Intradural pseudoaneurysm is a broad term to describe several subtypes of

aneurysm An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus ( ...

s that fundamentally are different from the more typical intracranial berry-type aneurysms.

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Further reading