Incidence and overall survival of malignant ameloblastoma

Clear and Spindle Cell Dedifferentiation in Ameloblastic Carcinoma: A Case Report on a Uncommon Phenomenon

Ameloblastic carcinoma is a rare malignant neoplasm with characteristic histopathological features that are directed towards an aggressive surgical approach than benign odontogenic lesions. It affects people of all ages, mostly in the posterior mandible, without a preference for race or gender. De novo cancer is one of its primary types, while the second type is defined as a malignant change from an antecedent case of benign ameloblastoma. The rapid progression of molecular biology led to the revelation that ameloblastoma contains a BRAF-V600E genetic mutation over 60%. Besides conventional ameloblastic carcinomas, rare histologic variants have also been described in the literature, including clear and spindle cells. These variants pose diagnostic challenges as to whether it is a dedifferentiation or a distinct entity. The dearth of data lends credence to the notion that these histologic variations are related to high-grade neoplasms and more aggressive outcomes. As a result, the current report intends to analyze a series of patients diagnosed with conventional ameloblastic carcinoma of the head and neck region with spindle and clear cell types along with a brief assessment of the literature.

Rare solitary pituitary metastasis of maxillary ameloblastic carcinoma: illustrative case

BACKGROUND

Ameloblastic carcinoma (AC) is a rare odontogenic carcinoma with histological features resembling ameloblastoma. Metastasis to distant organs and direct expansion into the skull base structures are associated with a poor clinical outcome. This rare case of AC metastasis to the pituitary gland presented without local recurrence at the primary focus of the maxilla.

OBSERVATIONS

A 47-year-old man had a 2-year history of AC in the right maxilla. Computed tomography for his regular checkup incidentally demonstrated pituitary tumor, rapidly growing over 2 months. He presented with the recent onset of panhypopituitarism and visual field defect. Magnetic resonance imaging showed a large, irregularly shaped intrasellar and suprasellar lesion with chiasmal compression. Endoscopic endonasal transsphenoidal surgery was performed for decompression of the optic apparatus to avoid intracranial spread. Histopathology confirmed metastatic AC, and a genetic panel test confirmed BRAF V600E mutation. Stereotactic radiotherapy (SRT) with the CyberKnife system was administered to the residual tumor. Remarkable tumor shrinkage was obtained, and panhypopituitarism was resolved 12 months later.

LESSONS

A multidisciplinary treatment strategy including maximal safe resection to avoid dissemination in combination with SRT may be crucial for local control with the preservation of pituitary and visual functions in patients with solitary pituitary metastatic AC.

Diagnosis, Treatment, and Total Rehabilitation of a Secondary Type Ameloblastic Carcinoma

Ameloblastic carcinoma (AC) is an uncommon malignant odontogenic tumor, with about 200 cases published in the literature. Here, we report a case of AC occurring in the maxilla - at the same anatomical location of an ameloblastoma 8 years earlier. A 23-year-old woman with maxillary swelling of 6-month duration was referred to our service. Extraoral examination revealed a swelling over the right side of the face, lifting her lip and nose. Intraorally, a firm, reddish, nodular swelling involving the right maxilla was observed. Computed tomography showed a hypodense image invading the right maxilla, maxillary sinus, and nasal fossa. An incisional biopsy was performed, followed by histopathologic examination and an immunohistochemical panel, which led to the diagnosis of AC. The lesion was treated with partial maxillectomy followed by immediate rehabilitation. Neither local recurrence of the tumor nor distant metastasis was observed during a 4-year follow-up. AC is a highly malignant lesion which requires aggressive therapy. Its diagnosis should be based on combined clinical, imaging, and pathological manifestations in order to improve diagnostic accuracy.

Precision medicine: Sustained response to erdafitinib in FGFR2 ‐mutant, multiply recurrent ameloblastoma

Background

Ameloblastoma imposes significant morbidity and high‐recurrence rates following surgery and radiation therapy. Although 89% of cases harbor oncogenic mutations, the role of targeted therapy is undefined.

Case

We describe a case of a 40‐year‐old male with multiply recurrent, locally invasive ameloblastoma of the posterior maxillary ridge. The tumor was unresectable for negative margins due to extensive intracranial disease, and the patient suffered severe symptoms including pain. Immune and genomic profiling were obtained to guide systemic treatment, showing a PD‐L1 score of 2% and FGFR2^V395D and SMO^W535L mutations. The patient progressed rapidly on anti‐PD1 immunotherapy. He was treated with the FGFR inhibitor, erdafitinib, with excellent partial response including resolution of intracranial disease and cancer‐related pain, ongoing 2 years after drug initiation.

