Case report of a de novo brainstem arteriovenous malformation in an 18-year-old male and review of the literature

Associations of Reported Genetic Risk Loci with Sporadic Brain Arteriovenous Malformations: Meta-analysis

An arteriovenous malformation (AVM) is an abnormal nidus of blood vessels that is characterized by a direct connection between arteries and veins without intervening in the capillary network. The exact underlying cause of sporadic AVMs is unknown, but many studies have reported genetic associations between genes that contribute to angiogenesis, vasculogenesis, and inflammation. Eleven studies retrieved from Medline Complete, PubMed, and Google Scholar up to February 2022 were included. Heterogeneity was assessed using I² and Q-tests. Publication bias was also assessed for the shortlisted CDKN2B-AS1 rs1333040 (T > C), ACVRL1 rs2071219 (A > G), and rs11169953 (C > T) polymorphisms. The rs1333040 polymorphism showed a lower association with sporadic brain AVM for T versus C in an allelic model (OR = 0.59, 95% confidence interval [CI] = 0.41-0.84). In the recessive model, rs2071219 for AA + AG vs. GG was OR = 0.62, 95% CI = 0.43-0.9. In the recessive model, rs11169953 CC + CT vs. TT was OR = 0.56, 95% CI = 0.33-0.95. In summary, the results of this study support the association between CDKN2B-AS1 and ACVRL1 polymorphisms and sporadic brain arteriovenous malformations. This study summarized the existing information and showed the need for more replication studies on the genetic basis of sporadic AVM. In the future, more genome-wide studies should be conducted to validate and fill existing gaps in knowledge about the mechanisms of sporadic AVM development.

De novo brain AVM following radiotherapy for cerebral cavernous malformation in a child: A 15-year clinical course

Multiple de novo brain arteriovenous malformations (bAVM) have been reported in the literature, raising questions about the contended purely congenital nature of these lesions. We present the 15-year course of a pediatric patient, who initially presented at age 5 with a thalamic cavernous malformation and was treated with radiosurgery, and then subsequently developed a thalamic de novo bAVM immediately adjacent to the initial lesion location, discovered 2 years later. Treatment of the bAVM entailed two transarterial embolizations and one radiosurgery session which ultimately led to complete angiographic resolution. Finally, this patient's course was complicated by intraparenchymal hemorrhage and acute obstructive hydrocephalus, and further imaging revealed two newly formed cavernous malformations, also associated with the initial lesion's location, that have remained stable since their formation. This case likely represents the second-hit model for the formation of vascular malformations, as sparsely supported by the current literature. According to this, genetically aberrant, yet quiescent, brain areas might promote the de novo formation of vascular malformations after brain injury, including radiation.

'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.

Spontaneous appearance of de novo intracranial arteriovenous malformation in hepatic cirrhosis

BACKGROUND

Intracranial arteriovenous malformations (AVMs) are rare lesions that can be congenital or acquired in early childhood, with fatal outcome in approximately 30% of cases. De novo formation during adulthood without established predisposing vascular pathology or previous brain insult is even less frequent.

CASE DESCRIPTION

We present a case of de novo brain AVM in an alcoholic Child-B cirrhosis setting. Thirty previously reported cases presented de novo AVM in patients of all ages that had another previous brain pathology or insult, such as AVM resection. Seventeen of those cases occurred in adult patients, with only 2 showing no significant predisposing factor. The present pathophysiological review covers and completes Mullan's hemodynamic "two-hit" model, associating probable thrombotic predisposition to AVM with brain insult triggering a later stage based on angiogenic stimuli.

CONCLUSIONS

This case report and literature review renews previously discussed hemodynamic theories and contributes to a fuller understanding of the pathogenesis and progression of AVM. We postulate a causal link between hepatopathy and de novo AVM, which should be strengthened and interpreted based on recent genetic data and future prospective studies.

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.

Review of de novo cerebral arteriovenous malformation: haemorrhage risk, treatment approaches and outcomes

