Detection of bone marrow edema in differential diagnoses of odontogenic cysts using dual-energy computed tomography

PURPOSE

In this study, we prospectively investigated the relationship between bone marrow edema (BME) and odontogenic cysts and explored the possibility of using dual-energy computed tomography (DECT) as an auxiliary tool for the diagnosis of odontogenic cysts.

METHODS

This cross-sectional study included 73 patients who underwent the DECT scan and surgery for odontogenic cysts or odontogenic tumors. The virtual noncalcium (VNCa) computed tomography (CT) values and CT values were measured at several sites. The predictor variable was diagnosis, and the other variables included age, sex, and sites. The primary outcome was VNCa CT value. Variables were tested using the chi-square test or the Kruskal-Wallis test. The VNCa CT and CT values were tested using the Scheffe test for multiple comparisons. All variables were analyzed as independent variables affecting the VNCa CT values around the lesion in the multiple regression analysis.

RESULT

There were 35 men and 38 women. The mean patient age was 50.0 ± 19.5 years (range: 8-86). The VNCa CT values (- 6.2 ± 34.3) around the lesion in patients with RCs were significantly higher than those in patients with dentigerous cysts (- 44.4 ± 28.6) and odontogenic keratocysts (- 67.3 ± 19.5). In multiple regression analysis, the VNCa CT values around the lesion showed a significant positive correlation with histological results (regression coefficient: - 0.605, P < 0.001).

CONCLUSION

The presence of BME is associated with radicular cysts, and DECT can be used as an auxiliary tool for radicular cyst diagnosis.

Radiolucent Jaw Lesions: Imaging Approach

Jaw lesions are a wide array of benign, malignant, and locally aggressive lesions. On radiography, they can appear radiolucent, mixed, or radioopaque. The imaging appearances of radiolucent jaw lesions are markedly overlapping. The role of the radiologist is to formulate a narrow differential diagnosis based on imaging characteristics and aid appropriate management decisions. The aim of this pictorial review is to familiarize the reader with the imaging approach to radiolucent jaw lesions, which form the bulk of jaw lesions in clinical practice.

Overexpression and extra-mitochondrial localization of the chaperonin Hsp60 in ameloblastoma

OBJECTIVES

Ameloblastoma is an odontogenic neoplasm of the mandible and maxilla with various histological types and subtypes. It has been reported that some ameloblastomas could arise from dentigerous cyst walls; thus, the development of ameloblastoma from dentigerous cysts may be due to differential protein expression. Our aim was to identify a membrane protein that is differentially expressed in ameloblastomas with respect to dentigerous cysts.

METHODS

We analyzed the SDS-PAGE profiles of membrane proteins from ameloblastomas and dentigerous cysts. The protein in a band present in the ameloblastoma sample, but apparently absent in the dentigerous cyst sample was identified via mass spectrometry as the chaperonin Hsp60. We used western blotting and immunohistochemistry to analyze its overexpression and localization in ameloblastoma.

RESULTS

We found a differential band of 95 kDa in the membrane proteins of ameloblastoma. In this band, the chaperonin Hsp60 was identified, and its overexpression was corroborated using western blotting and immunohistochemistry. Hsp60 was localized in the plasma membrane of all ameloblastoma samples studied; in addition, it was found in the cell nucleus of the plexiform subtype of conventional ameloblastoma.

CONCLUSIONS

Our results suggest that Hsp60 may be involved in ameloblastoma development, and could therefore be a potential therapeutic target for ameloblastoma treatment.

Evaluation of Radiolucent Lesions Associated with Impacted Teeth: A Retrospective Study

BACKGROUND

Impacted teeth are commonly asymptomatic and not associated with any pathologic lesions for years. Any change in the size of the follicle associated with impacted teeth may result in odontogenic cysts or tumors. CBCT plays an important role in determining the radiographic features of a lesion and therefore, is very helpful for accurate diagnosis and treatment planning.

OBJECTIVE

This study aims to evaluate radiolucent lesions associated with impacted teeth in terms of age and sex distribution, localization, and comparison with the pathological diagnosis.

METHODS

In this retrospective study, out of 6758 CBCT images, 400 images revealing radiolucent lesions were detected. The study included only 190 cases (regarding 180 patients) which had a matching histopathological evaluation. Data related to the age and sex of the patients, localization of the lesions, and their comparison with the pathological diagnosis were recorded and analyzed.

RESULTS

The most encountered lesions were dentigerous cysts (60%) and odontogenic keratocysts (26.3%). Males were the most affected (63.3%). Most of the lesions were found in the left and right posterior mandible and mostly (66.8 %) associated with third molars. Out of 123 radiological diagnoses of dentigerous cyst cases, histopathological diagnoses confirmed 108 cases. Regarding odontogenic keratocyst, histopathological diagnosis confirmed 40 cases out of 48.

