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Background: This systematic review aimed to incorporate published data regarding synchronous cemento-ossifying fibromas (COF), with an analysis of their demographic and clinicopathological characteristics., Material and Methods: Case reports and case series of synchronous COF were searched in PubMed, Web of Science, Scopus, EMBASE, and LILACS according to the PRISMA (2020) statement. Also, a manual search was carried out and the grey literature was assessed. A descriptive statistical analysis was performed., Results: Nineteen studies comprising 20 cases of synchronous COF were included. The mean age at diagnosis was 35 years (±13.8), with a predominance of female patients (n=12/60%). In 13 cases (65%) the mandible and the maxilla were affected simultaneously. In two cases (10%) first-degree relatives (parents or siblings) had been previously diagnosed with COF. The diagnostic hypotheses were reported in 8 cases (40%), with florid cemento-osseous dysplasia, ameloblastic fibroodontoma, calcifying cystic odontogenic tumor, osteoma and cementoblastoma being cited in the differential diagnosis. Among the cases with details about management (n=17), eleven were treated by surgical enucleation and/or excision (64.7%). Follow-up was provided for 10 cases (50%), with a mean period of 44.7±62.19 months. Recurrence occurred in three of informed cases., Conclusions: Synchronous manifestation of COF is rare. Female patients around the 3rd decade of life are more commonly affected. Bilateral involvement of the mandible and maxilla is the most common clinical presentation.

Abstract: Hybrid tumors are rare lesions having features of multiple diseases in one lesion. A hybrid tumor of central giant cell granuloma (CGCG) and central ossifying fibroma (COF) shows the presence of microscopically large areas with CGCG character and large areas with COF features inside a single clinical lesion, separated by a transition zone. A rare type of COF is juvenile ossifying fibroma (JOF)-trabecular variant in the mandible. We present a unique and rare case of a hybrid tumor of the CGCG-JOF-trabecular variant in the mandible of a 14-year-old female which initially diagnosed with CGCG. The ambiguous pathogenesis of hybrid tumors and giant cells is reviewed. The goal of this article is to highlight the importance of careful clinical, radiological, and histopathological examination of each case to prevent misdiagnoses and recurrences. Similar and other cases must be reported in order to better understand the interrelationship between these hybrid lesions and their biological behavior., (Copyright © 2023 Copyright: © 2023 Indian Journal of Pathology and Microbiology.)

Background: Indistinct and analogous histopathological features of various fibro-osseous lesions make establishing a definitive diagnosis a challenge. There is a need for additional molecular and histochemical tools to support and differentiate these lesions in order to establish a concrete diagnosis., Materials and Methods: A retrospective analysis of biopsied lesions in formalin-fixed paraffin-embedded sections (10 cases each of fibrous dysplasia, ossifying fibroma, and cement-osseous dysplasia) retrieved from the archives was studied for immunoexpression of osteocalcin (quantitative analysis in osteocytes), collagen characterization using Azan, Picrosirus, and Toluidine blue stain for evaluating intensity and localization of collagen fibers, and morphometric analysis of vasculature (for evaluating mean vessel density as square microns)., Results: Positive immunostaining of osteocalcin suggested mutations of the GNAS-1 gene found in fibrous dysplasia indirectly, as it is a negative regulator of bone formation. Osteocalcin immunopositivity was quantitatively measured in the fibro-osseous lesions, with fibrous dysplasia measuring 14.47 ± 3.628 as compared to ossifying fibroma measuring 5.23 ± 1.33, followed by cemento-osseous dysplasia measuring 2.30 ± 1.409. Toluidine blue suggests the presence of oxytalan fibers (resistant to acid hydrolysis) in ossifying fibroma and cemento-osseous dysplasia, pointing toward the pathogenesis of the lesion. Azan stain and Picrosirus (under a polarizing microscope) helped in distinguishing hard tissue characteristics (70% of cases of fibrous dysplasia showed only a magenta component followed by intermixed magenta with a blue component in 20% of cases and only 10% of cases showed magenta with blue borders whereas for ossifying fibroma, 40% of cases depicted magenta with blue borders along with the other 40% with intermixed magenta with blue component). The mean vessel density was also highest in fibrous dysplasia measuring 7.90 ± 1.079 (in Sq. micron area), followed by ossifying fibroma and cemento-osseous dysplasia., Conclusion: The diagnosis of fibro-osseous lesions by hematoxylin and eosin alone is confusing and thus should be supported by relatively simple histomorphometric analysis for better treatment outcomes. At the diagnostic stage of fibro-osseous lesions, evaluation of intralesional vessel size, reliable molecular marker, and histochemical nature can aid in differentiating fibrous dysplasia from central ossifying fibroma and cemento-osseous dysplasia alongside, other clinical, radiographic and pathological criteria. These parameters help in the diagnostic decision-making of fibro-osseous lesions., (Copyright © 2024 Copyright: © 2024 Indian Journal of Pathology and Microbiology.)

Abstract: Ossifying fibromyxoid tumor (OFMT) is a rare mesenchymal tumor of uncertain histogenesis with intermediate malignant potential presenting commonly in the fifth to sixth decade in the proximal limb and limb girdle. A 65-year-old male patient presented with a slow-growing gluteal mass. Wide local excision performed showed a well-defined tumor in the subcutaneous plane with a partially hard outer shell. Microscopy showed a moderately cellular tumor having cords and nests of round to ovoid cells with moderate cytoplasm and bland nuclei embedded in a myxo-hyaline matrix. An incomplete peripheral rim of ossification was seen. Pleomorphism/high cellularity was not seen. Mitosis was <2/50 high-power field. On immunohistochemistry, both S100 and desmin were positive. A diagnosis of typical OFMT was rendered. Even though rare with many morphological mimics, OFMT should be diagnosed with precision as most of these tumors are low-grade tumors that require only wide local excision and close follow-up without any adjuvant therapy., (Copyright © 2023 Copyright: © 2023 Indian Journal of Pathology and Microbiology.)

Introduction: Peripheral ossifying fibroma (POF) is a solitary gingival growth thought to arise from the gingiva, periosteum or the periodontal ligament. It is a slow-growing, benign, progressive lesion that is limited in size., Case Description: This article describes a case of ossifying fibroma of a peripheral variant that occurred in a 26-year-old female in the anterior region of the lower jaw and presented as a growth on the gingiva. Since it was difficult to diagnose clinically, a pathological evaluation was mandatory. Upon pathological confirmation of the diagnosis, the lesion was surgically excised up to the periosteum. This was deemed to be the required treatment yet, since the recurrence rate is high for POF (8% to 20%), the patient must be followed up yearly to check for recurrence., Competing Interests: All authors declare that there are no competing interests (financial or professional) that may be perceived to influence the research conducted., (Copyright © 2024 CDHA | ACHD.)

