Progression of multiple cryptic vascular malformations associated with anomalous venous drainage. Case report

Giant Intracranial Cavernous Malformations: A Review on Magnetic Resonance Imaging Characteristics

Background  Intracranial cavernous malformations (CMs), commonly known as cavernomas or cavernous angiomas, are low-flow, well-circumscribed vascular lesions composed of sinusoidal spaces lined by a single layer of endothelium and separated by a collagenous matrix without elastin, smooth muscle, or other vascular wall elements. A diameter greater than 3 cm for a CM is unlikely. These lesions may have atypical appearances on magnetic resonance imaging (MRI). MRI with advanced techniques such as a susceptibility-weighted image or T2-gradient echo, a diffusion-weighted image and corresponding apparent diffusion coefficient map, and diffusion tensor tractography have revolutionized the diagnostic approach to these lesions. Materials and Method  The present study reviews the etiopathogenesis, clinical manifestations, MRI strategy, and MRI appearances of the CMs, with a few examples of the giant CMs from our archive. Results  Intracranial giant CMs may have unexpected locations, sizes, numbers, and varied imaging appearances due to repeated hemorrhages, unusual enhancement patterns, intense perifocal edema, and unusual associations, making the differential diagnosis difficult. Conclusion  Familiarity with the MRI appearances of the giant intracranial CMs and the differential diagnosis improves diagnostic accuracy and patient management.

Cerebral cavernous malformations do not fall in the spectrum of PIK3CA-related overgrowth

Somatic gain-of-function (GOF) mutations in phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), the catalytic subunit of phosphoinositide 3-kinase (PI3K), have been recently discovered in cerebral cavernous malformations (CCMs), raising the possibility that the activation of PI3K pathways is a possible universal regulator of vascular morphogenesis. However, there have been contradicting data presented among various groups and studies. To enhance the current understanding of vascular anomalies, it is essential to explore this possible relationship between altered PI3K signalling pathways and its influence on the pathogenesis of CCMs. GOF PIK3CA-mutants have been linked to overgrowth syndromes, allowing this group of disorders, resulting from somatic activating mutations in PIK3CA, to be collectively named as PIK3CA-related overgrowth spectrum disorders. This paper reviews and attempts to conceptualise the relationships and differences among clinical presentations, genotypic and phenotypic correlations and possible coexistence of PIK3CA and CCM mutations/phenotypes in CCM lesions. Finally, we present a model reflecting our hypothetical understanding of CCM pathogenesis based on a systematic review and conceptualisation of data obtained from other studies.

Intracranial venous malformations: Incidence and characterization in a large pediatric cohort

BACKGROUND

Significant advances have been reported recently in the genetic and mechanistic characterization of extracranial venous malformations. However, intracranial purely venous malformations (icVM) analogous to those outside the CNS have not been systematically described.

PURPOSE

We sought to ascertain whether such an entity as icVM could in fact be identified, distinct from previously described CNS venous anomalies and analogous to extracranial venous malformations.

METHODS

Our prospectively collected pediatric cerebrovascular database was reviewed to identify patients with icVM; 1458 consecutive angiograms and/or angiographic interventions performed on 706 children at our institution from October, 2006 through May, 2019 were evaluated, in addition to outside imaging studies on 192 additional patients sent to our Vascular Anomalies Center for cerebrovascular review during the same time period. Thus, the cohort consisted of 898 children.

RESULTS

Nineteen of 898 patients (2.1%) were found to harbor icVM, including 9 (47.3%) with sinus pericranii, 15 (78.9%) with associated large, complex extracranial venous malformations, and 3 (15.7%) with neurocognitive delay. There was no intracranial hemorrhage or venous hypertension seen in the cohort. Asymptomatic venous thrombosis in the superior sagittal sinus was seen in three patients.

CONCLUSION

Venous malformations, both extracranial and icVM, share many characteristics that are distinct from developmental venous anomalies. icVM were not associated with venous hypertension. The underlying genetic mutations involved in the development of icVM, germ-line or somatic, remain to be elucidated, but may very well involve shared mechanisms and pathways with extracranial venous malformations.

Hemorrhage owing to cerebral cavernous malformation: imaging, clinical, and histopathological considerations

Cavernous malformation (CM) is the second most common cerebral vascular malformation and is often found incidentally. Their natural history is usually benign, however, patients with CM who present with symptomatic hemorrhage may later follow a serious clinical course if left untreated. The risk of hemorrhage is associated with previous hemorrhage, lesion location (infratentorial and deep), and the presence of associated developmental venous anomaly (DVA). Histopathological specimens also indicate that coexistence of DVA and other vascular malformations may be associated with hemorrhage owing to CMs. Diagnosing CMs is difficult, even in patients who initially present with symptomatic hemorrhage. Computed tomography scans typically reveal a hemorrhagic CM as a nonspecific heterogenous mass of high density, which may not be misdiagnosed as a solitary hematoma, especially when located in the infratentorial region. Magnetic resonance imaging demonstrates internal loculation with mixed-signal intensities typical for CMs, although this may be partially or completely masked by acute hemorrhage. Susceptibility-weighted imaging (SWI) reveals a significant "blooming" effect of hemosiderin deposition. Three-dimensional postcontrast T1-weighted imaging is essential to identify associated DVAs, and this is important for both diagnosis and planning of surgical treatment. Contrast-enhanced MRI should be performed to diagnose hemorrhagic CMs and differentiate them from spontaneous solitary hematoma or hemorrhagic tumors.

Metabolic Changes of Brain Developmental Venous Anomalies on 18F-FDG-PET

RATIONALE AND OBJECTIVES

To determine the metabolic effects of developmental venous anomalies (DVAs) and to correlate those effects with conventional magnetic resonance imaging (MRI) findings.

