Immunohistochemical Expression of CK14 and Bcl-2 in Odontogenic Keratocyst and Its Variants

Odontogenic keratocysts (OKCs) are aggressive cystic jaw lesions with a high epithelial turnover rate and increased propensity for recurrence. Sometimes, the characteristic histopathological features of OKCs are either completely lost or seen focally due to previous marsupialization or inflammation. This research aimed to determine whether specific patterns of CK14 and Bcl-2 staining could assist in diagnosing OKCs with altered epithelial features and provide clues in elucidating their aggressive nature. CK14 expression was restricted to basal and suprabasal layers near satellite cysts and in areas showing subepithelial split. The entire epithelial lining showed CK14 expression in areas of inflammation and after marsupialization. The typical basal/suprabasal staining of Bcl-2 was lost in areas of inflammation and intensity is decreased in OKCs after marsupialization. These new findings could offer a hint into the biological nature and pathogenesis of OKCs. Because of its therapeutic consequences and high recurrence rate, proper recognition and diagnosis are essential for treatment planning.

Odontogenic Keratocyst With Moderate Epithelial Dysplasia: A Rare Entity

We present a rare case of odontogenic keratocyst (OKC) with moderate epithelial dysplasia in a 47-year-old male patient. He presented with a history of pain and swelling on the right side of his face for the past three months. The radiograph revealed multi-locular radiolucency involving the ramus, coronoid process, and condylar process of the right mandible. We have discussed the cytology, incisional biopsy, radiological investigations, surgical management, reconstruction, excisional biopsy report, and follow-up of this rare entity.

Discovery of metabolite biomarkers for odontogenic keratocysts

INTRODUCTION

Odontogenic keratocysts (OKCs) are locally aggressive and have a high rate of recurrence, but the pathogenesis of OKCs is not fully understood. We aimed to investigate the serum metabolomic profile of OKCs and discover potential biomarkers.

METHODS

Metabolomic analysis was performed on 42 serum samples from 22 OKC patients and 20 healthy controls (HCs) using gas chromatography‒mass spectrometry to identify dysregulated metabolites in the OKC samples. LASSO regression and receiver operating characteristic (ROC) curve analyses were used to select and validate metabolic biomarkers and develop diagnostic models.

RESULTS

A total of 73 metabolites were identified in the serum samples, and 24 metabolites were dysregulated in the OKC samples, of which 4 were upregulated. Finally, a diagnostic panel of 10 metabolites was constructed that accurately diagnosed OKCs (sensitivity of 100%, specificity of 100%, area under the curve of 1.00).

CONCLUSION

This study is the first to investigate the metabolic characteristics and potential metabolic biomarkers in the serum of OKC patients using GC‒MS. Our study provides further evidence to explore the pathogenesis of OKC.

Digital pathology-based artificial intelligence models for differential diagnosis and prognosis of sporadic odontogenic keratocysts

Odontogenic keratocyst (OKC) is a common jaw cyst with a high recurrence rate. OKC combined with basal cell carcinoma as well as skeletal and other developmental abnormalities is thought to be associated with Gorlin syndrome. Moreover, OKC needs to be differentiated from orthokeratinized odontogenic cyst and other jaw cysts. Because of the different prognosis, differential diagnosis of several cysts can contribute to clinical management. We collected 519 cases, comprising a total of 2 157 hematoxylin and eosin-stained images, to develop digital pathology-based artificial intelligence (AI) models for the diagnosis and prognosis of OKC. The Inception_v3 neural network was utilized to train and test models developed from patch-level images. Finally, whole slide image-level AI models were developed by integrating deep learning-generated pathology features with several machine learning algorithms. The AI models showed great performance in the diagnosis (AUC = 0.935, 95% CI: 0.898-0.973) and prognosis (AUC = 0.840, 95%CI: 0.751-0.930) of OKC. The advantages of multiple slides model for integrating of histopathological information are demonstrated through a comparison with the single slide model. Furthermore, the study investigates the correlation between AI features generated by deep learning and pathological findings, highlighting the interpretative potential of AI models in the pathology. Here, we have developed the robust diagnostic and prognostic models for OKC. The AI model that is based on digital pathology shows promise potential for applications in odontogenic diseases of the jaw.

