Molecular Analysis to Demonstrate That Odontogenic Keratocysts Are Neoplastic

Odontogenic keratocysts: A retrospective histopathological study

Introduction

Odontogenic keratocyst (OKC) is an aggressive recurrent cyst with intriguing features. Various factors such as the surgical procedure are involved, and certain histological features contribute to its recurrence. We assessed the clinical, radiographic, and histopathological data of OKCs to better comprehend the true nature of this cyst.

Material and Methods

A total of 58 lesions including four cases in association with nevoid basal cell carcinoma syndrome (NBCCS) were assessed. Radiographic features and histopathological features within the epithelium and capsule were assessed.

Results

72% of cases were seen in males and 28% in females. 43% of cases were seen in the mandibular ramus, and 65% exhibited unilocular radiolucency. 95% showed true parakeratinization. Cuboidal basal cell morphology was seen in 41.3% of cases and reversal of polarity in 60%. Basal budding, rete pegs, and mitosis were also observed within the epithelium. The epithelium showed separation at the subbasal level and suprabasal levels in 55 (94.9%) cases.

Conclusion

Features such as basal cell budding, suprabasal mitotic activity, suprabasal split, localized inflammation, subepithelial hyalinization, and satellite cysts were commonly associated with recurrent cysts. Many newer genetic and molecular hypotheses have generated path-breaking contributions to the understanding of the biology of OKC. With the guidance and help of such factors, improved post-surgery results can be anticipated.

Comparative Molecular Genetics of Odontogenic Keratocysts in Sporadic and Syndromic Patients

Odontogenic keratocysts (OKCs) are common cysts of odontogenic origin that usually occur as a single nonsyndromic cyst in isolation (sporadic) or as syndromic multiple cysts as a manifestation of naevoid basal cell carcinoma syndrome. Alterations involving the PTCH gene are the most commonly identified factor associated with up to 85% and 84% of naevoid basal cell carcinoma syndrome and sporadic cases, respectively. Other Hedgehog pathway and non-Hedgehog pathway-associated genes have been implicated in the pathogenesis of OKCs. This pilot study used the Affymetrix OncoScan molecular assay to perform a comparative genomic analysis between 4 sporadic and 3 syndromic cases of OKC to identify molecular drivers that may be common and/or distinct in these 2 groups. The majority of alterations detected in both groups were copy number neutral loss of heterozygosity. Despite distinct molecular signatures observed in both groups, copy number neutral loss of heterozygosity alterations involving chromosome 9q affecting not only PTCH but also the NOTCH1 gene were detected in all syndromic and 3 sporadic cases. Loss of heterozygosity alterations involving 16p11.2 affecting genes not previously described in OKCs were also detected in all syndromic and 3 sporadic cases. Furthermore, alterations on 22q11.23 and 10q22.1 were also detected in both groups. Of note, alterations on 1p13.3, 2q22.1, and 6p21.33 detected in sporadic cases were absent in all syndromic cases. This study demonstrates that a more common group of genes may be affected in both groups of OKCs, whereas other alterations may be useful in distinguishing sporadic from syndromic cysts. These findings should be validated in larger OKC cohorts to improve molecular diagnosis and subsequent patient management.

An evidence-based surgical algorithm for management of odontogenic keratocyst

The effective management of odontogenic keratocyst (OKC) remains a subject of interest and confusion in the oral and maxillofacial surgery literature. Currently, there is a lack of consensus regarding the most appropriate treatment for patients with OKC. Of the various treatment options available, no modality to date has been shown to demonstrate a zero or near-zero recurrence rates except wide resection with clear margins. With the prevailing dearth of evidence based surgical protocols for the management of patients with OKC in the literature, this study aims to present a surgical algorithm, based on meta-analysis results, that hopefully will be beneficial in enhancing treatment of patients with this condition. Also, new meta-analysis was done to compare between modified Carnoy's solution (MCS) and 5-fluorouracil (5-FU) in respect of recurrence rate of OKC. Using parameters like size, lesion type (primary or secondary), syndromic or solitary nature of the lesion, presence of cortical perforations, and locularity; we present a decision tree, to aid treatment planning and help attain the least chance of recurrence in the management of the OKC. There was very low-quality evidence indicating that application of 5-FU, after enucleation and peripheral ostectomy of OKCs, significantly lowered recurrence rate when compared to MCS (RR = 0.087, CI: 0.017 to 0.436, P value = 0.003).

OUP accepted manuscript

The Odontogenic Keratocyst (OKC) is one of the most aggressive odontogenic cysts. OKCs of the maxilla are particularly rare with less than 1% of cases reported in the literature. A 29-year-old female patient presented with pain and loose upper molars. Imaging confirmed an ectopic tooth at the osteomeatal complex and a maxillary OKC. These were endoscopically surgically removed and two teeth were encountered at the maxillary antrum. Histopathology confirmed the diagnosis of OKC of the maxilla. Surveillance with CT imaging and clinical assessment at 6 months shows no evidence of recurrence.

Critical assessment of the latest classification of jaw cysts proposed by the World Health Organization (2017)

Background

The fourth edition of the World Health Organization Classification of Head and Neck Tumors was published in January 2017, and includes a classification of odontogenic tumors and odontogenic cysts. The present review assesses the changes made in this new classification in relation to odontogenic and non-odontogenic jaw cysts.

Material and Methods

An electronic search was conducted in the Cochrane Library, PubMed-MEDLINE and Scopus databases using the search terms: “odontogenic cyst” “WHO classification” “update”. Studies written in English and published between January 2005 and April 2020 with a high level of scientific evidence were included, while studies not published in English, epidemiological studies, and studies with a low level of scientific evidence were excluded.

Results

The initial search identified 311 articles, and after the deletion of duplicates, 7 studies were selected for full-text assessment. After excluding two studies that failed to provide relevant information and had a low level of scientific evidence, 5 articles were finally included and stratified according to their level of scientific evidence based on the SORT (Strength of Recommendation Taxonomy) criteria.

Conclusions

The incorporation of odontogenic and non-odontogenic cysts to the head and neck tumors classification underscores the recognition of the WHO of these important disorders of the jaws. Based on the current evidence, there is controversy as to whether odontogenic keratocysts should be regarded as cystic lesions or as neoplasms, though there is no such controversy in relation to calcifying odontogenic cysts. On the other hand, orthokeratinized odontogenic cysts have been included in the classification as a single entity differentiated from odontogenic keratocysts, while residual cysts have been removed from the classification.

