Choroid plexus arteriovenous malformations.

Among 24 arteriovenous malformations (AVMs) involving the choroid plexus, 11 were plexal type AVMs predominantly located in the choroid plexus of the lateral ventricle, and 13 were parenchymal type AVMs mainly situated in the paraventricular cerebral parenchyma. 83% of all AVMs involved both the choroid plexus and the paraventricular cerebral parenchyma. Most cases presented with intracranial hemorrhage, particularly intraventricular hemorrhage. The most serious surgical problem was a small residual nidus unrecognized at the initial operation causing postoperative hemorrhage. Five parenchymal type AVMs presented residual niduses in the choroid plexus, causing death in two cases. Two plexal type AVMs resulted in residual AVMs supplied by the cisternal segment of the anterior choroidal artery, situated in the medial temporal lobe. To prevent postoperative hemorrhage from a small residual nidus, immediate postoperative angiography while the patient is still under general anesthesia should be performed to identify any residual nidus.