An angiographic lesion mimicking pseudo-aneurysm in cerebral arteriovenousmalformation

In cerebral arteriovenous malformations (AVMs), a pseudoaneurysm represents rupture site, and its presence is known as a factor for rebleeding. We rep ort a case of cerebral AVM presenting with intracerebral haemorrhage in whi ch cerebral angiography showed a lesion mimicking pseudo-aneurysm. Although the patient needed urgent surgical decompression. it was delayed because e arly haematoma evacuation would induce rebleeding from the rupture site. Th e authors attempted to occlude the pseudoaneurysm interventionally before s urgery. After surgical excision, the lesion that was believed to be a pseud o-aneurysm was revealed as a partially thrombosed venous sac having a thick fibrous wall. In this report, the authors discuss the pitfalls in the inte rpretation of pseudo-aneurysms in angiographic AVM architecture.