MATERIALS AND METHODS

We conducted a retrospective review of MRI and brain 18F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET) examinations in subjects with DVAs. Conventional MRI was used to determine DVA number, location, size, and associated parenchymal findings such as atrophy, hemorrhage, cavernoma, capillary telangiectasia, cortical dysplasia/polymicrogyria, and white matter signal abnormality. Qualitative and quantitative measures of relative metabolism in the drainage territory of the DVA were measured on ¹⁸F-FDG-PET.

RESULTS

Fifty-four subjects with 57 DVAs were included in the analysis. 38% were associated with qualitative and quantitative metabolic abnormalities on ¹⁸F-FDG-PET, with decreased metabolism in the parenchyma surrounding all but one of these DVAs. DVAs draining gray matter were significantly more likely to be hypometabolic than those draining only white matter, suggesting that the metabolic effects of DVAs may be underestimated on ¹⁸F-FDG-PET.

CONCLUSION

Altered metabolism is seen in the drainage territory of a significant proportion of DVAs, suggesting that these anomalies are vascular lesions with abnormal physiologic features.

Clinical Management of Cavernous Malformations

PURPOSE OF REVIEW

This study aims to review the current epidemiology and clinical management of patients with cavernous malformations (CM).

RECENT FINDINGS

Hemorrhage is the most feared complication and leads to morbidity in patients with CM. Multiple studies including three meta-analyses have provided useful estimates of hemorrhage risk, but have failed to identify a modifiable risk factor for prevention of cavernous malformation related hemorrhage. In treating the CM itself, surgical risk is weighed against the natural history. However, accumulating knowledge regarding the roles of CCM 1, 2, and 3 genes has led to the discovery of potential therapeutic targets. The risk of future hemorrhage in patients with CM is highest in those who have had previously clinical hemorrhages. Estimated risks are helpful in counseling patients and comparing to the risk of surgery. Future clinical trials of candidate medications are likely to target those patients with prior clinical hemorrhage in whom the surgical risk is deemed high.

Treatment of an Arteriovenous Shunt Draining into a Venous Angioma by Selective Embolisation

We treated a 62-year-old woman who suffered from intraventricular haemorrhage. Angiography revealed an arteriovenous shunt draining into a venous angioma. She was successfully treated by obliteration of the arteriovenous shunt with transarterial embolisation.

Angiography performed after embolisation demonstrated that the persisting venous angioma served as the draning vein for normal middle cerebral artery perfusion.

We believe that selective arterial occlusion with preservation of the venous component is the best treatment for this type of mixed vascular malformation.

Developmental Venous Anomaly: Benign or Not Benign

Developmental venous anomalies (DVAs), previously called venous angiomas, are the most frequently encountered cerebral vascular malformations. However, DVA is considered to be rather an extreme developmental anatomical variation of medullary veins than true malformation. DVAs are composed of dilated medullary veins converging centripetally into a large collecting venous system that drains into the superficial or deep venous system. Their etiology and mechanism are generally accepted that DVAs result from the focal arrest of the normal parenchymal vein development or occlusion of the medullary veins as a compensatory venous system. DVAs per se are benign and asymptomatic except for under certain unusual conditions. The pathomechanisms of symptomatic DVAs are divided into mechanical, flow-related causes, and idiopathic. However, in cases of DVAs associated with hemorrhage, cavernous malformations (CMs) are most often the cause rather than DVAs themselves. The coexistence of CM and DVA is common. There are some possibilities that DVA affects the formation and clinical course of CM because CM related to DVA is generally located within the drainage territory of DVA and is more aggressive than isolated CM in the literature. Brain parenchymal abnormalities surrounding DVA and cerebral varix have also been reported. These phenomena are considered to be the result of venous hypertension associated with DVAs. With the advance of diagnostic imagings, perfusion study supports this hypothesis demonstrating that some DVAs have venous congestion pattern. Although DVAs should be considered benign and clinically silent, they can have potential venous hypertension and can be vulnerable to hemodynamic changes.

The Associated Venous Anomalies Variant and Adjacent Brain Function on Iron Sensitive Image Indicate Surgical Risk of Cavernous Malformation

The cavernous malformations (CMs) associated with venous anomalies (VAs) are now being described with increasing frequency. Assessment of the associated VAs is overlooked in surgical management of the CM. The clinical profiles of CMs with VAs were reviewed to investigate the value of T₂*gradient echo (GRE)/susceptibility weighted imaging (SWI) in surgical risk evaluation. Twenty-six patients with symptomatic CMs associated with VAs between 2008 and 2013 were identified. Demographic, clinical, and radiological data were reviewed and functional outcomes were assessed using the modified Rankin Scale (mRS). The T₂*GRE/SWI could allow more accurate evaluation of the boundary and drainage vicinity of VAs than contrast-enhanced images (6 vs. 2 patients with VAs on the eloquent region). Patients with VAs adjacent to eloquent brain showed poorer outcomes than those who had VAs in non-eloquent areas (P = 0.005), while the CMs adjacent to eloquent brain did not correlated with poor outcomes (P = 0.15). Type I and III variants of VAs were also significantly associated with poor outcomes, compared with type II variant (P = 0.002). Careful evaluation of VAs variant type and the association between VAs and eloquent brain is helpful for the management of CMs associated with VAs. We recommend T₂*GRE/SWI in patients with CMs to assess the associated VAs. The evaluation of VA drainage vicinity on T₂*GRE/SWI would be more useful for designing treatment strategies and risk stratification.

Cerebellar cavernous malformations with and without associated developmental venous anomalies

BACKGROUND

The clinical profiles of cerebellar cavernous malformations (CCMs) with and without associated developmental venous anomalies (DVAs) are not well known. The aims of this study were to analyze the clinical and radiological characteristics of CCMs and to assess the various therapeutic strategies.

