The aggressive nature of the odontogenic keratocyst: is it a benign cystic neoplasm? Part 3. Immunocytochemistry of cytokeratin and other epithelial cell markers

Comparing the characteristics of recurrent versus primary odontogenic keratocysts - A single center retrospective cohort study

The high recurrence rate of odontogenic keratocysts (OKC) entails a large number of follow-up interventions after primary surgery. This study aimed to compare recurrent with primary OKC in regard to recurrence rate, treatment modality, radiographic and clinical findings. A single center retrospective cohort study with surgically treated OKC between 2012 and 2021 was conducted. The primary predictor was recurrence type of the lesion: primary (P-OKC), first recurrence (R1-OKC) and second recurrence (R2-OKC). The primary outcome variables were recurrence and time to recurrence. 68 surgeries were identified. Recurrence was not significantly associated with recurrence type (p = 0.906) but with the method of surgery (p < 0.001). Marsupialized R1-OKC recurred earlier than marsupialized P-OKC. Diameter was significantly associated with recurrence type (p = 0.002). R1-OKC had a smaller median diameter than P-OKC and R2-OKC were smaller than R1-and P-OKC. P-OKC were associated with teeth in 79% of surgeries, R1-OKC in 61% and R2-OKC in 27% (p = 0.007). Postoperative numbness was present after 40% of surgeries and decreased to 15% at follow-up, independently of recurrence type. Time to recurrence may be shorter for recurrent marsupialized OKC. Recurrent OKC are smaller and less often associated with teeth. Postoperative numbness after OKC surgery has a good prognosis.

TGF-β Signaling in Progression of Oral Cancer

Oral cancer is a common malignancy worldwide, accounting for 1.9% to 3.5% of all malignant tumors. Transforming growth factor β (TGF-β), as one of the most important cytokines, is found to play complex and crucial roles in oral cancers. It may act in a pro-tumorigenic and tumor-suppressive manner; activities of the former include cell cycle progression inhibition, tumor microenvironment preparation, apoptosis promotion, stimulation of cancer cell invasion and metastasis, and suppression of immune surveillance. However, the triggering mechanisms of these distinct actions remain unclear. This review summarizes the molecular mechanisms of TGF-β signal transduction, focusing on oral squamous cell and salivary adenoid systemic carcinomas as well as keratocystic odontogenic tumors. Both the supporting and contrary evidence of the roles of TGF-β is discussed. Importantly, the TGF-β pathway has been the target of new drugs developed in the past decade, some having demonstrated promising therapeutic effects in clinical trials. Therefore, the achievements of TGF-β pathway-based therapeutics and their challenges are also assessed. The summarization and discussion of the updated knowledge of TGF-β signaling pathways will provide insight into the design of new strategies for oral cancer treatment, leading to an improvement in oral cancer outcomes.

"Migratory Kerato osteomyelitis" - A refractory lesion of the mandible: A pathologist's and surgeon's dilemma!!

A 62 year old female patient presented with a chief complaint of non healing extraction socket in the lower left back teeth region. She underwent extraction of 37 at a private clinic following which an ulceroinfiltrative lesion developed at operated side. Multiple biopsies from the lesion were inconclusive. Computed tomography revealed an osteolytic lesion radiologically simulating carcinoma or a chondrosarcoma. Because of persistent debilitating symptoms the patient underwent Wide local excision (WLE) with left segmental mandibulectomy. Frozen sections were negative for malignancy. All margins were free from malignancy. Lymph nodes dissected showed reactive morphology. Ziehl-Neelsen, Periodic acid-Schiff and Gram stain were all negative. The lesion continued to spread even after successful surgical intervention with adequate surgical margin. The patient was eventually lost because of severe cardiac arrest during her last surgical intervention for mandibular arch reconstruction. As the lesion migrated from one side of the mandible to the other, kept showing clinical features of inflammation of the bone and bone marrow simulating features of osteomyelitis and the continued presence of keratin histologically, we contemplated whether we could give a nomenclature to the lesion as that of "Migratory Kerato osteomyelitis of the oral cavity." This could be one of case of a lifetime where multiple consultations with oral and general pathologists failed to reach a conclusive diagnosis!

Changes in Cellular Regulatory Factors before and after Decompression of Odontogenic Keratocysts

Decompression followed by enucleation, which is one of the treatments used for odontogenic keratocysts (OKCs), is frequently used in OKC lesions of large sizes. This method offers the advantage of minimizing the possibility of sensory impairment without creating a wide-range bone defect; moreover, the recurrence rate can be significantly lower than following simple enucleation. This study aimed to assess the changes in histology and expression of proliferation markers in OKCs before and after decompression treatment. A total of 38 OKC tissue samples from 19 patients who had undergone decompression therapy were examined morphologically and immunohistochemically to observe changes in proliferative activity before and after decompression. The markers used for immunohistochemistry (IHC) staining were Bcl-2, epidermal growth factor receptor (EGFR), Ki-67, P53, PCNA, and SMO. The immunohistochemistry positivity of the 6 markers was scored by using software ImageJ, version 1.49, by quantifying the intensity and internal density of IHC-stained epithelium. The values of Bcl-2, Ki-67, P53, proliferating cell nuclear antigen (PCNA), and SMO in OKCs before and after decompression showed no significant change. No correlation between clinical shrinkage and morphologic changes or expression of proliferation and growth markers could be found. There was no statistical evidence that decompression treatment reduces potentially aggressive behavior of OKC within the epithelial cyst lining itself. This might indicate that decompression does not change the biological behavior of the epithelial cyst lining or the recurrence rate.

