Usefulness of contrast enhanced-MRI in the diagnosis of unicystic ameloblastoma

An Unusual Case Report of Unicystic Ameloblastoma of the Mandible

There are plenty of benign lesions that can result in swelling of the mandible, and these can be classified as odontogenic and non-odontogenic lesions. Among the categories of odontogenic lesion, ameloblastoma is the most occurring lesion that takes origin from the epithelial cellular elements and dental tissues in their different stages of development. Ameloblastoma is the most serious odontogenic neoplasm due to its prevalence and clinical characteristics. Ameloblastoma is a broad class which encompasses 80% of solid multicystic type of ameloblastoma with unicystic ameloblastoma (UA) variant included as vital clinicopathological form claiming the rest 20% along with peripheral ameloblastoma variant. UA refers to cystic lesions that seem like jaw cysts clinically, radiographically, or grossly but are lined by typical ameloblastomatous epithelium, with or without luminal and/or mural tumor development, on histologic investigation. Around 5-15% of all ameloblastic lesions do not have a propensity to metastasis, and this is UA. Unicystic mural form, although slow growing overall, is very invasive locally and has a high recurrence rate. As UA tumors show very close features with dentigerous cyst, a very sharp differential diagnosis protocol need to be executed to exclude the other unicystic odontogenic lesions considering the clinical, radiological, and biological characteristics along with proper follow-up and seeing any recurrence of the lesion taking place. Here, we report the case of a twenty-one year male patient with UA of the mandible and review of the literature.

Novel Three-Dimensional and Non-Invasive Diagnostic Approach for Distinction between Odontogenic Keratocysts and Ameloblastomas

Aim of this study was to demonstrate the diagnostic ability to differentiate odontogenic keratocysts (OKCs) from ameloblastomas (AMs) based on computed tomography (CT) or cone beam computed tomography (CBCT) scans. Preoperative CT and CBCT scans from 2004 to 2019 of OKCs and AMs were analyzed in 51 participants. Lesions were three-dimensionally (3D) assessed and Hounsfield units (HU) as well as gray scale values (GSV) were quantified. Calculated HU spectra were compared within the same imaging modalities using unpaired t-tests and correlated with participants characteristics by calculating Pearsons correlation coefficients. Within the CT scans, AMs had highly significantly higher HU values compared to OKCs (43.52 HU and 19.79 HU, respectively; p < 0.0001). Analogous, within the CBCT scans, AMs had significantly higher GSV compared to OKCs (-413.76 HU and -564.76 HU, respectively; p = 0.0376). These findings were independent from participants' gender and age, anatomical site, and lesion size, indicating that the HU- and GSV-based difference reflects an individual configuration of the lesion. HU and GSV spectra calculated from CT and CBCT scans can be used to discriminate between OKCs and AMs. This diagnostic approach represents a faster and non-invasive option for preoperative diagnosis of such entities and has potential to facilitate therapeutic decision making.

Diagnostic efficacy of apparent diffusion coefficient, texture features, and their combination for differential diagnosis of odontogenic cysts and tumors

OBJECTIVE

This study assessed the diagnostic efficacy of apparent diffusion coefficient (ADC), texture features, and their combination for the differential diagnosis of odontogenic cysts and tumors with cyst-like features.

STUDY DESIGN

In total, 14 dentigerous cysts (DCs), 12 odontogenic keratocysts (OKCs), and 6 unicystic ameloblastomas (UABs) were used as predictor variables in 32 outpatients who underwent magnetic resonance imaging. The outcome variables were ADC, texture features, and their combination for each lesion. Texture features including histogram and gray-level co-occurrence matrix (GLCM) were measured on ADC maps. Ten features were selected by using the Fisher coefficient method. The Kruskal-Wallis test and post hoc Mann-Whitney test with Bonferroni adjustment were used to analyze trivariate statistics. Statistical significance was established at P < .05. Receiver operating characteristic analysis was used to evaluate the diagnostic effect of ADC, texture features, and their combination in distinguishing the lesions from each other.

RESULTS

Apparent diffusion coefficient, 1 histogram feature, 9 GLCM features, and their combination demonstrated significant differences between DC, OKC, and UAB (P ≤ .01). Receiver operating characteristic analysis revealed a high area under the curve of .95 to 1.00 for ADC, 10 texture features, and their combination. Sensitivity, specificity, and accuracy ranged from .86 to 1.00.

