Ameloblastoma in the Hong Kong Chinese. Part 1: systematic review and clinical presentation

Clinicoradiologic features of ameloblastomas: A single-centre study of 155 cases

BACKGROUND

The purpose of the current study was to report on the clinical presentation and radiologic features of 155 cases of ameloblastoma (AB), representing a detailed, large, single-centre radiologic study.

METHODS

Histologically confirmed cases were reviewed over 11 years. Demographic and clinical data were retrieved from the patient's records. Radiologic information was analysed from available radiographs. The radiologic features of ABs were assessed according to the mean age of presentation and the mean duration of the lesion. The distinguishing radiologic features between adults/children and sex were also evaluated.

RESULTS

A statistically significant correlation existed between loss of border demarcation and advanced mean age. Multilocular lesions were markedly more common in adults compared to children. Multilocular ABs were associated with increased lesion duration and advanced mean age. Radiologic signs of reactive bony changes associated with the tumour presented at the highest mean duration of all bony effects. Bony expansion and cortical destruction were statistically correlated with lesion duration. Tooth impaction was more common in children. Some mandibular lesions reached a significant size, resulting in impingement of the maxillary sinus, zygoma, orbit and pterygoid plates.

CONCLUSION

Due to unfortunate healthcare access constraints, ABs grow to significant sizes and exhibit features not often reported in the literature. The findings of this analysis highlighted the radiologic features of ABs expressed through the mean age and duration of the lesion. This emphasises the significance of timely management of these lesions.

Ameloblastoma of the jaws in adult: A retrospective review of local recurrent lesions based on the resection margin in the adjacent apparent healthy tissues

Background

The surgical treatment of ameloblastoma of the jaws remains contentious due to the variable recurrence rate amongst its variants, the tumor's local invasive behavior, and the lack of consensus among surgeons concerning the extent of resection in the contiguous healthy tissues.

Objective

To determine the recurrence rate of ameloblastoma and its association with the resection margins.

Materials and methods

This is a retrospective cohort study of the medical records of patients who underwent surgical resection of the jaws as the primary modality of treatment for ameloblastoma. Clinical data over the 26 years were analyzed for age, gender, site of the lesion, size, radiographic appearance, histopathological sub-type, and the incidence of recurrence post-treatment. Descriptive and bivariate statistics were computed.

Results

A retrospective audit of 234 cases was included in the study that was typical (solid/multicystic) ameloblastoma. The age of patients ranged from 20 to 66 years with a mean age of 33.4 ± 9.6 years, and a male-to-female ratio of 1.2: 1 (P = 0.52). The follicular and plexiform types accounted for the majority of histopathological variants (89.8%; P = 0.000). Overall, 6.8% of cases relapsed after the initial primary surgery. The rate of recurrence was high with a resection margin of 1.0 or 1.5 cm than 2.0 cm (P = 0.001). No case of recurrence was seen with a resection margin of 2.5 cm margin.

Conclusion

A low recurrence rate of 6.8% was noted in our series of cases. A wide 2.5 cm resection margin is recommended in the adjacent healthy tissues.

Ameloblastoma: An Updated Narrative Review of an Enigmatic Tumor

Ameloblastoma is one of the most common benign odontogenic tumors of the jaw that constitutes about 10% of all tumors that arise in the mandible and maxilla. It is a slow-growing but locally invasive tumor that presents with painless swelling of the mandible or maxilla. The World Health Organization (WHO) classification of 2017 describes ameloblastomas of the following four types: ameloblastoma; unicystic ameloblastoma; extraosseous/peripheral ameloblastoma; and metastasizing ameloblastoma. The diagnosis of ameloblastoma requires computerized tomography (CT) imaging as well as a biopsy. A biopsy is helpful in differentiating ameloblastoma from ossifying fibroma, osteomyelitis, giant cell tumor, cystic fibrous dysplasia, myeloma, and sarcoma. The best treatment of ameloblastoma is aggressive en bloc resection with simultaneous reconstruction. The high recurrence rate and large tissue defects have been long-standing issues in the treatment of ameloblastoma. Recent molecular developments strongly suggest the possibility of targeted therapy with better outcomes in ameloblastomas. We present a detailed updated narrative review of our current understanding and management of this enigmatic tumor.

