A review of odontogenic keratocysts and the behavior of recurrences

Treatment of benign maxillomandibular osteolytic lesions larger than 4 cm: A systematic review

OBJECTIVE

This systematic review aimed to assess the different treatments of benign maxillo-mandibular radiolucent bone lesions over 4 cm to propose a management algorithm.

STUDY DESIGN

A literature search was conducted using MEDLINE/PubMed, Scopus, Google Scholar, Virtual Health Library databases, and gray literature. Randomized or non-randomized clinical trials and case series with 10 or more patients with a minimum follow up of 1 year, published in French or English until August 2023, were included. The risk of bias was assessed for all papers included.

RESULTS

Of 1433 records identified, 22 were included in this review, reporting data from 1364 lesions. Ameloblastoma was the most common lesion (51.22%) and mandible was the most common site (81.21%). Initial conservative treatment was prevalent (71.04%). Recurrence was higher after conservative (13.8%) than after radical treatments (6.5%). Multilocularity, cortical perforation, dental element preservation were linked to a higher recurrence risk.

CONCLUSION

This study has shown importance of understanding specific characteristics and recurrence risk in benign maxillomandibular osteolytic lesions. Multidisciplinary team approval, personalized approach based on lesion type and patient are crucial. The presence of at least one risk factor could lead to therapeutic decision. Despite limitations, the study informed lesion management and provided precise recommendations.

A recurrence odontogenic keratocyst formation of mandible with distinctive features: a case report

Introduction and importance

Odontogenic keratocyst (OKC) is a distinctive form of developmental odontogenic cyst that deserves special consideration because of its specific clinical behaviour and histopathologic features. The clinical and radiographic features of OKC are indefinite; while some may be associated with pain, swelling or drainage, most of them are asymptomatic. This case reports rare radiographic and histopathological features of recurrence OKC.

Case presentation

A 47-years-old male patient presented with a main complaint of a painful mass in the oral cavity with a history of previous lesions that occurred in the posterior portion of the mandible related to extraction of impacted third molar. The oral examination revealed a swelling in the molar region of the right mandible with lingual plate expansion. The radiographic and histopathologic were consistent with the diagnosis of OKC. Consequently, the lesion was surgically removed, and no clinical or radiological recurrence was observed during the 8-month postoperative follow-up.

Clinical discussion

This case explained the clinical differences between OKC and other lesions and highlights the distinctive radiologic and microscopic features that a conflict with previous studies concerning the symptoms that may related to naevoid basal cell carcinoma syndrome, and revealed the proper treatment depending on the recurrence appearance and the treatment methods that used previously.

Conclusions

This case highlights a rare multilocular appearance of recurrent OKC in the mandible with no naevoid basal cell carcinoma syndrome related, supports the marginal resection as an effective procedure in the management of recurrent OKCs cases.

A review of oral pathology in orthodontics. Part 2: Pathology of the jaw bones

For many patients, their first full jaw imagining will be requested and reported by an orthodontist. This may lead to the discovery of unexpected pathology in the jaws. In this review article, we discuss the clinical and radiological appearance as well as the pathologic features and treatment of the more common entities of the jaws. In addition, we will discuss the less common lesions which carry important consequences for the patient. Through the identification of these lesions, appropriate referral and management can be pursued.

A 3-year follow-up clinical study on the preservation for vitality of involved tooth in jaw cysts through an innovative method

Jaw cysts commonly affect the oral and maxillofacial region, involving adjacent tooth roots. The management of these teeth, particularly regarding root canal therapy and apicoectomy, lacks consensus. This study introduces a novel treatment concept and refined surgical approach to preserve pulp viability in teeth involved in jaw cysts. The objective was to investigate the effectiveness and potential benefits of this approach over a 36-month follow-up period. A conservative management approach prioritized vitality preservation, reserving root canal treatment and apicectomy for cases with post-operative discomfort. A comprehensive follow-up of 108 involved teeth from 36 jaw cyst cases treated with the modified method was conducted. Clinical observation, X-ray imaging, cone-beam computed tomography (CBCT), and pulp vitality testing assessed changes in cyst size, tooth color, pulp vitality, root structure, and surrounding alveolar bone. After 36 months, our modified surgical approach successfully preserved tooth vitality in 84 involved teeth. Adverse symptoms in 19 teeth, such as redness, swelling, fistula, and pain, resolved with postoperative root canal therapy. Follow-up was lost for five teeth in two cases. No cyst recurrences were observed, and in 34 cases, the bone cavity gradually disappeared, restoring normal bone density during long-term follow-up. Our modified surgical method effectively preserves tooth vitality in jaw cysts. This innovative approach has the potential to improve the management of teeth involved in jaw cysts.

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.

A rare case of Odontogenic Keratocyst in the Maxillary Sinus: diagnosis and management

Odontogenic keratocyst is a benign intraosseous lesion of odontogenic origin which is characterized by its aggressive nature. It is usually present in the mandibular posterior area, although it can also be found in the maxilla, particularly in the canine region. We discuss a unique example of OKC in the maxillary sinus involving the 27&28 region. Due to comparable clinical signs, this lesion is more prone to be mistaken for other lesions of the maxillary sinus, such as sinusitis or polyps. On the other side, this benign disease has the potential to develop into Ameloblastoma or squamous cell carcinoma. A favorable prognosis thus depends on early identification, precise diagnosis, appropriate treatment, and follow-ups.

