Surgical treatment of recurring ameloblastoma, are there options?

Treatment of benign maxillomandibular osteolytic lesions larger than 4 cm: A systematic review

OBJECTIVE

This systematic review aimed to assess the different treatments of benign maxillo-mandibular radiolucent bone lesions over 4 cm to propose a management algorithm.

STUDY DESIGN

A literature search was conducted using MEDLINE/PubMed, Scopus, Google Scholar, Virtual Health Library databases, and gray literature. Randomized or non-randomized clinical trials and case series with 10 or more patients with a minimum follow up of 1 year, published in French or English until August 2023, were included. The risk of bias was assessed for all papers included.

RESULTS

Of 1433 records identified, 22 were included in this review, reporting data from 1364 lesions. Ameloblastoma was the most common lesion (51.22%) and mandible was the most common site (81.21%). Initial conservative treatment was prevalent (71.04%). Recurrence was higher after conservative (13.8%) than after radical treatments (6.5%). Multilocularity, cortical perforation, dental element preservation were linked to a higher recurrence risk.

CONCLUSION

This study has shown importance of understanding specific characteristics and recurrence risk in benign maxillomandibular osteolytic lesions. Multidisciplinary team approval, personalized approach based on lesion type and patient are crucial. The presence of at least one risk factor could lead to therapeutic decision. Despite limitations, the study informed lesion management and provided precise recommendations.

Clinicopathologic Profile and Surgical Modalities in Mandibular Ameloblastoma: A Descriptive Study

BACKGROUND

Ameloblastoma is a benign neoplasm composed of epithelial tissue with invasive and infiltrative behavior at the local level and a high recurrence rate, with various histopathologic patterns and clinical forms. Approximately 85% of conventional ameloblastomas occur in the mandible, most often in the body, angle, and ascending ramus area. The treatment modalities include both conservative and radical treatments. Postoperative follow-up is most important in the treatment of ameloblastoma.

AIMS AND OBJECTIVES

To describe the clinicopathologic profile of mandibular ameloblastoma in patients undergoing different surgical modalities. The primary objective was to describe the clinicopathologic profile and surgical management of mandibular ameloblastoma in patients aged ≥18 years, who had reported to a tertiary dental care center for follow-up during the study period. The secondary objective was to describe the distribution of comorbidities associated with different surgical modalities and reconstructive methods.

SUBJECTS AND METHODS

A total of 34 patients with mandibular ameloblastoma who underwent various surgical modalities between 2011 and 2021 were studied. Information was collected using a predesigned proforma and statistically analyzed.

RESULTS

Thirty-four review cases of ameloblastoma were included in the study. The patients were analyzed concerning age, sex, site, size, clinical presentation, radiographic pattern, histopathologic subtype, type of surgery, and associated comorbidities. Most cases of mandibular ameloblastoma involve the age of 16 to 55 years. The mean age of occurrence was found to be 35.5±13.2. A female preponderance, a tumor size range of 2 to 4 cm, a multicystic variant, involvement of the mandibular body in the premolar-molar area, root resorption, cortical perforation, and a follicular type of histopathologic pattern were the common presentations. Isolated anterior tumors restricted to the incisor/canine region were not found. The common surgical modalities undertaken were conservative methods such as enucleation, and chemical cauterization, and radical methods such as marginal mandibulectomy and segmental resection. Reconstruction using a titanium plate or free fibular graft was performed in the indicated cases. The common comorbidities included difficulty in chewing and loss of facial contour. Recurrence after surgical treatment was rare. Only 9% of cases developed a recurrence within 5 years. No recurrence was noted in cases treated with radical treatment, whereas 50% of cases treated with conservative methods showed recurrence.

CONCLUSION

The age of occurrence, site, and size of the tumor, cortical perforation, root resorption, histopathologic type, and radiographic patterns are widely considered factors in devising a treatment plan for mandibular ameloblastoma. However, there may be rare instances where these tumors behave differently regardless of their innocuous clinicopathologic presentation. Surgical procedures such as segmental resection and marginal mandibulectomy were found to be promising for the eradication of the tumor, and prevention of recurrences and metastasis. However, conservative measures such as enucleation and chemical cauterization were fraught with an increased risk of tumor recurrence and metastasis. Future studies with a larger sample size should focus on the clinicopathologic characteristics of ameloblastoma to elucidate its varied behavior and develop newer and advanced treatment modalities that would provide better surgical and postsurgical outcomes in affected patients.

