The Keratocystic Odontogenic Tumor

Appearance and recurrence of odontogenic keratocysts

OBJECTIVE

The purpose of this study was to evaluate the appearance, histopathological features, and recurrence of odontogenic keratocysts (OKCs) from a large single institute registry over a 36-year period.

MATERIALS AND METHODS

A total of 226 cases of OKC were identified in 174 patients over a 36-year period in a single institute in Southwestern Finland. Histological specimens were re-evaluated. The patient's age, sex, location, recurrence, and histopathological features of the OKC were the study variables.

RESULTS

OKCs occurred more frequently in men, the mean age was 46 years, and the most frequent site was the lower jaw. Recurrence rate was 21%. Histopathologically, inflammation was present in 95% and satellite cysts in 10% of cases. In patients diagnosed with satellite cysts, OKC recurred in 50% of cases, while the corresponding figure for patients without satellite cysts was 17%.

CONCLUSIONS

Compared with the literature, patients were older and inflamed cysts were found more frequently. Satellite cysts occurred only in association with chronic inflammation. Based on the results, regular radiographic evaluation is important among patients aged 10-29 years to detect OKCs and to treat them before enlargement, infection, and inflammation. Satellite cysts should be reported and may be a sign of increased risk of OKC recurrence.

Is modified Carnoy’s solution as effective as Carnoy’s solution in terms of amount of bone necrosis and depth of penetration?

Carnoy's solution, a chemical cauterisation agent, has been indicated as one of the adjuvant treatment modalities for odontogenic keratocyst. In 2000, after the ban of chloroform many surgeons adopted the use of Modified Carnoy's solution. The purpose of this study is to compare the depth of penetration and amount of bone necrosis of Carnoy's versus Modified Carnoy's solution on the mandible of Wistar rats at different time intervals. Twenty-six male Wistar rats of six to eight weeks old, weighing approximately 150-200 grams, were allocated for this study. The predictor variables were type of solution and application time. The outcome variable was depth of penetration and amount of bone necrosis. Carnoy's solution was applied on the defect on the right side of the mandible and Modified Carnoy's solution on the left side for five minutes on eight rats, eight minutes on eight rats, and 10 minutes on eight rats. All specimens were subjected to histomorphometric analysis done using Mia image AR software. Univariate ANOVA test, and paired sample t test was done to compare the results. The depth of penetration for Carnoy's solution was more than Modified Carnoy's solution in the three different exposure times. Statistically significant results were observed at five minutes and eight minutes. The amount of bone necrosis was more in Modified Carnoy's solution. The results were not statistically significant at the three different exposure times. To conclude, when one wants to use Modified Carnoy's solution, the minimum exposure time should be 10 minutes to achieve similar results as those of Carnoy's solution.

Volumetric changes in the size of odontogenic keratocysts after decompression followed by enucleation, peripheral ostectomy, and Carnoy's solution: A retrospective study

The study aimed to retrospectively analyze the reduction pattern of odontogenic keratocysts (OKCs) after decompression, followed by enucleation (EN), peripheral ostectomy (PO), and Carnoy's solution (CS) to establish the appropriate time for inserting implants, along with assessing the long-term success of conservative treatment with adjunctive therapy. The predictable variables were the reduction pattern and the study's treatment option. The outcome variable was the volumetric changes in the size of bony defects. These changes were determined using a percentage difference and a reduction rate. They were recorded after decompression and one, three, six, twelve, and eighteen months after EN. P-values of .05 were considered significant. The study included 66 patients with 71 OKCs. Males, younger ages, and mandibular OKCs significantly predominated. The decompression significantly changed the initial volume from 135.40 ± 1.2 cm3 to 101.55 ± 0.1 cm3 with 28.6 percentage difference and 25% reduction rate. At the end of the first and third months after EN, the reduction pattern is 50.0%-75.5% of the initial volume, with no significant prediction for the direction of the reduction pattern. After 18 months, all bony defects disappeared, with no recurrences for the next 18 years. In conclusion, the reduction pattern is 75.5% of its initial volume at the end of the third month after OKC management. Therefore, within the limitations of the study, its treatment approach seems to be an option amongst other protocols that includes a view to early implant based dental rehabilitation.

