Maxillary ameloblastoma: a retrospective study of 13 cases

Factors Associated with Recurrence of Ameloblastoma: A Scoping Review

PURPOSE

This scoping review aimed to identify factors associated with the recurrence of ameloblastoma.

METHODS

Systematic searches were conducted in PubMed, Scopus, and EMBASE, based on the board research question: "What factors are related to the recurrence of ameloblastoma?". English-language observational studies addressing the risk and preventive factors associated with recurrent ameloblastoma were included and data were extracted.

RESULTS

Eighty-three retrospective observational studies met the inclusion criteria. The identified prognostic factors for recurrence included: (1) Tumor size/diameter/volume, (2) cortical bone perforation/ soft tissue invasion, (3) multilocular radiolucency, (4) impacted tooth-involving lesions, (5) root resorption, (6) WHO classification - conventional (solid/multicystic) ameloblastoma, (7) histological subtype - mural invasion of unicystic ameloblastoma, (8) conservative treatment modalities - simple enucleation, curettage, and marsupialization, and (9) non-extraction/preservation of involved teeth. No strong evidence linked immunohistochemical expression to recurrence. Interestingly, BRAF p.V600E remained controversial in terms of recurrence, despite being a frequent finding in ameloblastoma.

CONCLUSION

Certain clinical characteristics, radiographic findings, histological subtypes, and treatment choices of ameloblastoma can help identify patients at high risk of recurrence. Further prospective studies to evaluate the prognostic factor model and research on immunohistochemistry are required.

Maxillary Ameloblastoma with Local Recurrence, Orbital Invasion, and Systemic Metastases: A Case Report and Review of the Literature

Introduction

Maxillary ameloblastoma is a rare, slow-growing odontogenic tumor that can recur after surgical excision, be locally aggressive, and rarely develop systemic metastases. We describe the course and management of a patient with recurrent maxillary ameloblastoma with orbital invasion and systemic metastases, the fourth case of its kind to be described in the literature.

Case Presentation

A 50-year-old female presented with left hyperglobus. A diagnosis of maxillary ameloblastoma was made based on biopsy and neuroimaging with MRI and CT. Surgical management included partial maxillectomy with orbital floor reconstruction, given the orbital invasion. Three years later, left hyperglobus recurred, and the patient was found to have orbital recurrence and lung metastases on PET imaging. The lung and orbital lesions have responded well to chemoradiation therapy without surgical intervention.

Conclusion

Maxillary ameloblastoma is a rare tumor that typically arises from odontogenic tissues. Though considered benign, they can recur and in the case of our patient, metastasize. Complete surgical excision with wide surgical margins is associated with a shorter average time to recurrence and a lower incidence of metastasis. Cases of metastasis are managed with chemotherapy with or without adjuvant radiotherapy. Precision medicine may play a role in managing this entity in the future, given the discovery of differing profiles of maxillary ameloblastoma compared to mandibular. Ophthalmologists should be aware of this tumor as it can invade the orbit, resulting in significant ocular morbidity and mortality.

Maxillary Ameloblastoma: A Review With Clinical, Histological and Prognostic Data of a Rare Tumor

Diagnosis of odontogenic tumors can be challenging due to their rarity and diverse morphology, but when arising near the tooth, the diagnosis could be suspected. When their location is not typical, like inside the paranasal sinuses, the diagnosis is less easy. Maxillary ameloblastomas are exceedingly rare with only sparse information on their epidemiological, histological and genetic characteristics. The aim of this report is to thoroughly review the available literature in order to present the characteristics of this tumor. According to available data, maxillary ameloblastomas can occur in all ages but later than mandible ones, and everywhere within the maxillary region without necessarily having direct contact with the teeth. No sex preference has been shown. The most common histological patterns seen in this location are the follicular and plexiform ones. Maxillary ameloblastomas are locally aggressive neoplasms, thus therapy aims for excision including normal bone beyond the lesion. In contrast to mandible ameloblastomas, maxillary ones most commonly show mutations of the SMO gene. Furthermore, differential tumor diagnosis is thoroughly discussed in the present review.

Adjunctive Strategies for Benign Maxillofacial Pathology

Benign cysts and neoplasms of the maxillofacial region can vary in behavior, with some growing rapidly and resulting in destruction of surrounding structures. Despite their benign histology, many require often-morbid treatment to prevent recurrence of these lesions. Several less invasive and adjunctive medical treatments have been developed to lessen the morbidity of surgical treatment. As the molecular and genomic pathogenesis of these lesions is better understood, more directed treatments may lessen the burden for patients.