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.

Comparison of the effectiveness of 5-Fluorouracil and modified Carnoy's solution in reducing the recurrence of odontogenic keratocyst

Introduction

Odontogenic keratocysts (OKC) has a high potential for recurrence. Resection is currently the only fool-proof method to ensure that recurrence does not occur; however, it drastically affects the patient's function and aesthetics. Application of modified Carnoy's solution (MCS) as an adjunct to reduce the recurrence rate is currently in vogue. 5- Flurouracil (5-FU) is an anti-metabolite that has been used in the treatment of basal cell carcinoma and is relatively safer than MCS. The present study aims to compare the effectiveness of 5-UC and MCS in reducing the recurrence rate in OKC..

Material and methods

A total of 42 OKCs were enucleated followed by application of MCS (control group, n = 21) or 5-FU dressing (study group, n = 21) following enucleation. Pain, swelling, temporary and permanent paresthesia paresthesia, bone sequestrum formation, osteomyelitis and recurrence in both groups were evaluated at periodic intervals up to 12 months post-surgery.

Results

There was no significant difference in terms of pain, or swelling in both groups. Permanent paresthesia and recurrence rates were higher in patients treated with MC but the difference was not statistically significant.

Conclusion

5-FU is an easy-to-use, feasible, biocompatible and cost-effective alternative for MCS in the management of OKCs. Treatment with 5-FU, therefore, reduces the risk of recurrence and also the post-surgical morbidity associated with other treatment procedures.

Factors Influencing the Aggressive Behavior of Odontogenic Keratocyst: A Narrative Review

During odontogenesis, the dental lamina disintegrates, leaving behind the remnants. Odontogenic pathologies such as cysts and tumors can arise from these remnants. The odontogenic keratocyte (OKC) arises from dental lamina remnants. Among the cysts, the odontogenic keratocyst is the most controversial. There is convincing evidence that inflammation plays a significant role in the pathogenesis and expansion of OKCs. Several factors mediate the proliferative capacity of the epithelial lining. The presence of mast cells close to the epithelial lining, cystic pressure build-up by vascular endothelial growth factors (VEGFs), and other cytokines contribute to the cystic expansion. Fibroblast activation by inflammation in the connective tissue stroma and changes in the epithelial lining are responsible for the aggressive nature of OKC. The use of molecular methodologies gives more profound insights into the factors influencing the progression of the lesion and helps develop newer treatment modalities for OKC. This review describes the characteristics that determine the aggressive behavior of this unique cyst.

Ensemble Deep-Learning-Based Prognostic and Prediction for Recurrence of Sporadic Odontogenic Keratocysts on Hematoxylin and Eosin Stained Pathological Images of Incisional Biopsies

(1) Background: Odontogenic keratocysts (OKCs) are enigmatic developmental cysts that deserve special attention due to their heterogeneous appearance in histopathological characteristics and high recurrence rate. Despite several nomenclatures for classification, clinicians still confront challenges in its diagnosis and predicting its recurrence. This paper proposes an ensemble deep-learning-based prognostic and prediction algorithm, for the recurrence of sporadic odontogenic keratocysts, on hematoxylin and eosin stained pathological images of incisional biopsies before treatment. (2) Materials and Methods: In this study, we applied a deep-learning algorithm to an ensemble approach integrated with DenseNet-121, Inception-V3, and Inception-Resnet-V3 classifiers. Around 1660 hematoxylin and eosin stained pathologically annotated digital images of OKC-diagnosed (60) patients were supplied to train and predict recurrent OKCs. (3) Results: The presence of SEH (p = 0.004), an incomplete epithelial lining, (p = 0.023), and a corrugated surface (p = 0.049) were the most significant histological parameters distinguishing recurrent and non-recurrent OKCs. Amongst the classifiers, DenseNet-121 showed 93% accuracy in predicting recurrent OKCs. Furthermore, integrating and training the traditional ensemble model showed an accuracy of 95% and an AUC of 0.9872, with an execution time of 192.9 s. In comparison, our proposed model showed 97% accuracy with an execution time of 154.6 s. (4) Conclusions: Considering the outcome of our novel ensemble model, based on accuracy and execution time, the presented design could be embedded into a computer-aided design system for automation of risk stratification of odontogenic keratocysts.

