Differential diagnosis of cemento-osseous dysplasia and periapical cyst using texture analysis of CBCT.

BACKGROUND: Radiolucencies found at the root apex in patients with cemento-osseous dysplasia (COD) may be mistaken for periapical cysts (PC) of endodontic origin. The purpose of this study was to examine the utility of quantitative texture analysis using cone-beam computed tomography (CBCT) to differentiate between COD and PC. METHODS: Patients who underwent CBCT at Wonkwang University Daejeon Dental Hospital between January 2019 and December 2022 and were diagnosed with COD and PC by clinical, radiologic, and, if necessary, histopathologic examination were included. Twenty-five patients each were retrospectively enrolled in the COD and PC group. All lesions observed on axial CBCT images were manually segmented using the open-access software MaZda version 4.6 to establish the regions of interest, which were then subjected to texture analysis. Among the 279 texture features obtained, 10 texture features with the highest Fisher coefficients were selected. Statistical analysis was performed using the Mann-Whitney U-test, Welch's t-test, or Student's t-test. Texture features that showed significant differences were subjected to receiver operating characteristics (ROC) curve analysis to evaluate the differential diagnostic ability of COD and PC. RESULTS: The COD group consisted of 22 men and 3 women, while the PC group consisted of 14 men and 11 women, showing a significant difference between the two groups in terms of sex (p=0.003). The 10 selected texture features belonged to the gray level co-occurrence matrix and included the sum of average, sum of entropy, entropy, and difference of entropy. All 10 selected texture features showed statistically significant differences (p<0.05) when comparing patients with COD (n=25) versus those with PC (n=25), osteolytic-stage COD (n=11) versus PC (n=25), and osteolytic-stage COD (n=11) versus cementoblastic-stage COD (n=14). ROC curve analysis to determine the ability to differentiate between COD and PC showed a high area under the curve ranging from 0.96 to 0.98. CONCLUSION: Texture analysis of CBCT images has shown good diagnostic value in the differential diagnosis of COD and PC, which can help prevent unnecessary endodontic treatment, invasive biopsy, or surgical intervention associated with increased risk of infection.

Management regulations for odontogenic keratocyst: a case report and review of the literature.

BACKGROUND: Reconstruction of the entire dentition with odontogenic keratocyst is a very challenging quandary. Most cases of odontogenic keratocyst are often reported to be benign, resulting in severe occlusal discrepancies with the maxillary and mandibular dentition. Dental radiographs occasionally reveal an uncommon, locally aggressive developing cyst termed as odontogenic keratocyst, which is typically located in the posterior jaw. When this cyst occurs in the anterior region, it is often misdiagnosed with other periapical lesions due to its lack of response to pulp vitality tests. CASE PRESENTATION: This clinical case scenario demarcates the endodontic management of a patient diagnosed with odontogenic keratocyst. A 37-year-old Indian male patient reported to the department with throbbing pain in the lower left posterior tooth requiring endodontic therapy. This patient also presented with odontogenic keratocyst in the anterior region of the jaw, for which he had undergone surgical rehabilitation. This case report highlights the clinical protocol for the endodontic therapy in patient diagnosed with ododntogenic keratocyst. Masticatory impairment was not visible after the follow-up period and the treatment outcome was successful. CONCLUSION: This case report details the presentation, characteristic radiographic findings, and endodontic management of a patient with an extremely rare condition of odontogenic keratocyst. The management involves multidisciplinary approach for the rehabilitation.

Challenging pitfalls in frozen section pathology: a case of mandible ghost cell odontogenic carcinoma and the literature review.