Curettage combined with bone cavity opening reduces recurrence of the mandibular conventional ameloblastoma and effectively preserves the mandible: a retrospective study

BACKGROUND

Patients with mandibular conventional ameloblastoma undergoing radical surgical treatment experience greater trauma and often find it challenging to accept, whereas conservative therapy is associated with a higher recurrence rate. In this study, we have improved traditional conservative treatment for mandibular conventional ameloblastoma by curettage combined with bone cavity opening (Cur/BCO). This retrospective study aimed to evaluate the effectiveness of the Cur/BCO treatment by comparing its recurrence rate and bone mineral density (BMD) growth rate with the traditional conservative treatment approach.

METHODS

A total of 40 patients, meeting the study's inclusion and exclusion criteria from 2012 to 2020, were screened, with 20 in the modified group and 20 in the traditional group. ImageJ (RRID: SCR_003070) software was employed for measuring image indices. All data were analyzed using T-test, Chi-square test and Fisher exact test in SPSS 26.0 (p = 0.05).

RESULTS

The incidence of recurrence was significantly lower in the modified group, at only 5%, compared to 35% in the traditional group (p < 0.05). Regarding bone mineral density (BMD) growth rate, the average value in the modified group was 0.0862 ± 0.2302 (/month), significantly higher than the average value of 0.0608 ± 0.2474 (/month) in the traditional group (p < 0.05).

CONCLUSIONS

In this study, it was found that the recurrence rate of the modified conservative treatment (Cur/BCO) was lower than that of the traditional conservative treatment for managing mandibular conventional ameloblastoma. Furthermore, the BMD growth rate was quicker in the modified group. Thus, Cur/BCO could be considered as a viable option for the conservative treatment of mandibular conventional ameloblastoma.

Recurrent Ameloblastoma: Long Term Outcomes with Free Fibular Bone Graft

Ameloblastoma is a locally aggressive benign neoplasm of jaw that has high propensity to recur. Pathological subtype and intent of surgical excision during primary surgery are two factors that are known to affect the prognosis in these cases. Nevertheless, there are hardly any studies which have studied recurrent ameloblastoma cases. Apart from sharing a tertiary care cancer center's experience in managing a series of recurrent ameloblastoma cases, we discuss some of the recent literature related to pathophysiology and principles related to their surgical management. Retrospective chart review of all those recurrent ameloblastoma cases which were operated between October 2013 and January 2016 and were subsequently followed up for minimum of 3 years. Total of 9 recurrent ameloblastoma cases were operated in the study period. All our patients had less-radical or non-curative intent surgical treatment in the past, and current treatment consisted wide excision of the involved segment of mandible with free fibular reconstruction. Among the 6 patients who were followed up for more than 3 years, none developed recurrence at 56.5 months of mean follow up duration. Almost all these patients had optimal results with good quality of life in terms of oral speech intellectuality and cosmetic perception of self. Complete excision of the involved segment of bone with reconstruction using the composite free fibular graft can provide optimal functional outcomes and can significantly lessen the chances of further recurrences.

Hypoxia enhances basal autophagy of epithelial-derived ameloblastoma cells

Ameloblastoma is a locally aggressive odontogenic tumor. Etiopathogenesis and locally aggressive growth properties of ameloblastoma can be attributed to a hypoxic microenvironment conducive to tumor cell survival. Epithelial-derived follicular ameloblastoma cells (EP-AMCs) display enhanced basal autophagy, but the interplay of hypoxia and autophagy in EP-AMCs survival and ameloblastoma recurrence is unclear. We evaluated differential expression of autophagic markers in primary and recurrent ameloblastomas and hypothesized that hypoxia-induced autophagy supports EP-AMC survival. Primary and recurrent ameloblastomas were comparatively assessed for expression levels of pan-cytokeratin, Vimentin, and autophagic markers SQSTM1/p62, LC3, and pS6. EP-AMCs compared with human odontoma-derived cells (HODCs) were subjected to severe hypoxia to determine the interplay of hypoxia and autophagic process in posthypoxia survival. Pan-cytokeratin and SQSTM1/p62 were expressed by both primary and recurrent ameloblastoma epithelial cells while the ameloblastoma connective tissues displayed weak reactivity to vimentin. Under hypoxia, EP-AMC expression levels of hypoxia-inducible factor (HIF)-1α, p62, and LC3 were increased while pS6 was decreased posthypoxia. The combined decrease in pS6 and enhanced LC3 in EP-AMCs under hypoxia indicate that EP-AMCs re-establish basal autophagy under hypoxia. Taken together, these suggest a possible role of LC3-associated phagocytosis (LAP) in ameloblastoma cell survival.

