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 - An overview on genetics, clinical aspects and therapeutic strategies

Cerebral cavernous malformations (CCMs) are abnormally packed blood vessels lined with endothelial cells, that do not exhibit intervening tight junctions, lack muscular and elastic layers and are usually surrounded by hemosiderin and gliosis. CCMs may be sporadic or familial autosomal dominant (FCCMs) caused by loss of function mutations in CCM1 (KRIT1), CCM2 (MGC4607), and CCM3 (PDCD10) genes. In the FCCMs, patients have multiple CCMs, different family members are affected, and developmental venous anomalies are absent. CCMs may be asymptomatic or may manifest with focal neurological deficits with or without associated hemorrhage andseizures. Recent studies identify a digenic "triple-hit" mechanism involving the aquisition of three distinct genetic mutations that culminate in phosphatidylinositol-3-kinase (PIK3CA) gain of function, as the basis for rapidly growing and clinically symptomatic CCMs. The pathophysiology of CCMs involves signaling aberrations in the neurovascular unit, including proliferative dysangiogenesis, blood-brain barrier hyperpermeability, inflammation and immune mediated processes, anticoagulant vascular domain, and gut microbiome-driven mechanisms. Clinical trials are investigating potential therapies, magnetic resonance imaging and plasma biomarkers for hemorrhage and CCMs-related epilepsy, as well as different techniques of neuronavigation and neurosonology to guide surgery in order to minimize post-operatory morbidity and mortality. This review addresses the recent data about the natural history, genetics, neuroimaging and therapeutic approaches for CCMs.

Assessing the Relationship between Surgical Timing and Postoperative Seizure Outcomes in Cavernoma-Related Epilepsy: A Single-Institution Retrospective Analysis of 63 Patients with a Review of the Literature

Background: Patients with supratentorial cavernous malformations (SCMs) commonly present with seizures. First-line treatments for cavernoma-related epilepsy (CRE) include conservative management (antiepileptic drugs (AEDs)) and surgery. We compared seizure outcomes of CRE patients after early (≤6 months) vs. delayed (>6 months) surgery. Methods: We compared outcomes of CRE patients with SCMs surgically treated at our large-volume cerebrovascular center (1 January 2010-31 July 2020). Patients with 1 sporadic SCM and ≥1-year follow-up were included. Primary outcomes were International League Against Epilepsy (ILAE) class 1 seizure freedom and AED independence. Results: Of 63 CRE patients (26 women, 37 men; mean ± SD age, 36.1 ± 14.6 years), 48 (76%) vs. 15 (24%) underwent early (mean ± SD, 2.1 ± 1.7 months) vs. delayed (mean ± SD, 6.2 ± 7.1 years) surgery. Most (32 (67%)) with early surgery presented after 1 seizure; all with delayed surgery had ≥2 seizures. Seven (47%) with delayed surgery had drug-resistant epilepsy. At follow-up (mean ± SD, 5.4 ± 3.3 years), CRE patients with early surgery were more likely to have ILAE class 1 seizure freedom and AED independence than those with delayed surgery (92% (44/48) vs. 53% (8/15), p = 0.002; and 65% (31/48) vs. 33% (5/15), p = 0.03, respectively). Conclusions: Early CRE surgery demonstrated better seizure outcomes than delayed surgery. Multicenter prospective studies are needed to validate these findings.

Incidence of Cerebral Cavernous Malformation-Related Epilepsy in Children: A Single Center Survey

