Persistent bone resorption lacunae on necrotic bone distinguish bisphosphonate-related osteonecrosis of jaw from denosumab-related osteonecrosis.

BACKGROUND: Bisphosphonate and denosumab are widely used for the treatment of osteoporosis and bone metastasis of cancer to prevent excessive bone resorption. Osteonecrosis of the jaw is a serious adverse effect of bisphosphonate or denosumab referred to as bisphosphonate-related osteonecrosis of the jaw (BRONJ) or denosumab-related osteonecrosis of the jaw (DRONJ), respectively. Since bisphosphonate and denosumab inhibit bone resorption by different mechanism, we evaluated whether these drug types result in different histopathological characteristics related to bone resorption. MATERIALS AND METHODS: We histopathologically investigated 10 cases of BRONJ, DRONJ, and suppurative osteomyelitis. Paraffin sections prepared from decalcified dissected jaw bones were used for histopathological observation, second harmonic generation imaging, and bone histomorphometry. The samples were also observed by a scanning electron microscope. RESULTS: Numerous bone resorption lacunae were observed on the necrotic bone surface in almost all cases of BRONJ; however, such resorption lacunae were limited in DRONJ and suppurative osteomyelitis. Prominent bone resorption lacunae were also confirmed by second harmonic generation imaging and scanning electron microscopy in BRONJ, but not in DRONJ or suppurative osteomyelitis. As determined by bone histomorphometry, the number of bone resorption lacunae and the length of the erosion surface of resorption lacunae were significantly higher in BRONJ group than in the DRONJ and suppurative osteomyelitis groups. These parameters were correlated between the necrotic bones and the vital bones in BRONJ. CONCLUSIONS: Persistent bone resorption lacunae on the necrotic bone surface are unique to BRONJ, providing a basis for distinguishing BRONJ from DRONJ and OM in histopathological diagnosis.

Three-Dimensional Analysis of Soft and Hard Tissue Changes following Orthognathic Surgery.

Change in soft tissue in relation to that in hard tissue following orthognathic surgery was evaluated. Twenty-five patients were enrolled in the study. The diagnosis in all was jaw deformity (maxillary retrusion and mandibular protrusion) and all underwent a Le Fort I osteotomy and bilateral sagittal splitting ramus osteotomy. Three-dimensional (3D) computer-aided design (CAD) models (polygon models) of the hard and soft tissue of the maxilla and mandible were constructed and superimposed. Reference points were established on the pre- and postoperative hard and soft tissues. Specific elements of each reference point were divided into X, Y, and Z components, respectively, and the distances in each direction and 3D distance (normal distance) measured. The Wilcoxon signed-rank test was used to determine differences in the mean values for the distance moved of each element as the error between pre- and postoperatively. The results revealed statistically significant differences in the Y-direction in the maxilla and the X- and Z-directions in the mandible. A significant difference was also observed in the 3D distances of the maxilla and mandible. Little evidence was found of linearity between the amount of hard and soft tissue movement in the X- and Z-directions in the maxilla. This means that 3D movement in the maxilla was masked more by changes in the morphology of the soft tissue than in the mandible, making it less evident. The results of this study suggest that the 3D analysis method used enables changes in hard and soft tissues to be understood qualitatively, and that it can be used in diagnosis and treatment in orthognathic surgery. It may also be useful in simulation of morphological change in soft tissue.

Three-Dimensional Evaluation of Pharyngeal Morphology in Bimaxillary Surgery with and without Horseshoe Osteotomy in Skeletal Class III Cases.

