Establishment of an Animal Model of Oral Squamous Cell Carcinoma Invading the Mandible.

OBJECTIVE: To establish an animal model of oral squamous cell carcinoma invading the mandible through multi-sample experiments that verified the stability, repeatability, tumorigenicity and mandible destruction rate of the model. METHODS: Oral squamous cell carcinoma cell suspension was injected into the outer side of the mandible through the anterior edge of the masseter muscle of naked mice to observe the tumourforming process. Then, the anatomical, histological and imaging examinations were carried out to determine whether the tumour had invaded the mandible. By comparing the tumour growth of multiple groups of various squamous cell carcinoma cells (CAL27, HN6 and HN30 cells), the changes in body weight and characteristics of tumour formation were compared, and the experience was summarised to further verify the stability, repeatability, tumour formation rate and arch damage rate of the model. RESULTS: The subsequent specimens of tumour-bearing nude mice were validated once the model had been established. In vitro, tumour tissue wrapped around the mandible's tumour-bearing side, and the local texture was tough with no resistance to acupuncture. Haematoxylin and eosin staining revealed that squamous cells were infiltrating the mandible in both the horizontal and sagittal planes. Microcomputed tomography results showed that the mandible on the tumour-bearing side displayed obvious erosion damage. Cell lines with various passage rates clearly had diverse tumour-bearing life cycles. CONCLUSION: This study successfully established an animal model of oral squamous cell carcinoma invasion of the mandible. The model has excellent biological stability, repeatability, tumorigenesis rate and mandible destruction rate.

Intraosseous myofibroma mimicking an odontogenic lesion: case report, literature review, and differential diagnosis.

BACKGROUND: Intraosseous myofibroma of the jaw is a rare neoplasm of mesenchymal origin with limited comprehensive understanding. It typically affects patients in the first two decades of life with a male predilection. CASE PRESENTATION: This study presents a rare case of myofibroma mimicking an odontogenic lesion in a 2-year-old boy. The patient presented with an incidental finding of a painless swelling of the right mandibular ramus of unknown etiology. Imaging analysis revealed a solid, expansile lesion adjacent to the germinal zone of the right mandibular first molar. Histopathologic analysis and immunohistochemistry after incisional biopsy suggested a possible central odontogenic fibroma, and the patient underwent total enucleation, leading to the final diagnosis of intraosseous myofibroma. Follow-up examinations showed no evidence of recurrence. CONCLUSIONS: This report contributes to the understanding of myofibroma in pediatric patients and underscores the critical role of meticulous histopathologic examination for effective surgical planning and optimal patient outcomes.

[Clincopathological analysis of 171 patients with osteochondroma and malignant transformation in maxillofacial bone].

PURPOSE: To investigate the clinical and pathological features of osteochondroma in maxillofacial region, and to summarize the clinicopathological features of rare osteochondroma malignant transformation in order to provide clinical guidance. METHODS: From January 2018 to September 2023, a total of 171 patients with osteochondroma were retrospectively collected in Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. Their preoperative CT and clinicopathological features were analyzed. RESULTS: Of the 171 patients with osteochondroma in maxillofacial bone, 66%（113/171） were females and 34% were male. Their age ranged from 11-76 with an average age was 44 years old. Of the 171 cases, 95.3%（163/171）in mandible condyle, 4%(7/171) in mandible processus coronoideus, and 0.5%（1/171） in zygomatic arch. The imaging findings showed that the thickness of cartilaginous cap was less than 1 cm in 98%（159/161） cases with condyle lesions. Only 2 cases(2/171, 1.1%) had malignant transformation. One was diagnosed with secondary chondrosarcoma, another developed low-grade osteosarcoma. CONCLUSIONS: Osteochondroma in maxillofacial region mostly occurs in females, and most commonly located in condylar process, with a malignant change rate of 1.1%, which is similar to that of other parts of the body. Imaging findings have important guiding significance for the diagnosis of osteochondroma malignant change.