CONCLUSIONS

Apparent diffusion coefficient and texture features, alone or in combination, can be clinically important in facilitating the distinction between these odontogenic lesions.

The magnetic resonance imaging characteristics of radicular cysts and granulomas

OBJECTIVES

Limited studies have differentiated radicular cysts and granulomas with MRI. Therefore, we investigated the MRI characteristics of the two lesions and clarified features for distinguishing between them.

METHODS

We collected data of 27 radicular cysts and 9 granulomas definitively diagnosed by histopathology and reviewed the fat-saturated T2 weighted, T1 weighted, and contrast-enhanced fat-saturated T1 weighted images. We measured the maximum diameter and apparent diffusion coefficient values of the lesions. We employed Fisher's exact test, the Mann-Whitney U test, and independent t-tests to compare the two lesions and created a decision tree for discriminating between them.

RESULTS

There were significant differences between radicular cysts and granulomas with respect to five imaging characteristics-signal intensity of the lesion centre on fat-saturated T2 weighted images; signal intensity, texture, and contrast enhancement of the lesion centre on contrast-enhanced fat-saturated T1 weighted images; and maximum diameter of the lesion. The cut-off diameter for radicular cysts was 15.9 mm. The area under the receiver operating characteristic curve, sensitivity, and specificity were 0.971, 85.2%, and 100%, respectively.

CONCLUSIONS

From the decision tree analysis, maximum diameter, lesion centre contrast enhancement on contrast-enhanced fat-saturated T1 weighted images, and lesion centre signal intensity on fat-saturated T2 weighted images were important for discriminating between radicular cysts and granulomas.

89Zr-panitumumab PET imaging for preoperative assessment of ameloblastoma in a PDX model

Accurate assessment of tumor margins with specific, non-invasive imaging would result in the preservation of healthy tissue and improve long-term local tumor control, thereby reducing the risk of recurrence. Overexpression of epidermal growth factor receptor (EGFR) has been used in other cancers as an imaging biomarker to identify cancerous tissue. We hypothesize that expression of EGFR in ameloblastomas may be used to specifically visualize tumors. The aims of this study are to measure the specificity of radiolabeled ⁸⁹Zr-panitumumab (an EGFR antibody) in vivo using patient-derived xenograft (PDX) models of ameloblastoma and positron emission tomography/computed tomography (PET/CT) scans. In PDX of ameloblastomas from four patients (AB-36, AB-37, AB-39 AB-53), the biodistribution of ⁸⁹Zr-panitumumab was measured 120 h post-injection and was reported as the injected dose per gram of tissue (%ID/g; AB-36, 40%; AB-37, 62%; AB-39 18%; AB-53, 65%). The radiolabeled %ID/g was significantly greater in tumors of ⁸⁹Zr-panitumumab-treated mice that did not receive unlabeled panitumumab as a blocking control for AB-36, AB-37, and AB-53. Radiolabeled anti-EGFR demonstrates specificity for ameloblastoma PDX tumor xenografts, we believe ⁸⁹Zr-panitumumab is an attractive target for pre-surgical imaging of ameloblastomas. With this technology, we could more accurately assess tumor margins for the surgical removal of ameloblastomas.

Unicystic Ameloblastoma Mimicking Lateral Periodontal Cyst

Intraosseous unicystic ameloblastoma (UA) is a rare subtype of a true neoplasm of odontogenic epithelial origin: ameloblastoma. Despite its rareness, dealing with UA is problematic. It is usually mistaken for an odontogenic cyst, and biopsy is rarely relevant because of its multiple growth patterns. The biggest challenge remains the treatment choice. When we are faced with a mural UA presenting strong similarities with a lateral periodontal cyst and having high rates of recurrence, how is the balance found between the young age, psychological fragility, postoperative process, and need for diagnostic biopsy? That was our dilemma. Our patient is a 23-year-old man with a mural unicystic ameloblastoma, diagnosed with general anxiety disorder. The final decision was to turn to a simple enucleation because of the small size of the lesion, and its radiological features strongly evoked a lateral periodontal cyst. Besides, his young age, psychological condition, and UA's proximity to the surrounding soft tissues guided us toward simple enucleation. Two years later, no sign of radiological recurrence was noted. However, we are aware of a later possibility of resection in case of recurrence.