Odontogenic Keratocyst: A Clinical Entity With Favorable Response to Active Decompression and Distraction Sugosteogenesis

Objective

The purpose of this study was to determine the usefulness of active decompression and distraction sugosteogenesis (ADDS) for the management of non-syndromic odontogenic keratocysts (OKC).

Materials and Methods

A retrospective case series study was designed and implemented. The study observed the Declaration of Helsinki on medical protocol and ethics and it was approved by the university's Institutional Review Board (IRB). The medical files of all patients who underwent ADDS for OKCs of the jaws at the Department of Oral and Maxillofacial Surgery of a tertiary university-affiliated medical center were reviewed. Data were collected on patient's age, gender, presenting signs and symptoms, lesion location, locularity, pre-ADDS, size of the lesion, post-ADDS, pain, days with bloody discharge and/or proteinaceous fluid inside the system's external unit, days to achieve hermetic seal, size of the lesion 2 weeks after ADDS, percentage of reduction, patient's complaints/complications, and follow-up period. Pre- and post-ADDS panoramic radiographs were reviewed for reduction parameters.

Results

Six patients, 5 males and 1 female, with an average age of 45.16 years (range 16-74 years) were studied. ADDS was performed during 4 weeks in all patients. During the therapy, the extraoral unit collected blood during 2.83 days in average. In average, after the third day, the cystic cavity started to drain a proteinaceous fluid for about 9.33 days (range 6-15 days). The average pre-ADDS Standard Lesional Area Index (SLAI) was 18.17 cm2 (range 4.40 cm2-34.58 m2) and, after 2 weeks of ADDS, the average SLAI was 5.47 cm2 (range 0.49 cm2-15.39 cm2). The average percentage of reduction, after 2 weeks, was 73.93% (range 55.49%-97.51%), which yielded an overall good reaction of OKCs to ADDS. No significant reduction of the lesions was observed from week 2 to week 4, when ADDS ceased. All lesions were enucleated after 3 months. After an average of 14 months of follow-up (12 to 17 months), no signs of recurrence have been observed.

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).

Modified Carnoy's Compared to Carnoy's Solution Is Equally Effective in Preventing Recurrence of Odontogenic Keratocysts

PURPOSE

Carnoy's solution (CS), the gold standard for adjunctive chemical cautery in treatment of odontogenic keratocysts (OKCs), has been banned for 7 years, leading to substitution with the non-chloroform containing modified Carnoy's solution (MC) without data to support its effectiveness. We performed this study to compare the earlier data with CS to the more current outcomes with MC.

METHODS

A retrospective cohort study was conducted on patients diagnosed with OKC and treated by a single surgeon (GHB) with enucleation and curettage (EC), peripheral ostectomy, and application of CS or MC. The primary predictor variables were use of CS or MC. The primary outcome variables were recurrence (yes vs. no) and time to recurrence. Secondary variables included demographics, anatomic location, and whether teeth adjacent to the lesion were extracted. Statistical analyses included chi-squared test/Fisher's exact test, Wilcoxon rank sum test, and Kaplan-Meier curves.

RESULTS

77 patients, 36 patients in the CS group and 41 in the MC group, met inclusion criteria, including at least 1 year of follow-up time. Characteristics of the groups were similar: median age 41.5 and 46, 61% and 71% male gender, 81% and 90% posterior, and 64% and 50% mandibular lesions, respectively. Overall recurrence was similar, 14.29%, with 5 (13.9%) recurrences in the CS group and 6 (14.6%) in the MC group (P = 0.92). Median time to recurrence was 24 months for both groups. Preserving adjacent teeth was associated with a significant increase in recurrence (P = 0.0036).