Keratoameloblastoma: A Report of Seven New Cases and Review of Literature

BACKGROUND

Keratoameloblastoma (KA) is an uncommon and controversial variant of ameloblastoma exhibiting central keratinisation. Due to their rarity, there is limited information in the literature on their clinical, radiologic and histologic features. This study adds seven additional cases of KA to the literature, and reviews the current published literature on this rare entity.

METHODS

KAs were retrospectively reviewed over a 20-year period from three Oral and Maxillofacial Pathology Laboratories. Included cases were examined and the diagnosis confirmed under conventional microscopy. Immunohistochemistry with the use of a monoclonal antibody against calretinin was performed on included cases. The clinical, radiologic and histologic features of the seven new cases of KA were analysed and compared to existing cases in the literature.

RESULTS

KAs presented at a mean age of 40 years with a nearly equal gender distribution and a mandibular predilection (65%). The majority (92%) of cases presented with localised swelling with associated pain in 32% of cases. Mixed density or internal calcifications were noted in 40% of cases. All tumours presented with bony expansion, with cortical destruction noted in 62% of cases. Histologically, all tumours consisted of solid and cystic follicles with surface parakeratinisation and lamellated accumulations of central keratin. In areas the cystic follicles had an epithelial lining suggestive of an OKC. There were focal luminal areas of loosely arranged polygonal cells reminiscent of the stellate reticulum. The basal cells consisted of columnar cells with evidence of palisading and prominent subnuclear vacuolisation. Of the cases treated via tumour resection, 27% presented with tumour recurrence.

CONCLUSION

This case series reports seven additional cases of KA, taking the total to 26 reported cases. The identification of subtle histologic features, including focal stellate reticulum-like central areas, subnuclear vacuolisation and lamellated-type central keratinisation, are key in diagnosing KA. The radiologic features will often indicate signs of aggressiveness such as cortical destruction, differentiating KA from OKC. All cases were completely negative for calretinin IHC, limiting its use in distinguishing KA from OKC. Further large series are needed to expand the current understanding of this rare variant of ameloblastoma.

Controversies in ameloblastoma management: evaluation of decision making, based on a retrospective analysis

BACKGROUND

The ameloblastoma management is still challenging to the high recurrence rates and significant morbidity associated with radical treatment. The purpose of this 10-year retrospective study was to analyze the influence of ameloblastoma type and treatment strategy on the long-term outcomes and recurrence rates.

MATERIAL AND METHODS

The retrospective analyses of 64 histologically-confirmed ameloblastoma cases was performed. The possible risk factors for recurrence and the development of complications were estimated statistically.

RESULTS

The treatment strategy applied for this group of patients was the following: thirty-four patients (53.1%) were treated conservatively with enucleation or extended bone curettage. Radical treatment (bone resection) was applied in 30 (46.9%) cases. The follow-up period ranged from 2 to 10 years (mean value 4.28 ± 3,26). General recurrence rate consisted 32.8%. This study did not find significant correlations between clinical or histopathological features of the ameloblastoma and the recurrence rate. The only factor that significantly influence recurrence rate was the treatment strategy (41% in conservative treatment vs 15% in radical treatment, p<0.05). Postoperative complications were observed in 42 patients (65.6%) and included face asymmetry and disfigurement (17.2%), temporary paresthesia of the inferior alveolar nerve (IAN) - 23.4%, permanent paresthesia of IAN - 20.3%, paresis of a marginal branch of the facial nerve - 6.3%, infection 12.5%, and swelling - 20.3%. The complication rates, esthetic and functional deficiency were significantly higher in radically treated patients (p<0.05) Conclusions: Our study confirms that higher recurrence rate is associated with conservative treatment for ameloblastoma, while radical treatment leads to an increased number of postoperative complications that affect the patient's quality of life.

Study Between Panoramic Radiography and Cone Beam-Computed Tomography in the Diagnosis of Ameloblastoma, Odontogenic Keratocyst, and Dentigerous Cyst

OBJECTIVE

To determine how the diagnosis may or may not be influenced by cone-beam computed tomography (CBCT), comparing the diagnostic hypotheses obtained using images of panoramic radiographs and CBCT in cases of ameloblastoma, odontogenic keratocyst, and dentigerous cyst.

STUDY DESIGN

Five cases were selected for each lesion. Panoramic radiographs and CBCT scans were analyzed by 15 dentists for the formulation of the diagnostic hypotheses. Two observers performed the analyses and measurement of qualitative and quantitative features of the lesions evaluated in the CBCT.