Conclusion

Targeting the FGFR2 mutation resulted in sustained response and improved quality of life. Genomic profiling with targeted therapy for ameloblastoma appears promising, especially when surgery is technically infeasible.

Precision drugging of the MAPK pathway in head and neck cancer

The mitogen-activating protein kinase (MAPK) pathway is central for cell proliferation, differentiation, and senescence. In human, germline defects of the pathway contribute to developmental and congenital head and neck disorders. Nearly 1/5 of head and neck squamous cell carcinoma (HNSCC) harbors MAPK pathway mutations, which are largely activating mutations. Yet, previous approaches targeting the MAPK pathway in HNSCC were futile. Most recent clinical evidences reveal remarkable, or even exceptional pharmacologic vulnerabilities of MAPK1-mutated, HRAS-mutated, KRAS-germline altered, as well as BRAF-mutated HNSCC patients with various targeted therapies, uncovering diverse opportunities for precision drugging this pathway at multiple “genetically condemned” nodes. Further, recent patient tumor omics unveil novel effects of MAPK aberrations on direct induction of CD8⁺ T cell recruitment into the HNSCC microenvironment, providing evidences for future investigation of precision immunotherapy for this large subset of patients. MAPK pathway-mutated HNSCC should warrant precision therapy assessments in vigorous manners.

Transformation of ameloblastoma to ameloblastic carcinoma in a 10-year-old child

Ameloblastic carcinoma (AC) is a rare odontogenic malignant epithelial neoplasm of maxillofacial skeleton with a distinct predisposition of the mandible. It can occur in a wide range of age groups, with a sex predilection in males. It can arise either as a de novo lesion or from preexisting ameloblastoma. AC has a high propensity for local recurrence as well as distant metastasis (chiefly lungs), thus requiring an aggressive surgical approach and a strict surveillance. Owing to the rarity of publications describing AC, little is known about this entity in pediatric patients. We report a case of transformation of ameloblastoma into AC in a 10-year-old child.

Roles of mesenchymal stromal cells in the head and neck cancer microenvironment

Head and neck cancer (HNC), a common malignancy worldwide, is associated with high morbidity and mortality rates. Squamous cell carcinoma is the most common HNC type, followed by salivary gland carcinomas, head and neck sarcomas, and lymphomas. The microenvironment of HNCs comprises various cells that regulate tumor development. Recent studies have reported that the tumor microenvironment, which modulates cancer progression, regulates cancer treatment response. However, the presence of different types of stromal cells in cancers is a major challenge to elucidate the role of individual cells in tumor progression. The role of mesenchymal stromal cells (MSCs), which are a component of the tumor microenvironment, in HNC is unclear. The major impediment for characterizing the role of MSCs in cancer progression is the lack of MSC-specific markers and their phenotypic similarity with stromal cells. This review aimed to summarize the latest findings on the role of MSCs in the progression of HNC to improve our understanding of HNC pathophysiology.

Malignant Odontogenic Tumours: A Systematic Review of Cases Reported in Literature

Background: Malignant odontogenic tumours (MOTs) arise either de novo from the tooth forming tissues, their developmental residues or from existing odontogenic epithelial or mesenchymal neoplasms in the jaws. Their management requires extensive surgery due to their infiltrative nature and risk of metastasis. There is a need to understand the clinical and pathological features of MOTs to inform both treatment algorithms and prognostication. This is an area of diagnostic pathology which presents substantial difficulties in diagnosis, compounded by inconsistent use of terminology. Thus, this systematic review aimed to describe the clinical and pathological features of MOTs with a view to consolidating the literature and defining problematic areas in diagnosis and classification. Methods: An electronic database search was conducted in Web of Science, PubMed/Medline, and Embase. Additionally, the grey literature and reference lists of selected papers searched for completeness. Nine hundred and sixty articles were initially identified. Following removal of duplicates and application of inclusion/exclusion criteria, 312 articles were included for qualitative analysis. Results: The 312 articles encompassed a total of 507 patients with most lesions located within the mandible (74.3%). The most common first histological diagnosis was ameloblastic carcinoma (25.7% of all diagnoses), but there is considerable variation in how and when various diagnostic terms are used, and several misdiagnoses were reported. An initial benign diagnosis was made in 24.7% of patients, followed by a later malignant diagnosis and in this sub-group, the most common benign first diagnosis was ameloblastoma (42.4%). Cervical lymph nodes were the most common site of metastasis (9.3% of patients). With respect to distant metastasis (DM), the lungs were the most common organ affected (11.2% of DM patients) with metastasising ameloblastoma the most commonly reported tumour which metastasised to the lungs. Overall, 26.8% of patients developed recurrence. Conclusion: Overall, the quality of the literature on MOTs is poor. This review of the literature has highlighted variations in diagnostic terms and criteria which has resulted in areas of confusion with potential for misdiagnosis. This consolidation of primary data has identified key areas for targeted research including further discussion on the malignant potential of ameloblastoma.

