Application of machine learning in the preoperative radiomic diagnosis of ameloblastoma and odontogenic keratocyst based on cone-beam CT.

OBJECTIVES: Preoperative diagnosis of oral ameloblastoma (AME) and odontogenic keratocyst (OKC) has been a challenge in dentistry. This study uses radiomics approaches and machine learning (ML) algorithms to characterize cone-beam CT (CBCT) image features for the preoperative differential diagnosis of AME and OKC and compares ML algorithms to expert radiologists to validate performance. METHODS: We retrospectively collected the data of 326 patients with AME and OKC, where all diagnoses were confirmed by histopathologic tests. A total of 348 features were selected to train six ML models for differential diagnosis by a 5-fold cross-validation. We then compared the performance of ML-based diagnoses to those of radiologists. RESULTS: Among the six ML models, XGBoost was effective in distinguishing AME and OKC in CBCT images, with its classification performance outperforming the other models. The mean precision, recall, accuracy, F1-score, and area under the curve (AUC) were 0.900, 0.807, 0.843, 0.841, and 0.872, respectively. Compared to the diagnostics by radiologists, ML-based radiomic diagnostics performed better. CONCLUSIONS: Radiomic-based ML algorithms allow CBCT images of AME and OKC to be distinguished accurately, facilitating the preoperative differential diagnosis of AME and OKC. ADVANCES IN KNOWLEDGE: ML and radiomic approaches with high-resolution CBCT images provide new insights into the differential diagnosis of AME and OKC.

What Is the 5-year Incidence of Recurrent Disease of Odontogenic Keratocysts?

PURPOSE: There is no consensus on the ideal treatment of odontogenic keratocysts (OKCs). Certain risk factors may modify the disease recurrence rate. The purpose of this study was: 1) to estimate the incidence of OKC recurrence in a statistically rigorous manner; and 2) to identify risk factors associated with OKC recurrence. METHODS: The investigators designed and implemented a retrospective cohort study and enrolled a sample derived from the population of patients presenting to the Department of Oral and Maxillofacial Surgery outpatient clinics at the University of Washington School of Dentistry and Harborview Medical Center for evaluation and management of OKCs between January 1, 2010, and December 31, 2020. Predictor variables included demographics (age, gender), radiographic characteristics (location of lesion, locularity, size, and cortical perforation), and type of operation performed (decompression + cystectomy, enucleation ± adjuvant therapy, or resection). The primary outcome variable was time to recurrent disease, defined as the time from treatment to radiographic or clinical evidence of a new lesion (recorded in months). Kaplan-Meier analysis was used to estimate median time to recurrence, and Cox proportional hazards models were used to identify covariates statistically associated with recurrent disease (P ≤ .05). RESULTS: The sample was composed of 60 subjects with 63 previously untreated lesions. Eight subjects (13%) developed a recurrent lesion during the study interval with a median time to recurrence of 31 (interquartile range, 24 to 48) months. One of the 8 recurrences occurred within 12 months of treatment and 7 of the 8 recurrences occurred more than 21 months after treatment. Based on using Kaplan-Meier analysis, the 5-year incidence of disease recurrence was estimated to be 34%. Lesions with cortical perforation were 8.3 times more likely to recur (95% confidence interval [1.7, 41.3]; P-value = .01), and multilocular lesions were 10.6 times more likely to recur (95% confidence interval [1.3, 86.9]; P-value = .03). The sample size was the limiting factor to performing regression analyses. CONCLUSIONS: Virtually every publication on OKCs to date reports frequencies of disease recurrence rather than applying appropriate survival analyses commonly used to estimate outcomes in cancer research. Failure to use the appropriate statistical analyses underestimates the risk of disease recurrence. Our study is no exception. The estimated frequency of disease recurrence during the study interval was 13% (8/60). When survival analyses are applied that account for varying months of follow-up, the incidence of disease recurrence is 34 per 100 per 5 years. We recommend the application of time-to-event analyses in the study of disease entities with the potential for recurrence.

Intraosseous Mucoepidermoid Carcinoma of the Mandible Detected as an Asymptomatic Swelling.