Management of the Odontogenic Keratocyst - Six Cases with Conservative Management Supported by Chemical and Electrochemical Cauterization

Odontogenic keratocyst (OKC) has a special mention in the field of oral and maxillofacial surgery due to its varied presentation and high recurrence rate. The presence of Bcl-2 and cytokeratin 10 along with interleukins in the basal and suprabasal layers led to the inhibition of apoptosis of the surface epithelium and hence the high rate of recurrence. We discuss six cases diagnosed as odontogenic keratocyst on biopsy that underwent surgical removal. At the time of biopsy, the contents of the cyst were drained to allow decompression, then enucleation with Carnoy's solution was performed as a secondary procedure. Based on our findings, we suggest a modification to Pogrel's protocol of decompression with a drain in place followed by enucleation.

HIF-1α is Overexpressed in Odontogenic Keratocyst Suggesting Activation of HIF-1α and NOTCH1 Signaling Pathways

Background: The odontogenic keratocyst (OKC) is an odontogenic cyst that shows aggressive and intriguing biological behavior. It is suggested that a hypoxic environment occurs in OKC, which led us to investigate the immunoexpression and location of hypoxia-inducible factor 1-alpha (HIF-1α) and other hypoxia-related proteins. Methods: Twenty cases of OKC were evaluated for the expression of Notch homolog 1 (NOTCH1), HIF-1α, disintegrin and metalloproteinase domain-containing protein 12 (ADAM-12), and heparin-binding epidermal growth factor-like growth factor (HBEGF) by immunohistochemistry and compared to eight control cases of calcifying odontogenic cystic (COC), orthokeratinized odontogenic cyst (OOC), and normal oral mucosa (OM) in basal and parabasal layers. Results: In OKC, all the proteins tested were expressed significantly higher in both basal (except for NOTCH1 and HBEGF in OOC) and suprabasal epithelial layers compared to controls. Looking at the epithelial layers within OKC, we observed an increased NOTCH1 and HIF-1α expression in parabasal layers. Conclusions: These results suggest that hypoxia occurs more intensively in OKC compared to COC, OM, and OOC. Hypoxia appeared to be stronger in parabasal layers as observed by higher HIF-1α expression in upper cells. Overexpression of NOTCH1, ADAM-12, and HBEGF in OKC was observed, which suggests that microenvironmental hypoxia could potentially regulate the expression of hypoxia-related proteins, and consequently, its clinical and biological behavior.

CD63 inhibits the cell migration and invasion ability of tongue squamous cell carcinoma

The present study evaluated the expression and potential role of CD63 in the migration and invasion of tongue squamous cell carcinoma (TSCC) cells. Immunohistochemistry (IHC) was used to investigate the association between the expression level of CD63 protein and the histological differentiation of samples from 40 patients with TSCC and four normal tongue tissue specimens. RNA interference (RNAi) and gene transfection technology were used to alter the expression of CD63 in TCA8113 cells. The stable silencing and overexpression of CD63 in the TCA8113 cell line was used to assess the impact of the CD63 expression level on the migratory and invasive abilities of TCA8113 cells in a wound healing assay and a Transwell invasion assay. The effect of CD63 on the expression of matrix metalloproteinase (MMP)-2 and −9 were evaluated by western blot analysis. The results of IHC revealed a positive association between the CD63 expression level and the histopathological differentiation of TSCC and a negative association between the CD63 expression level and lymph node metastasis in TSCC. Western blotting revealed that the expressions of MMP-2 and MMP-9 were clearly upregulated in CD63-silenced TCA8113 cells but reduced in CD63-overexpressing TCA8113 cells, compared with the control. The wound-healing speed and the number of cells invading Matrigel-coated filters were negatively associated with the CD63 expression level. In summary, the results of the present study revealed that CD63 may be an inhibitor of TSCC malignancy and lymph node metastasis and may have applications in the prediction of prognosis and gene therapy for patients of TSCC.

Management of Odontogenic Cysts by Endonasal Endoscopic Techniques: A Systematic Review and Case Series

Background

Odontogenic cysts and tumors of the maxilla may be amendable to management by endonasal endoscopic techniques, which may reduce the morbidity associated with open procedures and avoid difficult reconstruction.

Objective

To perform a systematic review that evaluates the feasibility and outcomes ofendoscopic techniques in the management of different odontogenic cysts. A case series of our experience with these minimally invasive techniques was assembled for insight into the technical aspects of these procedures.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used to identify English-language studies that reported the use of endoscopic techniques in the management of odontogenic cysts. Several medical literature data bases were searched for all occurrences in the title or abstract of the terms “odontogenic” and “endoscopic” between January 1, 1950, and October 1, 2016. Publications were evaluated for the technique used, histopathology, complications, recurrences, and the follow-up period. A case series of patients who presented to a tertiary rhinology clinic and who underwent treatment of odontogenic cysts by an endoscopic technique was included.

Results

A systematic review identified 16 case reports or series that described the use of endoscopic techniques for the treatment of odontogenic cysts, including 45 total patients. Histopathologies encountered were radicular (n = 16) and dentigerous cysts (n = 10), and keratocystic odontogenic tumor (n = 12). There were no reported recurrences or major complications for a mean follow-up of 29 months. A case series of patients in our institution identified seven patients without recurrence for a mean follow-up of 10 months.

Conclusion

Endonasal endoscopic treatment of various odontogenic cysts are described in the literature and are associated with effective treatment of these lesions for an average follow-up period of >2 years. These techniques have the potential to reduce morbidity associated with the resection of these lesions, although comparative studies would better define specific indications.