Intelligent electromagnetic navigation system for robot-assisted intraoral osteotomy in mandibular tumor resection: a model experiment.

Background: Mandibular tumor surgery necessitates precise osteotomies based on tumor boundaries; however, conventional osteotomies often lack accuracy in predicting osteotomy positions and planes, potentially leading to excessive resection of normal bone tissues or residual tumors, thus compromising postoperative quality of life and clinical outcomes. Robotic-assisted surgery (RAS) augmented with artificial intelligence (AI) offers precise localization capabilities, aiding surgeons in achieving accurate osteotomy positioning. This study aimed to evaluate the feasibility and accuracy of a robotic magnetic navigation system for positioning and osteotomy in an intraoral surgical trial of a mandibular tumor model. Methods: Patient computed tomography (CT) imaging data of mandibular chin and body tumors were utilized to create 3D printed models, serving as study subjects for mandibular tumor resection. Ten pairs of models were printed for the experimental and control groups. The experimental group (EG) underwent osteotomy using a robot-assisted surgical navigation system, performing osteotomy under robotic navigation following alignment based on preoperative design. The control group (CG) underwent traditional surgery, estimating osteotomy position empirically according to preoperative design. Postoperative CT scans were conducted on both models, and actual postoperative results were compared to preoperative design. Osteotomy accuracy was evaluated by positional and angular errors between preoperatively designed and actual osteotomy planes. Results: For ten randomly selected spots on the left and right sides, respectively, the EG group had mean distance errors of 0.338 mm and 0.941 mm. These values were obtained from the EG group. In the EG group, on the left side, the mean angular errors were 14.741 degrees, while on the right side, they were 13.021 degrees. For the 10 randomly selected spots on the left and right sides, respectively, the CG had mean distance errors of 1.776 mm and 2.320 mm. This is in contrast to the results obtained by the EG. It was determined that the left side had a mean angle error of 16.841 degrees, while the right side had an error of 18.416 degrees in the CG group. The above results indicated significantly lower point errors of bilateral osteotomy planes in the experimental group compared to the control group. Conclusion: This study demonstrates the feasibility of electromagnetic navigation robot-assisted intraoral osteotomy for mandibular tumors and suggests that this approach can enhance the precision of clinical surgery.

Unicystic ameloblastoma: Clinico-radiological and histopathological correlation with management.

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

Ossifying fibroma: the peripheral variant.

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.

Introduction: Le fibrome ossifiant périphérique (FOP) est une excroissance gingivale solitaire dont on pense qu'elle provient des gencives, du périoste ou du ligament parodontal. Il s'agit d'une lésion progressive, bénigne et à croissance lente dont la taille est limitée. Description du cas: Cet article décrit le cas d'une variante périphérique du fibrome ossifiant survenue chez une femme de 26 ans, dans la région antérieure de sa mâchoire inférieure et se présentant comme une excroissance sur la gencive. Comme il était difficile d'établir un diagnostic clinique, une évaluation pathologique a été nécessaire. Après confirmation pathologique du diagnostic, la lésion a été excisée jusqu'au périoste lors d'une opération chirurgicale. On a jugé ce traitement nécessaire, puisque le taux de récidive du FOP est élevé (entre 8 % et 20 %). La patiente doit faire l'objet d'un suivi annuel pour rechercher toute récidive éventuelle.

Odontome and its pathological effect on surrounding teeth.

Odontoma is the most common odontogenic tumour derived from both epithelial and mesenchymal components of the tooth-forming apparatus. It is commonly diagnosed in the second and third decades of life when a radiograph is taken for some other purpose, as most cases are asymptomatic. This case involves a young boy, with the chief complaint of pain and swelling in the lower left back region. An intraoral examination revealed a carious and hypoplastic left permanent mandibular first molar. Although the molar was suspected as the source of his symptoms, radiographic imaging revealed multiple odontomas and missing second and third molar tooth buds. This case highlights the pathological effects of odontomas on surrounding teeth, including the malformation of the first molar and aplasia of the second and third molars. The sole management depends on the early diagnosis, histopathological examination to rule out malignancy and conservative surgical excision of these tissues.