Building Automation Pipeline for Diagnostic Classification of Sporadic Odontogenic Keratocysts and Non-Keratocysts Using Whole-Slide Images

The microscopic diagnostic differentiation of odontogenic cysts from other cysts is intricate and may cause perplexity for both clinicians and pathologists. Of particular interest is the odontogenic keratocyst (OKC), a developmental cyst with unique histopathological and clinical characteristics. Nevertheless, what distinguishes this cyst is its aggressive nature and high tendency for recurrence. Clinicians encounter challenges in dealing with this frequently encountered jaw lesion, as there is no consensus on surgical treatment. Therefore, the accurate and early diagnosis of such cysts will benefit clinicians in terms of treatment management and spare subjects from the mental agony of suffering from aggressive OKCs, which impact their quality of life. The objective of this research is to develop an automated OKC diagnostic system that can function as a decision support tool for pathologists, whether they are working locally or remotely. This system will provide them with additional data and insights to enhance their decision-making abilities. This research aims to provide an automation pipeline to classify whole-slide images of OKCs and non-keratocysts (non-KCs: dentigerous and radicular cysts). OKC diagnosis and prognosis using the histopathological analysis of tissues using whole-slide images (WSIs) with a deep-learning approach is an emerging research area. WSIs have the unique advantage of magnifying tissues with high resolution without losing information. The contribution of this research is a novel, deep-learning-based, and efficient algorithm that reduces the trainable parameters and, in turn, the memory footprint. This is achieved using principal component analysis (PCA) and the ReliefF feature selection algorithm (ReliefF) in a convolutional neural network (CNN) named P-C-ReliefF. The proposed model reduces the trainable parameters compared to standard CNN, achieving 97% classification accuracy.

How reliable are follow-up studies on odontogenic keratocysts?

Follow-up studies on odontogenic keratocysts have reported widely varying recurrence rates. This raises the question of how reliable these studies are and how the results should be interpreted. The aim of this study was to critically assess the information from all follow-up studies published since 2004 against a set of criteria to determine how thorough the study was. These criteria include the exclusion of the orthokeratinized variant, exclusion of cysts associated with nevoid basal cell carcinoma syndrome, and appropriate reporting of dropouts. A search of four electronic databases covering the years 2004-2022 was performed. Only studies with a sufficient follow-up period (covering a range of 1-8 years) were included. Studies with fewer than 40 cases were excluded. Fourteen relevant studies were identified in the literature search. The vast majority of these studies had considerable shortcomings, giving rise to serious doubts about the validity of their recurrence rate results. Of note, these studies have often been included in meta-analyses that report on the best treatment options to reduce the tendency of recurrences. The results of this review strongly suggest that multicentre studies with strict protocols should be performed to advance knowledge of the presentation of recurrences, both the timing and frequency.

Sociodemographic and clinical characterization of cases of 1,103 non-syndromic and 66 syndromic odontogenic keratocyst: a Brazilian multicenter study

OBJECTIVES

This multicenter study aimed to evaluate cases of non-syndrome and syndromic odontogenic keratocyst, as well as cases of recurrence within these two groups.

METHODS

This descriptive, analytical, retrospective cross-sectional study evaluated the sex, age and presence of multiple lesions in 1,169 individuals seen at 10 Brazilian oral and maxillofacial pathology centers. Of these, 1,341 odontogenic keratocysts were analyzed regarding clinical diagnosis, size, site, imaging appearance, signs and symptoms, type of biopsy, treatment, and recurrence.

RESULTS

There was a similar distribution by sex. The median age of non-syndromic and syndromic patients was 32 and 17.5 years, respectively. The posterior mandible was the site most affected by small and large lesions in both groups and in recurrent cases. Unilocular lesions were more frequent, also in recurrent cases. Mainly small lesions showed this imaging appearance. Signs and symptoms were absent in most cases. Conservative treatment was the most frequent modality in all age groups, regardless of the patient's condition and recurrence. Recurrences were uncommon.

CONCLUSION

This study showed a higher frequency of non-syndromic keratocysts in the population. Clinicopathological features related to the involvement of multiple sites, age, and recurrence may differ between syndromic and non-syndromic cases. Furthermore, we found an association between lesion size and some clinical features and between the time interval to recurrence and the syndromic spectrum.

CLINICAL RELEVANCE

To contribute to a better understanding of the distribution and association between clinical, imaging, and sociodemographic characteristics in each spectrum of the lesion.

An Insight Into the Effect of Odontogenic Keratocysts on Surrounding Structures: Cone-Beam Computed Tomography-Based Analysis of Cases

Introduction  An odontogenic keratocyst (OKC) is a benign intraosseous lesion with potential to demonstrate aggressive and invasive behavior. The aim of this retrospective study was to analyze the imaging features of the OKC using cone-beam computed tomography (CBCT) and to evaluate the association between the internal structure of the lesion and the effect of the lesion on surrounding structures. Methods Overall, 32 CBCT scans of histopathologically diagnosed cases of OKC were analyzed retrospectively. The following variables were analyzed: anatomic location of the lesions (mandible body (right/left), ramus (right/left), mandible body+ramus (right/left), maxilla (right/left), and both jaws), the internal structure of the lesion (unilocular/multilocular), and the effect of the lesion on the surrounding anatomical structures (involvement of the inferior alveolar nerve canal (IANC), displacement of the IANC, cortical expansion, displacement of the tooth, resorption of the root, associated impacted tooth, associated missing tooth). We also looked for the association between the internal structure and the effect of the lesion on anatomic structures. Results Out of 32 cases, 29 (90.6%) cases involved the mandible alone. Statistically significant association (p-value 0.005) was present between the internal structure and mean age of presentation as well as between the internal structure and impacted tooth (p-value 0.027). The association between the internal structure and other variables was statistically not significant. Conclusions The radiographic features of OKCs can be variable, and these lesions have a considerable effect on the tooth, IANC, and cortical bone. Significant association was found between the internal structure, age, and impacted tooth. Since OKCs have a high recurrence rate, CBCT is advised for evaluating the extent and location of any cortical perforations.