METHODS

A consecutive series of 41 patients with identified CCMs were retrospectively reviewed. Of these, 11 patients (26.8%) were found to have associated DVAs. We compared the clinical profile of the two groups of patients (CCMs with and without DVAs). The CCMs with DVAs cases underwent radical resection of the CCMs, and the distal radicles of the DVAs that directly drain from the CCMs were coagulated and dissected at the length of the CCMs.

RESULTS

There were no statistically significant differences between the two groups with regard to age, sex, location and size of lesions, multiplicity, and surgical prognosis. The patients with CCMs with DVAs did not experience any brain swelling or hemorrhagic tendency intraoperatively. The postoperative course was uneventful for all of the 36 surgical patients with the exception of two of the patients with CCMs with associated DVAs, who suffered from serious cerebellar edema, and one of these two patients underwent an emergency suboccipital decompression craniotomy. With the exception of three patients who were lost to follow-up (mean, 22.3 months), all of the CCMs patients exhibited good long-term prognosis (modified Rankin scale values of 0-2) and no reoccurrence.

CONCLUSIONS

It is not rare that associated DVAs occur in CCMs. The total removal of the CCM combined with the coagulation and dissection of the distal radicles of DVA at the length of the associated CCM may result in good long-term prognosis in patients.

Parenchymal hypointense foci associated with developmental venous anomalies: evaluation by phase-sensitive MR Imaging at 3T

BACKGROUND AND PURPOSE

The risk of hemorrhage in the context of developmental venous anomaly is considered to be very low, but it has never been evaluated by susceptibility-weighted MR imaging at 3T. The goal of the present study was to evaluate the prevalence of hypointense foci (ie, microhemorrhage or cavernous malformation) associated with DVA on phase-sensitive MR imaging, on the basis of principles similar to those of susceptibility-weighted MR imaging, and to evaluate the relationship between the hypointense foci and several factors, such as white matter hyperintense lesions adjacent to DVA on T2-weighted imaging, DVA morphology, and clinical symptoms.

MATERIALS AND METHODS

This study retrospectively evaluated 61 lesions in 59 consecutive patients with DVA who underwent MR imaging including phase-sensitive MR imaging. Two neuroradiologists independently assessed for the presence of hypointense foci and other factors such as DVA location, depth, size, direction of draining vein on phase-sensitive MR imaging, and white matter hyperintense lesion on T2-weighted imaging. Clinical symptoms were also assessed.

RESULTS

Hypointense foci were observed in 62.3% (38/61) of lesions. White matter hyperintense lesion was more frequently observed in patients with hypointense foci (26/38) than in patients without hypointense foci (7/23) (P < .01). There was no significant association between hypointense foci and other factors.

CONCLUSIONS

Our results support the hypothesis that microhemorrhage or cavernous malformation can be related to venous congestion caused by abnormal venous drainage. We conclude that phase-sensitive MR imagingis useful for the detection of microhemorrhage or cavernous malformation in patients with DVA, especially when associated with white matter hyperintense lesion.

Normal and abnormal embryology and development of the intracranial vascular system

The brain vascular system develops in such a way that it continuously adapts the supply of oxygen and other nutrients to the needs of the parenchyma. To accompany the developing brain vesicles, it evolves in several steps: superficial meningeal network first; intraventricular choroid plexuses which determine the arterial pattern; penetrating capillaries from the surface to the ventricular germinal matrix forming simple transcerebral arteriovenous loops; cortical capillaries last, mainly in the last trimester. The venous return becomes connected to both the surface and to the choroidal veins, so forming distinct meningeal and subependymal venous drainage systems, while the arteries are on the surface only. While the arterial system was determined early (week 8), the venous system is continuously remodeled by the morphological changes of the base of the skull and the expansion of the brain vesicles. Until late in gestation, the vascular system is made of simple endothelial channels in which the arterial or venous fate is determined primarily by the direction of flow.

DEVELOPMENTAL VENOUS ANOMALIES

DEVELOPMENTAL VENOUS ANOMALIES (DVAs), formerly known as venous angiomas, have become the most frequently diagnosed intracranial vascular malformation. DVAs are currently considered congenital cerebrovascular anomalies with mature venous walls that lack arterial or capillary elements. They are composed of radially arranged medullary veins, which converge in an enlarged transcortical or subependymal collector vein, and have characteristic appearances (caput medusae) on magnetic resonance imaging and angiography. DVAs were once thought to be rare lesions with substantial potential for intracerebral hemorrhage and considerable morbidity. The prevalence of incidental and asymptomatic DVAs has been more apparent since the advent of magnetic resonance imaging; recent cohort studies have challenged the once-held view of isolated DVAs as the cause of major neurological complications. The previously reported high incidence of intracerebral hemorrhage associated with DVAs is currently attributed to coexistent, angiographically occult cavernous malformations. Some patients may still have noteworthy neurological morbidity or die as a result of acute infarction or hemorrhage directly attributed to DVA thrombosis. DVAs can coexist with cavernous malformations and arteriovenous malformations. Such combination or transitional forms of malformations might suggest common pathways in pathogenesis. Recent data support a key role for DVAs in the pathogenesis of mixed vascular malformations.

Repeated intracerebral hemorrhage from developmental venous anomaly alone

Developmental venous anomalies (DVAs) are hemodynamically low flow, low resistance vascular malformations without clinical significance. Although most DVAs are asymptomatic and are found incidentally, sometimes they can be symptomatic with intracerebral hemorrhage, many of which are usually caused by associated cavernous malformations (CMs) rather than the DVAs themselves. Only a few cases have been reported in the literature where an intracerebral hemorrhage has been caused by a DVA alone. This report describes a case of an intracerebral hemorrhage due to DVA alone with review of the literature.