Key words:Odontogenic cyst, WHO classification, pseudocyst.

Ghost cell odontogenic carcinoma of the left maxilla

We report the case of a 25-year-old man with a maxillary ghost cell odontogenic carcinoma (GCOC). The patient presented to the maxillofacial and head and neck surgery clinic with a growing lump in the left maxilla. Initial workup with CT revealed a cystic lesion in the left upper jaw with associated bone erosion and an enhancing soft-tissue component. Enucleation showed a GCOC associated with a calcifying odontogenic cyst. After the diagnosis was obtained, the patient underwent widening of the first surgical resection. GCOCs are rare odontogenic neoplasms with unspecific clinical and imaging presentation, whose definitive characterisation is based on pathology. Current treatment approaches mainly involve surgical excision, but the prognosis is highly unpredictable due to intertumoral heterogeneity. As tumour recurrences occur in 73% of cases, radical surgery with negative margins is highly recommended. Therefore, it is essential to recognise this entity to offer patients adequate management.

Maspin, Syndecan-1, and Ki-67 in the Odontogenic Keratocyst: An Immunohistochemical Analysis

The odontogenic keratocyst (OKC) is a controversial lesion that was reclassified as a tumor with the name “keratocystic odontogenic tumor” in 2005. The reclassification was revoked recently in 2017, with a conclusion on the need for further studies on the subject. In this study, the expressions of an important regulatory protein (maspin), an important integral membrane proteoglycan (syndecan-1), and a universal proliferation marker (Ki-67) in the epithelium of the OKC were investigated in comparison with the dentigerous cyst (DC) and ameloblastoma (AB). Twenty-six OKCs, eleven DCs, and ten conventional ABs were immunohistochemically stained for maspin, syndecan-1, and Ki-67. ImageJ was used to analyze the positivity of maspin and syndecan-1. The Ki-67 score was calculated as the percentage of positive nuclei in 5 high power fields. Analysis of variance (ANOVA) test and Student t-test were used as appropriate. Lower expressions of maspin were noted in OKC and DC compared to those in AB, and lower expressions of syndecan-1 were noted in OKC and AB compared to those in DC. The differences, however, did not reach statistical significance (ANOVA and t-test: P > 0.05). The Ki-67 score was significantly higher in OKC than in DC (t-test: P < 0.05), and not significantly different from AB (t-test: P > 0.05). In conclusion, expressions of maspin and syndecan-1 are not strongly representative of differences in behavior between OKC, AB, and DC. However, the expression of Ki-67 indicates comparable proliferative activities of OKC and AB, which are higher than that of DC. Further investigation on the biologic behavior of OKC is still recommended to arrive at more specific conclusions regarding its classification.

A Retrospective Brazilian Multicenter Study of Biopsies at the Periapical Area: Identification of Cases of Nonendodontic Periapical Lesions

INTRODUCTION

The purpose of this study was to analyze the features of lesions obtained from biopsies at the periapical area of teeth with a radiographic or clinical initial diagnosis of apical periodontitis.

METHODS

A retrospective study was conducted on biopsies obtained from 1953-2018 at 3 Brazilian oral and maxillofacial pathology centers. Cases of endodontic and nonendodontic periapical lesions (NPLs) with a clinical diagnosis of endodontic pathoses were retrieved. Data regarding patient age, sex, and anatomic location were obtained from patients' records. The frequency and percentage of cases with clinical diagnoses of a periapical cyst, periapical granuloma, or dentoalveolar abscess were recorded, and the final histopathologic diagnosis was documented.

RESULTS

Among 66,179 oral biopsies, 7246 (10.94%) were clinically diagnosed as periapical disease, 306 (4.22%) of which were histopathologically diagnosed as NPLs. The most frequent NPLs were odontogenic keratocysts (n = 107, 34.96%) followed by dentigerous cysts (n = 48, 15.68%). The mean age at diagnosis was 39.68 years with a range of 6-80 years. A total of 159 (51.96%) cases occurred in females and 147 (48.03%) in males (female to male ratio = 1.08:1). Most lesions (137, 44.77%) were located in the posterior mandible.

CONCLUSIONS

A wide variety of histopathologic diagnoses, including benign odontogenic and nonodontogenic cystic and tumorous lesions, infectious diseases, and malignant neoplasms, was reported in the present survey. The features presented in this study were consistent with previous findings reported in the literature.

Management of an extensive odontogenic keratocyst: A rare case report with 10-year follow-up

INTRODUCTION

The odontogenic keratocyst (OKC), previously known as keratocystic odontogenic tumor has been the most disputable pathologies of the maxillofacial region. Patients with OKC are often asymptomatic but may present with pain, swelling, or discharge. Despite the aggressive nature, previous literature as early as 1970s reported the fact that parakeratinized OKC can be treated by means of marsupialization alone.

PATIENTS CONCERNS

The patient had reported with a complaint of pain and swelling in relation with a tooth in mandibular right quadrant.

DIAGNOSIS

This case report discusses features of a rare, extensive, panmandibular OKC that is only second of its kind mentioned in the literature.

INTERVENTION

As a usual treatment protocol, marsupialization was attempted first. Immunohistochemical analysis revealed reduced expression of Ki-67 and B cell lymphoma 2 (bcl-2) markers after marsupialization from 2 separate sites. However, due to incomplete resolution in the lower right anterior region, an aggressive approach was taken by curetting it out surgically along with associated teeth and cortical plate followed by application of Carnoy's solution.

OUTCOME

Postsurgery uneventful healing of the lesion was noted on regular follow-up visits with complete resolution at 40 months. The case has been followed for 10 years with no sign of relapse and reoccurrence.

CONCLUSIONS

Based on the expression of markers it can thus be concluded that Ki-67 and bcl-2 are site specific and bear strong relationship with the recurrence of OKCs.

New WHO odontogenic tumor classification: impact on prevalence in a population

Objectives:

This study approaches the history of reclassifications and redefinitions around the odontogenic keratocyst (OK), as proposed by the World Health Organization (WHO), and aims to understand the impact of those changes on the prevalence and epidemiology of odontogenic tumors (OTs).

