Unicystic Ameloblastoma Research Articles

Immunohistochemical Expression of MDM2, Bcl-2, SATB2 and Ki-67 in Histological Variants of Unicystic Ameloblastoma.

To characterize the immunohistochemical expression of MDM2, Bcl-2, SATB2 and Ki-67 in histological variants of unicystic ameloblastoma (UA). Following the ethical approval, forty (40) patients with unicystic ameloblastoma were retrieved from the archives and subjected to immunohistochemistry (IHC). Sociodemographic and clinical data were also retrieved. The results were entered into a Microsoft Excel spreadsheet and analyzed using SPSS software. Human tooth germs, which served as the control, showed moderate expression of Bcl-2 and MDM2 with slight proliferative activity in ameloblasts and moderate expression of SATB2 in ectomesenchyme and odontoblasts. Luminal UA (Type 1) showed low Ki-67 index and negative to mild Bcl-2 and MDM2 expression, whilst Type 1.2 (luminal and intraluminal), Type 1.2.3 (luminal, intraluminal and mural), and Type 1.3 (luminal and mural), including the recurrent cases, showed moderate to intense expression with high mean Ki-67 index. The difference between the study groups was statistically significant (p value < 0.001). No expression of SATB2 was noted in any histological variant of UA. Furthermore, no significant differences were noted in age, gender, site and location between the groups. In contrast to luminal variant of UA, mural±intraluminal variants and recurrent cases demonstrate higher expression of Bcl-2 and MDM2 with higher mean Ki-67 index. It may thus be prudent to provide aggressive treatment for cases, not just with mural follicles but also for the patients with intraluminal plexiform proliferation, to prevent recurrence and improve patient outcomes.

Enucleation of a unicystic ameloblastoma associated with tooth autotransplantation

Enucleation of a unicystic ameloblastoma associated with tooth autotransplantation

BRCA1/2 Immunohistochemical Analysis in Unicystic Ameloblastoma, Multicystic Ameloblastoma, and Ameloblastic Carcinoma

Background: Lesions arising from odontogenic tissues cover a wide spectrum, from simple cysts to benign tumors and even carcinomas. Unicystic ameloblastoma (UA), multicystic ameloblastoma (MA), and ameloblastic carcinoma (AC) are relatively common among these odontogenic lesions. Nevertheless, the exact origin of these lesions remains unclear. It is noteworthy that BRCA1/2 mutations have been identified as potential contributing factors to the onset of various cancers. The aim of the current study was to scrutinize the BRCA1/2 expression profiles in UA, MA, and AC samples. Methods: Biopsy specimens were collected from 60 patients, with 20 samples representing each lesion, sourced from the pathology department archive of a teaching hospital from 2000 to 2019. Immunohistochemical staining was conducted on all biopsy samples. Statistical analyses were performed using the Kruskal-Wallis H test. The differences in the data were compared with Mann- Whitney U test, and P&lt;0.05 was considered to be significant. Results: The Kruskal-Wallis test results revealed significant differences between the examined samples in terms of the cytoplasmic expression level of the BRCA1 basal cells (P&lt;0.001). Regarding the cytoplasmic expression of BRCA1 stellate reticulum-like cells, there was a statistically significant difference between the examined groups (P&lt;0.001). Furthermore, the results of the Kruskal-Wallis test demonstrated a significant difference concerning the cytoplasmic expression levels of BRCA2 basal cells between the studied groups (P&lt;0.003). Based on the Kruskal-Wallis results, significant differences were found in terms of the cytoplasmic expression level of BRCA2 stellate reticulum-like cells between the investigated samples (P&lt;0.001). The Mann-Whitney U test compared differences between the two examined groups. Conclusion: The findings mainly revealed the expression of BRCA1/2 at the invasive front, which is composed of the most aggressive cells. Molecular interactions in this area may affect tumor progression. BRCA1/2 mutations can be a promising future treatment option for ameloblastoma and related lesions.