Comparison of Immunohistochemistry and DNA Sequencing for BRAF V600E Mutation Detection in Mandibular Ameloblastomas

This study aimed to investigate the presence of BRAF V600E mutation in mandibular ameloblastoma by comparing the results of molecular detection and immunohistochemical analysis. A 128 cases of mandibular ameloblastoma and 30 cases of dentigerous cyst (control group) were selected for analysis. Detection of BRAF V600E mutation was performed with immunohistochemistry (IHC) and polymerase chain reaction techniques. Clinico-pathologic data were collected in order to investigate possible associations with the mutation. Of the 128 cases submitted to IHC, 81.2% (108 cases) showed positivity for anti-BRAF V600E antibody, whereas 24 were negative (18.8%). Molecular analysis of the BRAF V600E mutation by polymerase chain reaction was possible in 116 cases due to DNA quality. Of these cases, 96 were positive (82.8%) and 20 negative (17.2%). All cases of dentigerous cyst were negative for BRAF V600E mutation in both techniques. Considering the sequencing as a gold standard method, the receiver operating characteristics curve analysis showed sensitivity of 0.99 and specificity of 1 (area under the curve=0.995, standard error=0.006; P<0.001; 95% confidence interval=0.983 to 1). We also tested the agreement between the techniques by using the Cohen's κ coefficient, with κ being 0.97 (P<0.001). IHC is a reliable test for identifying the BRAF V600E mutation in ameloblastomas, presenting advantages such as being more frequently used in surgical pathology laboratories and requiring fewer critical steps for paraffin-embedded tissue compared with molecular biology techniques.

Synchronous occurrence of odontogenic keratocyst and ameloblastoma: A case report and review of the literature

Odontogenic keratocyst (OKC) and ameloblastomas are distinct histopathologically diagnosed odontogenic lesions of the oral cavity. Both are primarily located in the posterior regions of the mandible, however, they can involve the maxilla as well. The occurrence of both an OKC and ameloblastoma in a patient is very uncommon. This case demonstrated such a lesion in the mandible of a 57 years old female. The diagnostic work-up and features of both lesions are illustrated with special focus on histopathological variances distinguishing OKC from ameloblastoma with the support of immunohistochemistry. This case highlights the importance of identifying accurate diagnoses for such lesions which may prompt clinical implications. Clinico-pathologic understanding of both lesions signifies the need for careful management plan and prevention of recurrence. Previously reported simultaneous occurrences of odontogenic cysts and/or tumors in the oral cavity are also reviewed.

A modified surgical approach for the treatment of mandibular unicystic ameloblastoma in young patients

BACKGROUND

Unicystic ameloblastoma is a distinct clinicopathological entity with its cyst-like radiographic appearance and occurrence in the mandible of young patients. Surgical resection of the mandible leads to jaw deformity and challenging reconstruction burden, especially among young patients. Conservative treatment, however, results in less serious function and esthetic impairment.

PURPOSE

We aimed at evaluating dredging method as an alternative conservative surgical approach in young patient with large unicystic ameloblastoma.

PATIENTS AND METHODS

Twenty patients (n=20) with histologically-diagnosed unicystic ameloblastoma were recruited for this prospective study. The surgical treatment protocol comprised an initial deflation (marsupialization) step, followed by later enucleation and subsequent repeated separate dredging procedures.

RESULTS

The study population comprised 16 males and 4 females. The average age at the time of diagnosis was 18.5 years. At the last follow-up period, achievement of normal mandibular bone contour with no radiographic signs of recurrence was evident.

CONCLUSION

The dredging method as a modified surgical technique may represent a reliable approach for management of unicystic ameloblastoma in young patients.

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.

Global incidence and profile of ameloblastoma: A systematic review and meta-analysis

OBJECTIVES

To evaluate the global incidence of ameloblastoma and to provide a profile of ameloblastoma patients.

