Precise Coronoidectomy and Zygomatic Arch Reduction for Unilateral Hyperplasia of the Coronoid Process (Jacob's Disease) via Computer-aided Design and Manufacture.

Jacob disease is the new formation of a pseudo-joint between both of enlarged coronoid process and even zygomatic arch. A 23-year-old female patient with facial asymmetry and limited mouth opening was reported. Computed tomography images showed the classic symptom of Jacob disease with a mushroom-shaped tumor mass from the coronoid process a pseudoarthrosis joint with zygomatic arch. Coronoidectomy and zygomatic arch reduction were planned to operate based on computer-aided design/computer-aided manufacturing. During the actual operation, the excision of coronoid process and reconstruction of zygomatic arch were all navigated by 3-dimensional-printed surgical templates as designed through an intraoral approach. As a result, the enlarged coronoid process was smoothly removed without sequela and mouth opening along with facial symmetry were successfully improved. The authors suggested that computer-aided design/computer-aided manufacturing should be considered as an auxiliary technique to shorten operation time and enhance surgical accuracy.

Peripheral Osteoma of the Zygoma.

ABSTRACT: Osteoma is a benign, slow growing lesion that consists of compact or cancellous bone. Three types of osteomas could be classified: the central osteoma arising from the endosteum, the peripheral osteoma from the periosteum, and the extraskeletal soft tissue osteoma. in the craniofacial region, peripheral osteomas of the zygoma are quite rare. A literature review identified 7 cases of zygomatic arch and 3 cases of zygomatic body. This is the first report of zygomatic osteoma that was endoscopically removed. This report presents a rare case of osteoma of the zygoma and its endoscopic approach. The authors were able to confirm that endo-scopic approach of this zygomatic osteoma was safe and effective surgical choice.

Radiographic and CT features of zygomatic arch pneumatization in a Thoroughbred with a recurrent progressive ethmoid hematoma.

A 7-year-old Thoroughbred gelding presented with a history of mild unilateral right-sided epistaxis and facial swelling over the right caudal maxillary sinus and zygomatic arch. Eleven months previously a progressive ethmoid hematoma had been surgically removed from the right caudal maxillary and conchofrontal sinus. Computed tomography identified a large expansile soft-tissue attenuating mass in the right caudal maxillary sinus, with protrusion into the conchofrontal sinus, that extended into the zygomatic arch. Lytic expansion and thinning of the cortex with pneumatization of the zygomatic arch was present. The mass was surgically excised after a biopsy had confirmed the recurring progressive ethmoid hematoma.

Cryptococcal osteomyelitis of the Zygomatic bone: a case report.

BACKGROUND: Disseminated cryptococcosis is a well-characterized complication in immunocompromised patients with cryptococcal pneumonia or meningitis; however, isolated cryptococcal osteomyelitis is a rare entity that occurs in approximately 5% of patients with cryptococcosis. Cryptococcal osteomyelitis in the head and neck region is extremely rare. To the best of our knowledge, no cases of cryptococcal osteomyelitis affecting only the zygomatic bone have been reported to date. CASE PRESENTATION: A 78-year-old man without other comorbidities presented with progressive swelling of the right cheek along with pain and trismus. Clinical examination revealed a tender swelling in the right zygomatic region; the maximal mandibular opening was about 2 cm. Laboratory data showed mildly elevated inflammatory indices (C-reactive protein: 0.45 mg/dL; erythrocyte sedimentation rate: 35 mm/h). Computed tomography showed a 30-mm-diameter lesion at the right zygomatic arch. A part of the lesion has extended to the subcutaneous area of the cheeks with signs of bone destruction and surrounding contrast effects. Histopathological examination of fine-needle aspirate and needle biopsy showed cryptococcus. Furthermore, culture of the aspirate showed growth of Cryptococcus neoformans. No evidence of any other site involvement was observed. Therefore, the patient was diagnosed with isolated cryptococcal osteomyelitis and was initiated on fluconazole therapy. The treatment was effective, and all symptoms were resolved in 4 weeks. Fluconazole therapy was stopped after 6 months. There are no signs of recurrence as of 15-month follow-up. The patient has no cosmetic abnormalities or sequelae. CONCLUSIONS: Fine-needle aspiration cytology, needle biopsy, and fungal culture were useful for definitive diagnosis. Immunocompetent patients with isolated osteomyelitis may be cured with oral fluconazole alone.

