Cerebral Arteriovenous Malformations as Acquired Lesions: Case Reports and Review of the Literature

•Cerebral arteriovenous malformations are not always congenital for some reasons.•An increasing number of case reports of showing de novo cerebral arteriovenous malformations.•The first case without intracranial second-hit events prior to a de novo cerebral arteriovenous malformation diagnosis.•The de novo arteriovenous malformations might result from a brain insult caused by systemic diseases.