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

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

Giant cell granuloma and neurofibroma in the mandible of a patient with neurofibromatosis type 1: a long-term follow-up case report with radiological and surgical aspects and a review of the literature.

BACKGROUND: Magnetic resonance imaging (MRI) of the brain is frequently performed on patients with neurofibromatosis type 1 (NF1), to detect and follow-up intracranial findings. In addition, NF1-related pathologies can appear in the jaws. This case study investigates if it is advantageous to assess the depicted parts of the jaws in the imaging of NF1 patients with intracranial findings, thereby detecting jaw pathologies in their initial stages. CASE PRESENTATION: We report on the 3-year management with clinical and radiological follow-ups of a central giant cell granuloma and a neurofibroma in the mandible of a patient with NF1 who underwent examinations with brain MRIs. A review of the mandible in the patient's MRIs disclosed lesions with clear differences in progression rates. CONCLUSION: NF1-related jaw pathologies may be detected in the early stages if the depicted parts of the jaws are included in the assessment of the imaging of NF1 patients with intracranial findings. This could impact the treatment of eventual pathologies before lesion progression and further damage to the vicinity.

Aggressive Late Recurrence of a Calcifying Epithelial Odontogenic Tumor: Surgical Refinements Based on New Technologies.

A calcifying epithelial odontogenic tumor is a rare, benign odontogenic neoplasm. Surgical treatment is the option, and late recurrence is very rare. Radiologically, the lesions are commonly present scattered calcifications. This case report details a 64-year-old female patient with a recurrence of a right mandibular calcifying epithelial odontogenic tumor 2 decades after successful initial surgical removal. A segmental mandibulectomy and immediate reconstruction were performed using a planned vascularized free fibula flap with virtual surgery, custom reconstruction plate, and intraoperative computed tomography. Modifications were made to the design of the reconstruction plate to improve the cervicofacial profile and subsequent rehabilitation with dental implants. Fully guided implant surgery with point-of-care manufacturing protocol was done to improve prosthetically driven implant planning. The case presented highlights the usefulness of new technologies for mandibular reconstruction with the free fibula flap and the concept of point-of-care with technical notes that increase precision and reduce morbidity in implant-supported rehabilitation.

Osteosarcoma associated with cemento-osseous dysplasia: co-incidence or two related entities?

BACKGROUND: Osteosarcoma of the jaws is a rare primary malignant tumor of bone. The clinical, radiological and histopathological features of a case associated with cemento-osseous dysplasia is presented. CASE REPORT: A 57-year-old mixed-race female presented with a large, progressive, swelling of the right mandible. Radiographic examination revealed two associated lesions. Partially defined irregular radiopacities were noted in the left mandible, extending from the premolar to the molar region. The lesion had a cotton-wool appearance and resembled a fibro-osseous lesion; i.e. cemento-osseous dysplasia. A second large, expansive and irregular, radiopaque lesion was noted on the right angle of the mandible, extending beyond the inferior cortex of the mandible. The internal structure was heterogeneous and resembled irregular bone formation. The classic "sunburst" appearance of radiating bony spicules can be seen in the posterior-anterior view and the CBCT 3D reconstruction, indicating the outgrowth of the tumor matrix. Histopathological exam confirmed a final diagnosis of osteosarcoma closely associated with cemento-osseous dysplasia. The patient underwent a fludeoxyglucose-18 (FDG) positron emission tomography (PET) scan which indicated metastasis in the left lung and increased uptake in the right mandible. Chemotherapy was initially administered with a plan to resect the tumor, however, the patient demised as a result of medical complications. CONCLUSION: The question in the literature remains whether these two entities are coincidentally found or arise from each other. Nevertheless, it is important for clinicians to closely monitor patients with cemento-osseous dysplasia and biopsy any suspicious lesions that may develop into osteosarcoma.