CONCLUSION

Based on this comparison of retrospective outcome data, we found no significant difference in recurrence rate or distribution of time to recurrence between OKCs treated with CS or MC. Aggressiveness of surgical technique is likely a predictive factor in recurrence rate. Future studies should focus on prospective studies and continuing follow-up of the MC group.

Carcinomatous Transformation of Odontogenic Keratocyst and Primary Intraosseous Carcinoma: A Systematic Review and Report of a Case

PURPOSE

To assess the prognostic findings of the carcinomatous transformation of odontogenic keratocyst (OKC).

METHODS

A systematic review of all cases of carcinomatous transformation of OKC was completed, and a case report was included.

RESULTS

A total of 679 publications were screened, and 37 cases met inclusion criteria. The mean age for patients with malignant transformation of OKC was 45.1 years. Pain (67.5%) and swelling (78.3%) were the most common symptoms. The malignant transformation occurred with increased frequency in the posterior mandible and larger lesions that span greater than 2 subunits of the involved jaw. Resection was the definitive treatment in all cases and 14 cases (46%) utilized adjuvant treatment.

CONCLUSIONS

Patient outcomes and follow-up was variable in our study such that overall survival was difficult to determine. However, overall survival in malignant transformation of odontogenic cysts of all kinds ranges from 62 to 85% and 30 to 8% for 2 and 5 years, respectively.

Protocol for management of odontogenic keratocysts considering recurrence according to treatment methods

The management of odontogenic keratocysts (OKC) remains a hotly debated topic in oral and maxillofacial surgery. Despite numerous studies and systematic reviews on treatment options, there is a lack of consensus and no accepted protocol on the management of OKC. Hence, the aim of this study was to briefly summarize all large systematic reviews in the literature on the management of OKC and formulate an evidence-based management protocol. Data from five large systematic reviews were combined to calculate the mean recurrence rate for each technique. Decompression followed by enucleation along with adjuvant methods such as application of Carnoy’s solution and peripheral ostectomy can result in very low recurrence and is an acceptable first line treatment. The surgical approach should be determined by lesion size, patient age, proximity to vital structures, accessibility, soft tissue/cortical perforation, and if the lesion is recurrent.

Conservative Management of Odontogenic Keratocyst in a Tertiary Hospital

Introduction

Odontogenic keratocysts (OKCs) are benign intraosseous odontogenic lesions that have a locally aggressive behavior and exhibit a high recurrence rate after the treatment. The most appropriate surgical approaches for the successful treatment of OKCs remain controversial.

Aim

The aim of this study was to evaluate the conservative management of OKCs by enucleation along with peripheral ostectomy and chemical cauterization in terms of recurrence rates after the surgical procedure.

Materials and Methods

A retrospective study on 36 cases of OKCs treated at the Oral and Maxillofacial Surgery Department of a tertiary hospital from 2010 to 2017 was done. The demographic, clinical, radiographic, and histologic data were collected for each patient. All cases were surgically treated by enucleation followed by peripheral ostectomy and chemical cauterization using Carnoy's solution. The teeth that were involved in the lesion were extracted. The diagnosis was confirmed with excisional biopsy and histopathology reports.

Results

Most of the OKCs were found in the mandible, except three which were present in the maxilla. A significantly higher incidence was seen in males in the age group of 21-30 years. Most of the cases (30 out of 36 cases) were accessed intraorally. Patients were followed up for up to 5 years. Recurrence of the operated OKCs was observed in five cases which were managed by enucleation with peripheral ostectomy and chemical cauterization again with good results.

Conclusion

The results suggest that proper enucleation followed by peripheral ostectomy and chemical cauterization using Carnoy's solution may be the best and optimal approach for the management of OKC.