Usefulness of MR imaging for odontogenic tumors

MRI has become an invaluable diagnostic tool in all areas of the body. However, it has not been widely used to image odontogenic tumors of the jaw. Major advantages of MRI include excellent soft tissue contrast in the absence of ionizing radiation. Furthermore, diffusion-weighted MRI and dynamic contrast-enhanced MRI can be used as functional imaging techniques for assessing tissue biology. In this review article, we present representative MR images of several types of odontogenic tumors, and discuss MR imaging characteristics useful for differential diagnosis.

Three-dimensional radiographic features of ameloblastoma and cystic lesions in the maxilla

OBJECTIVES

To characterize the radiographic features of maxillary ameloblastoma (AM), odontogenic keratocyst (OKC) and dentigerous cyst (DC) comparatively by using spiral CT and cone beam CT (CBCT).

METHODS

Clinical records, histopathological reports, and nonenhanced spiral CT or CBCT images of 191 consecutive patients with primary maxillary AMs, OKCs, or DCs were retrospectively acquired, and radiographic features were analyzed.

RESULTS

The study included 118 males and 73 females (age: 5-84 years). 72.0% of AMs and 84.3% of OKCs originated from the posterior maxilla, while 69.6% of DCs occurred in the anterior maxilla. Among 25 AMs, 44.0% were of desmoplastic type, with honey-combed appearance. 84.0% of AMs were circular or oval in shape, 84.0% expanded buccally, and 36.0% invade the nasal floor. Among 89 OKCs of 88 patients, 61.8% were circular or oval, 58.4% expanded buccally, 49.4% were dentigerous, 41.6% nearly filled the maxillary sinus, and 13.5% invaded the nasal floor. 93.7% (74/79) of DCs enveloped a single tooth, and the tooth-cyst relationship was centripetal in 35, eccentric in 30, and circumferential in 9. Moreover, 98.2% (55/56) of the cysts enveloping a supernumerary tooth were DCs, while 80.9% (38/47) of the cysts enveloping the third molar were OKCs.

CONCLUSIONS

Maxillary AMs tend to grow with buccal expansion and invade the nasal floor, and DAs with honey-combed lobularity are common. Maxillary OKCs have variant shapes and tend to invaginate the maxillary sinus. The tooth-cyst relationship of dentigerous OKCs and DCs can be centripetal, eccentric, or circumferential.

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.

Odontogenic keratocyst: imaging features of a benign lesion with an aggressive behaviour

Abstract

The latest (4th) edition of the World Health Organization (WHO) Classification of Head and Neck Tumours, published in January 2017, has reclassified keratocystic odontogenic tumour as odontogenic keratocyst. Therefore, odontogenic keratocysts (OKCs) are now considered benign cysts of odontogenic origin that account for about 10% of all odontogenic cysts. OKCs arise from the dental lamina and are characterised by a cystic space containing desquamated keratin with a uniform lining of parakeratinised squamous epithelium. The reported age distribution of OKCs is considerably wide, with a peak of incidence in the third decade of life and a slight male predominance. OKCs originate in tooth-bearing regions and the mandible is more often affected than the maxilla. In the mandible, the most common location is the posterior sextant, the angle or the ramus. Conversely, the anterior sextant and the third molar region are the most common sites of origin in the maxilla. OKCs are characterised by an aggressive behaviour with a relatively high recurrence rate, particularly when OKCs are associated with syndromes. Multiple OKCs are typically associated with the nevoid basal cell carcinoma syndrome (NBCCS), an autosomal dominant multisystemic disease. Radiological imaging, mainly computed tomography (CT) and, in selected cases, magnetic resonance imaging (MRI), plays an important role in the diagnosis and management of OKCs. Therefore, the main purpose of this pictorial review is to present the imaging appearance of OKCs underlining the specific findings of different imaging modalities and to provide key radiologic features helping the differential diagnoses from other cystic and neoplastic lesions of odontogenic origin.

Key Points

• Panoramic radiography is helpful in the preliminary assessment of OKCs.

• CT is considered the tool of choice in the evaluation of OKCs.

• MRI with DWI or DKI can help differentiate OKCs from other odontogenic lesions.

• Ameloblastoma, dentigerous and radicular cysts should be considered in the differential diagnosis.