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.

Clinical indications for radical resection of odontogenic keratocyst: A systematic review

The aim of this study was to identify clinico pathological indications for radical resection of odontogenic keratocysts (OKCs) in the literature and formulate clinical guidelines for the management of OKCs based on these findings. A systematic review of the literature was undertaken in September 2021 in PubMed/Medline, Scopus, Web of Science, Google Scholar, and Cochrane databases. The following MeSH Keywords terms were used in the search strategies: (odontogenic keratocyst) OR (keratocystic odontogenic tumor) OR (primordial cyst) AND (treatment) OR (Radical resection) OR (Resection of OKC) OR (Treatment methods). Eligibility criteria included publications of clinical studies on histologically confirmed OKCs which underwent radical resection. Studies with less than 5 OKCs, experimental studies, epidemiological studies, studies that included orthokeratinized odontogenic cyst, and review papers were excluded. Ten studies on OKCs reporting on segmental or marginal resections were identified and analyzed qualitatively. Of the total of 221 OKCs that underwent radical resection, 67 OKCs were primary, 30 were recurrent, and the remaining were unclear whether they were primary or recurrent. Segmental mandibulectomy was performed in 131 OKCs, marginal mandibulectomy in 87 OKCs, and 3 OKCs were treated by partial maxillectomy. The main indications for radical resection were multilocular appearance, large OKCs (> 5 cm), multiple recurrent OKCs with or without cortical perforation, and malignant transformation. In conclusion, radical resection has its place in the management of OKC. It is indicated when there is an aggressive lesion with bony perforation, involvement of the pterygoid musculature or skull base, and malignant transformation. The surgeon should aim to identify these features to manage OKC appropriately and to prevent multiple recurrences. Clinical guidelines for the management of OKCs are proposed.

Odontogenic Keratocyst Presented as Multi-Locular Radiolucency in Mandibular Canine and Premolar Region: A Case Report

An odontogenic keratocyst (OKC) was first described by Philipsen in 1956. They are benign cysts of odontogenic origin that behave aggressively and have a high recurrence rate. The present case report describes an unusual presentation of OKC as a multi-locular lesion in the anterior mandible. A 14-year-old male patient was referred to the oral maxillofacial surgery clinic in Tabuk Specialist Dental Centre by his orthodontist to evaluate a radiolucent lesion that had been identified in his lower anterior teeth during an OPG examination. The patient was medically fit and had multiple previous dental restorations. An intraoral examination revealed a small bony expansion in the cystic lesion on the buccal side. The panoramic radiograph showed well-defined multi-locular radiolucencies in the lower left canine area, despite there being no tooth resorption; however, there was a slight divergence noted between the teeth. An excisional biopsy was performed, and the subsequent histopathological examination revealed a cystic lesion diagnosed as an odontogenic keratocyst. The six-month follow-up OPG showed that the site had completely healed without any lesions recurring. OKCs can present at any age, irrespective of gender. The differential diagnosis included a lateral periodontal cyst or a radicular cyst when the tooth was not vital. In this case, the six-month follow-up OPG following surgery revealed no recurrence, although a close follow-up is recommended because of the high recurrence rate.

Effectiveness of different treatments for odontogenic keratocyst: a network meta-analysis

Odontogenic keratocysts (OKC) are benign but aggressive lesions. As there is a lack of well randomized clinical studies assessing the effectiveness of the different treatment options for OKC, a network meta-analysis (NMA) was performed to identify the best treatment option with the lowest recurrence rate. An electronic search was performed following the PRISMA guidelines to identify all clinical studies comparing treatment options against enucleation alone. The outcome variable was recurrence. The predictor variables were treatments. The eight included treatments were: enucleation with peripheral ostectomy/curettage (E + PO/curettage); enucleation with cryotherapy (E + CRYO); enucleation with/without PO followed by modified Carnoy's solution (E ± PO+MCS); enucleation with PO and with topical 5-fluorouracil (E + PO+5FU); enucleation with/without PO followed by original Carnoy's solution (E ± PO+CS); marsupialization alone (MARS); marsupialization followed by secondary enucleation with/without PO (MARS+2°E ± PO); and resection. The odds ratio was used to estimate the recurrence rate. A frequentist NMA was performed using Stata software. A total of 2989 patients in 40 studies were included. Both direct pairwise meta-analysis and NMA showed that E + 5FU+PO was significantly superior to E ± PO+MCS. However, no statistically significant difference was found between E ± PO+CS vs E + 5FU+PO, E ± PO+MCS, and resection, respectively (all very low quality evidence). The three most effective treatments in reducing the recurrence rate were E + PO+ 5FU (98.1%; very low quality evidence), resection (83.5%; very low quality evidence), and E ± PO+CS (63.8%; moderate quality evidence). The findings from this study suggest that CS remains the most effective fixative agent after enucleation and PO until proven otherwise. Additionally, 5FU appears to be an effective method with promising results that needs further research. Finally, the efficacy of MCS remains controversial; further in vivo and in vitro studies are required to determine new protocols. As this NMA included retrospective studies, the results should be interpreted with great caution (level of evidence: type III).