Objectives: Gingiva is one of the supporting tissues around the teeth that can be affected by various neoplastic or nonneoplastic lesions. Previous studies have examined several types of gingival lesions, but the lack of a standardized classification system has hindered meaningful comparisons. Additionally, many studies focused primarily on reactive lesions. Our study aims to contribute to the understanding of gingival lesions by investigating their prevalence across age groups, genders, sites, and by their clinical presentation. This research could lead to improved diagnostic accuracy and treatment strategies., Materials and Methods: This retrospective study explores the prevalence of gingival lesions based on biopsies during a 22-year span. The patient's demographic details, including age, gender, and lesion's clinical presentation were systematically collected. These lesions were categorized into six groups. Descriptive statistics, χ 2 test of independence, and one-way ANOVA were used for data analysis., Results: Among the 7668 biopsied lesions, 684 (8.9%) lesions were located in the gingiva, with a greater occurrence in women (63.5%). Soft tissue tumors represented the most prevalent group in the gingival lesions (72.1%), and peripheral giant cell granuloma (PGCG) was the most frequent lesion (21.2%), followed by, pyogenic granuloma (19.3%), peripheral ossifying fibroma (17.8%) and focal fibrous hyperplasia (7.6%); all of which predominantly affected women, with mean ages falling in the fourth decade of life. Squamous cell carcinoma was recognized as the most common malignancy., Conclusion: In this study, PGCG was found to be the most common lesion in the gingiva in Iranian population. Further analysis using a unanimous categorization is required to confirm these results., (© 2024 The Authors. Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)

Background: Peripheral ossifying fibroma is a nonneoplastic inflammatory hyperplasia that originates in the periodontal ligament or periosteum in response to chronic mechanical irritation. Peripheral ossifying fibroma develops more commonly in young females as a solitary, slow-growing, exophytic nodular mass of the gingiva, no more than 2 cm in diameter. While various synonyms have been used to refer to peripheral ossifying fibroma, very similar names have also been applied to neoplastic diseases that are pathologically distinct from peripheral ossifying fibroma, causing considerable nomenclatural confusion. Herein, we report our experience with an unusual giant peripheral ossifying fibroma with a differential diagnostic challenge in distinguishing it from a malignancy., Case Presentation: A 68-year-old Japanese male was referred to our department with a suspected gingival malignancy presenting with an elastic hard, pedunculated, exophytic mass 60 mm in diameter in the right maxillary gingiva. In addition to computed tomography showing extensive bone destruction in the right maxillary alveolus, positron emission tomography with computed tomography revealed fluorodeoxyglucose hyperaccumulation in the gingival lesion. Although these clinical findings were highly suggestive of malignancy, repeated preoperative biopsies showed no evidence of malignancy. Since even intraoperative frozen histological examination revealed no malignancy, surgical resection was performed in the form of partial maxillectomy for benign disease, followed by thorough curettage of the surrounding granulation tissue and alveolar bone. Histologically, the excised mass consisted primarily of a fibrous component with sparse proliferation of atypical fibroblast-like cells, partly comprising ossification, leading to a final diagnosis of peripheral ossifying fibroma. No relapse was observed at the 10-month follow-up., Conclusions: The clinical presentation of giant peripheral ossifying fibromas can make the differential diagnosis from malignancy difficult. Proper diagnosis relies on recognition of the characteristic histopathology and identification of the underlying chronic mechanical stimuli, while successful treatment mandates complete excision of the lesion and optimization of oral hygiene. Complicated terminological issues associated with peripheral ossifying fibroma require appropriate interpretation and sufficient awareness of the disease names to avoid diagnostic confusion and provide optimal management., (© 2024. The Author(s).)

Cemento-ossifying fibroma (COF) is a mesenchymal benign odontogenic tumor, which may lead to impacted or ectopic permanent teeth. Autotransplantation of teeth is a surgical process, in which a tooth is transplanted from one position to another in the same individual. This method can effectively restore the patient's mastication and aesthetics and is feasible in replacing missing teeth. This study reports a case of simultaneous COF resection combined with heterotopic canine autotransplantation to repair dentition defect, which effectively promotes the restoration of bone continuity and stability and achieves immediate and long-term aesthetic function requirements.

Introduction: Ossifying fibromas are rare, non-aggressive benign tumours of the bone, commonly involving the posterior mandible in middle-aged individuals with a female predilection., Findings: Clinical manifestations include asymptomatic expansion of the mandible with infrequent maxillary lesions, pain, malocclusion, and compromised quality of life including aesthetic perception. Owing to multiplicity of features, tendency of recurrence, and possibility of malignant transformation, the diagnosis, treatment, and post-operative management of ossifying fibroma are always a challenge., Takeaway Lessons: Study aims to report a clinical case of extensive swelling involving the coronoid process and condyle on the right side to crossing the mid-line of the mandible with compromised functions and aesthetics. The article describes the clinical, histopathological, and radiological features of the case. The possible treatment and challenges encountered are discussed., (Copyright © 2024 Copyright: © 2024 Indian Journal of Dental Research.)

Cemento-ossifying fibroma (COF) and juvenile ossifying fibroma (JOF) have been considered distinct entities within the category of fibro-osseous lesions. This study aimed to assess osteoblast and osteoclast activity in COF and JOF by investigating bone resorption markers, specifically receptor activator of nuclear factor-kB (RANK), RANK ligand (RANKL), and its inhibitor osteoprotegerin (OPG). A comparative analysis of these markers was performed on all lesions. Immunohistochemistry was employed to evaluate and quantify the expression of these biomarkers in a sample of 20 cases of cemento-ossifying fibroma (COF), 15 cases of psammomatoid juvenile ossifying fibroma (PsJOF), and 10 cases of trabecular juvenile ossifying fibroma (TrJOF). The expression of osteoprotegerin was significantly higher in cemento-ossifying fibroma (33.9±13.0) compared to trabecular juvenile ossifying fibroma (27.3±9.2) and psammatoid ossifying fibroma (25.2±14.9), with the COF showing the highest expression followed by the latter two (p=0.037). There was a higher percentage (80%) of stromal fibroblast cells that showed positive expression of RANKL in cemento-ossifying fibroma (COF) compared to psammomatoid juvenile ossifying fibroma (PsJOF) (33.3%) and trabecular juvenile ossifying fibroma (TrJOF) (30.0%) when considering a positive expression score of 3 (p=0.024). Cemento-ossifying fibroma demonstrated the highest expression of osteoprotegerin and RANKL-positive stromal fibroblast cells, followed by psammomatoid juvenile ossifying fibroma and trabecular juvenile ossifying fibroma. These findings provide valuable insights into the pathogenesis of these lesions., Competing Interests: The author declares no conflict of interest., (©2023 JOURNAL of MEDICINE and LIFE.)