Repositioning of the jaw in orthognathic treatment generates changes in the soft tissues of the maxillofacial region, with consequent changes in the airway. The purpose of this study was to determine how type of orthognathic surgical procedure affected the 3-dimensional morphology of the upper airway. Forty patients were divided into the following 2 groups according to the type of surgical procedure used: a horseshoe osteotomy (HS) group (20 patients, comprising 11 men and 9 women; average age 24.3±4.5 years) who underwent bimaxillary surgery; and a LeFort I osteotomy (LF) group (20 patients, comprising 8 men and 12 women; average age 22.5±4.6 years) who also underwent bimaxillary surgery. Cephalometric measurements were taken and 3-dimensional pharyngeal morphology evaluated in each group. The amounts of maxilla rotation, posterior maxilla impaction, and mandibular setback all revealed a significantly larger value in the HS group. Evaluation of pharyngeal volume revealed a significant decrease in the upper pharyngeal segment in the LF group. A significant decrease in the lower pharyngeal segment was observed in both groups. Differences were noted in postoperative pharyngeal morphology between the two groups. The results of this study suggest that HS has less effect on the upper pharyngeal segment, regardless of the amount of posterior maxilla impaction.

Antimicrobial susceptibility surveillance of bacterial isolates recovered in Japan from odontogenic infections in 2013.

We report on the findings of the first antimicrobial susceptibility surveillance study in Japan of isolates recovered from odontogenic infections. Of the 38 facilities where patients representing the 4 groups of odontogenic infections were seen, 102 samples were collected from cases of periodontitis (group 1), 6 samples from pericoronitis (group 2), 84 samples from jaw inflammation (group 3) and 54 samples from phlegmon of the jaw bone area (group 4) for a total of 246 samples. The positivity rates of bacterial growth on culture were 85.3%, 100%, 84% and 88.9%, respectively, for groups 1, 2, 3 and 4. Streptococcus spp. isolation rates according to odontogenic infection group were 22% (group 1), 17.7% (group 3) and 20.7% (group 4). Anaerobic isolation rates were 66.9% (group 1), 71.8% (group 3) and 68.2% (group 4). Drug susceptibility tests were performed on 726 strains excluding 121 strains that were undergrown. The breakdown of the strains subjected to testing was 186 Streptococcus spp., 179 anaerobic gram-positive cocci, 246 Prevotella spp., 27 Porphyromonas spp., and 88 Fusobacterium spp. The isolates were tested against 30 antimicrobial agents. Sensitivities to penicillins and cephems were good except for Prevotella spp. The low sensitivities of Prevotella spp is due to ß-lactamase production. Prevotella strains resistant to macrolides, quinolones, and clindamycin were found. No strains resistant to carbapenems or penems were found among all strains tested. No anaerobic bacterial strain was resistant to metronidazole. Antimicrobial susceptibility testing performed on the S. anginosus group and anaerobic bacteria, which are the major pathogens associated with odontogenic infections, showed low MIC90 values to the penicillins which are the first-line antimicrobial agents for odontogenic infections; however, for Prevotella spp., penicillins combined with ß-lactamase inhibitor showed low MIC90 values.

Luminal, Intramural Unicystic Ameloblastoma with Marked Fluid-Fluid Level: Validity of CT and MRI Findings.

We report herein a case of a luminal and intramural unicystic ameloblastoma (UA) with a marked fluid-fluid level. The validity of imaging findings in diagnosing UA in the present case is discussed in reference to the literature. The patient was a 50-year-old woman who presented with swelling of the gingiva in the region of the left mandibular third molar and numbness in the lower lip. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a large mass lesion with a unilocular appearance and a biphasic aspect, suggesting liquid content. Contrast-enhanced MRI (CE-MRI) and dynamic contrast-enhanced MRI (DCE-MRI) demonstrated that the biphasic aspect indicated a fluid-fluid level with no blood pooling/flow; it also revealed a thick rim-enhanced margin with mural protrusion. Postoperatively, the lesion was histopathologically diagnosed as a luminal and intramural UA. In conclusion, extensive imaging including both standard CT and MRI together with CE-MRI and DCE-MRI allowed mural protrusions or nodules on a thick cystic wall and liquid content to be correctly identified. This suggests that such imaging can play an important role in diagnosing a UA, even though the results were at first misleading due to the marked fluid-fluid level.

A Case of Fibrolipoma of the Hard Palate.