CONCLUSION

Radiological diagnoses of the lesions mostly match with their pathological diagnosis unless their characteristics are changed due to infection. CBCT, as a technique enabling detailed imaging of the involved dental structures, is a helpful instrument for differential diagnosis.

Assessment of Hounsfield unit in the differential diagnosis of odontogenic cysts

OBJECTIVES

The purpose of this study was to evaluate the usefulness of Hounsfield unit (HU) assessment with multislice-CT in the differentiation of radicular cysts (RCs), dentigerous cysts (DCs) and odontogenic keratocysts (OKCs).

METHODS

In total, 307 odontogenic cysts (RCs, DCs and OKCs) were included in this study. Cysts with lesion diameter <10 mm, cysts with artefacts affecting measurement of HU values, cysts involving infection and recurrent cysts were regarded as exclusion criteria. Images were acquired in three different types of CT scanners: Aquilion ONE, Discovery CT750 HD and SOMATOM Definition Flash. Differences in HU values among scanners and among types of odontogenic cysts were assessed using one-way analysis of variance; multiple comparisons were performed post hoc, using the Tukey-Kramer honestly significant difference test.

RESULTS

In total, 164 cysts were analysed in this study (64 RCs, 57 DCs and 43 OKCs). Regardless of the type of lesion, the Aquilion ONE scanner demonstrated a significant difference in HU value, compared with the Discovery CT750 HD scanner. Regardless of CT scanner model, HU values significantly differed between DCs and OKCs (p < 0.0001), as well as between OKCs and RCs (p < 0.0001).

CONCLUSIONS

HU values were found to vary among CT scanners and should always be associated with other lesion imaging features while interpreting and elaboration diagnostic hypothesis. Notably, the results suggested that OKCs might be able to be differentiated from DCs and RCs by using HU values.

Ameloblastoma metastásico

El ameloblastoma es un tumor epitelial benigno de origen odontogénico, de crecimiento progresivo, caracterizado por expansión ósea y tendencia a la recurrencia local si no se trata en forma adecuada. De acuerdo con las características clínicas y radiográficas se clasifica en ameloblastoma uniquístico, periférico/extraóseo y el metastásico. En el presente manuscrito se quiere reseñar el caso clínico de un ameloblastoma metastásico, el cual es capaz de producir siembras a pesar de su apariencia histológica benigna. Las variadas formas clínicas y radiográficas hacen que el ameloblastoma metastásico requiera, desde su diagnóstico inicial, un estudio detallado ya que es importante entender el concepto de esta patología como lesión clínica que realiza metástasis a distancia, pero su comportamiento histológico es benigno.

Unusual Imaging Features of Dentigerous Cyst: A Case Report

Dentigerous cysts (DC) are cystic lesions radiographically represented by a well-defined unilocular radiolucent area involving an impacted tooth crown. We present an unusual radiographic feature of dentigerous cyst related to the impacted mandibular right second molar, in a 16-year-old patient, which suggested an ameloblastoma or odontogenic keratocyst (OKC) because of its multilocular appearance seen on the panoramic radiography. A multi-slice computed tomography (MSCT), however, revealed a unilocular lesion without septations, with an attenuation coefficient from 3.9 to 22.9 HU suggesting a cystic lesion. Due to its extension, a marsupialization was performed together with the histopathological analysis of the fragment removed which suggested a dentigerous cyst. Nine months later, the lesion was reduced in size and then totally excised. The impacted mandibular right second molar was also extracted. Histopathological examination confirmed the diagnosis of a dentigerous cyst. One year later, the panoramic radiography showed a complete mandible bone healing. Large dentigerous cysts can sometimes suggest other more aggressive pathologies. Precise diagnosis is important to avoid mistakes since DC, OKC and ameloblastoma require different treatments. Histological examination is, therefore, essential to establish a definitive diagnosis. In our case, MSCT and the tissue attenuation coefficient analysis contributed to guide the diagnosis and management of the dentigerous cyst.

A dinosaurian facial deformity and the first occurrence of ameloblastoma in the fossil record

Despite documentation of various types of neoplastic pathologies encountered in the vertebrate fossil record, no ameloblastic tumours have been recognised so far. Ameloblastoma is a benign neoplasic tumour with a strong preponderance for the mandible. Here, we report for the first time the presence of an ameloblastoma neoplasm in the lower jaw of a specimen referred to the derived non-hadrosaurid hadrosauroid dinosaur Telmatosaurus transsylvanicus from the uppermost Cretaceous of the Haeg Basin in Romania. The location, external appearance and internal structure of the pathological outgrowth provide clear evidence for the diagnosis of ameloblastoma in Telmatosaurus. This report extends the range of pathologies encountered in hadrosauroid dinosaurs. In addition, recognition of an ameloblastoma neoplasm in a taxon lying close to the origin of 'duck-billed' hadrosaurid dinosaurs confirms the predisposition of this clade towards neoplasia pathologies already in its basal members.