RESULTS

There was no statistically significant difference in correct diagnostic average between panoramic radiography and CBCT, but there was a significant difference in correct diagnostic average in the diagnosis of ameloblastoma using CBCT compared to panoramic radiography. Master's and PhD-level observers had greater correct diagnostic average in the diagnosis of odontogenic keratocyst using panoramic radiograph compared to specialists, with a significant difference.

CONCLUSION

Cone-beam computed tomography images revealed that the ameloblastomas were greater in size and expansion compared to the odontogenic keratocyst and the dentigerous cysts. Ameloblastomas showed a higher incidence of multiloculated aspects compared to odontogenic keratocyst and dentigerous cysts. There were no differences between quantitative and qualitative features of odontogenic keratocyst and dentigerous cysts.

Width-to-length ratio comparison between ameloblastomas and odontogenic keratocysts in the body of the mandible: A preliminary study

Purpose

The purpose of this study was to investigate the utility of the width-to-length ratio for the differentiation of ameloblastomas and odontogenic keratocysts in the body of the mandible.

Materials and Methods

This study retrospectively reviewed 9 patients with ameloblastomas and 9 patients with odontogenic keratocysts using cone-beam computed tomography. The width-to-length ratio was determined by measuring the ratio between the greatest buccolingual dimension and the greatest perpendicular anteroposterior dimension of the lesion on the axial view. One-way analysis of variance was used to examine the difference in the width-to-length ratio between the 2 types of lesions. Statistical significance was tested at P<0.05.

Results

Ameloblastomas showed a mean width-to-length ratio of 0.64, whereas odontogenic keratocysts showed a mean width-to-length ratio of 0.41. The cut-off value with which the 2 types of lesions were differentiated was 0.5. The width-to-length ratios of ameloblastomas were significantly higher than those of odontogenic keratocysts (P<0.05).

Conclusion

The width-to-length ratio might be used to differentiate between ameloblastomas and odontogenic keratocysts.

A Retrospective Study of 158 Cases on the Risk Factors for Recurrence in Ameloblastoma

Background: Ameloblastoma is an odontogenic tumor occurring in jaws, with local aggressiveness and postoperative recurrence. This study was aim to investigate the clinical and radiographic risk factors for recurrence in ameloblastoma. Methods: Patients diagnosed with ameloblastoma between March 2009 and March 2019 were retrospectively analyzed. Clinical and Radiological data and follow-up records were collected. Survival analyses were performed by Kaplan-Meier and log-rank tests, as well as Cox proportional hazards model. Results: One hundred and fifty-eight patients (104 males and 54 females were enrolled. The overall recurrence rate for ameloblastoma was 13.29%, and 10.76% recurred within 5 years. Most of the tumors were located in mandible (86.71%), while the rest 21 cases were in maxilla (13.29%). More than half cases (55.06%) showed multilocular radiolucency, 61 cases (38.61%) showed unilocular radiolucency. Significant differences were found with amelobastoma recurrence rate related to treatment modality, impacted tooth and root resorption (P =0.002, 0.022 and 0.007 respectively). Conclusions: Treatment modality, impacted tooth and root resorption all showed statistically significant associations with the recurrence rate in ameloblastoma. However, due to the limitation of this study, further studies are needed to reveal the true mechanism of ameloblastoma recurrence.

Odontogenic keratocyst and ameloblastoma: radiographic evaluation

OBJECTIVES

To describe the radiographic features of odontogenic keratocysts (OKCs) and ameloblastomas and to compare the radiographic findings between these 2 lesions.

METHODS

Radiographs of OKCs and ameloblastomas were retrospectively reviewed. Location, border, shape, association with impacted tooth, tooth displacement, root resorption, and bone expansion were evaluated. Chi-squared or Fisher's exact tests were used for statistical analysis. A p value < 0.05 was considered to indicate statistical significance.

