Comprehensive Genomic Analysis of Cemento-Ossifying Fibroma.

Cemento-ossifying fibroma (COF) of the jaws is currently classified as a benign mesenchymal odontogenic tumor, and only targeted approaches have been used to assess its genetic alterations. A minimal proportion of COFs harbor CDC73 somatic mutations, and copy number alterations (CNAs) involving chromosomes 7 and 12 have recently been reported in a small proportion of cases. However, the genetic background of COFs remains obscure. We used a combination of whole-exome sequencing and RNA sequencing to assess somatic mutations, fusion transcripts, and CNAs in a cohort of 12 freshly collected COFs. No recurrent fusions have been identified among the 5 cases successfully analyzed by RNA sequencing, with in-frame fusions being detected in 2 cases (MARS1::GOLT1B and PARG::BMS1 in one case and NCLN::FZR1 and NFIC::SAMD1 in the other case) and no candidate fusions identified for the remaining 3 cases. No recurrent pathogenic mutations were detected in the 11 cases that had undergone whole-exome sequencing. A KRAS p.L19F missense variant was detected in one case, and 2 CDC73 deletions were detected in another case. The other variants were of uncertain significance and included variants in PC, ACTB, DOK6, HACE1, and COL1A2 and previously unreported variants in PTPN14, ATP5F1C, APOBEC1, HDAC5, ATF7IP, PARP2, and ACTR3B. The affected genes do not clearly converge on any signaling pathway. CNAs were detected in 5/11 cases (45%), with copy gains involving chromosome 12 occurring in 3/11 cases (27%). In conclusion, no recurrent fusions or pathogenic variants have been detected in the present COF cohort, with copy gains involving chromosome 12 occurring in 27% of cases.

CT-based radiomics analysis of different machine learning models for differentiating gnathic fibrous dysplasia and ossifying fibroma.

OBJECTIVE: In this study, our aim was to develop and validate the effectiveness of diverse radiomic models for distinguishing between gnathic fibrous dysplasia (FD) and ossifying fibroma (OF) before surgery. MATERIALS AND METHODS: We enrolled 220 patients with confirmed FD or OF. We extracted radiomic features from nonenhanced CT images. Following dimensionality reduction and feature selection, we constructed radiomic models using logistic regression, support vector machine, random forest, light gradient boosting machine, and eXtreme gradient boosting. We then identified the best radiomic model using receiver operating characteristic (ROC) curve analysis. After combining radiomics features with clinical features, we developed a comprehensive model. ROC curve and decision curve analysis (DCA) demonstrated the models' robustness and clinical value. RESULTS: We extracted 1834 radiomic features from CT images, reduced them to eight valuable features, and achieved high predictive efficiency, with area under curves (AUC) exceeding 0.95 for all the models. Ultimately, our combined model, which integrates radiomic and clinical data, displayed superior discriminatory ability (AUC: training cohort 0.970; test cohort 0.967). DCA highlighted its optimal clinical efficacy. CONCLUSION: Our combined model effectively differentiates between FD and OF, offering a noninvasive and efficient approach to clinical decision-making.

Giant fronto-spheno-orbitary juvenile psammomatoid ossifying fibroma: Case report and literature review.

Juvenile psammomatoid ossifying fibroma (JPOF) is an osteofibrous neoplasm that originates in the craniofacial skeleton typically during the first three decades of life. JPOFs usually involve the orbit, paranasal sinuses or the jaws. Extensive involvement of the anterior cranial base with compromised visual function is a rare phenomenon. In such clinical context, a definite diagnosis can only be made on the basis of histopathological findings, given the absence of pathognomonic radiological features. Despite being considered a benign entity, JPOFs present a locally aggressive behavior. Therefore, these neoplasms must be included in the differential diagnosis in every patient harboring a skull base osteofibrous lesion, and, once diagnosed, gross total surgical removal should be attempted. In this study, we present our experience in the diagnosis and treatment of a patient diagnosed with a giant JPOF involving the cranial base.

Jaffe-Campanacci syndrome; a case series and review of the literature.