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.

Ameloblastomas of the mandible and maxilla

Ameloblastoma is a histologically benign but locally aggressive tumor of the jaws. We conducted a retrospective cohort study to review the clinical, radiologic, and pathologic features of patients with ameloblastoma of the mandible and maxilla and to report the outcomes of treatment. Our study population was made up of a series of 30 consecutively presenting patients-15 men and 15 women, aged 19 to 81 years (median: 61.5)-who had undergone their primary treatment of ameloblastoma of the mandible or maxilla at Memorial Sloan Kettering Cancer Center from January 1987 through December 2012. In addition to demographic data, we compiled information on clinical characteristics, imaging findings, the type of surgery, surgical margins, adjuvant treatments, histologic patterns, length of follow-up, time to recurrence, treatment of recurrence, and factors that had an influence on recurrence. All but 2 patients with negative margins were cured. Favorable outcomes were associated with the administration of adjuvant postoperative radiotherapy for patients with positive margins and a repeat resection for patients with recurrences. Complete excision with negative margins, however, remains the gold standard for curative treatment.

Maxillary ameloblastoma: results of the treatment in 11 patients

Introduction: Surgery of maxilla ameloblastoma is mutilating and the tumor propensity for recurrence high. Patients and Methods: The oral and visual functions, facial morphology and tumor recurrence in 11 patients after maxillary ameloblastoma surgery are retrospectively reviewed. Results: Facial morphology was satisfactory in 7 patients who had all tumor removal by a type 1 or 2A maxillectomy and surgical wound closure. Out of these patients, 4 who had dental rehabilitation by conventional prosthesis presented satisfactory mastication. Four patients subjected to the tumor removal by a type 3 maxillectomy had all facial asymmetry. Out of these, 1 patient who did not have the orbital floor defect repair presented diplopia and enophtalmos, 2 patients subjected to the palate defect repair by a prosthetic obturator or oral mucosa had elocution impairment. The tumor recurrence occurred in 2 patients after tumor enucleation and in 1 patient after radical surgery out of 8 patients who had a postoperative follow-up. Discussion: In ameloblastoma surgery, achieving both the tumor recurrence prevention and a satisfactory facial reconstruction is challenging. Conclusion: Avoiding the tumor recurrence should be the major goal when patient post-surgical follow-up cannot be guaranteed.

Marsupialization of mandibular cystic ameloblastoma: Retrospective study of 7 years

BACKGROUND

This retrospective study investigated the reduction rate and speed of shrinkage after marsupialization in mandibular cystic ameloblastoma and clarified whether marsupialization is appropriate for unicystic ameloblastoma and multicystic ameloblastoma.

METHODS

Sixty-three patients with mandibular cystic ameloblastoma were initially treated with marsupialization. Premarsupialization and postmarsupialization panoramic radiographs were reviewed for reduction rate and speed of shrinkage, and then were evaluated with age, sex, tumor location, and tumor type.

RESULTS

The overall recurrence rate was 4.5% (2/44). The average reduction rate after marsupialization was 65.6%. No significant difference was found between unicystic ameloblastoma and multicystic ameloblastoma in reduction rate. The speed of shrinkage of unicystic ameloblastoma was significantly faster than that of multicystic ameloblastoma (P < .05). Similarly, patients with multicystic ameloblastoma had longer marsupialization periods than those with unicystic ameloblastoma (P < .05).

CONCLUSION

Marsupialization is effective in reducing tumor size for both unicystic ameloblastoma and multicystic ameloblastoma. Marsupialization plus second-stage curettage is recommended as the primary treatment for mandibular cystic ameloblastoma.

Maxillary ameloblastoma: Factors associated with risk of recurrence

BACKGROUND

Maxillary ameloblastomas are rare and associated with an aggressive course because of the anatomic composition of the maxilla and adjacent structures. The risk factors associated with recurrence were analyzed in this retrospective study.

METHODS

Cases of maxillary ameloblastoma reported in a tertiary hospital from 2005 to 2015 were analyzed to identify clinicopathological and radiological factors associated with recurrence using univariate and multivariate Cox regression analyses.