[Developmental venous anomaly (DVA)]

As congenital anatomic variants of venous drainage, developmental venous anomalies (DVA) represent up to 60% of all cerebral vascular malformations. The prior term "venous angioma" is a misnomer implicating an abnormal vascular structure with an increased bleeding risk. They are often found incidentally and are hardly ever symptomatic. Their morphologic characteristics are dilated vessels in the white matter, which converge on a greater collector vein, forming the typical caput medusae. They drain into the superficial or deep venous system. The frequent association with other, potentially bleeding-prone vascular malformations is clinically relevant, in particular cavernous angioma, which might require therapeutic action. Therefore, coincident vascular lesions need to be actively sought by appropriate additional imaging techniques.

The neurovascular triad: mixed cavernous, capillary, and venous malformations of the brainstem

Object

The four types of cerebrovascular malformations may sometimes be combined and more often occur in pairs; triads are exceptional. The authors present six patients with the clinicoradiographic profile of mixed vascular malformations of the brainstem, including cavernous malformation (CM), capillary telangiectasia, and developmental venous anomaly (DVA).

Methods

Five patients (one of whom was a child) suffered from hemorrhage, suggesting that this complex association has a high bleeding potential. Progressive growth, rebleeding, and de novo occurrence of the associated CM were documented in three cases. Magnetic resonance imaging of the brain was obtained in all patients by using one or more of the following modalities: T1-weighted sequences before and after gadolinium administration; T2-weighted sequences; T2-weighted fluid attenuated inversion recovery; T1-weighted fast spin echo; and diffusion weighted, diffusion tensor, and perfusion imaging in three cases.

Results

Three patients were surgically treated with the intention of excising the hemorrhagic lesion, but only two patients had their malformations successfully removed. In the third case, diffuse pontine telangiectasia precluded the safe excision of the CM. Histological examination demonstrated a blended pathological milieu characterized by coalescent telangiectasia and venules associated with loculated endothelial chambers resembling an immature or de novo CM. Three patients were treated conservatively; recurrent minor hemorrhage occurred in one case. The authors found these malformations to be arranged in two basic relationships: CM inside the telangiectasia and CM in the radicles of the DVA. Stenosis of the main venous collector and dilation of the medullary veins were important findings.

Conclusions

The pathogenesis of this malformation may be referred to a developmental deviance of the brainstem capillary–venous network associated with transitional vessels and loculated endothelial vascular spaces related to genetic and acquired origins, probably in a restrictive venous outflow milieu.

Parenchymal abnormalities associated with developmental venous anomalies

INTRODUCTION

To report a retrospective series of 84 cerebral developmental venous anomalies (DVAs), focusing on associated parenchymal abnormalities within the drainage territory of the DVA.

METHODS

DVAs were identified during routine diagnostic radiological work-up based on magnetic resonance imaging (MRI) (60 cases), computed tomography (CT) (62 cases) or both (36 cases). Regional parenchymal modifications within the drainage territory of the DVA, such as cortical or subcortical atrophy, white matter density or signal alterations, dystrophic calcifications, presence of haemorrhage or a cavernous-like vascular malformation (CVM), were noted. A stenosis of the collecting vein of the DVA was also sought for.

RESULTS

Brain abnormalities within the drainage territory of a DVA were encountered in 65.4% of the cases. Locoregional brain atrophy occurred in 29.7% of the cases, followed by white matter lesions in 28.3% of MRI investigations and 19.3% of CT investigations, CVMs in 13.3% of MRI investigations and dystrophic calcification in 9.6% of CT investigations. An intracranial haemorrhage possibly related to a DVA occurred in 2.4% cases, and a stenosis on the collecting vein was documented in 13.1% of cases. Parenchymal abnormalities were identified for all DVA sizes.

CONCLUSION

Brain parenchymal abnormalities were associated with DVAs in close to two thirds of the cases evaluated. These abnormalities are thought to occur secondarily, likely during post-natal life, as a result of chronic venous hypertension. Outflow obstruction, progressive thickening of the walls of the DVA and their morphological organization into a venous convergence zone are thought to contribute to the development of venous hypertension in DVA.

Spontaneous occlusion of brainstem arteriovenous malformation following ligature of a hepatic patent ductus venosus. Case report and review of the literature

The authors describe the clinical and radiological findings in a case of brainstem arteriovenous malformation (AVM) associated with a hepatic patent ductus venosus (PDV) in a 12-year-old child. The AVM was discovered on magnetic resonance (MR) imaging performed because of slight mental retardation and headache. The malformation was otherwise asymptomatic and no treatment was proposed. An abdominal ultrasonography study performed 1 year later because of hyperammonemia revealed a PDV, which was surgically ligated. One year later, MR images and angiograms showed complete resolution of the brainstem AVM. This report is the first documentation of an association between these two entities in the same patient, and the possible pathophysiological interactions between them are discussed.

The association of venous developmental anomalies and cavernous malformations: pathophysiological, diagnostic, and surgical considerations

✓Developmental venous anomalies (DVAs) are often associated with intracranial cavernous malformations (CMs). The frequency of this association and the observation of de novo CMs located near a known, preexisting DVA raise speculations as to the possible etiopathogenetic relationship between the two. In this article, the authors review the recent literature dealing with the potential etiopathogenetic, prognostic, and therapeutic implications of the association between DVAs and CMs.

Cerebral Cavernous Malformations Associated with Venous Anomalies: Surgical Considerations

OBJECTIVE:

Once thought to be rare entities, mixed cerebrovascular malformations with pathological features of more than one type of malformation within the same lesion are now being recognized with increasing frequency. Their identification generates several hypotheses about common pathogenesis or causation-evolution among different types of lesions and leads to controversial discussion on therapeutic strategies.

METHODS:

Fifteen patients drawn from a consecutive series of 58 patients harboring cavernous malformations (25.9%) were found to have an associated venous malformation (VM). Three (33.3%) of the first 9 patients, in whom the large draining vein of the VM had been left untouched at previous interventions, developed recurrent and/or de novo lesions.