BACKGROUND: Jaffe-Campanacci syndrome is a rare syndrome, characterized by multiple non-ossifying fibromas (NOF) and cafe-au-lait patches. The name was coined in 1982 by Mirra after Jaffe who first described the case in 1958. Although it's suggested there is a relation with Neurofibromatosis type 1, there is still no consensus on whether Jaffe-Campanacci syndrome is a subtype or variant of neurofibromatosis-1(NF-1). CASE PRESENTATION: In this article, we present a case series of 2 patients. The first case is a 13-year-old male with Jaffe-Campanacci syndrome who presented with a distal femur fracture. His father had positive features of both Jaffe-Campanacci syndrome and NF-1, while his sister only had features of NF-1, so we presented both. CONCLUSION: Jaffe-Campanacci has a clear relationship with type 1 neurofibromatosis, which still has to be genetically established. Due to the presence of several large non-ossifying fibromas of the long bones, it is linked to a significant risk of pathological fractures. We concur with previous authors, that an osseous screening program should be performed for all patients with newly diagnosed type 1 neurofibromatosis, to identify non-ossifying fibromas and assess the potential for pathological fracture. Moreover, siblings of patients with NF-1 should be screened for multiple NOFs that may carry a high risk of pathological fractures.

Psammomatoid Ossifying Fibroma Is Defined by SATB2 Rearrangement.

Psammomatoid ossifying fibroma (PsOF), also known as juvenile PsOF, is a benign fibro-osseous neoplasm predominantly affecting the extragnathic bones, particularly the frontal and ethmoid bones, with a preference for adolescents and young adults. The clinical and morphologic features of PsOF may overlap with those of other fibro-osseous lesions, and additional molecular markers would help increase diagnostic accuracy. Because identical chromosomal breakpoints at bands Xq26 and 2q33 have been described in 3 cases of PsOF located in the orbita, we aimed to identify the exact genes involved in these chromosomal breakpoints and determine their frequency in PsOF using transcriptome sequencing and fluorescence in situ hybridization (FISH). We performed whole RNA transcriptome sequencing on frozen tissue in 2 PsOF index cases and identified a fusion transcript involving SATB2, located on chromosome 2q33.1, and AL513487.1, located on chromosome Xq26, in one of the cases. The fusion was validated using reverse transcription (RT)-PCR and SATB2 FISH. The fusion lead to a truncated protein product losing most of the functional domains. Subsequently, we analyzed an additional 24 juvenile PsOFs, 8 juvenile trabecular ossifying fibromas (JTOFs), and 11 cemento-ossifying fibromas (COFs) for SATB2 using FISH and found evidence of SATB2 gene rearrangements in 58% (7 of 12) of the evaluable PsOF cases but not in any of the evaluable JTOF (n = 7) and COF (n = 7) cases. A combination of SATB2 immunofluorescence and a 2-color SATB2 FISH in our index case revealed that most tumor cells harboring the rearrangement lacked SATB2 expression. Using immunohistochemistry, 65% of PsOF, 100% of JTOF, and 100% of COF cases showed moderate or strong staining for SATB2. In these cases, we observed a mosaic pattern of expression with >25% of the spindle cells in between the bone matrix, with osteoblasts and osteocytes being positive for SATB2. Interestingly, 35% (8 of 23) of PsOFs, in contrast to JTOFs and COFs, showed SATB2 expression in <5% of cells. To our knowledge, this is the first report that shows the involvement of SATB2 in the development of a neoplastic lesion. In this study, we have showed that SATB2 rearrangement is a recurrent molecular alteration that appears to be highly specific for PsOF. Our findings support that PsOF is not only morphologically and clinically but also genetically distinct from JTOF and COF.

Quantitative proteomic study reveals differential expression of matricellular proteins between fibrous dysplasia and cemento-ossifying fibroma pathogenesis.

