De novo cerebral arteriovenous malformation: case report and literature review

Molecular and genetic mechanisms in brain arteriovenous malformations: new insights and future perspectives

Brain arteriovenous malformations (bAVMs) are rare vascular lesions made of shunts between cerebral arteries and veins without the interposition of a capillary bed. The majority of bAVMs are asymptomatic, but some may be revealed by seizures and potentially life-threatening brain hemorrhage. The management of unruptured bAVMs remains a matter of debate. Significant progress in the understanding of their pathogenesis has been made during the last decade, particularly using genome sequencing and biomolecular analysis. Herein, we comprehensively review the recent molecular and genetic advances in the study of bAVMs that not only allow a better understanding of the genesis and growth of bAVMs, but also open new insights in medical treatment perspectives.

Critical Appraisal of Randomized Controlled Trials on Unruptured Brain Arteriovenous Malformations

OBJECTIVE

Brain arteriovenous malformations management remains controversial despite the numerous, available treatment options. Randomized controlled trials (RCTs) theoretically provide the strongest evidence for the assessment of any therapeutic intervention. However, poorly designed RCTs may be associated with biases, inaccuracies, and misleading conclusions. The purpose of our study is to assess reporting transparency and methodological quality of the existing RCTs.

METHODS

A search was performed in the PubMed, Scopus, Embase, clinicaltrials.gov, and Cochrane databases. The search was limited to English literature. We included all published RCTs reporting on the management of unruptured brain arteriovenous malformations. The eligible studies were evaluated by 5 blinded raters with the CONsolidated Standards of Reporting Trials 2010 statement and the risk-of-bias 2 tool. The inter-rater agreement was assessed with the Fleiss' Kappa.

RESULTS

A randomized trial of unruptured brain arteriovenous malformations (ARUBA) and treatment of brain arteriovenous malformations (TOBAS) trials were evaluated. ARUBA achieved high CONsolidated standards of reporting trials compliance, while TOBAS showed a moderate one. In ARUBA the introduction, discussion, and other information sections reached the highest compliance rate (80%-86%). The lowest rates were recorded in the results and the methods (62% and 73%, respectively). The inter-rater agreement was moderate to substantial (54.1% to 78.4%). All the examined studies demonstrated a high risk of bias, mainly related to ill-defined intended interventions, missing outcome data, and selection of the reported results.

CONCLUSIONS

Our study confirmed the high risk of bias mainly attributed to several protocol violations, deviations, minimal external validity and selection, attrition, and allocation biases of the ARUBA trial. Analysis of the TOBAS trial revealed a moderate overall reporting clarity and a high risk of bias.

'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.

Parietal Arteriovenous Malformation Mimicking Carotid-cavernous Fistula in Context of Sinus Thrombosis: Bidirectional or Unidirectional Relationship? Literature Review

Cortically located arteriovenous malformations (AVMs) constitute majority of brain AVMs. A common drainage is through respective cortical veins into superior sagittal or transverse sinuses. Through a case report and literature review, we discuss three issues: first, the anomalous drainage of a cortical AVM into an anterior orbital venous drainage system; second, the impact of this drainage on the clinical picture; and third, importantly, the bidirectional versus unidirectional relationship of AVM and old venous sinus thrombosis.

Ectopic Recurrence of Arteriovenous Malformation After Radiosurgery: Case Report and Insight Regarding Pathogenesis

BACKGROUND

While prior studies reporting de novo arteriovenous malformations after birth are not uncommon, reports of ectopic recurrence of arteriovenous malformation after radiotherapy are scarce.

CASE DESCRIPTION

An 8-year-old girl with a ruptured cerebellar arteriovenous malformation was treated with stereotactic radiosurgery. The nidus was completely obliterated 17 months after stereotactic radiosurgery; however, 20 years later she had a rupture of a recurrent nidus that occurred adjacent to the original nidus, accompanied by a radiation-induced cyst. Surgical resection was performed, and subsequent pathologic examination revealed 2 different compartments: a typical nidus and a postirradiated degenerated nidus with an encapsulated hematoma. Immunohistochemical stains showed increased expression of Ki-67 and decreased expression of endoglin in endothelial cells in the recurrent nidus.