RESULTS

A total of 890 patients with ameloblastomas were treated in this study, of whom only 51 (5.7%) had maxillary ameloblastomas. The median follow-up period was 56 ± 28.65 months. Of the maxillary ameloblastomas, 29 (56.8%) were primary and 22 (43.1%) were recurrent. Soft tissue or maxillary sinus invasion and primary or recurrent tumor status were risk factors significantly associated with recurrence in the univariate analyses (p = .006 vs p = .025, respectively), whereas the association between recurrence and surgical methods was borderline significant (p = .08). The multivariate Cox regression analysis showed that soft tissue or maxillary sinus involvement was significantly associated with recurrence (p = .023).

CONCLUSION

Recurrent tumors and tumors with soft tissue or maxillary sinus involvement were risk factors for recurrence among patients with maxillary ameloblastoma. © 2017 Wiley Periodicals, Inc. Head Neck 39: 996-1000, 2017.

Odontogenic Cysts and Tumors

This article presents various odontogenic cysts and tumors, including periapical cysts, dentigerous cysts, odontogenic keratocysts, orthokeratinized odontogenic cysts, lateral periodontal cysts, glandular odontogenic cysts, ameloblastomas, clear cell odontogenic carcinomas, adenomatoid odontogenic tumors, calcifying epithelial odontogenic tumors, squamous odontogenic tumors, ameloblastic fibromas, ameloblastic fibro-odontomas, odontomas, calcifying cystic odontogenic tumors, and odontogenic myxomas. The authors provide an overview of these cysts and tumors, with microsopic features, gross features, differential diagnosis, prognosis, and potential diagnostic pitfalls.

Maxillary Ameloblastoma with Orbital Involvement: An Institutional Experience and Literature Review

PURPOSE

To describe 8 patients with orbital involvement by ameloblastoma and to review the literature on this topic.

METHODS

The electronic medical records and pathology databases of the Hospital of the University of Pennsylvania were searched to identify all patients with histopathologically confirmed ameloblastoma diagnosed between 1990 and 2015. PubMed database was searched for all well-documented cases of maxillary ameloblastoma and ameloblastic carcinoma ex-ameloblastoma with orbital involvement published in the English literature. The information collected on the compiled 23 patients included age, sex, clinical presentation, imaging findings, management, tumor histopathologic features, and follow up.

RESULTS

Review of medical records identified 8 patients with orbital involvement by ameloblastoma. Literature search yielded 15 patients with well-documented orbital involvement by ameloblastoma. Most tumors occurred in men (19 of 23, M:F = 4-5:1) with an average age of 56 years. The overall rates of recurrence, visual compromise, death, and confirmed disease-related mortality were 70% (16/23), 26% (6/23), 39% (9/23), and 22% (5/23), respectively. The initial surgical approach correlated with prognosis. The rates of recurrence, orbital exenteration, and mortality in the cohort managed with conservative surgery or partial maxillectomy were 57% (8/14), 29% (4/14), and 50% (7/14), respectively. In contrast, the patients initially managed with a radical resection had substantially lower frequencies of tumor recurrence (2/7, 29%), exenteration (1/7, 14%), and death (1/7, 14%). Malignant transformation to ameloblastic carcinoma occurred in the setting of recurrent disease in 3 patients and in 1 patient with prolonged duration of symptoms, suggestive of a long-standing tumor.

CONCLUSIONS

Maxillary ameloblastoma can rarely involve the orbit, leading to significant ocular morbidity and occasional mortality. Prompt radical resection of the tumor has the potential to decrease the likelihood of recurrence and visual compromise, and can improve survival.

Ameloblastoma: demographic data and treatment outcomes from Melbourne, Australia

BACKGROUND

There is a lack of published data on the demographics and treatment outcomes of ameloblastomas treated in Australia. Our objective was to collect this data and compare the findings to other international studies.

METHODS

A retrospective study of 42 patients with ameloblastoma was conducted at The Royal Melbourne Hospital, Australia. Data on the demographic features, management techniques (ablative and reconstructive), and outcomes were collected and analysed.

RESULTS

The majority of tumours were solid/multicystic (81%) and occurred most commonly in the mandible (80.5%). Unicystic ameloblastomas affected a younger age group, with Type 3 being the most common subtype. Overall, the recurrence rate for solid/multicystic ameloblastomas was 14.7%; however, radical surgery was found to have a significantly lower recurrence rate when compared to conservative management (p=0.015), with a mean of 51 months follow-up. Results indicated that vascularized free-flaps had fewer postoperative complications than non-vascularized bone grafts; however, the differences did not reach statistical significance.