Histopathologic Feature of Hyalinization Predicts Recurrence of Conventional/Solid Multicystic Ameloblastomas

The histologic properties of tumors seem to affect their biological behavior, and the same holds good for solid multicystic ameloblastoma (SMA), a benign, locally destructive lesion. Hyalinization is one such histological factor that has been demonstrated to correlate with the biological behavior of neoplasms. The present study aimed to analyze the correlation between the severity of hyalinization (SOH) and the recurrence potential of SMAs. The study was performed on formalin-fixed, paraffin-embedded (FFPE) diagnosed archival cases of SMA, follicular SMA (n = 35) and plexiform SMA (n = 25). The cases were evaluated for SOH and scored from 0–3, and the correlation between SOH and recurrence was analyzed for statistical significance. The clinical parameters of the lesion were analyzed for statistical correlation with recurrence. The SOH significantly correlated with the recurrence of SMA (p = 0.001). The histologic type did not influence the biological behavior of SMA. The location of SMA in the body of the mandible (p = 0.036), multilocular radiolucency (p = 0.001) and root resorption (p = 0.002) also showed strong statistical correlation with recurrence. It is evident from the present study that hyalinization strongly correlates with the biological behavior of SMA. Future studies with advanced investigations could validate the presence of hyalinization and identify the origin of the hyalinized product in SMAs.

Subepithelial Hyalinisation Predicts Recurrence of Unicystic Ameloblastomas

The inductive effect of hyalinisation and its influence on the biologic behaviour of ameloblastoma variants represent a scarcely researched domain of oral pathology. The complexity of the induction effects within the odontogenic apparatus, with the involvement of both ectodermal and mesodermal tissues, is responsible for diverse histopathological characteristics, hyalinisation being the major feature. The present study aims to deduce for the first time the correlation between the severity of hyalinisation (SOH) and recurrence in three unicystic ameloblastoma (UA) variants, namely, intra-luminal (UA-IL), luminal (UA-L) and mural (UA-M). Retrospectively diagnosed archival cases of UA-IL (n = 08), UA-L (n = 22) and UA-M (n = 30) were assessed for SOH and its correlation with recurrence. A subgroup comparison (between UA-IL/UA-L and UA-M) was also performed. The clinical parameters of the patients were also analysed from files for clinicopathological correlation with recurrence. Results: sub-epithelial hyalinisation (SEH) significantly correlated with the recurrence of UA-L and UA-M (p = 0.001). When the histologic types (UA-L and UA-IL vs. UA-M) were grouped and the correlation of SOH with recurrence was checked, it was observed that both groups (p = 0.001) showed strong statistical correlation. UA-M lesions with multilocular radiolucency (p = 0.001) also showed significant correlation with recurrence. SOH can be a reliable histological predictor of recurrence and of aggressive biologic behaviour in UA. The present study shows a significant association of hyalinisation with the biologic behaviour of UA. Further studies with immunohistochemical investigations could validate the presence of hyalinisation and identify the origin of the hyalinised product in UAs.

Orthokeratinized odontogenic cyst: A large series and comprehensive literature review with emphasis on synchronous multiple occurrence and neoplastic transformation

OBJECTIVES

The objective of this study was to demonstrate the clinical, radiologic, and histologic features of orthokeratinized odontogenic cyst (OOC); determine the characteristics of multiple OOCs; and present rare but significant manifestations of OOC.

STUDY DESIGN

A clinical, radiologic, and histopathologic study of 65 primary and 2 recurrent OOC cases was performed retrospectively along with a comprehensive literature review.