CONCLUSIONS

Depletion in endoglin may lead to the formation of vessel malformations in the presence of angiogenic stimuli. This case serves as a strong reminder of the importance of long-term follow-up after stereotactic radiosurgery, especially for pediatric cases.

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.

Coexistence of Intracranial Germ Cell Tumor with Growing Arteriovenous Fistula

BACKGROUND

A 26-year-old man was admitted with complaints of progressive depressive mood and general fatigue. Magnetic resonance imaging revealed diffuse enhanced lesions in the neurohypophyseal, pineal, and paraventricular regions and ventricular wall.

CASE DESCRIPTION

Endoscopic biopsy confirmed the presence of germ cell tumor, and chemoradiation therapy (CRT) was then performed. Most of the tumors disappeared after CRT except for the right paraventricular lesion. Follow-up magnetic resonance imaging performed 14 months after CRT showed enlargement of this residual lesion. In addition to tumor growth, coexistent flow void signals within the tumor increased. Angiographically, this vascular lesion mimicked arteriovenous malformation, which was mainly fed by the lenticulostriate artery and drained into the internal cerebral vein. Transarterial embolization was performed, resulting in effective flow reduction. Subsequently, the tumor was resected without complications. It was histopathologically diagnosed as a mature teratoma with an arteriovenous fistula (AVF). Arterial components were observed to directly connect to venous components within the tumor without any intermediate nidal components.

CONCLUSIONS

To the best of our knowledge, this is the first reported case of an intracranial germ cell tumor coexistent with a growing AVF. AVF developed within a CRT-refractory teratomatous component, which was successfully treated with embolization followed by surgical resection.

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.

Progression in size of an arterio-venous malformation

We report a case of a young girl who was admitted with history of sudden onset left hemiplegia, when she was 5 years old. Investigations revealed no vascular malformation or abnormality. On conservative treatment, she progressively improved and had residual hemiparesis. She continued to have intermittent episodes of generalized and focal convulsions. For persistent convulsions, she was investigated again with MRI and angiography after 5 years of first presentation. Investigations at this time revealed a large arteriovenous malformation in the left posterior frontal region. The arteriovenous malformation was resected by surgery. Following surgery, the episodes of convulsions reduced. Arteriovenous malformations are generally considered to be congenital lesions and their size and physical architecture generally remains constant. The presented case clearly demonstrated de novo appearance or growth of the size of the arteriovenous malformation. Such a pattern of development and growth of a arteriovenous malformation is rare and only infrequently reported.

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.

De Novo Arteriovenous Malformation Growth Secondary to Implantation of Genetically Modified Allogeneic Mesenchymal Stem Cells in the Brain

BACKGROUND AND IMPORTANCE

Local biological drug delivery in the brain is an innovative field of medicine that developed rapidly in recent years. Our report illustrates a unique case of de novo development of a cerebral arteriovenous malformation (AVM) after implantation of genetically modified allogeneic mesenchymal stem cells in the brain.

CLINICAL PRESENTATION

A 50-year-old man was included in a prospective clinical study (study ID number CM GLP-1/01, 2007-004516-31) investigating a novel neuroprotective approach in stroke patients to prevent perihematomal neuronal damage. In this study, alginate microcapsules containing genetically modified allogeneic mesenchymal stem cells producing the neuroprotective glucagon-like peptide-1 (GLP-1) were implanted. Three years later, the patient presented with aphasia and a focal seizure due to a new left frontal intracerebral hemorrhage. Angiography revealed a de novo left frontal AVM.

CONCLUSION

The development of an AVM within a period of 3 years after implantation of the glucagon-like peptide-1-secreting mesenchymal stem cells suggests a possible relationship. This case exemplifies that further investigations are necessary to assess the safety of genetically modified cell lines for local biological drug delivery in the brain.

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.

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.