Methodology:

Cases of OTs diagnosed in an Oral Pathology service between January 1996 and December 2016 were reviewed. Demographic data of patients such as age, gender and site of lesions were retrieved from their respective records.

Results:

Within the studied period, 7,805 microscopic reports were elaborated and 200 (2.56%) of these were diagnosed as OTs. Out of these 200, between 1996 and 2005, prior to the 2005 WHO classification, there were 41 (20.5%) OTs cases, being odontoma the most frequent (23; 56.09%), followed by ameloblastoma (8; 19.51%) and myxoma (03; 7.31%). Between 2006 and 2016, after the previous 2005 WHO classification there were 159 (79.5%) OTs, being odontogenic keratocystic tumor (KCOT) the most frequent (68; 42.76%), followed by odontoma (39; 24.52%) and ameloblastoma (21; 13.20%).

Conclusions:

As of today, the most recent WHO classification to be followed brings KCOT back to the cyst category, which will impact on the prevalence and epidemiology of OTs; thus, this study was able to identify a considerable increase (287.80%) in the prevalence of OTs when the 2005 WHO classification was utilized. Despite being an important academic exercise, classifying odontogenic lesions and determining whether to place the odontogenic keratocyst in a cyst or tumor category is crucial to establish the correct diagnosis and treatment to follow, whether by oral medicine or oral surgery specialist, or by the general practitioner.

Elevated ATF4 Expression in Odontogenic Keratocysts Epithelia: Potential Involvement in Tissue Hypoxia and Stromal M2 Macrophage Infiltration

The aim of this study was to investigate the expression of the activating transcription factor 4 (ATF4) in odontogenic keratocysts (OKC), its association with hypoxia and M2-polarized macrophages infiltration, and its potential relationships with angiogenesis in OKC. The expression of ATF4, hypoxia-inducible factor 1α (HIF-1α), macrophage colony-stimulating factor (M-CSF), and receptor activator of nuclear factor κ-B ligand (RANKL) in OKC samples and normal oral mucosa (OM) was detected by immunohistochemistry. Meanwhile, microvessel density (MVD) was measured using antibody against CD31. M2-polarized macrophages were identified using double-staining for CD68⁺ and CD163⁺. The correlations of ATF4 with HIF-1α, M-CSF, and M2-polarized macrophages infiltration were determined by Spearman's rank correlation test and hierarchical clustering. Human immortalized oral epithelial cells (HIOECs) were used in in vitro experiments. Our data showed that the expression of HIF-1α, ATF4, and M-CSF was significantly upregulated in the epithelium of OKC when compared with the OM. The expression of ATF4 was positively correlated with that of HIF-1α, M-CSF, MVD, and M2-polarized macrophages infiltration. Elevated expression of ATF4 in the epithelial lining of OKC may facilitate the M2 macrophages infiltration in response to hypoxia, leading to the development of OKC.

Odontogenic Keratocyst: Developing a Protocol for Surgical Intervention

The aim of this study was to report the outcome of a conservative treatment protocol – “enucleation and packing open” for odontogenic keratocyst (OKC). Ten patients with OKC were treated at our institute by peripheral ostectomy, enucleation followed by open packing. This conservative treatment protocol was selected because of relatively young age of the patients and relatively large size of the lesions. All the cases were monitored at regular predetermined intervals using clinical evaluation and panoramic radiographs. There was no evidence of recurrence during follow-up. The conservative treatment protocol for OKC, based on enucleation followed by open packing would be a possible choice in view of the simplicity of surgical procedure and low morbidity. This treatment modality has a low recurrence rate and may be particularly useful in young patients and patients with advanced systemic disease not amenable to major surgical intervention.

Investigation of clinicopathological parameters and expression of COX-2, bcl-2, PCNA, and p53 in primary and recurrent sporadic odontogenic keratocysts

Objectives

Odontogenic keratocyst (OKC) presents considerable variation in aggressiveness and propensity for recurrence, yet hitherto, no explicit clinicopathological features have been determined to clearly demonstrate the potential for relapse. This retrospective study aims to investigate the prognostic relevance of various clinicopathological features as well as immunoexpression of COX-2, bcl-2, PCNA, and p53 in sporadic OKC.

Materials and methods

Among 41 patients with OKC treated by enucleation, the frequency of recurrence for various clinicopathological features as well as immunoexpression for COX-2, bcl-2, PCNA, and p53 was evaluated.

Results

The mean follow-up was 8.49 years, and recurrences were ascertained in 29.27% of cases. We found significant differences between recurrent and non-recurrent cysts in terms of multilocularity (P = 0.029), cortical perforation (P = 0.001), and lesion size (P < 0.001). Hazard risk for the recurrence was 3.362 (95% CI 1.066–10.598) for multilocular cysts, 7.801 (95% CI 2.1–28.985) for evidence of cortical perforation, and 1.004 (1.002–1.006) for 1 mm² of lesion size on panoramic radiographs. We also found that immunoexpression of PCNA significantly correlates with the radiographic evidence of cortical perforation (P = 0.048) and that there is significant positive correlation between expression of COX-2 and bcl-2 (P = 0.001) as well as significant negative correlation between immunoexpression of COX-2 and age (P = 0.002). None of the other analyzed factors were associated with the recurrence.

Conclusions

Larger size, multilocularity, and cortical perforation in sporadic OKC may be correlated with the relapse.

Clinical relevance

Immunohistochemical analyses of COX-2, bcl-2, PCNA, and p53 lack prognostic utility in sporadic OKC.

[Cystic lesions of the jaws]

Cystic lesions of the jaws comprise a spectrum of inflammatory, developmental and neoplastic changes that can clinically appear strikingly similar. Squamous cell metaplasia due to superinfection can further blur the histologic hallmarks of the individual lesions. In this article an overview of the most important differential diagnoses and the novelties of the latest World Health Organisation (WHO) classification on head and neck tumours released in early 2017 is provided. In contrast to the previous edition, odontogenic cysts have been re-introduced and several changes in terminology and taxonomy have been complemented.

