Osteosarcoma ( OS) is the most common primary malignant bone tumor in children and adolescents. Currently, the combination of surgical resection and chemotherapy is the main method of treatment for OS in the clinic.Al-though, the survival rate has been greatly improved in OS patients with localized disease, the 5-year survival rate has re-mained <20%.It is very important to understand the cause of disease, to develop novel drugs or therapeutics, and to learn the disease through animal models.This review will introduce the progress of animal models of osteosarcoma over the last years.

Objective To investigate the imaging features of the calvarial cavernous hemangioma and the surgical efficacy to improve diagnosis and treatment of the calvarial cavernous hemangioma.Methods The clinical information,imaging materials and surgical efficacy from ten cases of calvarial cavernous hemangioma confirmed by pathology and the related literature was reviewed.Results The lesion was located in frontal bone in eight cases,in parietal bone in one case and in occipital bone in one case.The lesions were round-shape hypodensity with clear margin in X-ray.The lesions were hyperdensity or slightly hyperdensity on CT scan,and were osteolytic lesions with a characteristic honeycomb or starburst pattern on bone window.The MRI features were complicated and variable.The lesions were heterogenous and unevenly enhanced signal intensity.Nine patients underwent radical resections and reconstructed immediately by titanium mesh.The patient with tumor in occipital bone underwent radical resection only.Macroscopically,the pathologic bone was a huge purple-red blush mass protruding from the skull surface.Histological examination revealed the diploe with large,thin-walled,dilated blood-filled spaces lined by flattened endothelial cells without evidence of malignancy.No recurrence was noted in any case during a follow-up period from 3 to 24 months.All the patients survived well without recurrence.Conclusions The imaging features of calvarial cavernous hemangioma have a high value in the diagnosis and may provide guidance for the treatment.The radical resection and immediate reconstruction treatment for calvarial cavernous hemangioma is satisfied.