INTRODUCTION

Cerebral cavernous malformations (CCMs) are rare developmental cerebrovascular malformations. The risk of epilepsy is high in patients with CCMs, but the incidence of epilepsy has not been reported in a pure pediatric population. We herein present 14 pediatric cases of CCMs, including five with CCM-related epilepsy, and examine the incidence of CCM-related epilepsy in this pediatric population.  Methods: Pediatric patients with CCMs who visited our Hospital between November 1, 2001, to September 31, 2020, were retrospectively screened for inclusion, and 14 were enrolled.  Results: Fourteen enrolled patients were divided into two groups based on the presence or absence of CCM-related epilepsy. The "CCM-related epilepsy group" (n = 5) consisted of five males with a median age of 4.2 (range: 0.3-8.5) years at the first visit. The "non-epilepsy group" (n = 9) consisted of seven males and two females with a median age of 3.5 (range: 1.3-11.5) years at the first visit. The prevalence of CCM-related epilepsy at the time of the present analysis was 35.7%. Follow-up periods in CCM-related epilepsy and non-epilepsy groups were 19.3 and 24.9 patient-years, respectively: the incidence was 11.3% per patient-years. The frequency of seizures due to intra-CCM hemorrhage as the primary symptom was significantly higher in the CCM-related epilepsy group than in the non-CCM-related epilepsy group (p = 0.01). Other clinical characteristics, i.e., primary symptoms including vomiting/nausea and spastic paralysis, magnetic resonance imaging findings, including the number or maximum diameter of CCMs, cortical involvement, intra-CCM hemorrhage, and infratentorial lesions, surgical resection, and non-epileptic sequelae, such as motor disability and intellectual disability, did not significantly differ between the groups.  Discussion: The incidence of CCM-related epilepsy in the present study was 11.3% per patient year, higher than in adults. This discrepancy may be attributed to these studies including both adult and pediatric patients, whereas the present study examined a pure pediatric population. The presence of seizures due to intra-CCM hemorrhage as the initial symptom was a risk factor for CCM-related epilepsy in the present study. To elucidate the pathophysiology of CCM-related epilepsy or the reason for its higher incidence in children than in adults, further analyses of a large number of children with CCM-related epilepsy are warranted.

Clinical characteristics and risk factors of cerebral cavernous malformation-related epilepsy

PURPOSE

This study aimed to summarize the clinical characteristics and explore the risk factors for cerebral cavernous malformation (CCM)-related epilepsy (CRE).

METHODS

We retrospectively analyzed the clinical data of patients with CCM in our cerebral vascular malformations database. Descriptive statistics were used to present the clinical characteristics of CRE patients. Patients were divided into a CRE and a non-CRE group according to clinical presentation. Binary logistic regression analysis was used to analyze the risk factors of CRE.

RESULTS

A total of 199 patients with CCM confirmed by postoperative pathological examination were enrolled, 93 of whom were diagnosed with CRE, and 34 patients had drug-resistant epilepsy. The most common seizure type of CRE patients was focal to bilateral tonic-clonic seizure (FBTCS), followed by focal impaired awareness motor seizure. All CCM lesions were supratentorial, 97.8% of which involved the cerebral cortex, 86.0% of lesions had hemosiderin rim, and 50.5% of lesions were located in the temporal lobe. Binary logistic regression analysis indicated that CCM diagnosis age ≤ 44 years (odds ratio [OR] 2.79, p = 0.010), temporal lobe lesion location (OR = 9.07, p = 0.042), medial temporal lobe lesion (OR = 14.09, p = 0.002), cortical involvement of the lesion (OR = 32.77, p = 0.010), and hemosiderin rim around the lesion (OR = 16.48, p = 0.001) significantly increased the risk of CRE.

CONCLUSIONS

The most common seizure type of CRE was FBTCS. Those whose CCM diagnosis age was ≤ 44 years, having a temporal lobe lesion location, especially the medial temporal lobe lesion, cortical involvement, and hemosiderin rim around the lesion had a higher risk of developing CRE.

