Biopsy-negative cranial arteritis with complete oculomotor nerve palsy.

: Cranial arteritis (CA) presenting as sudden blindness is well documented, and early recognition of this entity in an elderly patient with visual loss or diplopia is of critical importance. This entity presents a difficult diagnostic problem when temporal artery biopsy is negative, as in our case, or when the erythrocyte sedimentation rate is normal. The present report details an unusual patient with "occult temporal arteritis" who sustained abrupt monocular visual loss and subsequent ipsilateral ophthalmoplegia involving all functions of the oculomotor nerve. Despite negative biopsies of each temporal artery, other probable etiologies of the symptom complex were excluded, and the diagnosis of cranial arteritis is warranted. The patient is unique in that the oculomotor palsy is complete and permanent. This report emphasizes cranial arteritis masquerading as an intracranial aneurysm.