Renal Arteriovenous Shunts: Clinical Features, Imaging Appearance, and Transcatheter Embolization Based on Angioarchitecture

Renal arteriovenous (AV) shunt, a rare pathologic condition, is divided into two categories, traumatic and nontraumatic, and can cause massive hematuria, retroperitoneal hemorrhage, pain, and high-output heart failure. Although transcatheter embolization is a less-invasive and effective treatment option, it has a potential risk of complications, including renal infarction and pulmonary embolism, and a potential risk of recanalization. The successful embolization of renal AV shunt requires a complete occlusion of the shunted vessel while preventing the migration of embolic materials and preserving normal renal arterial branches, which depends on the selection of adequate techniques and embolic materials for individual cases, based on the etiology and imaging angioarchitecture of the renal AV shunts. A classification of AV malformations in the extremities and body trunk could precisely correspond with the angioarchitecture of the nontraumatic renal AV shunts. The selection of techniques and choice of adequate embolic materials such as coils, vascular plugs, and liquid materials are determined on the basis of cause (eg, traumatic vs nontraumatic), the classification, and some other aspects of the angioarchitecture of renal AV shunts, including the flow and size of the fistulas, multiplicity of the feeders, and endovascular accessibility to the target lesions. Computed tomographic angiography and selective digital subtraction angiography can provide precise information about the angioarchitecture of renal AV shunts before treatment. Color Doppler ultrasonography and time-resolved three-dimensional contrast-enhanced magnetic resonance angiography represent useful tools for screening and follow-up examinations of renal AV shunts after embolization. In this article, the classifications, imaging features, and an endovascular treatment strategy based on the angioarchitecture of renal AV shunts are described.

Therapeutic management of cerebral arteriovenous malformations: a review

The therapeutic management of cerebral arteriovenous malformations has undergone significant change over the past 40 years. Embolization, radiosurgery, advanced imaging modalities, neuropsychological testing and advances in surgical technique has both significantly improved our ability to treat patients, as well as confounding the landscape as to what constitutes best medical practice. Variability in natural history provides additional challenges in that it is challenging to determine an accurate estimate of the risk of hemorrhage, morbidity and mortality. It is clear that the complexity of the treatment of these lesions demands a multidisciplinary approach. The need for a team of neurosurgeons, interventional and diagnostic neuroradiologists, neurologists, radiation oncologists and neuropsychologists will improve outcomes and aid in determining best therapy for patients.

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.

Symptomatic de novo arteriovenous malformation in an adult: Case report and review of the literature

BACKGROUND

Cerebral arteriovenous malformations (AVMs) have been long thought to be a congenital anomaly of vasculogenesis in which arteries and veins form direct connections forming a vascular nidus without an intervening capillary bed or neural tissue. Scattered case reports have described that AVMs may form de novo suggesting they can become an acquired lesion.

CASE DESCRIPTION

The current case report describes a patient who presented with new-onset seizures with an initial negative magnetic resonance imaging (MRI) of the brain and subsequently developed an AVM on a MRI 9 years later.

CONCLUSION

This case joins a small, but growing body of literature that challenges the notion that all AVMs are congenital.

Development of a de novo arteriovenous malformation after severe traumatic brain injury

Arteriovenous malformations (AVMs) are typically considered congenital lesions, although there is growing evidence for de novo formation of these lesions as well. The authors present the case of an AVM in the same cerebral cortex that had been affected by a severe traumatic brain injury (TBI) more than 6 years earlier. To the best of the authors' knowledge, this is the first report attributing the formation of an AVM directly to TBI.

Are parenchymal AVMs congenital lesions?

A long-held dogma in neurosurgery is that parenchymal arteriovenous malformations (AVMs) are congenital. However, there is no strong evidence supporting this theory. An increasing number of documented cases of de novo formation of parenchymal AVMs cast doubt on their congenital nature and suggest that indeed the majority of these lesions may form after birth. Further evidence suggesting the postnatal development of parenchymal AVMs comes from the exceedingly rare diagnosis of these lesions in utero despite the widespread availability of high-resolution imaging modalities such as ultrasound and fetal MRI. The exact mechanism of AVM formation has yet to be elucidated, but most likely involves genetic susceptibility and environmental triggering factors. In this review, the authors report 2 cases of de novo AVM formation and analyze the evidence suggesting that they represent an acquired condition.