Expression of Matrix Metalloproteinases 7 and 9, Desmin, Alpha-Smooth Muscle Actin and Caldesmon, in Odontogenic Keratocyst Associated with NBCCS, Recurrent and Sporadic Keratocysts

Nevoid basal cell carcinoma syndrome (NBCCS) associated odontogenic keratocysts (OKCs) show more aggressive behavior and it has a higher frequency of relapse than non-syndromic OKCs. Stromal myofibroblasts (MFs), characterized by α-smooth muscle actin (αSMA), desmin and caldesmon expression, and metalloproteinases (MMPs) have an essential role in the remodeling of the extracellular matrix (ECM). The aim of the study is to analyze the immunohistochemical expression of MMP-7, MMP-9, αSMA and other new markers in the study of OKCs MFs such as desmin and caldesmon in NBCCS-associated OKCs compared to recurrent and sporadic keratocysts. Fourty 40 patients (23 M and 17 F) underwent surgery to remove the OKCs. The histological sections in paraffin were incubated with markers antibodies and a semi-quantitative score was used to evaluate the immunoreactivity. Densitometric analysis showed a very significantly increased expression of αSMA, caldesmon, MMP-7 and MMP-9 in NBCCS-OKCs compared to non-syndromic OKCs (p < 0.001). However, desmin showed a not significant increased expression in non-syndromic OKC compared to NBCCS-OKCs specimens in which desmin was slightly or not at all expressed. NBCSS-OKCs showed a greater distribution of MFs compared to the other OKCs subtypes. Further studies will be needed to evaluate whether the different expressions of these markers can be correlated to a different clinical behavior.

Orthokeratinized versus parakeratinized odontogenic keratocyst: Our institutional experience

Introduction

The odontogenic keratocyst (OKC) is quite unique among odontogenic cysts in its specific histological features and in clinical characteristics. The OKC has two variants orthokeratinized odontogenic cyst (OOC) and parakeratinized odontogenic cyst (POC), and POC is considered to be more aggressive and has a high recurrence rate. Therefore, OKC has generated considerable controversy with regard to its true nature.

Aim

The purpose of this study was to determine the differences between POC and OOC variants of odontogenic cysts on the basis of clinical as well as radiological features.

Materials and Methods

A total of 85 cases were included in the present study. There was a marked difference in the age of occurrence, sex, location and radiological presentation of both these entities.

Results

Our institutional experience suggests that POC is more common than OOC and both the variants were commonly found in males. Most of the cases of POC were found in the third decade of life and most of the cases of OOC were frequently seen in the second, fourth and fifth decades. Mandibular posterior area was frequently occurring in both variants. Left side involvement was seen in maxilla and right side in mandible in both variants. Most of the cases were clinically diagnosed as OKC.

Conclusion

The treatment and prognosis varies in both the variants of OKC, hence such epidemiological studies are helpful to ensure proper treatment for these distinct entities.

Deep Learning-Based Microscopic Diagnosis of Odontogenic Keratocysts and Non-Keratocysts in Haematoxylin and Eosin-Stained Incisional Biopsies

Background: The goal of the study was to create a histopathology image classification automation system that could identify odontogenic keratocysts in hematoxylin and eosin-stained jaw cyst sections. Methods: From 54 odontogenic keratocysts, 23 dentigerous cysts, and 20 radicular cysts, about 2657 microscopic pictures with 400× magnification were obtained. The images were annotated by a pathologist and categorized into epithelium, cystic lumen, and stroma of keratocysts and non-keratocysts. Preprocessing was performed in two steps; the first is data augmentation, as the Deep Learning techniques (DLT) improve their performance with increased data size. Secondly, the epithelial region was selected as the region of interest. Results: Four experiments were conducted using the DLT. In the first, a pre-trained VGG16 was employed to classify after-image augmentation. In the second, DenseNet-169 was implemented for image classification on the augmented images. In the third, DenseNet-169 was trained on the two-step preprocessed images. In the last experiment, two and three results were averaged to obtain an accuracy of 93% on OKC and non-OKC images. Conclusions: The proposed algorithm may fit into the automation system of OKC and non-OKC diagnosis. Utmost care was taken in the manual process of image acquisition (minimum 28–30 images/slide at 40× magnification covering the entire stretch of epithelium and stromal component). Further, there is scope to improve the accuracy rate and make it human bias free by using a whole slide imaging scanner for image acquisition from slides.

Pediatric Odontogenic and Maxillofacial Bone Pathology: A Global Analysis

BACKGROUND

Although pathology in the maxillary and mandibular bones is rare in young patients, the differential diagnosis is broad. The World Health Organization (WHO) updated its classification of maxillofacial bone pathology in 2017. Using these updated guidelines, a systematic review of common maxillofacial bone lesions in the pediatric population was performed.

METHODS

A PubMed search was conducted capturing English language articles from inception to July 2020. Thirty-one articles were identified that described the frequency of maxillofacial bone pathology. Data were extracted and organized using the WHO 2017 classification of odontogenic and maxillofacial bone tumors. Prevalence data were analyzed among diagnostic categories and geographical regions. The SAS version 9.4 was used to complete statistical analyses.