RESULTS:

Histopathological analysis, interestingly, revealed that the new lesions were different in nature (three arteriovenous angiomas in two patients, a capillary telangiectasia in one patient). During extirpation of the new malformation, the draining vein of the VM in these three patients could be coagulated without any adverse events. Coagulation and dissection of the draining vein of the associated VM was performed in six more patients of our series, and this has prevented development of new lesions up to now.

CONCLUSION:

Our results are in favor of the hypothesis that the draining vein of a VM is the actual underlying abnormality of mixed vascular malformations. Causing flow disturbances and having the potential for hemorrhages, the VM seems to promote the development of new adjacent malformations. Thus, permanent cure of associated malformations might depend on the surgical treatment of the VM. We present a preliminary personal series and a thorough review of the literature.

Thrombus and encapsulated hematoma in cerebral cavernous malformations

Thrombi, encapsulated hematomas, and granulation tissue are frequently seen in cerebral cavernous malformations (CCMs). We investigated the role that these histological changes play in repeated hemorrhages in CCMs as well as lesion growth, examining specimens of CCMs surgically harvested from 20 patients. The immunohistochemical study included thrombomodulin (TM) and endothelial cell protein C receptor (EPCR), which are important regulators of blood coagulation. Thick capsules, which contained blood degradation product, were seen in cases with encapsulated hematomas. Clusters of sinusoidal vessels were found outside of these thick capsules. Granulation tissue with inflammatory infiltrates and capillaries was seen in 4 cases with non-capsulated hematomas. Organizing thrombi were seen in sinusoidal vessels in 15 out of 20 cases. Factor VIII-related antigen staining demonstrated numerous capillaries in and around organizing thrombi and within the thickened vessel walls as well as in both the inner and outer sides of the hematoma capsule. TM and EPCR were positive in the endothelial cells of these capillaries, whereas they were negative in those of capillaries in the brain surrounding the lesions. Our study suggests that thrombosed sinusoidal blood vessels could gradually expand by repeated bleeding from numerous capillaries inside the wall and become encapsulated hematomas, and capillaries outside the thickened vessel wall could become sinusoidal blood vessels. Thrombosis within cerebral venules could be one of the causal factors of CCMs.

Surgical correction of symptomatic vertebral artery kinking

Two cases of repeated posterior fossa ischaemia are presented. Other sources of embolization, except middle part vertebral artery kinkings were excluded. Medical therapy failed in both cases. A simple surgical technique was employed--kink straightening and fixation. In both cases the surgery was simple, safe, yielding the desired effect.

Histologically classified venous angiomas of the brain: a controversy

The term "venous angioma" (VA) usually refers to a developmental venous anomaly (DVA). However, a group of vascular malformations called VAs shows no venous abnormalities on angiography. The clinical and histological features of histologically classified VAs were studied in eight patients who presented with hemorrhage or seizures to reevaluate these venous anomalies. Angiography showed no venous abnormalities in six patients. Histological study included immunostaining for smooth muscle actin and glial fibrillary acidic protein. Surgical specimens of 10 cases of cavernous angiomas, 10 cases of arteriovenous malformations, and two cases of capillary telangiectasias were studied to compare these types of VAs. Angiographically occult VAs were surgically removed safely, whereas removal of DVAs was complicated by brain swelling and hemorrhagic infarction of the brain. Histological examination found angiographically occult VAs contained malformed and compactly arranged vessels with partly degenerated walls, whereas DVAs had dilated thin-walled vessels that were diffusely distributed in the normal white matter. This study of our cases and a review of the reported cases of VAs suggests that two different clinical and pathological entities are commonly categorized as "VA," angiographically occult VAs and DVAs. These two entities should be carefully distinguished.

Development of a posterior fossa cavernous malformation associated with bilateral venous anomalies: case report

Venous angiomas (VAs) and cavernous malformations (CMs) are common cerebrovascular malformations. Frequently, these lesions are found in close proximity. The interrelationship between VAs and CMs has not yet been adequately defined. The authors report a case of a 48-year-old man with progressive dysarthria, dysmetria, and ataxia. Eight years previously, magnetic resonance imaging (MRI) revealed a solitary CM and bilateral posterior fossa VAs. Later imaging after neurological progression revealed the presence of 2 rather than 1 CM adjacent to the VAs. The sequential imaging suggests a causal relationship between VAs and some CMs. Furthermore, the detailed MRI permitted radiosurgical treatment of these CMs. The occurrence of de novo CMs adjacent to VAs on future imaging studies in other patients may help confirm the etiology of at least a subset of CMs.

The juxtaposition of a capillary telangiectasia, cavernous malformation, and developmental venous anomaly in the brainstem of a single patient: case report

OBJECTIVE AND IMPORTANCE

Capillary telangiectasias, cavernous malformations, and developmental venous anomalies are all vascular malformations that occur on the capillary-venous side of the cerebral circulation. The associations of capillary telangiectasias with venous malformations, cavernous malformations with venous malformations, and capillary telangiectasias with cavernous malformations have all been described; however, the association of all three lesions in a single patient is extremely rare.

CLINICAL PRESENTATION

A 52 year-old Caucasian woman presented to our clinic with an extended history of confusion, distorted visual perceptions, photophobia, neck pain, swallowing problems, and poor balance. The patient's examination was remarkable for difficulty concentrating, mild rotatory nystagmus, subtle decreased sensation over the left side of the face and body, and brisk reflexes. Review of the patient's magnetic resonance imaging examination demonstrated a cavernous malformation, a capillary telangiectasia, and a developmental venous anomaly located adjacent to one another in the brainstem.

INTERVENTION

Given the patient's complex constellation of symptoms and relatively mild neurological findings, it was difficult to ascribe any one of them to a specific vascular malformation. Conservative management of this patient's vascular malformations was decided upon.