RESULTS

One hundred OKCs and 101 ameloblastomas were reviewed. The ratios of maxilla to mandible were 1:1.4 and 1:9.1 in OKCs and ameloblastomas, respectively. All evaluated features significantly differed between OKCs and ameloblastomas (p ≤ 0.001). Most OKCs showed smooth border (60%) and unilocular shape (82%), while most ameloblastomas showed scalloped border (77.2%) and multilocular shape (68.3%). Association with impacted tooth was found in 47% of OKCs and 18.8% of ameloblastomas. Adjacent tooth displacement was found in 33.7% of OKCs and 55.8% of ameloblastomas. Root resorption was more common in ameloblastomas (66.7%) than in OKCs (7%). Bone expansion was also more common in ameloblastomas (96.3%) than in OKCs (63.6%).

CONCLUSION

A unilocular radiolucent lesion with smooth border, no adjacent tooth displacement, no root resorption and causing mild or no bone expansion is suggestive of an OKC rather than an ameloblastoma.

Extranodal lymphoma arising within the maxillary alveolus: a systematic review

Objectives

Extranodal lymphomas affecting the head and neck infrequently arise within the jaw bones. Although clinical examination and conventional radiography may initially suffice for such lesions arising within the mandible, those arising within the maxillary alveolus generally require cross-sectional imaging because of the complex anatomy of this region. This study was performed to determine the prevalence, demographic characteristics, and clinical presentations of these lesions and the imaging modalities used for their diagnosis.

Study design

A systematic review (SR) on case series and another SR on case reports were performed to investigate the demographic, clinical, and radiological features of extranodal lymphomas arising within the maxillary alveolus.

Results

Most case series were derived from just four nations, whereas the case reports were derived from a wider range of ethnicities. The more detailed case reports significantly reported at least one imaging modality. Most patients were aware of their lesions for nearly 2 months before presentation. The most frequent symptom was swelling. Most case reports included a provisional diagnosis, the most frequent of which was dental infection followed by squamous cell carcinoma.

Discussion

Extranodal lymphomas arising within the maxillary alveolus were sufficiently frequent in four communities to be reported in two or more case series, and the occasional single case report indicated that such lesions are more widespread globally. Although the SR on case series revealed differences in the relative period prevalence and maxillary/mandibular ratio, the SR on case reports revealed details of the clinical presentation and imaging modalities used.

The Epidemiology, treatment, and complication of ameloblastoma in East-Indonesia: 6 years retrospective study

Background

Ameloblastoma is a neoplasm classified as a benign epithelial odontogenic tumor of the jaws, grow slowly and are locally invasive. The aim of the present study was to investigate the incidence, treatment, and complication of patients with ameloblastoma in East-Indonesia during six years retrospective study.

Material and Methods

This retrospective study included 84 patients who were diagnosed with ameloblastoma from 2011 to 2016. There were 56 patients with treatment data available. Data from each patient, including gender, age, histologic type, the size of the tumor, radiologic form, tumor location, type of treatment, and complication were reviewed and analyzed retrospectively.

Results

Fourteen patients were diagnosed with unicystic ameloblastoma (25%), thirty two patients with multicystic follicular ameloblastoma (57%) and ten patients with an unspecified multicystic ameloblastoma (18%). A total of about 35 patients were treated conservatively (62.5%) and 21 patients were treated radically (37.5%). Swelling was present as a pre-operative complication in all 56 cases (100%). There were no complaints concerning speech.

Conclusions

The majority findings of the histologic type were multicystic ameloblastoma and their location were in the mandible. Most ameloblastoma were treated conservatively and reconstructions were made with only titanium plates and not bone graft.

Key words:Ameloblastoma, epidemiology, east Indonesia.

Trends in maxillofacial imaging

Maxillofacial imaging encompasses radiology of the teeth and jaws, including the temporomandibular joints. Modalities used include intra-oral radiographs, panoramic tomography, cephalograms, cone-beam computed tomography, computed tomography, magnetic resonance imaging, ultrasound, and radionuclide imaging. Common indications for imaging are impacted and supernumerary teeth, dental implants, inflammatory dental disease, and fibro-osseous lesions, cysts, and masses of the jaws. Osteonecrosis of the jaws may follow radiotherapy or the use of bisphosphonates and other drugs. Imaging of the temporomandibular joints and the potential role of imaging in obstructive sleep apnoea are also discussed.

A systematic review of the literature of nevoid basal cell carcinoma syndrome affecting East Asians and North Europeans

OBJECTIVE

To compare, by systematic review, North European and East Asian consecutive case series of nevoid basal cell carcinoma syndrome (NBCCS).