RESULTS

The articles included patients from birth to a maximum age of 14 to 19 years. The most common odontogenic cysts included radicular cyst (42.7%) and dentigerous cyst (39.0%) followed by odontogenic keratocyst (15.0%). Among odontogenic bone tumors, odontoma (49.3%) was most common followed by ameloblastoma (29.1%). The most common nonodontogenic bone tumor was fibrous dysplasia (42.4%), and the most common malignant bone tumor was osteosarcoma (75.0%). Significant variations were found by geographic region, with dentigerous cyst more common than radicular cyst, and ameloblastoma more common than odontoma in African and Asian countries (P < 0.0001).

CONCLUSIONS

This systematic review uses the WHO 2017 guidelines to classify common odontogenic and nonodontogenic maxillofacial bone lesions around the world. Pathogenesis, presentation, and available treatment options for the most common maxillofacial bone lesions are reviewed.

Podoplanin Expression in Odontogenic Keratocysts Associated or not Associated With Nevoid Basal Cell Carcinoma Syndrome

BACKGROUND

Podoplanin is a transmembrane glycoprotein expressed on various normal or neoplastic cells. Some studies have shown that podoplanin promotes the migration and invasion of tumor cells. This study evaluated a podoplanin expression in Odontogenic Keratocysts (OKs) associated or not associated with Nevoid Basal Cell Carcinoma Syndrome (NBCCS) and in Orthokeratinized Odontogenic Cysts (OOCs).

MATERIALS AND METHODS

A total of 50 lesions were obtained in this study, 28 OKs, 18 OKs associated with NBCCS, and 4 OOCs. Immunohistochemical expression of podoplanin in epithelial cells was evaluated using the following score: (a) intensity of immunostaining: (0: absent, 1: weak, 2: moderate, 3: strong, and 4: very strong) and (b) number of positively cells (0: 0%, 1: <25%, 2: 25% to 50%, 3: 50% to 75%, and 4: >75%). The final score was determined by adding the scores of a and b and ranged from 0 to 8 (0: absent, 1 to 4: weak, and 5 to 8: strong).

RESULTS

Podoplanin expression was significantly stronger in the basal layer OKs and NBCCS lesions. Further, podoplanin expression was the highest in the suprabasal layer of NBCCS lesions, followed by the suprabasal layers of OK and OOC lesions.

CONCLUSIONS

Podoplanin expression is different in lesions of different biological behaviors. Podoplanin seems to play a role in cell proliferation and migration.

Appropriate follow-up period for odontogenic keratocyst: a retrospective study

Purpose

The aim of this study was to conduct epidemiologic investigations on the pattern of the lesion and differences between treatment modalities in terms of recurrence by reviewing follow-up records to form a basis for planning patient follow-up visits.

Materials and methods

In this retrospective, single-center cohort study, 266 patients diagnosed with odontogenic keratocyst between 1993 and 2013 were included. Medical records and radiographic images were analyzed for age distribution, occurrence site and size, treatment modalities, and recurrence.

Results

The average age at first diagnosis was 33.1 years, and the male to female ratio was 1.33:1.00. The highest rate of incidence was in the third decade followed by the fourth, second, and fifth decades. The incidence in the maxilla was 34%, and 66% in the mandible. Mandibular ramus was most commonly involved. Lesions between 3 and 6 crowns were the most common, and the rate of recurrence increased with size. Enucleation after decompression had higher rate of recurrence (35.8%) than enucleation (27.1%), but there was no statistical significance.

Conclusion

The recurrence of odontogenic kerotocyst (OKC) was significantly associated with large size, multilocular form, and surgical procedure. A 10-year follow-up period is recommended to determine any recurrence of OKC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40902-021-00301-x.

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.

Surgical management of the odontogenic keratocyst: A 20-year experience

The objective of this study was to describe the authors' long-term experience with the management of odontogenic keratocysts (OKCs). All OKC cases treated at the study centre between 1999 and 2015, with a minimum of 5 years of follow-up by December 2019, were reviewed retrospectively. Operative procedures including decompression/marsupialization, enucleation (E), E+Carnoy's solution (CS), E+CS+peripheral ostectomy (PO), and resection were assessed for complete resolution, partial resolution, and recurrence rates. In the parakeratinized non-syndromic group, E+CS+PO resulted in the lowest recurrence rate among the minimally invasive procedures (4.3%), while enucleation resulted in the highest rate (60%). Regarding the other modalities, recurrence was 12.5% for decompression, 11.5% for marsupialization, 16.7% for E+CS, 26.7% for E+PO, and 0% for resection. In the syndromic group, marsupialization resulted in a significantly higher recurrence (23.1%), while E+CS+PO cases showed no recurrence. No recurrence was observed in the orthokeratinized group patients treated with marsupialization or with E+CS. Based on clinico-radiographic features and observed results, it is concluded that OKC, although having a high recurrence rate, is a benign lesion and responds well to conservative procedures in most cases. Radical procedures should be reserved for unresponsive lesions and those with extensive tissue destruction.

C, Agustín MF, André Xavier Padilha F, Neimar S, Rogério Belle DO. Multimodal Protocol for the Treatment of Odontogenic Keratocysts

Purpose:

The aim of this study is to evaluate longitudinally the effectiveness of a multimodal protocol based on decompression followed by enucleation combined with the use of liquid nitrogen under local anesthesia for the treatment of odontogenic keratocysts.

Methods:

Seven patients with a diagnosis of odontogenic keratocyst were evaluated longitudinally to clinical and histological features, and pre- and postoperative radiographs were analyzed. Data were collected on the epidemiological profile of patients and on cysts, including the presence of recurrence, duration of drainage device use, lesion site, and presence of postoperative complications.