Intraosseous mucoepidermoid carcinoma (IMEC) is a rare neoplasm of the jawbones. Although hypotheses focused on the malignant transformation of the epithelial mucosa of odontogenic cysts or ectopic salivary gland tissue have been suggested, the etiology of the disease is still unclear. It is more frequent in middle-aged individuals, has a slight female predilection, and is more common in the mandible than in the maxilla. Cortical enlargement is the most common symptom, while some lesions are detected by coincidence on radiography. This paper reports an IMEC of the mandible of a 35-year-old female, possibly arising from the remains of an odontogenic cyst associated with an unerupted mandibular molar, which was operated in an external center 5 years ago before IMEC diagnosis.

Idiopathic bone cavity mimicking a botryoid odontogenic cyst: A rare radiographic presentation in an older adult.

OBJECTIVES: This report describes an unusual case of a multilocular idiopathic bone cavity (IBC) that presented as a botryoid odontogenic cyst situated between the mandibular lateral incisor and canine in an older adult. BACKGROUND: The IBC represents an intraosseous concavity that appears radiographically as a unilocular or multilocular radiolucent lesion found in various skeletal sites, including the jaw. Atypical cases of gnathic IBC have not been appreciated in the gerodontologic literature. MATERIALS AND METHODS: The teeth adjacent to the bony lesion had normal pulpal responses to cold. A full-thickness flap was elevated and provided a direct entry into a bony concavity, which was devoid of an epithelial lining and fluid. RESULTS: The lack of a cystic lining within the empty osseous lesion following surgical entry, concomitant with the vital pulpal status of the proximal teeth, led to a diagnosis of an IBC. The bony walls underwent curettage and copious irrigation prior to primary closure. A 10-month follow-up revealed partial evidence of osseous repair. The patient will continue to be monitored. CONCLUSION: Timely surgical intervention of central lesions of the jaws may improve clinical outcomes. Variants of the IBC should be included in the differential diagnosis of multilocular lesions, particularly in the geriatric population.

Volumetric reduction in large cystic jaw lesions postoperative enucleation: a longitudinal clinical study.

BACKGROUND: Enucleation, a surgical procedure, is commonly used to treat large jaw cysts, unicystic ameloblastomas and keratocysts. However, it remains unclear to what extent the jaw bone regenerates after enucleation. We aimed to evaluate the percentage and the survival analysis of jaw bone regeneration, in terms of cavity volume residual (CVR), in patients who underwent enucleation of large jaw cysts, unicystic ameloblastomas and keratocysts. METHODS: We collected data longitudinally from 75 patients who underwent jaw cystic lesions enucleation at the Stomatological Hospital of Xi'an Jiaotong University, between January 2015 and June 2021. All patients had both preoperative and postoperative cone-beam computed tomography (CBCT) imaging data. CBCT images were analyzed using Image J. Changes in the CVR were assessed at various follow-up time points, and the Kaplan-Meier method was utilized to evaluate the CVR over time. RESULTS: The patients had a mean age of 31.7 years (range: 5.5-72 years) with 58.66% of them being male. The postoperative CVR was 32.20% at three months, 21.10% at six months, 15.90% at 12 months, and 5.60% at 24 months. The percentage of CVR during follow-up periods for the initial size Quartile (Q)1 (212.54-1569.60 mm3) was substantially lower than those of Q2 and Q3 at and after seven months of follow-up and became statistically significant at the 12-month mark. CONCLUSION: This study demonstrates that spontaneous bone regeneration can occur after enucleation of large jaw cysts, unicystic ameloblastomas and keratocysts, even without the use of filler materials. The initial size of the lesion had a significant impact on the outcome of cystic lesion enucleation over time. To minimize the risks associated with radiation exposure and expenses, we recommend reducing the frequency of CT imaging follow-ups for patients with small initial cavity sizes (ranging from 212.54 to 1569.60 mm3).

[Application of Deep Learning in Differential Diagnosis of Ameloblastoma and Odontogenic Keratocyst Based on Panoramic Radiographs].