An extremely rare case of fibrolipoma in the hard palate is presented and discussed with reference to the literature. An 85-year-old woman visited the Tokyo Dental College Chiba hospital in September 2016 with the chief complaint of a mass in the hard palate. The patient had first become aware of this mass several years earlier. An examination at another hospital in June 2009 resulted in a clinical diagnosis of lipoma. Regular examinations followed every 6 months until September 2014, at which time she stopped attending these appointments because there was no change. In August 2016, however, the patient realized that the tumor was increasing in size. Although there was no pain, awareness of a foreign body in the oral cavity when eating or talking was increasing, so she decided to visit our clinic for detailed examination and treatment. At this point, the mass extended from the center to the left side of the hard palate. It measured 15 mm along the major axis, and had a clear border; nearly spherical, its surface was smooth and glossy, and was of a slightly yellowish color. The mass was painless, elastic, and soft. Computed tomography and magnetic resonance imaging revealed a tumorous lesion. Based on a clinical diagnosis of lipoma, it was subsequently excised under general anesthesia in January 2017. The tumor lay under the palatal mucosa, extending from the center to the left side of the hard palate. It was surrounded by a single-layered membranous structure, and had not adhered to the surrounding tissues. Healthy palatal mucosa and periosteum were also removed en bloc with the tumor within a safety margin of approximately 5 mm. No pressure absorption of palatine bone was seen. Histopathologically, proliferation of mature adipose tissue was observed. This was surrounded by a thin, single-layer membrane within the subepithelial connective tissue, which was covered by stratified squamous epithelium. Proliferation of fibrotic connective tissue was seen between the adipocytes. The final diagnosis was fibrolipoma. To date, at 18 months postoperatively, no recurrence has been observed and progress has been satisfactory.

Antiresorptive Agent-Related Osteonecrosis of the Jaw (ARONJ): A Twist of Fate in the Bone.

Bisphosphonates (BPs) have been used as antiresorptive agents to treat patients with osteoporosis or metastatic bone cancer, each of which is characterized by bone loss due to the increased bone resorption. However, BPs could cause osteonecrosis of the jaw (ONJ), known as bisphosphonate-related osteonecrosis of the jaw (BRONJ). ONJ is associated with severe pain and deteriorated quality of life. ONJ is also caused by administration of denosumab, a monoclonal antibody against receptor activator of NFκB ligand (RANKL), that functions as a powerful antiresorptive agent. Accordingly, antiresorptive agent-related ONJ (ARONJ) has been advocated, the incidence of which is continuing to increase in Japan as a super-aging society. Importantly, the jawbone is more susceptible to infection compared with bones in other parts of the body, due to the unique anatomical and physiological characteristics; for example, the jawbone with a high remodeling rate is stimulated by teeth during mastication. The risk factors of ARONJ include dental infection, poor occlusal or oral hygiene status, and bone-invasive dental treatment, such as tooth extraction, dental implants, and dentures. Proper collaboration between doctors and dentists is of utmost importance to understand the current status of ARONJ and prevent developing ARONJ. It is also important to ensure that the patients treated with BPs or denosumab can receive appropriate dental treatment. More recently, angiogenesis inhibitors were reported to cause ONJ; thus, medication-related ONJ (MRONJ) has been advocated. This article overviews the concept of MRONJ by focusing on antiresorptive agents and the status of BRONJ in Japan.

Surgical Management of Median Cleft Lip Extending as Far as Alveolus Using Bone Grafting.

Median clefts, which run through the midline of the upper lip, and alveolus are considered a type of craniofacial cleft. A Tessier number 0 median cleft lip is the rarest, and there are few reports concerning its surgical management. Here, we describe the case of a 6-year-old boy who presented at our hospital with a median cleft and alveolus of the upper lip with a shortened bifid frenulum. Inverted-V and Z-plasty incisions were performed for the median cleft and iliac bone grafting for the midline alveolus. At 1 year 5 months later, the postoperative course was uneventful, and proper approximation of the orbicularis oris muscle and vermilion were achieved, with a symmetrical Cupid's bow and labial tubercle and philtrum.

Ten-year Clinical Trends among 575 Consecutive Oral Cancer Patients at Tokyo Dental College Oral Cancer Center.