RESULTS

OOCs shared similar radiologic findings with odontogenic keratocyst, yet some showed features that have not been previously described: root resorption and radiopaque foci. Histologic review revealed a unique histiocytic lining and some findings suggestive of the multipotentiality of the odontogenic epithelium. The analysis of patients with multiple OOCs demonstrated that multiple OOCs occurred synchronously with a marked predilection for young male adults. Two unusual cases were also identified: an OOC combined with a BRAF^V600E ameloblastoma and a recurrent OOC with malignant transformation.

CONCLUSIONS

This largest series presents previously unreported radiographic and histopathologic features that can be seen in OOC. Multiple OOCs have clinical characteristics distinct from those of solitary cases. The first reported OOC associated with ameloblastoma suggests the involvement of oncogenic mutations in odontogenic tumorigenesis. Although OOC shows a low recurrence rate, the possibility of malignant transformation of recurrent OOCs should be emphasized.

Novel recurrence risk stratification of odontogenic keratocysts: A systematic review

The aim of this study was to identify all clinical, radiological, histopathological, and immunohistochemical features associated with recurrence of odontogenic keratocysts (OKCs) in the literature and formulate a recurrence risk stratification based on these findings. A search was performed in PubMed/Medline, Scopus, Web of Science, Google Scholar and Cochrane databases for clinical and laboratory studies reporting on clinico-pathological features that led to OKC recurrences for the period 2000 to 2020. Twenty-three studies were identified and analyzed qualitatively. A total of 2064 OKCs were included of which 439 OKCs were recurrent with a mean follow-up period of 46.7 months. Significantly associated parameters with OKC recurrence included age (variable age categories), large (>4 cm), multilocular lesions with cortical perforation, association with dentition, presence of daughter cysts, and epithelial budding. Immunohistochemical markers including high Ki67 index and AgNOR count were also implicated. A recurrence risk stratification was formulated based on these findings. Although the level of evidence from the included studies was low, there was considerable evidence that the clinico-pathological parameters identified were linked with higher OKC recurrence. The surgeon, radiologist, and pathologist should aim to identify these features when making a diagnosis so as to determine the appropriate management regime and prevent recurrences.

Hyalinization as a histomorphological risk predictor in oral pathological lesions

Background

Hyalinization is a process of conversion of stromal connective tissue into a homogeneous, acellular translucent material. Nevertheless, hyalinization could provide insights into the biologic behaviour and prognosis of pathological lesions. Few studies with limited sample size have intended to assess the correlation of hyalinization and biologic behaviour in oral lesions.

Aim

The current review aims to comprehensively appraise the mechanism of hyalinization in pathological oral hyalinizing lesions (OHL) and its clinical implications with emphasis on differential stains employed.

Methods

An electronic search was performed in the PubMed database (from year 2000-2020) using the keywords "special stains in oral hyalinizing lesions", "significance of hyalinization in oral lesions" and "hyalinization and biologic behaviour". Original research articles analyzing the effect of hyalinization on biologic characteristics of the lesion were evaluated in this review. Narrative review articles that provided insights into the mechanism of hyalinization and maturity of collagen fibers were also considered for analysis.

Conclusion

The presence of hyalinization does seem to have a significant effect on the biologic behaviour of pathological lesions. There is substantial scope to further investigate the process of hyalinization on larger samples and its correlation with the aggressive behaviour of OHLs. Special stains and advanced investigations such as immunohistochemistry for stromal markers would define the nature of hyalinized material and validate the correlation.

Clinical significance

The prediction of the biologic behaviour of a lesion established through assessment of hyalinization would prevent unwanted over or under treatment leading to a better prognosis.