Treatment efficacy and prognosis of pulmonary metastasizing ameloblastoma: a systematic review

The aim of this review was to integrate the current literature into a comprehensive evaluation of pulmonary metastasizing ameloblastoma (MA). Related articles, published since January 2000, were reviewed. The PubMed, Embase, Cochrane Database of Systematic Reviews, and Web of Science databases were searched based on the PRISMA guidelines. Twenty-four studies, including 28 case reports, met the eligibility criteria. The mean ± standard deviation disease-free interval after primary treatment was 12.1 ± 9.3 years. Adjuvant therapy (surgery and chemoradiotherapy) is considered appropriate for pulmonary MA patients presenting with rapid progression or apparent pulmonary symptoms. The proportion of patients undergoing simple follow-up (observation) has increased rapidly in the past 10 years. Meanwhile, among the three treatment groups (observation, surgery, and adjuvant therapy), no significant difference was found in the efficacy (P = 0.081) or progression-free survival (P = 0.263). The 5-year and 10-year overall survival rates were 72.4% and 52.8%, respectively. This study provides insights that could help surgeons with the management of patients presenting with pulmonary MA.

Rare Ameloblastic Carcinoma Metastasis to the Cervical Spine: A Case Report

BACKGROUND AND IMPORTANCE

Ameloblastic carcinoma (AC) is a malignant neoplasm of epithelial origin that typically arises from the mandible or maxilla. It represents approximately 2% of all odontogenic tumors. Gross total resection is the surgical goal given AC's aggressiveness and propensity for recurrence. We present the first reported AC metastasis to the cervical spine.

CLINICAL PRESENTATION

A 61-yr-old African American female with a history of AC of bilateral mandibles and lung metastases presented with neck pain and right arm weakness progressive over several months. Cervical spine imaging demonstrated a cervical 3 pathological fracture with severe anterior vertebral body compression and resultant cervical 2-3 kyphotic deformity and bony retropulsion causing severe cord compression. The patient underwent a cervical 3 corpectomy and cervical 2-4 anterior fixation followed by a cervical 3 laminectomy and cervical 2-5 dorsal internal fixation and fusion. Postoperatively, the patient's neurological exam remained stable and imaging showed improved spinal alignment and appropriate anterior and posterior instrumentation. Unfortunately, the patient thereafter suffered a decline in performance status and progression of lung metastatic disease. Her oncology team is considering chemotherapy and stereotactic radiosurgery, but her prognosis remains grim.

CONCLUSION

AC is a rare and aggressive pathology with a poor prognosis despite multimodal therapy. We present the first case of AC metastatic spread to the spine. We aim to bring this pathology to the attention of our worldwide neurosurgical colleagues and share our surgical approach and multidisciplinary management to assist those who may encounter this pathology in the future.

Whole exome sequencing and system biology analysis support the "two-hit" mechanism in the onset of Ameloblastoma

BACKGROUND

Ameloblastoma is the most frequent odontogenic tumor. Various evidence has highlighted the role of somatic mutations, including recurrent mutation BRAF V600E, in the tumorigenesis of Ameloblastoma, but the intact genetic pathology remains unknown.

MATERIAL AND METHODS

We sequenced the whole exome of both tumor tissue and healthy bone tissue from four mandibular ameloblastoma patients. The identified somatic mutations were integrated into Weighted Gene Co-expression Network Analysis on publicly available expression data of odontoblast, ameloblast, and Ameloblastoma.

RESULTS

We identified a total of 70 rare and severe somatic mutations. We found BRAF V600E on all four patients, supporting previous discovery. HSAP4 was also hit by two missense mutations on two different patients. By applying Weighted Gene Co-expression Network Analysis on expression data of odontoblast, ameloblast, and Ameloblastoma, we found a proliferation-associated gene module that was significantly disrupted in tumor tissues. Each patient carried at least two rare, severe somatic mutations affecting genes within this module, including HSPA4, GNAS, CLTC, NES, and KMT2D. All these mutations had a ratio of variant-support reads lower than BRAF V600E, indicating that they occurred later than BRAF V600E.

CONCLUSIONS

We suggest that a severe somatic mutation on the gene network of cell proliferation other than BRAF V600E, namely second hit, may contribute to the tumorigenesis of Ameloblastoma.

