Mandibular symmetry on posterior-anterior cephalograms of neurofibromatosis type 1 patients with facial plexiform neurofibroma.

Introduction: Neurofibromatosis type 1 (NF1) is an is an autosomal dominant heritable tumor predisposition syndrome.. Peripheral nerve sheath tumors (PNST) are a hallmark of NF1. Plexiform neurofibromas (PNF) are neoplasms that are characteristic of NF1, often causing disfiguring effects (e.g., on the face), and are considered precancerous lesions. Previous studies have shown that facial PNF (FPNF) have an impact on the shape of facial bones. This study examines deviations of mandibular symmetry from cephalometric reference planes considering the topography of FPNF. Material and methods: The posterior-anterior (PA) cephalograms of 168 patients with NF1 were examined. We compared three groups: patients with FPNF (n=74), with disseminated cutaneous neurofibroma (DNF (n=94)), and control subjects without NF1 (n=23). The PNF group was subtyped with respect to facial PNST type and location. Typical mandibular cephalometric reference points were determined (condyle, antegonion, and menton). Results: The skeletal measurement points of the mandible in FPNF patients often differ significantly from those of the DNF group. It has been proven that typical asymmetries of the median-sagittal measurement points are indicators of PNF. Differences within the trigeminal tumor spread patterns are indicated in the measured values. A local tumor effect (PNF) on the relation of the measurement points to the reference planes is made plausible by the study results. The investigations prove that tumor type (FPNF) and the number of FPNF affected branches of the trigeminal nerve may correlate with significant deviations of mandible from symmetry on PA projections. Conclusion: The presented study shows that characteristic patterns of mandibular deformity can be measured on standardized radiographs in NF1 patients with FPNF. Mandibular deformities imaged on standardized radiographs may be initial indicators of a previously unrecognized NF1. Tumor-associated alterations of the mandible should be considered in the classification systems of pathognomonic, diagnostically pioneering osseous findings in NF1. The radiological findings provide clues for planning mandibular osteotomies in NF1 patients, especially for assessing facial regions typically highly vascularized by tumor spread. Furthermore, the radiological findings are an indication of a tumor potentially invading and destroying adjacent masticatory and mimic muscle, findings that may have an influence on surgical measures (function, aesthetics, and wound healing).

Posterior-Anterior Cephalometric Study of Neurofibromatosis Type 1 Patients With Facial Plexiform Neurofibroma: Analysis of Skeletal Symmetry Concerning Midfacial and Skull Base Reference Points (Zygomatic Arch, Mastoid, and Juga).

BACKGROUND/AIM: Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome that is also characterized by skeletal abnormalities. In the cranial region, skeletal dysplasia is observed that is associated with a characteristic peripheral nerve sheath tumor, the plexiform neurofibroma (PNF). The aim of the study was to determine PNF-associated skeletal asymmetries of the mid-skull and skull base as an indicator of local tumor development. PATIENTS AND METHODS: The distances of the zygomatic arch, mastoid, and juga measurement points from the interorbital horizontal plane and median sagittal plane were examined on anterior-posterior cephalograms of 168 NF1 patients (females: 82, males: 86) and compared with the findings of a control group. A distinction was made as to whether the patients had developed a facial PNF. RESULTS: The distances of the measurement points from the reference planes differed between the patient and control group (p<0.05). Within the NF1 patients, differences between certain distances were noted when comparing patients with PNF and without PNF (p<0.05). In PNF patients, discrete changes in the skull contour were also detectable on the non-affected side (p<0.05). The caudal measurement point of the skull base showed no changes in the group comparison. CONCLUSION: The individually very variable facial PNF in NF1 is associated with deformations and misalignments of midfacial bones that follow a pattern quantifiable with cephalometric analysis.

Sequential Loss of Mandibular Permanent Incisors in Noonan Syndrome.

BACKGROUND: Noonan syndrome (NS) is a multigenic disorder with a highly variable phenotype. Cardiac disorders and a predisposition to neoplasm often require early medical attention. Central giant central lesions (CGCLs) of the jaws are part of the phenotype. CASE REPORT: In a patient with genetically confirmed NS and multiple teeth loss presumably caused by CGCL, careful review of the medical history and radiographic findings made it probable that the cause of tooth loss was cervical root resorption (CRR) of the teeth following long-term orthodontic therapy. CONCLUSION: CRR is a rare dental disease of unknown origin. However, association with prior orthodontic therapy is well documented. In NS, mandibular lesions can occur which, at first glance, might lead the examiner to assume that it is a CGCL, but on closer analysis, obviously are of non-tumorous origin and should be assessed as coincidental. The report adds relevant information to orthodontic treatment of NS patients.