Radiosurgery effects and adverse effects in symptomatic eloquent brain-located Cavernomas

In this study, the dose schedule efficacy, safety and late adverse effects of stereotactic radiosurgery (SRS) were evaluated for patients with symptomatic cavernomas who were not eligible for surgery and treated with SRS. Between January 2013 and December 2018, 53 patients with cavernomas were treated using SRS with the CyberKnife® system. Patients' diseases were deeply located or were in subcortical functional brain regions. In addition to bleeding, 23 (43.4%) patients had epilepsy, 12 (22.6%) had neurologic symptoms and 16 patients (30.2%) had severe headaches. The median volume was 741 (range, 421-1351) mm3, and the median dose was 15 (range, 14-16) Gy in one fraction. After treatment, six (50%) of 12 patients with neurologic deficits still had deficits. Rebleeding after treatment developed in only two (3.8%) patients. The drug was completely stopped in 14 (60.9%) out of 23 patients who received epilepsy treatment, and the dose of levetiracetam decreased from 2000 mg to 1000 mg in four (17.3%) of nine patients. Radiologically, complete response (CR) was observed in 13 (24.5%) patients, and partial responses (PR) were observed in 32 (60.2%) patients. Clinical response of CR was observed in 30 (56.6%) patients, PR was observed in 16 (30.2%), stable disease (SD) was observed in three (5.7%) and four (7.5%) patients progressed. In conclusion, SRS applied in the appropriate dose schedule may be an effective and reliable method in terms of symptom control and prevention of rebleeding, especially in patients with inoperable cavernomas.

Evaluating the Role of Perilesional Tissue in Pathobiology of Epileptogenesis of Vascular Malformations of the Central Nervous System

Background and Purpose

Seizures are common presentation of cerebral vascular malformation (CVM). Topography and haemodynamic alterations are proposed as mechanisms for epileptogenesis, but the role of glial/neuronal alterations in perilesional tissue has not received much attention. Identification of the exact pathophysiologic basis could have therapeutic implications. To evaluate whether angioarchitectural factors of CVM or alterations in neuroglial/stroma of the adjacent cortex contribute to seizures.

Method

The clinical, imaging and histological characteristics of arteriovenous malformation (AVM) and cerebral cavernous malformation (CCM) with and without seizures was evaluated using neuroimaging imaging and digital subtraction angiography parameters and histopathology by morphology and immunohistochemistry.

Results

Fifty-six cases of CVM were diagnosed over a 2-year study period. Of these, 32 had adequate perilesional tissue for evaluation (AVM, 24; CCM, 8). Seizures at presentation was seen in 12/24 (50%) of AVM and 5/8 (62.5%) CCM. In AVM, hemosiderin deposition and gliosis in parenchyma (p=0.01) had significant association with seizure. Siderotic vessels in the adjacent cortex was exclusively seen only in CCM with seizures (p=0.018). Angioarchitectural features of CVM on imaging and neuronal alterations in adjacent cortex on histology failed to show any statistically significant difference between the two groups (p>0.05).

Conclusions

We propose that changes in adjacent cortex appear to be epileptogenic rather than the malformation per se. Reactive gliosis and hemosiderin deposits in perilesional tissue in AVM and siderotic vessels in CCM were associated with seizure. This explains the better outcomes following extended lesionectomy that includes epileptogenic perilesional tissues.

Quality of life and mood assessment in conservatively treated cavernous malformation-related epilepsy

BACKGROUND

To estimate the quality of life, anxiety, depression, and illness perception in patients with medically treated cerebral cavernous malformation (CCM) and associated epilepsy.

METHODS

Nonsurgically treated patients with CCM-related epilepsy (CRE) were included. Demographic, radiographic, and clinical features were assessed. All participants received established questionnaires (short-form 36 health survey, SF-36; hospital anxiety and depression score, HADS-A/D; visual analogue scale score, VAS) assessing the functional and psychosocial burden of disease. To some extent, calculated values were compared with reference values from population-based studies. Test results were related to seizure control.

RESULTS

A total of 37 patients were included. Mean age was 45.8 ± 14.4 years, and 54.1% were female. Diagnosis of CRE was significantly associated with attenuated quality of life and increased level of anxiety, affecting physical and psychosocial dimensions. The assessment of illness perception identified considerable burden. HADS was significantly associated with VAS and SF-36 component scores. Efficacy of antiepileptic medication had no restoring impact on quality of life, anxiety, depression, or illness perception.

CONCLUSIONS

CRE negatively influences quality of life and mood, independent of seizure control due to antiepileptic medication. Screening for functional and psychosocial deficits in clinical practice might be useful for assessing individual burden and allocating surgical or drug treatment.