Background: Ossifying fibroma (OF) of the craniofacial skeleton is a fibro-osseous lesion characterized by various patterns of bone formation in a cellular fibroblastic stroma. The molecular landscape of OF remains mostly unknown. There are a few known pathogenic abnormalities in OF, including HRPT2 mutations in conventional OF and SATB2 translocations in juvenile psammomatoid OF. On the other hand, conflicting reports exist regarding MDM2 gene amplification and chromosomal copy number alterations (CNA) in OF., Methods: Surgically removed biopsies and curettage specimens from OF patients were obtained. Clinical, radiographic, and pathologic features of tumors were reviewed. Genomic DNA was extracted from formalin-fixed, paraffin-embedded blocks of tumor tissue. Capture-based DNA next-generation sequencing targeting the coding regions 529 cancer genes and select introns was performed., Results: We identified 17 OF cases from 8 male and 8 female patients with mean age of 22 years (range 1-58 years). Nine case occurred in the gnathic bones and 8 in the extragnathic craniofacial bones. These cases included 3 juvenile psammomatoid OF, 6 conventional OF and 8 juvenile trabecular OF. Large-scale CNAs were present in 6 of 17 cases. Seven cases (41%) had focal amplifications including FOSB (n = 2, 11%), FOS (n = 4, 23%), COL1A1 (n = 4, 23%) and TBX3 (n = 5, 29%). Three cases (17%) had pathogenic CDC73 mutations. No cases showed focal MDM2 amplification., Conclusions: Here, we provided a comprehensive molecular characterization of OF that reveals a heterogeneous genetic profile with occasional large-scale CNAs (n = 6, 35%). FOS, FOSB, and TBX3 genes that regulate AP-1 transcriptional complex are frequently altered in OF (n = 7, 41%), chiefly in juvenile trabecular OF. These genes encode transcription factors that act as downstream effectors of the MAP kinase signaling pathway. MDM2 amplification is an exceedingly rare event in OF, if present at all, so identification of this event should continue to raise concern for low-grade gnathic osteosarcoma. In summary, our findings suggest that OF represents a heterogeneous group of tumors at the genetic level but dysregulation of the AP-1 pathway may play a role in pathogenesis of juvenile trabecular OF., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Ossifying fibroma of the paranasal sinuses and skull base in paediatric patients is difficult to operate and can recur easily after surgery. This study aimed to analyse factors associated with recurrence after transnasal endoscopic resection of ossifying fibroma in paediatric patients., Methods: This retrospective observational study included 34 patients under 17 years of age who underwent transnasal endoscopic resection of ossifying fibroma of the paranasal sinuses and skull base from 2005 to 2021 at a single tertiary medical centre. Clinical indicators such as age; surgical history; pathological type; intraoperative bleeding; and orbit, anterior skull base, sphenoid bone, sella turcica, clivus, or frontal sinus involvement were subjected to univariate analysis using the χ 2 test, to investigate whether any of these factors affected recurrence., Results: All 34 patients underwent transnasal endoscopic resection. The follow-up period was 6-120 months (mean: 48.0 months). Five patients experienced local recurrence during the follow-up period (14.7%). Results of χ 2 tests indicated that a history of previous surgery, the amount of intraoperative bleeding, and sphenoid and/or sella turcica and clivus involvement were significantly associated with recurrence (P < 0.05). Age; pathological stage; and orbit, anterior skull base, and frontal sinus involvement were not associated with recurrence (P > 0.05)., Conclusions: The increased risk of recurrence after transnasal endoscopic resection of nasal-skull base ossifying fibroma should be considered during endoscopic surgery in paediatric patients with a history of previous surgery, intraoperative bleeding tendency, and sphenoid and/or sella turcica and clivus involvement. These patients require careful postoperative follow-up., (© 2023. The Author(s).)

Peripheral ossifying fibroma (POF) is a reactive, benign gingival enlargement. Its etiology is not fully known. It can be seen in many different sizes in the mouth. The histopathological appearance of POF is mineralized tissue and fibrous proliferation. All relevant soft and hard tissues must be removed to prevent recurrence. Periodontal tissue remaining after excision is important for tooth preservation. With large lesions, the loss of healthy periodontal tissue is also large. Periodontal surgical approaches are important to preserve the remaining periodontal tissue. The positive effects of autogenously obtained titanium-prepared platelet-rich fibrin (T-PRF) and connective tissue graft (CTG) on soft tissue are well known. A 34-year-old woman presented with a fibrous and pedunculated gingival mass in the upper left canine premolar region. The operation was performed with complete excision of the lesion down to the bone along with the surrounding healthy tissue. Periodontal treatment of the large defect created after excision of a large POF lesion was performed with laterally positioned flap, CTG and T-PRF. The periodontal tissue and defect were noted to heal in a healthy manner at the 6-month follow-up. POF is a benign lesion; however, it has a high recurrence rate. Complete elimination of the lesion is crucial to prevent recurrence. Periodontal surgical methods and biomaterials applied after surgical excision are significant to maintain the periodontal health of the remaining teeth and tissues.

Background: gingival/alveolar mucosal reactive hyperplastic lesions (GRHL), including fibrous hyperplasia (FH), pyogenic granuloma (PG), peripheral ossifying fibroma (POF) and peripheral giant cell lesion (PGCL), are a common group of oral diseases. The aim of the present study was to access the frequency and distribution of the clinical and histological features of these disorders in a Brazilian population., Material and Methods: all specimens diagnosed as GRHL in three Oral Pathology laboratories were selected for the study. Clinical information was retrieved from the laboratory biopsy forms and hematoxylin and eosin stained histological slides were reviewed for analysis of the histological characteristics., Results: final sample was composed of 996 specimens, including 463 FH (47%), 280 PG (28%), 183 POF (18%) and 70 PGCL (7%). Females were more affected by FH, PG, and POF, and most cases affected adults with mean ages ranging from 40 to 53 years. FH, PG, and POF were more common in the upper gingiva/alveolar mucosa. Most PG, POF and PGCL were pedunculated, in contrast with FH (p<0.001). PG, FH and POF were mostly red or normal mucosal in color, while PGCL were mostly red/purple (p<0.001). PGCL were larger, followed by POF, FH and PG (p<0.001). Some histological features were characteristically found in some conditions, but they were also encountered in other lesions with variable frequencies., Conclusions: Oral medicine specialists, oral pathologists and periodontists are usually the professionals in contact with patients presenting GRHL and it is of upmost relevance that they should be familiarized with their clinical and histological profile.