Objective To evaluate the accuracy of different convolutional neural networks (CNN),representative deep learning models,in the differential diagnosis of ameloblastoma and odontogenic keratocyst,and subsequently compare the diagnosis results between models and oral radiologists. Methods A total of 1000 digital panoramic radiographs were retrospectively collected from the patients with ameloblastoma (500 radiographs) or odontogenic keratocyst (500 radiographs) in the Department of Oral and Maxillofacial Radiology,Peking University School of Stomatology.Eight CNN including ResNet (18,50,101),VGG (16,19),and EfficientNet (b1,b3,b5) were selected to distinguish ameloblastoma from odontogenic keratocyst.Transfer learning was employed to train 800 panoramic radiographs in the training set through 5-fold cross validation,and 200 panoramic radiographs in the test set were used for differential diagnosis.Chi square test was performed for comparing the performance among different CNN.Furthermore,7 oral radiologists (including 2 seniors and 5 juniors) made a diagnosis on the 200 panoramic radiographs in the test set,and the diagnosis results were compared between CNN and oral radiologists. Results The eight neural network models showed the diagnostic accuracy ranging from 82.50% to 87.50%,of which EfficientNet b1 had the highest accuracy of 87.50%.There was no significant difference in the diagnostic accuracy among the CNN models (P=0.998,P=0.905).The average diagnostic accuracy of oral radiologists was (70.30±5.48)%,and there was no statistical difference in the accuracy between senior and junior oral radiologists (P=0.883).The diagnostic accuracy of CNN models was higher than that of oral radiologists (P<0.001). Conclusion Deep learning CNN can realize accurate differential diagnosis between ameloblastoma and odontogenic keratocyst with panoramic radiographs,with higher diagnostic accuracy than oral radiologists.

Prevalence of odontogenic cysts in a group of Libyan population: A retrospective study.

Background: Odontogenic cysts (OCs) are commonly encountered lesions affecting the human jaws having special clinical and radiographic features depending on cyst type. The aim of this study was to determine the prevalence of odontogenic jaw cysts in a Libyan population in Benghazi and to compare these data with previously published reports from Libyan and other geographic areas. Materials and Methods: This is a descriptive study where screening of 2189 biopsies (retrieved from the archives of The Department of Oral Pathology/University of Benghazi, Libya) was performed for the sake of recognizing the three cysts chosen for the purpose of this study. Results: : Out of the screened lesions, 276 cases (12.6%) were diagnosed as odontogenic cysts in the period from 2006 to 2019. Of those, 67.39% were inflammatory and 32.61% were developmental in nature. Radicular cysts (60.5%) were the most frequent cysts followed by dentigerous cysts (14.8%) and keratocysts (14.5%). The mean ages of the patients were 32.3, 29.7, and 33.2 years, respectively. Occurrence of the cysts was noticed more in the maxilla than in the mandible (1.3:1). The overall male-to-female ratio was 1.1:1. Conclusions: The prevalence of odontogenic cysts was similar to that reported in a previous study in Libya and other countries irrespective to WHO (2017) classification of odontogenic cysts.

[Treatment tactics for patients with retention cysts, odontogenic cysts, mucocele and other pathologies of the maxillary sinuses as preparation for a sinus lift]. / Lechebnaya taktika v otnoshenii retentsionnykh kist, odontogennykh kist, mukotsele i drugikh zabolevanii verkhnechelyustnoi pazukhi pri podgotovke k sinus-liftingu.