The facilities comprising Tokyo Dental College (TDC) -the college itself and its medical institutions at Suidobashi, Ichikawa, and Chiba - have been officially recognized as a center for treating oral cancer. The TDC Oral Cancer Center (OCC) was established on April 1, 2006. It provides comprehensive medical care, including that aimed at recovery of postoperative function, such as restoration of stomatognathic function, dysphagia therapy, and placement of maxillary prostheses. The purpose of this study was to investigate patient trends at TDC-OCC over the 10 years following its establishment in order to determine how the safe and high-quality cancer care already provided might be even further improved. Oral cancer patients attending TDC-OCC between April 2007 and March 2017 were investigated. Clinical information was obtained from medical records and analyzed, including that on patient numbers, age, sex, primary site of tumor, clinical stage, and surgery provided. There were 758 new cases, and the number of new cases showed an annual increase. Among the total number of new patients, 575 (75.9%) represented primary cases. The number of operations also showed an increase, which correlated with the increase in the number of patients. The incidence in oral cancer has increased in several countries, including Japan. Oral cancer can be observed macroscopically and touched. In contrast to with cancers at many other sites, and despite various diagnostic devices for early detection having been developed, however, cases are often advanced when first encountered. Many advanced cases were treated at TDC-OCC, and the number of reconstructive operations following progressive cancer also increased over time.

National Survey on Bisphosphonate-Related Osteonecrosis of the Jaws in Japan.

PURPOSE: From 2011 to 2013, a nationwide retrospective cohort study was conducted by the Japanese Society of Oral and Maxillofacial Surgeons and the Japanese Society of Dentistry for Medically Compromised Patients to assess the development of bisphosphonate (BP)-related osteonecrosis of the jaws (BRONJ) and to elucidate the outcomes and factors associated with remission. MATERIALS AND METHODS: A written questionnaire, including clinical characteristics, management, and outcomes of patients with BRONJ, was sent to 501 institutions. RESULTS: This large-scale study included 4,797 cases with a female preponderance. BRONJ occurred twice as often in the mandible as in the maxilla. Most patients had BRONJ stage 2 (61.4%), followed by stage 1 (20.7%) and stage 3 (16.8%); stage 0 was excluded. The most common primary disease was malignant neoplasm (46.5%), followed by osteoporosis (including prevention; 45.3%). The proportion of patients on oral BPs increased, with the incidence approaching that of patients receiving parenteral BP. Surgical therapy rates of patients with BRONJ stages 1, 2, and 3 were 14.0, 37.6, and 53.5%, respectively. Outcome assessment for 936 patients with BRONJ stage 2 who underwent surgical therapy indicated remission in 46.3% of cases, improvement in 30.6%, disease progression in 5.4%, and no change in 6.1%. Good prognosis (remission or improvement) was seen in 76.9% of cases and poor prognosis (disease progression or no change) was seen in 11.5%. Analysis showed that risk factors for onset of BRONJ (P = .031), surgical procedure (P < .024), condition of the wound (P = .017), and discontinuation of BP (P < .001) were factors affecting prognosis. CONCLUSION: The number of patients with BRONJ has increased in Japan. Attention to oral BP and proper treatment is required to minimize the number of cases. Surgical therapy seems to be effective for BRONJ stage 2.

Morphologic Evaluation for Safe Le Fort I Osteotomy in Cleft Lip and Palate.

OBJECTIVE: The present study aimed to determine the structure and morphology of the maxilla in patients with cleft lip and palate to ensure safe Le Fort I osteotomy. PATIENTS: A total of 34 sides of 17 patients with unilateral cleft lip and palate (nonsyndromic cases) were included in this study. The control group included 10 sides of 5 patients who exhibited skeletal mandibular protrusion without malformation. METHODS: Finite element analysis was performed to examine the distribution of occlusal force over the maxilla, and continuous 3-dimensional measurement was performed at the sites of stress concentration. RESULTS: In patients with cleft lip and palate, bones at the lateral border of the piriform aperture and the anterior wall of the maxillary sinus were significantly thicker than those in controls ( P < .05). Furthermore, the attachment of the pterygomaxillary junction was wider and thicker ( P < .05), and the anterior distance to the descending palatine artery was shorter ( P < .01) in patients with cleft lip and palate than in controls. Our results further indicated that alveolar bone grafting may significantly influence bone thickness and the attachment state of the pterygomaxillary junction. CONCLUSIONS: Our results suggest that the complications of LFI can be reduced in patients with cleft lip and palate by ensuring proper understanding of each patient's maxillary anatomy and bone thickness, as well as the location of the descending palatine artery and the attachment state of the pterygomaxillary junction.