Purpose: Gingival fibromas (GFs) are fibrous lesions of the gingiva that are not well defined in the literature. They are histologically similar to peripheral ossifying fibromas (POFs), both being characterized as cellular proliferations of dense fibrous tissue, with POFs differing in that they demonstrate foci of calcification. This study aims to expand upon the immunohistochemical characterization of GFs, and to confirm their osteoblastic phenotype., Methods: Formalin fixed, paraffin embedded GFs, POFs and fibroepithelial polyps (FEPs) of the gingiva were examined. Immunohistochemical staining was performed for special AT-rich sequence binding protein 2 (SATB2), runt-related transcription factor 2 (RUNX2), osteocalcin and alpha-smooth muscle actin (αSMA). Sections were evaluated by light microscopy and the immunohistochemical staining patterns were assigned immunoreactive scores (IRS) based on percentage of stained cells and intensity of staining., Results: GFs, POFs, and FEPs of the gingiva expressed osteoblastic markers SATB2, RUNX2 and osteocalcin. GFs and POFs expressed αSMA while FEPs of the gingiva did not. GFs and POFs had similar staining patterns of SATB2, RUNX2 and αSMA., Discussion: These findings demonstrate that GFs and POFs exhibit a similar immunohistochemical profile, and supports a theory that GFs are osteoblastic lesions possibly related to POFs., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: To analyze the clinicopathological features of different histological subtypes of epulis, and evaluate the risk factors associated with recurrence., Materials and Methods: A retrospective study including 2971 patients was performed. The patients' sex, age, location, size, histological subtypes, recurrence information, oral hygiene habits, periodontitis symptoms and smoking history were retrieved from the patient medical records and follow-up information., Results: Among the 2971 cases, focal fibrous hyperplasia (FFH) was the most common lesion (60.92%), followed by peripheral ossifying fibroma (POF) (29.32%), pyogenic granuloma (PG) (8.08%) and peripheral giant cell granuloma (PGCG) (1.68%). The peak incidence of epulis was in the third and fourth decade of life, with a mean age of 45.55 years. Female predominance was found in all types of lesions with a female to male ratio of 1.71:1. PG had the highest recurrence rate (17.18%), followed by POF (12.98%), FFH (9.55%) and PGCG (8.82%). Histological subtypes were significantly correlated with the recurrence of epulis (P = 0.013). Regular supportive periodontal therapy (P = 0.050) had a negative correlation with recurrence, whereas symptoms of periodontitis (P < 0.001) had a positive correlation with the recurrence of epulis., Conclusions: Controlling the periodontal inflammation and regular supportive periodontal therapy might help reduce the recurrence of epulis., (© 2023. The Author(s).)

Cemento-ossifying fibroma (COF) is a benign mesenchymal odontogenic tumor that commonly occurs in the tooth-bearing areas of the maxilla and mandible. This study reports a COF case located under the left buccal mucosa. The classification and differential diagnosis of this COF case were discussed based on the diagnosis and treatment of this case and previous literature.

Background: Peripheral Ossifying Fibroma (POF) is a reactive hyperplastic lesion that exclusively occurs in the gingiva and is characterized by the deposition of dystrophic calcification, cementum-like tissue, and immature and mature bone within the connective tissue. The objective of the present study was to perform a retrospective analysis of clinicopathologic features of POF., Material and Methods: Clinical and histopathological data were obtained from biopsy records and histopathological reports from a Brazilian reference service in Oral Pathology (1999 - 2020). Morphological analysis was performed to evaluate features related to the mesenchymal component, inflammatory infiltrate, ulceration, and mineralized tissue., Results: A total of 270 POFs were diagnosed during the study period. A higher frequency was observed in females (71.9%) between the third (22.9%) and fourth (23.3%) decades of life. The anterior upper gingiva (29.1%) was the most affected region. Mature (86.7%) and immature (52.6%) bone tissue were the most frequent. There was a significant association between immature bone deposition and lesions with size ≤ 1.7 cm (p = 0.041); immature bone and cement-like tissue deposition with an evolution time ≤ 16 months (p < 0.001); deposition of immature bone and mesenchymal hypercellularization (p < 0.001); deposition of dystrophic calcification and the presence of ulceration (p < 0.001)., Conclusions: The clinical characteristics corroborate the findings in the literature. The heterogeneous distribution and quantity of mineralized tissues found in the analyzed cases support the theory that the different mineralized tissues constitute a spectrum of clinical maturation of POF.

In the cranio-facial skeleton, a heterogeneous group of well characterized fibro-osseous lesions can be distinguished. Whereas fibrous dysplasia can affect any skeletal bone, ossifying fibroma and cemento-osseous dysplasia exclusively develop in the cranio-facial region, with most subtypes restricted to the tooth bearing areas of the jaws. Herein we present a series of 20 fibro-osseous lesions that developed mostly in the frontal bone and in the mandible, presenting as expansile intramedullary tumors with a unique histologic appearance and an indolent clinical course. We provide evidence that these tumors are distinct from the categories included in the WHO classification and are therefore currently unclassifiable. The definition of cemento-ossifying fibroma as an odontogenic neoplasm developing only in close proximity to teeth should be re-considered and incorporate also extragnathic lesions as shown here., (© 2021. The Author(s).)