Primary Epithelioid Sarcoma of the Zygomatic Bone.

Primary epithelioid sarcoma (ES) of bone is extremely rare with only 2 reported cases in the English literature. A previously healthy 18-year-old man presented with a 6-month history of right facial numbness and tingling and right eye diplopia. A computerized tomography scan revealed an ill-defined mass with dense osseous matrix centered in the right zygomatic bone. An outside biopsy was read as osteosarcoma. The resection specimen revealed large epithelioid and spindle cells embedded in a prominent hyalinized matrix with focal metaplastic bone formation. The tumor cells were strongly and diffusely positive for AE1/AE3 and epithelial membrane antigen, but a definitive diagnosis of ES was not immediately reached due to the presence of dense hyalinized matrix and weak expression of SAT2B by tumor cells. Deficient INI1 protein expression by immunohistochemistry and homozygous loss of the SMARCB1 gene by chromosomal microarray analysis ultimately justified this tumor's designation as ES.

Zygomatic Arch Parosteal Osteosarcoma in Dogs and a Cat.

Parosteal osteosarcoma is a rare, slow-growing tumor most commonly arising from the surface of long bones. Tissue or histological sections from 5 dogs and 1 cat with zygomatic arch masses were examined. Clinical presentations varied from chronic sneezing to facial swelling. Imaging consistently demonstrated osseous proliferation in the area of the zygomatic arch. Histologically, the masses were characterized by well-differentiated fibro-osseous and chondroid components that radiated outward from the periosteum of the zygomatic bone. Cellular atypia and mitotic figures were uncommon. Parosteal osteosarcomas have previously been reported in the skulls of dogs and cats, but only 1 has been reported on the zygomatic arch. Initially, these tumors are of low histologic low grade, but with time, they can show more aggressive behavior and invade the underlying bone.

Surgical Management of a Recurrent Odontogenic Keratocyst With Orbital and Temporal Fossa Invasion.

Odontogenic keratocyst is a benign locally aggressive odontogenic cyst with a high recurrence rate. This report presents an unusual case of a recurrent odontogenic keratocyst with zygomatic bone involvement and orbital and temporal extension resulting in globe compression. Odontogenic keratocyst is reviewed, and surgical management of the cyst is discussed.The authors present a case of a recurrent odontogenic keratocyst involving the zygoma with orbital and temporal invasion; aggressive surgical resection and reconstruction was required.

Modified lateral orbitotomy with combined partial zygomatic arch and vertical ramus ostectomies for excision of a frontal and parietal bone osteoma in a dog.

OBJECTIVE: To describe modifications to the lateral orbitotomy for surgical excision of tumors affecting the frontal, parietal, palatine, or temporal bones. STUDY DESIGN: Case report. ANIMAL: A 5-year-old female spayed American pit bull terrier. METHODS: The dog presented for excision of a bone tumor affecting the right frontal and parietal bones. A modified lateral orbitotomy was performed with combined partial zygomatic arch and vertical ramus ostectomies to increase working space and allow drilling of the calvarium ventral to the mass. RESULTS: The dog tolerated the procedure well, and there were no complications from either the ostectomies or the craniectomy. Histopathological examination was consistent with complete excision of an osteoma. The dog survived 2 years with no recurrence and was euthanized due to an intestinal mass. CONCLUSION: The lateral orbitotomy approach can be modified with combined partial zygomatic arch and vertical ramus ostectomies to increase exposure and working space for resection of tumors affecting the frontal, parietal, palatine, or temporal bones.