• The presence of multiple OKCs is one of the major criteria for the diagnosis of NBCCS.

Differential diagnosis between a granuloma and radicular cyst: effectiveness of magnetic resonance imaging

AIM

To investigate the diagnostic reliability and accuracy of magnetic resonance imaging (MRI) to differentiate periapical lesions of endodontic origin and to compare the results with histopathological information.

METHODOLOGY

The radiolucent periapical jaw lesions of 34 patients, which were surgically enucleated, were investigated by two radiologists using MRI, based on the same six criteria, to categorize the lesions as granulomas, radicular cysts or others. After apicoectomies, two oral pathologists (blinded to the radiologist's diagnoses) analysed all specimens by referring to seven specific parameters and diagnosed the specimens as granulomas, radicular cysts or other conditions. The inter-rater agreements between the radiologists and pathologists in terms of MRI and histological diagnoses, respectively, along with the discriminant power of the adopted criteria and the accuracy of the MRI assessments compared with the histopathological results, were calculated. Cohen's kappa test was adopted to examine inter-rater agreement between the two radiologists and two pathologists. Guttman's lambda coefficient (λ₆ ) was used to evaluate the internal consistency of the items used for the differential diagnosis by radiologists. The accuracy resulted from a receiver operator characteristic (ROC) analysis.

RESULTS

A strong inter-rater reliability was observed between the two radiologists (k-statistic = 0.86, P = 0.0001) and the two pathologists (k-statistic = 0.88, P = 0.0001). The internal consistency of the diagnostic items was 0.605 for cysts and 0.771 for granulomas. The accuracy (true positives plus true negatives) of the radiologists was greater than that of the pathologists based on analysis (area under the curve = 0.87 and 0.91, respectively).

CONCLUSIONS

The reliability and accuracy of MRI were high and comparable to histopathological reliability, highlighting the usefulness of this noninvasive technique as a pre-treatment diagnostic method for periapical endodontic lesions.

Diffusion-Weighted MR Imaging of Unicystic Odontogenic Tumors for Differentiation of Unicystic Ameloblastomas from Keratocystic Odontogenic Tumors

Objective

Differentiating unicystic ameloblastomas from keratocystic odontogenic tumors (KCOT) is necessary for the planning of different treatment strategies; however, it is difficult based on conventional CT and MR sequences alone. The purpose of this study was to investigate the utility of diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADCs) in the differentiation of the two tumors.

Materials and Methods

We prospectively studied 40 patients with odontogenic cysts and tumors of the maxillomandibular region using conventional MR imaging and DWI. ADCs were measured using 2 b factors (500 and 1000).

Results

Unicystic ameloblastomas (n = 11) showed free diffusion on DWI and a mean ADC value of 2.309 ± 0.17 × 10^-3 mm²/s. KCOT (n = 15) showed restricted diffusion on DWI with a mean ADC value of 0.923 ± 0.20 × 10^-3 mm²/s. The ADC values of unicystic ameloblastomas were significantly higher than those of KCOT (p < 0.001, Mann-Whitney U-test). An ADC cut-off value of 2.0 × 10^-3 mm²/s to differentiate KCOT and unicystic ameloblastomas resulted in a 100% sensitivity and 100% specificity. Dentigerous cysts (n = 3) showed restricted diffusion on DWI and similar ADC values (1.257 ± 0.05 × 10^-3 mm²/s) to those of KCOT.

Conclusion

Diffusion-weighted imaging and ADC determination can be used as an adjuvant tool to differentiate between unicystic ameloblastomas and KCOT, although the ADC values of dentigerous cysts overlap with those of KCOT.

Focal Benign Disorders of the Pediatric Mandible With Radiologic-Histopathologic Correlation: Mandibular Development and Lucent Lesions

OBJECTIVE

Lucent lesions of the pediatric mandible may present variably. Cysts, neoplasms, and developmental and inflammatory conditions have a host of possible causes. There is also substantial overlap in the imaging appearance of cysts and that of benign but locally aggressive tumors that need to undergo resection.

CONCLUSION

The purpose of this article is to present common and uncommon lucent lesions of the mandible in children, with an emphasis on benign abnormalities. Discussions of imaging and histopathologic features are provided.