Frequent oncogenic BRAF V600E mutation in odontogenic keratocyst

OBJECTIVES

Odontogenic keratocyst (OKC), also known as keratocystic odontogenic tumor (KCOT), has clinical significance due to its high incidence as well as high recurrence rate after surgical enucleation. Current clinical management for OCK is entirely dependent on surgical approach. While various genetic alterations, such as PTCH1 mutation and loss of heterozygosity in tumor suppressor genes, have been reported, the molecular background of OKC is not well-understood. Although recent identification of BRAF V600E mutation and subsequent activation of mitogen-activated protein kinase (MAPK) pathway in ameloblastoma and odontogenic tumors provide additional options with targeted therapeutics, the molecular background of OKC is not well understood.

MATERIALS AND METHODS

In this study, we examined BRAF V600E mutation from paraffin embedded OKC samples by tumor cell enriched microdissection and TA cloning of amplified DNA. We further examined the relationship between BRAF V600E mutation and clinical parameters.

RESULTS

We found frequent BRAF V600E mutation in OKC (24 of 38 samples, 63.2%). However, BRAF V600E mutational status is not related with clinical indexes such as size, location, and recurrence. In orthokeratinized odontogenic cyst, there is one case of BRAF 600E mutation from 11 samples (9.1%).

CONCLUSION

These results indicate that BRAF V600E mutation occurs in OKCs at a high rate and plays an important role in the pathogenesis of OKCs.

The anecdote of viral etiopathogenia in ameloblastoma and odontogenic keratocyst: Why don't we let it go?

BACKGROUND

Ameloblastoma (AM) and odontogenic Keratocyst (OKC) are destructive odontogenic lesions of the gnathion. Although their exact pathogeneses are not yet totally understood, the viral etiopathogenesis in AM and KCOT has been proposed. True to syndromic keratocystic odontogenic tumor (sKCOT) and non-syndromic OKC is the high recurrence rate.

OBJECTIVES

Given that shared pathways trailed by AM and by sKCOT/OKC have been suggested, this study, however, contrasts the expression of AM and OKC for viral antibodies.

METHOD

A total of archival 80 paraffin blocks of cases of parakeratinized odontogenic keratocyst (non-syndromic KCOTs) and of ameloblastomas (n = 40 for each) were included in this study to be sectioned and stained for two immunohistochemical markers: anti-human papillomavirus and Epstein-Barr virus-encoded latent membrane protein.

RESULTS

All the submitted cases of AM and parakeratinized OKC were negative for both markers: anti-HPV and anti-LMP-1.

CONCLUSIONS

Although results could have been biased, given the same ethnic group and territory examined in this study, all cases were negative for both markers. Therefore, the viral contribution to the etiopathogenesis in AM and OKC could not be established in this study.

Squamous cell carcinoma arising within a maxillary odontogenic keratocyst: A rare occurrence

Squamous cell carcinoma (SCC) arising within the lining of an odontogenic keratocyst (OKC) is a rare occurrence. Although potentially locally destructive, OKC is a benign odontogenic process that typically presents with clinical and radiographic features characteristic of a benign intraosseous neoplasm. We present the clinical and radiographic features of a maxillary mass that demonstrated SCC arising from the lining of an OKC. Although the initial clinical and radiographic presentation suggested an infection or malignant neoplasm, biopsies revealed an infiltrative well-differentiated SCC contiguous with and arising from the focus of a pre-existing OKC. The patient subsequently underwent a type II hemi-maxillectomy with neoadjuvant chemoradiation. This report discusses the clinical and radiographic features associated with intraosseous malignancies, especially those arising from an otherwise benign odontogenic lesion. While the majority of OKCs are benign, the current report illustrates the potential for carcinomatous transformation within the lining of an OKC.

Analysis of GLUT-1, GLUT-3, and angiogenic index in syndromic and non-syndromic keratocystic odontogenic tumors

The aim of this study was to evaluate the immunoexpression of glucose transporters 1 (GLUT-1) and 3 (GLUT-3) in keratocystic odontogenic tumors associated with Gorlin syndrome (SKOTs) and non-syndromic keratocystic odontogenic tumors (NSKOTs), and to establish correlations with the angiogenic index. Seventeen primary NSKOTs, seven recurrent NSKOTs, and 17 SKOTs were selected for the study. The percentage of immunopositive cells for GLUT-1 and GLUT-3 in the epithelial component of the tumors was assessed. The angiogenic index was determined by microvessel count. The results were analyzed statistically using the nonparametric Kruskal-Wallis test and Spearman's correlation test. High epithelial immunoexpression of GLUT-1 was observed in most tumors (p = 0.360). There was a higher frequency of negative cases for GLUT-3 in all groups. The few GLUT-3-positive tumors exhibited low expression of this protein in epithelial cells. No significant difference in the angiogenic index was observed between groups (p = 0.778). GLUT-1 expression did not correlate significantly with the angiogenic index (p > 0.05). The results suggest that the more aggressive biological behavior of SKOTs when compared to NSKOTs may not be related to GLUT-1 or GLUT-3 expression. GLUT-1 may play an important role in glucose uptake by epithelial cells of KOTs and this process is unlikely related to the angiogenic index. GLUT-1 could be a potential target for future development of therapeutic strategies for KOTs.

Histopathological and immunohistochemical study in keratocystic odontogenic tumors: Predictive factors of recurrence

The aim of the present study was to identify the most useful markers for predicting recurrence of keratocystic odontogenic tumors (KCOTs). A total of 65 tumor samples from 63 patients diagnosed with typical parakeratinized cysts and KCOTs between 1992 and 2014 were retrospectively studied. Clinical and histopathological data and treatment modality were reviewed. In addition, the expression profiles of Ki-67, cluster of differentiation (CD)34 and podoplanin were assessed using immunohistochemistry. The association between these factors and the rate of KCOT recurrence was evaluated. The presence of daughter cysts, epithelial islands and high Ki-67, CD34 and podoplanin expression levels were revealed to be associated with tumor recurrence. In particular, univariate analysis revealed that high CD34 expression levels were significantly associated with tumor recurrence (P=0.034), as was conservative surgical treatment (P=0.003). Multivariate analysis revealed that conservative treatment was the greatest independent risk factor for tumor recurrence (odds ratio=13.337; P=0.018). These results suggest that overexpression of CD34 may be a potent predictor of tumor recurrence and radical treatment of the teeth that are in contact with the tumors is recommended in order to prevent tumor recurrence.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Odontogenic and Maxillofacial Bone Tumors

The 4th edition of the World Health Organization's Classification of Head and Neck Tumours was published in January of 2017. This article provides a summary of the changes to Chapter 4 Tumours of the oral cavity and mobile tongue and Chapter 8 Odontogenic and maxillofacial bone tumours. Odontogenic cysts which were eliminated from the 3rd 2005 edition were included in the 4th edition as well as other unique allied conditons of the jaws. Many new tumors published since 2005 have been included in the 2017 classification.