CONCLUSION

Juxtaposition of these three different vascular lesions in the brainstem of an otherwise normal individual suggests a relationship among them. Although there are several theories that link similar associations through physiological mechanisms such as venous hypertension, we propose that a developmental event disrupting local capillary-venous pattern formation is a plausible alternative.

Thalamic cavernous malformations

BACKGROUND

Only few anecdotal reports and small series of thalamic cavernous malformations have been reported. It follows that the clinical behavior and management are poorly understood; in particular, experiences with the surgical treatment of these lesions are scarce.

METHODS

The clinical course, treatment, and outcome of 12 patients (10 females and 2 males, mean age 36 years) with symptomatic cavernous malformations of the thalamus are reviewed. Eight patients (66%) presented with cerebral hemorrhage, one with progressive neurological deficit and three with hydrocephalus/increased intracranial pressure; associated venous anomalies were found in three cases. Treatment consisted of radical surgery in four cases with progressive neurological decline or recurrent disabling hemorrhage, radiosurgery (one case), evacuation of a chronic satellite hematoma (one case), ventriculoperitoneal shunt for hydrocephalus (one case) and observation (five cases). Operative treatment in four cases included transcallosal, trigonal, and occipital interhemispheric approaches.

RESULTS

In the surgical group, one patient died, two improved after operation, and one remained the same. Of the patients not operated on radically, one had recurrent hemorrhage 4 months after radiosurgery, one remains stable 8 years after ventriculoperitoneal shunt, and one 3 years after aspiration of a satellite hematoma. Five other patients presenting with thalamic hemorrhage were treated conservatively; recurrent hemorrhage occurred in two cases at 1 month and at 2 years, leaving a mild residual deficit in both cases. Overall, rehemorrhage occurred in four cases (50%) at a mean interval of 18 months after the first bleeding; the annual hemorrhage rate was 6.1%.

CONCLUSIONS

Thalamic malformations are more likely to be symptomatic from small hemorrhages compared with lesions in the cerebral hemispheres; progressive growth may also occur with third ventricle invasion or caudal extension to the midbrain. Their high-risk location deters heavy-handed management, but they should not be left long untreated. Both surgery and radiosurgery have been used in the management of thalamic cavernomas reported in the literature. Definite surgical indications include progressive neurological decline and recurrent hemorrhages of malformations abutting the ventricular surface or the posterior incisural space; the complex anatomy of the deep venous system and the association with unexpected venous anomalies complicates the removal of these lesions.

A comparison of the clinical profile of cavernous malformations with and without associated venous malformations

OBJECTIVE

Little is known about the clinical behavior of cavernous malformations (CMs) associated with venous malformations (VMs) of the brain. The aim of this study is to compare the clinical profile of patients harboring CMs with and without associated VMs.

METHODS

A retrospective analysis of 55 consecutive patients harboring CMs of the brain who presented to a single neurovascular team during a 4-year period was performed. Forty-two patients (76%) had CMs alone (CM group), and 13 patients (24%) had CMs associated with VMs (CM + VM group). Detailed clinical information regarding each patient was gathered. Statistical analysis was performed using Fisher's exact test for binary variables and Mann-Whitney U test for continuous variables.

RESULTS

The lesion location was infratentorial for 19 of the 70 CMs (27%) in the CM group and for 14 of the 21 CMs (67%) in the CM + VM group (P = 0.001). Familial histories of CMs were documented for 7 of the 42 patients (17%) in the CM group and none of the 13 patients in the CM + VM group. There was a female-to-male gender bias of 1.6:1 in the CM group and 3.3:1 in the CM + VM group. Sixteen of the 42 patients (38%) in the CM group and 8 of the 13 patients (62%) in the CM + VM group presented with symptomatic hemorrhage. Seizure presentation was documented in 11 of the 42 patients (26%) in the CM group and in 1 of the 13 patients (8%) in the CM + VM group. Repeated symptomatic hemorrhage was diagnosed in 4 of the 42 patients (9.5%) in the CM group and in 3 of the 13 patients (23%) in the CM + VM group. There were no apparent differences in the mean age at presentation, lesion size, or multiplicity between the two groups.

CONCLUSION

Patients with CMs associated with VMs are more likely to be female patients, have associated symptomatic hemorrhage, have lesions in the posterior fossa (statistically significant), suffer from repeated symptomatic hemorrhage, and are less likely to present with seizures or to have familial histories when compared with patients with CMs alone. The possible mechanisms for these apparent differences in clinical profile are discussed.

The prospective natural history of cerebral venous malformations

OBJECTIVE

A 10-year prospective clinical and magnetic resonance imaging study was undertaken to determine the natural history of venous malformations. We assessed the hemorrhage rate and morbidity associated with venous malformations of the brain.

PATIENTS AND METHODS

From 1986 to 1996, 80 patients with venous malformations were referred to the University of Pittsburgh multidisciplinary vascular malformation study group for evaluation. Observation was recommended for all patients. Follow-up clinical information was obtained from patients or their referring physicians through questionnaire or phone conversation.

RESULTS

Twenty-two patients presented with neurological signs or symptoms that were thought to be related to the malformations (nine with headaches, four with seizures, three with sensory symptoms, three with motor deficits, two with trigeminal neuralgia, and one with an extrapyramidal disorder). Twenty-three patients presented with headaches that were not considered to be related to the malformations. The retrospective hemorrhage rate (from birth to study entry) was 0.61% (18 bleeds in 2,949 patient-years). Sixteen patients had sustained previous brain hemorrhage in the region of the venous malformations, two of whom had suffered subsequent hemorrhage. During the prospective follow-up period totaling 298 patient-years of clinical observation, two patients suffered hemorrhage (0.68% per year), but only one had a symptomatic bleed (0.34% per year). This patient had not hemorrhaged previously. One of these patients remained asymptomatic, whereas the second developed temporary worsening of facial paresthesias. No patient died as a result of the venous malformations.

