Cerebral cavernous malformations: clinical insights from genetic studies

Cavernous malformations

Cavernous malformations are relatively common intracerebral malformations of which we only became properly aware after the introduction of MRI. They may be sporadic or familial. Familial CMs may be multiple and new lesions appear over time requiring intermittent MR control. Many sporadic CMs have no symptoms. The commonest location is in the supratentorial cerebral parenchyma presenting with epilepsy. The best treatment is microsurgery. A small proportion are in the brainstem and may rebleed and even be lethal. Treatment includes microsurgery and radiosurgery. Microsurgery cures the patient but has substantial problems with complications, deterioration and partial removal. Radiosurgery has taken time to demonstrate that it can over 2 years substantially reduce the risk of rebleeds without the risks of microsurgery. Both methods have a part to play in the treatment.

Cerebrovascular Anomalies: Perspectives From Immunology and Cerebrospinal Fluid Flow

Appropriate vascular function is essential for the maintenance of central nervous system homeostasis and is achieved through virtue of the blood-brain barrier; a specialized structure consisting of endothelial, mural, and astrocytic interactions. While appropriate blood-brain barrier function is typically achieved, the central nervous system vasculature is not infallible and cerebrovascular anomalies, a collective terminology for diverse vascular lesions, are present in meningeal and cerebral vasculature supplying and draining the brain. These conditions, including aneurysmal formation and rupture, arteriovenous malformations, dural arteriovenous fistulas, and cerebral cavernous malformations, and their associated neurological sequelae, are typically managed with neurosurgical or pharmacological approaches. However, increasing evidence implicates interacting roles for inflammatory responses and disrupted central nervous system fluid flow with respect to vascular perturbations. Here, we discuss cerebrovascular anomalies from an immunologic angle and fluid flow perspective. We describe immune contributions, both common and distinct, to the formation and progression of diverse cerebrovascular anomalies. Next, we summarize how cerebrovascular anomalies precipitate diverse neurological sequelae, including seizures, hydrocephalus, and cognitive effects and possible contributions through the recently identified lymphatic and glymphatic systems. Finally, we speculate on and provide testable hypotheses for novel nonsurgical therapeutic approaches for alleviating neurological impairments arising from cerebrovascular anomalies, with a particular emphasis on the normalization of fluid flow and alleviation of inflammation through manipulations of the lymphatic and glymphatic central nervous system clearance pathways.

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.

Epidemiology of cavernous malformations

Cavernous malformations, accounting for approximately 5-15% of all vascular abnormalities in the central nervous system, are angiographically occult lesions which most often present with seizures, rather than acute hemorrhage. Widely variable across populations, the incidence of cavernous malformations has been reported to be 0.15-0.56 per 100 000 persons per year, with an annual hemorrhage rate of 0.6-11% per patient-year. Seen in 0.17-0.9% of the population, up to one-half are familial, and at least three gene loci have been associated with a familial form, more common among Hispanic Americans. Most cavernous malformations are supratentorial, with 10-23% in the posterior fossa, and approximately 5% found in the spine.

Pathological Evaluation of Radiation-Induced Vascular Lesions of the Brain: Distinct from De Novo Cavernous Hemangioma

PURPOSE

We aimed to evaluate the histologic and radiologic findings of vascular lesions after stereotactic radiosurgery (SRS) categorized as radiation-induced cavernous hemangioma (RICH).

MATERIALS AND METHODS

Among 89 patients who underwent neurosurgery for cavernous hemangioma, eight RICHs from 7 patients and 10 de novo CHs from 10 patients were selected for histopathological and radiological comparison.

RESULTS

Histologically, RICHs showed hematoma-like gross appearance. Microscopically, RICH exhibited a hematoma-like area accompanied by proliferation of thin-walled vasculature with fibrin deposits and infiltrating foamy macrophages. In contrast, CHs demonstrated localized malformed vasculature containing fresh and old clotted blood on gross examination. Typically, CHs consisted of thick, ectatic hyalinized vessels lined by endothelium under a light microscope. Magnetic resonance imaging of RICHs revealed some overlapping but distinct features with CHs, including enhancing cystic and solid components with absence or incomplete popcorn-like appearance and partial hemosiderin rims.

CONCLUSION

Together with histologic and radiologic findings, RICH may result from blood-filled space after tissue destruction by SRS, accompanied with radiation-induced reactive changes rather than vascular malformation. Thus, the term "RICH" would be inappropriate, because it is more likely to be an inactive organizing hematoma rather than proliferation of malformed vasculature.

The association between cerebral developmental venous anomaly and concomitant cavernous malformation: an observational study using magnetic resonance imaging

Background

Some studies reported that cerebral developmental venous anomaly (DVA) is often concurrent with cavernous malformation (CM). But there is lack of statistical evidence and study of bulk cases. The factors associated with concurrency are still unknown. The purpose of this study was to determine the prevalence of concomitant DVA and CM using observational data on Chinese patients and analyze the factors associated with the concurrency.