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

MATERIAL AND METHODS

The pathogenesis of cerebral arteriovenous malformations (cAVMs) is still not well understood. Generally, cAVMs are thought to be congenital lesions originating prenatally. We report a 7-year-old boy diagnosed with a de novo cAVM after 3 years of recurrent epileptic seizures.

RESULTS

MR imaging at 4 years of age was normal. Follow-up MR imaging 3 years later demonstrated a de novo 2-cm cAVM in the right occipital lobe, confirmed by conventional angiography. We reviewed five previously reported cases of de novo cAVMs who did not have a previous neurovascular abnormality. Including our case, recurrent epileptic seizures are the major presentation (83.3 %) before de novo cAVM occurrence.

CONCLUSION

We suggest that epileptic seizure is a potential trigger of de novo cAVMs.

Juvenile pilocytic astrocytoma in association with arteriovenous malformation

Pilocytic astrocytomas are highly vascular, relatively common primary brain tumors in the pediatric population, but their association with a true arteriovenous malformation (AVM) is extremely rare. We describe an eight-year-old girl with a right supratentorial juvenile pilocytic astrocytoma (WHO grade I) with an angiographically documented AVM entangled in the tumor mass who presented with intracranial hemorrhage due to a ruptured anterior choroidal artery pseudoaneurysm encased in the lesion. The AVM nidus as well as the hemorrhage site was embolized with Onyx. A literature review revealed only one previous report of a true intermixture of these two lesions. We hypothesize whether the association of vascular malformations and primary brain tumors are merely coincidental or if they point to the existence of a distinct entity and/or a common etiologic factor.

De novo cerebral arteriovenous malformation in a child with previous cavernous malformation and developmental venous anomaly

Although cerebral vascular malformations are traditionally considered to be congenital lesions, they often become clinically evident in the 3rd to 4th decades of life, leading to the assumption of a long silent clinical period. Unlike vein of Galen malformations, antenatal diagnosis of cerebral arteriovenous malformations (AVMs) is highly uncommon. Postnatal development of an AVM is an emergent concept supported by more clinical observations. Genetic and biological studies demonstrate that an environmental trigger ("second hit") in addition to genetic predisposition may be a key in understanding the pathophysiology of AVMs and other cerebral vascular lesions such as cavernous malformations (CMs). The authors describe a 6-year-old boy in whom a giant CM was diagnosed and a de novo AVM was detected 25 months after initial resection of the CM. This case seems to support the second-hit hypothesis.

Intracranial Aneurysms and Vascular Malformations: Diagnosis for Therapy

In the second part of our overviewstudy the diagnosis for the treatment of our patients with intracranial vascular malformations (aneurysms / AVMF– arteriovenous malformations) is again shown in a region of about 500.000 inhabitants and just an overview of the outcome. This second part will be an overall comparison between the former diagnostic for the treatment and the here described diagnostic for the treatment (CTA, MRA, DSA rot / microsurgery, endovascular interventional techniques etc.), concerning also the topography and the demography. The future trends are also outlined.

Cerebral arteriovenous malformations: issues of the interplay between stereotactic radiosurgery and endovascular surgical therapy

Intracranial arteriovenous malformations (AVMs) are congenital lesions frequently diagnosed as a result of hemorrhage or other neurological symptoms. Prevention of such devastating neurological injury has promoted a variety of treatment strategies. The rich history of multimodal therapy in the treatment of AVMs includes microsurgery, endovascular embolization, and stereotactic radiosurgery (SRS). This article reviews the biology and natural history of AVMs, as well as their treatment with both SRS and endovascular neurosurgery. It considers various paradigms and goals of endovascular treatment, along with relevant issues such as the features of an AVM to be targeted. Issues of the interplay between SRS and endovascular neurosurgery include the compartments of an embolized AVM to contain within the radiosurgery plan, the radioprotective and radiosensitizing effects of the embolic agent, the durability of embolization, and the sequencing of embolization with respect to the radiosurgical treatment. Published literature on these topics is sparse, and the flimsiness of the data offers limited guidance.

