Metastasizing Ameloblastoma – A perennial pathological enigma? Report of a case and review of literature

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.

Identification of circ_0089153/miR-608/EGFR p53 axis in ameloblastoma via MAPK signaling pathway

OBJECTIVES

This study investigated the role of circular RNAs (circRNAs) in the pathogenesis of ameloblastoma (AB), identifying potential novel targets for future targeted therapy.

MATERIALS AND METHODS

CircRNA and microRNA (miRNA) profiling in AB were built with microarrays. Six novel circRNAs were validated, circ-miRNA networks were delineated. Hsa-miR-608 was filtered over cross-comparison between database screening, miRNA microarray and validated. Circ-miRNA binding sponge was validated via luciferase reporter assay. Downstream mRNAs were screened. Regulation between miRNAs and mRNAs was confirmed in vitro. Gene interaction networks and circRNA-miRNA-mRNA interaction pathway enrichment analyses were established.

RESULTS

Six differentially expressed circRNAs were selected and validated. According to miRNAs and pathways predicted, six correlated miRNAs were selected, hsa-miR-608 was filtered and validated. The hsa_circ_0089153/hsa-miR-608 binding sponge was validated. Downstream gene interaction networks showed that EGFR and p53 had the strongest co-expression. In vitro transfection results confirmed the suppressive function of miR-608 and EGFR p53. Hsa_circ_0089153/hsa-miR-608/EGFR p53 interaction pathway enrichment analysis confirmed functions mainly enriched in MAPK and related signaling pathways regulating AB progression.

CONCLUSIONS

Six novel circRNAs were identified. Hsa_circ_0089153/hsa-miR-608 sponging was validated, hsa-miR-608 downregulated EGFR and p53, which might further regulate cell proliferation, differentiation, apoptosis, and cell cycle processes via the MAPK signaling pathway.

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.

A Rare Presentation of Ameloblastic Carcinoma of the Sinus Cavity and Skull Base

Ameloblastic carcinoma (AC) is an exceedingly rare odontogenic cancer about which there is limited information in the literature. We present a case of AC originating in the sinus cavity and extending to the skull base in a patient in the first trimester of pregnancy. Diagnostic work up was complicated by this pregnancy, which delayed radiation exposure with imaging. Once scans were obtained, diagnosis was further complicated by the radiographic similarities between possible lung metastases and previously undiagnosed sarcoid nodules. After thorough work up to rule out metastatic disease, the patient was successfully treated with primary surgical resection followed by adjuvant chemoradiation. The patient remained disease free at one year after therapy. This case demonstrates the importance of thorough work up in the diagnosis of AC, and is an opportunity to review the literature and discuss therapeutic methods to treat this rare, aggressive neoplasm.

An Ameloblastoma in the Middle Ear

An ameloblastoma is a locally aggressive odontogenic tumour that commonly develops from the odontogenic epithelium within the jawbone. Here we present for the first time a case of a rare primary ameloblastoma in the middle ear cavity, along with some consideration of its treatment and a new classification. A 65-year-old woman presented with a left middle ear cavity tumour. Pathological examination led to the diagnosis of an ameloblastoma. We resected the tumour along with an extensive part of the middle ear mucosa, which made it difficult to have an adequate margin. It is recommended that the remaining bone be ground 2-3 mm beyond the visible margin after resecting the gross tumour. Therefore, several cases are treated with conservative surgery, including physicochemical treatment. This factor should be considered when designing treatment strategies as good alternatives in cases where resection with an adequate margin is difficult.

Malignant ameloblastoma: a challenging diagnosis

Ameloblastoma is an uncommon and locally aggressive, benign, odontogenic tumor, with local recurrence when not adequately excised. A rare variant of this neoplasm with the benign features but accompanied with metastases has been described. This rare variant is malignant ameloblastoma and is known to have a poor prognosis. We present the case of a young woman who had recurrent mandibular tumors, which were resected twice and histologically reported as ameloblastoma. Four years later, she presented with pulmonary metastasis and atelectasis. A review of the literature on this very rare neoplasm was also performed.

Ameloblastoma-Clinical, radiological, and therapeutic findings

Ameloblastoma are the most common odontogenic tumor. As they usually do not form metastasis, they are considered as benign tumors with a locally invasive growth pattern and destruction of the jaws and the surrounding tissue (Oral Diseases, 23, 2017, 199). This article focuses on clinical, radiological, and therapeutic findings, which may influence diagnosis and treatment of ameloblastoma in the future.