Ossifying fibromas of the head and neck region are classified as cemento-ossifying fibroma (COF) (odontogenic origin), and two types of juvenile ossifying fibromas: juvenile trabecular ossifying fibroma (JTOF), and juvenile psammomatous ossifying fibroma (JPOF). The potential for recurrence in JTOF and JPOF and the discovery of newer molecular signatures necessitates accurate histological classification. Over 12 years (2005-2017), a total of 45 patients with 51 tumours were retrieved and reviewed for clinic-pathological features from the archives of a tertiary care oncology centre. Of 45 cases, COF, JTOF and JPOF comprised 13 (28.9%), 11 (24.4%) and 18 (40%) cases respectively. Three cases were unclassifiable. M: F ratio was 1:3.3, 1.1:1, 2:1 for COF, JTOF and JPOF respectively with an age range of 6-66 years (mean: 24.6, median; 18.1 years). The most common site for COF was mandible, for JTOF was maxilla, and for JPOF was ethmoid sinus. One case of mixed JTOF and JPOF histology was seen. Aneurysmal bone cyst-like areas were seen in 26.6% of cases, most commonly in JPOF. Follow up was available in 23 cases, and ranged from 4 to 207 months. Three cases of JPOF had a recurrence and one patient with JTOF had residual disease after surgery. One case of COF demonstrated increased parathyroid hormone levels. COF, JTOF, and JPOF are clinically, radiologically and histologically distinct entities. Surgical resection is the mainstay of treatment. JPOF has a higher incidence of recurrence as compared to JTOF and COF and hence needs a more aggressive follow-up., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Rationale: Several diseases feature tumors, or tumor-mimicking lesions, that further invade the bone and surrounding joints of the wrist region. Here, we describe 3 rare cases of multiple destructed carpal bones and adjacent joints in different disease entities confirmed via pathologic diagnosis., Patient Concerns: All 3 cases were examined between January 2016 and December 2019. Three patients presented with similar clinical manifestations and radiographic features, with multiple osteolytic lesions in the carpal bones and metacarpal bone base., Diagnoses: The 3 cases were diagnosed as diffuse type tenosynovial giant cell tumor, calcifying aponeurotic fibroma, and rheumatoid arthritis., Interventions: Separate, experienced radiologist and pathologist took part in the interpretation and compartmentalization of radiographs and pathological findings, respectively. Even magnetic resonance imaging could not achieve a diagnosis; surgical excision was therefore required, with subsequent pathological assessment for treatment and final diagnosis., Outcomes: functional outcomes also differed among patients, poorest in rheumatoid arthritis patient., Lessons: We report 3 rare disease entities, presenting with multifocal osteolytic lesions in the wrist. They all presented with similar clinical manifestations, and the final diagnoses were made via pathological evaluation. Compared with tenosynovial giant cell tumor and calcifying aponeurotic fibroma, rheumatoid arthritis had the poorest outcome., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: To report the exceptional occurrence of ossifying fibromyxoid tumour (OFMT) as a primary bone lesion. OFMT is a rare soft tissue tumour of uncertain differentiation and variable malignant potential, that occurs in adults with a slight male predominance. It is typically located in the subcutis or in the skeletal muscles of the extremities, followed by trunk or head and neck., Methods: Two cases of OFMT proven to arise from bone are presented. The first is a 65-year old female with a history of rib "osteosarcoma", presenting with an inferior lobe left lung mass. The second is a man with a lytic lesion of the 5th cervical vertebra that recurred shortly after resection. Following H&E and immunohistochemical examination, tumour samples were analysed by NGS and by break-apart FISH to detect rearrangement of the PHF1 and TFE3 genes., Results: PHF1 gene-rearrangement was identified by FISH on both the primary and the metastatic lesion of first patient. NGS identified a PHF1 (intron1) and EPC1 (exon 10) fusion transcript later confirmed by positive PHF1 rearrangement on FISH in the second case., Conclusions: The demonstration of PHF1 gene rearrangements represents a fundamental ancillary diagnostic test when presented with challenging examples of OFMT., (Copyright © 2020 Società Italiana di Anatomia Patologica e Citopatologia Diagnostica, Divisione Italiana della International Academy of Pathology.)

Juvenile ossifying fibromas (JOFs) are a rare group of fibro-osseous lesions, typically of odontogenic origin. Juvenile psammomatoid ossifying fibroma (JPOF) is one variant, that is, histopathologically distinguished by spherical ossicles resembling psammoma bodies. JPOF tumours are most commonly found in craniofacial skeletal structures and can be locally aggressive. Thus, early management by complete surgical excision is crucial for good outcomes, although recurrence is still possible. Secondary aneurysmal bone cyst (ABC) formation has been reported with JOF lesions, but less commonly with the JPOF variant. We describe an unusual case of JPOF that presented in the calcaneus with secondary ABC formation., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Gnathic fibro-osseous lesions are a diverse group of disease processes which share overlapping microscopic features characterized by fibroblastic stroma with variable cellularity and a range of bone forming pathological processes leading to woven, sclerotic and cementum-like structures. Some of the lesions are unique to craniofacial location and a combination of clinical, radiological and pathological correlation is often necessary for diagnostic accuracy. Gnathic osteosarcomas are rare tumors with differences in age distribution and behavior as compared to osteosarcoma of long bones. This review will discuss the clinicopathological and radiological features of gnathic fibro-osseous lesions and osteosarcoma with updates on current genetics and molecular pathogenesis.

Context.—: Ossifying fibromyxoid tumor (OFMT) is a rare, slow-growing mesenchymal neoplasm of uncertain histogenesis with intermediate malignant potential., Objective.—: To highlight the most important diagnostic features, including morphologic, immunohistochemical, and molecular findings; to provide comparisons to other entities in the differential diagnosis; and to provide a summary of the clinical features and outcomes in cases reported to date., Data Sources.—: The data sources include recently published literature encompassing OFMT and tumors in the histologic differential diagnosis, and cases from institutional files., Conclusions.—: Ossifying fibromyxoid tumor is important to recognize because of its low-grade morphology but potential for recurrence and metastasis. Recent molecular analysis has expanded the morphologic spectrum of OFMT, with additional cases discovered that are enriched for aggressive behavior. The diagnosis can often be rendered through a combination of morphology and coexpression of S100 protein and desmin, although only a minority of cases described contain all of these primary features. In cases that do not have all of these features, a high index of suspicion guided by morphology and exclusion of other tumors in the histologic differential diagnosis can lead to the correct diagnosis. Growing access to molecular genetic testing will become increasingly important for correct diagnosis of tumors at the ends of the morphologic spectrum.

Benign fibro-osseous lesions (BFOLs) are a particularly challenging set of diagnoses for the pathologist. This diverse collection of diseases includes fibrous dysplasia, ossifying fibroma and cemento-osseous dysplasia. While all three conditions have similar microscopic presentations, their treatment and prognosis differ, demanding an accurate and definitive diagnosis. A practical and systematic approach considering the patient's history, demographics, intraoperative presentation, and gross appearance with an emphasis on radiology and histology will be discussed.