Diagnosing the most common odontogenic cystic and osseous lesions of the jaws for the practicing pathologist

Odontogenic cysts and osseous lesions are often seen as challenging diagnostic lesions but the majority of them are easily classified. This article outlines the diagnostic features required for separating the most common of odontogenic cysts and select osseous lesions of the jaws. Clinical and radiographic findings of these jaw lesions often lead to a differential diagnosis that only the histologic findings will clarify. Dentigerous cyst, keratocystic odontogenic tumor, and certain ameloblastomas that have cystic change, may have identical radiographic findings, with only separation by their specific histologic features leading to the significantly different treatments required for each. Conversely, some cystic lesions can appear histologically identical and cannot be diagnosed without the radiographic findings. Certain osseous lesions of the jaws are particularly problematic for diagnosis without the appropriate radiographic findings, and the diagnosis should probably not be attempted on the histologic findings alone. This article will integrate the necessary clinical, radiographic, and histologic findings required to address the most common odontogenic lesions.

Use of anteromedial thigh perforator flap and immunological implications of Gorlin-Goltz syndrome: a case study

Gorlin-Goltz syndrome is mainly characterised by the development of numerous multicentric and relapsing cutaneous basal cell carcinomas (BCCs). A major problem for patients with Gorlin-Goltz syndrome is the large amount of BCCs that can invade the deep underlying structures, especially the face. Here, we describe the case of a 23-year-old male affected by Gorlin-Goltz syndrome. He had recurrent BCCs on a hairless scalp and dorsum since he was 17 years old and underwent four surgical procedures to excise BCCs, including a reconstruction with anteromedial thigh perforator flap. For each of the surgical procedures, a phenotypic study on peripheral blood mononuclear cells using flow cytometry was performed on the same day of surgery, and on days 7, 14 and 21 after surgery. The role of the tumour-specific cytolytic immune response as a potential future treatment of syndromic BCCs and its trend in relation to surgical ablation of large portions of tumour tissue was examined, and the cosmetic and therapeutic results are shown.

Evaluation of keratocystic odontogenic tumors using cone beam computed tomography

Purpose:

The aim of this retrospective study is to determine the radiological features of keratocystic odontogenic tumors (KCOT) using cone-beam computed tomography (CBCT).

Materials and Methods:

CBCT images of 28 patients who had histopathologically-confirmed KCOT were retrospectively reviewed from the archives of the Department of Dentomaxillofacial Radiology, Gazi University Faculty of Dentistry. The location and size of KCOT, cortical expansion, cortical perforation, relation with the impacted teeth, and the impact on the mandibular canal were evaluated.

Results:

The mean age of patients at initial diagnosis was 34.5 years. Patients with an impacted tooth were significantly younger than those without an impacted tooth (p<0.05). Among KCOTs, 21% were localized in the maxilla whereas 79% were found in the mandible. The lesions localized in the mandible were mostly found in the retromolar-ramus region. Of these patients, 93% had cortical expansion and 75% had bone perforation. Of the 22 mandibular lesions, 20 were in close proximity of the mandibular canal and 18 (90%) of these lesions had caused destruction in the mandibular canal.

Conclusion:

KCOTs exhibit their aggressive nature in the jaw bone. CBCT is a useful radiological imaging method to examine the radiologic characteristics of KCOTs such as bone destruction and their spatial relations with the neighboring anatomic structures.

Keratocystic odontogenic tumors related to Gorlin-Goltz syndrome: A clinicopathological study

BACKGROUND

Assess clinicopathological features of patients with keratocystic odontogenic tumor (KCOT) associated with Gorlin-Goltz syndrome in our institution from 2004 to 2015.

METHOD

After histopathological analyses of KCOT related to Gorlin-Goltz syndrome, 7 patients were assessed. These patients presented a total of 15 primary and 2 recurrent KCOT.

RESULTS

All patients presented a multiple KCOT, and 13 lesions were located in mandible (77%) and 4 (23%) in maxilla. Most of the tumors presented a unilocular pattern (71%) and had tooth association (88%). Four patients (57%) were in the age group of 10-19 years and three patients (43%) were in the age group of 20-29 years. There were four male and three female patients.

CONCLUSION

KCOT is a frequent manifestation of Gorlin-Goltz syndrome and can be its first sign, mainly in young patients. The four patients presented with two lesions (57%) and three lesions in three patients (43%).

Keratocystic Odontogenic Tumour with Extraosseal Spread: Evaluation of the Effect Carnoy's Solution

Keratocystic odontogenic tumour is relatively rare benign tumour. It is characterized by its fast aggressive growth and high risk of recurrence. Treatment is always surgical: conservative (enucleation, marsupialization) or aggressive (enucleation followed by application of Carnoy's solution, cryotherapy; peripheral ostectomy or en block resection of the jaw). Authors analysed retrospectively 22 patients who fulfilled inclusion criteria, i.e. had odontogenic keratocystic tumour of mandible, wherein antero-posterior dimension was at least 30 mm, and the tumour penetrated into the surrounding soft tissues. All patients underwent tumour enucleation, in 11 patients Carnoy's solution was given into the bone cavity after enucleation. The recurrence rate in the evaluation at least 36 months after surgery was both patient groups the same: 45.4%.