Literature review of 86 cases of mandibular ameloblastic carcinoma

Ameloblastic carcinoma is considered to be a rare epithelial malignant neoplasm of odontogenic origin occurring mainly in the mandible. Ameloblastic carcinoma has been a topic of controversy regarding management from past many years. We reviewed 86 cases of mandibular ameloblastic carcinoma from 1981 to 2014, on the basis of the electronic search of peer-reviewed journals in MEDLINE (PubMed) database. Age, sex, tumor size, treatment delivered, recurrence, metastasis, follow-up period, and dead/alive status are tabulated, and the data are analyzed. The mean age was 43.47 years with standard deviation ± 21.09. The age range was between 15 and 91 years, and male to female ratio was 2.18:1. Knowledge gained from the present review would help in establishing the best therapeutic options for ameloblastic carcinoma, and it also encourages the further reporting of ameloblastic carcinoma.

Imaging characteristics of nodal metastases in paraganglioma, ameloblastoma and olfactory neuroblastoma: case reports and literature review

Paraganglioma, ameloblastoma and olfactory neuroblastoma are uncommon primary head and neck tumours. When nodal metastases from these tumours occur, they may present later than and with different imaging characteristics compared with squamous cell carcinoma (SCC), demonstrating appearances similar to the primary tumour type rather than features typical of metastatic nodal SCC. We present three cases in which imaging characteristics of nodal metastases in paraganglioma, ameloblastoma and olfactory neuroblastoma mimicked the primary tumour and discuss their implications for clinicoradiological follow-up.

Management Issues in the Treatment of an Ameloblastoma with an Atypical Presentation

Benign ameloblastoma (BA) is the most common tumor arising from the odontogenic epithelium. Surgical resection with adequate margins is the mainstay of treatment due to the high index of tumor recurrence when not completely excised. Although locoregional spread has been described in the literature, it is very uncommon. We describe the treatment and follow-up of a 22-year-old woman with multiple recurrences and locoregional spread of a mandibular ameloblastoma who was referred to our center after several tumor resections with subsequent reconstructions. After a complete macroscopical removal of a new recurrence, the mandible was primarily reconstructed. A local homolateral recurrence and a second lesion in the contralateral maxilla were detected after 1-year follow-up and accordingly treated. After 4 years the patient showed a new tumor in the temporal fossa and was reoperated. The histopathology was consistent with a BA in all cases. Even though it is rare, locoregional spread of BA has been reported previously. Recurrences discovered during follow-up may require further resections. A close follow-up is mandatory, and treatment of these cases may result demanding requiring a multiple team approach, including oncologists and radiotherapists.

Malignant odontogenic tumors: an update on selected tumors

This is an update on selected odontogenic malignancies. The article deals with aspects of recognized odontogenic carcinomas, odontogenic sarcoma and a yet unrecognized entity, sclerosing odontogenic carcinoma. Odontogenic malignancies are exceedingly rare, complicating a thorough understanding of the biologic behavior, reproducible standardized diagnostic criteria, appropriate classification and clinical management. Without the knowledge of the tumor's biologic behavior, adequate clinical management is difficult and patient outcomes uncertain. The histopathologic features are emphasized as well as the more recent biomarker findings. These recent advances may facilitate further understanding of this group of malignancies and provide useful stratification to guide patient management.

A single cervical lymph node metastasis of malignant ameloblastoma

INTRODUCTION

Cervical node metastasis of malignant ameloblastoma is extremely rare. Because of its rarity, there is no standard treatment modality in a single lymph node metastasis in malignant ameloblastoma.

MATERIALS AND METHODS

Eleven patients of malignant ameloblastoma involving a single cervical lymph node metastasis and one new case were reviewed. Neck treatment was classified into neck dissection and simple excision. Local nodal recurrence, distant metastasis and follow-up periods were investigated.

RESULTS

Eight patients were treated with neck dissection (group A) and four patients underwent a simple node excision (group B). Two patients in group A experienced multiple organ metastases such as liver and lung seven months and 13 years after neck dissection respectively. The other patients showed no recurrence and metastasis. In group B, there was no report of a regional neck recurrence and distant metastasis during follow-up of 1-7 years.

CONCLUSION

Multiple nodes metastasis requires a radical neck dissection; however, simple excision with close follow-up may be used in a single node metastasis in malignant ameloblastoma.