Ossifying fibromyxoid tumour (OFMT) is a rarely occurring soft tissue neoplasm of mesenchymal origin. It is a rarely found tumour with intermediate behaviour and differentiation. Although it is mostly benign, malignant variants also exist. We are presenting a case of 32-year-old man presented in clinic with complaints of painless swelling in left distal thigh. After reviewing his X-ray, a diagnostic biopsy was planned which came out to be suspicious of solitary fibrous tumour. Other radiological workup was done and the patient was planned to undergo wide margin excision. The final histopathology showed a diagnosis of OFMT of soft tissue, atypical variant. The patient is under follow-up and is disease free. This type of tumour possesses potential of local recurrence and metastases; therefore, it is important to keep a long-term follow-up of patient., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Reactive hyperplastic lesions develop in response to a chronic injury simulating an exuberant tissue repair response. They represent some of the most common oral lesions including inflammatory fibrous hyperplasia, oral pyogenic granuloma, giant cell fibroma, peripheral ossifying fibroma, and peripheral giant cell lesions., Objective: The incidence of those lesions was investigated in an oral pathology service, and the clinical characteristics, associated etiological factors, concordance between the clinical and histopathological diagnostic was determined., Methods: A total of 2400 patient records were screened from 2006 to 2016. Clinical features were recorded from biopsy reports and patients' files., Results: A total of 534 cases of reactive hyperplastic lesions were retrieved and retrospectively studied, representing 22.25% of all diagnoses. The most frequent lesion was inflammatory fibrous hyperplasia (72.09%), followed by oral pyogenic granuloma (11.79%), giant cell fibroma (7.30%), peripheral ossifying fibroma (5.24%), and peripheral giant cell lesions (3.55%). Females were predominantly affected (74.19%), the gingiva and alveolar ridge were the predominant anatomical site (32.89%), and chronic traumatism was presented as the main etiological factor. The age widely ranges from the 1st decade of life to the 7th. Clinically, the reactive hyperplastic lesions consisted of small lesions (0.5-2cm) and shared a strong likeness in color to the oral mucosa. The concordance between the clinical and histopathological diagnostic was high (82.5%)., Conclusion: Reactive hyperplastic lesions had a high incidence among oral pathologies. The understanding of their clinical features helps to achieve a clearer clinical and etiological diagnosis, and the knowledge of factors related to their development. This may contribute to adequate treatment and positive prognosis., (Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.)

Ossifying fibromas are mainly found in the mandible and maxilla. Reports of them arising in the ethmoid sinuses and orbits are rare. We present a case of an otherwise healthy 20-year-old man with gradual onset of right visual disturbance signified by right relative afferent pupillary defect due to a large unilateral ossifying fibroma arising from the ethmoid sinus compressing the medial half of the right orbit. We emphasise the multidisciplinary combined endoscopic endonasal and external approach to ensure a successful debulking of the fibroma.

Background: Reactive localized hyperplastic lesions of the oral cavity (RHLs) are relatively common peripheral lesions which present as a range of clinically similar lesions at dental centers. Diagnosis can be challenging if dentists are unfamiliar with their clinicopathological across various populations., Objective: This study reviews the pattern of distribution of RHLs of the oral mucosa in a hospital- the Obafemi Awolowo University Teaching Hospital Complex (OAUTHC), Ile-Ife., Materials and Methods: We reviewed 10 years data from the archives of the Department of Oral Maxillofacial Surgery and Oral Pathology, Obafemi Awolowo University, Nigeria. Information on RHLs were extracted and recorded on standardized data forms and analyzed using STATA., Results: The most common lesions were pyogenic granuloma (43.7%) and focal fibrous hyperplasia (39.7%), respectively. RHLs were found to be more frequent in women (66.7%) than men (33.3%). The most common locations of involvement was the gingivae (84.6%), and lesions were more common in the 9-29 year age group and the mean age was 37.7 (±21.1) years. The relationship between age group and reactive lesions was however not statistically significant., Conclusion: The major benefit of this study is an improved knowledge of the frequency and distribution of oral reactive lesions in sub-Saharan Africa which may be highly beneficial when establishing a diagnosis and treatment plan in clinical practice.

Background: Identification and differentiation of stromal hard tissue components is a challenging task. Numerous methods of demonstrating these components have been worked upon in the past. Although some of the methods have been successful, there are many drawbacks of employing them. The need of the hour, therefore is to develop and use a simple, rapid and cost-effective method of identifying stromal hard tissues as they may signify an important change in the diagnosis of the pathology. Our aim is therefore to observe the usability of tetrachromic VOF stain over Hematoxylin and Eosin and Masson's Trichrome in routinely encountered head and neck pathologies., Materials and Method: Routine cases such as Central and peripheral ossifying fibromas, osteomas, giant cell granulomas, osteomyelitis and malignancies like osteosarcomas were retrieved from the department archives and 3 sections from each block were prepared to stain with H and E, Masson's trichrome and modified tetrachromic VOF stains respectively using standard staining protocol., Results: Tetrachromic VOF takes an upper hand in stromal hard tissue differentiation irrespective of the pathology., Conclusion: Modified tetrachromic VOF is simple, cost-effective method and can be employed for diagnosis of cases with hard tissue differentiation within the stroma on routine basis., Competing Interests: None

Rationale: Ossifying fibroma (OF) is a benign fibro-osseous lesion that can develop in the oral and maxillofacial region. OF is more common in females and has a marked predilection for the mandible, occurring rarely in the maxilla. Lesions grow slowly and are usually asymptomatic until growth produces an obvious swelling, pain, paresthesia, and facial deformity. With low rates of recurrence, treatment is usually curettage or resection. Very large lesions that invade other organs and that cannot be completely removed should be excised conservatively., Patient Concerns: We present a case of a 46-year-old female with a very large fibro-osseous lesion arising from the maxilla who was more concerned about the facial appearance and requested conservative treatment for economic reasons., Diagnoses: The pathological results based on conservative excision of the lesion confirmed the diagnosis of OF., Interventions: We chose conservative excision via the Weber-Ferguson approach and followed up every 6 months. Facial deformity correction was performed 2 years postoperatively and right lower eyelid ectropion correction 3 years after the primary excision., Outcomes: The ectropion deformity in the right lower eyelid improved dramatically with a better facial appearance and no obvious swelling., Lessons: Treatment programs for OF should be individualized based on the size, growth rate, invasion, and interference with facial function and esthetics. If lesions grow slowly, we suppose that it is feasible to excise conservatively when reconstruction cannot be performed due to esthetic and functional problems. Also regular postoperative follow-up is necessary to detect recurrence, and to improve facial appearance as required.

Ossifying fibroma (OF) is classified as, and behaves like, a benign bone neoplasm. It is often considered to be a type of fibro-osseous lesion (FOL). It can affect both mandible and the maxilla, particularly the mandible. This bone tumour consists of highly cellular, fibrous tissue that contains varied amounts of bone or cementum resembling calcified tissue. Present case is an unusual report of central ossifying fibroma involving the left side of mandible in an 18 year old female patient, who presented to the department with a painless hard swelling. The lesion was treated by surgical resection and reconstruction., Competing Interests: The authors declare no competing interests.