OBJECTIVE: The aim the studi. Differential diagnosis of retention cysts of the maxillary sinus with odontogenic cysts, acute and chronic sinusitis, aspergillosis, and mucocele in preparation for sinus-lifting surgery. MATERIAL AND METHODS: The analysis of the case histories of 265 patients aged 18-65 years of both sexes who were treated at the dental clinic «Rudenta Family¼ from 2016 to 2021 was carried out. On the basis of clinical symptoms and data of cone-beam computed tomography (CBCT), a description of the pathologies of HPV is given for the purpose of differential diagnosis and correct interdisciplinary interaction with ENT doctors for the purpose of dental implantation in the lateral parts of the upper jaw. RESULTS: In 90 (out of 265) patients (34%), a change in the condition of the maxillary sinus mucosa was detected. 18 patients (7%) for preoperative preparation were sent to the ENT department of the FSBI «CCB with polyclinic¼ of the UDP of the Russian Federation with diagnoses: chronic maxillary sinusitis of various etiologies and mucocele. In this group of patients, sinus lifting followed by dental implantation was performed 6 months after endoscopic maxillofacial surgery under the control of CBCT. Retention cyst Retention cysts of the maxillary sinus were of different sizes in 62 (23.4%) patients and, depending on the size and localization of the sinus-lifting was performed with simultaneous removal of the cyst, or without removal of the cyst. CONCLUSION: Retention cysts do not need to be removed as a preoperative preparation for sinus lifting. In the case of large sizes and difficulty in peeling the Schneider membrane, retention cysts are removed by a dental surgeon during antral augmentation as one of the stages of the operation. In such pathologies as odontogenic cyst, acute and chronic sinusitis, aspergillosis, mucocele, interdisciplinary interaction of ENT doctor and dentist is necessary. Differential diagnosis of maxillary snus pathology is carried out on the basis of clinical data and a picture of cone-beam computed tomography.

Hybrid odontogenic lesions: A systematic review of 203 cases reported in the literature.

BACKGROUND: Hybrid odontogenic lesions combine histopathological characteristics of two or more odontogenic cysts and/or tumours. The aim of this study was to evaluate the available data on hybrid odontogenic lesions (HOL) and to analyse their epidemiological/clinical features and biological behaviour. METHODS: An electronic search was done in January 2021 using multiple databases. Eligibility criteria encompassed publications with sufficient clinical and histological information to confirm the tumours' diagnoses. RESULTS: A total of 147 articles were included in this study, comprising 203 cases. Calcifying odontogenic cyst associated with odontoma (COC/OD) (37/18.2%) was the most common HOL. Females were more affected with a mean age of 24.9 years. Lesions presented as asymptomatic swellings, with a mean evolution time of 8.2 months (0.3-96), and mean tumour size of 4.8 cm (0.3-7). Radiographic aspects frequently showed radiolucent (139/68.4%) and unilocular (52/25.6%) images with well-defined limits (48/23.6%). The lesions mostly affected mandibular pre-molars (69/34%) and mandibular molars (69/34%) regions. Enucleation (89/43.8%) and surgical excision (59/29%) were the most common treatment modalities. The mean follow-up time was 33.8 months (0.5-216 months) and recurrences were observed in four cases (1.9%), all of which were central odontogenic fibroma associated with central giant cell granuloma (COF/CGCG). CONCLUSION: COC/OD is the most common HOL and recurrence is a rare event, being usually associated with the diagnosis of COF/CGCG.

Dental Screening Including Panoramic Radiograph for Gorlin-Goltz Syndrome in Patients With Multiple Basal Cell Carcinomas.

PURPOSE: To answer the following clinical research question: "Among patients with multiple basal cell carcinomas (mBCCs), can panoramic radiograph (PaR) facilitate the diagnosis of Gorlin-Goltz syndrome (GGS)?" METHODS: This retrospective study enrolled mBCCs subjects who presented to a German tertiary care center between 1 January 2015 and 31 December 2021. The primary predictor was presence of syndromic mBCCs, and the main outcomes were jaw cysts and odontogenic keratocysts (OKCs). Descriptive, bi- and multivariate statistics, diagnostic test evaluation, and number needed to screen (NNS) were computed at α = 95%. RESULTS: The sample comprised 527 mBCCs patients (36.1% females; 6.8% GGS; 5.5% OKCs; mean age, 74.5 ± 15.8 years [range, 15-102]). There was a significant association between syndromic mBCCs and jaw cysts (P < .0001; NNS = 2 [95% CI, CI, 1.1 to 1.4]). In the adjusted logistic model, PaR identified GGS via radiographic diagnosis of jaw cysts in case of 1) age ≤ 35 years, 2) ≥ 5 BCCs, and 3) ≥ 1 high-risk BCCs. Nearly every jaw cyst identified by PaR was OKCs (P = .01; 95% CI, 3.1 to 3,101.4; NNS = 1.3 [95% CI, .9 to 2]). The post hoc power was 100%. CONCLUSIONS: Dental screening with the use of PaR for mBCCs patients, especially those aged ≤35 years, or with ≥5 BCCs, or ≥1 high-risk BCCs, may be helpful in detection and identification of GGS through recognition of OKCs.