BACKGROUND: Ghost cell odontogenic carcinoma (GCOC) is a rare malignancy characterized by the presence of ghost cells, preferably in the maxilla. Only slightly more than 50 case reports of GCOC have been documented to date. Due to the rarity of this tumor and its nonspecific clinical criteria, there is a heightened risk of misdiagnosis in clinical examination, imaging findings, and pathology interpretation. CASE PRESENTATION: A 50-year-old male patient presented to the hospital due to experiencing pain in his lower front teeth while eating for the past 2 months. Upon examination, a red, hard, painless mass was found in his left lower jaw, measuring approximately 4.0 cm × 3.5 cm. Based on the malignant histological morphology of the tumor and the abundant red-stained keratinized material, the preoperative frozen section pathology misdiagnosed it as squamous cell carcinoma (SCC). The surgical resection specimen pathology via paraffin section revealed that the tumor was characterized by round-like epithelial islands within the fibrous interstitium, accompanied by a large number of ghost cells and some dysplastic dentin with infiltrative growth. The malignant components displayed marked heterogeneity and mitotic activity. Additionally, a calcified cystic tumor component of odontogenic origin was observed. Hemorrhage, necrosis, and calcifications were present, with a foreign body reaction around ghost cells. Immunoreactivity for ß-catenin showed strong nuclear positivity in tumor cells, while immunostaining was completely negative for p53. The Ki67 proliferation index was approximately 30-40%. The tumor cells exhibited diffuse CK5/6, p63, and p40 immunoreactivity, with varying immunopositivity for EMA. Furthermore, no BRAFV600E mutation was identified by ARMS-PCR. The final pathology confirmed that the tumor was a mandible GCOC. CONCLUSION: We have reported and summarized for the first time the specific manifestations of GCOC in frozen section pathology and possible pitfalls in misdiagnosis. We also reviewed and summarized the etiology, pathological features, molecular characteristics, differential diagnosis, imaging features, and current main treatment options for GCOC. Due to its rarity, the diagnosis and treatment of this disease still face certain challenges. A correct understanding of the pathological morphology of GCOC, distinguishing the ghost cells and the secondary stromal reaction around them, is crucial for reducing misdiagnosis rates.

Recurrent cementoblastoma with multifocal growth and cellular atypia: a case report.

BACKGROUND: Cementoblastoma is a rare odontogenic tumor characterized by the formation of osteocementum-like tissue on a tooth root directly by neoplastic cementoblasts. Although it is categorized as benign, it has a high potential for growth with a certain degree of recurrence risk. However, there are only a few studies describing the features of recurrent cementoblastoma. The diagnosis of recurrent cementoblastoma is challenging not only due to its cytological atypia but also because of its large size and multicentric growth pattern. These characteristics suggest a potential for malignancy. CASE PRESENTATION: A 29-year-old woman was transferred to our university dental hospital complaining of swelling of the right mandible. She had a history of enucleation of cementoblastoma associated with the third molar of the right mandible. Five years after the initial treatment, imaging demonstrated well-circumscribed multicentric radiopaque lesions in the same area. Histologically, the lesion consisted of osteocementum-like tissue rimmed with polygonal or plump tumor cells. Several cells were large epithelioid cells with bizarre nucleoli, which may be reminiscent of malignant tumors. Otherwise, there were no apparent malignant findings, including proliferative activity or atypical mitotic figure. Besides, tumor cells were positive for c-FOS, a marker of osteoblastoma and cementoblastoma. Eventually, the patient was diagnosed with recurrent cementoblastoma. CONCLUSIONS: Pathological analyses of this case suggested that the recurrent event in the cementoblastoma altered its growth pattern and tumor cell shape. Moreover, in the case of enucleation surgery, long-term follow-up is important because there is some recurrent risk of cementoblastoma, although it is not high.

Reticular Myxoid Odontogenic Neoplasm with Novel STRN::ALK Fusion: Report of 2 Cases in 3-Year-Old Males.

Odontogenic tumors represent a collection of entities ranging from hamartomas to destructive benign and malignant neoplasms. Occasionally, pathologists encounter gnathic lesions which clearly exhibit an odontogenic origin but do not fit within the confines of established diagnoses. Here, we describe two such odontogenic tumors, both affecting 3-year-old males. Each case presented as a destructive, radiolucent mandibular lesion composed of mesenchymal cells, some with unique multi-lobed nuclei, frequently arranged in a reticular pattern and supported by a myxoid stroma with focal laminations. Production of odontogenic hard tissues was also seen. Because of their unique microscopic features, both cases were investigated by next-generation sequencing and found to harbor the same STRN::ALK oncogene fusion. To our knowledge, these cases represent the first report of an odontogenic tumor with a STRN::ALK gene rearrangement. We propose the possibility that this neoplasm could be separate from other known odontogenic tumors. Both patients were treated with surgical resection and reconstruction. The prognosis of patients with this entity is currently uncertain but shall become more apparent over time as more cases are identified and followed.

A Comparison of Clear Cell Sarcoma to Jaw and Salivary Tumors Bearing EWS Fusions.