We describe the first case of diagnosis of generalized calcifying aponeurotic fibroma in 52 year-old man receiving long-term therapy for seronegative rheumatoid arthritis with rheumatoid nodules. The prevalence of lesions (presence of multiple subcutaneous nodules in the aponeuroses and fascia of the head, neck, trunk, upper and lower extremities with massive deposition of calcium salts), and a combination with monoclonal secretion (IgGκ serum, BJκ in the urine), raised inflammation markers, suggest that this case of the disease is unique, so both in domestic and foreign literature contains no description of this unusual course of this type of mesenchymal tumor. We have shown that subcutaneous nodules biopsy followed by morphological and immunohistochemical study is required in the diagnosis of the disease. We have given the literature data on the clinical manifestations, methods of diagnosis and differential diagnosis of this disease with a variety of pathologies, accompanied by the development of multiple calcification.

Background: Ossifying fibromyxoid tumor of soft parts (OFMT), is a rare but morphologically distinctive neoplasm of uncertain histogenesis that most frequently affects middle-aged male adults. Clinically, it usually presents as a slowly enlarging, small, circumscribed mass, which in most cases is painless. OFMT is most frequently found within the subcutaneous tissues of extremities or trunk, and rarely in the oral/head and neck region. We present an unusual case of this tumor in the submandibular region, and, based on the current medical literatures this is probably the first case described in this anatomical location., Case Presentation: A 32-year-old male presented to our outpatient clinic with a right submandibular mass with 1-year of evolution. Excisional biopsy showed that it was characterized by ossification along the periphery of the lesion. The neoplastic cells were spindle-like with scant eosinophilic cytoplasm. These cells were arranged with uniform cell-to-cell space in a fibromyxoid stroma. Small and large clusters of calcifications were present within the tumor. Immunohistochemically, the case showed positive staining of S-100 protein, vimentin, nestin, calponin, SMA, GFAF, desmin, INI-1, caldesmon, and CD34. It also showed negative staining of CK, CK7, CK8/18, NF, and EMA. About 2% of neoplastic cells showed positive staining of Ki67. Based on these features, the final pathological diagnosis was OFMT., Conclusions: It is hoped that a greater understanding of OFMT in the head and neck region will avoid potential misdiagnosis, and contribute to determining the correct management, which appears to be complete surgical excision with close follow-up for recurrence surveillance.

Ossifying fibroma (OF) is a rare benign tumor of the craniofacial bones that can reach considerable and disfiguring dimensions if left untreated. Although the clinicopathological characteristics of OF are well established, the underlying etiology has remained largely unknown. Our work indicates that Men1-a tumor suppressor gene responsible of Multiple endocrine neoplasia type 1-is critical for OF formation and shows that mice with targeted disruption of Men1 in osteoblasts (Men1 Runx2Cre ) develop multifocal OF in the mandible with a 100% penetrance. Using lineage-tracing analysis, we demonstrate that loss of Men1 arrests stromal osteoprogenitors in OF at the osterix-positive pre-osteoblastic differentiation stage. Analysis of Men1-lacking stromal spindle cells isolated from OF (OF-derived MSCs (OFMSCs)) revealed a downregulation of the cyclin-dependent kinase (CDK) inhibitor Cdkn1a, consistent with an increased proliferation rate. Intriguingly, the re-expression of Men1 in Men1-deficient OFMSCs restored Cdkn1a expression and abrogated cellular proliferation supporting the tumor-suppressive role of Men1 in OF. Although our work presents the first evidence of Men1 in OF development, it further provides the first genetic mouse model of OF that can be used to better understand the molecular pathogenesis of these benign tumors and to potentially develop novel treatment strategies.

Most of the reactive lesions in the oral cavity arise from gingiva. Fibroma, focal fibrous hyperplasia, pyogenic granuloma, and peripheral ossifying fibroma are the commonly encountered lesions of gingiva. Peripheral ossifying fibroma (POF) frequently arises from the peripheral tissues like gingiva. It is commonly found in females, mostly in the anterior of the molar region. POF is predicted to arise from the cells of periodontal ligament due to close proximity of gingiva to periodontal ligament. Its exact origin is unclear. The present article describes the case of recurrent peripheral ossifying fibroma located in the right lower premolar region in a 23-year-old female patient. Clinical, radiographic and histologic features as well as differential diagnosis, treatment and follow-up are discussed in this report. Early diagnosis along with surgical excision and curettage of surrounding tissue is important for the prevention of recurrences. Early conservative management of lesion reduces the risk of progression of lesion, and frequent follow-up visits are required to evaluate for recurrences.

Peripheral ossifying fibroma (POF) is a reactive lesion of oral tissues, associated with local factors such as trauma or presence of dental biofilm. POF treatment consists of curettage of the lesion combined with root scaling of adjacent teeth and/or removal of other sources of irritants. This study aimed to analyze the clinical and pathological features of POF and to investigate the immunoexpression of Osterix and STRO-1 proteins. Data such as age, gender, and size were obtained from 30 cases of POF. Microscopic features were assessed by conventional light microscopy using hematoxylin-eosin staining and immunohistochemical markers, and by polarized light microscopy using Picrosirius red staining. The age range was 11-70 years and 70% of the patients were female. Moreover, the size of POF varied from 0.2 to 5.0 cm; in 43.33% of the cases, the mineralized content consisted exclusively of bony trabeculae. The immunohistochemical analysis showed nuclear staining for Osterix in 63% and for STRO-1 in 20% of the cases. Mature collagen fibers were observed in mineralized tissue in 76.67% of the cases. The clinical and microscopic features observed were in agreement with those described in the literature. Osterix was overexpressed, while STRO-1 was poorly expressed. Osterix was expressed particularly in cells entrapped in and around mineralized tissue, indicating the presence of a stimulus that triggers the differentiation of these cells into osteoblasts or cementoblasts, i.e., cells that produce mineralized tissue. Based on our results, Osterix may play a role in the pathogenesis of POF.

Cemento-ossifying fibromas are rare fibro-osseous benign neoplasms that affect the jaws. They are included in the group of mesodermal odontogenic tumors and commonly present as a progressively growing lesion that might attain enormous size with resultant deformity, if left untreated. A confusion prevails on the terminology, which can only be confirmed by histopathologic evaluation. A case of cemento-ossifying fibroma involving the right mandible is described in a 30 year-old female patient. The clinical, radiographic, histologic features are presented and the various differential diagnosis are discussed.