5-Fluorouracil Is Associated With a Decreased Recurrence Risk in Odontogenic Keratocyst Management: A Retrospective Cohort Study

PURPOSE

The antimetabolite drug, 5-fluorouracil (5-FU), has been suggested as an adjunctive treatment to reduce the recurrence rates of odontogenic keratocysts (OKCs). We report on the use of 5-FU in the management of patients with OKCs as a postenucleation intracavity topical dressing.

METHODS

For this retrospective cohort study, we collected all data of sequentially treated cases presenting to the University of Toronto's hospital clinics for the management of biopsy-proven OKCs. Chart reviews were conducted to identify all patients treated with 5-FU cream, and compare them to patients treated with modified Carnoy's solution (MCS). In the treatment group, all patients were treated in an identical manner with enucleation and peripheral ostectomy followed by the application of 5% 5-FU cream for 24 hours. Preoperative and postoperative radiographs were collected to determine the time to recurrence of the disease, and the techniques were compared via a multivariate Cox regression analysis.

RESULTS

Seventy patients were found to be eligible for inclusion in this study. Of these, 34 patients were treated with 5% topical 5-FU, and 36 patients were managed with MCS. The median follow-up time in the 5-FU group was 22 months (interquartile range, 36), compared with 27 months (interquartile range, 37) for the MCS group (P = .40). No recurrences were identified in the 5-FU group, compared with 9 recurrences (25%) in patients treated with MCS. 5-FU was shown to be significantly negatively associated with time to disease resolution (P < .01).

CONCLUSIONS

Results from this study suggest that when used topically, 5-FU effectively lowers the recurrence rates of OKCs. Further large scale, case-controlled studies are being investigated at our center and are warranted to make definitive conclusions regarding the effectiveness of this novel technique when compared with conventional therapies.

Conservative management of odontogenic keratocyst with long-term 5-year follow-up: Case report and literature review

•

The World Health Organization, in the last classification of the Head and Neck tumours defined Odontogenic Keratocyst as a cyst instead of a tumor.

•

There are plenty of approaches in order to reduce the high recurrence of this lesion consisted in surgical, non-surgical and combined treatment.

•

Surgical treatment is considered, for several years as the gold standard treatment, but currently a combined therapy has become as a first choice.

Introduction

Odontogenic Keratocyst (OKC) is a benign lesion recently considered an odontogenic cyst in the present World Health Organization (WHO) classification of Head and Neck tumors (2017) mainly based on its clinical and histopathological features. Several studies, systematic reviews and meta-analyses have shown a multimodal approach to reducing the high recurrence rates inherently exhibited by this pathological condition after long-term periods of follow-up.

Presentation of case

The patient, a 67-years-old woman, was submitted to conservative surgical management of an odontogenic keratocyst. Initially this consisted of decompression and subsequent enucleation, with a long-term period of follow-up to ensure that there was no recurrence.

Discussion

Conservative surgical management is the first choice and might be considered the gold standard, but combined therapy such as marsupialization, application of Carnoy’s solution, enucleation of the remnant lesion and an extensive follow-up period would considerably reduce recurrence rates.

Conclusion

Therefore, an appropriate long-term follow-up must be done after the treatment performed in order to ensure clinical success, which in this case was described as an absence of signs of recurrent disease.

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.

Adjunctive Strategies for Benign Maxillofacial Pathology

Benign cysts and neoplasms of the maxillofacial region can vary in behavior, with some growing rapidly and resulting in destruction of surrounding structures. Despite their benign histology, many require often-morbid treatment to prevent recurrence of these lesions. Several less invasive and adjunctive medical treatments have been developed to lessen the morbidity of surgical treatment. As the molecular and genomic pathogenesis of these lesions is better understood, more directed treatments may lessen the burden for patients.