Characteristics of bony changes and tooth displacement in the mandibular cystic lesion involving the impacted third molar

OBJECTIVES

The purpose of this retrospective study is to find the differentiating characteristics of cystic and cystic-appearing lesions that involve the impacted mandibular third molar by analyzing panoramic radiographs and computed tomography images, and to aid the preoperative diagnosis.

MATERIALS AND METHODS

Eighty-one patients who had a mandibular cystic or cystic-appearing lesion that involved impacted mandibular third molar and underwent cyst enucleation were included in the study. The preoperative panoramic radiograph and computed tomography findings were analyzed in accordance to the histopathologic type.

RESULTS

Most of the cystic lesions containing the mandibular third molar were diagnosed as a dentigerous cyst (77.8%). The occurrence of mesio-distal displacement of the third molar was more frequent in the odontogenic keratocyst (71.4%) and in the ameloblastoma (85.7%) than in the dentigerous cyst (19.1%). Downward displacement was primarily observed in each group. Odontogenic keratocyst and ameloblastoma showed more aggressive growth pattern with higher rate of bony discontinuity and cortical bone expansion than in dentigerous cyst.

CONCLUSION

When evaluating mandibular cystic lesions involving the impacted mandibular third molar, dentigerous cyst should first be suspected. However, when the third molar displacement and cortical bone absorption are observed, then odontogenic keratocyst or ameloblastoma should be considered.

Ameloblastoma: an aggressive lesion of the mandible

Ameloblastoma is a benign locally invasive epithelial odontogenic tumour comprising 1% of all tumours and cysts arising in the jaws. It is commonly found in the third and fourth decade in the molar ramus region of the mandible. Among all types of ameloblastoma, multicystic ameloblastoma is believed to be locally aggressive lesion that has the tendency for recurrence. In this report we present a large multicystic ameloblastoma in the left body-ramus region of the mandible in a 55-year-old woman. This large lesion was diagnosed with the help of CT and was successfully managed by hemimandibulectomy with simultaneous reconstruction using iliac crest bone.

Histopathologic evaluation of follicular tissues associated with impacted lower third molars

CONTEXT

Previous studies have reported that the dental follicular tissues associated with impacted lower third molars (ILTMs) may undergo cystic degeneration and/or neoplastic transformation. This is especially likely when the pericoronal space is >2.5 mm on intraoral radiographs and >3 mm on panoramic radiographs and to examine dental follicular tissue for pathological changes in patients with ILTMs and pericoronal radiolucencies of <2.5 mm.

AIM

Histopathological evaluation of follicular tissues associated with ILTMs.

MATERIALS AND METHODS

The morphology of the hematoxylin and eosin-stained follicular tissues of 146 such impactions were studied.

RESULTS

On microscopy, no cystic structures with fibrous walls were identified. 85 cases (58%) showed fibrous or myxomatous connective tissue and no epithelial elements. 61 cases (42%) showed epithelial elements in addition to fibrocollagenous tissue. Of these, 16 cases exhibited epithelium, of which 13 cases showed reduced enamel epithelium and three cases showed squamous metaplasia/non-keratinized stratified squamous epithelium.

CONCLUSIONS

All asymptomatic unerupted third molars with pericoronal radiolucency of <2.5 mm should be retained since they do not exhibit cyst formation microscopically.

Achieving adequate margins in ameloblastoma resection: the role for intra-operative specimen imaging. Clinical report and systematic review

Background

Ameloblastoma is a locally aggressive odontogenic neoplasm. With local recurrence rates reaching 90%, only completeness of excision can facilitate cure. Surgical clearance has widely been based on pre-operative imaging to guide operative excision margins, however use of intra-operative specimen x-ray or frozen-section has been sought to improve clearance rates, and advanced imaging technologies in this role have been proposed. This manuscript aims to quantify the evidence for evaluating intra-operative resection margins and present the current standard in this role.

Method

The current study comprises the first reported comparison of imaging modalities for assessing ameloblastoma margins. A case is presented in which margins are assessed with each of clinical assessment based on preoperative imaging, intra-operative specimen x-ray, intra-operative specimen computed tomography (CT) and definitive histology. Each modality is compared quantitatively. These results are compared to the literature through means of systematic review of current evidence.

Results

A comparative study highlights the role for CT imaging over plain radiography. With no other comparative studies and a paucity of high level evidence establishing a role for intra-operative margin assessment in ameloblastoma in the literature, only level 4 evidence supporting the use of frozen section and specimen x-ray, and only one level 4 study assesses intra-operative CT.

Conclusion

The current study suggests that intra-operative specimen CT offers an improvement over existing techniques in this role. While establishing a gold-standard will require higher level comparative studies, the use of intra-operative CT can facilitate accurate single-stage resection.