Comparative Study of Mandible Ramus Morphology Using 3-dimensional CT in Sagittal Split Ramus Osteotomy.

The purpose of the present study was to investigate the relevance of the external morphology of the mandibular ramus, internal bone tissue structure, and maxillofacial morphology at the site for sagittal split ramus osteotomy among different facial skeletal patterns. A total of 80 patients with jaw deformities who underwent sagittal split ramus osteotomy were included in the study. The patients were divided into two groups based on facial skeletal type (skeletal Class II or skeletal Class III). A further 7 patients with no skeletal abnormalities were established as the control group (skeletal Class I). Computed tomography images obtained from these patients were 3-dimensionally reconstructed and the morphology of the mandibular ramus determined. Thickness at the mandibular foramen in Class II was greater than that in Class III, and showed the lowest value at the midpoint of the mandibular foramen and mandibular notch in Class I. Mandibular morphology showed change according to facial skeletal type. Correlations were also observed between the cephalometric analysis values and mandibular morphology.

Three-dimensional Analysis and Evaluation in Orthognathic Surgical Cases with Facial Asymmetry.

Two-dimensional cephalometric analysis is commonly used in planning and evaluating the outcome of orthognathic surgery. It is difficult to arrive at an accurate evaluation with this method, however, as the jaw bones overlap in profile. Therefore, the purpose of this study was to use 3-dimensional (3-D) orthognathic treatment planning software for measurement of distances and angles to evaluate change in dentofacial morphology and stability after orthognathic surgery in patients with jaw deformity and facial asymmetry. Computed tomography with SimPlant O&O® (Materialize Dental, Belgium) was used to obtain data at before surgery (T1) and at 1 month (T2) and 1-2 years postoperatively (T3). Reference points, reference planes, and evaluation items were set to measure angles and distances. The average values at T1, T2, and T3 and the standard deviations were obtained. The analyses of change in distance and angle between T1 and T2 in both the maxilla and mandible revealed that the amount of postoperative deviation and change was greatest in the mandible (p<0.05). These findings showed a correlation between postoperative change in position of the chin and symmetry. Only a minimal amount of change was observed between T2 and T3 in both the maxilla and mandible. The results also revealed a correlation between positional change in both the proximal and distal bone segments and stability. It was found to be possible to determine change in horizontal, vertical, and anterior/posterior angle in both the maxilla and mandible by such 3-D analysis. The results suggest that the chin is the most appropriate facial element for evaluation of symmetry after orthognathic surgery.

Three-dimensional Finite Element Analysis of Bone Fixation in Bilateral Sagittal Split Ramus Osteotomy Using Individual Models.

The purpose of this study was to investigate factors involved in stress on locking mini-plate/screws used in orthognathic surgery based on patient-specific 3-dimensional finite element analysis. Data were obtained from 10 patients undergoing mandibular advancement by bilateral sagittal split ramus osteotomy. All underwent osteosynthesis with 2.0-mm titanium locking mini-plate/screws. A 3-dimensional finite element model of the mandible was created for each patient and each model subjected to the same loading conditions, which produced different stress values on locking mini-plate/screws. When the contact area of the proximal and distal bone segments was narrower and bone mineral density (BMD) lower, the von Mises stress values on the plate/screws were higher (contact area, p<0.01; BMD, p<0.05). The present results suggest that bone contact area and BMD should be considered as plate stress factors.

Mandibular Reconstruction with Free Vascularized Fibular Graft.