OBJECTIVE: To review tumors identified as "clear cell sarcoma" in order to determine similarities to the rare EWS fusion positive jaw and salivary gland tumors clear cell odontogenic carcinoma (CCOC) and clear cell carcinoma of the salivary gland (CCC). METHODS: PubMed was used to collect all reports of clear cell sarcoma (CCS). Search parameters were "clear cell sarcoma" and "CCS." References in the publications were screened and cross-referenced. Data extracted included demographic characteristics, presenting signs and symptoms, radiographic findings, histological and immunohistochemical features and known molecular/genetic aberrations. RESULTS: Clear cell sarcoma has several similarities to CCOC and CCC. All three tumor types have similar histologic appearances including the presence of clear cells, as well as similar genetic profiles in that all harbor an EWSR1-CREB family fusions. Additionally, these tumors appear in soft tissue as well as bone, and can have a prolonged clinical course. CCS can appear anywhere in the body, including the head and neck region. All three tumors appear to have a predilection to women, although CCS may have a slight younger age of onset as compared to CCOC and CCC (3rd vs 5th decade of life, respectively). CONCLUSION: Gaining a better understanding of the similarities and differences between these three tumors may lead to a better understanding of each one.

Tumor immune microenvironment in odontogenic carcinomas: Evaluation of the therapeutic potential of immune checkpoint blockade.

BACKGROUND: Despite recent advances in the use of immune checkpoint blockade (ICB) across various cancer types, its efficacy in odontogenic carcinomas remains unexplored. This study aims to investigate PD-L1 expression and the tumor immune microenvironment (TIME) in odontogenic carcinomas to determine the therapeutic potential of ICB and the significance of immune markers. METHODS: The expressions of PD-L1 and T cell markers (CD3, CD8, and FOXP3) were visualized by immunohistochemistry in 21 tissue samples of odontogenic carcinomas. Tumoral PD-L1 expression and the density and spatial distribution of T cell subsets were evaluated, from which TIME was determined. The associations of the variables with clinicopathological and prognostic factors were statistically analyzed. RESULTS: PD-L1 was positively expressed in 52.4% (11/21) of the cases studied. Among tumor types, ameloblastic carcinoma showed significantly higher PD-L1 expression (p = 0.016). TIME based on the intratumoral and stromal T cell distribution was immune-inflamed in 61.9% (13/21) and immune-excluded in 38.1% (8/21), with no immune-desert cases. PD-L1 expression was associated with the densities of all intratumoral T cell subsets (p = 0.03 for CD3, p = 0.03 for CD8, and p = 0.008 for FOXP3) but not with those of stromal T cells. High PD-L1 expression was associated with larger tumor size (p = 0.021), while the intratumoral CD8/CD3 ratio was inversely correlated with tumor size (p = 0.048). CONCLUSION: These findings indicate the involvement of adaptive immune resistance in a subset of odontogenic carcinomas and support the therapeutic potential of ICB in patients with these rare malignancies.

Ossifying fibroma mimiking jaw tumour: A radiographic dilema.

Fibro-osseous lesions (FOLs) of the craniomaxillofacial region comprise a group of developmental, dysplastic, and neoplastic alterations. FOLs include ossifying fibromas (OF), cemento-ossifying fibroma (COF), familial gigantiform cementoma (FGC), fibrous dysplasia (FD), and cemento-osseous dysplasia (COD). Evidence suggests that some FOL, especially FD and OF may have a risk of spontaneous malignant transformation. This report documents a rare case of malignant transformation of ossifying fibromas of the jaw and the probable cause for same. Although it is rare, the clinician should have a complete follow up to observe such changes among the patients having FOLs.

Gorlin-Goltz Syndrome - A Rare Case Entity in Young Child.

Gorlin-Goltz syndrome (GGS) is an infrequent multisystemic disease with an autosomal dominant trait, which depicted presence of numerous basal cell carcinoma in conjunction with multiorgan abnormalities. This syndrome may be diagnosed early by a dentist by routine radiographic exams in the first decade of life, since the keratocystic odontogenic tumour are usually one of the first manifestations of the syndrome. This article includes a case report of the GGS with regard to its history, incidence, etiology, features, investigations, diagnostic criteria, keratocystic odontogenic tumour and treatment modalities.

In Silico Analysis of Genes Associated with the Pathogenesis of Odontogenic Keratocyst.