Outcome of treatment of Zygomatic bone fracture by two point fixation versus three point fixation in Mayo Hospital Lahore.

OBJECTIVE: To compare the outcome of two-point internal fixation versus three-point internal fixation for the treatment of zygoma fractures. METHODS: The quassi-experimental study was conducted at the King Edward Medical University, Mayo Hospital, Lahore, Pakistan, from April to September 2016, and comprised patients with zygomatic bone fracture who were randomly divided into two groups. In Group A, patients were treated with two-point fixation and in Group B, patients were treated with three-point fixation. All patients were treated by the same consultant. Patients were followed up on first, third and sixth week postoperatively and malar height and mouth opening were recorded at the sixth week follow-up. Data was analysed using SPSS 17. RESULTS: Of the 60 patients, there were 30(50%) in each of the two groups. There were 39(65%) males and 21(35%) females. The mean age in Group A was 29.56±9.89 years (range: 17-50 years), while in Group-B it was 29.45±8.68 years (range: 17-49 years). Mean malar height at 6th week post-operative follow up showed a significant reduction in Group B compared to Group A (p= 0.001). Significant improvement in mouth opening was seen in Group B compared to Group A (p= 0.034). CONCLUSIONS: Three-point fixation was found to give more stable reduction compared to 2-point fixation for treating zygomatic bone fractures in terms of malar height and mouth opening.

Mutations in the endothelin receptor type A cause mandibulofacial dysostosis with alopecia.

The endothelin receptor type A (EDNRA) signaling pathway is essential for the establishment of mandibular identity during development of the first pharyngeal arch. We report four unrelated individuals with the syndrome mandibulofacial dysostosis with alopecia (MFDA) who have de novo missense variants in EDNRA. Three of the four individuals have the same substitution, p.Tyr129Phe. Tyr129 is known to determine the selective affinity of EDNRA for endothelin 1 (EDN1), its major physiological ligand, and the p.Tyr129Phe variant increases the affinity of the receptor for EDN3, its non-preferred ligand, by two orders of magnitude. The fourth individual has a somatic mosaic substitution, p.Glu303Lys, and was previously described as having Johnson-McMillin syndrome. The zygomatic arch of individuals with MFDA resembles that of mice in which EDNRA is ectopically activated in the maxillary prominence, resulting in a maxillary to mandibular transformation, suggesting that the p.Tyr129Phe variant causes an EDNRA gain of function in the developing upper jaw. Our in vitro and in vivo assays suggested complex, context-dependent effects of the EDNRA variants on downstream signaling. Our findings highlight the importance of finely tuned regulation of EDNRA signaling during human craniofacial development and suggest that modification of endothelin receptor-ligand specificity was a key step in the evolution of vertebrate jaws.

Analysis of Facial Symmetry After Zygomatic Bone Fracture Management.

PURPOSE: The location of the zygomatic bone plays an important role in facial symmetry and esthetics. The aim of this study was to determine and compare the frequency of facial asymmetry in a sample of patients who had undergone treatment of unilateral zygomaticomaxillary complex (ZMC) fractures (study group) and a sample of patients without ZMC fracture (control group). MATERIALS AND METHODS: This was a retrospective controlled cross-sectional study. The primary predictor variable was the type of ZMC fracture (linear or comminuted). The primary outcome variable was facial asymmetry characterized by the bilateral difference in the position of the malar eminence (ME) in 3 dimensions based on computed tomographic images. The other variables for this study were classified as demographic (age and gender) and anatomic (side of ZMC fracture). Descriptive and bivariate statistics were computed. Statistical significance was set at a P value less than .05 with 95% reliability. RESULTS: The entire sample consisted of 134 patients (n = 67 per group). The mean bilateral difference of the ME position in the study group was markedly greater than in the control group. More than half the study patients had facial symmetry and almost 10% of them had marked asymmetry, whereas none of the control patients had marked asymmetry. All patients with marked asymmetry and approximately 70% of them with greater than maximum normal asymmetry had a comminuted fracture. CONCLUSIONS: The results of this study show that although the frequency of facial asymmetry in patients with ZMC fracture was higher than in the control patients, it was found in all patients to a certain extent. Patients' awareness of this fact can decrease their dissatisfaction.