STUDY DESIGN

A systematic review of the literature was performed for all consecutive case series of NBCCS, which included keratocystic odontgenic tumors (KCOTs) arising in North European and East Asian communities. The clinical and radiologically apparent features were identified and synthesized, and a meta-analysis was performed.

RESULTS

East Asian reports were significantly more "proband only" compared with North European reports. Significant differences between these 2 communities were observed for 5 of the 6 major features and 11 of the 27 minor features. With regard to the major NBCCS features, the North Europeans displayed significantly more frequent basal cell carcinomas, calcified falx cerebri, palmar and plantar pits, and a family history, whereas the East Asians displayed KCOTs significantly more frequently. With regard to minor features, East Asians displayed significantly more frequent cleft lips and palates and hypertelorism.

CONCLUSIONS

East Asians displayed multiple KCOTs and cleft lips and palates more frequently compared with North Europeans.

Ameloblastic carcinoma: a case report with radiological features of computed tomography and magnetic resonance imaging and positron emission tomography

Ameloblastic carcinoma is a rare malignant odontogenic carcinoma that has metastatic potential, and because of its rare incidence, there are few reports focusing on its radiologic imaging. If it shows aggressive appearances, it can be diagnosed as malignant tumor. But in case of negative appearance, it is difficult to distinguish ameloblastic carcinoma from ameloblastoma. We report a case of ameloblastic carcinoma of the maxilla in a 76-year-old female patient with radiologic images and pathologic features.

Keratocystic odontogenic tumour: systematic review

OBJECTIVES

The aim of this review is to evaluate the principal clinical and conventional radiographic features of non-syndromic keratocystic odontogenic tumour (KCOT) by systematic review (SR), and to compare the frequencies between four global groups.

METHODS

The databases searched were the PubMed interface of Medline and LILACS. Only those reports of KCOTs that occurred in a series of consecutive cases, in the reporting authors' caseload, were considered.

RESULTS

51 reports, of 49 series of cases, were included in the SR. 11 SR-included series were in languages other than English. KCOTs affected males more frequently and were three times more prevalent in the mandible. Although the mean age at first presentation was 37 years, the largest proportion of cases first presented in the third decade. The main symptom was swelling. Over a third were found incidentally. Nearly two-thirds displayed buccolingual expansion. Over a quarter of cases recurred. Only a quarter of all SR-included reported series of cases included details of at least one radiological feature. The East Asian global group presented significantly as well-defined, even corticated, multilocular radiolucencies with buccolingual expansion. The KCOTs affecting the Western global group significantly displayed an association with unerupted teeth.

CONCLUSIONS

Long-term follow-up of large series that would have revealed detailed radiographic description and long-term outcomes of non-syndromic KCOT was lacking.

Orthokeratinized odontogenic cyst: a systematic review

OBJECTIVES

The aims of the review were to evaluate the principal clinical and conventional radiographic features of orthokeratinized odontogenic cyst (OOC) by systematic review (SR), and to compare the frequency of OOC between four global groups.

METHODS

The databases searched were the PubMed interface of MEDLINE and LILACS. Only those reports of OOCs that occurred in a consecutive series of OOCs in the reporting authors' caseload were considered.

RESULTS

37 reports on 36 case series were included in the SR. OOC affected males twice as frequently and the mandible almost 2.5 times as frequently. Although the mean age at first presentation was 35 years, the largest proportion of cases first presented in the third decade for the Western, East Asian and Latin American global groups. Seven reports included details of at least one clinical finding. 11 reported case series included at least 1 radiological feature. All OOCs were radiolucent, 93% were unilocular and 68% were associated with unerupted teeth. 28% of the reported case series included follow up. 4% of OCC recurred and all of these were in the Western global group.

CONCLUSIONS

Although one feature of OOCs is that they are unlikely to recur, some do. Not only is there a lack of long-term follow up of large series with long-term outcomes of OOC, but there is a paucity of clinical and radiological details of OOC at initial presentation.

Keratocystic odontogenic tumour in a Hong Kong community: the clinical and radiological features

OBJECTIVES

The aim of this study was to evaluate the clinical and conventional radiological features of a consecutive series of cases of "keratocystic odontogenic tumour" (KCOT) affecting a Hong Kong Chinese community and to determine their outcome by follow-up.

METHODS

All cases were accompanied by appropriate radiography and were histopathologically confirmed.

