Zygomatic bone metastasis from hepatocellular carcinoma and the therapeutic efficacy of apatinib: A case report and literature review.

RATIONALE: Hepatocellular carcinoma (HCC) metastases to the zygomatic bone are extremely uncommon, and the treatment of target drugs against such case is unknown. PATIENT CONCERNS: A 48-year-old male patient was admitted to our hospital under suspicion of an advanced liver tumor due to an increase in levels of alpha-fetoprotein (AFP) after radiofrequency ablation for independent nodule in his liver 1 month before. He had a hepatitis B virus (HBV) history for 20 years without treatment. DIAGNOSIS AND INTERVENTIONS: A diagnosis of primary HCC was made based on pathological examination following right hepatectomy. Seven months after the surgery, a mass in S8 was identified and treated by ARF. Twenty days later, a right zygomatic mass was observed and the incisional biopsy revealed metastasis from HCC. Due to side effects of chemotherapy, the metastatic zygomatic mass was treated with radioactive seed implantation. Despite these interventions, there was steady increase in AFP values as well as increase in size of the zygomatic mass. Hence, the patient was started on apatinib with a dose of 500 mg/day from 1 to 28 days per cycle for a duration of 10 months. OUTCOMES: The AFP values were significantly decreased but the size of the zygomatic mass continued to increase indicating progression of disease. But the progression-free survival was more than 10 months. The patient exhibited adverse reactions which were controllable by symptomatic treatments. As of last follow-up, the patient is unwell with pain in the face, blurred vision in the right eye, dyscrasia, and exhibited difficulty in opening his mouth. LESSONS: HCC metastases to the zygomatic bone are very aggressive with a very low incidence and immunohistochemistry is useful diagnostic indicators. Still now, there is no optimal treatment strategy for these patients. Apatinib may be a promising drug in the treatment of HCC metastases to the zygomatic bone.

Biologic Behavior of Hydroxyapatite Used in Facial Augmentation.

INTRODUCTION: The recent finding that shrinkage of key areas of the facial skeleton contributes to the aging appearance of the face has prompted a search for the most appropriate bone-like implant material. Evidence that hydroxyapatite, in granular form, maintains volume in the long term supports its use in the correction of aging, in addition to its use in the correction of inherently deficient areas of the facial skeleton. The biologic response of hydroxyapatite needs to be fully understood for its use to be confidently recommended. MATERIALS AND METHODS: Samples of 'living' hydroxyapatite from the anterior maxilla, zygoma, and mandible of 17 patients were analyzed. These were obtained during revision procedures performed between 6 months and 15 years following original placement on the facial skeleton. RESULTS: Histology showed that in every case, the individual granules were embedded within a mass of collagen that made up about half of the total implant volume. The collagen mass also contained fine elastin, fibroblasts, lymphocytes, occasional granulomas, and vessels. By 2 years, a new compact bone containing osteoblasts and osteocytes was present in all specimens in the deep (osseous) aspect. Bone progressively replaced the original collagen between the granules with a sharply defined transition at the interface. CONCLUSIONS: This study confirmed a two-stage biologic change following onlay placement of hydroxyapatite granules on the facial skeleton, i.e., initial collagen formation with subsequent conversion to bone. This integrates the implant with the host bone which stabilizes the implant position and shape initially and in long term. NO LEVEL ASSIGNED: 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 .

The Effects of Desferroxamine on Bone and Bone Graft Healing in Critical-Size Bone Defects.