Expression of YAP/TAZ in Keratocystic Odontogenic Tumors and Its Possible Association with Proliferative Behavior

The aim of this study is to clarify whether YAP/TAZ is involved in the pathogenesis and proliferative growth of keratocystic odontogenic tumor (KCOT). The expression levels of YAP/TAZ and downstream proteins and genes in normal oral mucosa (OM) and KCOT were determined and compared by immunohistochemistry and real-time quantitative PCR. The results showed that the expression of YAP/TAZ and downstream proteins (Cyr61, CTGF) was significantly upregulated in KCOT with upregulation of Ki-67 compared to OM. Importantly, the mRNA levels of transcription factors (TEAD1, TEAD4, and RUNX2) and cell cycle related genes (CDK2, PCNA), which interact with the transcriptional coactivators YAP/TAZ, are also upregulated in the KCOT. In addition, the results from Spearman rank correlation test revealed the close relationship between YAP/TAZ and Ki-67, which was further evidenced by double-labelling immunofluorescence that revealed a synchronous distribution for YAP/TAZ with Ki-67 in KCOT samples. All the data suggested YAP/TAZ might be involved in the proliferative behavior of KCOT.

Immunohistochemical evaluation of podoplanin in odontogenic tumours & cysts using anti-human podoplanin antibody

BACKGROUND

Odontogenic Cysts & tumors originate through some aberration from the normal pattern of odontogenesis. Ameloblastoma is one of the most frequent intraosseous odontogenic tumors. However it is no longer appropriate to use the diagnosis of ameloblastoma without specifying the type. Varied-clinical entities of ameloblastoma differ in their biologic behaviour. Odontogenic cysts like dentigerous and radicular cysts are less aggressive in nature than odontogenic tumors. Recently, podoplanin commonly used as a lymphatic endothelial marker in cancers has recently been found to play a possible role in odontogenic tumorigenesis also. Therefore the purpose of this study was to immunohistochemically analyse the expression of podoplanin in ameloblastomas, KCOTs, dentigerous cysts, radicular cysts & dental follicles.

METHODS

Paraffin-embedded tissue specimens of 15 Ameloblastomas (7 follicular, 6 unicystic, 2 desmoplastic),10KCOTs, 5 dentigerous cysts, 5 radicular cysts & 5 dental follicles were immunohistochemically examined using antibody against podoplanin.

RESULTS

All ameloblastomas displayed podoplanin expression in ameloblast-like cells of the epithelial islands while the stellate-reticulum like cells exhibited no or weak immunostaining. Expression of podoplanin in KCOTs was strongly positive in the cells of the basal and suprabasal layers & odontogenic epithelial nests. Positive immunoreaction for podoplanin was observed in the inflammatory radicular cysts and inflamed dentigerous cyst only and negative or weak expression in the lining epithelium of uninflamed dentigerous cysts and dental follicles.

CONCLUSION

Our results suggest that podoplanin can be used as a potential proliferative marker to observe the aggressive behaviour of ameloblastomas and KCOTs.

Genetic Changes in Sporadic Keratocystic Odontogenic Tumors (Odontogenic Keratocysts)

Little is known about the genetic background of keratocystic odontogenic tumors (KCOT, odontogenic keratocysts). Our aim was to characterize genomic aberrations in sporadic KCOT using cDNA-expression arrays and array-comparative genomic hybridization. For cDNA-expression arrays, 10 KCOT specimens and 20 fetal tooth germs were studied. Quantitative real-time reverse-transcription/polymerase chain-reaction and immunohistochemical studies were also undertaken. Several genes were over-expressed in 12q13, including cytokeratin 6B ( KRT6B) (≈ 10-fold), epidermal growth factor receptor ERBB3 (~ 4.7-fold), and glioma-associated oncogene homologue 1 ( GLI1) (~ 5- to 12-fold). One amplicon (~ 0.7 Mega base pairs [Mbp]), covering several genes involved in the regulation of cell growth, was found in 12q13.2. Deletions were found in 3q13.1, 5p14.3, and 7q31.3, including the cell-adhesion-related gene cadherin 18 ( CDH18) and leukocyte cell adhesion molecule ( ALCAM, MEMD). Over-expressed and amplified genes in 12q13, also reported in several other tumors and cell lines, may contribute to the persistent growth characteristics of KCOT.

A Comparative Analysis of Cytokeratin 18 and 19 Expressions in Odontogenic Keratocyst, Dentigerous Cyst and Radicular Cyst with a Review of Literature

INTRODUCTION

Odontogenic cysts viz Odontogenic Keratocyst (OKC), Dentigerous Cyst (DC) and Radicular Cyst (RC) occur commonly in the oral and maxillofacial region. Cytokeratin (CK) expression studies have been done to evaluate diagnostic accuracy, role in pathogenesis, elucidate behaviour and role in treatment protocols. However, variations have been reported in the expression of CK patterns in these odontogenic cysts, which could be due to the lack of standardization of laboratory techniques. The present study has tried to shed light on CK 18 and 19 expression in odontogenic cysts and offer the brief review of previous studies on these CK.

AIM

The aim of the present study was to evaluate the intensity and expression patterns of CK 18 and 19 in OKCs, DCs and RCs.

MATERIALS AND METHODS

A total of 60 cases, 20 each of OKC, DC and RC were confirmed histologically and evaluated for immunohistochemical expression pattern and intensity of CK 18 and 19.

RESULTS

A focal and variable expression of CK 18 was observed in 25% of OKCs, 15% of DCs and 10% of RCs. CK 19 was expressed in 75% of OKCs and 100% in DCs as well as RCs.

CONCLUSION

The intensity and expression of Cytokeratin 19 was more in all three cysts compared to Cytokeratin 18.

Gorlin-Goltz Syndrome: Case report and literature review

Gorlin-Goltz syndrome (GGS) is an infrequent multisystemic disease with an autosomal dominant trait, with complete penetrance and variable expressivity, though sporadic cases have been described. This article includes a case report and an extensive review of the GGS with regard to its history, incidence, etiology, features, investigations, diagnostic criteria, keratocystic odontogenic tumor and treatment modalities.

Keratocystic Odontogenic Tumours: Etiology, Pathogenesis and Treatment Revisited

INTRODUCTION

Among the pathological entities that affect the maxillofacial region, Keratocystic odontogenic tumour has been subject to a lot of debates, controversies and speculations because of its diverse nature and high recurrence rates.

