In this article the authors report the case of a mixed cerebrovascular malformation in which a true arteriovenous malformation (AVM), harboring a nidus, is associated with a venous malformation that serves as the draining vein for the nidus. Despite the authors' preoperative rationale for exclusive extirpation of the AVM, an inadvertent injury and the obliteration of the venous malformation generated delayed postoperative neurological deterioration, which could clearly be attributed to venous hemorrhagic infarction. Because this is only the second instance of this type of mixed vascular malformation of the brain reported, which also underscores the concept of nonsurgical treatment of venous malformations, the authors discuss the diverse literature regarding mixed vascular malformations and the treatment of venous malformations.