[A case of bilateral ophthalmoplegia caused by focal idiopathic hypertrophic pachymeningitis on the anterior cranial fossa].

A previously healthy 63-year-old man presented with a 2-weeks history of diplopia without headache. Neurological examination revealed total external ophthalmoplegia of the left eye and limitation of abduction of the right eye. Initial cranial MRI showed thickening and enhancement of the dura mater only on the anterior cranial fossa but unremarkable on the cavernous sinus. Idiopathic hypertrophic cranial pachymeningitis was diagnosed in the absence of demonstrable underlying infective, neoplastic, or systemic autoimmune disease by his clinical findings, laboratory tests and radiological examinations. Corticosteroid therapy was initiated with methylprednisolone (1,000 mg/day for 3 days), followed by oral prednisolone and tapering off. Eye movements improved with treatment and completely recovered within 4 weeks after starting administration, and cranial MRI at the 15 days after starting treatment showed improvement. We suggest that his ophthalmoplegia was caused by the inflammation of dura on the cavernous sinus beyond the thickening lesion of cranial MRI. In a case of bilateral ophthalmoplegia with or without headache, it is required to examine the dural thickening and enhancement on the anterior cranial fossa by cranial MRI.