Methods

The records of all cranial magnetic resonance imaging (MRI) performed between January 2001 and December 2012 in Beijing Tiantan Hospital were reviewed retrospectively. The DVA and CM cases were selected according to imaging reports that met diagnostic criteria. Statistical analysis was performed using the Pearson chi-square statistic for binary variables and multivariable logistic regression analysis for predictors associated with the concurrent CM.

Results

We reviewed a total of 165,230 cranial MR images performed during the previous 12 year period, and identified 1,839 cases that met DVA radiographic criteria. There were 205 patients who presented concomitant CM among the 1,839 DVAs. The CM prevalence in DVA cases (11.1%) was significantly higher than that in the non-DVA cases (2.3%) (P<0.01). In the multivariate analysis, we found that DVAs with three or more medullary veins in the same MRI section (adjusted OR = 2.37, 95% CI: 1.73-3.24), infratentorial DVAs (adjusted OR = 1.71, 95% CI: 1.26-2.33) and multiple DVAs (adjusted OR = 2.08, 95% CI: 1.04-4.16) have a higher likelihood of being concomitant with CM.

Conclusions

CM are prone to coexisting with DVA. There is a higher chance of concurrent CM with DVA when the DVA has three or more medullary veins in the same MRI scanning section, when the DVA is infratentorial, and when there are multiple DVAs. When diagnosing DVA cases, physicians should be alerted to the possibility of concurrent CM.

Microsurgical or radiosurgical management of intracranial cavernomas

Cranial cavernous malformations (CCMs) constitute a heterogeneous group of lesions that tend to change dynamically over time with related periods of repeated exacerbation and alternating periods of remission. The decision on their management is based on estimating the inherent risk of further morbidity and the risk/benefit related to the particular treatment mode. Incidentally detected CCMs or lesions in asymptomatic patients presenting without major hemorrhage are best followed up. Complete resection of a CCM is the only healing option and is indicated for symptomatic or hemorrhagic lesions. In the large published series 83-92 % of the patients improved or remained unchanged after surgery, with only 8-11 % showing significant deterioration. For most patients, quality of life is improved. Analysis of the risk/benefit ratio for radiosurgery shows that it should not be regarded as an alternative option: It confers limited protection against bleeding and is related to a certain morbidity risk. In the subgroup of patients with symptomatic or hemorrhagic CCMs in locations that preclude surgical resection with acceptable risks, we recommend follow-up. The senior author is following a group of more than 80 such patients, and the vast majority remain free of hemorrhage and symptoms.

Familial versus sporadic cavernous malformations: differences in developmental venous anomaly association and lesion phenotype

BACKGROUND AND PURPOSE

CCMs are commonly associated with DVAs, but the incidence of association in familial CCM is unknown. The presence of a DVA significantly complicates surgical management of a CCM because of the risk of compromised venous drainage. In this investigation, we compared the incidence of a DVA in the presence of a CCM in sporadic and familial CCM cases comprising predominantly familial CCM with the Southwestern US common Hispanic mutation (or Q455X mutation) of CCM1.

MATERIALS AND METHODS

Retrospective review was performed of 112 patients identified with CCM. MR imaging review included the presence or absence of a DVA and number, location, size, and signal-intensity characteristics of CCMs. Record review included patient and family history and documented genetic mutations. Statistical analysis was performed by using the Fisher exact and 2-sample t tests.

RESULTS

Eighty-one cases were familial, 18 were sporadic, and 13 were indeterminate. There were a total of 2212 CCMs: 2176, 21, and 15 in the familial, sporadic, and indeterminate groups, respectively. There was a close association of CCM and DVA (an apparent combined vascular lesion) in 8 of 18 (44%) sporadic cases and only 1 possible such association in the familial cases. The difference was highly statistically significant (P < .0001).

CONCLUSIONS

Familial CCMs are unlikely to be associated with DVAs, and sporadic CCMs have a high rate of association with DVA. This difference in imaging features of familial and sporadic CCMs suggests the possibility of a different developmental mechanism.

Stroke in minorities

Minorities in the United States have higher stroke risks, stroke occurrence at an earlier age, and for some groups, more severe strokes than non-Hispanic whites. Factors contributing to these disparities are explored. Characteristics of African American, Hispanic, and Native American stroke risk and incidence are reviewed. The authors describe recent interventions to raise the awareness of stroke risk factors and symptoms in minorities. The importance of the problem is highlighted, and the authors suggest ways that stroke in minorities may be reduced.

Infantile dural arteriovenous shunt draining into a developmental venous anomaly

SUMMARY

A three-year-old girl with an incidentally discovered infantile type of dural arteriovenous shunts (DAVs) along the superior sagittal sinus during investigation of a minor head trauma is presented. The DAVs drained into a developmental venous anomaly of the right cerebral hemisphere. In addition, there was a small cavernoma within the territory drained by the DVA. The patient underwent multiple transarterial embolizations to decrease the shunt flow and thus the constrained venous drainage of the DVA and right cerebral hemisphere. Pediatric dural arteriovenous shunts are a different entity from the adult type DAVs and should be managed according to the growth and development of the child. DVAs are extreme variations of the venous system with reduced flexibility to increased venous drainage. Regardless of the type of treatment employed, the DVA and its drainage pathway must be preserved.