Purpose: We report a patient with an occipital artery aneurysm below the scalp associated with a transverse-sigmoid sinus dural arteriovenous fistula (dAVF).
Case: An 84-year-old male noticed a painless pulsatile mass measuring 2 cm in the left occipital region. Computed tomography (CT) 6 years before did not confirm any subcutaneous mass. An inquiry was conducted, but there was no history of occipital trauma. Cerebral angiography revealed a left transverse-sigmoid sinus dAVF. The dilated left occipital artery was a major feeding blood vessel, and aneurysm formation was partially observed. There was no marked change in the aneurysmal shape 6 months after diagnosis.
Conclusion: Vascular wall stress related to an increase in blood flow and the fragility of the perivascular supporting tissue may have been involved in the pathogenesis.