Objective A small number of patients has been reported to develop a completely new or de novo arteriovenous malformation (AVM) after brain surgery, haemorrhage, head trauma or ischaemic stroke. The natural history of these lesions is unknown. In this review, both ruptured and unruptured de novo AVMs and their treatments were reviewed. Methods Published literature in the PubMed database citing 'de novo cerebral arteriovenous malformation' was reviewed. Additional studies were identified through reference searches in each reviewed article. A review was performed using all published cases, the treatment approaches and outcomes. Results A total of 38 patients, including 37 de novo AVMs reported from 1988 to 17 November 2017 and our one patient, was collected. The age at AVM diagnosis was 5-73 years (mean ± SD, 27.6 ± 20.5 years). The duration time, from negative examination to AVM diagnosis, was 2 months to 25 years (mean ± SD, 6.6 ± 4.9 years). The presentation of de novo AVM was headaches in three (7.9%) patients, bleedings in 12 (31.6%), incidental in 14 (36.8%) and seizure in nine (23.7%). The estimated risk of haemorrhage was 4.8% per year. Seventeen (44.7%) patients were treated with surgical resection, 10 (26.3%) were conservatively observed, nine (23.7%) were treated with radiosurgery and two (5.3%) were endovascularly embolised. The morbidity and mortality were reported as 5.3% and 7.9%, respectively. Conclusion Post-natal de novo AVMs have been reported. Their annual haemorrhage risk is 4.8%. Most of them are treated by surgical resection and are associated with morbidity and mortality.

De Novo Arteriovenous Malformation after Aneurysm Clipping

We report a 73-year-old woman with de novo arteriovenous malformations (AVMs) that developed in the ipsilateral parietal lobe after craniotomy and aneurysm clipping. While intracerebral AVMs are considered to be congenital lesions, there have been several reported cases of acquired AVM arising after ischemic or traumatic episodes. We summarize previously reported cases of such acquired 'de novo' AVMs with a discussion of some pathophysiological responses or factors suggested to promote their development.

Arteriovenous Malformation in a Youth with Atypical Autism Symptoms

Cerebral arteriovenous malformations (AVMs) present a challenge to diagnose in children with developmental disability, because of the overlap in behavioral symptoms and neurologic manifestations. They have been very rarely reported in conjunction with autism spectrum disorder. This case involves a 13 year old male with a history of autism spectrum disorder and significant behavioral issues diagnosed with a thalamic AVM following lateralizing neurologic symptoms. Despite radiosurgical treatment, hemorrhage followed consequently causing extensive neurologic injury and death. This case emphasizes the need for close follow up and coordination within a medical home for children with developmental disabilities. A multidisciplinary team approach is ideal to allow detection of subtle neurologic changes over time that may be masked as behavioral difficulties.

De novo AVM formation following venous sinus thrombosis and prior AVM resection in adults: report of 2 cases

Brain arteriovenous malformations (AVMs) are traditionally considered congenital lesions, arising from aberrant vascular development during the intrauterine period. Rarely, however, AVMs develop in the postnatal period. Individual case reports of de novo AVM formation in both pediatric and adult patients have challenged the traditional dogma of a congenital origin. Instead, for these cases, a dynamic picture is emerging of AVM growth and development, initially triggered by ischemic and/or traumatic events, coupled with genetic predispositions. A number of pathophysiological descriptions involving aberrant angiogenic responses following trauma, hemorrhage, or inflammation have been proposed, although the exact etiology of these lesions remains to be elucidated. Here, the authors present 2 cases of de novo AVM formation in adult patients. The first case involves the development of an AVM following a venous sinus thrombosis and to the authors' knowledge is the first of its kind to be reported in the literature. They also present a case in which an elderly patient with a previously ruptured AVM developed a second AVM in the contralateral hemisphere 11 years later. In addition to presenting these cases, the authors propose a possible mechanism for de novo AVM development in adult patients following ischemic injury.

The natural history of cerebral arteriovenous malformations

Cerebral arteriovenous malformations (AVMs) are composed of a complex tangle of abnormal arteries and veins and are a significant source of cerebral hemorrhage and consequent morbidity and mortality in young adults, representing a diagnostic and therapeutic challenge. Current natural-history studies of cerebral AVMs report overall annual rates of 1% and 3% for the risk of epilepsy and hemorrhage, respectively. Unruptured AVMs have an annual hemorrhage rate of 2.2% while ruptured lesions have an annual hemorrhage rate of 4.5%. These hemorrhage rates are can change over time, particularly for hemorrhagic lesions, with the rebleed rate ranging from 6% to 15.8% in the first year after rupture across several studies. Besides hemorrhage, other significant risk factors for AVM hemorrhage include deep location, deep venous drainage, associated aneurysms, and pregnancy. Other factors include patient age, sex, and small AVM size, which are not currently considered significant risk factors for AVM hemorrhage. In addition to hemorrhage risk and seizure risk, the natural history of an AVM also encompasses the daily psychologic burden that a patient must endure knowing that he or she possesses an untreated AVM. This chapter reviews the epidemiology, clinical features, and natural history of cerebral AVMs.