Odontogenic keratocyst (OK) is a benign intraosseous cystic lesion characterized by a parakeratinized stratified squamous epithelial lining with palisade basal cells. It represents 10-12% of odontogenic cysts. The changes in its classification as a tumor or cyst have increased interest in its pathogenesis. OBJECTIVE: Identify key genes in the pathogenesis of sporadic OK through in silico analysis. MATERIALS AND METHODS: The GSE38494 technical sheet on OK was analyzed using GEOR2. Their functional and canonical signaling pathways were enriched in the NIH-DAVID bioinformatic platform. The protein-protein interaction network was constructed by STRING and analyzed with Cytoscape-MCODE software v 3.8.2 (score > 4). Post-enrichment analysis was performed by Cytoscape-ClueGO. RESULTS: A total of 768 differentially expressed genes (DEG) with a fold change (FC) greater than 2 and 469 DEG with an FC less than 2 were identified. In the post-enrichment analysis of upregulated genes, significance was observed in criteria related to the organization of the extracellular matrix, collagen fibers, and endodermal differentiation, while the downregulated genes were related to defensive response mechanisms against viruses and interferon-gamma activation. CONCLUSIONS: Our in silico analysis showed a significant relationship with mechanisms of extracellular matrix organization, interferon-gamma activation, and response to viral infections, which must be validated through molecular assays.

Imaging Characteristics of Embedded Tooth-Associated Cemento-Osseous Dysplasia by Retrospective Study.

BACKGROUND: Since there are many differential diagnoses for cemento-osseous dysplasia (COD), it is very difficult for dentists to avoid misdiagnosis. In particular, if COD is related to an embedded tooth, differential diagnosis is difficult. However, there have been no reports on the characteristics of the imaging findings of COD associated with embedded teeth. The aim of the present study was to investigate the occurrence and imaging characteristics of cemento-osseous dysplasia (COD) associated with embedded teeth, in order to appropriately diagnose COD with embedded teeth. METHODS: The radiographs with or without histological findings of 225 patients with COD were retrospectively analyzed. A retrospective search through the picture archiving and communication system (PACS) of the Division of Oral and Maxillofacial Radiology of Kyushu Dental University Hospital was performed to identify patients with COD between 2011 and 2022. RESULTS: Fifteen COD-associated embedded mandibular third molars were identified in 13 patients. All 13 patients were asymptomatic. On imaging, COD associated with embedded mandibular third molars appeared as masses that included calcifications around the apex of the tooth. On panoramic tomography, COD showed inconspicuous internal calcification similar to that of odontogenic cysts or simple bone cysts, especially in patients with COD only around the mandibular third molar region. Those with prominent calcification resembled cemento-ossifying fibroma, calcifying epithelial odontogenic tumor, calcifying odontogenic cyst, adenomatoid odontogenic tumor, and so on, as categories of masses that include calcifications on panoramic tomography and computed tomography. CONCLUSIONS: The current investigation is the first to report and analyze the imaging characteristics of COD associated with embedded teeth. It is important to consider the differences between COD and other cystic lesions on panoramic tomography, and the differences between COD and masses that include calcifications on CT.

Ameloblastic carcinoma: A systematic review.

BACKGROUND: Ameloblastic carcinoma (AC) is the most common odontogenic malignancy, constituting approximately 30% of cases in this category. Literature is sparse on malignant odontogenic neoplasms, with a large proportion of current knowledge derived from case reports or small case series. METHODS: A systematic review of case series/case reports of AC was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Statement guidelines. Demographic and clinical information, including duration of the lesion, location, clinical presentation and radiologic features, were analysed. Additionally, the origin of the lesion (primary/secondary), Ki-67 proliferation index, treatment performed, metastasis, tumour recurrence and prognosis were collected for analysis. RESULTS: A total of 126 studies, including 285 individual cases of AC, were included in this review. Patients presented with a near-equal distribution of painless and painful swellings. ACs presented at a median age of 45 years, with a male-to-female ratio of 1:2. The mandible was most frequently involved, with rare cases extending to involve more than one region, including crossing the midline. Although most lesions presented with poorly-demarcated borders (52.6%), unilocular lesions with well-demarcated borders (47.4%) comprised a substantial number in the sample. The proliferation index was only reported in 27 cases, with a mean score of 42% and a wide range. The probability of tumour recurrence increased, and the survival probability decreased with prolonged follow-up duration. CONCLUSION: This study provides more comprehensive, up-to-date descriptive data on these rare odontogenic malignancies, aiding clinicians and Pathologists with the diagnosis and surgeons in their management of cases.