Malignant Ameloblastoma with Hepatic Metastasis in a 38-Year-Old Haitian Woman

BACKGROUND Primary malignant ameloblastoma is a very rare tumor of the dental lamina epithelium. Similar to the benign ameloblastoma, the mass is without significant histological atypia, but the malignant type may present with metastases, most commonly to the lungs. The average age of diagnosis is 34 years, and the malignancy affects men and women equally. The tumors often present with an insidious growth and have a median survival from time of diagnosis of 17.6 years. Due to the rarity of this lesion, a standard of care has not yet been established. CASE REPORT A 38-year-old Haitian woman, who initially presented with a large primary malignant ameloblastoma of the angle of the mandible, experienced a recurrence in the floor of the mouth 30 months after surgical resection. In 2018, 2 years after the removal of the recurrent tumor, the patient presented with ascites, right-sided abdominal pain, weight loss, and a palpable liver mass. Laparoscopic exploration demonstrated a complex lateral right liver lobe cyst, suspicious for parasitic infection. Cytological analysis showed positive staining for cytokeratin 5/6, P63, and CD56, indicative of metastatic ameloblastoma of the liver. Consistent cell morphology from the primary tumor and liver cyst was also noted. Following drainage of the cyst, the patient returned to Haiti, where she died in 2020. In Haiti, she lacked appropriate local medical care, leading to the severe progression of her initial primary ameloblastoma and disease recurrence. CONCLUSIONS Malignant ameloblastoma accounts for less than 2% of all odontogenic tumors, as the benign variant is much more common. Distant metastases of these lesions are rare; to date, few cases have presented with hepatic metastases.

Metastatic mandibular ameloblastoma of the lung ten years after primary resection: A rare case report

Ameloblastoma is a rare odontogenic neoplasm of the jaw. It usually behaves as a benign, slow growing tumour of the oral cavity with a high recurrence rate, especially when it is inadequately resected. A small proportion of ameloblastomas metastasize to distant organs, with lungs representing the most common site of metastatic spread. In this report, we present the case of a middle-aged man with two pulmonary nodules and a history of mandibular ameloblastoma excised 10 years prior to this radiological finding. Following resection and histopathological analysis of the lung lesion, a diagnosis of metastatic ameloblastoma was confirmed. No local recurrence of the primary tumour was identified. At 1-year follow-up, the patient had no evidence of local or metastatic disease.

Correlation of BRAF mutational status with clinical characteristics and survival outcomes of patients with ameloblastoma: the experience of 11 Italian centres

AIMS

Ameloblastoma is a rare odontogenic tumour with an aggressive local behaviour. Mutations in the mitogen-activated protein kinase pathway, namely BRAF V600E mutations, are a common finding. To date, there is no clear correlation between BRAF V600 mutation and clinical outcome.

METHODS

We retrospectively reviewed the medical records of patients who underwent surgery for ameloblastoma between May 1998 and June 2018, at 11 participating Italian centres. BRAF mutational status was evaluated by quantitative PCR/pyrosequencing. The primary end points were to determine BRAF mutational status in primitive and recurrent ameloblastoma, and to assess the relapse-free interval (RFI); the secondary end point was to investigate the correlation of BRAF mutational status with the clinical features of the tumour and survival outcomes.

RESULTS

Overall, 74 patients were included: 33 (44.5%) were BRAF wild type and 41 (55.4%) BRAF V600 mutated. BRAF V600 mutated ameloblastomas occurred more frequently in younger patients (p=0.0031), were located at the mandible (p=0.0009) and presented with unicystic variant. After a median follow-up of 60 months, 21 (28.3%) patients relapsed (30.3% and 26.8% in the BRAF wild type and BRAF mutated group, respectively). At univariable Cox models, none of the investigated variables, including microscopic margin involvement, was associated with RFI.

CONCLUSIONS

Local recurrence occurs in 30% of patients with ameloblastoma. BRAFV600 mutation is associated with younger age, mandibular localisation and with unicystic ameloblastoma. Neither BRAF mutation nor microscopically positive surgical margins were associated with RFI. Further studies are needed to elucidate outcomes of this rare disease according to clinical, histopathological and comprehensive molecular features.