MATERIAL AND METHODS

A systematic review and meta-analysis was conducted. Searches were performed in PubMed, EMBASE, SCOPUS, and Web of Science for articles published from 1969 to 2018 for the global incidence and from 1995 to 2018 for the profile of ameloblastoma patients.

RESULTS

Seven studies on the incidence rate of ameloblastoma were included in the meta-analysis. These studies only covered Europe, Africa, and Australia. The pooled incidence rate was 0.92 per million person-years (95% CI: 0.57-1.49), with significant heterogeneity between studies. Forty-two articles provided profile data of 6,446 ameloblastoma patients. Mean age was 34 years and the peak age incidence in the third decade of life. In Europe and North America, ameloblastoma mostly occurred at an older age when compared to Africa and South America. A slight male preference (53%) was found, and the mandible appeared to be the preferred site. The most common type of ameloblastoma was multicystic. The histopathologic patterns were mostly follicular and plexiform.

CONCLUSIONS

This is the first study assessing the global incidence of ameloblastoma. The pooled incidence rate was determined to be 0.92 per million person-years.

Surgical management of ameloblastoma. Review of literature

Background

Ameloblastoma is an odontogenic tumor that represents 1% of all tumors in the oral cavity and it is clinically classified in three types. Currently, solid and multi-cystic are considered locally aggressive, with high recurrence rates with conservative treatment.

Material and Methods

Objective of the present review is to assess whether the surgical treatment should be conservative or radical. English articles published between 2009-2014, with available summary and in humans were included.

Results

241 articles were found, 188 were excluded because analyzing. 53 articles were analyzed and finally 14 were selected for this review.

Conclusions

The optimal surgical treatment of ameloblastoma should minimize recurrences, restore function and aesthetic and present a minimal morbidity in the donor area. Surgical planning must be performed based on the patient comorbidities, the size and location of the tumor, the techniques available for reconstruction and the surgeon’s experience-Radical surgery appears to be the most recommended option in multicystic / solid and advanced unicystic tumors, along with long-term follow-up for the possibility of recurrence beyond 10 year. Conservative surgery combined with a support technique and long-term follow-up is reserved for the unicystic and multicystic / solid types if small extension. Prospective and randomized studies for ameloblastoma are recommended.

Key words:Ameloblastoma, surgery, enucleation, radical.

Oral Rehabilitation of Patients with Ameloblastoma of the Mandible. Clinical Results in Three Patients with Different Bone Reconstruction Techniques

Background:

Ameloblastoma is the second most common odontogenic tumor. It shows a locally aggressive behavior, with a high level of recurrence. Wide resection of the jaw is recommended for treatment of ameloblastoma. However, radical surgery causes an abnormal mandibular movement, facial asymmetry, and masticatory dysfunction.

Methods:

Three cases of different types of ameloblastoma is presented, with different reconstruction techniques including Non-Vascularized Bone Graft (NVBG), Osteocutaneous Fibula Free Flap (OFFF), and Deep Circumflex Iliac Artery flap (DCIA).

Results:

In all three cases the tumor site was successfully reconstructed to obtain very good esthetic results as well as functional oral rehabilitation with implants and fixed prosthetics for optimal masticatory function.

Conclusion:

For reconstruction of the mandible, we prefer bone grafts from the iliac crest. The natural curvature and variable bone height offer a very good reconstruction of the defect.

Is conservative surgery a better choice for the solid/multicystic ameloblastoma than radical surgery regarding recurrence? A systematic review

PURPOSE

Determine if conservative surgery of primary solid/multicystic ameloblastoma (SMA) is capable of decreasing the recurrence rate as effectively as radical surgery.

METHODS

We searched in MEDLINE, Web of Science, Scopus and Cochrane Library for original studies reporting on the conservative or radical treatment of primary SMA and the related recurrence rate. All selected data were independently assessed. Meta-analysis was performed and the Relative Risk (RR) of recurrence with a confidence interval of 95% was the effect measure. P value for the summary effect of < 0.05 was considered statistically significant.

RESULTS

The 2647 records retrieved were reduced to 7 studies to be qualitatively assessed and 4 studies were included in the meta-analysis. RR of 1.88 [0.59, 5.95] of the pooled values pointed that recurrence rate after the conservative surgery is neither comparable nor lower than the radical surgery (P = 0.28).

CONCLUSIONS

Conservative surgery does not reduce the recurrence rate as efficiently as radical surgery for primary SMA. However, there is not enough evidence to support this statement.