Unicystic Ameloblastoma Masquerading as Vascular Lesion

Ameloblastoma is a benign epithelial tumor of odontogenic origin which shows variations in its presentation that intrigue the authors. Authors report a case of unicystic ameloblastoma which presented, clinically and radiographically mimicking features of a vascular lesion. Patient reported with the chief complaint of pain and swelling in the left lower-third of the face. The investigations performed gave a diagnosis dilemma and hence deciding on appropriate investigations played a pivotal role to enable precise diagnosis of the lesion and facilitated surgeons to decide on the treatment plan.

MMP13 Expression and Activity Suggest Its Role in Bone Resorption in Ameloblastomas.

Ameloblastoma is a locally destructive benign odontogenic tumor. While the neoplastic cells of conventional ameloblastoma can infiltrate the connective tissue and bone, in unicystic ameloblastoma the epithelium is encapsulated. The mechanisms driving ameloblastoma's bone resorption remains unclear. RNA sequencing (RNA-seq) was performed in a discovery cohort of conventional ameloblastoma, and pathway enrichment analysis was carried out. mRNA levels of MMP13, a gene associated with bone resorption, were assessed using RT-qPCR in a larger cohort of conventional ameloblastoma and in unicystic ameloblastoma. Zymogram gels and the immunoexpression profile of collagenase 3 (encoded by MMP13 gene) were evaluated as well. Enriched pathways related to bone mineralization and upregulation of MMP13 were observed in ameloblastomas. Collagenolytic activity of collagenase 3 was detected in the tumor lysates. Collagenase 3 immunopositivity was observed in ameloblastomatous epithelium infiltrating the fibrous capsule of unicystic ameloblastoma. At the tumor-bone interface, collagenase 3 expression was detected in stromal cells, osteoblasts, and osteocytes. The results indicate a potential involvement of MMP13 in ameloblastoma-related bone resorption and progression.

Plexiform Variant of Ameloblastoma in Body of Mandible: Case Report and Review of Literature

Ameloblastoma is a benign but locally aggressive odontogenic epithelial neoplasm arising from remnants of dental lamina and dental organ [1,4]. This neoplasm is more prevalent between 2nd to 4th decade of life and mandible (11%) is more commonly involved than maxilla (1%) [2,5]. It has an aggressive behavior and recurrent course, It is rarely metastatic. Ameloblastoma represents 10% of odontogenic tumors and 1% of all tumors and cysts involving the maxillo mandibular region [1]. The World Health Organization (WHO) classification of 2017 describes ameloblastomas of the following four types: Solid/multicystic ameloblastoma (91%) unicystic ameloblastoma (6%); extraosseous/peripheral ameloblastoma (2%); and metastasizing ameloblastoma (1%). [3,8] A conclusive diagnosis can only be made by histopathology because it has wide range of histologic patterns and has radiographic characteristics with other lesions such the odontogenic keratocyst, giant cell tumour, aneurysmal bone cyst, and renal cell carcinoma metastasis.[5] Treatment for each type of ameloblastoma differs depending on its biological behaviour and rate of recurrence. This report presents a case of ameloblastoma involving the body of mandible with resorption of the root apices of canine, premolars and first molar. The lesion extends till the base of mandible with intact lower border. This was surgically excised preserving the lower border of mandible with safe sound margins of bone.

Unicystic ameloblastoma: Clinico-radiological and histopathological correlation with management