A Posterior-Anterior Cephalometric Study of Skull Symmetry in Patients With Neurofibromatosis Type 1.

BACKGROUND/AIM: Neurofibromatosis type 1 (NF1) is a tumor predisposition syndrome. Bone findings make a significant contribution to the clinical diagnosis of NF1. It has been suggested that there are characteristic skeletal features of the NF1 patients' skull that cause a specific 'NF1 facies'. To test this thesis, skull examinations were carried out on NF1 patients. PATIENTS AND METHODS: The posteroanterior (PA) cephalograms of 76 patients with NF1 were analyzed using defined measuring points. Patients with confirmed facial plexiform neurofibromas (PNF) were excluded from the study. A special interest of the investigation was the symmetry of the measuring points defined as the distance to the median sagittal plane. RESULTS: NF1 patients have a slightly larger distance to the Z-plane than controls at the zygomatic arch and mastoid measurement points (p=0.027 and 0.028, respectively). In contrast, the distances of the juga and antegonion measurement points from the horizontal reference plane are larger in the control group (p=0.002 and 0.480, respectively). The transverse development of the midface at the level of the zygomatic arch showed no differences from the control group (p=0.841). The transverse diameter of the skull at the mastoid and juga measurement points is smaller in the NF1 group compared to the control group (p=0.010 and 0.002, respectively). There is a statistically significant left-right (LR) asymmetry of the distances to the median sagittal plane in favor of the left side in the patient group (p=0.002 to 0.037). However, the numerical deviations from the control group are small overall. CONCLUSION: Considering the natural, biological deviations of cephalometric measurements of the individual from idealized geometric norms, the facial skeleton of NF1 patients is symmetrically developed. It is unlikely that the calculated LR asymmetry of the patients has a visible effect. In comparison to cephalometric values of a normal population, no characteristic facial skeleton of the NF1 patient in the PA projection of the skull can be derived from these findings. Clear asymmetries of the facial skeleton should give rise to further diagnosis to clarify the suspicion of facial PNF.

Relationships of Reference Points, Planes and Skull Symmetry on Posterior-anterior Cephalograms in Healthy Young Adults.

BACKGROUND: Radiological cephalometry is an important diagnostic tool for analyzing the shape and proportions of the skull. Standardized teleradiography of the skull in posterior-anterior (PA) projection provides orientation data on the symmetry and vertical relations of the skull. The comparison of individual findings with normal values places high demands on the selection of a control group. The aim of this study was to characterize a group to be used as a standard for cephalometric comparisons. PATIENTS AND METHODS: PA teleradiographs of 23 healthy young adults were analyzed. Distances from reference measuring points to the median sagittal plane and the orbital horizontal plane were made. All individuals showed ideal occlusion. None of the participants had been subjected to orthodontic therapy or craniomaxillofacial surgery. RESULTS: The measurement results showed a high degree of lateral symmetry of the skeletal reference points and planes. Comparison of the vertical reference lines confirmed the symmetrical constitution of the facial skeleton. CONCLUSION: The study group is suitable for comparison with the cephalometric evaluations of other study groups.

Microdont Developing Outside the Alveolar Process and Within Oral Diffuse and Plexiform Neurofibroma in Neurofibromatosis Type 1.

BACKGROUND/AIM: Numerical aberrations of permanent dentition and dystopic tooth eruption are part of the phenotype of the tumor predisposition syndrome neurofibromatosis type 1 (NF1). In these cases, surplus tooth germs usually develop in the alveolar processes of the jaw. This report attests to the dystopic development of a dysplastic supernumerary tooth in NF1 arising outside the jaw. CASE REPORT: The 8-year-old male patient developed a microdont outside the bone and above the occlusal plane of the retained maxillary right second molar. The supernumerary tooth was completely embedded in oral soft tissue. Hyperplastic oral soft tissue in the molar region and microdont were excised. Specimen of the mucosa surrounding the teeth was interspersed with diffuse and plexiform neurofibroma. The retained upper right first molar emerged spontaneously within a few months after surgery. The upper right second molar did not change position. CONCLUSION: Odontogenesis can take place within tumorous oral mucosa in NF1. Surgical removal of the tumorous mucous membrane facilitates tooth eruption in some cases.