MATERIALS AND METHODS

The authors conducted a search in English literature using the following keywords; "Odontogenic keratocyst" and "Keratocystic odontogenic tumour". The aim of the paper was to review all aspects of the entity, including etiology, pathogenesis, clinical and radiological manifestations, growth potential, recurrence and treatment modalities.

CONCLUSION

The controversial nature of the pathology not withstanding, there is in general a broad consensus on treating the entity conservatively with emphasis on a long term review.

Expression of Bcl-2 and epithelial growth factor receptor proteins in keratocystic odontogenic tumor in comparison with dentigerous cyst and ameloblastoma

Background:

Keratocystic odontogenic tumor (KCOT) is a developmental odontogenic cyst on which various investigations have been focused due to its biological activities, high tendency to recur and different growth mechanisms in comparison with other cystic lesions. Previous studies have shown different biological and proliferative activities for the lining epithelium of KCOT. The aim of this study was immunohistochemical evaluation of Bcl-2 and epidermal growth factor receptor (EGFR) expression in KCOT compared with dentigerous cyst and ameloblastoma.

Materials and Methods:

Formalin-fixed and paraffin-embedded tissue sections of 16 cases of KCOT, 16 cases of dentigerous cyst and 16 cases of ameloblastoma were immunohistochemically analyzed to determine Bcl-2 and EGFR proteins’ expression. Biotin-Stereotavidin method was used. It was observed by two oral pathologists separately, and the data were analyzed by Mann–Whitney and Kruskul–Wallis. P < 0.05 was considered as significant.

Results:

Regardless of staining intensity, all cases of ameloblastoma and KCOT except dentigerous cases were positively stained for Bcl-2. Expression of Bcl-2 was higher in the peripheral layer of ameloblastoma and basal layer of KCOT. Furthermore, all cases of ameloblastoma and dentigerous cysts except KCOT samples were positively stained for EGFR. Expression of EGFR was higher in the peripheral layer of ameloblastoma and basal layer of dentigerous cysts.

Conclusion:

According to the expression of — Bcl-2 in ameloblastoma and KCOT, and no expression of EGFR in KCOT, it can be concluded that the biological activity and growth mechanisms of KCOT are different compared with other cystic lesions. However, the aggressive potential of KCOT is not as severe as that of a neoplasm such as ameloblastoma.

Disruption of Smad4 in odontoblasts and dental epithelial cells influences the phenotype of multiple keratocystic odontogenic tumors

Keratocystic odontogenic tumors (KCOTs) are cystic epithelial neoplasms with a high recurrence rate. The molecular mechanisms underlying the initiation and progression of KCOTs are still largely unknown. Previous research showed that specific ablation of Smad4 in odontoblasts and dental epithelia resulted in spontaneous KCOTs in mice, and that constitutively activated Hedgehog (Hh) signaling was detected in the cyst epithelia of both Smad4(Co/Co) OC-Cre and Smad4(Co/Co) K5-Cre mice. Here, we ablated Smad4 in mouse odontoblasts and dental epithelia and compared the sizes and numbers of KCOTs. Both the number and size of KCOTs in Smad4(Co/Co) OC-Cre mice were larger than those in Smad4(Co/Co) K5-Cre mice, suggesting that paracrine signals from root odontoblasts play a more important role than those from Hertwig's epithelial root sheath (HERS) cells.

Differential expression of TLR3 and TLR4 in keratocystic odontogenic tumor (KCOT): A comparative immunohistochemical study in primary, recurrent, and nevoid basal cell carcinoma syndrome (NBCCS)--associated lesions

BACKGROUND

Toll-like receptors (TLRs) play an essential role in the activation of innate immunity and they can promote cancer cell survival and tumor progression. It has been claimed that TLRs can somehow predict the clinical behavior in oral squamous cell carcinoma (OSCCs).

AIM

To elucidate the molecular basis underlying keratocystic odontogenic tumor (KOCTs) aggressive behavior and recurrence we carried out this immunohistochemical study on TLR3 and TLR4 expression in sporadic primary KCOTs (sp-KCOTs), sporadic recurrent KCOTs (sp-KCOTs), and NBCCS-associated KCOTs (NBCCS-KCOTs).

METHOD

40 cases of KOCTs removed from 23 men and 17 women were the sample. Paraffin-embedded blocks were processed for immunohistochemistry. Sections were incubated with TLR3 and TLR4 antibodies and immunoreactivity evaluated on a semi-quantitative score.

RESULTS

Both TLR3 and TLR4 were expressed in KCOTs epithelium, although with a different extent. TLR3 was not expressed in sp-KCOTs and sr-KCOTs, but it showed a faint staining in NBCCS-KCOTs. On the other hand, both cytoplasmic and nuclear staining for TLR4 was detected in all the 3 types of lesions; however being significantly more expressed in sr-KCOT and NBCCS-KCOTs (p < 0.0001). Our results, demonstrated an association between TLR4, but not TLR3 expression to recurrence behavior of KCOTs. In fact, TLR4 was up-regulated in sr-KCOTs and NBCCS-KCOTs but not in sp-KCOTs.

CONCLUSIONS

According these findings it seems conceivable to assume that the up-regulation of TLR4 in some KCOTs can be correlated somehow to their tendency recurrence.