RESULTS

33 consecutive KCOTs were reviewed. 18 patients were male. The mean age at first presentation was 30.6 years. Swelling was the most frequent presenting symptom. Those patients first presenting with pain were significantly older, whereas those first presenting with a maxillary lesion were significantly younger. The maxilla and mandible were affected in 13 and 20 cases, respectively. KCOTs were most frequently confined to the posterior sextants of both jaws. KCOTs affecting the maxilla were mainly unilocular, whereas those affecting the mandible were multilocular. Patients with multilocular KCOTs were significantly older. Patients with KCOTs associated with root resorption were significantly older, whereas patients associated with unerupted teeth were significantly younger. 69% displaced teeth, 41% resorbed them and 56% were associated with unerupted teeth. All but two were followed up for at least 2 years. Three lesions recurred.

CONCLUSIONS

KCOTs in this community displayed some differences from those reported in the literature.

Orthokeratinized odontogenic cyst in a Hong Kong community: the clinical and radiological features

OBJECTIVES

The aim was to evaluate the principal clinical and conventional radiological features of a consecutive series of cases of orthokeratinized odontogenic cyst (OOC) affecting a Hong Kong Chinese community and to determine the outcome by follow-up.

METHODS

All cases were accompanied by appropriate radiography and were confirmed by histopathology.

RESULTS

The clinical and conventional radiological presentations, differential diagnoses and outcomes of follow-up of five consecutive OOCs were reviewed. There were two males and three females. All affected the posterior sextant. The mean age at first presentation was 33.5 years. The mean of their period of prior awareness was 0.11 years. Swelling was the most frequent presenting symptom. All presented as well-defined corticated radiolucencies; three were unilocular and two were multilocular and all displayed expansion. This resulted in displacement and erosion of the lower border of the mandible in one case and the downward displacement past the lower border of a lateral cortex in two others. The inferior dental canal in each mandibular case exhibited both displacement and absence. The antrum was affected in a sole maxillary case. Four patients were followed up for a mean of 8.5 years. The fifth patient discharged himself shortly after surgery. No lesions recurred.

CONCLUSIONS

OOCs in this community displayed an expansile character, but did not recur after moderately long follow-up. The time between the prior awareness of their disease and their presentation for diagnosis and treatment was, so far, the shortest for any lesion affecting the jaw in this Hong Kong Chinese community.

Ossifying fibroma: a systematic review

OBJECTIVES

The aim was to evaluate the principal features of ossifying fibroma (OF) by systematic review (SR), and to compare their frequencies among four global groups.

METHODS

The databases searched were the PubMed interface of MEDLINE and LILACS. Only those reports of OFs that occurred in a series in the reporting authors' caseload were considered. All cases were confirmed fibro-osseous lesions histopathologically. The SR-included series had also to have used radiographs.

RESULTS

Of the 64 reports (including the Hong Kong report) considered, 32 reports and a total of 781 cases were included in the SR. Ten SR-included series were in languages other than English. OF affected females more frequently, but was three times more prevalent in the mandible. The mean age at first presentation was 31 years. The decade with the greatest frequency was the fourth. Females were in the majority except in the first decade. The main symptom in 66% of all SR-included cases was swelling (including deformation of the jaws). 31% were found incidentally. 84% of cases displayed buccolingual expansion; half of the mandibular cases exhibited downward displacement of the lower border of the mandible and 90% of maxillary cases involved the maxillary antrum. Only 28% of reports included follow-up; 12% of cases recurred or were reactivated.

CONCLUSIONS

Although long-term follow-up of large series that would have revealed the long-term outcomes of OF was lacking, a 12% recurrence rate is clinically significant and suggests that OFs should be considered for long-term follow-up.

Fibrous dysplasia: a systematic review

OBJECTIVES

To evaluate the principal features of fibrous dysplasia (FD) by systematic review (SR) and to compare their frequencies between four global groups.

METHODS

The databases searched were the PubMed interface of Medline and LILACS. Only those reports of FD which occurred in a series in the reporting authors' caseload were considered. All cases were confirmed fibro-osseous lesions histopathologically. The SR-included series must also have included radiographs.