Results:

No recurrence was observed during follow-up. Mean follow-up was 59.57 months (range, 18-96 months). No pathological fracture was observed. None of the patients had persistent paresthesia of the inferior alveolar nerve. Substantial reduction in cyst size and epithelial differentiation were observed in all patients after multimodal treatment.

Conclusion:

Based on these results, the multimodal protocol proposed here was effective in the treatment of odontogenic keratocysts by reducing lesion size, avoiding possible damage to adjacent anatomical structures, and allowing a surgical procedure with less morbidity. The longitudinal follow-up of patients showed that this treatment modality is associated with a low recurrence rate compared with alternative therapies.

Autologous bone marrow aspirate concentrate (BMAC) for treatment of keratocystic odontogenic tumour (KCOT)-a case report

Management of keratocystic odontogenic tumor (KCOT) has always remained a conundrum due to its aggressive behavior, indicating wide resection. Achieving an esthetically and functionally acceptable reconstruction remains a challenge. Herein, we present a novel and less invasive technique for the treatment of KCOT. A 55-year-old female presenting with pain in the lower jaw for the past 3 months was diagnosed with a large KCOT extending from 35 to 47 region. CT images revealed buccal and lingual cortical bone erosion. Management was done in two stages: cyst curettage and chemical cauterization, followed by application of Bone Marrow Aspirate Concentrate (BMAC) with a delay of two months, to increase the thickness of eroded cortical bone. On follow-up at one year, ossification of the defect was observed. BMAC is a cocktail of mesenchymal stromal cells, hematopoietic stem cells, fibroblasts, mononuclear cells, macrophages, endothelial cells, progenitor cells, growth factors and cytokines. BMAC cocktail provide an anti-inflammatory, anti-fibrotic, anti-apoptotic, and immunomodulatory environment. Autologous platelet rich plasma provides various growth factors (TGF-β, PDGF, EGF, HGF, NGF, IGF-1) and cytokines. Addition of PRP in BMAC cocktail enhance the regeneration of tissues, where PRP act as a functional regenerative scaffold for cell integration, proliferation, and differentiation that can expedite macroscale musculoskeletal tissue healing. Autologous BMAC with corticocancellous bone acts as an osteoconductive scaffold capable of regenerating the large bone defect created by the curettage of KCOT.

Genetic factors in the pathogenesis of ameloblastoma, dentigerous cyst and odontogenic keratocyst

Ameloblastoma (AB), dentigerous cyst (DC) and Odontogenic keratocyst (OKC) are odontogenic lesions with propensity to malignant transformation or local invasion. The molecular mechanisms of development of these lesions are not fully understood. However, some researches have reported dysregulation of tumor suppressor genes or oncogenes in these lesions. Down-regulation of P53 gene has been reported in AB, DC and OKC. Moreover, several long non-coding RNAs such as ENST00000512916 and KIAA0125 have been dysregulated in AB tissues. Single nucleotide polymorphisms within a variety of genes have been associated with certain types of odontogenic lesions. In the current review, we summarize the current data about the expression pattern of genes in these lesions and the observed association between genetic polymorphisms and development of these lesions.

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.

A clinical study of inferior alveolar nerve damage caused by Carnoy's solution used as a complementary therapeutic agent in a cystic lesion

Background

Cyst enucleation, which extracts only the tumor with the application of Carnoy’s solution (CS), has been suggested as a conservative treatment with a low recurrence rate and morbidity. However, there has been a concern that CS’s contact with inferior alveolar nerve (IAN) can cause neurons to degenerate and cause sensory dysfunction. The purpose of this retrospective cohort study aimed to investigate the neurosensory function after surgical treatment with or without the application of CS.

Methods

While controlling the effects of sex, age, follow-up period, and invasion size of the tumor, we performed the binary logistic regression analysis to examine whether or not the sensory function of the patients who were treated with CS (n = 19) for the cyst enucleation procedure was significantly different from those who were not treated with CS (n = 58) at the end of the follow-up period.

Results

The logistic regression result showed that the use of CS was not significantly related to the normalness of sensory function at the end of the follow-up period. Rather, the invasion size of the cyst was significantly associated with sensory dysfunction.

Conclusions

CS may be used for patients who are diagnosed with OKC and UAM without much fear of its impact on sensory dysfunction. However, a small number of patients who were treated with CS experienced severe sensory damage and did not recover at the end of the follow-up period, suggesting the need for further analysis of these patients.

Comprehensive orthodontic treatment of a young girl with an odontogenic keratocyst and impacted teeth in the mandible

Odontogenic keratocysts (OKCs) are one of the most aggressive cysts in the oral and maxillofacial area because of their high recurrence rate and infiltrative behavior. In growing patients with OKCs, a radical treatment approach might cause numerous complications, including the disturbance of jaw growth and loss of the involved tooth. This case report describes successful comprehensive orthodontic treatment combined with marsupialization of the cyst in a young girl who exhibited an OKC with impacted teeth. The 10-year-old girl presented with an OKC extending from the mandibular symphysis through the left mandibular body, with ectopic impaction of the mandibular left canine and first premolar, as well as congenitally missing bilateral mandibular second premolars. Interestingly, spontaneous improvement of the positions of the ectopic impacted teeth, along with a reduction in the size of the cyst, occurred during marsupialization. The sequential use of removable and fixed appliances enabled orthodontic traction of the impacted teeth. The treatment outcome was stable at 2.5 years after the end of the treatment. We speculate that comprehensive orthodontic treatment combined with marsupialization can be an effective treatment strategy for patients with OKCs, especially when they are encountered in young, growing patients with impacted teeth.

