De novo cerebral arteriovenous malformations: is epileptic seizure a potential trigger?

'De Novo' Brain AVMs-Hypotheses for Development and a Systematic Review of Reported Cases

Background and Objectives: Brain arteriovenous malformations AVMs have been consistently regarded as congenital malformations of the cerebral vasculature. However, recent case reports describing "de novo AVMs" have sparked a growing debate on the nature of these lesions. Materials and Methods: We have performed a systematic review of the literature concerning de novo AVMs utilizing the PubMed and Google Academic databases. Termes used in the search were "AVM," "arteriovenous," "de novo," and "acquired," in all possible combinations. Results: 53 articles including a total of 58 patients harboring allegedly acquired AVMs were identified by researching the literature. Of these, 32 were male (55.17%), and 25 were female (43.10%). Mean age at de novo AVM diagnosis was 27.833 years (standard deviation (SD) of 21.215 years and a 95% confidence interval (CI) of 22.3 to 33.3). Most de novo AVMs were managed via microsurgical resection (20 out of 58, 34.48%), followed by radiosurgery and conservative treatment for 11 patients (18.97%) each, endovascular embolization combined with resection for five patients (8.62%), and embolization alone for three (5.17%), the remaining eight cases (13.79%) having an unspecified therapy. Conclusions: Increasing evidence suggests that some of the AVMs discovered develop some time after birth. We are still a long way from finally elucidating their true nature, though there is reason to believe that they can also appear after birth. Thus, we reason that the de novo AVMs are the result of a 'second hit' of a variable type, such as a previous intracranial hemorrhage or vascular pathology. The congenital or acquired characteristic of AVMs may have a tremendous impact on prognosis, risk of hemorrhage, and short and long-term management.

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

Cerebral arteriovenous malformations (AVMs) are generally attributed to congenital lesions that arise from aberrant vasculogenesis between the fourth and eighth weeks of embryonic life. However, this dogma has been challenged by several recent observations, one of which is de novo formation of AVMs. Forty cases of de novo AVMs were published between 2000 and 2019, all of which involved a history of intracranial insult, such as vascular abnormalities or nonvascular conditions, prior to AVM diagnosis. We hereby present two unique operative cases of ruptured de novo AVMs in older adult patients. Case 1 is novel in the sense that the patient did not experience any kind of environmental trigger ("second hit") such as a previous intracranial insult, while Case 2 serves as the second report of a de novo AVM patient with a medical history of Bell's palsy. Although the exact mechanisms of AVM formation remain to be elucidated, it is likely to be a multifactorial process related to environmental and hemodynamic factors.

De novo thalamic arteriovenous malformation in a boy with a brainstem cavernous malformation

Brain arteriovenous malformations (bAVMs) have long been considered to be congenital, developing between the third and eighth weeks of embryogenesis. However, cases reporting their de novo formation suggest that these lesions can develop after birth and have challenged this concept. We present a case of a 6-year-old boy with a history of a brainstem cavernous malformation diagnosed after birth who later developed a de novo bAVM. The de novo occurrence of this bAVM distant to the site of the cavernous malformation and a prior negative catheter angiography contributes to the uncertainty of the dynamics and pathophysiology of bAVMs.

Arteriovenous Malformations: Congenital or Acquired Lesions?

OBJECTIVE

Arteriovenous malformations (AVMs) were believed to be congenital. However, an increasing number of de novo AVM cases have questioned this doctrine.

METHODS

A consensus meeting of international experts attempted to establish a consensus on the nature of these relatively rare but challenging vascular lesions. In addition, an extensive search of the subject was performed using the PubMed medical database.

RESULTS

All participants agreed that genetic factors may play a role in the pathogenesis of AVMs. All but 1 participant believed that an underlying genetic predisposition may be detected later on in a patient's life, whereas genetic variations may contribute to sporadic AVM formation. The presence of genetic variations alone may not be enough for an AVM formation. A second hit is probably required. This consensus opinion is also supported by our literature search.

CONCLUSIONS

We discuss the literature on the genetics of AVMs and compare it with the consensus meeting outcomes. The congenital or noncongenital character of intracranial AVMs has an impact on the understanding their biological behavior, as well as their efficient short-term and long-term management.

De novo brain arteriovenous malformation after tumor resection: case report and literature review

The congenital origin of brain arteriovenous malformations (bAVMs) has been increasingly challenged by reports of de novo bAVMs in patients previously confirmed to have no vascular malformation. We describe the oldest patient reported in the English language literature harboring a de novo bAVM. An uneventful frontal convexity meningioma resection was performed for a 60-year-old woman, and at 67 years of age, a bAVM was detected by MRI and confirmed by digital subtraction angiography at the site of the previous meningioma resection. This case adds to the growing literature that the etiology of bAVMs is most likely multifactorial.