Clinical characteristics and long-term outcome of cerebral cavernous malformations-related epilepsy

OBJECTIVE

Cerebral cavernous malformations (CCMs) present variably and epileptic seizures are the most common symptom. The factors contributing to cavernoma-related epilepsy (CRE) and drug resistance remain inconclusive. The outcomes of CRE after different treatment modalities have not yet been fully addressed. This study aimed to characterize the clinical features of patients with CRE and the long-term seizure outcomes of medical and surgical treatment strategies.

METHODS

This was a retrospective cohort of 135 patients with CCM who were diagnosed in 2007~2011 and followed up for 93.6 months on average. The patients were divided into drug-resistant epilepsy (DRE) (n = 29), non-DRE (NDRE) (n = 45), and no epilepsy (NE) (n = 61).

RESULTS

Temporal CCM was the factor most strongly associated with the development of both CRE and DRE. The majority of patients with single temporal CCMs had CRE (86.8%, n = 33) and 50% had DRE, whereas only 14.7% (n = 5) with a non-temporal supratentorial CCM had DRE (P < 0.05). The most common lesion site in the DRE group was the mesiotemporal lobe (50%). Multiple CCMs were more frequently observed in the CRE (29.2%) than the NE (11.5%) group (P < 0.05). In patients with CRE, multiple lesions were associated with a higher rebleeding rate (odds ratio: 11.1), particularly in those with DRE (odds ratio: 15.4). The majority of patients who underwent resective surgery for DRE (76.5%, n = 13) achieved ILAE class I and II seizure outcomes even after a long disease course.

SIGNIFICANCE

Temporal CCM not only predisposes to CRE but is also a major risk factor for drug resistance. The mesiotemporal lobe is the most epileptogenic zone. Multiple CCMs are another risk factor for CRE and increase the rebleeding risk in these patients. Surgical resection could provide beneficial long-term seizure outcomes in patients with DRE.

Long-Term Management of Seizures after Surgical Treatment of Supratentorial Cavernous Malformations : A Retrospective Single Centre Study

Objective

Seizure recurrence after the first-ever seizure in patients with a supratentorial cerebral cavernous malformation (CCM) is almost certain, so the diagnosis and treatment of epilepsy is justified. The optimal method of management of these patients is still a matter of debate. The aim of our study was to identify factors associated with postoperative seizure control and assess the surgical morbidity rate.

Methods

We retrospectively analysed 45 consecutive patients with a supratentorial CCM and symptomatic epilepsy in a single centre. Pre- and postoperative epidemiological data, seizure-related patient histories, neuroimaging results, surgery details and outcomes were obtained from hospital medical records. Seizure outcomes were assessed at least 12 months after surgery.

Results

Thirty-five patients (77.8%) were seizure free at the long-term follow-up (Engel class I); six (13,3%) had rare, nocturnal seizures (Engel class II); and four (8.9%) showed meaningful improvement (Engel class III). In 15 patients (33%) in the Engel I group; it was possible to discontinue antiepileptic medication. Although there was not statistical significance, our results suggest that patients can benefit from early surgery. No deaths occurred in our study, and mild postoperative neurologic deficits were observed in two patients (4%) at the long-term follow-up.

Conclusion

Surgical resection of CCMs should be considered in all patients with a supratentorial malformation and epilepsy due to the favourable surgical results in terms of the epileptic seizure control rate and low postoperative morbidity risk, despite the use of different predictors for the seizure outcome.