Metastasizing Ameloblastoma: A 10 Year Clinicopathological Review with an Insight Into Pathogenesis

Ameloblastoma, a benign but locally aggressive odontogenic tumor, often demonstrates metastasis despite benign histological features and this variant is termed as metastasizing ameloblastoma (METAM). It was classified under the malignant category in the 2005 WHO but has been re-classified under benign epithelial odontogenic tumors in the latest 2017 WHO classification. The present review aimed at gathering the available data on METAM to update the current cognizance about the pathology. Comprehensive search of the databases (viz., PubMed, Medline, SCOPUS, Web of Science, EMBASE and Google Scholar) was done for published articles on METAM following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 42 cases were extracted. The mean age of occurrence was 42.71 ± 15.87 years. A slight male predilection was noted. Mandibular cases showed more metastasis than maxillary cases. Follicular ameloblastoma was most frequently encountered at secondary site followed by plexiform type. Lungs were the most commonly affected secondary sites. METAM is a rare odontogenic tumor and the diagnosis is usually made in retrospect. Inadequate treatment may result in multiple recurrences and metastasis in rare instances. Metastasis in ameloblastoma appears to be multi-factorial in nature and needs further investigation in untapped territory like exploration of quantum effects at cellular and molecular levels.

Patterns of Care and Survival Outcomes for Odontogenic Cancers

OBJECTIVES

Our understanding of odontogenic cancers is limited primarily to case studies given the rarity of these head and neck neoplasms. Using the National Cancer Database, we report the treatment patterns and survival outcomes for one of the largest cohorts of patients with odontogenic cancers.

METHODS

Patients with odontogenic tumors who did not have metastatic disease and received at least part of their care at the reporting facility were included. Patient and treatment variables were assessed using logistic regression. Survival was assessed using Cox proportional hazard models.

RESULTS

We identified 437 patients with odontogenic cancers, the majority of which had malignant ameloblastoma (n = 203) or odontogenic carcinoma (n = 217). Median follow-up was 44.8 months. On multivariate analysis, improved survival was associated with age <57 years (Hazard ratios [HR] 0.44, P = .012), lower comorbidity scores (HR 0.40, P = .008), surgical resection (HR 0.08, P < .001) and absence of lymph node metastasis (HR 0.23, P < .001). The 5-year overall survival was 87.1% for debulking surgery, 88.6% for radical resection and 26.6% for no surgical resection (P < .001). Lymph node metastases were associated with tumor size ≥5 cm (P = .006), malignant odontogenic histology (P = .025), and moderate/poor differentiation (P < .001).

CONCLUSION

In this large series of odontogenic cancers, any type of surgical resection was associated with improved survival. Lymph node metastases, although infrequent, were associated with significantly worse survival.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 131:E1496-E1502, 2021.

Pulmonary resection for multiple lung metastasis from ameloblastoma: a rare case report and literature review

INTRODUCTION

Ameloblastoma is a benign odontogenic epithelial neoplasm. Lung metastasis of ameloblastoma is extremely rare, and its biological behavior is still largely unknown. There is no consensus regarding the best method to treat metastasizing ameloblastoma.

CASE PRESENTATION

This report documents a 37-year-old female patient with multiple incidental bilateral pulmonary nodules on computed tomography (CT) and a medical history of ameloblastoma of the left mandible. On admission, her physical examinations and laboratory examinations were unremarkable. The patient underwent partial lobectomy of the middle right and lower right lung nodules via video-assisted thoracoscopic surgery, and the pathological diagnosis was confirmed as 'metastasizing ameloblastoma.' No adjuvant therapy was administered, and no evidence of progression was observed at the 12-month follow-up.

CONCLUSION

This is a rare case with multiple lung metastasis from ameloblastoma who was successfully treated with multiple pulmonary resections. The present study indicated that surgery may be considered an appropriate choice for lung metastasis of ameloblastoma.

World Health Organization Classification of Odontogenic Tumors and Imaging Approach of Jaw Lesions

Tumors of the jaws represent a heterogeneous group of lesions that are classified histologically in the World Health Organization Classification of Odontogenic Tumors (2017). This article provides an update of the current nomenclature. The main role of imaging is to describe the precise location and extent of these lesions. Although characterization of imaging is often difficult due to overlapping characteristics, imaging is helpful to define which lesions should be referred for histologic examination and subsequent treatment planning. Location and density are the cardinal criteria for potential characterization on imaging. Radiologically, lesions may be radiolucent, radiopaque, or of mixed density. Additional criteria include lesion demarcation, morphology, cortical breakthrough, periosteal reaction, and adjacent soft tissue changes. Final lesion characterization is only definitive after interdisciplinary discussion and radiopathologic correlation. Correct diagnosis is obtained by a combination of the patient's age, lesion location, and clinical and radiologic presentation. It is important that all physicians use a uniform nomenclature.