Interventions for the treatment of keratocystic odontogenic tumours

BACKGROUND

The keratocystic odontogenic tumours (KCOTs) account for between about 2% and 11% of all jaw cysts and can occur at any age. They are more common in males than females with a male:female ratio of approximately 2:1. Although they are benign, KCOTs are locally very aggressive and have a tendency to recur after treatment. Reported recurrence rates range from 3% to 60%. The traditional method for the treatment of most KCOTs is surgical enucleation. However, due to the lining of the cyst being delicate and the fact that they frequently recur, this method alone is not sufficient. Adjunctive surgical treatment has been proposed in addition to the surgical enucleation, such as removal of the peripheral bone (ostectomy) or resection of the cyst with surrounding bone (en-bloc) resection. Other adjunctive treatments proposed are: cryotherapy (freezing) with liquid nitrogen and the use of the fixative Carnoy's solution placed in the cyst cavity after enucleation; both of which attempt to address residual tissue to prevent recurrence.

OBJECTIVES

To assess the available evidence comparing the effectiveness of interventions for the treatment of KCOTs.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Oral Health Group Trials Register (to 17 March 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2015, Issue 2), MEDLINE via Ovid (1946 to 17 March 2015) and EMBASE via Ovid (1980 to 17 March 2015). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the WHO Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

Randomised controlled trials comparing one modality of intervention with another with or without adjunctive treatment for the treatment of KCOTs. Adults, over the age of 18 with a validated diagnosis of solitary KCOTs arising in the jaw bones of the maxilla or mandible. Patients with known Gorlin syndrome were to be excluded.

DATA COLLECTION AND ANALYSIS

Review authors screened trials for inclusion. Full papers were obtained for relevant and potentially relevant trials. If data had been extracted, it would have been synthesised using the fixed-effect model, if substantial clinical diversity were identified between studies we planned to use the random-effects model with studies grouped by action provided there were four or more studies included in the meta-analysis, and we would have explored the heterogeneity between the included studies.

MAIN RESULTS

No randomised controlled trials that met the inclusion criteria were identified.

AUTHORS' CONCLUSIONS

There are no published randomised controlled trials relevant to this review question, therefore no conclusions could be reached about the effectiveness or otherwise of the interventions considered in this review. There is a need for well designed and conducted randomised controlled trials to evaluate treatments for KCOTs.

Magnetic resonance imaging of the maxilla and mandible: signal characteristics and features in the differential diagnosis of common lesions

The maxilla and mandible are among the most difficult areas of the body to image with magnetic resonance techniques owing to the geometry of the jaws as well as the frequent susceptibility artifacts from dental restorations or appliances. This chapter briefly reviews the essentials of imaging techniques and basic anatomy and discusses the most common inflammatory conditions, benign and malignant lesions of the jaws, and temporomandibular joint. This review emphasizes and illustrates specific magnetic resonance features that facilitate characterization and diagnostic differentiation of these lesions. As the focus of this review is on the differentiation of infection and benign and malignant disease, a discussion of internal derangements and associated inflammatory disorders of the temporomandibular joint is beyond the scope of this review and is not discussed.

Lesions of the Jaw

Imaging of lesions within the maxilla and mandible is often fraught with difficulty owing to the similarity in the imaging appearance of a diverse array of pathological processes. Principally, lesions arise from either odontogenic sources or from primary bone lesions. The response of the cancellous and cortical bone to pathologic insult can be expressed either through an osteolytic or an osteoblastic response; thus the majority of lesions within the jaws can be classified as cystic or lytic appearing, sclerotic, or a mixture of the two. This article will review the imaging features of the most common cysts, fibro-osseous lesions, benign and malignant neoplasms, and highlight those features key to the differential diagnosis.

Nevoid Basal Cell Carcinoma Syndrome: A Long-Term Study in a Family

We present a family case series with 10 individuals having nevoid basal cell carcinoma syndrome (NBCCS) with a 10-year follow-up. All articles published in the literature between 1967 and 2011 on familial Gorlin-Goltz syndrome in any language were surveyed to determine the mapping of cases per country of occurrence of this disease. All patients in the present series were presented with calcification of the falx cerebri, mild hypertelorism, and frontal bossing. Odontogenic keratocystic tumors, palmar and plantar pits, and multiple basal cell carcinomas occurred in 90, 40, and 20%, respectively, of the patients. One of the patients died of skin cancer. Diagnosis of odontogenic keratocyst tumors was confirmed by histopathological examination. NBCCS is a rare autosomal dominant cancer predisposition syndrome; it is important to recognize it when a patient has multiple odontogenic keratocyst tumors because life-long monitoring is essential for patient management.

A discussion of some advancements and some persistent difficulties in the recognition and understanding of the histopathologic and molecular features of selected odontogenic tumors and tumor-like malformations

Overgrowths of epithelial, ectomesenchymal, and/or mesenchymal elements of the tooth-forming apparatus are quite variable with respect to their histopathologic characteristics and biological behaviors. Investigations of a variety of odontogenic lesions have led to an enhanced comprehension of many salient diagnostic features. This discussion provides an update with respect to the understanding of odontogenic tumors and tumor-like malformations and attempts to assist pathologists in the recognition and classification of these lesions.

Molecular and genetic aspects of odontogenic lesions

In this article we outline the molecular findings of select odontogenic tumors. In each section, we briefly review selected the clinicoradiographic, histologic, immunologic features, focusing on the molecular findings and their applications in practice. The understanding of molecular pathobiology at various other organ sites has developed quite rapidly in recent years, however much remains unknown about the genetic profile of odontogenic tumors. Improved understanding of mutations in odontogenic tumors may clarify classification schema and elucidate targets for novel therapies. Molecular testing will no doubt improve our understanding of odontogenic tumor pathogenesis and will likely be, someday, an important component of routine clinical practice and its role will only increase in the coming years.

Odontogenic tumors, WHO 2005: where do we go from here?

As our knowledge of disease improves, its classification continually evolves. The last WHO classification of odontogenic tumors was 9 years ago and it is time for revision. We offer the following critique as a constructive, thought provoking challenge to those chosen to provide contemporary insight into the next WHO classification of odontogenic cysts, tumors, and allied conditions.

Evaluation and comparison of expression of p63 in odontogenic keratocyst, solid ameloblastoma and unicystic ameloblastoma

Background and Objectives:

The behavior of odontogenic lesions varies with some tumors behaving like a cyst and some cysts behaving like tumors. p63, a member of the p53 family of tumor suppressor genes has recently come into light in view of its role as an oncogene. The aim of the present study was to investigate the expression of p63 protein in OKC, Solid ameloblastoma, Unicystic Ameloblastoma and Follicular tissue.