Developmental Odontogenic Lesions Associated with the Crown of an Impacted Tooth: A Guide to the Distinct Histologic Features Required for Classification

Odontogenic cysts are categorized as inflammatory and developmental. Of the developmental odontogenic cysts, the dentigerous cyst is the most common and by definition is attached to the cervical region of an unerupted tooth. The cyst envelops the crown forming a sac. However, there are other developmental cysts, and rarely, odontogenic tumors, that can have a similar clinical and radiographic presentation as dentigerous cyst, including odontogenic keratocyst, orthokeratinized odontogenic cyst and ameloblastoma, unicystic type. Understanding the key histologic differences of these cysts will aid the pathologist to correctly diagnose these lesions, ensuring appropriate clinical management.

Clinicopathological Profile of 80 Cases of Unicystic Ameloblastoma Aided by a Histopathological Comparison Using Modified Philipsen-Reichart Classification and Marx-Stern Classification

Unicystic ameloblastoma (UA) is an uncommon variant of ameloblastoma and behaves totally different from the solid multicystic variant of ameloblastoma (SMA); furthermore the histological subgroups of UA also show varied behavior regarding proliferation. The present multi-centric study was designed to present the clinicopathological features of unicystic ameloblastoma (UA) and to compare the two popular histological classifications systems. 80 satisfactory cases of UA were retrieved and evaluated for clinicopathological parameters from four teaching dental schools of North India. The cases were classified using modified Reichart and Philipsen system and Marx and Stern system followed by comparison of inter-observer variability. The results were analyzed using SPSS software. The mean age of occurrence was 30.79 ± 16.49 years. Males outnumbered females (M:F::1.67:1). The majority of cases occurred in the third decade irrespective of the gender. Most cases were found in body-angle-ramus region of the mandible. The modified Reichart and Philipsen classification yielded better interobserver agreement (kappa value 0.845). The modified Reichart and Philipsen classification yields better inter-rater agreement and is easy to reproduce amongst oral pathologists. Being simpler it may easily be understood by the operating surgeon for better treatment outcome.

Evaluation of the Connective Tissue Wall in Sporadic Cases of Keratocystic Odontogenic Tumor (KCOT) Using MMP-9 and Confocal Microscopy: A Retrospective Study

Background:

Keratocystic odontogenic tumor (KCOT) is an odontogenic lesion which manifests distinct biological behavior. Predominant studies in KCOT attribute this behavior to high epithelial proliferative capacity. Besides, a few studies facet loosely arranged collagen can contribute to the behavior of KCOT. Matrix metalloproteinases (MMP) are enzymes that degrade extracellular matrix components under both physiologic and pathologic conditions. The loosely arranged collagen in connective tissue wall of KCOT could be related to the degree of MMP-9 expression.

Aim:

To evaluate the arrangement of collagen fibers along with immunoexpression of MMP-9 and to relate to its neoplastic biologic behavior in sporadic cases of KCOT.

Materials and Methods:

KCOT ( n = 23) and dentigerous cyst (DC) ( n = 15) samples were processed for the following techniques: Masson’s trichrome stain for light microscopy, PMA-PSR stain for confocal microscopy, and MMP-9 for immunohistochemistry.

Results:

In Masson’s trichrome analysis, correlation of collagen fiber arrangement in the deeper regions with color intensity for KCOT was found to be statistically significant ( P = .033). In confocal microscopy, there was no difference between intensities in KCOT ( P = .990) and DC ( P = .233), respectively. The immunoexpression of MMP-9 in the connective tissue wall of DC (73.3%) was relatively higher than that of KCOT (60.8%). However, on comparison between KCOT and DC in the presence of inflammation, the immunoexpression of MMP-9 was higher in DC (100%) than KCOT (69.9%) and was statistically significant ( P = .028).

Conclusion:

It was concluded that the loose connective tissue wall in KCOT is because of the inherent nature of the lesion that could facilitate its biologic behavior. If inflammation is present, this could further aggravate the tumorigenic behavior.

Sub-epithelial hyalinization, incomplete cystic lining, and corrugated surface could be a predictor of recurrence in Odontogenic Keratocysts

BACKGROUND

Odontogenic Keratocysts (OKCs) are known for their rapid growth and tendency to invade the adjacent tissues. Its high recurrence rate (2.5%-62%) has attracted many kinds of research to identify new parameters to predict recurrence that would enable better treatment outcomes for such patients. The present study aims to correlate Sub-Epithelial Hyalinization (SEH) that has not been explored in an Asian population to date and other histopathologic features of OKC to its recurrence propensity.