Odontogenic carcinoma with dentinoid: case report and literature review of a rare entity.

BACKGROUND: Odontogenic carcinoma with dentinoid (OCD) is a rare and controversial entity, which has not yet been included in the current World Health Organization classification of odontogenic lesions. Owing to the small number of reported cases, the clinicopathological characteristics, biological behavior, prognosis, and appropriate treatment strategies for OCD remain to be defined. Herein, we present an additional case of OCD with a focus on the differential diagnosis and review of the pertinent literature, in order to enable better recognition by oral clinicians and pathologists and further characterization of this entity. CASE PRESENTATION: This paper reports a case of OCD in the posterior mandible of a 22-year-old female. Radiography showed a well-defined unilocular radiolucency with radiopaque materials. The intraoperative frozen section pathology gave a non-committed diagnosis of odontogenic neoplasm with uncertain malignant potential. Then a partial mandibulectomy with free iliac crest bone graft and titanium implants was performed. Microscopically, the tumor consisted of sheets, islands, and cords of round to polygonal epithelial cells associated with an abundant dentinoid matrix. Immunohistochemically, the tumor cells were diffusely positive for CK19, p63, and ß-catenin (cytoplasmic and nuclear). No rearrangement of the EWSR1 gene was detected. The final diagnosis was OCD. There has been no evidence of recurrence or metastasis for 58 months after surgery. We also provide a literature review of OCD cases, including one case previously reported as ghost cell odontogenic carcinoma from our hospital. CONCLUSIONS: OCD is a locally aggressive low grade malignancy without apparent metastatic potential. Wide surgical excision with clear margins and long-term period follow-up to identify any possible recurrence or metastases are recommended. Histopathological examination is essential to conclude the diagnosis. Special care must be taken to distinguish OCD from ghost cell odontogenic carcinoma and clear cell odontogenic carcinoma, as misdiagnosis might lead to unnecessary overtreatment. Study of additional cases is required to further characterize the clinicopathological features and clarify the nosologic status and biological behavior of this tumor.

Central giant cell granuloma in the posterior region of mandible mimicking a fibro-osseous lesion and hemangioma: a case report.

BACKGROUND: A central giant cell granuloma (CGCG) is a benign, proliferative, intraosseous, and non-odontogenic lesion occurring primarily in children and young adults. On the histological level, it is characterized by numerous multinucleated giant cells scattered randomly throughout a sea of spindle-shaped mesenchymal stromal cells which are dispersed throughout the fibrovascular connective tissue stroma containing areas of haemorrhage. When it comes to radiographic features, CGCG can have an array of variations, ranging from well-defined expansile lesions to ill-defined and destructive lesions, with or without expansion. CASE PRESENTATION: This case report reviews an 11-year-old Caucasian patient with a chief complaint of slow-growing swelling involving the right posterior mandibular region. The cone beam computed tomography (CBCT) revealed an ill-defined mixed lesion mimicking both fibro-osseous lesion and hemangioma. However, microscopic examination revealed multinucleated giant cells in a fibrous stroma suggestive of central giant cell granuloma. CONCLUSION: Our intent in reporting this case is to highlight the importance of thorough clinical, radiographical and histopathological examination for accurate diagnosis and therapeutic interventions as well as to emphasize the importance of taking different possibilities into consideration when examining bony swellings in the head and neck region.

Mandibular rhabdomyosarcoma with TFCP2 rearrangement and osteogenic differentiation: a case misdiagnosed as fibrous dysplasia or low-grade central osteosarcoma.