The effect of age on arteriovenous malformations in children and young adults undergoing magnetic resonance imaging

OBJECTIVE

Arteriovenous malformations (AVMs) are the most frequently encountered structural cause of spontaneous intracerebral hemorrhage in childhood, excluding hemorrhages of prematurity. The goal of our study was to examine the relationship between age and AVM prevalence on imaging in children, which to date has not been well described.

METHODS

We queried the electronic and radiographic records of 14,936 consecutive patients aged 25 years or less who had undergone brain magnetic resonance imaging (MRI) at a single institution over an 11-year period to identify those with a cerebral AVM. We collected age, gender, and other demographic characteristics for all patients. For all patients with a cerebral AVM, we recorded the location, size, drainage pattern, Spetzler-Martin grade, medical history, and presence of neurological symptoms.

RESULTS

Cerebral AVMs were identified in 55 patients (0.37%). The prevalence of AVMs detected on MRI significantly increased with age (p = 0.001). AVMs were found in 0.34% of boys (25 of 7,447) and 0.40% of girls (30 of 7,489). AVMs were most commonly identified in the frontal lobes (36%), followed by parietal (20%) and temporal lobes (13%). Sixty percent (n = 33) of AVMs were less than 3 cm in size, 35% (n = 19) were 3-6 cm in size, and 5.5% (n = 3) were greater than 6 cm in size. As for Spetzler-Martin grade of the AVMs, 25.5% were grade I, 18.2% were grade II, 36.4% were grade III, 16.4% were grade IV, and 3.6% were grade V.

CONCLUSIONS

AVMs are seen more frequently on MRI with advancing age in children and young adults.

A case of complex arteriovenous malformation with skull destruction presented in sixth decade of life

Intracranial AVMs are typically diagnosed before the patient has reached the age of 40 years, and a few cases have been reported of AVM with skull destruction. We described a rare case of a complex cerebral AVM with skull destruction, presented de novo in 52-year-old woman with epileptic seizures. Neuroimaging investigations revealed complex AVM in right hemisphere as well as extracranially, with signs of skull destructions, likely caused by significant involvement of feeders from external carotid artery. Neurosurgery treatment was not recommended due to morphological characteristics and drainage patterns of the AVM. EEG investigation showed discrete specific activity in correspondent area and pharmacology treatment for seizures was initiated. One year after the initial presentation patient had survived rebleeding episode witch left permanent neurology deficit. This patient considered as a rare case of complex AVM with skull destruction, presented de novo in sixth decade of life.

Risk factors and treatment outcomes of childhood stroke

Stroke is an important cause of childhood mortality and morbidity. The risk factors and pathophysiological processes of stroke in children are very different than those in adults. The range of risk factors is very wide, with over 100 presumptive risk factors described. There are a number of clinical guidelines, but despite recent increases in research, the evidence base underpinning these guidelines is sparse. Therefore, treatment is largely based upon expert consensus and extrapolation from adult data. Mortality from childhood stroke is relatively high and at least two-thirds of survivors have neurological impairments. Stroke can affect a wide range of neurocognitive domains and a high proportion of children require additional educational support and have a reduced quality of life.

The putative role of the venous system in the genesis of vascular malformations

Recent clinical and experimental evidence has challenged the traditional concept of the venous system as a “passive” element in the genesis and evolution of intracranial vascular malformations. The authors review the clinical and experimental evidence linking the venous system and its anomalies to the genesis of various intracranial vascular malformations, including dural arteriovenous fistulas, cavernous malformations, parenchymal arteriovenous malformations, and capillary telangiectasia. They also describe the potential significance of different associations of these vascular anomalies.

Neonatal giant pial arteriovenous malformation: genesis or rapid enlargement in the third trimester

A neonate with congestive heart failure at birth due to a nearly holohemispheric pial arteriovenous malformation is described. This occurred despite a normal second trimester prenatal sonogram. Successful treatment of heart failure was achieved by embolization alone. This case demonstrates that hemodynamically significant lesions may arise later or enlarge more rapidly in utero than previously thought.