Unicystic ameloblastoma is a distinct entity of ameloblastoma characterized by slow growth and relatively locally aggressive behavior. This retrospective study aimed to assess the efficacy of different treatment modalities for unicystic Ameloblastoma, focusing on clinic-radiological and histopathological features. Data from patients diagnosed with unicystic ameloblastoma were retrospectively analyzed. Patients were categorized into luminal and intraluminal (Group A), and mural (Group B) variants based on the Ackermann classification, which has a significant influence on their biological behavior, treatment approaches, and prognosis. Patients in Group A underwent enucleation with chemical cauterization and peripheral ostectomy and Iodoform packing, whereas those in Group B were treated with resection and reconstruction. Postoperatively, the patients were subjected to radiographic assessments via digital orthopantomogram (OPG) at regular intervals. Because of the rarity of unicystic ameloblastoma, 17 patients were included in the study (Group A: 9 patients; Group B: 8 patients), utilizing a mean follow-up of 4.9 years (range: 1.4 - 11.8 years).The primary outcome measure was the absence of recurrence, which indicated treatment success. No patient in either group presented with recurrence during the follow-up period. This study provides evidence supporting the successful treatment of luminal and intraluminal variants of unicystic ameloblastoma in young individuals using a conservative approach. However, the more aggressive mural variant demonstrated favorable outcomes with radical treatment. These findings emphasize the importance of Ackermann classification in guiding treatment decisions for unicystic ameloblastoma and contribute valuable insights into optimizing therapeutic strategies based on clinicoradiologic and histopathological findings.

A three-dimensional quantitative assessment on bony growth and symmetrical recovery of mandible after decompression for unicystic ameloblastoma

Unicystic ameloblastoma (UAM) of the jaw can be effectively reduced in volume through decompression, which promotes bone regeneration and restores jaw symmetry. This study quantitatively evaluated changes in mandible volume and symmetry following decompression of mandibular UAM. This study included 17 patients who underwent surgical decompression followed by second-stage curettage for mandibular UAM. Preoperative and postoperative three-dimensional computed tomography (CT) images were collected. Bone volume and the area of cortical perforation were measured to assess bone growth during decompression. Mandibular volumetric symmetry was analyzed by calculating the volumetric ratio of the two sides of the mandible. Twelve pairs of landmarks were identified on the surface of the lesion regions, and their coordinates were used to calculate the mean asymmetry index (AI) of the mandible. Paired t-tests and the Mann–Whitney U test were used for statistical analysis, with p < 0.05 considered indicative of statistical significance. The mean duration of decompression was 9.41 ± 3.28 months. The mean bone volume increased by 8.07 ± 2.41%, and cortical perforation recovery was 71.97 ± 14.99%. The volumetric symmetry of the mandible improved significantly (p < 0.05), and a statistically significant decrease in AI was observed (p < 0.05). In conclusion, UAM decompression enhances bone growth and symmetry recovery of the mandible. The present evaluation technique is clinically useful for quantitatively assessing mandibular asymmetry.

The efficacy of CBCT-based radiomics techniques in differentiating between conventional and unicystic ameloblastoma

ObjectiveThe aim of this study was to develop a cone beam computed tomography (CBCT) radiomics-based model that differentiates between conventional and unicystic ameloblastoma (AB). MethodsIn this retrospective study, CBCT images were collected from 100 patients who had ABs that were diagnosed histopathologically as conventional or unicystic AB after surgical treatment. The patients were randomly divided into training (70) and validation (30) cohorts. Radiomics features were extracted from the images, and the optimal features were incorporated into five models: Logistic Regression, Support Vector Machine, Linear Discriminant Analysis, Random Forest, and XGBoost for prediction of tumor type. Model performance was evaluated using the area under the curve (AUC) from receiver operating characteristic analysis, sensitivity, specificity, accuracy, calibration curves, and decision curve analysis (DCA). ResultsThe 20 optimal radiomics features were incorporated into the Logistic Regression (LR) model, which exhibited the best overall performance with AUC = 0.936 (95% CI, 0.877-0.996) for the training cohort and AUC = 0.929 (95%CI, 0.832-1.000) for the validation cohort. The nomogram combined the clinical features and the radiomics signature and resulted in the best predictive performance. ConclusionsThe LR model demonstrated the ability of radiomics and the nomogram to distinguish between the two types of AB and may have the potential to replace biopsies under noninvasive conditions.

Evaluation of Paxillin Expression in Odontogenic Cysts and Tumors.