BACKGROUND: Autogenous bone grafts are still the criterion standard treatment option in critical-size bone defect reconstructions, and many therapies can affect its incorporation. In this study, it was aimed to research the effects of desferroxamine (DFO) application on bone and bone graft healing due to the effects of osteoblast and osteoclast regulation and stimulation of angiogenesis. METHODS: Rat zygomatic arch critical-size bone defect model (5 mm) was used as the experimental model. Thirty-two Sprague-Dawley rats (64 zygomatic arches) were divided into 4 groups (16 zygomatic arches in each). In groups 1 and 2, defects were reconstructed with the bone grafts harvested from the other side, and the right arc was named as group 1, and the left was group 2. At group 1, 200 µM/300 µL dosage of DFO was injected at the zygomatic arch region starting at the seventh day preoperatively and lasting until the 45th day postoperatively. Group 2 animals were defined as the control group of group 1, and 0.9% NaCl injection was applied. In groups 3 and 4, there was no repair after the formation of defects, and the right arc region was treated with DFO, and left was treated with 0.9% NaCl for postoperative 45 days, respectively. Radiological (computed tomography), histological (hematoxylin-eosin), and biomechanical (3-point bending test) tests were used for the evaluation. RESULTS: In radiological evaluation, there was a statistically significant decrease (P < 0.05) in bone defect size in group 3 animals at the 4th, 8th, and 12th weeks, and bone graft volume showed a statistical difference at all weeks (P < 0.05). In histological evaluation, it was observed that there was an increase in osteoblast number and vascularity rates (P < 0.05) in the DFO-treated groups at all weeks. Biomechanical evaluation of the subjects showed increase in bone strength in group 1 animals at 12 weeks. CONCLUSIONS: In this study, it was shown that DFO treatment increased bone graft incorporation and healing in critical-size bone defects. In this aspect, we suggest that DFO can be used to increase graft incorporation in risky areas and reduce the defect size in patients who are not suitable for vascularized bone graft transfer.

[Zygomatic localization of Langerhans cell histiocytosis - a case report].

Langerhans cell histocytosis is a rare disease. LCH is reported mainly in children aged less than 15 years, however it may appear at any age. In this work, the case of 17-month boy is reported. The boy was admitted to the pediatric ophthalmology department in order to diagnose the swelling and bruising in the lower part of left orbit, which had lasted for one month before. The clinical status, various imaging techniques' results (MRI, TK and PET) and immunohistochemistry led to the final diagnosis of multisystem LCH (spread to masticator muscle and zygomatic bone). After the pharmacological therapy the total remission was achieved. Since four years the child is regularly controlled by oncologists and hematologists with no relapse reported.

Denervation and beta2-adrenoceptor-agonist administration on craniofacial bone density.

OBJECTIVE: Beta2-agonist medications are thought to have adverse effects on bone density. Surgical denervation and intramuscular beta2-agonist injections appear to have opposing effects on skeletal muscles. The present study has been designed to assess the effects of denervation of the masseter, intramuscular injection of a beta2-agonist and the combination of both procedures, on bone density in the craniofacial skeleton in rats. MATERIALS AND METHODS: Sprague-Dawley rats were prepared as four groups: 1. surgical sham + saline injection into the masseter (sham); 2. surgical denervation of the masseter (den.); 3. surgical denervation of the masseter + intramuscular formoterol injection into the affected muscle (den.+form.); 4. intramuscular formoterol injection into the masseter (form.). All specimens were submitted for CT examination and volumetric calculations of the mineralised bone tissue were performed. RESULTS: The sham and form. groups had a greater volume of mineralised bone in the zygoma on the experimental side compared with the control side. The maxilla on the experimental side had a higher volume of mineralised bone in the den.+form. and form. groups compared with the sham and den. groups. The control side of the maxilla had a higher volume of mineralised bone in the den.+form. and form. groups compared with the den. group only. CONCLUSION: Intramuscular administration of formoterol appears to induce a bilateral increase in bone mineral density in the maxilla and the zygoma, likely explained as a secondary effect of the well-described increase in muscle mass and strength associated with beta2-agonist administration.

The effects of denervation and formoterol administration on facial growth.