Ameloblastoma: A succinct review of the classification, genetic understanding and novel molecular targeted therapies

Ameloblastomas are benign but locally invasive neoplasms which may grow to massive proportions and cause significant morbidity. Although some types of ameloblastoma can be treated predictably with aggressive surgical treatment, recurrent ameloblastoma and metastasising ameloblastoma are still difficult to treat. Recent studies have identified recurrent somatic and activating mutations in the mitogen-activated protein kinase (MAPK) and sonic hedgehog (SHH) signalling pathways in ameloblastoma. This development provided a possibility that molecular targeted therapies can be used as neoadjuvant treatment. In this review, we provide a summary of the latest WHO classification of ameloblastoma, the current understanding of genetic mutations and novel molecular targeted therapies arising from the recent developments.

Discovery of novel molecular characteristics and cellular biological properties in ameloblastoma

Ameloblastoma is a rare odontogenic benign tumor accounting for less than 1% of head and neck tumors. Advanced next generation sequencing (NGS) analyses identified high frequency of BRAF V600E and SMO L412F mutations in ameloblastoma. Despite the existence of whole genomic sequence information from patients with ameloblastoma, entire molecular signature of and the characteristics of ameloblastoma cells are still obscure. In this study, we sought to uncover the molecular basis of ameloblastoma and to determine the cellular phenotype of ameloblastoma cells with BRAF mutations. Our comparative cDNA microarray analysis and gene set enrichment analysis (GSEA) showed that ameloblastoma exhibited a distinct gene expression pattern from the normal tissues: KRAS-responsive gene set is significantly activated in ameloblastoma. Importantly, insulin like growth factor 2 (IGF2), a member of KRAS-responsive genes, enhances the proliferation of an ameloblastoma cell line AMU-AM1 with BRAF mutation. In addition, Toll-like receptor 2 (TLR2) knockdown readily inactivated KRAS-responsive gene sets as well as increases caspase activities, suggesting that TLR2 signaling may mediate cell survival signaling in ameloblastoma cells. Collectively, the findings may help to further clarify the pathophysiology of ameloblastoma and lead to the development of precision medicine for patients with ameloblastoma.

Differential Diagnosis of Periapical Radiopacities and Radiolucencies

Periapical pathoses represent changes noted at the apices of teeth within the alveolar process that are suspected on examination, visualized via imaging, and confirmed via histopathology. They can be bone forming or destructive. There are pathologic entities that show both types of changes at the apical regions. These lesions must be identified if they are odontogenic in origin because treatment modalities differ. This article discusses identification of radiopaque and radiolucent lesions noted on radiographs. The common opacities and lucencies are described. When required, advanced imaging is used to depict changes within the bone near the periapical regions of mandibular and maxillary teeth.

The Significance of Relative Claudin Expression in Odontogenic Tumors

Claudins are integral to the structure and function of tight junctions. Altered claudin expression has been shown to affect disease behavior and patient prognosis in various neoplasms. The objectives of this study were to analyze the claudin-1, -4 and -7 expression in odontogenic tumors and characterize their expression pattern in distinct tumor cell types in relation to the recurrence potential. Sixty-nine cases of odontogenic tumors, including 43 ameloblastomas (AM), 17 adenomatoid odontogenic tumors (AOT), 6 ameloblastic fibromas (AF) and 3 ameloblastic carcinomas (AC) were investigated for claudin-1, -4 and -7 expression immunohistochemically. The staining was analyzed semi-quantitatively and categorized into 4 levels, based on the percentage of positively stained neoplastic epithelial cells. Claudin-1 was expressed in all AOT and AF cases, whereas most AC (66.7%) showed no expression. The claudin-1 staining was moderate-to-intense in the odontogenic epithelium of AF. In contrast, its staining of ameloblast-like cells and stellate reticulum-like cells in AM was weak. Claudin-7 expression was noted in all tumor types studied, while the expression of claudin-4 was limited and mainly localized in the squamous differentiated cells of AM and AC. AM showed significantly higher claudin-4, but lower claudin-7 expression than AOT. In addition, AC showed diminished claudin-1 immunoreactivity, compared to AOT. Low claudin-1 expression in AM was significantly associated with the increased clinical recurrence. The loss of claudin-1 may underlie the locally invasive nature of AM.

MAID chemotherapy regimen as a treatment strategy for metastatic malignant ameloblastoma: A case report

RATIONALE

Ameloblastoma is generally characterized as a benign tumor originating in odontogenic epithelium. However, few cases of metastatic malignant ameloblastoma have also been reported. Due to the low incidence of malignant ameloblastoma, there is no established treatment regimen. To explore effective treatment for malignant ameloblastoma, we reported this case study.

