Intraosseous meningioma: a rare cause of chronic optic neuropathy and exophthalmos

Background: The association of optic neuropathy, proptosis and chorioretinal folds is highly suggestive of an orbitopathy. Usual etiologies include an inflammatory orbitopathy, optic nerve sheath meningioma, sphenoid wing meningioma, exterioration of a sinus disorder, or an orbital tumor be it primary or secondary. History and signs: A 40-year-old man treated for systemic hypertension complained of decreased vision and floaters in his right eye. Initial examination revealed decreased visual acuity to 20/50 of the right eye with a slight dyschromatopsia, but a lack of afferent pupillary defect and normal visual fields. Fundus examination showed the presence of a slightly swollen right optic disc and chorioretinal folds. A diagnosis of presumed anterior ischemic optic neuropathy was made. Symptoms persisted and, five months later, right proptosis was noted. Magnetic resonance imaging revealed a diffuse thickening of the parieto-temporal bone and the greater wing of the sphenoid bone on the right side. Radiological differential diagnosis included fibrous dysplasia and metastasis. Therapy and outcome: Bone biopsy revealed a grade I intraosseous meningioma. Conservative management was chosen because the lesion was too extensive to be resected and radiotherapy is usually not efficient on grade I meningiomas. Conclusions: Intraosseous meningiomas are benign tumors which are due to meningeal cells entrapment during vaginal delivery. It is a rare tumor of slow progression. Therapy usually consists of resection and cranioplasty and/or radiotherapy. In the present case, decompression of the optic canal remains feasible in case of further visual loss.