Nonsyndromic Examples of Odontogenic Keratocysts: Presentation of Interesting Cases with a Literature Review

The odontogenic keratocyst (OKC) may occur at any age. However, it mostly occurs during the second and third decades of life. Compared to other odontogenic cysts, this type occurs with a frequency of 5-15%. It is more common in the mandible region and in the male sex. Histologically, odontogenic keratocysts are characterized by the presence of an external connective tissue capsule, with keratinizing lining of the epithelium consisting of 5-8 cell layers with marked palisadisation of polarized basal cells and a corrugated parakeratin layer. The objective of this study is to present cases of odontogenic keratocysts, with reference to the latest classification and dilemmas in therapeutic doctrine. This project was realized in the form of descriptive studies, specifically in a series of cases. A collection of four individual cases was found at the Department of Oral Surgery. Due to the proper approach towards diagnosis, adequate and detailed histopathological analysis, and suitable therapeutic procedures, all cases of odontogenic keratocysts were successfully treated without complications. Enucleation of OKC, with a regular follow-up, proved to be the effective therapeutic choice for the patients described in this paper. Only in the case of recurrence would we consider other therapeutic options, primarily enucleation in combination with Carnoy's solution.

Surgical Management of Large Odontogenic Cysts of the Mandible

INTRODUCTION

Odontogenic cysts are defined as those cysts that arise from odontogenic epithelium and occur in the tooth-bearing regions of the jaws. Cystectomy, marsupialization, or decompression of odontogenic cyst are the most common treatments proposed for this pathology. The aim of this study is to retrospectively evaluate the result of decompression based on the volumetric reduction of the cystic cavity and new bone formation by cone beam computerized tomography (CBCT).

METHODS

The 16 patients affected by a large odontogenic mandibular cyst were enrolled in the study. All the patients underwent a surgical decompression of the cyst followed by the enucleation after a follow-up ranging from 6 to 9 months according to the volume's reduction and new bone formation. All the patients were evaluated with a CBCT before and after the surgical decompression to measure and analyze the percentage of reduction of the cystic volume before proceeding with the enucleation.

RESULTS

The decompression of the cyst showed a reduction of the cystic volume ranging from 38.2% to 54.4% proportionally to the treatment duration. The highest percentage of volume reduction observed was 54.4% in 1 patient followed-up for 9 months, before the surgical enucleation.

CONCLUSION

In our experience, the decompression seems to be the most suitable technique for the primary treatment of large odontogenic cyst of the jaws followed by the enucleation after 6 to 9 months. The CBCT is an objective method to evaluate the cystic volume reduction after the decompression and helps the surgeon with the surgical planning.

Cyst volume changes measured with a 3D reconstruction after decompression of a mandibular dentigerous cyst with an impacted third molar

The aim of this article is to describe a large mandibular cyst treated with decompression followed by surgical enucleation. Furthermore, we described the utility of cyst volume measurements by using a 3D reconstruction on Cone Beam Computed Tomography (CBCT). The dentigerous cyst is the most common cyst type of epithelial origin, arising from remnants of odontogenic epithelium, asymptomatic and associated with the crown of an unerupted or partially or completely impacted tooth. However, after a long duration and extension of the cyst volume it may provoke significant bone resorption, cortical expansion, tooth displacement and the vitality of neighboring teeth may be affected. The regular treatment of this lesion is enucleation and extraction of the involved tooth. Marsupialization and decompression are proposed when the volume of the cyst is well developed to release the cystic pressure and allow the bone cavity to progressively decrease in volume with the gradual apposition of bone. This report presents a large dentigerous cyst related to impacted mandibular third molar of a 21-year-old male patient. The cyst was treated successfully by decompression and later by surgical enucleation with surgical extraction of the related molar. In conclusion, the combination of decompression and surgical approach showed on the three-dimensional CBCT investigation a significant correlation between the treatment and volume reduction of the cyst. The clinical case described allows us to observe bone formation after decompression and surgical enucleation was performed with less risk on vital anatomic elements.

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.