RESULTS

Of the 106 reports considered (including the Hong Kong report), 31 reports and a total of 788 cases were included in the SR. 11 SR-included series were in languages other than English. FD affected both genders equally, but was 50% more prevalent in the maxilla. The mean age at first presentation was 24 years. The decade with the greatest frequency was the second, in which males accounted for 63%. The main symptom in 90% of all SR-included cases was swelling (including deformation of the jaws). Not one SR-included case directly involved the ocular apparatus. All cases displayed buccolingual expansion; all mandibular cases exhibited downward displacement of the lower border of the mandible and almost all maxillary cases involved the maxillary antrum. Only 35% of reports included follow-up; 18% of cases recurred or were reactivated. Not one case displayed sarcomatous change.

CONCLUSIONS

Long-term follow-up of large series that would have revealed the long-term outcomes of FD was lacking. This is necessary because many cases do not burn out at the end of adolescence, as expected of a hamartoma, but are reactivated.

Focal cemento-osseous dysplasia: a systematic review

OBJECTIVES

To evaluate the principal features of focal cemento-osseous dysplasia (FocCOD) by systematic review (SR) and to compare their frequencies between four global groups.

METHODS

Alternative names for FocCOD were used as search terms. The databases searched were the PubMed interface of Medline and LILACS (Literature Index for Latin-America and the Caribbean; Biblioteca Regional de Medicina (BIREME)). Only those reports of FocCODs which occurred in a series in the reporting authors' caseload were considered. All cases used radiographs and were confirmed fibro-osseous lesions histopathologically.

RESULTS

Of the 20 series considered, 10 were included in the SR. Five SR-included series were of East Asian communities. 64% of all SR-included cases were found incidentally. FocCOD predominantly affects females and the mandible. The three predominant radiological presentations varied significantly between reports.

CONCLUSIONS

The two at-risk global communities appear to be East Asians and those of black African origin. Although there appears to be little difference between East Asians and non-East Asians, the significant differences between them with regards to the predominant radiological presentation could suggest that either all communities vary in their presentation or that most, if not all, did not reflect the true frequency within their communities. Long-term follow-up of large series that would have revealed the long-term outcomes of FocCODs was lacking. This is necessary because of both FocCOD's predilection of edentulous areas, increasingly required for osseointegrated implants, and its wide differential diagnosis, which includes some lesions normally treated by surgery.

Ameloblastoma in the Hong Kong Chinese. Part 2: systematic review and radiological presentation

OBJECTIVES

The aim of this part of the study was to determine the radiological presentation on conventional radiographs of central ameloblastomas in the Hong Kong Chinese and compare them with other reported series by a systematic review (SR).

METHODS

The study had two elements, that of a complete series of all ameloblastomas presenting at a major Chinese maxillofacial surgical unit and a SR. The files of the Department of Oral and Maxillofacial Surgery of the University of Hong Kong between 1989 and 2000 were reviewed for ameloblastoma cases. The relevant literature was identified by electronic databases, review of citation lists and handsearching of key journals. The principal selection criterion was that the study should represent a complete collection of cases.

RESULTS

Only 13 reports gave any radiological details. The present study of the Hong Kong Chinese contained 61 cases. With the exception of radiodensity and shape of radiolucency, the majority of the 13 other reports did not record the other radiological features that could be important in the diagnosis. The present study agreed with the synthesis of the 13 reports with regards to complete radiolucency and cortication of ameloblastomas, but disagreed with regards to other important features. The present study had a significantly higher proportion of unilocular lesions, better marginal definition, and more frequent perforation of the cortex and buccolingual expansion. Nine of the ten maxillary lesions straddled both anterior and posterior sextants with four crossing the midline, whereas only 13 of the 51 mandibular cases affected both sextants, of which eight crossed the midline. The unicystic form, which was most prevalent, appeared significantly more frequently as unilocular radiolucencies in comparison with the non-unicystic forms. The frequencies of unicystic forms and unilocular presentations were significantly greater in the young. The lesions in the young were significantly sited solely in the posterior sextant. The lower border of the mandible was reached and affected by ameloblastoma in 36 cases in the present report. It was displaced and thinned in 15 cases whereas in just five it was at least partially undisplaced with the lesion expanding down past it either buccally or lingually to it. The unicystic form was significantly more associated with root resorption, tooth displacement and crowns of unerupted teeth.

CONCLUSIONS

Radiologically, ameloblastomas in the Hong Kong Chinese differ significantly with regards to many features. This can be in part explained by the higher proportion of the unicystic form.