Early dental epithelial transcription factors distinguish ameloblastoma from keratocystic odontogenic tumor

The aim of the study was to characterize the molecular relationship between ameloblastoma and keratocystic odontogenic tumor (KCOT) by means of a genome-wide expression analysis. Total RNA from 27 fresh tumor samples of 15 solid/multicystic intraosseous ameloblastomas and 12 sporadic KCOTs was hybridized on Affymetrix whole genome arrays. Hierarchical clustering separated ameloblastomas and KCOTs into 2 distinct groups. The gene set enrichment analysis based on 303 dental genes showed a similar separation of ameloblastomas and KCOTs. Early dental epithelial markers PITX2, MSX2, DLX2, RUNX1, and ISL1 were differentially overexpressed in ameloblastoma, indicating its dental identity. Also, PTHLH, a hormone involved in tooth eruption and invasive growth, was one of the most differentially upregulated genes in ameloblastoma. The most differentially overexpressed genes in KCOT were squamous epithelial differentiation markers SPRR1A, KRTDAP, and KRT4, as well as DSG1, a component of desmosomal cell-cell junctions. Additonally, the epithelial stem cell marker SOX2 was significantly upregulated in KCOT when compared with ameloblastoma. Taken together, the gene expression profile of ameloblastoma reflects differentiation from dental lamina toward the cap/bell stage of tooth development, as indicated by dental epithelium-specific transcription factors. In contrast, gene expression of KCOT indicates differentiation toward keratinocytes.

Immunohistochemical Analysis of Matrix Metalloproteinases-1,-9 and Tenascin in Odontogenic Lesions

Ameloblastoma (ABL) and keratocystic odontogenic tumor (KOT) are benign odontogenic tumors with local aggressive behaviors. The purpose of our study was to compare MMP-1, MMP-9 and tenascin staining patterns between “aggressive” ameloblastoma / keratocystic odontogenic tumors and “non-aggressive” radicular cysts (RC)/ dentigerous cysts (DC). Ameloblastoma, keratocystic odontogenic tumor, radicular cyst (RC) and dentigerous cyst (DC) specimens were chosen from the archives of Gazi University Faculty of Dentistry, Department of Oral Pathology, and immunohistochemically stained with MMP-1, -9 and tenascin antibodies. The immunohistochemical expressions were noted and statistically analyzed. The ABLs and KOTs showed significantly higher MMP-1 and -9 positivity than the RCs and DCs (p<0.05). The ABL and KOT basement membranes showed more continuous tenascin expression. Tenascin intensity was significantly higher in the ABLs and KOTs compared to the RCs and DCs (p<0.05). The results suggest that higher expression of MMP-1 and -9 may play an essential role in the growth and progression of these tumors. Continuous tenascin positivity may reflect strong connective tissue reaction against the invasive epithelial parts of ABLs and KOTs.

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.

Transcriptional profiles of SHH pathway genes in keratocystic odontogenic tumor and ameloblastoma

BACKGROUND

Sonic hedgehog (SHH) pathway activation has been identified as a key factor in the development of many types of tumors, including odontogenic tumors. Our study examined the expression of genes in the SHH pathway to characterize their roles in the pathogenesis of keratocystic odontogenic tumors (KOT) and ameloblastomas (AB).

METHODS

We quantified the expression of SHH, SMO, PTCH1, SUFU, GLI1, CCND1, and BCL2 genes by qPCR in a total of 23 KOT, 11 AB, and three non-neoplastic oral mucosa (NNM). We also measured the expression of proteins related to this pathway (CCND1 and BCL2) by immunohistochemistry.

RESULTS

We observed overexpression of SMO, PTCH1, GLI1, and CCND1 genes in both KOT (23/23) and AB (11/11). However, we did not detect expression of the SHH gene in 21/23 KOT and 10/11 AB tumors. Low levels of the SUFU gene were expressed in KOT (P = 0.0199) and AB (P = 0.0127) relative to the NNM. Recurrent KOT exhibited high levels of SMO (P = 0.035), PTCH1 (P = 0.048), CCND1 (P = 0.048), and BCL2 (P = 0.045) transcripts. Using immunolabeling of CCND1, we observed no statistical difference between primary and recurrent KOT (P = 0.8815), sporadic and NBCCS-KOT (P = 0.7688), and unicystic and solid AB (P = 0.7521).

CONCLUSIONS

Overexpression of upstream (PTCH1 and SMO) and downstream (GLI1, CCND1 and BCL2) genes in the SHH pathway leads to the constitutive activation of this pathway in KOT and AB and may suggest a mechanism for the development of these types of tumors.

Comparative evaluation of immunohistochemistry, histopathology and conventional radiography in differentiating periapical lesions

Background and Aim:

Periapical lesions often present differently on the radiograph resulting in a dilemma in the mind of the dentist to arrive at a final diagnosis. Although, histopathologic diagnosis has been used for confirmation of the true nature of periapical lesion, the concept of transformation of periapical granulomas containing epithelium without cystification into cyst remains controversial. The aim of this in vivo study was to evaluate the efficacy of conventional radiography and histopathology in differentiating periapical lesions in adjunct with immunohistochemical analysis.

Aim:

Periapical lesions often present differently on the radiograph resulting in a dilemma in the mind of the dentist to arrive at a final diagnosis. Although, histopathologic diagnosis has been used for confirmation of the true nature of periapical lesion, the concept of transformation of periapical granulomas containing epithelium without cystification into cyst remains controversial. The aim of this in vivo study was to evaluate the efficacy of conventional radiography and histopathology in differentiating periapical lesions in adjunct with immunohistochemical analysis.

Materials and Method:

Thirty patients having large periapical radiolucency that do not heal successfully with routine endodontic therapy in relation to either maxillary or mandibular anterior teeth were selected for the study. Intraoral periapical radiographs were obtained and provisional diagnosis of the apical areas were made. Endodontic surgery was performed to enable histopathogical investigation. The histopathological interpretation was done to arrive at a final diagnosis and selected questionable granulomas were subjected for cytokeratin (CK-14) stain.

Results:

The histopathological profile of lesions consisted of 66.66% periapical granulomas, 10% cysts, 6.67% abscess and 16.67% granulomas with cystic potential. The radiographic and histopathologic correlation was found in only 30% of these cases. Strong CK-14 expression was observed in all five cases of periapical granuloma with cystic potential.