Odontogenic parakeratinized cyst resulting in exophthalmos and palatine, maxillary, and zygomatic bone erosion in a dog.

A novel case of a canine odontogenic parakeratinized cyst (COPC) that resulted in exophthalmos and palatine, maxillary, and zygomatic bone erosion in a 5-year-old Chihuahua dog is reported. Final diagnosis was aided by cross-sectional imaging (magnetic resonance imaging and computed tomography) and confirmed with histologic examination of the cyst wall.

Temporal Progression of Craniofacial Dysmorphology in Unilateral Coronal Synostosis: A Mechanistic Hypothesis.

AIM: This study chronicles skull base and face development in nonsyndromic unilateral coronal synostosis (UCS) during infancy, to characterize the mechanistic progression of facial dysmorphology. METHODS: Computed tomography scans from 51 subjects were reviewed (26 UCS, 25 controls) and data were reconstructed. Patients were stratified into 5 age groups. A series of measurements were taken from the reconstructions. RESULTS: All patients had a unilaterally fused coronal suture at the time of analysis. Asymmetry of the sphenoid wings was present across all age groups. The sphenoid wing ipsilateral to the fused suture consistently had a more acute angle from the midline. At 19 days of age, ipsilateral nasal root and cribriform plate deviation are noted, as well as increased contralateral zygoma antero-posterior length. Patients younger than 2 months also had elongated posterior cranial bases. At 2 to 3 months of age, the cranial base widens in the anterior portion of the middle cranial fossa with an increased ipsilateral pterion to sella distance. The most delayed change observed was the increase in contralateral orbital rim angle at 7 to 12 months of age compared to normal. CONCLUSION: After suture fusion, sphenoid wing changes are among the earliest restructural malformations to take place. This suggests that the cascade of dysmorphology in UCS originates in the cranial vault, then progresses to the skull base, and lastly to the facial structures. Ipsilateral orbital changes are early facial changes in UCS that begin before 2 months of age. This is then followed by changes in the contralateral face later in development.

Alveolar bone changes after rapid maxillary expansion with tooth-born appliances: a systematic review.

Background: During rapid maxillary expansion (RME), heavy forces are transmitted to the maxilla by the anchored teeth causing buccal inclination and buccal bone loss of posterior teeth. Objective: To systematically review the literature in order to investigate whether RME causes periodontal sequelae, assessed by cone-beam computed tomography (CBCT). Search methods: Fifteen electronic databases and reference lists of studies were searched up to March 2017. Selection criteria: To be included in the systematic review, articles must be human studies on growing subjects, with transversal maxillary deficiency treated with RME and with assessment of buccal bone loss by CBCT images. Only randomized and non-randomized trials were included. Data collection and analysis: Two authors independently performed study selection, data extraction, and risk of bias assessment. Study characteristics (study design, sample size, age, sex, skeletal maturity, type of appliance, daily activation, evaluated linear measurements, observation period, CBCT settings), and study outcomes (loss of buccal bone thickness and marginal bone) were reported according to the PRISMA statement. Results: On the basis of the applied inclusion criteria, only six articles, three randomized clinical trials and three controlled clinical trials were included. An individual analysis of the selected articles was undertaken. The risks of bias of the six trials were scored as medium to low. Limitations: The results of the present systematic review are based on a limited number of studies and only one study included a control group. Conclusions and implications: In all considered studies, significant loss of buccal bone thickness and marginal bone level were observed in anchored teeth, following RME. Further prospective studies correlating the radiological data of bone loss to the periodontal soft tissues reaction after RME are required. A preliminary evaluation of the patient-related risk factors for RR may be advisable when considering to administering RME. Registration: This systematic review was registered in the National Institute of Health Research database with an appropriate protocol number (http://www.crd.york.ac.uk/PROSPERO Protocol: CRD42017062645). Funding: The present study has not received any contributions from private or public funding agencies.

