Dentigerous Cyst and Ameloblastoma of the Jaws

Expression of Calretinin Expression in Odontogenic Cysts and Odontogenic Tumors - Original Research

Aim

The present study was conducted for assessing variability in calretinin expression among odontogenic cysts as well as tumor cases.

Materials and Methods

Fifteen cases were included in the present research consisting of cases like - dentigerous cyst, odontogenic keratocyst, apical radicular cyst along with tumors like ameloblastoma, ameloblastic carcinoma, adenomatoid odontogenic tumor. Calretinin antibody was used for immunohistochemical staining. The amount of expression of this calretinin was statistically analyzed with the help of Chi-square test where P < 0.05 was considered noteworthy statistically.

Results

Most cases of ameloblastomas were highly positive for calretinin expression as compared to other cysts and tumors. Therefore, the correlation of this variation of expression of calretinin was statistically noteworthy (P = 0.00).

Conclusion

In this study, we concluded that for ameloblastomas, calretinin can be a specific marker immunohistochemically and can help in identifying the amount of aggressive spread of various odontogenic tumors.

Differential expression of PEA3 in odontogenic cysts and tumors

BACKGROUND

PEA3 transcription factor has been identified as a downstream target of the MAPK and PI3K pathways, and PEA3 overexpression has been observed in a variety of tumor types. We aimed to evaluate PEA3 expression in odontogenic cysts and tumors and compare the expression among odontogenic lesions. In addition, the correlations between PEA3 expression and clinicopathological characteristics of conventional ameloblastoma and unicystic ameloblastoma were investigated.

METHODS

This study was performed on 165 samples of odontogenic cysts and tumors including 20 dentigerous cysts, 20 odontogenic keratocysts, 16 adenomatoid odontogenic tumors, 5 ameloblastic fibromas, 45 unicystic ameloblastomas, and 59 conventional ameloblastomas. The sections were immunohistochemically stained with mouse monoclonal anti-PEA3 antibody and PEA3 expression was evaluated as the immunoreactive score.

RESULTS

PEA3 expression was absent in all dentigerous cysts (DCs) and odontogenic keratocysts, while all adenomatoid odontogenic tumors showed either no (75%) or low (25%) expression of PEA3. Most of the ameloblastic fibromas (60%) displayed no PEA3 expression. A high expression of PEA3 was observed in a substantial number of unicystic ameloblastomas (48.9%) and conventional ameloblastomas (49.2%) in our study. PEA3 expression in DCs, odontogenic keratocysts and adenomatoid odontogenic tumors were significantly different from that in conventional ameloblastomas and that in unicystic ameloblastomas (p < 0.05). The expression of PEA3 was significantly different in the age groups of unicystic ameloblastomas and histological subtypes of conventional ameloblastomas (p < 0.05).

CONCLUSION

PEA3 overexpression is predominant in unicystic ameloblastomas and conventional ameloblastomas compared to other odontogenic lesions, indicating a pivotal role of PEA3 as a downstream effector of MAPK pathway in these two odontogenic lesions.

Primary cilia and hypoxia-associated signaling in developmental odontogenic cysts in relation to autosomal dominant polycystic kidney disease - A novel insight

Developmental cysts are pathological epithelial-lined cavities arising in various organs as a result of systemic or hereditary diseases. Molecular mechanisms involved in the formation of developmental odontogenic cysts (OCs) are not fully understood yet; the cystogenesis of renal cysts originating from the autosomal dominant polycystic kidney disease (ADPKD) has been, however, explored in much greater detail. This narrative review aimed i) to summarize molecular and cellular processes involved in the formation and growth of developmental OCs, especially dentigerous cysts (DCs) and odontogenic keratocysts (OKCs), ii) to find if there are any similarities in their cystogenesis to ADPKD cysts, and, based on that, iii) to suggest potential factors, candidate molecules, and mechanisms that could be involved in the DC formation, thus proposing further research directions. Here we suggest a possible association of developmental OCs with primary cilia disruption and with hypoxia, which have been previously linked with cyst formation in ADPKD patients. This is illustrated on the imagery of tissues from an ADPKD patient (renal cyst) and from developmental OCs, supporting the similarities in cell proliferation, apoptosis, and primary cilia distribution in DC/OKC/ADPKD tissues. Based on all that, we propose a novel hypothesis of OCs formation suggesting a crucial role of mutations associated with the signaling pathways of primary cilia (in particular, Sonic Hedgehog). These can lead to excessive proliferation and formation of cell agglomerates, which is followed by hypoxia-driven apoptosis in the centers of such agglomerates (controlled by molecules such as Hypoxia-inducible factor-1 alpha), leading to cavity formation and, finally, the OCs development. Based on this, we propose future perspectives in the investigation of OC pathogenesis.