Paxillin (PXN) is one of the proteins involved in cell adhesion. PXN and integrins constitute a key site for the focal adhesion between the cell and extracellular matrix. Several studies have shown that PXN is a factor in tumor formation, progression, invasion, and metastasis. This study evaluated PXN expression in four types of odontogenic lesions with different aggressive behaviors. In this retrospective cross-sectional study, PXN expression was immunohistochemically assessed in 68 paraffin-embedded tissue samples from patients with the confirmed diagnosis of four types of odontogenic lesions, including 14 dentigerous cysts (DC), 20 odontogenic keratocyst (OKC), 16 unicystic ameloblastoma, and 18 solid ameloblastoma. The PXN expression in these samples were scored based on the percentage and intensity of immunoreactivity, and compared among the groups by Chi-square test. The PXN marker was detected in the cytoplasm of tumor cells (unicystic and solid ameloblastoma) and the epithelial layer of cysts (DC and OKC). The intensively stained marker of PXN was observed in 9 cases (64.3%) of the DC, 14 cases (70%) of OKC, 12 cases (75%) of unicystic ameloblastoma, and 13 cases (72.2%) of solid ameloblastoma. However, there was not statistical difference of PXN protein expression between DC and OKC (p Value = 0.51) and unicystic and solid ameloblastoma (p = 0.58), also the same was true for cysts and tumors (p = 0.37). The expression of PXN is not related to the biological behaviors of odontogenic lesions.

Unicystic Ameloblastoma - A Case Report with Review of Literature

Unicystic Ameloblastoma - A Case Report with Review of Literature

Clinicopathological characteristics and diagnostic accuracy of BRAF mutations in ameloblastoma: A Bayesian network analysis.

This Bayesian network meta-analysis was performed to analyze the associations between clinicopathological characteristics and BRAF mutations in ameloblastoma (AM) patients and to evaluate the diagnostic accuracy. Four electronic databases were searched from 2010 to 2024. The search terms used were specific to BRAF and AM. Observational studies or randomized controlled trials were considered eligible. The incidence of BRAF mutation and corresponding clinicopathological features in AM patients were subjected to Bayesian network analyses and diagnostic accuracy evaluation. A total of 937 AM patients from 20 studies were included. The pooled prevalence of BRAF mutations in AM patients was 72%. According to the Bayesian network analysis, BRAF mutations are more likely to occur in younger (odds ratio [OR], 2.3; credible interval [CrI]: 1.2-4.5), mandible site (OR, 3.6; 95% CrI: 2.7-5.2), and unicystic (OR, 1.6; 95% CrI: 1.1-2.4) AM patients. Similarly, higher diagnostic accuracy was found in the younger, mandible, and unicystic AM groups. The incidence, risk, and diagnostic accuracy of BRAF mutation in AM were greater in younger patients, those with mandible involvement, and those with unicystic AM than in patients with other clinicopathological features. In addition, there was a strong concordance in the diagnostic accuracy between molecular tests and immunohistochemical analysis.

New perspectives in the differential diagnosis of jaw lesions: Machine learning and inflammatory biomarkers

This study aimed to assess the diagnostic performance of a machine learning approach that utilized radiomic features extracted from Cone Beam Computer Tomography (CBCT) images and inflammatory biomarkers for distinguishing between Dentigerous Cysts (DCs), Odontogenic Keratocysts (OKCs), and Unicystic Ameloblastomas (UAs). This retrospective study involves 103 patients who underwent jaw lesion surgery in the Maxillofacial Surgery Unit of Federico II University Of Naples between January 2018 and January 2023. Nonparametric Wilcoxon-Mann-Whitney and Kruskal Wallis tests were used for continuous variables. Linear and non-logistic regression models (LRM and NLRM) were employed, along with machine learning techniques such as decision tree (DT), k-nearest neighbor (KNN), and support vector machine (SVM), to predict the outcomes. When individual inflammatory biomarkers were considered alone, their ability to differentiate between OKCs, UAs, and DCs was below 50 % accuracy. However, a linear regression model combining four inflammatory biomarkers achieved an accuracy of 95 % and an AUC of 0.96. The accuracy of single radiomics predictors was lower than that of inflammatory biomarkers, with an AUC of 0.83. The Fine Tree model, utilizing NLR, SII, and one radiomic feature, achieved an accuracy of 94.3 % (AUC = 0.95) on the training and testing sets, and a validation set accuracy of 100 %. The Fine Tree model demonstrated the capability to discriminate between OKCs, UAs, and DCs. However, the LRM utilizing four inflammatory biomarkers proved to be the most effective algorithm for distinguishing between OKCs, UAs, and DCs.

