Cryptic arteriovenous malformation of the choroid plexus of the third ventricle.

A patient with a history of subarachnoid hemorrhage is reported. CT scan evidenced a high-density, round lesion in the anterior part of the third ventricle. A full angiographic study demonstrated no vascular malformation. After removal of a circumscribed hematoma in the anterior part of the third ventricle, an arteriovenous malformation of the choroid plexus was excised.