Dentigerous cyst and the importance of early detection. report of a pediatric case

Dentigerous cysts are a common cystic pathology that develop between the first and third decade of life and are mainly associated with impacted or erupted mandibular third molars followed by maxillary canines and maxillary third molars. These kinds of cysts are the result of the proliferation of enamel epithelium after its formation, the pathogenesis of which is not clear. Few of these cysts have been reported in pediatric patients. The following case report presents the rare occurrence of a dentigerous cyst in a 6-year-old boy and describes the treatment administered.

[Use of current imaging tools for the study of odontogenic myxoma. A review of the literature]

Odontogenic myxoma (OM) is currently classified as a benign tumor of ectomesenchymal origin, observed between the second and fourth decade of age, with a predilection in women and predominance in the mandibular region, composed of rounded and angular cells embedded in an abundant myxoid stroma, of aggressive biological behavior, having the characteristic of being locally infiltrative. Tumor cells spread in the intratrabecular space beyond the bone limit, making it difficult to determine the edge of the tumor, even without cortical continuity, presenting intermittent direct contact with soft tissue; the appearance can be unilocular (small lesions), or commonly the typical image is that of a destructive lesion with poorly defined borders with a multilocular growth pattern, for which the use of advanced medical images such as Cone Beam Computed Tomography (CTHC), Computed Tomography (CT), Magnetic Resonance Imaging (MRI), are useful to establish an adequate diagnosis with the ability to point out the characteristics of OM with precision and three-dimensional perspective. This review presents a systematic analysis of the types of imaging tools currently used for the study of OM.

Differentiation of cystic lesions in the jaw by conventional magnetic resonance imaging and diffusion-weighted imaging

OBJECTIVES

This study aimed to determine the discrimination power of apparent diffusion coefficient (ADC) for cystic lesions in the jaw using MRI.

METHODS

We selected 127 cystic lesions, comprising dentigerous cysts (DCs), odontogenic keratocysts (OKCs), and unicystic ameloblastomas (UABs), from our MRI database examined by 3T MRI, including diffusion-weighted imaging sequences, and we reviewed their imaging characteristics. We attempted to discriminate the three types of lesions by ADC values with receiver operator characteristic analysis; however, satisfactory results were not obtained for differentiation between DC and OKC. Therefore, we performed a decision tree analysis.

RESULTS

The imaging characteristics of the lesions were significantly different according to Fisher's exact test, except for differences in sex. The ADC values statistically discriminated the lesions of DC and UAB, OKC and UAB, but not DC and OKC. Thus, differentiation was performed by a decision tree for DC and OKC by evaluating the following points: the attached tooth condition, signal intensity on the T₁ weighted image (T₁SI), ADC value, and the cyst site. However, cases showing hypo- or isointense T₁SI with an ADC value under 1.168 × 10^-3 mm²/s were difficult to differentiate.

CONCLUSION

The ADC value helped distinguish UAB from both DC and OKC, but not DC from OKC. However, the decision tree based on ADC value, tooth contact status, and T₁SI helped differentiate DC and OKC to some extent.

Proliferative and anti-apoptotic indices of unicystic ameloblastoma, odontogenic keratocyst, dentigerous cyst and radicular cyst

Objective:

The aim of this study is to compare the proliferative capacity and antiapoptotic capacity of unicystic ameloblastoma (UA), odontogenic keratocyst (OKC), dentigerous cyst (DC) and radicular cyst (RC) by assessing the Ki-67 labeling index (LI) and Bcl-2 LI, respectively.

Materials and Methods:

Formalin-fixed, paraffin-embedded tissue blocks of twenty-three histopathologically diagnosed UAs, 6 OKCs, 8 DCs and 10 RCs were selected from the archival specimens. Five micrometer thick sections of tissue blocks of the lesions were processed for immunohistochemical staining with Ki-67 and Bcl-2. The Ki-67 LI and Bcl-2 LI were determined for the cases with a positive reaction.

Results:

Ki-67 expression was seen in 6 (26.1%) cases of UA, 4 (66.7%) OKC, 1 (12.5%) DC and 1 (10.0%) RC. There was a statistically significant difference between the mean Ki-67 LI of UA and OKC (P = 0.024). Bcl-2 expression was seen in 16 (69.6%) UA, 5 (83.3%) OKC, 5 (62.5%) DC and 5 (50.0%) RC. The mean Bcl-2 LI of UA was significantly higher than that of DC (P = 0.048). Furthermore, cases of OKC had significantly higher mean Bcl-2 LI compared to DC (P = 0.026) and RC (P = 0.049).