Unicystic Ameloblastoma Mural Variant: A Case Report

Background: Ameloblastomas are a rare type of benign neoplastic tumors that are locally invasive and make up around 1% of all head-and-neck tumors. Mostly diagnosed in people between the ages of 30 and 60 years, it has a global incidence of about 0.5% of cases per million person years. Ameloblastomas are classified as multicystic, unicystic, peripheral, and desmoplastic variants. Unicystic ameloblastomas (UAs), accounting for about 6% of the cases, have a high recurrence rate. It is histologically divided into luminal, intraluminal, and mural types. As the mural variant is aggressive and has the highest chance of recurrence, radical resection of tumor is required. Case Presentation: A case of 47-year-old patient, diagnosed as unicystic mural variant of ameloblastoma presented to us in March 2023 at the department of head-and-neck surgery at a tertiary care setup in Karachi, Pakistan. Postoperatively, the patient is now on 6-month follow-up with no residual or recurrence report as of yet. Conclusion: We report a rare case of UA mural variant in the right mandible, which highlights the importance of prompt diagnosis and treatment of this type of ameloblastoma, particularly in a location where they can cause significant damage.

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.

An Unusual Case Report of Unicystic Ameloblastoma of the Mandible

ABSTRACT There are plenty of benign lesions that can result in swelling of the mandible, and these can be classified as odontogenic and non-odontogenic lesions. Among the categories of odontogenic lesion, ameloblastoma is the most occurring lesion that takes origin from the epithelial cellular elements and dental tissues in their different stages of development. Ameloblastoma is the most serious odontogenic neoplasm due to its prevalence and clinical characteristics. Ameloblastoma is a broad class which encompasses 80% of solid multicystic type of ameloblastoma with unicystic ameloblastoma (UA) variant included as vital clinicopathological form claiming the rest 20% along with peripheral ameloblastoma variant. UA refers to cystic lesions that seem like jaw cysts clinically, radiographically, or grossly but are lined by typical ameloblastomatous epithelium, with or without luminal and/or mural tumor development, on histologic investigation. Around 5–15% of all ameloblastic lesions do not have a propensity to metastasis, and this is UA. Unicystic mural form, although slow growing overall, is very invasive locally and has a high recurrence rate. As UA tumors show very close features with dentigerous cyst, a very sharp differential diagnosis protocol need to be executed to exclude the other unicystic odontogenic lesions considering the clinical, radiological, and biological characteristics along with proper follow-up and seeing any recurrence of the lesion taking place. Here, we report the case of a twenty-one year male patient with UA of the mandible and review of the literature.

Does YAP influence cell proliferation and apoptosis in benign epithelial odontogenic lesions?

To analyze the immunohistochemical expression of YAP and its correlation with markers involved in cell proliferation and apoptosis in benign epithelial odontogenic lesions. The sample consisted of 95 cases of odontogenic lesions (25 dentigerous cysts, 30 non-syndromic odontogenic keratocysts, 30 conventional ameloblastomas, and 10 unicystic ameloblastomas) and 10 dental follicles used as normal odontogenic tissue. The histological sections were submitted to immunohistochemistry with YAP, cyclin D1, Ki-67, and Bcl-2 antibodies. Immunoexpression was analyzed qualitatively and quantitatively using an adapted method. The collected data were analyzed descriptively and statistically (p ≤ 0.05). The highest YAP expression was observed in odontogenic keratocysts, followed by unicystic ameloblastomas and conventional ameloblastomas, which exhibited moderate immunoreactivity predominantly in peripheral cells. Furthermore, significant differences in YAP immunoexpression were observed between the groups analyzed, with significant positive correlations between YAP and cyclin D1 in dentigerous cysts and unicystic ameloblastomas and between YAP and Ki-67 in unicystic ameloblastomas (p < 0.05). However, there were no statistically significant correlations between YAP and Bcl-2 immunoexpression in the groups studied. YAP may influence epithelial cell proliferation in odontogenic cysts and tumors, suggesting its possible participation in the progression of the odontogenic lesions studied.