Conclusion:

The radiographic diagnosis of periapical lesions remains inconclusive. Although histopathologic examination of periapical lesions gives true nature, the precise nature of subsets of periapical granulomas may be achieved with adjunct use of immunohistochemical markers.

Presentation of a keratocystic odontogenic tumor with agenesis: a case report

Introduction

We analyzed the etiopathogenetic, clinical, radiographic, and histopathologic aspects of keratocystic odontogenic tumors, particularly in association with dental anomalies of number, with the aim of providing useful information for their correct diagnosis, treatment, and prognosis within a multidisciplinary approach.

Case presentation

A 14-year-old Caucasian girl presented for observation of bilateral agenesis of the upper incisors, which was diagnosed by orthopantomography. Approximately one year after starting orthodontic treatment, the patient went to the emergency department because of a phlegmonous tumefaction of the lateroposterior upper left maxillary region. Diagnostic orthopantomography and axial computed tomography scan results of the facial skeleton revealed a large lesion occupying the left maxillary sinus, rhizolysis of dental elements 26 and 27, and dislocation of dental element 28. The lesion and infected sinus mucosa were removed through surgical antral-cystectomy with the Caldwell-Luc approach. Histological examination of the lesion confirmed the suspected diagnosis of keratocystic odontogenic tumor. The 12-month follow-up orthopantomography and computed tomography scan results showed good trabecular bone formation in the lesion area. The 24-month follow-up results showed optimal healing in the area of the lesion, positive pulp vitality tests for teeth 26 and 27, and good periodontal tissue healing, as verified through periodontal probing.

Conclusions

Combined with our observations from a careful review of the literature, the results of the case study suggest that keratocystic odontogenic tumor and dental agenesis probably do not develop through a common genetic cause. More likely, they are caused by related environmental factors. Management of this case required the multidisciplinary collaboration of different specializations and careful planning to devise a correct therapeutic protocol and reach a favorable prognosis.

The Use of Enucleation and Chemical Cauterization (Carnoy's) in the Management of Odontogenic Keratocyst of the Jaws

The purpose of this study was to evaluate the use of enucleation and chemical cauterization in the management of odontogenic keratocyst (OKC) of the jaw. This study involves the retrospective review of 32 patients (20 males and 12 females) with 34 biopsy proven odontogenic keratocysts. All patients received a combination of enucleation and chemical cauterization with every time freshly prepared Carnoy's solution (absolute alcohol 6 mL, chloroform 3 mL, glacial acetic acid 1 mL, ferric chloride 0.1 gm/mL). None of these patients were diagnosed with basal cell nevus syndrome. Four of these patients did not give the follow up and were not included in the study. A total of 30 biopsy proven OKC were resolved with this treatment method. Post-operative follow up consists of clinical and radiographic examination. Follow up time ranged from a minimum of 2 years to a maximum of 5 years. Mean follow up was of 2.8 years. Recurrence rate of 5.8% was observed. Hence, concluded that the combination of enucleation and chemical cauterization may offer patients improved therapy in the management of odontogenic keratocysts of the jaws.

Keratocystic Odontogenic Tumor Surgical Management: Retrospective Analysis on 77 Patients

In 2005 the WHO introduced the former odontogenic keratocyst to the category of benign odontogenic tumours. The change in terminology was based on the observation that the odontogenic keratocyst behaves as a neoplasm and not like a benign cystic lesion. The present paper is a retrospective analysis on the management of keratocystic odontogenic tumor over a period of 11 years (2001–2012) in the Department of Maxillo-Facial Surgery at the University of Rome “Sapienza”, with particular focus on the surgical choices and the relative rates of relapse. The patient population consisted of 34 females and 43 males. Administered treatment modalities consisted of enucleation in 55 cases and radical resection in 22 cases. Nineteen percent of patients who underwent enucleation suffered KCOT relapse. No relapse was observed in the radical resection group with follow-up of 3–7 years. The goals of the treatment include elimination of the pathology and decrease of potential recurrence while minimizing harm to the patient. In the Authors' experience, conservative treatment still encompasses a high rate of recurrence; otherwise, resection provides the lowest recurrence rate, yet causes the most suffering to the patient. The issue surgeons encounter is whether to choose a conservative approach, reducing the morbidity to the patient, knowing that several operations may be required to eliminate recurrence; or being more aggressive and potentially more destructive, at the same time ensuring the best condition to avoid recurrence. Other studies are needed in order to find definitive guidelines for this challenging pathology.

Identification of the involvement of LOXL4 in generation of keratocystic odontogenic tumors by RNA-Seq analysis

Keratocystic odontogenic tumors (KCOT) are benign, locally aggressive intraosseous tumors of odontogenic origin. KCOT have a higher stromal microvessel density (MVD) than dentigerous cysts (DC) and normal oral mucosa. To identify genes in the stroma of KCOT involved in tumor development and progression, RNA sequencing (RNA-Seq) was performed using samples from KCOT and primary stromal fibroblasts isolated from gingival tissues. Seven candidate genes that possess a function potentially related to KCOT progression were selected and their expression levels were confirmed by quantitative PCR, immunohistochemistry and enzyme-linked immunosorbent assay. Expression of lysyl oxidase-like 4 (LOXL4), the only candidate gene that encodes a secreted protein, was enhanced at both the mRNA and protein levels in KCOT stromal tissues and primary KCOT stromal fibroblasts compared to control tissues and primary fibroblasts (P<0.05). In vitro, high expression of LOXL4 could enhance proliferation and migration of the human umbilical vein endothelial cells (HUVECs). There was a significant, positive correlation between LOXL4 protein expression and MVD in stroma of KCOT and control tissues (r=0.882). These data suggest that abnormal expression of LOXL4 of KCOT may enhance angiogenesis in KCOT, which may help to promote the locally aggressive biological behavior of KCOT.

