RNAlater™ stabilization solution or samples inadvertently pre-fixed in formalin before transfer to RNAlater™. BRAFV600E mutation was assessed by Direct Sanger sequencing, Amplification Refractory Mutation System-PCR and immunohistochemistry (IHC). RESULTS: BRAFV600E mutation was detected by IHC, Amplification Refractory Mutation System-PCR and Direct Sanger sequencing in 93.33%, 52.5% and 30% of samples respectively. Considering Direct Sanger sequencing as standard BRAFV600E detection method, there was significant difference between the three detection methods (𝜒2 (2) = 31.34, p < 0.0001). Sensitivity and specificity of IHC were 0.8 (95% CI: 0.64-0.90) and 0.9 (95% CI: 0.75-0.99) respectively, while positive predictive value and negative predictive value (NPV) were 0.9 and 0.8 (Fischer's test, p < 0.0001) respectively. Sensitivity and specificity of Amplification Refractory Mutation System-PCR detection method were 0.7 (95% CI: 0.53-0.80) and 0.9 (95% CI = 0.67-0.98) respectively, while PPV and NPV were 0.9 and 0.6 respectively (Fischer's test, p < 0.0001). CONCLUSION: Low-cost and less vulnerability of IHC to tissue quality make it a viable surrogate test for BRAFV600E detection in ameloblastoma. Sequential dual IHC and molecular testing for BRAFV600E will reduce equivocal results that could exclude some patients from BRAFV600E-inhibitor therapies.

Clinicoradiologic features of ameloblastomas: A single-centre study of 155 cases.

BACKGROUND: The purpose of the current study was to report on the clinical presentation and radiologic features of 155 cases of ameloblastoma (AB), representing a detailed, large, single-centre radiologic study. METHODS: Histologically confirmed cases were reviewed over 11 years. Demographic and clinical data were retrieved from the patient's records. Radiologic information was analysed from available radiographs. The radiologic features of ABs were assessed according to the mean age of presentation and the mean duration of the lesion. The distinguishing radiologic features between adults/children and sex were also evaluated. RESULTS: A statistically significant correlation existed between loss of border demarcation and advanced mean age. Multilocular lesions were markedly more common in adults compared to children. Multilocular ABs were associated with increased lesion duration and advanced mean age. Radiologic signs of reactive bony changes associated with the tumour presented at the highest mean duration of all bony effects. Bony expansion and cortical destruction were statistically correlated with lesion duration. Tooth impaction was more common in children. Some mandibular lesions reached a significant size, resulting in impingement of the maxillary sinus, zygoma, orbit and pterygoid plates. CONCLUSION: Due to unfortunate healthcare access constraints, ABs grow to significant sizes and exhibit features not often reported in the literature. The findings of this analysis highlighted the radiologic features of ABs expressed through the mean age and duration of the lesion. This emphasises the significance of timely management of these lesions.

Recurrence and malignant risk of ameloblastoma: A demographic study of 1626 cases from east China.

BACKGROUND: Ameloblastoma is characterized by aggressive nature, high recurrence rate, occasional malignant transformation, but recurrence and malignant incidence of ameloblastoma are not yet addressed by a large-scale case series study. MATERIALS AND METHODS: This study provided a detailed description of the relationship between demographic characteristics and recurrence and malignant cases with different clinical types of ameloblastoma (n = 1626). RESULTS: The overall incidence of recurrence and malignancy was 17.2 % and 3.4 %, respectively. Notably, we observed that there were multiple recurrent episodes (mean time, 24.3-28.7 months) among ameloblastoma patients. Multivariate analysis revealed that age of > 45 years (odds ratios (OR), 2.10; 95 % confidence interval (CI), 1.17-3.76), male (OR, 3.24; 95 %CI, 1.49-6.99), maxilla (OR, 5.58; 95 %CI, 3.11-10.0), and pre-existing recurrence (OR, 3.79; 95 %CI, 2.05-7.01) as independent factors were associated significantly with increased risk of malignancy. CONCLUSION: Identification of the clinical factors responsible for increased risk of malignancy provides better insight in management planning for ameloblastoma.

Differential Profile of Primary and Recurrent Ameloblastomas Among Afro-descendants and Non-Afro-descendants-a Systematic Review.

Ameloblastoma is an aggressively growing jaw tumor with high recurrent properties. Reports on global and racial distribution of ameloblastoma are variable and inconclusive. The role of race and ethnicity on ameloblastoma growth characteristics, genetic mutational profile, and recurrence is also still unclear. The primary aim of this systematic review was to assess genetic, racial, and ethnic distribution of primary and recurrent ameloblastoma from published literature. The secondary aim was to assess potential correlations between ethnicity, genetic mutation, and disparities in ameloblastoma treatment outcomes in Afro-descendants and non-Afro-descendants. Twenty-three eligible articles were selected based on preferred reporting items for systematic review and meta-analysis (PRISMA), and a total of 169 ameloblastoma cases were evaluated. Data on patient demographics, ameloblastoma growth characteristics, and genetic status were collected for quantitative analysis. Among a total of 169 ameloblastoma cases, Afro-descendant patients had higher primary and recurrent ameloblastomas at 15.5% and 4.7% respectively compared to non-Afro-descendant at 10.7% and 1.8% respectively. Additionally, BRAF V600E was positively associated with 48.8% of all ameloblastomas and strong predilection for Afro-descendants. Despite the paucity of information on genetic profile of ameloblastomas in the Afro-descendant patient cohort, this ethnic group still accounted for 2.95% of all BRAF V600E-positive tumors. These suggest that Afro-descendants are understudied regarding ameloblastoma characteristics, genetic profile, and recurrence profile. Mutational analysis of ameloblastoma tumors in Afro-descendants should be promoted.