A case of pericapillary arteriovenous malformation

Abstract

Background: Pericapillary arteriovenous malformation (pAVM) frequently causes intracerebral hemorrhage (ICH). However, definitive diagnosis of pAVM is difficult, as it manifests angiographically as cerebral venous malformations. Case description: A 57-year-old woman presented with sudden headache. Computed tomography revealed left parietal subcortical hemorrhage. Angiography demonstrated abnormal veins at the hematoma. Under suspicion of pAVM, resection was performed 3 months after the onset of symptoms. Color Doppler identified one vein with both red and blue colored flows running into the subcortex. This vein was followed, and a cluster of abnormal vessels was identified and resected. Histological investigation demonstrated that one of the arterioles connected directly to a dilated thin-walled venule, leading to a diagnosis of pAVM. Conclusions: ICH is rarely caused by venous malformation, but is frequently triggered by pAVM. Therefore, pAVM should be suspected when angiography shows abnormal vessels resembling venous malformation in patients with ICH. pAVM is only definitively diagnosed by histology. Angiographically identified abnormal vessels are draining veins, and a core pAVM is not seen radiologically. Surgery comprises the following steps: 1) following the abnormal vein along the sulcus; 2) aspiration of a small amount of cortex tissue to enable the vein to be followed; 3) identification of a cluster of abnormal arterioles in the subcortex; 4) en bloc removal of these abnormal vessels. Identification of the draining vein is the key point; color Doppler is useful for this, as a mixture of red and blue colors are displayed due to the presence of back and forth blood streams.

Keywords

• Pericapillary arteriovenous malformation
• Venous malformation
• Color Doppler
• Intracranial hemorrhage
• Dilated venule
• Draining vein