Matrix metalloproteinases, tissue inhibitors of metalloproteinases, and growth factors regulate the aggressiveness and proliferative activity of keratocystic odontogenic tumors

OBJECTIVE

The objective of this preliminary study was to evaluate the expression of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs) and growth factors in keratocystic odontogenic tumors (KOTs).

STUDY DESIGN

The expression of MMPs, TIMPs, growth factors, and the extracellular signal-regulated kinase (ERK) 1/2 signaling pathway were assessed by immunohistochemistry in 15 cases of KOT and 4 cases of calcifying cystic odontogenic tumor (CCOT).

RESULTS

KOT samples expressed significantly higher amounts of MMPs, TIMPs, growth factors, epidermal growth factor receptor (EGFR), and ERK compared with CCOT samples, with the exception of MMP-2 and TIMP-1.

CONCLUSIONS

MMP-9, TIMP-2, EGF and transforming growth factor α act together and likely regulate the proliferation and aggressiveness of KOT. ERK-1/2 serves as the transducer of signals generated by these proteins, which signal through the common receptor, EGFR. This process may be related to the increased proliferation and aggressiveness observed in KOT.

Keratocystic odontogenic tumor: a retrospective analysis of genetic, immunohistochemical and therapeutic features. Proposal of a multicenter clinical survey tool

OBJECTIVE

In 2005, the World Health Organization reclassified the parakeratinizing odontogenic keratocyst as a neoplasm. This article reviews the research leading to this reclassification, and validates a new survey tool that can be easily used to pool surgical and recurrence data from multiple offices.

STUDY DESIGN

All odontogenic lesions accessioned in the Iowa Surgical Oral Pathology Laboratory between 1949 and 2010 were identified from the database. A survey tool to assess treatment and follow-up was created. A total of 46 surgeons agreed to participate.

RESULTS

A total of 70 keratocystic odontogenic tumors (KOTs) had documented recurrences at follow-up intervals ranging from 6 months to 5 years. Primary tumors that recurred ranged in size as measured by greatest radiographic diameter from 0.7 to 6 cm.

CONCLUSIONS

This survey tool is recommended as standard allowing treatment of cases by multiple practitioners to be compared retrospectively or prospectively.

Detection of epidermal growth factor receptor intensity in asymptomatic fully impacted lower third molar follicles of smoking and nonsmoking patients

OBJECTIVE

The objective of this study was to determine whether smoking causes pathological changes, comparing intensity of epidermal growth factor receptor (EGFR) expression in smokers' and nonsmokers' pericoronal follicles located around asymptomatic impacted lower third molars.

STUDY DESIGN

Eighty-two dental follicles were collected from asymptomatic mandibular third molars of 41 smoker and 41 nonsmoker patients. Specimens were examined immunohistochemically using antibody against EGFR.

RESULTS

The expression of EGFR in smokers' pericoronal follicles was higher as compared with nonsmokers (P = 0.036). Also, high EGFR expression was detected in female smokers than in female nonsmokers (P = 0.01). There was a statistically significant correlation between pack-years and EGFR expression intensity in male patients.

CONCLUSIONS

The risk of pathological differentiation in pericoronal tissues of smoking patients is higher than in the nonsmoking patients. This factor may be taken into account when deciding whether to remove an asymptomatic impacted lower third molar.

Gorlin-Goltz syndrome

Gorlin-Goltz syndrome is an uncommon autosomal dominant inherited disorder, which is characterized by multiple odontogenic Keratocysts and basal cell carcinomas, skeletal, dental, ophthalmic, and neurological abnormalities, intracranial ectopic calcifications of the falx cerebri, and facial dysmorphism. Pathogenesis of the syndrome is attributed to abnormalities in the long arm of chromosome 9 (q22.3-q31) and loss or mutations of human patched gene (PTCH1 gene). Diagnosis is based upon established major and minor clinical and radiological criteria and ideally confirmed by deoxyribo nucleic acid analysis. We report a case of a 9-year-old girl presenting with three major and one minor feature of Gorlin-Goltz syndrome. Radiologic findings of the syndrome are easily identifiable on Orthopantomogram, chest X-ray, and Computed tomography scans. These investigations prompt an early verification of the disease, which is very important to prevent recurrence and better survival rates from the coexistent diseases.

Odontogenic tumours: 240 cases diagnosed over 31 years at a Brazilian university and a review of international literature

This study describes the epidemiology and clinical presentation of odontogenic tumours (OT) seen at a regional Brazilian oral and maxillofacial pathology service; to assess the quantitative impact of the most recent World Health Organization (WHO) classification of these lesions; and to compare this series with others available in international databases. The study was carried out by retrospectively analysing 240 cases diagnosed from 1978 to 2009, followed by a comprehensive review of the literature. The patients' mean age was 29 years, with a male to female ratio of 1:1.1. Benign lesions comprised 97.9% of the cases (mostly keratocystic odontogenic tumours (KCOT), odontomas and ameloblastomas) with the remaining tumours depicting a prevalence of less than 5%. Adenomatoid OT were less frequent than in most previous studies, while malignant OT were strikingly numerous. Most OT in children and in the anterior maxilla were odontomas, while maxillary ameloblastomas were rare. Lack of swelling was more frequent in KCOT than in ameloblastomas. The present study confirms the relative impact of KCOT in the epidemiology of OT and identifies more similarities between the present series with reports from the United States and Europe than with African and Asian populations.