CONCLUSION

The hemorrhage rate of a patient with venous malformations is similar to the rates presented in previous reports for patients with cavernous malformations without previous symptomatic hemorrhage. We think that hemorrhage in a patient with venous malformations may be related to an underlying but not yet documented cavernous malformation. Because of the low risk for new neurological events, we advocate conservative management. The risks associated with surgical intervention greatly exceed the low risk of morbidity related to venous malformation hemorrhage.

The pathogenesis of arteriovenous malformations: insights provided by a case of multiple arteriovenous malformations developing in relation to a developmental venous anomaly

OBJECTIVE AND IMPORTANCE

Developmental venous anomalies (DVAs) are common anomalies of intracranial venous drainage that may occur in conjunction with other cerebral vascular malformations. The present case raises important questions regarding the association between anomalous venous drainage patterns and the development of arteriovenous malformations (AVMs).

CLINICAL PRESENTATION

We present the case of a 24-year-old man with small AVMs fed by the superior cerebellar artery that drained directly into a large DVA of the cerebellum.

INTERVENTION

The patient was managed conservatively and returned 10 years later with recurrent symptoms. A repeat angiogram demonstrated spontaneous thrombosis of the previously documented AVMs; however, new AVMs at a different site that was also fed by the superior cerebellar artery and drained into the same DVA had appeared. The AVMs were completely embolized, and the DVA was left intact.

CONCLUSION

Recently, increasing attention has focused on the possible importance of venous outflow disturbance and venous hypertension in the pathogenesis and pathophysiology of AVMs. The potential mechanisms for this association and the implications of the present case are discussed, and the pertinent literature is reviewed.

Ossified and de novo cavernous malformations in the same patient

We report the case of a 44-year-old patient with a MRI scan showing a newly developed cavernoma after two highly calcified lesions had been excised surgically. Six other cavernous malformations had been followed by MR imaging over a 2-year period. The coexistence of the two extremes of cavernous malformations in terms of lesions development--de novo and ossified lesions has not been reported previously and has implications for both the follow-up and the natural history of these malformations. The potential for developing new cavernous malformations persists and does not seem to be related to the evolutional stage of pre-existing lesions. It is suggested that these patients need to be followed up by MRI on a regular basis.

Multiple radiation-induced intracranial lesions after treatment for pituitary adenoma. Case report

This 53-year-old man presented with a syncopal episode 31 years after undergoing craniotomy and external-beam radiation for a pituitary macroadenoma. A gadolinium-enhanced magnetic resonance (MR) image of the brain demonstrated a 2.5-cm enhancing mass in the right caudate region that had not been seen on previous studies. A stereotactically guided biopsy procedure was performed to obtain specimens from the mass, which were consistent with ependymoma. The MR image also revealed two additional lesions that appeared to be within the radiation fields: a right temporal meningioma and a left frontal cavernous malformation. A review of the literature found three previous reports in which ependymomas presented after radiation therapy.

Surgical resection of intramedullary spinal cord cavernous malformations: delayed complications, long-term outcomes, and association with cryptic venous malformations

OBJECTIVE

To examine outcomes and delayed complications after the surgical resection of intramedullary spinal cord (IMSC) cavernous malformations. The association of these lesions with cryptic intraparenchymal venous malformations at surgery also was analyzed.

METHODS

The records of 17 patients who underwent resection of their histologically verified IMSC cavernous malformations were analyzed. There were nine female and eight male patients (mean age, 40.1 yr). The locations of the cavernous malformations were as follows: cervical, eight; thoracic, eight; and conus medullaris, one. The mean follow-up period was 48.3 months. Immediate postoperative and long-term neurological outcomes were compared, and delayed complications were assessed.

RESULTS

The patients presented with radiculopathy (n = 6), myelopathy (n = 10), and conus medullaris syndrome (n = 1). Intraoperatively, 16 (94.1%) IMSC cavernous malformations were associated with cryptic venous malformations. Immediately after surgery, four (23.5%) patients worsened neurologically whereas one (5.9%) improved. At long-term follow-up, however, 10 (58.9%) patients had improved and only 1 (5.9%) remained worse. Four (23.5%) patients experienced delayed complications. Three had undergone incomplete resection and experienced subsequent hemorrhage, necessitating subsequent resection. Another patient developed radiological tethering of the thoracic spinal cord without clinical symptoms. Two of the three patients who had undergone subsequent resection developed symptomatic tethering of the cervical spinal cord. In one of the two patients, the tethering was associated with an iatrogenic cerebellar tonsillar herniation. Both patients required surgical intervention.

CONCLUSIONS

The frequent coexistence of IMSC cavernous malformations with cryptic venous malformations in this series indicates a need for operative vigilance to preserve these venous anomalies. Delayed complications were the result of incomplete resection. The resultant hemorrhage required reexploration, which led to tethering of the spinal cord. Most patients who underwent resection, however, had improved neurologically at long-term follow-up.

De novo formation of a central nervous system cavernous malformation: implications for predicting risk of hemorrhage. Case report and review of the literature

The authors present a documented sporadic de novo cavernous malformation of the central nervous system (CNS) in a patient undergoing follow-up magnetic resonance imaging after resection of an acoustic neuroma. The authors believe that this is the first report of a de novo cavernous malformation in a patient without a familial history of this disease or a history of treatment with cranial radiation. The occurrence of de novo lesions invalidates the common assumption that cavernous malformations are congenital lesions. The use of this assumption to calculate bleeding risks retrospectively in patients with cavernous malformations is likely to underestimate the risk of symptomatic hemorrhage significantly. Consequently, the de novo formation of cavernous malformations may be more common than appreciated and may explain the higher bleeding rates reported in prospective compared with retrospective studies of these lesions.

