A case of isolated oculomotor nerve palsy due to cavernous dural arteriovenous malformation (AVM)

A 44-year-old man developed left-sided blepharoptosis and diplopia. Clinical examination showed left-sided blepharoptosis, a 2.5 mm dilated but reactive left pupil and an impaired left-eye adduction. There was no proptosis, bruit or conjunctival injection. Computed tomographic scan (CT) and magnetic resonance image (MRI) of the orbits, cavernous sinus region and brainstem were normal. Carotid angiography demonstrated a dural arteriovenous malformation of the left cavernous sinus supplied by the meningohypophyseal artery of the internal carotid artery and the middle meningeal artery of the extrenal carotid artery, with drainage into the inferior petrosal sinus. Magnetic resonance angiography (MRA; 3D-time of flight method) showed a slight vascular blush at the cavernous sinus region, but not enough to yield a diagnosis. The oculomotor nerve palsy resolved over the following 7 months.