Abstract
Case: The patient was a healthy 52-year-old woman. She visited a local doctor due to sudden ocular pain and exophthalmos in the right eye. Intracranial vascular lesions were not detected by contrast-enhanced computed tomography（CT）and computed tomography angiography（CTA）, and thyroid-associated ophthalmopathy was suspected due to the presence of external ocular muscle enlargement and elevated levels of anti-thyroglobulin antibodies. Exophthalmometry showed a proptosis of 22 mm on the right eye and 15 mm on the left eye; visual acuity was decreased and the intraocular pressure was high. Therefore, steroid pulse therapy and orbital decompression were performed, but the patient did not improve and was referred to our hospital. At the time of consultation, the patient’s visual acuity was 20 cm count fingers on the right eye and 0.04（1.2xS-5.50D=C-3.00D Ax 5°）on the left eye, and intraocular pressure was 27 and 17 mmHg on the right and left eye, respectively. Severe exophthalmos, upper conjunctiva, and upper scleral vascular distension were observed. We suspected a fistula of the internal carotid artery and cavernous sinus, and performed head magnetic resonance imaging（MRI）and magnetic resonance angiography（MRA）, which showed dilation of the superior ophthalmic vein and microvascular confluence near the anterior condylar confluence（ACC）. Afterwards, worsening of ocular pain and headache was observed. Angiography was thus performed at the department of neurosurgery to diagnose dural arteriovenous fistula（dAVF）near the ACC. The patient underwent transvenous embolization, and although the protrusion of the eye and the ocular movement disorder improved, severe visual dysfunction remained.
Conclusion: Among cases of dAVFs, the incidence of dAVFs occurring near the ACC is rare（3.6-4.2％）. However, when a sudden onset of unilateral ocular protrusion is observed, dAVFs near the ACC should be considered as a possible cause for further examination.
