Ectopic recurrence following treatment of arteriovenous malformations in an adult: A case report and review of literature.

Background: Digital subtraction angiography (DSA), the gold standard for the diagnosis of intracranial arteriovenous malformations (AVMs), can show clean nidus resection, leading to a perceived cure. Most cases of intracranial AVM recurrence have been reported in pediatric patients. The conventional understanding indicates that AVMs arise when abnormal blood vessels develop between the fourth and eighth weeks of embryonic development, which coincides with the typical period of blood vessel formation in the brain. As such, recurrent ectopic AVM are rare in adults.

Case summary: Herein, we present the case of a 31-year-old adult with a history of an intracranial AVM originally diagnosed with a symptomatic de novo cerebellar AVM formation. Recurrence was observed five years following angiographically-confirmed excision of the initial AVM. DSA performed prior to initial AVM resection indicated no cerebellar abnormalities. Moreover, the recurrent arteries exhibited differences in arteries and draining veins. In addition to reporting this case, we analyzed six previously-reported adult patients with similar ectopic recurrent AVMs. These cases are summarized to review and explore the potential causes of ectopic AVM recurrence in adults, which increase the likelihood of acquired AVM.

Conclusion: The clinical course of the reported patients demonstrated the possibility of ectopic AVM recurrence in adults. The median time between the diagnosis of the initial AVM and the occurrence of ectopic recurrent AVM in adults was 11 years (range: 5-20 years). Magnetic resonance imaging follow-up for more than 10 years may be required in adult AVM-treated patients.