Hemangioma of the Zygomatic Bone.

Benign masses arising from facial bones have been reported several times in the literature. Hemangiomas are one of the uncommon benign tumors. In this study, the authors aimed to present a rare patient of zygomatic intraosseos hemangioma and their management. A 40-year-old woman with a mass in her left lateral cantus admitted to our clinic. Preoperative computed tomography and magnetic resonance imaging revealed an osseos mass in her left zygoma. The authors conclude that it should be kept in mind that although they are very rare benign tumors, intraosseos hemangiomas can cause facial masses. Meticulous radiologic examination can give important clues for differential diagnosis before the surgery.

Bone Resection Versus Setback in Reduction Malarplasty: A Quantitative Analysis of the Migration of the Summit of the Zygoma.

BACKGROUND: We hypothesized that the amount of bone resection and setback together controls the effect of reducing the zygomatic body during reduction malarplasty; however, quantitative analyses of this movement are lacking. METHODS: A retrospective study of patients who underwent reduction malarplasty between Aug. 2013 and Jan. 2015 was performed. We used 3-dimensional computed tomography (3D CT) scanning to measure movements of the summit of the zygoma (SOZ). We analyzed 394 zygomas in 197 patients. RESULTS: The bone resection amount was not significantly correlated with the anteroposterior movement of the SOZ (p = 0.270); in contrast, the setback amount, was significantly correlated with anteroposterior SOZ movement (p < 0.001). The bone resection amount was not correlated with cephalocaudal movement (p = 0.158); however, cephalocaudal movement was significantly correlated with the setback amount (p < 0.001). Both the bone resection amount and the setback amount were correlated with mediolateral movement (p < 0.001). The amount of bone resection determined the mediolateral movement. Both the bone resection amount and the setback amount were correlated with the mean movement distance of the SOZ (p < 0.001). Both the R (2) (0.704 > 0.084) and ß (0.839 > 0.290) values indicated that the setback amount made a larger contribution to the SOZ movement distance than did the bone resection amount. CONCLUSIONS: Whereas bone resection was the major factor in the medial movement of the SOZ, bone setback was the major factor in the anterior and superior movement of the SOZ and a minor factor in the medial movement. The results indicate that both bone reposition and bone resection are important factors in maximizing surgical results of the reduction malarplasty. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Ultrasonographic imaging of the temporomandibular joint in healthy cattle and pathological findings in one clinical case.

AIMS: To describe the normal ultrasonographic appearance of the temporomandibular joint (TMJ) in cattle, and to describe the ultrasonographic pathology of the TMJ as assessed in one cow with TMJ disease. METHODS: The TMJ of 12 healthy Holstein-Friesian cows were examined using a portable ultrasonographic unit with a 7.5 MHz linear probe and a 6.0 MHz convex probe. Each TMJ was scanned in a rostrolateral, lateral and caudolateral plane. In addition, the TMJ of one 2-year-old cow with clinical signs of food retention in the mouth, head tilt, swelling and pain in the right TMJ region and an infected horn fracture was examined ultrasonographically. RESULTS: The bone surfaces of the temporal process, the zygomatic process and the temporal bone, the larger muscles of the TMJ region, the superficial temporal vein, and the parotid salivary gland could be imaged in all normal healthy cattle. Using the linear probe, the joint capsule was visible in 17/24 (71%) cases in the caudolateral plane, but the articular disc could not be visualised. With the convex probe, the joint capsule could be imaged in all cases in the caudolateral plane, and the articular disc in 13/24 (54%) cases in the caudolateral plane. It was never possible to see the synovial pouch in healthy cattle using either probe. By contrast, in the cow diagnosed with septic arthritis of the right TMJ, a marked anechoic and heterogeneous hypoechoic effusion of the TMJ with distension of the joint capsule was visualised. CONCLUSIONS: The results of this descriptive study serve to provide a reference for ultrasonography of pathological conditions of the TMJ region in cattle. CLINICAL RELEVANCE: As many veterinarians are equipped with ultrasound machines with 5-8 MHz linear rectal probes, the authors recommend using these probes for further investigation of clinical cases with swelling of the TMJ region and/or masticatory problems of unclear origin to exclude or diagnose TMJ disorders.