Contrast-enhanced multidetector computerized tomography for odontogenic cysts and cystic-appearing tumors of the jaws: is it useful?

OBJECTIVE

The purpose of this study was to investigate the usefulness of computerized tomography (CT), particularly contrast-enhanced CT, in differentiation of jaw cysts and cystic-appearing tumors.

STUDY DESIGN

We retrospectively analyzed contrast-enhanced CT images of 90 patients with odontogenic jaw cysts or cystic-appearing tumors. The lesion size and CT values were measured and the short axis to long axis (S/L) ratio, contrast enhancement (CE) ratio, and standard deviation ratio were calculated.

RESULTS

The lesion size and the S/L ratio of keratocystic odontogenic tumors were significantly different from those of radicular cysts and follicular cysts. There were no significant differences in the CE ratio among the lesions.

CONCLUSIONS

Multidetector CT provided diagnostic information about the size of odontogenic cysts and cystic-appearing tumors of the jaws that was related to the lesion type, but showed no relation between CE ratio and the type of these lesions.

Unicystic mural ameloblastoma: an unusual case report

Ameloblastoma is a benign odontogenic neoplasm which frequently affects the mandible. The term ameloblastoma includes several clinicoradiological and histological types. Apart from the most commonly encountered clinicopathologic models, there are few variants, whose biological profile is unknown or not elicited. Among these types, unicystic ameloblastoma is the least encountered variant of the ameloblastoma. Unicystic ameloblastoma refers to those cystic lesions that show clinical, radiographic, or gross features of a jaw cyst but on histologic examination show a typical ameloblastomatous epithelium lining the cyst cavity, with or without luminal and/or mural tumor proliferation. Unicystic ameloblastoma is a less encountered variant of the ameloblastoma and is believed to be less aggressive. As this tumor shows considerable similarities with dentigerous cysts, both clinically and radiographically, the biologic behaviour of this tumor group was reviewed. Moreover, recurrence of unicystic ameloblastoma may be long delayed, and a long-term postoperative followup is essential for proper management of these patients. Here we are presenting a case of unicystic ameloblastoma in an 18-year-old female patient.

Diagnostic value of MRI for odontogenic tumours

OBJECTIVES

To evaluate the diagnostic value of MRI for odontogenic tumours.

MATERIALS AND METHODS

51 patients with odontogenic tumours were subjected to pre-operative MRI examinations. For tumours with liquid components, i.e. ameloblastomas and keratocystic odontogenic tumours (KCOTs), the signal intensity (SI) uniformity of their cystic components (UΣ) was calculated and then their UΣ values were compared. For tumours with solid components that had been examined using dynamic contrast-enhanced MRI (DCE-MRI), their CImax (maximum contrast index), Tmax (the time when CImax occurred), CIpeak (CImax × 0.90), Tpeak (the time when CIpeak occurred) and CI300 (i.e. the CI observed at 300 s after contrast medium injection) values were determined from CI curves. We then classified the odontogenic tumours according to their DCE-MRI parameters.

RESULTS

Significant differences between the UΣ values of the ameloblastomas and KCOT were observed on T1 weighted images, T2 weighted images and short TI inversion recovery images. Depending on their DCE-MRI parameters, we classified the odontogenic tumours into the following five types: Type A, CIpeak > 2.0 and Tpeak < 200 s; Type B, CIpeak < 2.0 and Tpeak < 200 s; Type C, CI300 > 2.0 and Tmax < 600 s; Type D, CI300 > 2.0 and Tmax > 600 s; Type E, CI300 < 2.0 and Tmax > 600 s.

CONCLUSION

Cystic component SI uniformity was found to be useful for differentiating between ameloblastomas and KCOT. However, the DCE-MRI parameters of odontogenic tumours, except for odontogenic fibromas and odontogenic myxomas, contributed little to their differential diagnosis.