Sphenoid Bone Pneumatisation on Lateral Cephalograms of Patients With Neurofibromatosis Type 1.

BACKGROUND/AIM: Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary disease that causes tumors and many developmental disorders, e.g., cranial dysplasia. The purpose of this retrospective study was to analyse the pneumatisation of the sphenoid bone in NF1. PATIENTS AND METHODS: The anonymised lateral cephalograms of 166 NF1 patients and 166 age- and sex-matched controls were examined for anterior-posterior sphenoid pneumatisation. The patient group analysis considered whether the patients had been affected by a facial plexiform neurofibroma (FPNF). RESULTS: Sphenoid pneumatisation was significantly lower in NF1 patients than in controls [odds ratio (OR)=0.184; 95%CI=0.11-0.32; p<0.001]. A FPNF statistically significantly reduced sinus formation in patients (OR=0.38; p=0.002). CONCLUSION: The condition 'NF1' has an effect on sphenoid pneumatisation. The findings are relevant for planning surgical procedures in this region and confirm current concepts to evaluate NF1 as a histogenesis control gene. The examination technique and basis of calculation presented here are easy-to-use and low-irradiation exposure instruments for screening for differences in sphenoid bone pneumatisation in defined populations.

Supernumerary teeth of permanent dentition in patients with neurofibromatosis type 1.

PURPOSE: The purpose of the study was the investigation of supernumerary teeth (ST) in the permanent dentition of patients with neurofibromatosis type 1 (NF1). MATERIAL AND METHODS: The panoramic radiographs of 200 NF1 patients were analysed for ST. The potential impact of certain neurogenic facial tumours on the measured variable was investigated separately. The results were compared to dental findings in panoramic radiographs of 200 age- and sex-matched controls. RESULTS: The total number of ST in all individuals was 23 in 12 patients (3% of total population). However, all ST had developed in the group of NF1 patients (6%), (p = 0.0004). ST were particularly common distal to the molar region. Although ST occur in the region of facial plexiform neurofibroma, the numerical aberrations of the dentition are independent of specific type of facial nerve sheath tumour. CONCLUSION: The unusual accumulation of ST in the terminal sections of molar development could be an indicator of preferred points of developmental disorder, in which the genetic predisposition of the patient is involved. Reviewing the results of other NF1 patient collectives is desirable.

The effect of bisphosphonate medication on orthodontics and orthognathic surgery in patients with osteogenesis imperfecta.

Introduction: Osteogenesis imperfecta (OI) is a genetic disease that primarily affects bone formation and metabolism. Craniofacial malformations belong to the broad spectrum of the OI phenotype. The introduction of bisphosphonate medications was intended to counteract the significant brittleness of the bones of OI patients. In connection with the application of bisphosphonates, drug-associated osteonecrosis of the jaw has become known as an undesirable effect of the therapeutically intended reduction of osteoclast activity. Originally, the pharmacological inhibition of bone loss was mainly used in oncological therapy. For some time now, osteoporosis has also been treated with substances that inhibit bone resorption. In OI, malposition of the jaws is relatively common, in particular retrognathia of the maxilla and progeny of the mandible. The literature discloses complications of orthognathic surgery in OI patients. Previous literature reviews suggest that bisphosphonate medication has no significant impact on the performance of and healing after oral surgery in OI patients. Material and methods: An essential prerequisite of a therapy adapted to the patient's condition is the knowledge of the patient's medical history. This case report describes the orthodontic-surgical treatment of an OI patient and the treatment experience derived in dealing with the condition. The unusual circumstance of this case is that the patient had concealed both his underlying disease and his medication during the current treatment period. In addition, the relevant literature is evaluated for combining the keywords OI, orthodontic therapy, bisphosphonates, and orthognathic surgery. Results: Based on the literature and our own experience, it is concluded that orthodontic treatment with bisphosphonate medication can also be carried out in OI patients. However, considerably greater forces and longer time intervals should be scheduled for each treatment. Orthognathic surgery with bisphosphonate medication turned out to be uncomplicated in our own case, considering the underlying disease in the planning of surgical procedures. However, there have been very few reports of OI patients in whom orthodontic-surgical treatment of jaw malformation has been performed with bisphosphonate medication. Conclusion: Taking into account the reported experience of severe complications of orthognathic surgery, the multiple documented adjustments to the treatment strategy of OI patients should be taken seriously. The basic condition of therapy adapted to the disease is that the patient informs the practitioner in an appropriate manner about his or her state of health.

