Fusiform intracranial aneurysm

Fusiform intracranial aneurysms are a type of intracranial aneurysms with an elongated fusiform shape caused by atherosclerotic disease most common in the vertebrobasilar circulation.

Epidemiology

• 3%-13% of all intracranial aneurysms

Clinical presentation

They can be incidental or asymptomatic, discovered during work-up for unrelated symptoms. They can present as a nonspecific headache without hemorrhage or other neurological signs or symptoms, for example:

• transient ischemic attack or complete stroke
• mass effect with or without seizures
• subarachnoid or parenchymal hemorrhage

Pathology

Fusiform aneurysms are non-saccular dilatations involving the entire vessel wall for a short distance. They are termed cylindrical if it involves a somewhat longer length. The circumferential arterial dilatation results from pathological involvement of the entire artery.

Etiology

They are most commonly secondary to atherosclerotic disease but are also seen in mycotic aneurysms.

Location

• most commonly located in the vertebrobasilar circulation

Treatment and prognosis

Most small and some large focal dilatations, especially those that are asymptomatic, should be treated conservatively unless serial neuroimaging assessment indicates significant enlargement over time.