CONCLUSIONS

This is the largest clinicopathological study regarding ameloblastoma management from Australia, and our results support the current literature in recommending radical surgery for the treatment of solid/multicystic and Type 3 unicystic tumours.

Establishing the natural history and growth rate of ameloblastoma with implications for management: systematic review and meta-analysis

Background

Ameloblastoma is the second most common odontogenic tumor, known to be slow-growing, persistent, and locally aggressive. Recent data suggests that ameloblastoma is best treated with wide resection and adequate margins. Following primary excision, bony reconstruction is often necessary for a functional and aesthetically satisfactory outcome, making early diagnosis paramount. Despite earlier diagnosis potentially limiting the extent of resection and reconstruction, an understanding of the growth rate and natural history of ameloblastoma has been notably lacking from the literature.

Method

A systematic review of the literature was conducted by reviewing relevant articles from PubMed and Web of Science databases. Each article’s level of evidence was formally appraised according to the Centre of Evidence Based Medicine (CEBM), with data from each utilized in a meta-analysis of growth rates for ameloblastoma.

Results

Literature regarding the natural history of ameloblastoma is limited since the tumor is immediately acted upon at its initial detection, unless the patient voluntarily refuses a surgical intervention. From the limited data, it is derived that the highest estimated growth rate is associated with solid, multicystic type and the lowest rate with peripheral ameloblastomas. After meta-analysis, the calculated mean specific grow rate is 87.84% per year.

Conclusion

The growth rate of ameloblastoma has been demonstrated, offering prognostic and management information, particularly in cases where a delay in management is envisaged.

The utility of a combined endoscopic and transoral resection of maxillary ameloblastoma

BACKGROUND

This report describes the role of endoscopic resection of maxillary ameloblastoma.

CASE REPORT

A 43-year-old female presented with a maxillary ameloblastoma filling the left maxillary sinus and extending into the left nasal cavity and nasopharynx. The sinonasal portion of the tumor was resected endoscopically. A limited transoral resection was then performed to resect the involved teeth and surrounding margin allowing for primary closure without any tumor recurrence or oronasal fistulas on follow-up.

CONCLUSION

Transnasal endoscopic surgery for odontogenic maxillary tumors is less invasive and can reduce the morbidity associated with traditional maxillectomy.

Intraosseous ameloblastoma

Ameloblastomas are benign slow-growing aggressive neoplasms with a poorly understood potential for rare metastasis. They are capable of reaching large sizes with extensive local bone erosion and destruction. They are composed of a mixture of ameloblastic epithelium and mesenchyme and arise from rests of outer and inner enamel epithelium and dental lamina. Microscopically, ameloblastomas are recognizable from their recapitulation of embryologic ameloblasts and stellate reticulum. There are 3 subtypes: the conventional or solid-multicystic variant, the unicystic variant, and the desmoplastic variant. Treatment planning for a given tumor includes consideration of location, primary versus recurrent, size, presence of cortical perforation, and age and health of the patient. Complete excision is recommended for conventional and desmoplastic variants. The unicystic variant requires additional subtyping to determine the best treatment approach.

[Primary bone tumors of the orbit]

Primary orbital bone tumors account for 0.6-2% of all orbital tumors. This is a heterogeneous group of tumors arising from osseous, cartilaginous, fibrous, and vascular tissues. The two most commonly encountered lesions are fibrous dysplasia and osteoma. Treatment of the primitive orbital bone tumors is generally surgical.

Effectiveness of a new decisional algorithm in managing mandibular ameloblastomas: A 10-years experience

We present a new treatment algorithm aimed to assist surgeons to develop a rational diagnostic protocol and establish effective conservative surgical management in patients with mandibular ameloblastoma. Fifteen consecutive cases treated by conservative management were reviewed. Data collected included age, sex, symptoms and signs at diagnosis, anatomical distribution of the lesions, numbers and types of operations, number of recurrences, and duration of follow-up post-operatively. Curettage was the first operation for all patients and they were closely followed-up post-operatively. During the follow-up period (4-10 years), small recurrences were diagnosed early in 7 patients who were treated by radical surgery including marginal or "box" resection. No further recurrences were observed after the second operation. When detected early, recurrences are small and surrounded by a large amount of uninvolved normal bone so it is possible to manage them with a radical resection, so lowering the risk of further recurrence and avoiding severe cosmetic and functional problems.

Orbital Invasion by Recurrent Maxillary Ameloblastoma

PURPOSE

To describe 2 patients with orbital invasion by maxillary ameloblastoma, a rare odontogenic tumor that is not commonly encountered in ophthalmic practice.