An iliac block graft is the most commonly used biomaterial for reconstruction following resection of the mandible. Its use has some disadvantages, however, including limitations on the amount of bone that may be harvested, and the subsequent increase in burden on the iliac bone. Therefore, recently, free vascularized fibular grafts have been used as an alternative in some cases. Here, we report the advantages of, and issues related to reconstruction using free vascularized fibular grafts observed at Tokyo Dental College Chiba Hospital. Eight patients undergoing mandibular reconstruction using free vascularized fibular grafts between January 2003 and January 2017 were investigated. Of these, 6 were men, and 2 were women. Age ranged from 38 to 74 years (average, 54 years). Primary diseases comprised malignant tumor in 3 patients, benign tumor in 3, and radiation osteomyelitis of the mandible in 2. The defects were classified as follows according to the CAT system (Condylar Head, Mandibular Angle, Mental Tubercle): 3 cases of Body, 2 of AT, and 1 case each of TT, ATTA, and CATT. The resection range of the mandible was 5-16 cm (average, 10 cm). The single barrel technique was used in 7 cases, and the double barrel technique in 1. In terms of the flap survival ratio, complete engraftment was achieved in 6 out of the 8 cases. Two cases of radiation osteomyelitis of the mandible, with necrosis caused by vascular breakdown after wound infection, were observed, however. While the advantages of mandibular reconstruction by this method include comparatively safe conditions and functional recovery, there were also some problems. It was inappropriate for cases of radiation osteomyelitis of the mandible; those where anti-inflammatory therapy was ineffective; and those where greater resection of the soft tissue was required. Further study is needed to clarify the criteria for selecting this procedure.

Verruciform Xanthoma with Equivocal Exfoliative Cytological Diagnosis.

Verruciform xanthoma (VX), a papillary or wart-like lesion of the mucosa, is histopathologically characterized by papillary projection of the epithelium and an aggregation of foam cells in the lamina propria. Here, we describe a case of VX in the posterior mandibular gingiva, initially suspected to be a benign lesion based on clinical findings and cytology prior to an excisional biopsy. The patient was a 62-year-old man who had visited a local dentist approximately 1 year earlier, presenting with a white lesion in the left posterior mandibular gingiva that resisted removal by scraping. The lesion was left untreated as there were no subjective symptoms. Thereafter, the surface of the lesion roughened and the patient was referred to our department for a comprehensive examination. A circumscribed, granular mass, 15-mm in diameter, with a red and white surface was observed in the left posterior mandibular buccal gingiva. Exfoliative cytology was performed. The diagnosis was a class III lesion. Excisional biopsy was performed under local anesthesia. Histopathological examination led to a diagnosis of VX. At 1 year postoperatively, the patient is making satisfactory progress without recurrence. Verruciform xanthoma is difficult to diagnose preoperatively, and is commonly resected under a clinical diagnosis of papilloma or benign tumor. A benign lesion was also initially suspected in the present case and cytological analysis performed to confirm absence of malignancy. The lesion could not be diagnosed as VX preoperatively. Verruciform xanthoma can be over-diagnosed based solely on cytological examination because it often involves cellular atypia reflecting its characteristic extension of rete pegs and keratinization of surface cells, indicating the need for care in arriving at a definitive diagnosis.

Implant Treatment after Sagittal Splitting Ramus Osteotomy and Alveolar Ridge Augmentation in Patient with Mandibular Prognathism and Multiple Missing Maxillary Teeth.

An abnormal maxillomandibular ridge relationship frequently hinders oral implant treatment in patients with jaw deformities. Here, we describe a patient who was experiencing difficulty using dentures due to multiple maxillary tooth loss and mandibular prognathism. Treatment comprising sagittal splitting ramus osteotomy and alveolar ridge augmentation using bone grafts harvested from the mandibular ramus followed by implant treatment yielded good outcomes. The patient was a 47-year-old woman presenting with an unstable upper partial denture. Although prior prosthetic treatment for mandibular prognathism had resulted in normal overbite, she had since lost an increasing number of teeth due to advanced periodontal disease, impairing support for the denture. She was referred to the Department of Oral Implantology at the Tokyo Dental College Chiba Hospital in October 2008. Subsequent treatment comprised implant treatment following maxillary alveolar ridge augmentation and sagittal splitting ramus osteotomy to correct the maxillary-mandibular relationship. In January 2010, sagittal splitting ramus osteotomy and alveolar bone augmentation using a bone graft from the mandibular ramus were performed under general anesthesia. In July and August 2010, a total of 7 implants were placed in the maxilla and implant superstructure preparation started after 3 months. Taking both the patient's wishes and ease of maintenance into account, retrievable superstructures made of Auro Galvano Crown were fitted in April 2011. The jaw-to-jaw alveolar ridge relationship was improved by sagittal splitting ramus osteotomy, rendering subsequent treatment, from implant placement to superstructure preparation, feasible by conventional methods. The use of surplus bone generated during sagittal splitting ramus osteotomy for bone augmentation avoided the need to harvest bone from another area.