[Three-dimensional radiographic features of calcifying odontogenic cyst and calcifying epithelial odontogenic tumor].

OBJECTIVE: To analyze the three-dimensional radiographic characteristics of calcifying odontogenic cyst and calcifying epithelial odontogenic tumor using spiral computed tomography (CT) and cone-beam computed tomography (CBCT). METHODS: Clinical records, histopathological reports, and CBCT or non-enhanced spiral CT images of 19 consecutive patients with calcifying odontogenic cyst (COC) and 16 consecutive patients with calcifying epithelial odontogenic tumor (CEOT) were retrospectively acquired, and radiographic features, including location, size, expansion, internal structure and calcification, were analyzed. RESULTS: Among the 19 COC cases (12 males and 7 females, with an average age of 27 years), 89.5% (17/19) of the lesions originated from the anterior and premolar areas, 100.0% of them exhibited cortex expansion, and 78.9% had discontinued cortex. Among the 16 CEOT cases (3 males and 13 females, with an average age of 36 years), 81.3% (13/16) of the lesions were in the premolar and molar areas, 56.3% of them exhibited cortex expansion, and 96.8% had discontinued cortex. According to the distribution of internal calcifications, these lesions were divided into: Ⅰ (non-calcification type): absence of calcification; Ⅱ (eccentric marginal type): multiple calcifications scattered along one side of the lesion; Ⅲ (diffused type): numerous calcifications diffusely distributed into the lesion; Ⅳ (plaque type): with a ≥ 5 mm calcified patch; Ⅴ (peri-coronal type): multiple calcifications clustered around impacted teeth. Calcifications were present in 73.7% of COC lesions, including 9 type Ⅱ, 3 type Ⅲ and 2 type Ⅳ lesions, and 42.8% of CEOT lesions had calcification images, including 2 type Ⅲ and 5 type Ⅴ lesions. Six COC lesions had odontoma-like images. Moreover, 8 of 9 type Ⅰ CEOTs were histologically Langerhans cell-rich subtype, which had a smaller size (with an average mesiodistal diameter of 17.8 mm) and were not associated with impacted teeth. CONCLUSION: COC lesions tended to originate from the anterior part of the jaw and exhibit cortex expansion, and were sometimes associated with odontoma. CEOT commonly occurred in the posterior jaw and had discontinued cortex. Two lesions had significantly different calcification map. Over 70% of COC lesions had calcification images, which were mostly scattered along one side of the cysts, far from the impacted teeth. Approximately 60% of CEOT lesions exhibited smaller size and non-calcification, and the remaining CEOT cases often had calcification images clustered around the impacted teeth.

Long-term investigation of minimally invasive alcohol-based therapy as the treatment of odontogenic keratocyst:A retrospective cohort study.

The aim of this study was to evaluate the clinical efficacy of alcohol-based therapy for patients with large odontogenic keratocysts (OKCs). The study was implemented as a retrospective, single-center study. Patients treated with ethanol-based therapy for odontogenic keratocyst were retrospectively evaluated for baseline and postoperative data. The pre- and postoperative clinical situation and the extent of radiographic shrinkage were compared. The event is defined as the achievement of >50% reduction in cyst volume. The cyst reduction rate calculated on panoramic radiographs ranged from 7.4% to 99.9% (mean [standard deviation] 55.3% [27.9%]) and was statistically significant (P < 0.05). Specifically, it has been found that, radiographically, 47.6% of patients achieved >50% reduction in cyst volume within 12 months. The continuous cortical bone was rebuilt, and the cyst cavity was filled with regenerated trabecular bone. The 22 included patients presented with nonclinical problems, had no need for further intervention, and exhibited persistent impaction of the teeth. The results of this study demonstrated that ethanol-based therapy triggered marked radiographic reductions of large OKC, indicating that using this technique is efficient.

Digital pathology-based artificial intelligence models for differential diagnosis and prognosis of sporadic odontogenic keratocysts.