De novo formation of a central nervous system cavernous malformation: implications for predicting risk of hemorrhage

The authors present a documented sporadic de novo cavernous malformation of the central nervous system in a patient undergoing follow-up magnetic resonance imaging after resection of an acoustic neuroma. The authors believe that this is the first report of a de novo cavernous malformation in a patient without a familial history of this disease or a history of treatment with cranial radiation. The occurrence of de novo lesions invalidates the common assumption that cavernous malformations are congenital lesions. The use of this assumption to calculate bleeding risks retrospectively in patients with cavernous malformations is likely to underestimate the risk of symptomatic hemorrhage significantly. Consequently, the de novo formation of cavernous malformations may be more common than appreciated and may explain the higher bleeding rates reported in prospective compared with retrospective studies of these lesions.

Intracerebral capillary telangiectasia and venous malformation: a rare association

BACKGROUND

The vascular malformations of the brain have been classified into arteriovenous, venous, cavernous, and capillary malformations as four discrete entities. Various combinations of two discrete malformations in one lesion have been reported, some of which can be considered as established associations, while others appear to be very rare. Mixed vascular malformations evoke reflections on possible interrelations in the pathogenesis of the discrete components.

CASE DESCRIPTIONS

We report a case of intracerebral capillary telangiectasia associated with a venous malformation in a supratentorial paraventricular location in a 45-year-old woman with a history of headache. The capillary telangiectasia was diagnosed by stereotactic biopsy. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) strongly suggested the presence of a venous malformation by demonstrating a transcerebral draining vein running through the center of the capillary telangiectasia. The association of capillary telangiectasia and venous malformation has been reported only twice before and exclusively in the posterior fossa, as opposed to the more frequent, established associations of capillary telangiectasia and cavernous malformation, and venous malformation and cavernous malformation, respectively.

CONCLUSIONS

Against the background of the established associations, this rare observation possibly places capillary telangiectasias, cavernous malformations, and venous malformations within the spectrum of a single disease. The common pathogenetic role of a focal venous outflow obstruction is discussed.

Regional parenchymal enhancement with mixed cavernous/venous malformations of the brain

✓ With improvements in imaging technology, the detection of both cavernous malformations and venous malformations has increased markedly in recent years. Although much has been learned about the association of cavernous and venous malformations, important questions regarding the true nature of such a relationship remain unanswered. It has been proposed that certain venous malformations produce local venous hypertension with resultant microhemorrhage, growth factor release, and creation of cavernous malformations. The authors report on two patients with cerebellopontine venous malformations associated with cavernous malformations. Both patients demonstrated persistent regional parenchymal enhancement associated with the vascular malformations. In addition, both patients had significant clinical symptoms referable to the region of affected brain. This previously undescribed finding may represent an imaging correlate to the complex interaction among venous malformations, venous hypertension, and cavernous malformations.

Occult cerebrovascular malformations after irradiation

OBJECTIVE

It has recently been found that patients receiving cerebral irradiation can develop hemorrhagic dysangiogeneses simulating occult vascular malformations. To analyze this connection, we report on five patients with occult cerebrovascular malformations occurring after "standard" or focused irradiation performed for brain tumors in four patients and for a deep-seated cavernous angioma in one patient.

METHODS

All lesions were within the radiation ports. The time interval between irradiation and the detection of the occult vascular malformations varied from 3 to 9 years; the ratio of female to male patients was 4:1. Four patients were < 15 years old when first irradiated. Four patients presented with acute symptoms (headache, vomiting, focal signs) and one was asymptomatic when the lesions were first detected. Serial magnetic resonance imaging scans were available in four patients and a computed tomographic scan in the other patient.

RESULTS

The initial appearance was that of a hypointense T1-T2 focus; magnetic resonance imaging then revealed focal or multifocal T1 hyperintensity and T2 mixed signal intensity followed by a late ring of decreased signal intensity. Four patients were operated on and one was under neuroradiological monitoring. Histological features of these lesions included clusters of closely packed vascular spaces resembling cavernous malformations sometimes associated with a thrombosed thick-walled vein with intense hemosiderin deposition and fibroblastic proliferation; telangiectasic changes were also seen in the adjacent brain.

CONCLUSION

Increased awareness of occult cerebrovascular malformations is necessary, because their occurrence is not infrequent and they have hemorrhagic potential. Children receiving cerebral irradiation are at greater risk of this complication.

Intracranial cavernous malformations: lesion behavior and management strategies

Intracranial cavernous malformations are vascular anomalies consisting of endothelium-lined caverns filled with blood at various stages of thrombosis and organization and separated by a collagenous stroma devoid of mature vessel wall elements. They occur in an estimated 0.45 to 0.9% of the population, with male and female patients equally affected and all ages represented. They commonly manifest as seizures, gross intracranial hemorrhage, and focal neurological deficits. Lesions are frequently multiple in the same patient, and 10 to 30% are associated with familial clustering. Several reports have documented a dynamic clinical-radiological lesion behavior with de novo lesion genesis, intralesional and perilesional hemorrhage, and corresponding fluctuations in lesion size. Hemorrhagic risk and neurological disability seem to be related to multiple factors, including lesion location, age, gender, state of reproductive cycle, and previous hemorrhage. Lesions may behave aggressively with repetitive hemorrhages and cumulative disability or may remain quiescent for many years. Management strategies include expectant follow-up in patients with asymptomatic or inaccessible lesions, excision of symptomatic and accessible lesions, and radiosurgery of progressively symptomatic lesions in inoperable locations. Relevant disease-specific outcome parameters are proposed to guide clinical decisions and future research. Prospective, stratified, hypothesis-driven studies using rigorous epidemiological methods must be undertaken to delineate patient and lesion factors influencing clinical aggressiveness. Biological studies are essential to uncover strategies to predict and modify lesion behavior.