OBJECTIVE: To identify and demonstrate possible alterations of skeletal structures which might follow either unilateral surgical denervation of the masseter muscle, unilateral intramuscular injection of formoterol directly into the masseter muscle, or intramuscular formoterol injection after surgical denervation. MATERIALS AND METHODS: Male Sprague Dawley rats (N = 16; four weeks of age) were prepared as four groups: 1. surgical sham + saline injection into the masseter muscle (sham); 2. surgical denervation of the masseter muscle only (den.); 3. surgical denervation of the masseter muscle plus intramuscular formoterol injection into the affected muscle (den.+form.); 4. intramuscular formoterol injection into the masseter muscle only (form.). The specimens were submitted for CT examination, the skulls and hemimandibles were photographed and measurements of craniofacial bones were made. RESULTS: In this relatively small sample, comparisons between non-experimental and experimental sides revealed differences, both within the groups and for the same measurements between groups, with the den. and den.+form. groups showing the most change. Relative increases in the gonial angle shown in these groups occurred bilaterally, with the change on the experimental side always greater in magnitude than the change on the contralateral side. CONCLUSIONS: Surgical denervation of the masseter muscle leads to an alteration in the size and shape of the skeletal structures close to the zygoma and the mandible. The intramuscular injection of formoterol into denervated masseter muscle seems to limit this skeletal alteration after surgical denervation.

Radiation-induced craniofacial bone growth inhibition: acute and long-term effects on bone histopathology with and without cytoprotection.

BACKGROUND: The authors previously established an animal model of radiation-induced craniofacial bone growth inhibition and demonstrated the effectiveness of cytoprotection in preserving growth using amifostine, but the mechanism is unclear. The objective of this study was to investigate the acute and long-term histopathologic effects of single-dose orthovoltage irradiation on craniofacial bone with and without cytoprotection. METHODS: Sixty infant New Zealand White rabbits (7-week-old) were randomized into three groups (n = 20 per group): group 1, 0-Gy, sham irradiation; group 2, 35-Gy single-dose orthovoltage irradiation; and group 3, cytoprotection with amifostine before irradiation. Orbitozygomatic complex bone was harvested from animals 12 hours after irradiation and at skeletal maturity (21 weeks of age). Histologic parameters measured included native bone cell (osteoblast, osteoclast, and osteocyte) populations, periosteal proliferation indices (MIB-1 stains), bone turnover rates [triple fluorochromes: tetracycline administered at 7 weeks of age (before irradiation), alizarin complexone at 12 weeks, and calcein at 16 weeks of age], and endosteal space fibrosis levels. RESULTS: Orthovoltage irradiation significantly (p < 0.05) reduced osteoblast and osteoclast counts 12 hours after irradiation (age, 7 weeks) with or without pretreatment with amifostine but had no effect on osteocyte populations. Long-term analysis at age 21 weeks demonstrated significantly (p < 0.05) increased osteoblast counts, reduced endosteal space fibrosis, reduced periosteal proliferation indices, and improved bone turnover (fluorochrome stains) in amifostine-treated animals. CONCLUSION: This study suggests that amifostine cytoprotection is mediated through a combination of reduced cellular injury with enhanced promotion of cellular bone rebuilding potential.

The healing of critical-sized bone defect of rat zygomatic arch with particulate bone graft and bone morphogenetic protein-2.

For some critical-sized bony defects in the facial bones, it is necessary that the defect be reconstructed using an autologous bone graft from another donor site, not only to ensure stability, but also to derive aesthetic contouring. However, because of the easy gain and easy moulding of particulate bone, it would be easier to reconstruct the defect by using particulate bone graft (PBG) rather than block bone graft (BBG). This study was designed to confirm the usefulness of PBG with bone morphogenetic protein-2 (BMP-2) instead of BBG and to observe its long-term outcome in critical-sized zygomatic arch defects in a rat model. A sample of 18 Sprague-Dawley rats was divided into three groups; a 5-mm critical-sized bone defect was made in both zygomatic arches of all subjects. Each group was treated with different combinations of BMP-2 and PBG. At 2, 4, 8 and 12 weeks after treatment, each defect was compared radiologically. Histological evaluation was performed after 12 weeks. In the first group, the defects with PBG decreased more than in those with no bone graft (P<0.01). In the second group, defects with PBG and BMP-2 decreased more than in those with PBG alone (P<0.01). In the third group, there was no significant difference between the group with PBG and BMP-2 and that with in situ bone graft (instead of BBG). In conclusion, PBG with BMP-2 showed satisfactory bone healing without any additional bone graft in the animal model.