Successful conservative treatment of a mandibular unicystic ameloblastoma: 13-year follow-up

Ameloblastoma is an uncommon, locally aggressive benign odontogenic tumor and can reach considerable dimensions causing facial deformity and functional impairment. They are characterized by local aggressiveness. It is recommended that maxillary ameloblastomas be treated aggressively due to proximity of various vital structures. Conservative treatments such as marsupialization, enucleation and curettage while preserving bone integrity seem to be associated with a high rate of recurrence. Treatment evaluation of ameloblastomas is a complex issue, as ideally it should not be so destructive due to the benign nature of this lesion, but should be extensive enough to avoid recurrences. The present study is about a clinical case of a 16-year- old man with a unicystic ameloblastoma treated successfully with marsupialization. Patient was followed up every 12 months. About 13 years after diagnosis, the patient is clinically healthy and radiographically it is possible to observe evidence of bone repair.

Key words:Odontogenic tumors, ameloblastoma, marsupialization, unicystic.

Ameloblastoma: A retrospective analysis of 31 cases

Aims and objective

To evaluate the surgical treatment given and do a regular follow up to study the recurrence rate and complications of ameloblastoma in our institution.

Materials and methods

A total of 31 cases of various subtypes of ameloblastoma, treated with different modalities, in the Department of OMFS, were recalled for a follow up & radiographs were taken along with the clinical examination for any recurrence or complications such as fracture/exposure of the reconstruction plate, loosening of the screw, infection of the graft, any draining sinus/signs of infection.

Results

Two of our patients had fractured reconstruction plate, one patient developed infection, one patient complained of screw exposure and two other patients had infection of the iliac graft.

Conclusion

We conclude that an adequate resection with a safe margin could be a treatment option and can be undertaken depending on the extent, location of the lesion and histopathologic variant.

The Pull-Through Technique: A Viable Option for Preserving the Inferior Alveolar Nerve during Surgical Resection

The aim of this study was to present a new surgical technique used to remove benign mandibular tumors with minimal damage to the inferior alveolar nerve. The pull-through technique was shown using an ameloblastoma surgical resection as an example. This technique consisted in the reconstruction of the lower jaw associating the resection of the lesion with nerve repair at the same surgical time. The resection was performed using the pull-through technique and the inferior alveolar nerve was preserved. After 6 months, the patient presented a recovery of approximately 80% of sensory function. The surgical technique presented should be considered an important method by which to produce a higher functional outcome to remove benign mandibular tumors with minimal damage to the inferior alveolar nerve and allows the maintenance of quality of life for the patient, as the consequences of this type of surgery are minimized.

Proceedings of the American Association of Oral and Maxillofacial Surgeons 2015 Research Summit

The Fifth Biennial Research Summit of the American Association of Oral and Maxillofacial Surgeons and its Committee on Research Planning and Technology Assessment was held in Rosemont, Illinois on May 6 and 7, 2015. The goal of the symposium is to provide a forum for the most recent clinical and scientific advances to be brought to the specialty. The proceedings of the events of that summit are presented in this report.

Enucleation combined with peripheral ostectomy: its role in the management of large cystic ameloblastomas of the mandible

AIM

Aggressive resection of a large mandibular cystic ameloblastoma may cause severe deformity and dysfunction, while simple enucleation may carry a high risk of recurrence. The purpose of this study was to evaluate, in terms of both recurrence and the preservation of contour and function, the effectiveness of enucleation combined with peripheral ostectomy (Enu/PO) in managing large mandibular cystic ameloblastomas.

MATERIALS AND METHODS

Fourteen patients who had large mandibular cystic ameloblastoma (11 unicystic, 3 multicystic) and had been treated with the Enu/PO were reviewed.

RESULTS

The follow-up period was 19-117 months. Using Enu/PO, mandibular continuity was preserved in all patients, and only one patient complained of permanent lip numbness. With bone regeneration, the thinned bone plate significantly thickened and the residual cavity shrank. No pathological fracture occurred. There was recurrence in 3 patients. Two recurrences were treated with radical surgery, and the other with Enu/PO. No new recurrence was found thereafter. All patients were satisfied with their facial appearance.

CONCLUSIONS

The Enu/PO technique is excellent in preserving appearance and functions and with a low risk of recurrence, is a reliable option for the management of large mandibular cystic ameloblastomas.