An unusual case of desmoplastic melanoma containing an osteoclast-like giant cell-rich nodule.

The authors describe a case of a 5 cm mixed desmoplastic melanoma occurring on the cheek of an 88-year-old white woman. The epidermis showed the features of lentigo maligna. Within the dermis, there was a mixed desmoplastic melanoma with 2 components. The first component consisted of infiltrative malignant spindled cells with prominent stromal fibrosis and had the typical appearance of desmoplastic melanoma. The second component was within the deep half of the tumor and consisted of a densely cellular nodule composed of spindled melanocytes admixed with many osteoclast-like giant cells. There was a peripheral neurotropism and tumor invaded bone. The Breslow thickness was 14 mm. On followup, a sacral metastasis was discovered, which had a similar morphology to the deep cellular nodule. Immunohistochemistry of spindled cells both inside and outside the nodule showed S100 positivity with the absence of other melanocytic markers (HMB-45, Melan-A). Smooth muscle actin and p63 were focally positive. The osteoclast-like giant cells expressed CD68 and MiTF. Array comparative genomic hybridization of the typical desmoplastic melanoma region had a flat profile, whereas the cellular osteoclast-like giant cell­rich region displayed important cytogenetic anomalies, some of which have been previously described in melanomas. The main array comparative genomic hybridization findings were confirmed by fluorescence in situ hybridization using specific probes. The differences in morphology and molecular cytogenetics between the 2 areas suggest that these might represent the progression or emergence of a more aggressive clone within the tumor. Subsequent metastatic spread to the bone may be a result of accumulated cytogenetic abnormalities.

Phenotype-genotype correlations of facial width and height proportions in patients with Class II malocclusion.

OBJECTIVES: To characterize soft-tissue facial height and width variation in Class II malocclusion and test for correlations with genes HMGA2, AJUBA, and ADK. SETTING AND SAMPLE POPULATION: Nine facial proportions were estimated from 2D frontal repose photographs of 330 Caucasian adults with Class II malocclusion. MATERIAL AND METHODS: After adjustments for age and gender, the facial proportions were submitted to a principal component analyses (PCA). The most meaningful phenotypic variations were correlated with SNPs rs7924176 (ADK), rs17101923 (HMGA2), and rs997154 (AJUBA) genotyped in 106 individuals. RESULTS: Principal component analyses resulted in four principal components (PCs), which explained 75% of total variation. PC1 captured variation in the intercanthus distance and explained 28% of total variation. PC2 explained 21% of the variations in facial taper and facial index. PC3 explained 14% and reflected variations in the vertical dimension of the lower face. PC4 explained 12% and captured variations in distance between the eyes, width of the commissures, and the length of the superior aspect of the lower face height corresponding to the vertical dimension of the philtrum of the upper lip. A suggestive association (p<0.05) was observed between PC4 and rs997154 corroborating the role of AJUBA in variation of facial dimensions. CONCLUSION: 2D frontal photographs can be used to derive quantitative measures of soft-tissue phenotypes that are of clinical relevance. The methods described are suitable for discovery and replication of associations between genotypes and malocclusion phenotypes.