Materials and Methods:

p63 expression was compared in 12 cases of OKC, 12 Solid Ameloblastoma, 14 cases of Unicystic ameloblastoma and 10 cases of Follicular tissue using immunohistochemical technique. All 48 cases were subjected to heat-induced antigen retrieval method using citrate buffer in a pressure cooker. Then the sections were stained with anti-p63 polyclonal antibody and visualized using super sensitive polymer HRP detection system. In each case, number of cells showing p63 positivity were assessed in two compartments - basal and suprabasal and compared.

Results:

Statistical analysis showed that p63 expression in the suprabasal compartment in Odontogenic keratocysts was equivalent to that of central neoplastic cells of Solid Ameloblastoma and Unicystic Ameloblastoma type 3. Statistically significant difference in the expression of p63 was observed between OKC and Unicystic Ameloblastoma Type 1 and Solid Ameloblastoma and Unicystic Ameloblastoma Type 1.

Conclusion:

We conclude that the higher expression of p63 in these odontogenic lesions correlates well with their aggressive behavior and thereby suggesting alterations in treatment modalities.

Expression of inducible nitric oxide synthase in the epithelial linings of odontogenic keratocyst, dentigerous cyst and radicular cyst: a pathological insight

BACKGROUND

The present study is aimed at analyzing the expression of inducible nitric oxide synthase (iNOS) in the epithelial lining of odontogenic keratocyst (OKC), dentigerous cyst (DC), radicular cyst (RC) in order to understand the possible role of iNOS with special reference to its neoplastic nature and local aggressive of cysts.

AIM

The primary aim of the following study is to analyze the immunohistochemical expression of iNOS and secondary aim is to compare the iNOS expression, pattern and intensity of staining among the epithelial linings of OKC, DC and RC.

MATERIALS AND METHODS

iNOS in the epithelial lining cells were analyzing in 10 OKC's, 10 DC's and 10 RC's using immunohistochemistry. The percentage of positive cells was assessed and presented as mean ± standard deviation. The correlation with respect to the intensity and percentage of staining within the epithelial linings of OKCs, DCs and RCs was carried out using (analysis of variance and Student's t-test) Chi-square test.

RESULTS

Staining intensity of iNOS portion was seen in the entire thickness of the epithelial linings of OKC, whereas in DC's only one case had entire thickness of the epithelial lining staining and in RC's none of the cases showed entire thickness of staining. On comparing the staining intensity of iNOS between OKC, DC and RC groups, using Chi-square test, there was a statistically significant difference between these groups (P < 0.01). On analyzing the immuno-reactivity of iNOS in OKC, DC and RC there was a positive variable expression iNOS between the cysts.

CONCLUSION

iNOS was over expressed in OKCs when compared with DC and RC suggesting that iNOS may contribute to the aggressive behavior of OKC. This is yet another evidence to support that OKC is the neoplasm.

An overview of molecular and genetic alterations in selected benign odontogenic disorders

CONTEXT

Some dental abnormalities have environmental causes. Other odontogenic alterations are idiopathic and may have hereditary etiologies. Investigations of these conditions are ongoing.

OBJECTIVE

To provide a discussion of developmental odontogenic abnormalities and benign odontogenic overgrowths and neoplasms for which genetic alterations have been well demonstrated and well documented.

DATA SOURCES

Relevant peer-reviewed literature.

CONCLUSIONS

The understanding of benign odontogenic lesions at a molecular level is rather well developed for some lesions and at the initial stages for many others. Further characterization of the molecular underpinnings of these and other odontogenic lesions would result in an enhanced comprehension of odontogenesis and the pathogenesis of a variety of odontogenic aberrations. These advancements may lead to better prevention and treatment paradigms and improved patient outcomes.

Proteomics profiling of keratocystic odontogenic tumours reveals AIDA as novel biomarker candidate

BACKGROUND

Keratocystic odontogenic tumour (KCOT) is a benign, yet aggressive odontogenic tumour. Herein, proteome analysis of KCOT lesions in comparison with control patient-matched tissue unaffected by the disease and with inflammatory odontogenic cysts, namely radicular cysts is presented.

METHODS

For the proteomics profiling, two complementary proteomics techniques MALDI-MS/MS and LC-ESI-MS/MS were employed. Potential candidate biomarkers were validated by immunohistochemistry.

RESULTS

More than 43 proteins were found to be differentially expressed or up-regulated in KCOT lesions in comparison with patient-matched unaffected oral mucosa. These proteins bear important biological functions and are involved in cell proliferation, cytoskeletal re-organization, transcription, cellular motility and apoptosis. In particular, a number of differentially expressed proteins participate in autocrine regulation and signalization within JNK and p38 MAPK signalling pathways.

CONCLUSIONS

Immunohistochemical validation of chosen putative biomarkers revealed axin interaction partner and dorsalization-antagonist (AIDA), known as a protein that blocks activation of JNK signalling pathway, as a differential biomarker for KCOT lesions on an independent cohort of KCOT tissue samples in comparison with most prevalent intra-oseal lesions inflammatory odontogenic cysts.

Possible recurrence of keratocyst in nevoid basal cell carcinoma syndrome: A review of literature

This review will highlight some current areas of difficulty or controversy in diagnosis and treatment of nevoid basal cell carcinoma syndrome (NBCCS). The odontogenic keratocyst (OKC) has significant growth capacity and recurrence potential and is occasionally indicative of the NBCCS. The objective of this study is to clarify the causes of the recurrence of OKC in NBCCS. A literature search was conducted using Medline, accessed via the National Library of Medicine PubMed interface, searching for articles relating to the cause of recurrence of keratocyst in NBCCS written in English. This study has described the previous and the current outcomes of the treatment of OKC (recurrent cause). A protocol was then agreed to search for the possible causes of keratocyst recurrence in NBCCS. The general treatment of other manifestation of NBCCS has excluded from this study. Studies describing cohort, case series and miscellaneous clinical reports were retrieved and evaluated from 2010 to 2012.