Congenital Epulis: A Case and Review of the Literature.

Congenital epulis is an unusual benign oral mucosal lesion in newborns with no tendency to recur after excision. The histogenesis of the lesion is unknown, but it is believed to be of mesenchymal origin. We describe a case of congenital epulis (20×10 mm) in the mandibular gingiva of a newborn. The mass, which was smooth-surfaced and pedunculated with a healthy color, was surgically removed at 5 months post-birth. Histologically, the tumor consisted mainly of large eosinophilic granular cells. Immunohistochemical studies revealed intense staining for vimentin, STRO-1, and CD44, suggesting that it was derived from mesenchymal cells. The literature and immunohistochemical profile of congenital epulis are also discussed.

Atypical MRI and Histopathological Findings in Dermoid Cyst.

On images, a dermoid cyst is often described as resembling a "sack of marbles" or "marbles in a bag". Typically, it comprises an inhomogeneity filled with multiple nodules in a fluid matrix on both computed tomography and magnetic resonance imaging (MRI). How it appears, however, will vary depending on its histological contents, which may cause confusion in arriving at a diagnosis. This report describes a dermoid cyst in the floor of the mouth of a 55 year-old woman that showed an atypical internal appearance on MRI. Most of the lesion showed homogeneous high signal intensity on T1 - and T2-weighted images, suggesting that it was derived from fat. A small area within the mass, however, showed moderate signal intensity almost equal to that of muscle on T1-weighted images and high signal intensity on fat-suppressed T2-weighted images. Given the location of the lesion, a dermoid cyst was one possible diagnosis. A lipoma or lipoma variants were also considered, however, based on signal intensity. Histopathological section of the excised specimen revealed a dermoid cyst with sebaceous glands in its walls and keratin in its cavity. Dermoid cysts show variation in their internal structures and contents. Since MRI can reflect such histological variation, signal intensity requires careful interpretation.

Antiresorptive agent-related osteonecrosis of the jaw: Position Paper 2017 of the Japanese Allied Committee on Osteonecrosis of the Jaw.

Antiresorptive agent-related osteonecrosis of the jaw (ARONJ) is an intractable, though rare, complication in cancer patients with bone metastases and patients with osteoporosis who are treated with antiresorptive agents, including bisphosphonates and denosumab. Despite the more than 10 years that have passed since the first cases of bisphosphonate-related osteonecrosis of the jaw (BRONJ) were reported, our understanding of the epidemiology and pathophysiology of ARONJ remains limited, and data supported by evidence-based medicine are still sparse. However, the diagnosis and staging of ARONJ, identification of risk factors, and development of preventive and therapeutic approaches have advanced significantly over the past decade. The Position Paper 2017 is an updated version of the Position Paper 2010 of the Japanese Allied Committee on Osteonecrosis of the Jaw, which now comprises six Japanese academic societies. The Position Paper 2017 describes a new diagnostic definition for ARONJ, as proposed by the American Association of Oral and Maxillofacial Surgeons (AAOMS), summarizes our current understanding of the pathophysiology of ARONJ based on a literature search, and suggests methods for physicians and dentists/oral surgeons to manage the disease. In addition, the appropriateness of discontinuing antiresorptive medications (drug holiday) before, during, and after invasive dental treatments is discussed extensively. More importantly, the manuscript also proposes, for the first time, the importance of interactive communication and cooperation between physicians and dentists/oral surgeons for the successful treatment of ARONJ. The Position Paper 2017 is intended to serve as a guide for improving the management of ARONJ patients in Japan.