PATIENTS CONCERNS

This report described a case of a 28-year-old malignant ameloblastoma female patient with multiple metastasis (brain and lung).

DIAGNOSES

The patient presented ameloblastoma of the left mandible in 2012. Three years later, local recurrence and brain metastasis was observed during a follow-up examination. Five years later, malignant ameloblastoma was detected by imaging and immunohistochemistry in the bilateral multiple pulmonary nodules and mediastinal lymph nodes.

INTERVENTIONS

The patient was initially treated with tumor resection. Three years later after local recurrence and brain metastasis, she was accepted the extensive mandibulectomy supplemented with brain stereotactic body radiotherapy (SBRT). When diagnosed with pulmonary metastasis, the patient received combined chemotherapy regimen of MAID (mesna, adriamycin, ifosfamide and dacarbazine) for 6 cycles.

OUTCOMES

The efficacy evaluation was partial remission (PR) after the 6 cycles of MAID. The last patient follow-up was July 24th 2018, and no evidence of progression was observed. The progression-free survival (PFS) of the patient was more than 9 months.

LESSONS

Surgical resection is the optimal treatment for locally recurrent ameloblastoma. SBRT may be an effective treatment for unresectable oligometastasis of malignant ameloblastoma. Finally, combined chemotherapy of MAID showed encouraging effects in the management of metastatic malignant ameloblastoma.

Ameloblastic Carcinoma In Situ: Review of Literature and a Case Presentation in a Pediatric Patient

Ameloblastic carcinomas are rare malignant lesions with 3 mandibular pediatric cases reported in the literature. We present a case of ameloblastic carcinoma in situ in a 15-year-old male with a right mandibular cystic lesion on computed tomography. The incisional biopsy revealed plexiform ameloblastoma. Due to the infiltrating and aggressive nature of the tumor, the patient underwent hemimandibulectomy and immediate reconstruction with a vascularized osteocutaneous fibula free flap. The final pathology was read as ameloblastic carcinoma in situ. Given the rarity of this disease in the pediatric population, this case report may be a valuable addition to the current literature.

Malignant Lesions in the Dentomaxillofacial Complex

Malignancies in the maxillofacial region are rare but comprise a broad spectrum of lesions. Given the potential for malignancies to mimic dental/sinus/temporomandibular joint pathology or remain asymptomatic, the judicious radiologist will be familiar with the initial and unique malignant changes affecting the dentition, periodontium, and supporting osseous structures on conventional film, dental, and sinus imaging. This article is meant to serve as a complement to the many excellent texts dedicated to advanced imaging techniques for the staging of known malignancies. The lesions discussed are a representative sample of malignancies involving hard tissues of the maxillofacial complex but are far from complete.

Rare case of ameloblastoma with pulmonary metastases

Ameloblastoma is a rare low-grade odontogenic tumor of epithelial origin. The World Health Organization (WHO) has defined malignant ameloblastoma (MA) as a histologically benign-appearing ameloblastoma that has metastasized. Treatment of the primary ameloblastoma usually consists of radical excision of the tumor and adjuvant radiotherapy. Chemotherapy should be used to treat metastases due to its indolent clinical course. Presented here is the case of a 43-year-old woman who was admitted to a hospital in 2006 with a large mass involving the neck and left mandible. The mass had formed over years and had been neglected. The woman was diagnosed with a primary ameloblastoma of the mandible. Surgical resection was performed, followed by adjuvant radiotherapy. In September 2016, she was admitted again, and the findings were consistent with metastases of the previously identified ameloblastoma to the lungs. The patient was evaluated for further chemotherapy with 6 cycles of cisplatin at a dose of 100 mg/m² on day 1, 5-FU at a dose of 1000 mg/m²/day on day 1-4 (3 wk), and pegylated filgrastim. The current case represents the classical course of a rare disease, which in this instance involved the common presentation of MA. This case is a valid incidence of MA based on the typical histology, findings from a lung biopsy, the immunohistochemical profile of the tumor, the typical clinical features, and a history of a previous primary disease.

Recurrence and cancerization of ameloblastoma: multivariate analysis of 87 recurrent craniofacial ameloblastoma to assess risk factors associated with early recurrence and secondary ameloblastic carcinoma

OBJECTIVE

The recurrence and progression of ameloblastoma are unpredictable. Therefore, we examined the influence of clinical factors on recurrence time and analyzed the clinical factors associated with early recurrence and cancerization. We then developed a staging system to predict early recurrence and cancerization.

METHODS

All of the primary craniofacial ameloblastoma patients treated in Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine were recorded. There were 87 recurrent cases used to create a staging system and tested in a Cox regression analysis for risk factors associated with early recurrence or cancerization following surgery.