BACKGROUND: Fibrous dysplasia (FD) and cemento-ossifying fibroma (COF) are the most common gnathic fibro-osseous lesions. These diseases exhibit remarkable overlap of several clinicopathological aspects, and differential diagnosis depends on the combination of histopathological, radiographic, and clinical aspects. Their molecular landscape remains poorly characterized, and herein, we assessed their proteomic and phosphoproteomic profiles. METHODS: The quantitative differences in protein profile of FD and COF were assessed by proteomic and phosphoproteomic analyses of formalin-fixed paraffin-embedded tissue samples. Pathway enrichment analyses with differentially regulated proteins were performed. RESULTS: FD and COF exhibited differential regulation of pathways related to extracellular matrix organization, cell adhesion, and platelet and erythrocytes activities. Additionally, these lesions demonstrated distinct abundance of proteins involved in osteoblastic differentiation and tumorigenesis and differential abundance of phosphorylation of Ser61 of Yes-associated protein 1 (YAP1). CONCLUSIONS: In summary, despite the morphological similarity between these diseases, our results demonstrated that COF and DF present numerous quantitative differences in their proteomic profiles. These findings suggest that these fibro-osseous lesions trigger distinct molecular mechanisms during their pathogenesis. Moreover, some proteins identified in our analysis could serve as potential biomarkers for differential diagnosis of these diseases after further validation.

Non-ossifying fibromas and fibrous cortical defects around the knee - an epidemiologic survey in a Japanese pediatric population.

BACKGROUND: The aim of the present study was to evaluate the prevalence of non-ossifying fibroma (NOF) and fibrous cortical defect (FCD) in a Japanese pediatric population and the association between the lesion size and pain. METHODS: This retrospective study, conducted across 10 Japanese institutions, included patients aged 5-15 years who had undergone standard antero-posterior and lateral view radiography of the knee. Using these radiographs, we diagnosed the lesion as a NOF or FCD. Patient demographics, including age, sex, the size and location of the NOF, and chief complaint were recorded. The lesion size was determined using radiographs. Student's t-test was used to compare the associations between the lesion size and spontaneous pain. RESULTS: A total of 6222 subjects (3567 boys and 2455 girls) were included in this study. The number of NOF and FCD cases was 143 and 437, respectively, and the prevalence of NOF and FCD was 2.3% and 7.0%, respectively. The average size of NOF and FCD was 22.1 mm (range: 4-102 mm) and 13.2 mm (range: 5-21 mm), respectively. Three patients (2.1%) had pathological fractures due to NOF. Of the 140 NOFs and 437 FCDs, we obtained complaints from the medical records of 126 and 393 patients, respectively. The number of patients with spontaneous pain or other problems with NOF was 68 (54%) and 58 (46%), respectively, that of patients with FCD was 195 (50%) and 198 (50%) patients, respectively. The lesion size was not associated with spontaneous pain in either lesion (p = 0.67 and p = 0.27, respectively). CONCLUSION: The prevalence of NOF and FCD around the knee was lower than that reported in previous studies. The prevalence of NOF increased and that of FCD decreased with advancing age. In both lesions, the lesion size may not be associated with pain.

Making sense of giant cell lesions of the jaws (GCLJ): lessons learned from next-generation sequencing.

Next-generation sequencing has revealed mutations in several bone-related lesions and was recently used to uncover the genetic basis of giant cell lesions of the jaws (GCLJ). Consistent with their benign nature, GCLJ show a low tumor mutation burden. They also harbor somatic, heterozygous, mutually exclusive mutations in TRPV4, KRAS, or FGFR1. These signature mutations occur only in a subset of lesional cells, suggesting the existence of a 'landscaping effect', with mutant cells inducing abnormal accumulation of non-mutant cells that form the tumor mass. Osteoclast-rich lesions with histological similarities to GCLJ can occur in the jaws sporadically or in association with genetically inherited syndromes. Based on recent results, the pathogenesis of a subgroup of sporadic GCLJ seems closely related to non-ossifying fibroma of long bones, with both lesions sharing MAPK pathway-activating mutations. In this review, we extrapolate from these recent findings to contextualize GCLJ genetics and we highlight the therapeutic implications of this new information. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Spheno-orbital juvenile psammomatoid ossifying fibroma: a case report and literature review.