A Volumetric and Morphological Analysis of Recurrent Odontogenic Keratocysts by Semiautomatic Segmentation.

PURPOSE: The authors conducted this study to provide morphological and volumetric data of recurrent odontogenic keratocysts of the upper and lower jaw to emphasize risk factors in accordance with their radiological appearance and guide clinical decisions for jeopardized patients. METHODS: By applying the open-source software "ITK-Snap" on cone-beam computed tomography images, volumetric measurements of histopathologically diagnosed recurrent odontogenic keratocysts could be performed. For statistical investigations, descriptive statistics and independent Student t test were performed. The intraclass correlation coefficient was used to assess intra- and inter-rater reliabilities. P values P  < 0.05 were considered significant. RESULTS: Forty patients (24 male and 16 female) were included in this study. Recurrent odontogenic keratocysts had a mean maximum diameter of 28.91 mm ± 12.00 mm and a mean volume of 4.48 cm3 ±â€Š4.29 cm3. According to morphology, irregular shape (P = 0.001; P = 0.005), unclear margin (P = 0.001; P = 0.001), multilocular morphology (P = 0.001; P = 0.001), and cortical bone exceedance (P = 0.001; P = 0.007) are statistically significantly associated with a larger cyst diameter and volume. Furthermore, significant differences by diameter and volume could be shown between patients with and without iliac crest graft reconstruction (P = 0.001; P = 0.001). CONCLUSIONS: Volumetric analysis reveals that recurrent odontogenic keratocysts show large diametric and volumetric extension that leads to complex reconstruction by iliac crest grafts, adding an argument that special attention should be paid to this entity and its recurrence. in case of difficult histopathological examination, lesions with irregular shape and margin, multilocular morphology, cortical bone exceedance, and clinically visible symptoms should be considered for close morphological and volumetric clinico- radiological follow-up.

Odontogenic Keratocyst in the Masseter Muscle.

ABSTRACT: Odontogenic keratocyst (OKC) arising from purely soft tissue other than the mucosa covering the jawbone is rare. A 57- year-old Korean female patient presented with a lump on her right cheek, which had been suspected as a fibrotic mass on the buccinator muscle by the local clinic. Magnetic resonance imaging showed an ovoid mass in the buccal space just before the right ramus with an enhancing component in the marginal area, and the interior of the mass revealed a fluid signal. Histopathologically, the lesion showed the typical features of OKC and the cyst wall contained some daughter cysts and the minor salivary gland, muscle, and fat tissues. The authors report a very unique case of OKC arising in the masseter muscle.

Mandibular Buccal Bifurcation Cyst: Report of Two Cases.

Mandibular buccal bifurcation cyst is a rare inflammatory odontogenic cyst. We reported two cases who complained of painful swelling of extraoral soft tissue. Intraoral examination revealed the partially erupted mandibular first molar. Cone beam computed tomography showed a well-defined cystic lesion surrounding the first molar. Histopathologic images showed the cyst wall was infiltrated by a large number of plasma cells, neutrophils and eosinophils, and lined with a thin layer of non-keratinized stratified squamous epithelium. Finally, the two patients were diagnosed as mandibular buccal bifurcation cyst and treated with cyst enucleation and curettage.

Recurrent odontogenic keratocyst with orbital invasion.

Odontogenic keratocysts (OKCs) are aggressive lesions that have been variously classified as neoplasms or cysts according to the World Health Organisation (WHO). They can be challenging to surgically remove and the cysts can exhibit locally aggressive behaviour if incompletely excised. We describe a case of recurrent OKC invading the orbit requiring multidisciplinary approach for extended surgical excision, and review the current literature regarding this condition.

Traumatic bone cyst in the mandibular ramus - A diagnostic dilemma.