RESULTS

There were 890 craniofacial ameloblastoma patients, and 72 cases had recurrence. There were also 15 cases with cancerous recurrence. The overall recurrence rate was 9.78%, and the cancer rate was 1.69%. The primary cases were classified into the following 3 stages based on clinicopathological features: stage I, the maximum tumor diameter ≤6 cm; stage II, the maximum diameter of tumor >6 cm or tumor invasion to the maxilla sinus/orbital floor/soft tissue; and stage III, tumor invasion of the skull base or metastasis into regional lymph nodes. When the method of surgery was controlled by partial correlation, the staging had significance with recurrence time (P=0.004). The Cox analysis showed the tumor stage was correlated with recurrence time (P=0.027) and cancerization time (P=0.002). However, the surgical method did not influence the recurrence time when adjusted for cofounding variables.

CONCLUSIONS

Tumor larger than 6 cm and invasion to soft tissues or adjacent anatomical structures are associated with early recurrence. This staging system can be used to predict the risk factors of early recurrence and cancerization in ameloblastoma patients.

Ameloblastic carcinoma of the maxilla: A case report and an updated review of the literature

Ameloblastic carcinoma (AC) is an uncommon malignant odontogenic tumor that can be difficult to differentiate from ameloblastoma and can arise directly as an undifferentiated lesion or from a pre-existing benign lesion. The current study presents a novel case of primary maxillary AC and review the literature on AC of the maxilla. The review of the literature indicates that secondary tumors and posterior localization are associated with a higher tendency for recurrence and, often, multiple recurrences. Surgical therapy, eventually followed by radiotherapy, is the treatment modality most frequently applied, while the role of chemotherapy remains unclear. Several new cases of maxillary AC have been recently described in literature, making this pathology more frequent than previously considered; this is perhaps an indication of an increased diagnostic sensibility, rather than a real increase in the incidence of the disease itself.

Survival and Prognosis for Malignant Tumors of Odontogenic Origin

Objective

Determine survival and factors affecting survival for patients with malignant tumors of odontogenic origin.

Study Design

Retrospective analysis of the National Cancer Institute’s SEER database (Surveillance, Epidemiology, and End Results).

Setting

Tertiary medical center.

Subjects and Methods

All cases of malignant tumors of odontogenic origin were extracted from the SEER database for the period of 1973 to 2011. Demographic, tumor-specific, and survival data were tabulated and Kaplan-Meier survival analysis conducted according to histopathologic results. Cox regression analysis stratified for histopathology was conducted to determine factors that influenced survival.

Results

A total of 308 cases of malignant tumors with odontogenic origin were analyzed. Malignant ameloblastoma accounted for 59.7% of cases, followed by malignant odontogenic tumor (35.4%; including odontogenic carcinoma, odontogenic sarcoma, primary intraosseous carcinoma, and ameloblastic carcinoma) and ameloblastic fibrosarcoma (2.9%). The overall mean and median were 229 and 227 months, respectively, while the 5-year survival rate was 81% for the entire cohort. Malignant ameloblastoma exhibited the best mean survival (237 months), whereas malignant odontogenic tumor (139 months) and ameloblastic fibrosarcoma (42 months) had lower mean survival rates. Younger age, surgery with adjuvant radiation, and smaller tumor size were found to improve survival.

Conclusions

Significantly different survival can be expected depending on individual tumor histopathology, tumor size, age at diagnosis, and treatment modality.

Ameloblastomas of the mandible and maxilla

PURPOSE OF REVIEW

This review focuses on issues in managing ameloblastomas of the mandible and maxilla. We will refer to current practice in the treatment of ameloblastomas based on the available evidence.

RECENT FINDINGS

Recent reviews have been trying to establish natural history, growth patterns and malignant potential. This provides the clinicians and the patients with useful prognostic information. Controversies in management of ameloblastomas in relation to the type, age and site exist. This paper aims to categorize these issues. More recently, the authors have adopted the staged treatment approach as an additional step to ensure margin clearance.

SUMMARY

Current evidence favours radical resection to provide better control rates. This applies to maxillary lesions of all ages, and solid mandibular lesions in adults (>18 years) where growth has ceased and the patient has matured enough to withstand the impact of resection and reconstruction. Conservative management is advocated for unicystic lesions with good control rates. In children and adolescents, a conservative approach is recommended. This approach aids to minimize both psychological and the impact on growth. Furthermore, most of the lesions are unicystic and the recurrent lesions have been shown to be much smaller and can be managed promptly within a good healthcare system.