Ossifying fibroma (OF) is an uncommon benign fibro-osseous lesion. Based on its clinical, morphological, and radiological features, OF is further divided into cemento-ossifying fibroma (COF), juvenile psammomatoid ossifying fibroma (JPOF), and juvenile trabecular ossifying fibroma (JTOF). JPOF rarely involves the cranial base, with limited reports published on spheno-orbital JPOF. In this paper, we report a case of JPOF of the greater wing of the sphenoid bone and lateral orbital wall in an 11-year-old child and show a surgical video. Although rare, JPOF should be considered in the differential diagnosis of fibro-osseous lesions of the spheno-orbital region.

Malignant phosphaturic mesenchymal tumor-ossifying fibroma-like subtype: a case report and literature review.

BACKGROUND: A phosphaturic mesenchymal tumor (PMT) is classified into four histological subtypes: mixed connective tissue, osteoblast-like, non-ossifying fibroma-like, and ossifying fibroma-like. The ossifying fibroma-like subtype being extremely rare. Most PMTs are benign, with a minimal number becoming malignant after recurrence. In this study, we report a case of recurrence and malignant transformation of PMT-ossifying fibroma-like subtype in the left hip bone. CASE PRESENTATION: Here, we report the clinical manifestations, histology, pathological features, and treatment of a 57-year-old Chinese woman with a recurrent and malignant ossifying fibroma-like subtype PMT of the left iliac bone. The tumor was first discovered 3 years ago when the patient underwent surgery to remove the tumor. Precisely 2 years and 6 months after the operation, the pain in the left hip reappeared. After 6 months, the patient went to our hospital for treatment. After the tumor resection, the postoperative symptoms improved significantly, and the serum alkaline phosphatase level returned to normal. Based on clinical manifestations, evaluation of serum biochemical indicators, X-ray examination, computerized tomography scan of the pelvis, and histopathological examination of the two operations, the patient was finally diagnosed with a recurring and malignant transformation of the left iliac bone phosphaturic mesenchymal tumor-ossifying fibroma-like subtype. No tumor recurrence was found during the follow-up 15 months after the operation. CONCLUSIONS: This case increases the awareness of a rare malignant subtype of PMT and provides a valuable reference for the diagnosis of this disease.

Juvenile psammomatoid ossifying fibroma.

Juvenile psammomatoid ossifying fibroma (JPOF) is an uncommon benign and locally aggressive tumor. We report an unusual head tumour with extremely rare extensiveness and aggressivness. The patient was 18-year-old female with three-day-lasting headache and repetitive oral bleeding. Computed tomography revealed a large, well-circumscribed, expansile mass occupying ethmoid cells, nasal cavities and ventral part of the sphenoid sinus, with extention into the anterior cranial fossa. Pterional craniotomy was carried out. On one-year follow-up recurrence of the lesion was identified and the second surgery was performed. The lesion is under supervision now, due to incomplete removal.

Concomitant bilateral mandibular cemento-ossifying fibroma and cementoblastoma: case report of an extremely rare occurrence.

BACKGROUND: Cemento-ossifying fibroma (COF) and cementoblastoma (CB) are rare benign odontogenic tumors with a predilection for the mandible. Cemento-ossifying fibroma is a fibro-osseous lesion that originates in the tooth bearing areas of jaw and shows cementum-like tissue in a fibrotic stroma. Cementoblastoma is classically related to roots of teeth with the presence of calcified cementum-like material. To date, only a single case of concomitant unilateral COF and CB has been reported in the literature. CASE PRESENTATION: We present an unusual case of a 37-year-old female who presented with two discrete bilateral swellings in the right and left mandible for 10 years. The larger tumor involved the left posterior mandible with extension anteriorly to the left and right anterior mandibles, and the smaller tumor was present in right posterior mandible. Radiology revealed two distinct lesions involving both sides of mandible. Histopathological examination showed characteristic features of cemento-ossifying fibroma in sections of the larger tumor and cementoblastoma in sections of smaller tumor. CONCLUSION: This case shows the very unique bilateral co-existence of COF and CB, the second case reported in literature to date.