Odontogenic keratocyst (OKC) is a common jaw cyst with a high recurrence rate. OKC combined with basal cell carcinoma as well as skeletal and other developmental abnormalities is thought to be associated with Gorlin syndrome. Moreover, OKC needs to be differentiated from orthokeratinized odontogenic cyst and other jaw cysts. Because of the different prognosis, differential diagnosis of several cysts can contribute to clinical management. We collected 519 cases, comprising a total of 2 157 hematoxylin and eosin-stained images, to develop digital pathology-based artificial intelligence (AI) models for the diagnosis and prognosis of OKC. The Inception_v3 neural network was utilized to train and test models developed from patch-level images. Finally, whole slide image-level AI models were developed by integrating deep learning-generated pathology features with several machine learning algorithms. The AI models showed great performance in the diagnosis (AUC = 0.935, 95% CI: 0.898-0.973) and prognosis (AUC = 0.840, 95%CI: 0.751-0.930) of OKC. The advantages of multiple slides model for integrating of histopathological information are demonstrated through a comparison with the single slide model. Furthermore, the study investigates the correlation between AI features generated by deep learning and pathological findings, highlighting the interpretative potential of AI models in the pathology. Here, we have developed the robust diagnostic and prognostic models for OKC. The AI model that is based on digital pathology shows promise potential for applications in odontogenic diseases of the jaw.

Cysts and Benign Odontogenic Tumors of the Jaws.

This article addresses jaw lesions including cysts and benign odontogenic tumors in terms of their definition and clinical and imaging features and discusses pertinent differential diagnoses..

Immunohistochemical expression of SPARC in odontogenic keratocysts: a comparative study with other odontogenic cysts.

BACKGROUND: Secreted protein acidic and rich in cysteine (SPARC) has been shown to modulate aggressive behavior in several benign and malignant tumors. Little is known about SPARC expression in odontogenic keratocyst (OKC), an odontogenic cyst with an aggressive nature. To the best of our knowledge, only one study has been investigated the expression of this protein in OKCs. This study aimed to characterize SPARC expression in OKCs. Additionally, to determine whether SPARC is associated with aggressive behavior in OKCs, SPARC expression in OKCs was compared with radicular cysts (RCs), dentigerous cysts (DCs) and calcifying odontogenic cysts (COCs). These odontogenic cysts showed no or less aggressive behavior. METHODS: SPARC expression was evaluated in 38 OKCs, 39 RCs, 35 DCs and 14 COCs using immunohistochemistry. The percentages of positive cells and the intensities of immunostaining in the epithelial lining and the cystic wall were evaluated and scored. RESULTS: Generally, OKCs showed similar staining patterns to RCs, DCs and COCs. In the epithelial lining, SPARC was not detected, except for ghost cells in all COCs. In the cystic wall, the majority of positive cells were fibroblasts. Compared between 4 groups of odontogenic cysts, SPARC expression in OKCs was significantly higher than those of RCs (P < 0.001), DCs (P < 0.001) and COCs (P = 0.001). CONCLUSIONS: A significant increase of SPARC expression in OKCs compared with RCs, DCs and COCs suggests that SPARC may play a role in the aggressive behavior of OKCs.

Clinicopathological characteristics of odontogenic carcinosarcoma: A systematic review.

BACKGROUND: The aim of the present systematic review was to summarize evidence on odontogenic carcinosarcoma, analyzing clinical, epidemiological, imaging, histopathological, immunohistochemical, therapeutic, and prognostic features of this tumor. MATERIALS AND METHODS: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches were performed in the Ovid MEDLINE (Wolters Kluwer), PubMed (National Library of Medicine), Web of Science (Thomson Reuters), Scopus (Elsevier), and LILACS (Latin American and Caribbean Center on Health Sciences Information) databases, without publication date or language restrictions. Case reports or case series of OCS reporting clinical, radiological, and histopathological data that confirmed the diagnosis were selected. The Joanna Briggs Institute-University of Adelaide tool was used for critical appraisal of the included articles. RESULTS: Odontogenic carcinosarcoma is a rare, aggressive tumor associated with high mortality; however, the metastasis rate is low. The tumor has a male predilection. The mean patient age is 40 years, but there is no predilection for age. The left posterior mandible is the most affected site, but no specific radiographic features have been reported. CONCLUSION: Given its rarity, dentists, oral-maxillofacial surgeons, and physicians need to be aware of odontogenic carcinosarcoma in order to increase the diagnostic potential, preventing delays in diagnosis and treatment and thus contributing to lower morbidity of the tumor.

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.