Odontogenic keratocyst and ameloblastoma: radiographic evaluation

OBJECTIVES

To describe the radiographic features of odontogenic keratocysts (OKCs) and ameloblastomas and to compare the radiographic findings between these 2 lesions.

METHODS

Radiographs of OKCs and ameloblastomas were retrospectively reviewed. Location, border, shape, association with impacted tooth, tooth displacement, root resorption, and bone expansion were evaluated. Chi-squared or Fisher's exact tests were used for statistical analysis. A p value < 0.05 was considered to indicate statistical significance.

RESULTS

One hundred OKCs and 101 ameloblastomas were reviewed. The ratios of maxilla to mandible were 1:1.4 and 1:9.1 in OKCs and ameloblastomas, respectively. All evaluated features significantly differed between OKCs and ameloblastomas (p ≤ 0.001). Most OKCs showed smooth border (60%) and unilocular shape (82%), while most ameloblastomas showed scalloped border (77.2%) and multilocular shape (68.3%). Association with impacted tooth was found in 47% of OKCs and 18.8% of ameloblastomas. Adjacent tooth displacement was found in 33.7% of OKCs and 55.8% of ameloblastomas. Root resorption was more common in ameloblastomas (66.7%) than in OKCs (7%). Bone expansion was also more common in ameloblastomas (96.3%) than in OKCs (63.6%).

CONCLUSION

A unilocular radiolucent lesion with smooth border, no adjacent tooth displacement, no root resorption and causing mild or no bone expansion is suggestive of an OKC rather than an ameloblastoma.

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.

The Changing Landscape in Treatment of Cystic Lesions of the Jaws

Objective:

Cystic lesions of the jaw are common pathologies of chronic swelling of the jaw in oral and maxillofacial regions. Different treatment modalities have been described in the literature. However, the existence and proper treatment of these cysts remains a contentious topic. The aims of this review were to discuss the complexity of various surgical treatment and as factors with potential to influence outcome treatment. Finally, a practical and a rational clinical guideline for the management of such lesions have been suggested.

Materials and Methods:

A literature search without language limitation was performed in 2018 using MEDLINE, PubMed, Scopus, and Embase. Keywords for the search included the following terms: jaws cyst, cystic lesions, odontogenic cysts, cystic tumors, pseudocysts, treatments, therapy, wound healing, bone regeneration, and teeth involved cysts. Prospective or retrospective clinical studies with a sample size of n ≥ 5 were evaluated and included in this review. The exclusion criteria were studies with unclear reporting of the treatment applied or outcome, nonhuman studies, case reports, letters, preface, comments, and cystic lesions associated to syndrome. After the full reading, 30 articles were included in the quantitative synthesis for the review. No meta-analysis could be performed due to the heterogeneity of the studies included. Clinical radiographic images were presented to illustrate the principles of some surgical treatments.

Conclusion:

Conservative surgery with primary closure defect (less than 4 cm) remains an initial approach, which reduces the morbidity of aggressive surgeries and obtains the complete bone healing before 24 months of postoperative. Marsupialization is considered as the most common option for the treatment of large cystic lesions when cases are carefully selected. Evocyst is an attractive new technique of obtaining complete bone defect healing within <3 months.

Management of mandibular odontogenic keratocyst through radical resection: Report of 35 cases

The present study reported the clinical outcomes of 35 patients with mandibular odontogenic keratocysts (OKCs) following treatment by radical resection and immediate defect reconstruction. Amongst 565 patients with OKCs that were treated between April 2003 and May 2015, 35 patients underwent segmental or marginal mandibulectomy. The use of radical resection was based on clinical and/or radiographic evidence of size, cortical perforation and subsequent soft tissue involvement, and on the history of previous recurrence of the same lesion. Recurrence, justifications of the main major factor for resection, and functional and cosmetic results of the patients following mandibular reconstruction were systematically evaluated. There were 26 OKCs in the mandibular molar-ramus region, eight in the mandibular anterior-premolar region and one in the mandibular molar-ramus and anterior-molar regions. Among the 35 patients, 20 had primary OKCs and 15 had recurrent OKCs. A total of 31 patients underwent segmental mandibulectomy, of which 28 were immediately reconstructed with a vascularized flap, whereas four patients underwent marginal mandibulectomy. The functional and cosmetic outcomes of patients were evaluated as satisfactory. The length of the follow-up period ranged from 2 to 17 years following operation (average, 5.82 years). Recurrence was identified in one patient who had been treated with marginal mandibulectomy. In conclusion, the findings from the present study suggested that radical resection may be recommended for patients with OKCs and locally aggressive features. Immediate mandibular reconstruction with a vascularized flap may be a crucial part of this aggressive treatment method that may reduce OKCs-associated morbidity.

Recurrence of odontogenic keratocysts and possible prognostic factors: Review of 455 patients

BACKGROUND

To describe epidemiological features of 565 Chinese patients with odontogenic keratocysts (OKC), to investigate possible prognostic factors related to recurrence, and to analyse features of recurrent OKC (rOKC).

MATERIAL AND METHODS

A retrospective chart review of 565 cases of OKC treated between 2003 and 2015 was undertaken. The probability of recurrence related to prognostic factors including large size, cortical perforation combined with involved teeth in the lumen of the cyst, inflammation, sites of the involved lesion, sex, and daughter cyst variables were analysed. The subsequent relapse of each OKC was compared.