Radiation-induced craniofacial bone growth inhibition: in vitro cytoprotection in the rabbit orbitozygomatic complex periosteum-derived cell culture.

BACKGROUND: Radiotherapy for the management of head and neck cancer in pediatric patients results in severe inhibition of craniofacial bone growth. Previously, the infant rabbit orbitozygomatic complex was established as an experimental model. Amifostine, a cytoprotective agent, was found effective in preventing radiation-induced bone growth inhibition. This study was designed to investigate the effects radiation on osteogenic cells from infant rabbit orbitozygomatic complex periostea and to assess the effects of cytoprotection in vitro. METHODS: Infant New Zealand White rabbits (n = 18) were randomized into three groups and received radiation (0, 10, or 15 Gy) to both orbitozygomatic complexes. Cell cultures were developed from orbitozygomatic complex periostea, and cell numbers, proliferation, alkaline phosphatase, and collagen type I expression and mineralization were assessed. Subsequently, rabbits (n = 18) were randomized into three groups to receive either radiation at the effective dose, pretreatment with amifostine (300 mg/kg, intravenously, 20 minutes before irradiation) with the effective radiation dose, or no treatment. Cell cultures were developed and tested for proliferation and alkaline phosphatase expression. RESULTS: Irradiation resulted in a significant inhibition of cell numbers (p < 0.001) and proliferation (p < 0.01) at the 15-Gy dose and no statistically significant changes in alkaline phosphatase activity. Collagen type I expression and mineralization were also significantly reduced at the 15-Gy dose. Pretreatment with amifostine significantly (p < 0.05) enhanced the number of surviving cells. CONCLUSIONS: Amifostine is capable of protecting orbitozygomatic complex periosteum-derived osteogenic cells from the deleterious effects of radiation. This study provides the basis for understanding the cellular mechanisms of radiation-induced craniofacial bone growth inhibition and cytoprotection by amifostine.

Efficacy of radioprotection in the prevention of radiation-induced craniofacial bone growth inhibition.

It has been reported that radiotherapy-induced craniofacial deformities can occur in 66 to 100 percent of survivors of childhood head and neck cancers. Recent interest in the effectiveness of radioprotectors in the protection of normal tissue against radiation injury led us to investigate a possible role of radioprotection in the prevention of radiation-induced craniofacial bone growth inhibition. Therefore, the objective of this study was to use the radioprotective agent amifostine (Ethyol, WR-2721) as a probe to determine the effectiveness of radioprotection in the prevention of radiation-induced craniofacial bone growth inhibition after single-dose orthovoltage radiation to the infant rabbit orbital-zygomatic complex. Seven-week-old male New Zealand white rabbits were randomized into three groups (n = 10 each): group 1, 0 Gy (sham radiation); group 2, 35-Gy single-dose orthovoltage radiation; and group 3, 35-Gy single-dose orthovoltage radiation and amifostine (300 mg/kg intravenously, given 20 minutes before radiation). Serial radiographs and computed tomographic scans were obtained for cephalometric analysis, bone volume, and bone density measurements until skeletal maturity at 21 weeks. Significant (p < 0.05) reductions in orbital-zygomatic complex linear bone growth, bone volume, and bone density were observed after 35-Gy radiation compared with nonirradiated controls. No significant differences were noted between groups in cephalometric analysis of the nontreated (nonirradiated) left orbital-zygomatic complex, indicating no crossover effect from the radiation beam. However, pretreatment with amifostine, 20 minutes before 35-Gy radiation, resulted in significant (p < 0.05) preservation of linear bone growth, bone volume, and bone mineral density in the rabbit orbital-zygomatic complex compared with controls. This study demonstrated for the first time the effectiveness of a radioprotector in the prevention of radiation-induced craniofacial bone growth inhibition, and it paves the way for investigation into the pathogenic mechanism and prevention of radiotherapy-induced craniofacial deformities.