A Clinical Audit of Histopathologically Diagnosed Ossifying Fibroma of the Jaws in a Nigerian Population.

BACKGROUND: Ossifying fibroma (OF) is a benign tumor of the jaws, which belongs to the group of fibro-osseous lesions, and exhibits slowly progressive growth leading to jaw expansion with well-defined borders. OBJECTIVE: To evaluate the clinical and radiological characteristics of OFs and their treatment. MATERIALS AND METHODS: A 5-year retrospective study was done. The case notes of subjects were retrieved, analyzed, and evaluated. Relevant information about patients was categorized into bio-data, clinical, and radiological. The diagnosis of lesion was made histopathologically by the oral pathologist. RESULTS: Forty- five patients' case notes were retrieved and analyzed and the patients' age ranged from 2 to 70 years (mean 29.4 ± 16.9). Majority of the patients (55.5%; P = 0.23) were 10-29 years. There were 16 (35.6%) males and 29 (64.4%) females giving a male: female ratio of 1:1.8 (P = 0.01). The cross-sectional dimension of the tumors measured vertically and horizontally ranges from 1 cm2 to 420 cm2 (mean = 54.7 cm2 ± 82.9). There were 60% in the maxilla and 40% in the mandible (P = 0.014). Most of the lesions (68.9%; P = 0.01) showed patchy opacity and cotton wool appearances. Majority of the lesions were extirpated by enucleation alone (P = 0.01). CONCLUSION: The prevalence of OF among the fibro-osseous lesions was 51.0% while against other benign lesions, it was 16.0%. In conclusion, contrary to most other reports across the globe, this lesion in southeast Nigeria occurred more frequently in the maxilla than mandible.

Activating mutations in the MAP-kinase pathway define non-ossifying fibroma of bone.

Non-ossifying fibroma (NOF), which occasionally results in pathologic fracture, is considered the most common benign and self-limiting lesion of the growing skeleton. By DNA sequencing we have identified hotspot KRAS, FGFR1 and NF1 mutations in 48 of 59 patients (81.4%) with NOF, at allele frequencies ranging from 0.04 to 0.61. Our findings define NOF as a genetically driven neoplasm caused in most cases by activated MAP-kinase signalling. Interestingly, this driving force either diminishes over time or at least is not sufficient to prevent autonomous regression and resolution. Beyond its contribution to a better understanding of the molecular pathogenesis of NOF, this study adds another benign lesion to the spectrum of KRAS- and MAP-kinase signalling-driven tumours. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Non-ossifying fibroma: A RAS-MAPK driven benign bone neoplasm.

Non-ossifying fibroma (NOF) has been an intriguing entity since its first description. It is the most common bone tumour, is usually asymptomatic affecting children and adolescents, is composed of a heterogeneous cell population, and undergoes spontaneous regression after puberty. In a recent article in The Journal of Pathology, Baumhoer and colleagues demonstrate mutations activating the RAS-MAPK pathway (KRAS, FGFR1 and NF1) in ∼80% of the tumours. Activation of the RAS-MAPK pathway by somatic mutations is found in a plethora of tumour types, both benign and malignant, while germline mutations cause a wide range of syndromes collectively termed the RASopathies. Their findings indicate that NOF, for long thought to be reactive, should be considered a true neoplasm. Moreover, their data suggest that only a subset of cells in the lesion contain the mutation. A second cell population consisting of histiocytes and osteoclast-like giant cells appears to be reactive. This intimate relation between WT and mutant cells is also frequently encountered in other benign and locally aggressive bone tumours and seems essential for tumourigenesis. The spontaneous regression remains enigmatic and it is tempting to speculate that pubertal hormonal signalling, especially increased oestrogen levels, affect the balance between mutant and WT cells. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Juvenile Psammomatoid Ossifying Fibroma of the Orbital Roof: A Rare Cause of Proptosis among Children.

