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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 (𝜒 2 (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., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: Ameloblastoma is an aggressive odontogenic jaw neoplasm. Its unlimited growth confers high potential for malignant transformation and recurrence. It is unclear why ameloblastoma is highly recurrent despite surgical resection with a wide margin of normal tissue. While canonical autophagy can be used to degrade and eliminate damaged cellular components, it is also a protective mechanism that provides energy and vital metabolites for cell survival. We used ameloblastoma-derived cells to test the hypothesis that autophagic processes play a role in survival and reactivation of ameloblastoma., Methods: Primary epithelial (EP-AMCs) and mesenchymal (MS-AMCs) ameloblastoma-derived cells were established from tissue samples of solid multicystic ameloblastoma. Clonogenic capacity and basal autophagic capacity were assessed in ameloblastoma-derived cells relative to human odontoma-derived cells (HODCs) and maxilla-mesenchymal stem cells (MX-MSCs). Ability of ameloblastoma-derived cells to survive and form new ameloblastoma was assessed in mouse tumor xenografts., Results: EP-AMCs were highly clonogenic (p < 0.0001) and demonstrated enhanced basal levels of autophagic proteins microtubule-associated protein 1-light chain 3 (LC3) (p < 0.01), p62 (Sequestosome 1, SQSTM1) (p < 0.01), and the LC3-adapter, melanoregulin (MREG) (p < 0.05) relative to controls. EP-AMCs xenografts regenerated solid ameloblastoma-like tumor with histological features of columnar ameloblast-like cells, loose stellate reticulum-like cells and regions of cystic degeneration characteristic of follicular variant of solid multicystic ameloblastoma. The xenografts also displayed stromal epithelial invaginations strongly reactive to LC3 and p62 suggestive of epithelial-mesenchymal transition and neoplastic odontogenic epithelium., Conclusions: EP-AMCs exhibit altered autophagic processes that can support survival and recurrence of post-surgical ameloblastoma cells., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Purpose: Childhood mandibular lesions are frequently benign; this allows for a conservative surgical approach to their management. Two of the most common approaches for reconstruction of acquired mandibular defects in adolescents are vascularized and nonvascularized osseous flaps or grafts. A third, less commonly used treatment option often used in developing parts of the world that some Western centers are considering as part of their treatment algorithm is spontaneous bone regeneration. This study reports on the authors' experiences with spontaneous bone formation of the resected young mandible. It also attempts to quantify any relation between spontaneous bone regeneration and an aging osteocompetent periosteum., Patients and Methods: This was a retrospective study based on consecutive data collated from records of the oral and maxillofacial surgery departments from 2 tertiary institutions. Eligible patients were no older than 18 years and had benign mandibular neoplasms. The surgical procedure was mandibulectomy with subperiosteal dissection and intermaxillary fixation. Regenerated bone evaluation was by clinical examination and periodic panoramic radiographs., Results: Sixteen consecutive cases with mandibular lesions were seen at the 2 institutions, 8 of which met the inclusion criteria. The average age was 10.75 years. The predominant pathology was unicystic ameloblastoma. All cases exhibited spontaneous bone regeneration, with 2 cases exhibiting "incomplete" bone regeneration., Conclusion: Immediate reconstruction can be delayed to allow for spontaneous bone regeneration of defects in young patients. In the absence of regeneration, secondary reconstruction can be considered. Although the literature reports more young patients with bone regeneration than adults, increasing age during childhood and adolescence might not necessarily indicate a decrease in periosteal bone-regenerating potential., (Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To descriptively review the clinicopathologic presentation and management of ameloblastoma in Nigerian children and adolescents and compare this with previous reports in the literature., Methods and Materials: Data were collected from the case files of patients managed at 4 tertiary referral centers in Nigeria., Results: Out of a total of 360 patients with a diagnosis of ameloblastoma, 79 were under 20 years of age at presentation (21.9%). Only 2.5% of the patients were under 10 years of age. The male-female ratio was 1.3 to 1 with a peak age incidence of 15 years in males and 17 years in females. All the tumors were intraosseous and the majority (94.9%) were situated in the mandible. The most common morphologic type was solid multicystic ameloblastoma (82.3%). The majority (66.2%) had a multilocular radiographic presentation. In most patients (57.3%), the symphysial region of the mandible was involved by the tumor. However, exclusively anterior tumors constituted only 15.2% of the cases, while tumors involving anterior and posterior jaw regions constituted 41.1%. Resection was the predominant (72.2%) form of surgical management., Conclusion: Ameloblastoma in Nigerian children and adolescents exhibit some peculiar clinical features: these include the predominance of males, and of the solid multicystic morphologic type. In addition, there is site predilection for the symphysial region of the mandible. Radical surgical resection remains the predominant form of treatment. Therefore, varying degrees of interference with facial growth will be present in these children.