Bone gap healing in the dog using recombinant human bone morphogenetic protein-2.

PURPOSE: This study investigated bone gap healing in a zygomatic arch defect using recombinant human bone morphogenetic protein-2 (rhBMP-2; Genetics Institute, Andover, MA) in an absorbable collagen sponge (ACS) carrier. METHODS: Zygomatic arch osteotomies were completed 15 mm apart and the arch was mobilized in 6 adult female mongrel dogs. The segment was then repositioned laterally 8 to 10 mm and secured with a titanium reconstruction plate. Bone gaps in either the right or left arches received rhBMP-2, with the contralateral side being left empty in 4 animals and the defects received buffer/ACS without rhBMP-2 in 2 animals as controls. Submentovertex radiographs were taken immediately postoperatively and every 4 weeks until killing at 12 weeks. RESULTS: Clinical evaluation indicated no significant differences in the degree of inflammation between the groups. However, the rhBMP-2 sites were found to be firm on palpation, in contrast to a soft tissue defect palpated in the control sites. Radiographic examination showed significant bone formation in all rhBMP-2 grafted sites as early as 4 weeks. The radiopacity of the bone continued to increase over the time of this study. Five of six control sites did not show bone formation through the course of this study. In addition to lack of bone formation, 5 of 6 control sites showed collapse of the repositioned arch. All arches in the rhBMP-2 sites remained in their lateral position and formed bone in the gaps. In 2 animals, bone formation moderately exceeded the confines of the gap, and in 2 animals excessive bone formation occurred. CONCLUSIONS: This study confirms that rhBMP-2 has the potential to be used to stimulate bone gap healing in the craniofacial complex.

Teratological studies on craniofacial malformations.

Craniofacial malformations cause great human suffering. The purpose of the experimental studies was to investigate teratogenically induced craniofacial malformations in the rat, and to study if vitamin B6 could prevent the teratogenically induced malformations in the rat. The aim of the clinical investigation was to compare mandibulofacial dysostosis (MFD) with hemifacial microsomia (HFM) and thalidomide-induced malformations restricted to the first and second branchial arches. In the experimental studies we used two different teratogenic agents, etretinate and BAPN (beta-aminoproprionitrile). Vitamin B6 was administered one day prior to and simultaneously with the teratogenic agent. The induced malformations were observed by direct microscopy, histology, differential staining, microdissection and enzyme histochemistry. Knowledge of isoenzymic differentiation was obtained by isoelectric focusing and polyacrylamide gel electrophoresis. The clinical features of 29 patients with MFD, 26 with HFM and seven with thalidomide-induced malformations were investigated. The patients underwent clinical investigations, radiography, tomography, computed tomography, surgical exploration and audiograms. The etretinate-induced syndrome in the rat shows similarities to first and second branchial arch syndromes in man. Defective formation of Meckel's cartilage and the cartilaginous skull base, the zygoma and the middle ear ossicles were prominent features of the observed malformations. The induced malformations were accompanied by increased staining for alkaline phosphatase (APase) in the skull and skull base cartilages and Meckel's cartilage. BAPN induced cleft palate in 95% of the cases and the teratogenically induced cleft palate was accompanied by a pathological differentiation pattern that could be traced by determination of isoenzymes in the palatal shelves as well as in amniotic fluid. Vitamin B6 could prevent the teratogenic malformations induced by etretinate and BAPN in the rat. Comparing MFD, HFM and thalidomide-induced malformations, all syndromes included patients with external, middle and inner ear malformations. Cranial nerve palsy/paresis was only seen in HFM and thalidomide-induced malformations. A relationship between disturbed neural crest cell migration and defects of the first and second branchial arches seems possible.