RESULTS

Patients ranged in age from 7 to 81 years (mean age, 28.4 years) and, of those affected, 66.9% were male and 33.1% were female. Mandibular OKC occurred in 63.01% and 36.99% occurred in the maxilla, 80.53% of patients had non-rOKC, 10.44% rOKC, and 9.03% had multiple OKC lesions. Enucleation with preservation of the involved teeth in the cystic lesion combined with cortical perforation was statistically associated with high recurrence rate, as were daughter cysts, and multilocular lesions. The number of recurrences and the average time (in years) to relapse decreased from the first relapse of OKC to the third relapse, and the difference was significant (P<.05).

CONCLUSIONS

Preservation of the involved teeth combined with cortical perforation appeared to be a potential prognostic factor associated with high recurrence. The follow-up evaluation period for rOKC with ≥ 2 previous treatments should be shorter than for first-time rOKC. The decreasing average duration (years postoperatively) to relapse was related to the number of rOKCs, timing of relapse, and rOKC type.

Expression of keratin 15 in dentigerous cyst, odontogenic keratocyst and ameloblastoma

The etiology and pathogenesis of odontogenic lesions are poorly understood. Keratin 15 (K15) is a type I cytoskeletal protein that provides structural support to the cells and has been considered to be a stem cell marker. The aim of the present study was to evaluate the expression of K15 in the epithelial lining of dentigerous cysts (DCs), odontogenic keratocysts (OKCs) and ameloblastomas (ABs). The study included 41 samples of DCs (n=13), OKCs (n=12), and AB tissues (n=16). K15 protein expression was evaluated via immunohistochemistry and data were statistically analyzed using a Kruskal-Wallis test. K15 was expressed in the majority of the studied lesions with various distributions in the different study samples. The Kruskal-Wallis test revealed non-significant differences in the expression of K15 among the three odontogenic lesions (P=0.380). The present study confirmed the high expression of K15 in the different epithelial layers of DC, OKC and AB. This type of expression excludes the reliability of regarding K15 as a stem cell marker in DC, OKC and AB. However, K15 may reflect the abnormal differentiation of pathological epithelial cells in these lesions.

Recurrence of nonsyndromic odontogenic keratocyst after marsupialization and delayed enucleation vs. enucleation alone: a systematic review and meta-analysis

PURPOSE

This study was conducted in order to determine whether marsupialization before definitive enucleation of nonsyndromic odontogenic keratocysts (OKCs) is capable of decreasing the recurrence rate more effectively than just enucleation.

METHODS

We searched MEDLINE, Web of Science, Scopus, and Cochrane Library, until August 5th of 2017 for original studies reporting on the treatment of OKCs with and without previous marsupialization and the related recurrence rate. All records and data were independently assessed, meta-analysis was performed, and the odds ratio of recurrence was the effect measure; P value for the summary effect of < 0.05 was considered statistically significant.

RESULTS

The 748 records retrieved were reduced to 6 studies to be qualitatively assessed and 5 studies were included in the meta-analysis. The overall odds ratio of 0.57 [0.25-1.28] of the pooled values pointed that marsupialization reduced the recurrence rate in comparison to just enucleation; however, the P value showed that there is no strong evidence to support this statement.

CONCLUSIONS

Marsupialization followed by enucleation after 12 to 18 months reduces the recurrence rate, but more studies are necessary to support this statement.

Odontogenic keratocyst: imaging features of a benign lesion with an aggressive behaviour

Abstract

The latest (4th) edition of the World Health Organization (WHO) Classification of Head and Neck Tumours, published in January 2017, has reclassified keratocystic odontogenic tumour as odontogenic keratocyst. Therefore, odontogenic keratocysts (OKCs) are now considered benign cysts of odontogenic origin that account for about 10% of all odontogenic cysts. OKCs arise from the dental lamina and are characterised by a cystic space containing desquamated keratin with a uniform lining of parakeratinised squamous epithelium. The reported age distribution of OKCs is considerably wide, with a peak of incidence in the third decade of life and a slight male predominance. OKCs originate in tooth-bearing regions and the mandible is more often affected than the maxilla. In the mandible, the most common location is the posterior sextant, the angle or the ramus. Conversely, the anterior sextant and the third molar region are the most common sites of origin in the maxilla. OKCs are characterised by an aggressive behaviour with a relatively high recurrence rate, particularly when OKCs are associated with syndromes. Multiple OKCs are typically associated with the nevoid basal cell carcinoma syndrome (NBCCS), an autosomal dominant multisystemic disease. Radiological imaging, mainly computed tomography (CT) and, in selected cases, magnetic resonance imaging (MRI), plays an important role in the diagnosis and management of OKCs. Therefore, the main purpose of this pictorial review is to present the imaging appearance of OKCs underlining the specific findings of different imaging modalities and to provide key radiologic features helping the differential diagnoses from other cystic and neoplastic lesions of odontogenic origin.

Key Points

• Panoramic radiography is helpful in the preliminary assessment of OKCs.

• CT is considered the tool of choice in the evaluation of OKCs.

• MRI with DWI or DKI can help differentiate OKCs from other odontogenic lesions.

• Ameloblastoma, dentigerous and radicular cysts should be considered in the differential diagnosis.

• The presence of multiple OKCs is one of the major criteria for the diagnosis of NBCCS.