De novo arteriovenous malformations: case report and review of the literature

Intracerebral arteriovenous malformations (AVMs) are traditionally recognized as congenital lesions. However, with the advent of frequent, noninvasive imaging of the brain, that notion has been challenged. We describe another patient with a de novo cerebral arteriovenous malformation and evaluate the reported literature for trends in the development of these lesions. Cases were selected from the English literature using the PUBMED database using the search term "acquired or de novo cerebrovascular arteriovenous malformations". A total of seven patients (including the one reported in this study) with de novo arteriovenous malformations are reported. Majority of patients were female, and mostly diagnosed as children. Their mean age at diagnosis was 18 years (6-32), and the mean time from the initial intracranial study to the diagnosis of an AVM was 8 years (3-17). De novo formation of AVMs is being increasingly reported, especially in young females. We present only the seventh such case reported in the literature and challenge the traditional view that all arteriovenous malformations are congenital in nature.

De novo cerebral arteriovenous malformation: Pink Floyd's song "Brick in the Wall" as a warning sign

BACKGROUND

Arteriovenous malformations are shunts between an artery and the venous system that lie within a nidus without an intervening capillary bed. These lesions are thought to be congenital, but recent reports have challenged this assumption.

CASE REPORT

A 50-year-old man presented to the emergency department with a generalized tonic-clonic seizure. Before the onset of his seizure, he experienced a vivid auditory hallucination of his favorite song by the band Pink Floyd, "A Brick in the Wall." He had been diagnosed with epilepsy 25 years previously. On presentation, his neurological examination was normal, but a computed tomography scan of the brain revealed a large arteriovenous malformation (AVM) occupying the left temporal lobe. Upon more detailed questioning, he recalled that a brain angiogram had been performed 25 years before and was reported to be normal. Neurosurgery was not performed in view of the size of the malformation. The patient is being followed-up as an outpatient.

CONCLUSION

AVMs may arise de novo and then spontaneously become symptomatic. Cerebral de novo AVM should be considered in the differential diagnosis in patients with complex auditory musical hallucinations or any new neuropsychiatric symptoms.

Pathogenesis and radiobiology of brain arteriovenous malformations: implications for risk stratification in natural history and posttreatment course

Brain arteriovenous malformations (BAVMs) are an important cause of intracerebral hemorrhage (ICH) in young adults. Biological predictors of future ICH risk are lacking, and controversy exists over previous studies of natural history risk among predominantly ruptured BAVM cohorts. Recent studies have suggested that the majority of BAVMs are now diagnosed as unruptured lesions, and that the risk according to natural history among these lesions may be less than previously assumed. In the first part of this review, the authors discuss available data on the natural history of BAVMs and highlight the need for future studies that aim to develop surrogate biomarkers of disease progression that accurately predict future risk of ICH in BAVMs. The etiology of BAVM remains unknown. Recent studies have suggested a role for genetic factors in the pathogenesis of sporadic BAVM, which is further supported by reports of familial occurrence of BAVM and association with known systemic genetic disorders (such as Osler-Weber-Rendu disease, Sturge-Weber disease, and Wyburn-Mason syndrome). Molecular characterization of BAVM tissue demonstrates a highly angiogenic milieu with evidence of increased endothelial cell turnover. Taken together with a number of reports of de novo BAVM formation, radiographic growth after initial BAVM diagnosis, and regrowth after successful treatment of BAVM, these findings challenge the long-held assumption that BAVMs are static lesions of congenital origin. In the second part of this review, the authors discuss available data on the origins of BAVM and offer insights into future investigations into genetics and endothelial progenitor cell involvement in the pathogenesis of BAVM. Current treatment options for BAVM focus on removal or obliteration of the lesion in an attempt to protect against future ICH risk, including microsurgical resection, endovascular embolization, and stereotactic radiosurgery (SRS). In the third part of this review, the authors discuss available data on SRS in BAVMs and highlight the need for future studies on the radiobiology of BAVMs, especially in regard to biomarker detection for tracking SRS response during the latency period. Insights from future investigations in BAVM may not only prove important for the development of novel therapies and relevant biomarkers for BAVM, but could also potentially benefit a variety of other disorders involving new vessel formation in the CNS, including stroke, tumors, moyamoya disease, and other cerebrovascular malformations.