DESIGN

Retrospective, interventional case report.

METHODS

Two patients who were diagnosed with maxillary ameloblastoma several years ago sought treatment for new-onset ocular and orbital signs and symptoms.

MAIN OUTCOME MEASURES

Clinical and radiological findings and outcome.

RESULTS

In the first patient, tumor recurrence with orbital invasion was diagnosed, and the patient underwent a total orbital exenteration. No recurrence was noted after 18 months of follow-up. The second patient had intracranial involvement with orbital invasion and underwent an extensive resection through an intracranial approach. No recurrence was noted after a 6-month follow-up period.

CONCLUSIONS

Although a slow-growing tumor, maxillary ameloblastoma can recur after surgical excision and can be locally aggressive; it can invade the orbit and result in significant ocular morbidity. Ophthalmologists should be aware of this tumor and should monitor these patients closely when orbital invasion is suspected.

Ameloblastoma in children

PURPOSE

The purpose of this report was 1) to report the experience of the University of Maryland, Department of Oral and Maxillofacial Surgery (OMS Department) in the treatment of ameloblastoma in children and 2) to review the world literature on the treatment of ameloblastoma in children from 1970 to 2001.

METHODS AND MATERIALS

This study first reviews the experience of the OMS Department of the University of Maryland with ameloblastomas in children and then reviews the literature on this subject. The first part of the study was undertaken by a retrospective chart review of all patients with a diagnosis of ameloblastoma in the OMS Department between May 1991 and December 1999. The literature on ameloblastoma in Western societies and Africa was separately reviewed from 1970 through 2001. Reports earlier than 1970 were not reviewed, as the histologic diagnosis of ameloblastoma was not well defined before that period.

RESULTS

In the Maryland series, 11 patients under the age of 20 years with ameloblastoma were treated. Eight patients were seen primarily, and 3 presented with recurrent lesions. The average age was 15.5 years; 5 of 11 patients were black, and 9 of 11 tumors were unicystic ameloblastomas. The literature review showed 85 children in the Western reports and 77 reported from Africa. The average ages were 14.3 and 14.7 years, respectively, but unicystic ameloblastomas accounted for 76.5% of the Western and only 19.5% of the African children, with an increased frequency of occurrence in the mandibular symphisis in African (44.2%) versus Western (5.8%) patients. Analysis of recurrence after enucleation of unicystic ameloblastomas in 20 children followed at least 5 years or until recurrence showed a recurrence of 40%.

CONCLUSIONS

Ameloblastomas in children differ from adults, with a higher percentage of unicystic tumors. African children appear to resemble the adult pattern. Although enucleation has been claimed to give acceptable recurrence rates in unicystic ameloblastoma, there are no large series with long follow-up in children. The histologic pattern that exhibits mural invasion in unicystic ameloblastoma suggests that more aggressive surgery is necessary.

Odontogenic tumors: analysis of 127 cases

One hundred and twenty-seven cases of histologically confirmed odontogenic tumors were retrieved from a total of 5,289 oral and maxillary lesions diagnosed at the Division of Oral Pathology, Federal University of Rio Grande do Norte, during a period of 30 years (1970-1999). The most common histological diagnosis was odontoma (50.40%), followed by ameloblastoma (30.70%). The prevalence of odontogenic tumors was greater in females and the peak incidence occurred in the second and third decades of life. The main anatomical location was the mandible, and no malignant tumors were found.

[Maxillary ameloblastoma: report of two cases]

The ameloblastomas are benign odontogenic tumors locally aggressive that between 15-20% are located in the upper maxillary. The maxillary ameloblastomas have worse forecast than their mandibular homologous upon presenting greater index of postsurgery relapses and a greater percentage of malignancy. Their proximity to nasal cavity, orbit and skull base suppose a risk added by the probability of extension to these structures.

Factors in the pathogenesis of tumors of the sphenoid and maxillary sinuses: a comparative study

OBJECTIVES/HYPOTHESIS

To explain the processes that lead to the development of tumors in the maxillary and sphenoid sinuses.

STUDY DESIGN

A 32-year review of the world's literature on neoplasms of these two sinuses and a randomized case-controlled study comparing the normal mucosal architecture of the maxillary to the sphenoid sinus.