Recent trends in the treatment of benign odontogenic tumors

PURPOSE OF REVIEW

The management of benign, locally aggressive odontogenic tumors, namely, keratocystic odontogenic tumors (KOTs) and ameloblastomas, can be challenging. The purpose of this article is to briefly summarize important features of these lesions and review recent trends in the literature regarding their treatment.

RECENT FINDINGS

Currently, KOTs are frequently treated with a conservative approach consisting of enucleation and adjuvant decompression or local microablation with peripheral ostectomies, Carnoy's solution, or cryotherapy. Conversely, ameloblastomas generally require marginal or segmental resection followed by reconstruction using local bone regeneration techniques or vascularized osteocutaneous free flaps, respectively. Bone regeneration techniques have improved with the use of autogenous progenitor cells held in place by autogenous or alloplastic scaffolding. Esthetic results for free flap reconstruction have improved with the use of inconspicuous surgical approaches utilizing intraoral or rhytidectomy incisions. Molecular markers for both neoplasms are being investigated as potential targets for chemotherapeutic agents.

SUMMARY

Excluding hamartomas (i.e., odontomas), KOTs and ameloblastomas are the most common benign odontogenic lesions. Their management is often complicated by their locally infiltrative behavior, responsible for high rates of recurrence. Simple enucleation or excision of these lesions has proven insufficient. When left untreated, these lesions are capable of causing severe disfigurement and loss of function. Knowledge regarding current best practices and potential future therapeutics is imperative to well treated and effective disease management.

Does Surgical Fragmentation of Odontogenic Keratocystic Capsule Interfere With the Recurrence Rate?

PURPOSE

We hypothesized that fragmentation of the cystic capsule during surgery would influence the recurrence rate of odontogenic keratocysts (OKCs) regardless of the treatment modality chosen.

MATERIALS AND METHODS

We reviewed, in a retrospective study, cases diagnosed as OKCs on histopathologic examination at the oral pathology department between 1991 and 2013. Fragmentation data were obtained from the records of the oral surgical department.

RESULTS

Fragmentation of the capsules of OKCs during surgery did not affect recurrence, irrespective of the chosen treatment modality. The addition of techniques such as cryotherapy lowered the risk of recurrence of OKCs (P = .013) compared with after enucleation alone. Furthermore, patients with associated nevoid basal cell carcinoma syndrome had a greater recurrence rate than that of those with no associated syndrome (P = .033).

CONCLUSIONS

Fragmentation of the cystic capsule does not play an important role in the rate of OKC recurrence. The rate of recurrence can be modified by using additional strategies such as cryotherapy.

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.

Reduction rate by decompression as a treatment of odontogenic cysts

Background

Odontogenic cysts are defined as those cysts that arise from odontogenic epithelium and occur in the tooth-bearing regions of the jaws. Cystectomy, marsupialization or decompression of odontogenic cyst are treatment approach to this pathology. The aim of this study was to evaluate the effectiveness of the decompression as the primary treatment of the cystic lesions of the jaws and them reduction rates involving different factors.

Material and Methods

23 patients with odontogenic cysts of the jaws, previously diagnosed by anatomical histopathology (follicular cysts (7) and radicular cysts (16)) underwent decompression as an initial treatment. Clinical examination and pre and post panoramic radiograph were measured and analyzed. In addition, data as gender, age, time reduction and location of the lesion were collected.

Results

Significant results were obtained in relation to the location of lesions and the reduction rate (p<0.01). In a higher initial lesion, a greater reduction rate was observed (p<0.05).

Conclusions

Decompression as an initial treatment of cystic lesions of the jaws was effective; it reduces the size of the lesions avoiding a possible damage to adjacent structures. Cystic lesions in the mandible, regardless of the area where they occur will have a higher reduction rate if it is compared with the maxilla. Similar behavior was identified in large lesions compared to smaller.

Key words:Decompression, reduction rate, cyst, maxilla, mandible.