Unilateral Creeping Destruction of Deformed Mandibular Ramus and Angle Associated with Extensive Facial Plexiform Neurofibroma in Neurofibromatosis Type 1: A Case Report with Analysis of the Literature for Diagnosing Osteolytic Events of the Mandible in Tumor-suppressor Gene Syndrome.

Neurofibromatosis type (NF1) is an autosomal dominant inherited tumor-suppressor gene syndrome of significant phenotypic variability with probable complete penetrance of the disease. Skeletal malformations of the skull belong to the phenotype of NF1. In the skull, defects of the calvaria and the sphenoid bone are diagnostically groundbreaking findings in NF1. Malformations of the facial skull are usually diagnosed in patients with NF1 in a topographical context with a plexiform neurofibroma (PNF). This report describes the rare occurrence of slowly advancing, unilateral destruction of proportions of the mandible in NF1, with the affected bone segment completely surrounded by a PNF. A malignant process was ruled out as a cause of partial organ loss. Various hypotheses on the pathogenesis of the rare finding are presented.

Sella turcica measurements on lateral cephalograms of patients with neurofibromatosis type 1.

The aim of this study was to measure line segments and areas of sella turcica on lateral cephalograms with respect to the clinical diagnosis of facial phenotype of patients with neurofibromatosis type 1 (NF1). Special attention was given to correlate the measured values with certain tumour types that are typical for this disease. Material and methods: Lateral cephalograms of 194 individuals were investigated. Patients with NF1 were further divided according to the detection and topography of facial plexiform neurofibromas (PNF) taking into account the distribution pattern of the trigeminal nerve. All patients with PNF showed unilateral tumour localisation. Patients without any facial PNF constituted a separate group. Healthy volunteers with ideal occlusion and no history of any intervention in the maxillofacial region served as a control group. The following items were determined on the radiographs: sella entrance, sella width, sella depths, sella diagonal, and sella area. Results: Patients with PNF of the first and second trigeminal nerve branch or affected in all branches showed highly statistically significant enlarged sella tucica measurement values. On the other hand, patients with PNF restricted to one branch only or simultaneously in the second and third branches showed measurement values that were not different to those obtained in NF1 patients devoid of facial PNF. The latter group also showed no difference of sella turcica parameters obtained in the control group. Conclusion: This study provides evidence for the association of a certain NF1 phenotype with distinct skeletal alterations of the skull base, shown here using the example of the representation of the sella turcica in the lateral radiograph. These findings are also relevant in the discussion of NF1 as a disease of bones and in the assessment of brain development in NF1. Both items are discussed in relationship to a facial plexiform neurofibroma. Furthermore, the knowledge of this association of findings provides the clinician with relevant information in the planning of skull base procedures in these patients.

A lateral cephalometry study of patients with neurofibromatosis type 1.

PURPOSE: Neurofibromatosis type 1 (NF1) is an autosomal dominant transmitted tumour suppressor syndrome and also a bone disease. Osseous dysplasia affecting the craniofacial region is characteristic of NF1. The aim of this study was to analyse the lateral cephalograms of NF1 patients in comparison to individuals who were not affected by this condition in order to describe the skeletal phenotype of NF1 in more detail. MATERIALS AND METHODS: The study comprises the lateral cephalograms of 172 patients with established NF1 diagnoses (female = 85, male = 87). NF1 patients were distinguished by radiological and/or histological findings of the facial region suggestive of plexiform neurofibroma (PNF) or disseminated cutaneous NF (DNF). The analysed radiographs of a collection of 29 healthy volunteers with ideal occlusion served as controls. The focus of this analysis was cephalometrically defined angles. RESULTS: Cephalometric analyses of patients with DNF did not differ from those of controls for the vast majority of parameters. However, the measurement results of patients with PNF differed significantly from those of healthy volunteers and patients with DNF. The number of trigeminal nerve branches affected in PNF patients had an effect on the measurement results. CONCLUSION: Lateral cephalograms revealed no significant alteration of the facial skeleton in NF1 patients as compared to controls. Indeed, the stigma of a so-called 'NF1 facies' cannot be derived from the cephalometric findings presented. Notably, a wide range of deviating readings were recorded for individuals with facial PNF. Clinicians who treat patients with NF1 should be aware of deviations from cephalometric standards on lateral cephalograms in NF1 patients, especially when craniofacial surgical procedures are planned. Some of these findings, particularly asymmetries of the facial skeleton, could be indicators of an associated PNF.