METHODS

Analysis of a 32-year world literature review reporting series of cases of maxillary and sphenoid sinus tumors. Tumors were classified by histological type and separated into subgroups if an individual incidence rate was reported. Histomorphometry of normal maxillary and sphenoid sinus mucosa was performed in 14 randomly selected patients (10 sphenoid and 4 maxillary specimens). Specimens were fixed in 10% formalin, embedded in paraffin, and stained with periodic acid-Schiff (PAS) and hematoxylin. Histomorphometric analysis was performed with a Zeiss Axioscope light microscope (Carl Zeiss Inc., Thornwood, NY) mounted with a Hamamatsu (Hamamatsu Photonics, Tokyo, Japan) color-chilled 3 charge coupled device digital camera. The images were captured on a 17-inch Sony (Sony Corp., Tokyo, Japan) multiscan monitor and analyzed with a Samba 4000 Image Analysis Program (Samba Corp., Los Angeles, CA). Five random areas were selected from strips of epithelium removed from each sinus, and goblet and basal cell measurements were made at magnifications x 100 and x 400.

RESULTS

The literature review revealed that the number and variety of tumors in the maxillary sinus are much greater than those in the sphenoid. The incidence of metastatic lesions to each sinus is approximately equal. No recognized pattern of spread from any particular organ system could be determined. On histomorphometric study there were no statistically significant differences between the sinuses in the concentration of goblet cells, basal cells, or seromucinous glands.

CONCLUSIONS

Factors involved in the pathogenesis of tumors of the maxillary and sphenoid sinuses include differences in nasal physiology, embryology, morphology, and topography. There are no significant histological differences in the epithelium and submucous glands between the two sinuses to explain the dissimilar formation of neoplasms.

Effect of preservation of the inferior and posterior borders on recurrence of ameloblastomas of the mandible

OBJECTIVE

The purpose of this study was to evaluate the experience and results of using a rational radical conservative approach in the surgical treatment of mandibular ameloblastomas.

STUDY DESIGN

A retrospective analysis of every patient with an ameloblastoma of the mandible treated in the Department of Oral Medicine and Oral Surgery at the Jordan University of Science and Technology between 1989 and 1999 was conducted. All were operated on by the author, who used a uniform surgical protocol in every case. All soft tissues in contact or overlying the lesion and a wide margin of cancellous bone related to the tumor were destroyed. The compact bone comprising the lower border of the mandible and the posterior border of the ascending ramus together with the nutrient periosteum attached to them were preserved, thus maintaining the continuity of the mandible and the facial contours. When teeth, soft tissues, or both were involved, they were destroyed. All patients were reviewed annually for a follow-up period of 3 to 10 years (mean, 6.5 years) by the same clinician.

RESULTS

All ameloblastomas were located in the mandible; 21 were in the angle/molar region and the ascending ramus, and 2 cases were in the anterior region. There was no clinical or radiographic evidence of recurrence observed during the follow-up period.

CONCLUSION

Ameloblastoma has a high rate of local recurrence if it is not adequately removed. The findings of this study to date suggest that the technique of rational radical conservative resection may have a place in the treatment of ameloblastoma of the mandible and is worthy of further trial.

Midfacial tumours: a review of 72 cases

We review 72 midfacial tumours managed during the 10-year period between 1985 and 1995. We describe presenting features, sites of lesions and histology, treatment regimens and outcomes, as well as the various surgical approaches for the resection of midfacial tumours, and their indications and contraindications. The choice of approach should be based on type of tumour, its site, and extent.

Diagnostic imaging in two cases of recurrent maxillary ameloblastoma: comparative evaluation of plain radiographs, CT and MR images

We report detailed clinical and imaging findings of two patients with recurrent maxillary ameloblastoma. In one patient the recurrent tumour presented at follow-up examination 5 years after the initial operation. The other patients had a far advanced recurrent tumour with maxillary destruction extending into the adjacent normal structures including the infratemporal fossa, infraorbital fissure, masticator space and the left ethmoid sinus. The findings on conventional radiography including panoramic, posteroanterior and Waters' projection, and the findings of computed tomography (CT) and magnetic resonance (MR) imaging were evaluated using the following three variables: artefact degradation, lesion detectability, and conspicuity. The results suggested that MR imaging was the best imaging method for visualization of the tumours, followed by contrast enhanced CT. These two cases show that maxillary ameloblastoma can be difficult to control when it extends to the adjacent normal structures after destroying the maxilla. MR imaging was essential to establish the exact extent of the advanced maxillary ameloblastoma.