Rhabdomyosarcoma with TFCP2-related fusions (TFCP2-RMS) is a rare entity that commonly affects young adults with a predilection for skeletal involvement. We herein report a 40-year-old female patient with TFCP2-RMS who was misdiagnosed as fibrous dysplasia or low-grade central osteosarcoma of the mandible by referring institutions. Histologically, the tumor showed dominant spindle cells and focal epithelioid cells with marked immature woven bone formation. Immunophenotypically, in addition to the characteristic expression of myogenic markers, ALK, and cytokeratins, tumor cells also unusually expressed osteogenic markers, such as MDM2 and SATB2. Through fluorescence in situ hybridization, the tumor cells showed EWSR1::TFCP2 gene fusion and no MDM2 gene amplification. This is a rare case of TFCP2-RMS, which was misdiagnosed as low-grade central osteosarcoma due to its presenting immunophenotype of MDM2 and SATB2, as well as extensive osteoid matrix formation.

The 'D-M-C' strategy for conventional ameloblastoma of the mandible: a retrospective study.

The purpose of this multicentre study was to evaluate the efficacy of the 'dredging-marsupialization-curettage' (D-M-C) strategy in the treatment of conventional intraosseous ameloblastoma of the mandible. A total of 31 patients from three institutions, who had a pathological diagnosis of conventional ameloblastoma of the mandible, were treated with the D-M-C strategy. The surgical protocol comprised a dredging and marsupialization (D-M) step, with additional D-M steps as required. The patients then underwent curettage (C) once an obvious effect of the D-M step had been achieved during follow-up. Eight patients were followed up for ≥36 months but <60 months, while 23 were followed up for ≥60 months. Nineteen of the 23 patients followed up for ≥60 months were disease-free at the last follow-up, with no evidence of recurrence. The D-M step is effective for reducing the tumour size and preserving vital structures. The D-M-C surgical strategy may be a feasible treatment option for conventional ameloblastoma of the mandible.

Aggressive presentation of ameloblastic fibro-odontoma: a clinical-pathological enigma.

Ameloblastic fibro-odontoma (AFO) is a rare, gnathic, benign, mixed odontogenic tumor that commonly presents in the first or second decade of life as a unilocular and rarely multilocular radiolucency with variable amounts of calcified material. Tumor progression is typically indolent, and generally accepted treatment is surgical enucleation and curettage. This case report describes an atypical presentation in a 14-year-old male with a multilocular, aggressive AFO requiring hemimandibulectomy with immediate osseous and dental "Jaw-in-a-Day" reconstruction. This report highlights the debate regarding whether AFO is a true neoplasm or an early-stage hamartoma in the continuum of complex odontoma formation. Regardless of the pathogenesis, maxillofacial surgeons and pathologists should be cognizant of the potential for AFO to develop locally aggressive behavior with considerable morbidity.

Sclerosing epithelioid fibrosarcoma of the jaw: a case report and literature review.

INTRODUCTION: Sclerosing epithelioid fibrosarcoma (SEF) is an extremely rare form of bone and soft tissue sarcoma. It occurs mainly in the deep soft tissue of the lower extremities, with few cases reported in the head and neck region. Tumors involving the oral and maxillofacial region (OMFR) and intraosseous examples are rare. CASE PRESENTATION: We present a 52-year-old male with a radiolucent lesion at the apex of the left mandibular second molar tooth with the clinical impression of a periapical granuloma. The patient has a history of SEF of the skull, which was treated by chemotherapy and radiation. Histopathologic examination revealed islands of highly cellular, basophilic bone and osteoid surrounded by loose fibrous stroma, which contains large lobules and islands of round to oval cells with distinct cell borders and faintly granular eosinophilic cytoplasm. Tumor cells were strongly positive for MUC4 and INI-1. Based on these findings, a diagnosis of high-grade malignancy consistent with SEF was made, and correlation with the primary lesion was recommended. CONCLUSION: SEF is a rare tumor seen in OMFR, and therefore, it should be included in the differential diagnosis of any high-grade malignancy. Immunohistochemical stain for MUC-4 evaluation is important for the diagnosis of SEF.