Traumatic bone cysts (TBCs) are uncommon, nonneoplastic lesions occurring more commonly in the metaphysis of the long bones and contribute to only 1% of the cysts occurring in the jaws. Seen more commonly in the mandible between the canine and third molar, their occurrence in the ramus-condyle region is very rare. The radiographic appearance of this lesion is like odontogenic keratocyst (OKC) or ameloblastoma and, therefore, extremely challenging to diagnose. Misdiagnosis often results in aggressive treatment for an otherwise innocuous entity. The purpose of this article is to encourage the surgeon to consider the possibility of a TBC when encountering asymptomatic large lytic lesions in the ramus of the mandible especially in younger individuals to avert an extensive radical surgery.

Fluorine 18 Fluorodeoxyglucose PET/CT Findings in Gorlin-Goltz Syndrome.

Online supplemental material is available for this article.

Clinical and Cone-Beam Computed Tomography Features of Orthokeratinized Odontogenic Cysts and Odontogenic Keratocysts in the Mandible.

PURPOSE: The aim of the study was to compare the clinical and cone-beam computed tomography features of orthokeratinized odontogenic cysts (OOCs) and odontogenic keratocysts (OKCs) and to fully understand features of these 2 odontogenic cysts. MATERIALS AND METHODS: This retrospective cross-sectional study included patients with mandibular OOCs and OKCs. The predictor variables included age at the time of diagnosis, sex, anatomical location of the cysts, lesion size, cortical bone expansion rate, and presence of cortical bone destruction, impacted tooth, tooth displacement, and root resorption. The outcome variable was the type of cystic lesion. A 1-way analysis of variance test was used to analyze the differences among the cases of OOCs and OKCs. The specificity and sensitivity of the radiological features were calculated to differentiate OOCs from OKCs. RESULT: The sample was composed of 12 patients with OOCs and 36 patients with OKCs. The mean ages of the patients with OOCs (30.50 ± 6.14 years) and OKCs (38.39 ± 19.44 years) were concentrated in the third decade. The cystic lesions occurring in areas II and III accounted for 66.67 and 52.78% of the OOC and OKC cases, respectively. The cortical bone expansion rate of the OOC was larger than that of the unilocular OKC (OOC, 2.20 ± 1.05; OKC, 1.48 ± 0.50; P < .05). The specificity and sensitivity of unilocular or multiocular cysts to differentiate OOC from OKC were 100%, 42%, 95% confidence interval of 0.1479 to 0.3892 (P < .05) and tooth displacement were 100%, 3%, 95% confidence interval of 0.1479 to 0.3892 (P < .05). CONCLUSIONS: The results of this study suggest clinical and radiological features of OOCs and OKCs mostly overlap, but OOC has distinctive characteristics. Most cystic lesions of OOC are unilocular cysts, rarely accompanied by tooth displacement. The cortical bone expansion rate is larger than that of unilocular cysts of OKC.

Glandular Odontogenic Cyst-A Case Series.

The glandular odontogenic cyst (GOC) is an uncommon jawbone cyst with a challenging diagnosis because of the presence of several clinical and histopathologic overlaps with other odontogenic lesions and central mucoepidermoid carcinoma. To date, less than 200 cases of GOC have been published in the literature with reliable clinical and histopathologic information. Furthermore, the lack of a well-documented GOC case series impairs a more detailed understanding about the biological behavior and appropriate management of the lesion. Therefore, in this study, we report 3 well-documented cases of GOC in the literature. In one of the cases, the incisional biopsy was misdiagnosed as a dentigerous cyst, and the lesion recurred. Therefore, we also discuss key points regarding the diagnosis and treatment of GOC.

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.

"Looks Can be Deceptive" - Radicular Cyst Mimicking a Developmental Origin Cyst.

ABSTRACT: Cysts of the jaws are not rare, among them the radicular cyst being the most common. It is an inflammatory type of odontogenic cyst forming as a consequence of a long-standing sequel of pulpal necrosis. In contrast to its usual location of occurrence (ie, the maxilla), herewith we report a case of successful management of a 45 year old female patient with a large radiolucent lesion in the left mandibular posterior region with a mandibular ramus extension. The pathology which was strongly presenting as a developmental variety of odontogenic cyst radiographically, was diagnosed as a radicular cyst after histopathological confirmation. To the authors best of knowledge radicular cyst extending into the mandibular ramus is extremely rare and has never been reported previously.