INTRODUCTION: Juvenile psammomatoid ossifying fibroma (JPOF) is a rare bone tumor characterized by a predilection for the sinonasal region and a tendency to affect younger patients, with a potential for aggressive growth and high recurrence (30-56%). JPOF warrants complete surgical resection to avoid recurrence. CASE PRESENTATION: In this article, we report a young boy who presented with unilateral prop-tosis with an expansile bony tumor with ground glass appearance involving the left frontal bone and orbital roof on his images. Complete surgical resection was done, and histopathological examination revealed JPOF with abundant psammomatoid bodies. DISCUSSION: This patient is a rare case of neurocranial JOPF and adds new features to the typical features already described for JPOF.

SATB2 is frequently expressed in ossifying and non-ossifying peripheral oral fibroma of the gingival region but not in reactive fibromatous lesions from other intraoral sites.

Ossifying and non-ossifying peripheral oral fibromas (POF) of the gingival and alveolar mucosa are localized, cellular, small fibrous nodular lesions likely resulting from diverse external/ internal physical and chemical irritation or injuries. A central nidus of metaplastic woven bone characterizes and defines the ossifying variant. The inherent tendency of these lesions to ossify remains elusive. We herein analyze SATB2 expression as osteoblastic transcription and differentiation factor in 28 gingival POFs (10 of them ossifying) and compare them to 28 fibrous lesions from different non-gingival intraoral sites. Strong to moderate diffuse nuclear SATB2 immunoreactivity was detected in all ossifying (10/10; 100%) and in 8/18 (44%) non-ossifying gingival POFs, but in only 1/28 (3%) non-gingival oral reactive nodular fibrous lesions. This study illustrates for the first-time consistent expression of the osteoblastic marker SATB2 in ossifying and most of non-ossifying POFs of the gingival area but lack of this marker in reactive fibrous lesions from other oral cavity sites. This finding is in line with the proposed origin of gingival POFs from periodontal ligaments and may explain the frequent ossification observed in them. It is mandatory to consider this finding when assessing biopsies from SATB2-positive oral cavity neoplasms to avoid misinterpretation.

Benign oral mucosal lesions: Clinical and pathological findings.

A diverse spectrum of benign oral mucosal lesions exists, presenting as either isolated oral findings or in association with dermatologic conditions. Oral lesions can closely resemble one another; therefore, it is important for clinicians to be able to recognize their distinctive features, to be able to recognize benign versus malignant disease, and to recognize when obtaining a biopsy specimen is warranted. The first article in this continuing medical education series reviews oral anatomy, the clinical attributes of several benign lesions of the oral cavity, and appropriate management and therapeutic modalities.

Bringing benign ectomesenchymal odontogenic tumours to the lab: An in vitro study using an organotypic culture model.

BACKGROUND: Benign neoplasms exhibit most of the cellular phenomena considered hallmarks of cancer, except the capacity to metastasize. Thus, the elucidation of the mechanisms associated with the progression of benign neoplasms may complement and clarify the mechanisms involved in carcinogenesis. Benign odontogenic tumours often result in facial deformities and morbidities, and have complex pathogenesis, mainly due to the diversity of interactions between the odontogenic epithelium and the ectomesenchyme. Primary cell culture of such tumours is not only difficult to be established and maintained, but also tumour cells lose characteristic cellular morphology. Considering gene expression, growth, migration, proliferation and cellular morphology are controlled by cell-cell interactions and cell-extracellular matrix interactions, cell culture in 3D substrates has gained space as a way to overcome some of the limitations of traditional monolayer cell culture systems. METHODS: In this study, fragments obtained from mesenchymal odontogenic tumours were cultured in type I collagen scaffolds. Invasion tests were performed in these models, as well as phenotypic characterization of the cultured tumours. RESULTS: The results obtained for the odontogenic myxoma and the cemento-ossifying fibroma demonstrate a good reproduction of the growth pattern of these tumours under ex vivo conditions. Microscopic evaluation showed maintenance of cell viability in the explants for more than 30 days, without the presence of necrosis. CONCLUSION: This is the first study involving long-term 3D primary cultures of benign odontogenic tumours, which is expected to support complex approaches to cell and molecular biology, and to serve as an experimental model for testing molecular therapies.