The role of magnetic resonance imaging in the diagnosis and management of ameloblastoma

Nevoid basal cell carcinoma syndrome: a 40-year study in the South African population

BACKGROUND

Nevoid basal cell carcinoma syndrome (NBCCS) is a hereditary autosomal dominant syndrome presenting with a number of signs and symptoms in different population groups.

METHODS

  The investigators implemented a 40-year retrospective analysis of the clinical and radiological features of South Africans affected by NBCCS presenting at the Departments of Oral Surgery, Pathology and Radiology of two major referral hospitals. Details of age, gender, ethnic origin, clinical, and radiological findings were recorded and compared to previous reports. A list of diagnostic criteria for diagnosis of NBCCS in this population was complied. Descriptive statistics were computed, and the P value was set at 0.05 or less.

RESULTS

The sample was composed of 15 patients. The mean age at the time of diagnosis was 22.7years (SD 20.9) with eight (53.3%) patients diagnosed before 20years of age (P=0.0001). The male: female ratio was 2:1. The most frequent major criteria were keratocystic odontogenic tumors (KCOTs) (100%), calcification of falx cerebri (40%), palmo-plantar pits (26.7%), and basal cell carcinomas (BCCs) (20%). The most frequent minor criteria were bifid ribs (20%), skull anomalies (20%), and hypertelorism (20%).

CONCLUSIONS

The results of this study indicate that there was a low frequency of falx cerebri calcifications, BCCs, skull, and rib anomalies in this sample compared to other population groups. These differences could be attributed to genetic, racial, and environmental factors. Future studies are needed to compile diagnostic criteria specific to different population groups.

Imaging features contributing to the diagnosis of ameloblastomas and keratocystic odontogenic tumours: logistic regression analysis

OBJECTIVE

The aim of this study was to clarify the characteristic imaging features that can be used to differentiate ameloblastomas from keratocystic odontogenic tumours and to examine the significant imaging features contributing to a correct diagnosis.

METHODS

60 observers (39 specialists in oral and maxillofacial radiology and 21 non-specialists) examined CT and/or panoramic images of 10 ameloblastomas and 10 keratocystic odontogenic tumours shown on a webpage and made diagnoses. Their correct answer ratios were then calculated. The imaging features of the tumours were evaluated and expressed as binary numbers or quantitative values. The imaging features that contributed to a correct diagnosis were elucidated using logistic regression analysis.

RESULTS

The mean correct answer ratio was 61.3% ± 17.2% for the diagnosis of ameloblastomas and keratocystic odontogenic tumours. CT images produced higher correct answer ratios for diagnosis of keratocystic odontogenic tumours by specialists. The significantly different imaging features between ameloblastomas and keratocystic odontogenic tumours were the degree of bone expansion and the presence of high-density areas. The significant imaging features contributing to a correct imaging diagnosis were the number of locules, the presence of high-density areas and the inclusion of impacted teeth.

CONCLUSION

The presence of high-density areas is the most useful feature in the differential diagnosis of ameloblastomas and keratocystic odontogenic tumours based on comparison of the imaging features of both tumours and examination of the diagnostic contributions of these features.

Dynamic multislice helical CT of ameloblastoma and odontogenic keratocyst: correlation between contrast enhancement and angiogenesis

PURPOSE

The purpose of this study was to assess whether the enhancement characteristics of dynamic multislice helical CT (MS-CT) could help in the differential diagnosis of ameloblastomas and odontogenic keratocysts. The correlation between enhancement characteristics and immunohistochemical findings, especially with regard to angiogenesis, was also evaluated.

METHOD

Dynamic MS-CT was performed in 13 consecutive patients (8 ameloblastoma cases and 5 odontogenic keratocyst cases). The percentage of density increase (Enh%) was measured in dynamic MS-CT images taken during the arterial phase, and microvessel density (MVD) was analyzed using immunohistochemical study with anti-CD31 antibody. The Mann-Whitney U test was used to evaluate the significance of the Enh% or the MVD values between lesion subtypes, and the Spearman correlation coefficient was used to evaluate the correlation between the Enh% and the MVD in ameloblastomas and odontogenic keratocysts.

RESULTS

The Enh% in ameloblastomas was significantly higher than that of odontogenic keratocysts (P < 0.005). The MVD of ameloblastomas was also significantly higher than that of odontogenic keratocysts (P < 0.005). The Enh% values for ameloblastomas and odontogenic keratocysts were positively correlated with the respective MVD values (r = 0.92, P < or = 0.000).

CONCLUSION

Dynamic MS-CT is useful tool for differentiating between ameloblastomas and odontogenic keratocysts on the basis of the contrast enhancement values of intratumoral vascularities during the arterial phase. Furthermore, the Enh% obtained by dynamic MS-CT is correlated with the MVD in ameloblastomas and odontogenic keratocysts.

An approach to the diagnostic imaging of jaw lesions, dental implants, and the temporomandibular joint

This article is an overview of three complex and often confusing areas of diagnostic imaging. It provides the reader with a starting point and a frame of reference from which to proceed when confronted with either an unknown jaw lesion, evaluating a potential dental implant patient, or a patient with TMJ internal derangement.

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.

Three-dimensional computed tomography reconstruction in treatment planning for large ameloblastoma

A case of an unusually large mandibular ameloblastoma is reported in which standard radiologic examination failed to provide adequate visualization of the tumor's limits because of overlapping structures and the presence of compound shadows. Computed tomography imaging and three-dimensional reconstruction proved invaluable in the treatment planning of this large lesion, because it allowed the surgeon to visualize and comprehend the geography of the tumor and its relationship to surrounding structures and soft tissues and to formulate a surgical plan. Use of this technique helped ensure complete excision of the tumor without excessive removal of uninvolved tissue.

Aneurysmal bone cyst versus hemangioma of the mandible. Report of a long-term follow-up of a self-limiting case

The aneurysmal bone cyst is an enigmatic and misnamed lesion displaying variable etiopathogenic and histologic characteristics. The aneurysmal bone cyst may appear as a primary lesion or as a secondary lesion associated with other pathologic entities. This article presents a probable self-limiting lesion that provides an opportunity to present an approach to classifying aneurysmal bone lesions.

Gorlin's syndrome with associated odontogenic cysts

Multiple maxillary and mandibular cysts are principle features of basal cell nevus syndrome (Gorlin-Goltz). We present cases from an affected family in which magnetic resonance imaging (MRI) was helpful in evaluation of the cystic lesions. A middle ear anomaly was identified which may represent an additional abnormality associated with the syndrome.