Cherubism: A Case Report with Surgical Intervention.

Cherubism is a rare benign, autosomal-dominant hereditary fibro-osseous condition predominantly affecting the jaws. Symmetrical cyst-like expansions of the jaws cause the characteristic facial swellings. The disease is often associated with severe malposition of teeth. The gene for cherubism is src homology 3 binding protein 2 (SH3BP2) located on chromosome 4p16.3. The repeated experience of this self-limiting disorder in affected individuals published in the medical literature has resulted in a wait-and-see strategy regarding therapeutic options. Indeed, cessation and regression of even large bone expansions can be expected in early adulthood. Nevertheless, severe facial disfiguring and functional impairment can make surgical intervention necessary. This report details the surgical procedures carried out in a patient with progressive and disfiguring jaw expansions at the end of adolescence, the mutation of SH3BP2 gene, and the limited effect of surgically assisted orthodontic tooth movement in a patient with disease-associated impaired tooth development and tooth eruption.

Recurrent Maxillary Odontogenic Myxoma Following Partial Maxillary Resection and Consecutive Osseous Reconstruction Including Tooth Transplantation.

Odontogenic myxoma (OM) is a rare tumour arising in the jaws. The tumour is purported to be odontogenic in origin due to the frequent localisation of the tumour inside the jaws in close relation to teeth. The aim of this report was to detail the course of a patient who developed OM of the maxilla, underwent adequate ablative surgery and reconstruction, including tooth transplantation to the original tumour site, and subsequently developed a local recurrence in close proximity to the teeth transplanted to the reconstructed maxilla 6 years after the first diagnosis. Once again, a partial maxillary resection was performed, with no reconstruction. The patient has been free from tumour recurrence for over 20 years. We discuss the current hypothesis on OM pathogenesis and the possible impact of actively dividing cells on tumour re-growth.

Lateral periodontal cyst.

The lateral periodontal cyst (LPC) is a harmless developmental aberration derived from odontogenic epithelia lying between the roots of vital teeth. The exact histogenesis of LPC is a matter of debate but therapy is usually only required to maintain stable periodontal conditions and in case of evidence for growth of the cyst. We report on a case of LPC where successful surgical therapy had initialized osseous restoration. We further discuss the value of histological findings to substantiate a clinical and radiological diagnosis.

Inflammatory paradental cyst of the first molar (buccal bifurcation cyst) in a 6-year-old boy: case report with respect to immunohistochemical findings.

The inflammatory paradental cyst (IPC) is a relatively rarely reported lesion arising from the lateral periodontium of vital teeth. However, IPC appear to be under-represented in registers of odontogenic cysts due to the misinterpretation of IPC as infected dentigerous cysts, in particular IPC originating from third molars. IPCs exhibit some temporospatial associations with tooth eruptions and occur almost exclusively in the mandible. The IPC of the first molar is predominantly diagnosed in children younger than 10 years. Bony bulging in the area of cyst formation may alert parents to seek medical advice. This case report details the characteristic clinical and radiological features of a first molar IPC arising in a child. The features of the presented cyst correspond well to the attributes qualifying for a so-called buccal bifurcation cyst. A conservative treatment regimen proved to be successful. Certain immunohistochemical markers are reported to further characterize this entirely benign lesion.

Pseudoepitheliomatous hyperplasia associated with bisphosphonate-related osteonecrosis of the jaw.

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a well-characterized oral complication of systemic therapy with bisphosphonates. Pseudoepitheliomatous hyperplasia was observed in some of the lesions. Because podoplanin expression has been linked to malignant lesions of the oral mucosa, we aimed to investigate podoplanin expression in the pseudoepitheliomatous hyperplasia. We analyzed archival paraffin- and plastic-embedded specimens from BRONJ using both conventional and immunohistochemical (AE1/AE3, D2-40) staining methods. Eleven out of seventeen BRONJ cases showed pseudoepitheliomatous hyperplasia. All these cases were positive for AE1/AE3 and pseudoepitheliomatous hyperplasia displayed a strong basal and parabasal reaction against podoplanin. The podoplanin expression in pseudoepitheliomatous hyperplasia in BRONJ specimens should not be considered a sign of malignancy. We discuss the current and possible future roles of surgical pathologists in diagnosing morphological changes associated with the development and therapy of BRONJ lesions.

