視神経管拡大を伴った視神経海綿状血管腫の1例  [in Japanese] Cavernous Malformation of the Optic Nerve with Enlargement of the Optic Canal : A Case Report  [in Japanese]

We describe a cavernous malformation of the optic nerve with enlargement of the optic canal. This 17-year-old high school girl presented with sudden onset of the temporal and orbital pain, and blurred vision on the right. She visited an eye clinic and was treated with eye drops and a steroid under the diagnosis of optic neuritis. Three months later, she again experienced the same symptoms and received MRI that revealed a lesion in the right optic nerve. She was referred to us for further evaluation and treatment. On admission, her neurological exam showed deterioration of visual acuity: rt. 0.02 (0.04) It. 0.06 (1.5), central scotoma of the right visual field by Goldmann perimetry and optic atrophy. A Rhese-Goalwins view of X-ray demonstrated an enlargement of the right optic canal. MRI revealed diffuse swelling of the intracranial portion of the right optic nerve without any enhanced lesion by gadolinium DTPA. Because of deterioration of the right vision and suspicion of a mass lesion, an exploratory craniotomy was performed. The right optic nerve was enlarged with yellowish and brownish discoloration in part, suggesting intra-axial vascular malformation associated with hemorrhage. We performed a neurotomy of the right optic nerve and the mass was removed en bloc. Histological examination of the specimen disclosed cavernous malformation. Only 22 cases of cavernous malformation originating from the optic nerve and chiasm have been reported as far as we have learned from the literature. We review these cases and discuss the clinical characteristics and treatment modality of the cavernous malformation of the optic nerve.