Conclusion:

This study suggests that the Ki-67 LI may help in differentiating OKC from UA. The Bcl-2 LI may be useful in differentiating UA from DCs, and differentiating OKC from DC and RC.

Surgical Strategies for Multicystic Ameloblastoma

Ameloblastoma is the second most common odontogenic tumor arising in the maxillary bones. The WHO classified ameloblastoma in: solid/multicystic (SMA); unicystic; peripheral and desmoplastic. A conservative or radical approach may be performed for SMA treatment to achieve total excision of the lesion.In this case report, a 47-year-old woman, presented a deformation of the left mandibular region and paresthesia of the left hemi-labium, at the ortopanoramic x-ray (OPT) a multilocular osteolytic lesion and the rhizalysis of dental elements 3.7, 3.6, 3.5, 3.4 and the inclusion of 3.8 was appreciated; the CT exam showed erosion of the mandibular canal roof and of the vestibular cortex in the mental nerve region. The patient was subjected to the extraction of the elements in rhizalysis and of 3.8 and subsequently to the enucleation of the lesion followed by an extensive peripheral ostectomy performed with a piezoelectric device. The patient underwent to OPT and CT examinations follow-up and after 5 years was subjected to implant surgery, at the same time of the implant's placement, bone biopsies were performed using core drills in order to evaluate the bone histologically. The patient showed complete clinical and radiographic healing; the histological examination demonstrates the formation of lamellar bone.

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.

Global incidence and profile of ameloblastoma: A systematic review and meta-analysis

OBJECTIVES

To evaluate the global incidence of ameloblastoma and to provide a profile of ameloblastoma patients.

MATERIAL AND METHODS

A systematic review and meta-analysis was conducted. Searches were performed in PubMed, EMBASE, SCOPUS, and Web of Science for articles published from 1969 to 2018 for the global incidence and from 1995 to 2018 for the profile of ameloblastoma patients.

RESULTS

Seven studies on the incidence rate of ameloblastoma were included in the meta-analysis. These studies only covered Europe, Africa, and Australia. The pooled incidence rate was 0.92 per million person-years (95% CI: 0.57-1.49), with significant heterogeneity between studies. Forty-two articles provided profile data of 6,446 ameloblastoma patients. Mean age was 34 years and the peak age incidence in the third decade of life. In Europe and North America, ameloblastoma mostly occurred at an older age when compared to Africa and South America. A slight male preference (53%) was found, and the mandible appeared to be the preferred site. The most common type of ameloblastoma was multicystic. The histopathologic patterns were mostly follicular and plexiform.

CONCLUSIONS

This is the first study assessing the global incidence of ameloblastoma. The pooled incidence rate was determined to be 0.92 per million person-years.

A Comparison of Ki67, Syndecan-1 (CD138), and Molecular RANK, RANKL, and OPG Triad Expression in Odontogenic Keratocyts, Unicystic Ameloblastoma, and Dentigerous Cysts

BACKGROUND AND OBJECTIVE

Reduced expression of syndecan-1 (CD138), increased proliferation index, and modifications in the expression of the molecular RANK/RANKL/OPG triad are related to an intensified potential of aggressiveness and invasion of diverse tumors and cysts. The aim was to compare the expression of Ki-67, CD138, and the molecular triad RANK, RANKL, and OPG in odontogenic keratocysts (OKC), unicystic ameloblastomas (UA), and dentigerous cysts (DC).

METHODS

Immunohistochemistry for Ki-67, CD138, RANK, RANKL, and OPG was performed in 58 odontogenic cystic lesions (22 OKC, 17 DC, and 19 UA).

RESULTS

A higher expression of Ki-67 was identified in OKC as compared to UA (p < 0.0001). UA exhibited a greater loss of CD138 expression versus OKCs (p > 0.0034). RANKL was expressed higher in the epithelium (p = 0.0002) and in the stroma (p = 0.0004) of UA. DC had a lower expression of these markers.

CONCLUSION

Higher RANKL expression together with the reduction on CD138 expression in UA could be linked to a greater invasive and destructive potential, while the increased proliferation rate observed in OKC could be related to its continuous intrabony growth. The expansion of DC does not seem to be related to such factors, justifying the different therapeutic approaches proposed for each of these entities.