Tumour-induced osteomalacia is a paraneoplastic syndrome wherein bone is affected by a hormone from a tumour that causes renal phosphate wasting and hypophosphataemia. Here, we present the case of a 31-year-old man who has been suffering from generalised bone pains and a spine deformity that led to loss of height. Pertinent findings are low serum phosphorus, low vitamin D and decreased bone mineral density. These findings led to a diagnosis of osteomalacia. However, the finding of an oral mass raised some questions as to what role it plays in the patient's disease. It was suspected that the oral mass (fibroma) was producing a hormone that led to renal phosphate wasting, hypophosphataemia and then osteomalacia. This hypothesis was proven after surgical removal of the mass led to normalisation of the metabolic derangements and eventually led to a resolution of the bone pains., Competing Interests: Conflicts of Interest: None declared., (2017 BMJ Publishing Group Ltd.)

Juvenile ossifying fibroma (JOF) is a rare fibro-osseous neoplasm that develops among the craniofacial bones at an early age; and in majority of patients, it is diagnosed in the first or second decade of life. We present a case in 41-year male patient having it in the left anterior mandibular region. Peripheral eosinophilic areas resembling psammomatoid bodies along with other features impelled the diagnosis of psammomatoid ossifying fibroma. However, the term juvenile seems to be losing impact with the patients showing such features in old age.

Aims: The objective of this study is to describe shared morphological features of peripheral giant cell granuloma (PGCG) and peripheral ossifying fibroma (POF) in detail and discuss the possible relationship between them., Materials and Methods: Ten intermediate cases with features resembling to both POF and PGCG were selected and type 3 and 1 collagen immunostainings were performed for evaluation of the connective tissue maturation. Immunohistochemical staining percentage (SP) for stromal cells in the slides of POF and PGCG counterparts of intermediate lesions was scored as 1 when the SP was above 10%, 2 when the SP was above 25%, 3 when the SP was above 50% and 4 when the SP was above 75%. Staining intensity (SI) of immunuhistochemical staining was graded and scored as 1 - mild, 2 - moderate, and 3 - severe. An immunoreactivity score was calculated by multiplying SP and SI., Results: All intermediate lesions comprised osteoclast type multinucleated giant cells and partly mineralized hard tissue component. Parts of intermediate lesions resembling POF showed higher type 1 collagen immunoreactivity compared to the PGCG counterparts of intermediate lesions (P < 0.05). PGCG counterparts showed higher type 3 collagen immunoreactivity compared to the POF counterparts of the intermediate lesions (P < 0.05)., Conclusion: POF may be a later stage lesion with morphologically more mature components. A possible transformation may be considered for these two lesions.

Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue neoplasm of uncertain differentiation, initially described by Enzinger and colleagues. Until now, nearly 300 such cases have been reported worldwide. The histogenesis of these tumors remains controversial. These tumors show characteristic imaging findings and exhibit a spectrum of histopathologic features, including classical and atypical subtypes. Local recurrences and, occasionally, distant metastases have also been reported. A complete tumor resection forms the preferred treatment modality for these tumors, along with follow-up, as these tumors have an uncertain malignant potential. Lately, certain "molecular signatures" underlying OFMTs have been described that can further aid in reaching an accurate diagnosis for these tumors and unraveling their pathogenesis. This article is a review of the clinical, radiologic, histopathologic, and molecular features of OFMTs.

A case of juvenile active ossifying fibroma affecting a 27 year-old man will be discussed. The characteristic radiologic and histologic features of the entity will be described.

Ossifying fibroma (OF) and fibrous dysplasia (FD) are benign, intraosseous, proliferative fibro-osseous lesions (PFOLs) characterized by replacement of normal bone by a fibrous matrix with various degrees of mineralization and ossification. Osteomas are benign tumors composed of mature, well-differentiated bone. Clinical, imaging, and histologic features of 15 initially diagnosed benign PFOLs and osteomas of the canine oral cavity were evaluated. Final diagnoses after reevaluation were as follows: OF (3 cases), FD (4 cases), low-grade osteosarcoma (LG-OSA) (3 cases), and osteoma (5 cases). Histology alone often did not result in a definitive diagnosis for PFOL. OF appeared as a well-circumscribed, radiopaque mass with some degree of bone lysis on imaging. Most lesions of FD showed soft tissue opacity with bone lysis and ill-defined margins. Low-grade OSA appeared as a lytic lesion with a mixed opacity and ill-defined margins. Osteomas were characterized by a mineralized, expansile, well-circumscribed lesion. Although histologic features of PFOLs were typically bland, the lesions diagnosed as LG-OSA had some features of malignancy (eg, bone invasion or a higher mitotic index). Treatment varied widely. Of the 10 dogs with benign PFOL or osteoma with known outcome (10/12), 9 showed either complete response (6/10) or stable disease (3/10) after treatment. Of the 2 dogs with LG-OSA with known outcome, 1 showed complete response after curative intent surgery, but 1 patient had recurrence after partial maxillectomy. Definitive diagnosis of mandibular/maxillary PFOL is challenging via histopathologic examination alone, and accurate diagnosis is best achieved through assimilation of clinical, imaging, and histopathologic features., (© The Author(s) 2015.)

Ossifying fibroma of the jaw is a benign fibroosseous tumour. The growth of it is slowly and it is well circumscribed. Occurrence of multiple ossifying fibromas (synchronous) is rare in the jaw, and only a few cases have been documented. The most of these cases were in only maxilla. The fewer cases were reported in both of maxilla and mandible. We report a case of bilateral synchronous ossifying fibromas involving the mandible of a 37 years old male. The importance of our case is that bilaterality and synchronous of the lesions. Our case is the first synchronous mandibler lesion in literature reported.

Benign fibro-osseous lesions of the craniofacial skeleton (BFOL) are a variant group of intraosseous disease processes that share similar microscopic features characterized by hypercellular fibroblastic stroma containing various combinations of bone or cementum-like tissue and other calcified structures [1-6]. Whereas some are diagnosable histologically, most require a combined assessment of clinical, microscopic and radiologic features. Some BFOL of the craniofacial complex are unique to that location whereas others are encountered in bones from other regions. Reactive, neoplastic, developmental and dysplastic pathologic processes are included under the rubric of BFOL and treatment varies from disease to disease. This review will discuss the clinical, microscopic and radiologic aspects of the more important types of BFOL of the craniofacial complex with updated information on underlying genetic and molecular pathogenic mechanisms of disease. Four main groups of BFOLs will be addressed.