Lower Risk of Intracranial Arteriovenous Malformation Hemorrhage in Patients With Hereditary Hemorrhagic Telangiectasia

BACKGROUND

Patients diagnosed with hereditary hemorrhagic telangiectasia (HHT) are at risk of developing intracranial arteriovenous malformations (AVM). However, the clinical manifestations and natural history of HHT-related AVMs remain unclear due to the rarity of these lesions.

OBJECTIVE

To clarify the clinical characteristics and hemorrhagic risk in HHT-related AVMs.

METHODS

We performed a retrospective review of all patients diagnosed with both HHT and intracranial AVMs who were evaluated at our institution from 1990 to 2013. Patients with missing data or lost to follow-up were excluded. Baseline characteristics and subsequent hemorrhagic risk were evaluated.

RESULTS

In an AVM database of 531 patients with 542 AVMs, a total of 12 HHT patients (2.3%) with 23 AVMs were found. Mean age at diagnosis was 36.5 years, with 41.7% male. Compared to patients with sporadic AVMs, patients with HHT were less likely to present with ruptured AVM (P = .04), headaches (P = .02), and seizures (P = .02), and presented with better modified Rankin scores (P < .01). HHT-related AVMs were smaller in size (P < .01), of lower Spetzler-Martin grade (P = .01), and had less temporal lobe involvement (P = .02) compared to sporadic AVMs. Six HHT patients (50.0%) were found with multiple intracranial AVMs. One hemorrhage was found during an observation period of 149.6 patient-years and 297.5 lesion-years, translating to 1.3% per patient per year or 0.7% per AVM per year.

CONCLUSION

HHT-related AVMs are smaller in size with lower Spetzler-Martin grade and less temporal lobe involvement than sporadic AVMs. Patients with HHT frequently present with multiple intracranial AVMs. Conservative management is generally recommended due to lesion multiplicity and relatively low hemorrhagic risk.

Development of De Novo Arteriovenous Malformation Following Ischemic Stroke: Case Report and Review of Current Literature

BACKGROUND

Arteriovenous malformations (AVMs) are hypothesized to be static, congenital lesions developing as early as 4 weeks of fetal life. New literature has shown that AVMs may represent dynamic and reactive vascular lesions arising from cerebral infarction, inflammation, or trauma. A literature search reveals 17 previously reported cases of new AVM formation after previous negative imaging studies. This reactive development or "second hit" theory suggests that at a molecular level, growth factors may play a vital role in aberrant angiogenesis and maturation of an arteriovenous fistula into an AVM.

CASE DESCRIPTION

A 52-year-old female presented with a ruptured left frontal AVM demonstrated by computed tomography angiography and digital subtraction angiography. The patient had suffered an acute ischemic stroke in the similar cerebral vascular territory 8 years prior due to left internal carotid artery occlusion. Detailed neuroimaging at that time failed to reveal any vascular malformation, suggesting that the AVM might have developed in response to initial vascular insult.

CONCLUSIONS

We believe that there might exist a subset of AVMs that display dynamic characteristics and could potentially appear, grow, or resolve spontaneously without intervention, especially in the presence of local growth factors and molecular signaling cascades. When combined with a previous cerebral insult such as stroke, trauma, or inflammation, de novo AVM formation may represent a "second hit" with abnormal angiogenesis and vessel formation.

Long-term hemorrhagic risk in pediatric patients with arteriovenous malformations

OBJECTIVE Compared with the general population, the specific natural history of arteriovenous malformations (AVMs) in pediatric patients is less well understood. Furthermore, few pediatric studies have compared posttreatment hemorrhagic risk and functional outcome across different treatment modalities. The objective of this study was to elucidate these points. METHODS The authors retrospectively reviewed all pediatric patients with AVMs evaluated at their institution between 1990 and 2013. The AVM natural history was represented by hemorrhagic risk during the observation period. For treated patients, the observation period was defined as the interval between diagnosis and treatment. Posttreatment hemorrhagic risk and functional outcomes were also assessed. RESULTS A total of 124 pediatric patients with AVMs were evaluated, and 90 patients (72.6%) were retained through follow-up. The average patient age was 13.3 ± 3.8 years, with a mean follow-up period of 9.95 years. The overall AVM obliteration rate was 59.7%. Radiosurgery had an obliteration rate of 49.0%. Thirteen patients were managed conservatively. Four patients under observation hemorrhaged during a total interval of 429.4 patient-years, translating to an annual risk of 0.9%. Posttreatment hemorrhagic risk by treatment modalities were categorized as follows: surgery ± embolization (0.0%), radiosurgery ± embolization (0.8%), embolization alone (2.8%), surgery + radiosurgery ± embolization (3.5%), and observation (0.8%). A significantly higher risk of posttreatment hemorrhage was observed for patients with hemorrhagic presentation (p = 0.043) in multivariate analysis. Seizure presentation, frontal lobe location, nonheadache presentation, and treatment modality were significantly associated with increased risk of poor functional outcomes. CONCLUSIONS In this study of pediatric patients with AVMs, the natural history of hemorrhage was relatively low at 0.9%. Resection remained the optimal management for hemorrhage control and functional outcome perseverance in these pediatric patients with AVMs. AVM obliteration is a valid treatment goal, especially for patients with ruptured presentation, to prevent further hemorrhages later in life.