Conservative treatment of large unicystic ameloblastoma in a young patient: a 7-year follow-up

The unicystic ameloblastoma is an odontogenic tumor that is frequently found in young patients and usually affects the posterior region of the mandible. This paper aimed to describe a case report and 7-year follow-up of a young patient. The 12-year-old patient presented with increased volume in the lower third of the right hemiface with a duration of 6 months. Radiographic examination showed a unilocular radiolucent lesion extending along the body, angle and right mandibular ramus. An incisional biopsy was performed and a histological diagnosis of luminal unicystic ameloblastoma was obtained, opting for a conservative treatment with decompression and subsequent complete enucleation of the lesion. The patient has been under follow-up for 7 years, with a good evolution of the condition and without clinical and radiographic signs of recurrence of the lesion. Thus, it is ratified that timely conservative intervention and conservative surgical treatment should be the first choice for ameloblastoma management in young patients.

Immunohistochemical evaluation of yes-associated protein molecule in the odontogenic epithelium of different histopathological variants of ameloblastoma and unicystic ameloblastoma.

Ameloblastoma is one of the major odontogenic neoplasms with an invasive and recurrence potential. Its tumourigenesis and proliferative capacity can be attributed to the activation or inactivation of certain molecular signalling pathways. Hippo signalling pathway is known to regulate diverse physiological processes related to mitosis and organ growth and is an emerging tumour suppressor pathway, the dysfunction of which is implicated in various diseases including cancers. Yes-associated protein1 (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are the downstream effectors in the Hippo cascade, which on nuclear activation leads to cellular proliferation in various tumours. The current study was undertaken to evaluate the expression of YAP in various histopathological variants of ameloblastoma and unicystic ameloblastoma. Fifty formalin-fixed paraffin-embedded tissue samples of histopathologically diagnosed cases of ameloblastoma, and 10 histopathologically diagnosed cases of unicystic ameloblastoma were obtained from the departmental archives to evaluate the immunohistochemical expression of YAP both manually and by software analysis. More than 90% of cases of conventional ameloblastoma and unicystic ameloblastoma elicited positive expression of YAP. No statistical difference was found among different histopathological variants of conventional ameloblastoma. Significant difference between the means of all four quantitative score groups was observed. In view of the modulating effect of YAP in tumourigenesis and its higher expression in ameloblastoma, further exploration of this molecule appears to be a promising area of research.

Case of Unicystic Ameloblastoma with Features of Ameloblastic Fibro-dentinoma

Hybrid odontogenic tumours occur rarely in the oral cavity. The basic histogenesis of these lesions is not clear. Hybrid odontogenic tumours characteristically exhibit two or more distinct morphological features that may lead to a diagnostic dilemma. Unicystic Ameloblastomas (UA) are the second most common odontogenic tumour. Ameloblastic Fibro-dentinoma (AFD) is a rare mixed odontogenic tumour. Both UA and AFD commonly occur in the second decade of life, may be asymptomatic with a slight female predilection, and predominantly occur in the mandibular posterior region. Herein, the authors report a rare case of a 15-year-old female patient complaining of swelling in the right lower posterior jaw region in the last two months. The lesion was surgically enucleated and sent for histopathological examination. On histopathological examination, the lesion exhibits areas of both UA and AFD, representing a rare occurrence of a hybrid odontogenic tumour. The present case report highlights the unique combination of two odontogenic tumours of different origins