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).

Retrospective study of 289 odontogenic tumors in a Brazilian population

Background

Odontogenic tumors (OTs) are considered important among oral lesions because of their clinicopathological heterogeneity, and variable biological behavior. This paper aims to determine the frequency and distribution of OTs, over a period of 10 years, at a public university in Northeastern Brazil and compare this data with previous reports.

Material and Methods

We reviewed all cases of OTs from oral pathology laboratory of University of Pernambuco (UPE), from 2004 to 2014. Diagnoses were re-evaluated and the tumors were classified according to the latest (2005) World Health Organization Classification of Tumors. In addition, we searched in the English-language literature retrospective studies on OTs that used the same classification.

Results

Data was obtained allowing the analysis of the tissue hemodynamics. We were able to map the vascularization of the face and it was possible to access three arteries of small diameter (0,60mm angular artery; 0,55mm greater palatine artery; 0,45mm infraorbital artery).

Conclusions

OTs are uncommon neoplasms with geographic variation. Our clinicopathological features are according to literature. In the present study, KCOT was the most frequent one, showing that the new classification of OTs altered the distribution of these lesions and possibly made KCOT the most common OT observed in diagnostic services worldwide.

Key words:Odontogenic tumors, jaw neoplasms, epidemiology, oral pathology.

Biochemical and Cytological Comparison of Keratocystic Odontogenic Tumours to Nonkeratinising Odontogenic Cysts Fluid

AIM

To evaluate the levels of albumin, prealbumin, total protein, inorganic phosphate and presence of keratinocytes in the cystic fluid for the diagnosis and appropriate treatment planning of keratocystic odontogenic tumours and other non keratinizing odontogenic cysts.

MATERIALS AND METHODS

Fifteen keratocystic odontogenic tumour and 15 controls were studied. The cystic fluid was aspirated and analysed to determine the levels of albumin, prealbumin, total protein, inorganic phosphate and the presence of keratinocytes. The data collected was statistically evaluated using Mann Whitney U-Test and Student's t-test.

RESULTS

A highly significant difference (p<0.0001) was seen when a comparison of Prealbumin, total protein, inorganic phosphate and presence of keratinocytes was made between keratocystic odontogenic tumour and non keratinizing odontogenic cysts. The presence of albumin also showed a significant difference (p<0.01).

CONCLUSION

A combined analysis of total protein, albumin, prealbumin, inorganic phosphorous and detection of epithelial squames may be used as a diagnostic adjunct in the preoperative diagnosis of keratocystic odontogenic tumour in a minimally invasive and highly accurate fashion.

Five years follow-up of a keratocyst odontogenic tumor treated by marsupialization and enucleation: A case report and literature review

Odontogenic cysts are considered as nonneoplasic benign lesions. Among the cysts, keratocyst odontogenic tumor (KCOT) is an intra-osseous tumor characterized by parakeratinized stratified squamous epithelium and a potential for aggressive, infiltrative behavior, and for the possibility to develop carcinomas in the lesion wall. Thus, the aim of this study was to describe a clinical case of KCOT in a young patient and discuss the treatment alternatives to solve this case. A 15-year-old male was referred for treatment of a giant lesion in his left side of the mandible. After the biopsy, a diagnostic of KCOT was made, and the following procedures were planned for KCOT treatment. Marsupialization was performed for lesion decompression and consequent lesion size reduction. Afterward, enucleation for complete KCOT removal was performed followed by third mandibular molar extraction. After 5 years, no signs of recurrence were observed. The treatment proposed was efficient in removing the KCOT with minimal surgical morbidity and optimal healing process, and the first and second mandibular molars were preserved with pulp vitality. In conclusion, this treatment protocol was an effective and conservative approach for the management of the KCOT, enabling the reduction of the initial lesion, the preservation of anatomical structures and teeth, allowing quicker return to function. No signs of recurrence after 5 years were observed.

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.