Search

Spontaneous radiographic disappearance of cerebral aneurysms is often observed under special conditions such as giant aneurysms. However, spontaneous disappearance of an unruptured and nongiant intracranial saccular aneurysms is rare. We describe two cases of this rare vascular phenomenon. The first patient is a 64-year-old female diagnosed with a small unruptured aneurysm arising from the distal anterior cerebral artery. Spontaneous disappearance of the aneurysm on magnetic resonance angiography (MRA) was observed 5 years after the initial diagnosis. Continuous imaging surveillance also revealed spontaneous reappearance of the aneurysm 2 years later. The second patient is a 57-year-old female harboring a small unruptured saccular aneurysm arising from the M1–M2 bifurcation of the middle cerebral artery. The aneurysm showed spontaneous disappearance on MRA 13 years after the initial diagnosis. These cases provide a new insight into this natural dynamic process even in cases of a small unruptured intracranial saccular aneurysm.

Anterior cranial fossa (ACF) dural arteriovenous fistulas (DAVFs) are mainly fed by the ethmoidal arteries and sometimes have pial arterial feeders. DAVFs with pial arterial supply in ACF are extremely rare because most of the reported cases of DAVFs with pial arterial supply are located at the transverse sigmoid sinus and tentorium. A 68-year-old male presented with dizziness. Angiography showed cortical venous reflex (CVR) through an ACF DAVF fed by both bilateral ethmoidal arteries and by the right orbitofrontal artery as a pial feeder. The ethmoidal feeders were disconnected by craniotomy. The pial arterial feeder from the anterior cerebral artery was not found during surgery, and disconnection of the draining vein was not performed. CVR showed a significant reduction after the surgery. After 2 years of follow-up, angiography revealed an increased shunt flow from the pial feeder. Endovascular treatment using n-butyl-2-cyanoacrylate was performed, resulting in the complete occlusion of the fistula. DAVFs with pial supply are reported to carry a high risk of perioperative complications because of the restriction of the venous outflow and retrograde thrombosis of the pial artery. Endovascular pial feeder occlusion after surgical dural arterial feeder disconnection might achieve a safe and effective outcome. With close follow-up, the recurrence of increased shunt flow may be an appropriate timing for additional treatment. This rare condition may offer a new insight into the mechanisms of pial feeder development.