Total temporary occlusion of blood flow for several hours to treat a giant deep arteriovenous malformation: A series of multiple operations to save a young life

Background:

The treatment of giant deep arteriovenous malformations (AVMs) remains challenging.

Case Description:

We report a case of giant deep AVM diagnosed in a 9-year-old girl, for whom the AVM rupture occurred 9 years later. At the age of 9, the girl developed mild left hemiparesis. Magnetic resonance imaging revealed a giant deep AVM. The patient underwent one course of stereotactic radiotherapy followed by serial imaging. At the age of 18, we admitted her to our department with left hemiparesis and a loss of consciousness. Computed tomography showed intracerebral hemorrhage related to AVM. The treatment process proved challenging, with recurrent intracerebral hemorrhages. During the second operation, we used total temporary occlusion for almost 4 hours. Eventually, after 4 rounds of embolizations, 4 microsurgical operations, and a month-and-a-half after admission, AVM was successfully occluded. Five years after this treatment, the patient regained the ability to walk without assistance, although a moderate disability with visual changes remained (Modified Rankin Scale score 3).

Conclusion:

This case illustrates that the cumulative risk of rupture of a high-grade AVM in young patients is evident, while treatment may prove successful with satisfactory results.

De novo arteriovenous malformation in a patient with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant systemic disorder characterized by the enlargement of capillaries, recurrent nosebleeds, and multiple arteriovenous malformations (AVMs). Although cerebral AVMs are traditionally considered to be congenital lesions, some reports have described de novo AVMs, which suggests that the authors believed them to be dynamic conditions. In this article, the authors describe the case of a 5-year-old boy with HHT in whom a de novo cerebral AVM was detected after a negative MRI result at 5 months. To the authors' knowledge, this is the first report of a de novo AVM in a patient with HHT. In patients with a family history of HHT, de novo AVMs are possible, even when no lesions are detected at the first screening. Therefore, regular screenings need to be performed, and the family should be informed that AVMs could still develop despite normal MRI results.

Management of unbled brain arteriovenous malformation study

In a recent trial limited to arteriovenous malformations discovered not to have bled, medical management was superior to medical management plus intervention. The trial was halted after 226 randomizations and a mean follow-up of 3.3 years owing to a disparity favoring the medical arm. Eligible patients were selected as suitable for lesion eradication. The initial sample size of 800 and follow-up plans for a mean of 7 years were lowered and shortened, respectively, by the outcome data. An application for extended follow-up was given poor priority scores owing to estimations that the disparities in outcomes would not change significantly.

Pediatric de novo cerebral AVM: report of two cases and review of literature

PURPOSE

Cerebral arteriovenous malformation (AVM) is traditionally thought of as a congenital diagnosis. In recent years, there has been infrequent reports of this neurovascular condition presenting as de novo entities.

METHODS

The authors report two cases of pediatric patients who present with de novo cerebral AVMs. In both cases, the patients had magnetic resonance imaging (MRI) of the brain done as part of the work-up for first-onset seizures. At that point in time, the scans were unremarkable. After a latent period of approximately 6 and 9 years respectively, a repeated MRI brain scan showed evidence of de novo AVM for each patient.

RESULTS

Both patients did not have radiological evidence of cerebral AVM during their first presentation of seizures. However, a repeated MRI brain scan after a period of 6 and 9 years demonstrated new findings of cerebral AVM for each patient.

CONCLUSIONS

Currently, the disease of cerebral de novo AVM remain as an ambiguous condition that is poorly understood. With the advances in molecular diagnostics, there are possibilities of exploring biochemical profiles for better understanding of the origin of cerebral AVMs. However, in the meantime, owing to the unpredictable nature of cerebral AVMs, clinicians should have increased awareness of this unique condition. This is especially important, as definitive treatment is available to prevent devastating neurological sequelae from cerebral AVM rupture.