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.