Enhanced podoplanin expression in chronic maxillary sinusitis.

Podoplanin expression has been reported in oral squamous epithelium, myoepithelia of the salivary glands, and odontogenic lesions, and has been linked with inflammatory and neoplastic conditions. We hypothesized that inflamed respiratory mucosa of the maxillary sinus also express podoplanin, especially in cases with odontogenic sinusitis. We retrospectively investigated podoplanin expression in biopsies from maxillary sinus with inflammatory changes. Cases with chronic rhinosinusitis with polyp formation (n=5), chronic rhinosinusitis without polyps (n=5), chronic rhinosinusitis with eosinophilia (n=5), and odontogenic chronic rhinosinusitis (n=5) were investigated immunohistochemically using an established antibody for podoplanin (D2-40). Respiratory epithelium in chronic maxillary sinusitis with polyp formation did not exhibit enhanced podoplanin expression. However, D2-40 positivity was detected in the basal cells in all cases with chronic sinusitis associated with inflammatory infiltrations as well as in the parabasal epithelial layer in chronic sinusitis without polyp formation. We observed podoplanin expression in non-neoplastic maxillary sinus epithelium exhibiting inflammatory changes. We suggest that podoplanin is involved in the pathogenesis of chronic rhinosinusitis, particularly in the intraepithelial migration of inflammatory infiltrates.

Analysis of orbital plain radiographs for orbital deformities in neurofibromatosis type 1 patients, with special reference to alterations of the orbital rim as indicators of adjacent plexiform neurofibroma.

UNLABELLED: Neurofibromatosis type 1 (NF1) is an autosomal dominant inherited disease. Some stigmata of NF1 occur in the orbital region. The aim of this study was to reveal whether alterations of the orbital rim visible on plain radiographs may indicate the presence of a plexiform neurofibroma (PNF), a tumour almost exclusively diagnosed in NF1. MATERIAL AND METHODS: The plain orbital radiographs of 73 patients with NF1 (female: N=37, male: N=36) were investigated for alterations of the orbit. The group was further distinguished according to the presence of orbital PNF (N=53) and/or sphenoid wing dysplasia (N=30). Radiographs from patients with NF1 and with exclusion of PNF in the orbitofacial region were used for comparison (N=20). A special cephalometric analysis (Dental Vision™) was adapted to the demands of this study. RESULTS: Patients with NF1 not affected by an orbitofacial PNF exhibited symmetrical orbits. Unilateral increase in orbital height was associated with ipsilateral PNF. The width of orbits affected by a PNF was often slightly increased compared to the non-affected side. The determination of cephalometrically-defined angles disclosed an erection of the PNF-affected orbit compared to the medio-sagittal plane. CONCLUSION: Plain radiographs are often the first diagnostic measure used to determine skeletal alterations. This study shows that certain parameters of the orbital rim are useful indicators of a PNF in patients who are unilaterally affected by this lesion in the orbital or orbitotemporal region.

An unilateral basal bone defect of the mandible occupied by fatty tissue: Stafne's cavity.

The differential diagnosis of osseous jaw lesions includes numerous entities. A specific mandibular bone defect known as Stafne's cavity or cyst presents wirh a characteristic cyst-like lesion on radiographs of the jaw. Although the differential diagnosis from other jaw lesions is mandatory, this lesion does not usually require surgical therapy. Current theories concerning the pathogenesis of Stafne's cavity prefer bone depression as a consequence of constant pressure arising from an adjacent salivary gland. We present a case of a large Stafne's cavity eroding the basal mandibular cortex that was found accidentally on an orthopantogram taken for diagnosis of dental diseases. The patient noted a slight pain on pressure during physical investigation. The lesion was completely occupied by fatty tissue, as shown during surgical exploration and as revealed by histological investigation of the specimen. The theory of parenchymal pressure as the cause of mandibular bone depression appears to be inapplicable in the present case. The pathogenesis of Stafne's cavity is still obscure. Differential diagnosis of mandibular lesions is essential in adequate treatment planning.