Meningiomas are the most common benign intracranial neoplasm commonly arising from arachnoid cap cells located in the external layer of the arachnoid membrane. Almost 1% to 2% of meningiomas are lesions described as extradural meningiomas without association with the surface of the arachnoid membrane. Primary intraosseous meningiomas are rare (1, 2). Frontoparietal and orbital regions are the most common sites for intraossseous meningiomas (2). Here, we report a case of primary intraosseous

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... ngioma arising in the orbit. CASE REPORT A 46-year-old woman presented with left exophthalmos. She first noticed it approximately two years ago. She had experi-enced occasional blurred vision without diplopia or pain. Neurological examination was normal. She had no history of antecedent trauma. Laboratory studies were unremarkable. Orbital magnetic resonance imaging (MRI) revealed an expansible bony lesion arising from the orbital lateral wall of the left sphenoid bone accompanied by dural lesion. This bony lesion showed hypointensity on T1-and T2-weighted images with slightly heterogeneous enhancement after administration of gadolinium. However, the dural lesion was iso-and hyperintense on T1-and T2-weighted images with intense homogeneous enhancement after administration of gadolinium. The adjacent brain parenchyme in the left temporal lobe showed no abnormality (Fig. 1) . Precontrast facial computed tomography (CT) images showed abnormal bony expansion with increased sclerosis of the medullary space without visible thickened cortex in the orbital lateral wall of the left sphenoid bone. In addition, there were multi-