Maxillary unicystic ameloblastoma: A review of the literature

The term unicystic ameloblastoma (UA) refers to those cystic lesions that show clinical, radiographic, or gross features of a jaw cyst, but on histologic examination show a typical ameloblastomatous epithelium lining part of the cyst cavity, with or without luminal and/or mural tumor growth. Although the histology suggests that cystic ameloblastomas follow a biologically low-grade course, recent evidence suggests that they may often behave clinically as aggressive tumors. This is supported by the high incidence of cortical perforation, tooth resorption, increase in lesion size, bony destruction, and a high rate of recurrence after simple enucleation. Here, the authors present a case report on unicystic variant of ameloblastoma in the maxilla. An attempt has been made to emphasize that it can involve the maxillary jaw, which is rarely affected and could be more aggressive than previously thought. A literature review on the topic has been added along with the case report. It is important to remember that a proper and timely diagnosis of the character and extent of a UA (with a thorough histopathologic examination of the entire specimen) can help in the overall long-term well-being of the patient.

Five years follow-up of implant-prosthetic rehabilitation on a patient after mandibular ameloblastoma removal and ridge reconstruction by fibula graft and bone distraction

This case report presents a combination of surgical and prosthetic solutions applied to a case of oral implant rehabilitation in post-oncologic reconstructed mandible. Bone resection due to surgical treatment of large mandibular neoplasm can cause long-span defects. Currently, mandibular fibula free flap graft is widely considered as a reliable technique for restoring this kind of defect. It restores the continuity of removed segment and re-establishes the contour of the lower jaw. However, the limited height of grafted fibula does not allow the insertion of regular length implants, therefore favouring vertical distraction osteogenesis as an important treatment choice. This report presents a patient affected by extensive mandibular ameloblastoma who underwent surgical reconstruction by fibula free flap because of partial mandibular resection. Guided distraction osteoneogenesis technique was applied to grafted bone, in order to obtain adequate bone height and to realize a prosthetically guided placement of 8 fixtures. After osseointegration, the patient was rehabilitated with a full arch, screw-retained prosthetic restoration. At five-years follow up, excellent integration of grafted tissue, steady levels of bone around the fixtures and healthy peri-implant tissues were reported.

Usefulness of MRI and dynamic contrast-enhanced MRI for differential diagnosis of simple bone cysts from true cysts in the jaw

INTRODUCTION

It can be difficult to differentiate simple bone cysts (SBCs) from true cysts in the jaw when these lesions appear unilocular. The present study reports the MR imaging of subjects with SBCs and describes the diagnostic value of the MRI findings.

MATERIALS AND METHODS

Ten subjects with SBCs in the jaw were examined using MRI. T1- and T2-weighted images (T1WI, T2WI) were obtained, and contrast-enhanced images and dynamic contrast-enhanced MRI (DCE-MRI) were acquired.

RESULTS

In all cases, the contrast-enhanced T1WI acquired approximately 6 minutes after the administration of Gd-DTPA showed marked enhancement of the margin and slight enhancement of the inner part of the cyst cavity. In all cases, the time-signal intensity (SI) curves show a gradual increase in the SI until approximately 15 minutes after the administration of Gd-DTPA. These findings might not be observed on the DCE-MRIs of the other true cysts with epithelial lining that show no enhancement in a cavity.

CONCLUSION

MRI, especially DCE-MRI, can provide useful information for distinguishing SBCs from other cysts.

Unicystic ameloblastoma of the mandible--an unusual case report and review of literature

Ameloblastoma is a true neoplasm of odontogenic epithelial origin. It is the second most common odontogenic neoplasm, and only odontoma outnumbers it in reported frequency of occurrence. Its incidence, combined with its clinical behavior, makes ameloblastoma the most significant odontogenic neoplasm. Unicystic ameloblastoma (UA) refers to those cystic lesions that show clinical, radiographic, or gross features of a mandibular cyst, but on histologic examination show a typical ameloblastomatous epithelium lining part of the cyst cavity, with or without luminal and/or mural tumor growth. It accounts for 5-15% of all intraosseous ameloblastomas. We report a case of unicystic ameloblastoma in a 30-year-old female, and review the literature.

[Imaging of odontogenic tumors of the maxilla]

Odontogenic tumors of the maxilla are frequent, mainly represented by cysts of the jaw. However, this group of tumors include a large number of potentially intricate pathologies whose evolution is dominated by frequent recurrences justifying long-term follow-up. When such a lesion is discovered, evaluation of imaging features combined with an extensive knowledge of the different patterns of other lesions (particularly their potentially evolutive patterns related to growth) can often suggest the diagnosis. While definitive diagnosis frequently relies on histology, it is not rare that the patterns are so intricate that final diagnosis is based on a correlation between clinical, imaging and histological findings.