MATERIALS & METHODS

A total of 60 OKCs were analyzed for histopathologic correlation of thickness of lining, complete/incomplete lining, corrugated surface, ortho/para keratinization, intercellular edema, reversed polarity, basilar hyperplasia, the palisading arrangement of basal cells, presence/absence of rete pegs, folding of the epithelium, epithelial/connective tissue separation, SEH, basal offshoots, daughter cysts and inflammation with recurrence to arrive at the most significant histologic feature predicting recurrence.

RESULTS

The most significant histologic parameter differentiating recurrent and non-recurrent OKCs was the presence of SEH (p = 0.004), incomplete lining epithelium (p ​= ​0.023), and a corrugated surface (p ​= ​0.049). Several other histologic parameters evaluated did not statistically correlate with recurrence, this can be attributed to the smaller sample size considered in the present study.

CONCLUSION

SEH is a reliable histologic parameter to predict recurrence in OKCs. The presence of SEH is indicative of a higher recurrence potential in OKCs. Evaluation of histological parameters and their correlation with recurrence in OKCs on a larger sample size could validate the results of the current study undertaken and potentially unravel more insights on predicting recurrence.

KEY MESSAGES

Sub-epithelial hyalinization is a significant feature for predicting recurrence in OKC.

Recurrence-free survival and prognostic factors of odontogenic keratocyst: a single-center retrospective cohort

PURPOSE

The aim of the present study was to evaluate the 5-year recurrence-free survival and prognostic factors of odontogenic keratocyst (OKC) from a single-center retrospective cohort in the northeastern region of Brazil.

METHODS

Forty cases of OKC comprised the study population. In the cohort analyzed, 18 (45%) cases were recurrent OKCs and 22 (55%) were non-recurrent OKCs. Recurrence-free survival was defined as the period from the release of the histopathological report to the occurrence of relapse or last visit to the service.

RESULTS

Comparison of the clinicopathological variables between primary and recurrent OKC lesions revealed no differences in the frequency of epithelial thickness, presence of satellite cysts and cystic spaces, presence of an inflammatory infiltrate, locularity, and lesion borders. The frequency of symptoms was practically the same even after recurrence. Satellite cysts were more frequent in the group of recurrent lesions (n = 9, p = 0.002) and the presence of an inflammatory infiltrate was also significantly associated with recurrent lesions (n = 15, p = 0.006). Previous decompression or marsupialization was associated with recurrence of the lesion (p = 0.010).

CONCLUSIONS

In conclusion, the most significant prognostic factors were previous decompression or marsupialization, as well as, morphological parameters associated with the recurrence cases were the presence of an inflammatory infiltrate and satellites cysts. The risk of recurrence is low but continues due to the particularities of epithelial proliferation in OKC.

Odontogenic keratocyst: Analysis of recurrence by AgNOR, p53 and MDM2 profiling

Background:

Odontogenic keratocyst (OKC) is a clinical entity with characteristic microscopic features, high growth potential and propensity to recur. Aggressive behavior and higher tendency for recurrence have been attributed to greater proliferative activity of epithelial lining. The incidence of recurrence in various reported series ranges from 2.5% to 62%.

Objectives:

The objective of the study was to investigate the clinical behavior of OKC by evaluating p53, MDM2 expression, AgNOR staining and to ascertain if the expression of these markers correlate with the clinical outcome and tendency for recurrence.

Materials and Methods:

All recurrent and nonrecurrent OKCs from the archives were included, and sections were subjected to AgNOR staining, p53 and MDM2 immunohistochemical staining.

Results and Conclusion:

There was a significant difference in the staining pattern of MDM2 and AgNOR in the recurrent group as compared to the nonrecurrent group. The higher expression of these markers in recurrent lesions may be important in order to consider additional surgical interventions to improve prognosis.