Targeting the sonic hedgehog pathway in keratocystic odontogenic tumor

Keratocystic odontogenic tumors (KCOT) may occur sporadically or associated with the nevoid basal cell carcinoma syndrome. It is a benign aggressive tumor of odontogenic epithelial origin with a high rate of recurrence. A primary human keratocystic odontogenic tumor cell population, KCOT-1, has been established from a tumor explant culture. The KCOT-1 cells were characterized by growth rate, gene expression profiles of major tooth enamel matrix proteins (EMPs), amelogenin (AMELX), enamelin (ENAM), ameloblastin (AMBN), amelotin (AMTN), tumor-related proteins enamelysin (MMP-20), kallikrein-4 (KLK-4), and odontogenic ameloblast-associated protein (ODAM) using quantitative real-time reverse transcription-polymerase chain reaction. Cytokeratin 14 (CK14) was examined by immunohistochemistry. In addition, expression of the members of the sonic hedgehog (SHH) pathway, SHH, patched (PTCH-1), smoothened (SMO), GLI-1, and GLI-2 and of the NOTCH signaling pathway, NOTCH-1, NOTCH-2, NOTCH-3, JAG-2 (Jagged-2), and Delta-like-1 (DLL-1) were evaluated. KCOT-1 cells were treated with SMO antagonist cyclopamine. We found that cyclopamine significantly arrested the growth of KCOT-1 cells in a dose-dependent manner and that the effects of cyclopamine were abolished by adding SHH protein. The protein expression of the SHH pathway was down-regulated by cyclopamine, further confirming that cyclopamine inhibits the SHH signaling pathway; SHH down-regulation correlated with the down-regulation of the NOTCH signaling pathway as well. In conclusion, using an established KCOT-1 cell population, we characterized the gene expression profiles related to the EMPs, SHH, and NOTCH signaling pathway and confirmed that cyclopamine significantly arrested the growth of KCOT-1 cells and may be a viable agent as a novel therapeutic.

Odontogenic keratocysts/keratocystic odontogenic tumours: biological characteristics, clinical manifestation and treatment

BACKGROUND

Odontogenic keratocysts (OKCs) now reclassified as Keratocystic odontogenic tumours (KCOTs) are a clinical entity with a characteristic microscopic picture, kinetic growth and biological behaviour. They arise from the proliferation of the epithelial dental lamina in both maxilla and mandible and occur in patients of all ages. 70-80% of keratocysts are found in the mandible commonly in the angle between the jaw and mandibular branch and maxillary region of the third molar. The cysts are long latent, often symptomless and may attain remarkable dimensions without significant deformation of the jaw bones. They are often found during routine dental X-ray examination. Compared to other types of jaw cyst, odontogenic cysts have a striking tendency to rapid growth and re-occurrence.

AIMS

This review focuses on the biological characteristics, clinical behaviour and treatment of KCOTs.

METHODS

The databases searched were the PubMed interface of MEDLINE and LILACS.

RESULTS AND CONCLUSIONS

Ondontogenic keratinocysts are not currently a diagnostic problem. Orthopantomograms which are today ordinary tools of dental investigation enable diagnosis of clinically asymptomatic cystic lesions. The problem remains the optimal therapeutic approach to reduce the still high likelihood of postoperative recurrence. There is no complete consensus on the ideal operating procedure but cystectomy with delayed extirpation is favoured. An open question also remains the timeliness of screening for postoperative recurrences. Given that the first clinical manifestation of Nevoid Basal Cell Carcioma Syndome (NBCCS) may be lesions of this type, routine histopathological classification supplemented by analysis of immunophenotype should be done. Patients with proven sporadic and especially syndromic OKC should be long term screened. In patients with NBCC preventive X ray examination is recommended only once a year.

Gorlin-Goltz syndrome

Gorlin-Goltz syndrome is an autosomal dominant inherited disorder characterized by the presence of multiple odontogenic keratocysts along with various cutaneous, dental, osseous, ophthalmic, neurological, and sex organ abnormalities. Early diagnosis is essential as it may progress to aggressive basal cell carcinomas and neoplasias. Gorlin-Goltz syndrome has rarely been reported from India. We report here one such patient, diagnosed at a rural hospital.

WITHDRAWN: Comparison of Enucleation With and Without Carnoy Solution for the Treatment of Odontogenic Keratocyst: A Prospective, Randomized Clinical Trial

The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.joms.2011.01.034. The duplicate article has therefore been withdrawn.

Does a difference exist in inferior alveolar canal displacement caused by commonly encountered pathologic entities? An observational study

PURPOSE

The aim of the present study was to investigate whether a difference exists in the location of the displaced inferior alveolar canal (IAC) and neurovascular bundle (toward the buccal or lingual cortex) among odontogenic tumors and vascular lesions. If some consistency exists in the manner in which the canal and bundle are displaced on radiographic examination, the nature of the mandibular lesion under examination could be anticipated. This information would assist the surgical team in treatment planning, diagnostic biopsy, and resection, especially in cases of intraosseous vascular pathologic findings.

MATERIALS AND METHODS

A retrospective review of the computed tomography images obtained for odontogenic tumors and vascular anomalies treated at the Department of Oral and Maxillofacial Surgery, University of Illinois at Chicago, from January 2000 to June 2010 was undertaken. The IAC and neurovascular bundle were traced from the lingula to the mental foramina, and its location within the mandible was recorded at 3 specific points.

RESULTS

In the odontogenic tumor group, we found that the canal with the neurovascular bundle was displaced either toward the buccal cortex of the mandible or the inferior border, but it was never identified lingually. In contrast, all the vascular anomalies had displaced the structures toward the lingual aspect of the mandible at all selected points.

CONCLUSIONS

To our knowledge, this is the first study to have examined the potential differences in the displacement of the inferior alveolar neurovascular bundle caused by the 2 commonly encountered pathologic entities in the maxillofacial skeleton: odontogenic tumors and vascular anomalies. We identified a striking difference in the manner of the IAC and its contents that was consistent among the tumors in the 2 groups. The location of the IAC in relationship to the pathologic entity under investigation could prove valuable in the differential diagnosis and assist with planning the biopsy. Additional investigation with a larger number of cases of these 2 groups of lesions involving the mandible is warranted to confirm our preliminary findings.