The large intracellular loop of ptch1 mediates the non-canonical Hedgehog pathway through cyclin B1 in nevoid basal cell carcinoma syndrome

Mutations in the transmembrane receptor patched homolog 1 (Homo sapiens) (ptch1) are responsible for nevoid basal cell carcinoma syndrome (NBCCS), an autosomal dominant disorder that causes developmental abnormalities and predisposes the affected individuals to cancer. Many of these mutations, including mutations in the C-terminus of the large intracellular loop (ICL) of ptch1 (p.C727VfsX745 and p.S733IfsX736), result in the premature truncation of the protein. The ptch1‑C727VfsX745 and ptch1-S733IfsX736 mutations have been identified in patients with NBCCS‑associated keratocystic odontogenic tumors (KCOTs). In the present study, we found that the molecular mechanisms regulated by the non-canonical Hedgehog (Hh) signaling pathway through cyclin B1 are involved in the pathogenesis of NBCCS-associated KCOTs. In contrast to wild-type ptch1, ptch1-C727VfsX745 and ptch1‑S733IfsX736 clearly exhibited reduced binding to cyclin B1. Moreover, the cells expressing these two mutations demonstrated an increase in cell cycle progression and these two mutation constructs failed to inhibit cell proliferation. In addition, the mutants enhanced the activity of glioma-associated oncogene family zinc finger 1 (GLI1), a downstream reporter of Hh signaling. Thus, our data suggest that the non-canonical Hh pathway mediated through ptch1 and cyclin B1 is involved in the pathogenesis of NBCCS-associated KCOTs. The C-terminus of ICL in ptch1 may also be a potential therapeutic target in the treatment of this disease.

Endoplasmic Reticulum Stress-Associated Chaperones, Bip/GRP78 and Calnexin are Overexpressed in Keratocystic Odontogenic Tumours

Objectives

Odontogenic keratocysts (OKCs) are developmental cysts that have been reclassified according World Health Organization (WHO), to keratocystic odontogenic tumours (KCOTs), a term that better reflects their neoplastic nature. The aim of present study is to evaluate the induction of stress of the endoplasmic reticulum and execution of the resulting unfolded protein response in keratinocystic odontogenic tumours.

Material and Methods

We analyzed by immunohistochemistry the expression of the chaperones BiP/GRP78 and calnexin in 24 cases of KCOTs. As controls, we have used 9 cases of periapical or radicular cysts (PACs) and 5 cases of Fibromas (FBs). The PACs and the FBs were included in the analysis, as PACs are the most common type of inflammatory odontogenic cysts of and FBs, as lesions of the connective tissue with unaffected epithelium.

Results

Analysis revealed a strong association between both BiP/GRP78 and calnexin expression and KCOTs: 18 out of 24 (75%) KCOTs expressed BiP/GRP78 as opposed to 1 out of 9 (13%) PACs, and none of 5 FBs evaluated (P < 0.001, x²-test). Calnexin was expressed in 11 out of 24 KCOTs (46%) but only one out of 9 (13%) PACs, and none of the 5 FBs analyzed (P < 0.001, x²-test).

Conclusions

Study results imply that induction of endoplasmic reticulum stress maybe of diagnostic value in keratocystic odontogenic tumours characterization. In addition to recent findings suggesting that endoplasmic reticulum stress plays a causative role in keratinization of epithelia, pharmacological interference with the execution of the unfolded protein response should be considered for the management of keratocystic odontogenic tumours.

Keratocystic odontogenic tumour arising as a periapical lesion

AIM

To document a case of a keratocystic odontogenic tumour (KOT) involving the apical region in the maxilla mimicking a periapical lesion of endodontic origin.

SUMMARY

Benign and malignant tumours, including odontogenic lesions, can be erroneously diagnosed as periapical radiolucencies. KOTs mimicking periapical lesions of endodontic origin are uncommon, especially when the lesions involve the maxilla. This article describes a 55-year-old man with a well-delimited, oval-shaped, radiolucent lesion, occupying the middle and apical third of teeth 22 and 23. After 30 days, the clinical and radiographic findings remained unchanged and the patient was referred for surgical removal of the lesion. Clinical, radiographic and histopathological features are also discussed and compared with current literature.

Gorlin and goltz syndrome: a case report with surgical review

Gorlin and Goltz syndrome are a very complex syndrome and a multisystemic process that is characterized by the presence of multiple pigmented basocellular carcinomas, keratocysts in the jaws, palmar and/or plantar pits and calcification of the falx cerebri. Along with these major features a great number minor features have also been described which involves numerous skeletical, dermatology related, neurological, ophthalmological and reproductive anomalies. It exhibits high penetrance and variable expressivity. Presented here is the case of Gorlin-Goltz in a 12 years old male patient which was diagnosed through its oral and maxillofacial manifestations. Treatment of odontogenic keratocyst was done by enucleation without primary suturing. Iodoform dressing was kept to enhance the healing and to reduce the recurrence of the lesion.

It is important to provide the early diagnosis for detection of clinical and radiological manifestations in young patients and for provision of advice concerning preventive treatment like protection of the skin from the sunlight and genetic sensitivity testing so that possible complications associated with this syndrome can be prevented.

How to cite this article: Bahadure RN, Jain ES, Badole GP. Gorlin and Goltz Syndrome: A Case Report with Surgical Review. Int J Clin Pediatr Dent 2013;6(2):104-108.

Malignant transformation of keratocystic odontogenic tumor: two case reports

INTRODUCTION

Keratocystic odontogenic tumors (KCOTs) are cystic tumours originating from the dental lamina of the maxilla and mandible that are lined with keratinized epithelium. While benign, they can be locally destructive and have a high recurrence rate despite treatment. Rarely, KCOTs may undergo malignant transformation into Primary Intraosseous Squamous Cell Carcinoma (PIOSCC).

CASE REPORT

This study reports the clinical findings, radiological scans and histopathology of 2 patients with KCOTs that underwent malignant transformation into PIOSCC.

DISCUSSION

A comprehensive literature review was performed to similar reports documenting the malignant transformation of KCOTs. The potential for KCOTs to undergo malignant change should prompt oral maxillofacial surgeons and otolaryngologists to exercise a high index of suspicion when treating these lesions. Patients persisting with unresolved disease after treatment should be investigated for malignant transformation. Detailed histopathological examination of KCOT specimens is recommended to detect small foci of SCC which may be present in the epithelium.