Assessment of expression of podoplanin in odontogenic tumors and cysts—An immunohistochemical study

Aim:

Materials and Methods:

Results:

Conclusion:

Odontogenic Cysts and Neoplasms

This article reviews a myriad of common and uncommon odontogenic cysts and tumors. The clinical presentation, gross and microscopic features, differential diagnosis, prognosis, and diagnostic pitfalls are addressed for inflammatory cysts (periapical cyst, mandibular infected buccal cyst/paradental cyst), developmental cysts (dentigerous, lateral periodontal, glandular odontogenic, orthokeratinized odontogenic cyst), benign tumors (keratocystic odontogenic tumor, ameloblastoma, adenomatoid odontogenic tumor, calcifying epithelial odontogenic tumor, ameloblastic fibroma and fibroodontoma, odontoma, squamous odontogenic tumor, calcifying cystic odontogenic tumor, primordial odontogenic tumor, central odontogenic fibroma, and odontogenic myxomas), and malignant tumors (clear cell odontogenic carcinoma, ameloblastic carcinoma, ameloblastic fibrosarcoma).

Transcriptome Variability in Keratocystic Odontogenic Tumor Suggests Distinct Molecular Subtypes

Keratocystic Odontogenic Tumor (KCOT) is a locally aggressive developmental cystic neoplasm thought to arise from the odontogenic epithelium. A high recurrence rate of up to 30% has been found following conservative treatment. Aggressive tumor resection can lead to the need for extensive reconstructive surgery, resulting in significant morbidity and impacting quality of life. Most research has focused on candidate-genes with a handful of studies employing whole transcriptome approaches. There is also the question of which reference tissue is most biologically-relevant. This study characterizes the transcriptome of KCOT using whole genome microarray and compare it with gene expression of different odontogenic tissues (“dentome”). Laser capture microdissection was used to isolate the neoplastic epithelial tissue in 20 cases. KCOT gene expression was compared with the “dentome” and relevant pathways were examined. Cluster analysis revealed 2 distinct molecular subtypes of KCOT. Several inflammatory pathways were activated in both subtypes. The AKT pathway was activated in one subtype while MAP kinase pathway was activated in the other. Additionally, PTCH1 expression was downregulated in both clusters suggesting involvement in KCOT tumorigenesis. In conclusion, this study provides new insights into the transcriptome of KCOT and highlights pathways that could be of diagnostic and prognostic value.

Jaw cysts diagnosed in an Italian population over a 20-year period

BACKGROUND

Cysts of the jaws (JCs) are an important topic of oral pathology, but few epidemiological data are present in the literature, in particular about the potential of recurrence. The aim of this study was to describe a case series of JCs from a single institution, evaluating the frequency, the site, the age distribution, and the percentage of recurrence of all types of JCs.

METHODS

All JCs present in the histological records of the Section of Anatomic Pathology of the University of Bologna at Bellaria Hospital from 1992 to 2012 were retrieved.

RESULTS

A total of 1136 jaws cysts were obtained, of which 1117 (98.3%) were odontogenic and 19 (1.7%) were nonodontogenic. About odontogenic cysts (OCs), the most frequent was the radicular cyst (538 cases), followed by parakeratinized keratocystic odontogenic tumor (pKOT, 193 cases) and dentigerous cyst (120 cases). Among pKOT, 21 out of 193 cases (10.89%) showed a recurrence after a mean time of 4.5 years (range, 1-12 years). During follow-up (mean 11 years, range 1-19 years), all 3 cases of botrioid cysts, 12 out of 46 cases of unicystic ameloblastoma (26.09%), 2 out of 20 cases of calcifying OCs (10%) and 2 out of 538 cases of radicular cyst (0.37%) showed a recurrence.

CONCLUSION

Our study confirms that the distribution pattern of JCs in Italy is relatively similar to other studies worldwide and emphasizes the importance of recognizing the different histological types of JCs for their potential local aggressive behavior.