Semiology, EEG, and neuroimaging findings in temporal lobe epilepsies

Temporal lobe epilepsy (TLE) is the most common type of focal epilepsy. First descriptions of TLE date back in time and detailed portraits of epileptic seizures of temporal origin can be found in early medical reports as well as in the works of various artists and dramatists. Depending on the seizure onset zone, several subtypes of TLE have been identified, each one associated with peculiar ictal semiology. TLE can result from multiple etiological causes, ranging from genetic to lesional ones. While the diagnosis of TLE relies on detailed analysis of clinical as well as electroencephalographic (EEG) features, the lesions responsible for seizure generation can be highlighted by multiple brain imaging modalities or, in selected cases, by genetic investigations. TLE is the most common cause of refractory epilepsy and despite the great advances in diagnostic tools, no lesion is found in around one-third of patients. Surgical treatment is a safe and effective option, requiring presurgical investigations to accurately identify the seizure onset zone (SOZ). In selected cases, presurgical investigations need intracerebral investigations (such as stereoelectroencephalography) or dedicated metabolic imaging techniques (interictal PET and ictal SPECT) to correctly identify the brain structures to be removed.

Displacement of Gray Matter and Incidence of Seizures in Patients with Cerebral Cavernous Malformations

Seizures are the most common presentation in patients with cerebral cavernous malformations (CCMs). Based on the hypothesis that the volume or proportion of gray matter (GM) displaced by CCMs is associated with the risk of seizure, we developed an algorithm by which to quantify the volume and proportion of displaced GM and the risk of seizure. Image analysis was conducted on 111 patients with solitary CCMs (divided into seizure and nonseizure groups) from our gamma knife radiosurgery (GKRS) database from February 2005 and March 2020. The CCM algorithm proved effective in quantifying the GM and CCM using T1WI MRI images. In the seizure group, 11 of the 12 patients exhibited seizures at the initial presentation, and all CCMs in the seizure group were supratentorial. The location of the limbic lobe within the CCM was significantly associated with the risk of seizure (OR = 19.6, p = 0.02). The risk of seizure increased when the proportion of GM displaced by the CCM exceeded 31%. It was also strongly correlated with the volume of displaced GM. The volume and proportion of displaced GM were both positively correlated with the risk of seizure presentation/development and thus could be used to guide seizure prophylaxis in CCM patients.

Seizure Incidence Rates in Children and Adults With Familial Cerebral Cavernous Malformations

BACKGROUND AND OBJECTIVES

Seizure incidence rates related to familial cerebral cavernous malformation (FCCM) are not well described, especially for children. To measure the seizure incidence rate, examine seizure predictors, and characterize epilepsy severity, we studied a cohort of children and adults with FCCM enrolled in the Brain Vascular Malformation Consortium (BVMC).

METHODS

Seizure data were collected from participants with FCCM in the BVMC at enrollment and during follow-up. We estimated seizure probability by age and tested whether cerebral cavernous malformation (CCM) counts or genotype were associated with earlier seizure onset.

RESULTS

The study cohort included 479 FCCM cases. Median age at enrollment was 42.5 years (interquartile range 22.5-55.0) and 19% were children (<18 years old). Median large CCM count was 3 (interquartile range 1-5). Among 393 with genotyping, mutations were as follows: CCM1 (Common Hispanic Mutation) (88%), another CCM1 mutation (5%), CCM2 mutations (5%), and CCM3 mutations (2%). Prior to or during the study, 202 (42%) had a seizure. The cumulative incidence of a childhood seizure was 20.3% (95% confidence interval [CI] 17.0-23.4) and by age 80 years was 60.4% (95% CI 54.2-65.7). More total CCMs (hazard ratio [HR] 1.24 per SD unit increase, 95% CI 1.1-1.4) or more large CCMs (HR 1.5 per SD unit increase, 95% CI 1.2-1.9) than expected for age and sex increased seizure risk. A CCM3 mutation also increased risk compared to other mutations (HR 3.11, 95% CI 1.15-8.45). Individuals with a seizure prior to enrollment had increased hospitalization rates during follow-up (incidence rate ratio 10.9, 95% CI 2.41-49.32) compared to patients without a seizure history.

DISCUSSION

Individuals with FCCM have a high seizure incidence and those with more CCMs or CCM3 genotype are at greater risk. Seizures increase health care utilization in FCCM.

Reactive astrocytes contribute to epileptogenesis in patients with cavernous angioma

OBJECTIVE

Patients with cavernous angioma (CA) often suffer from severe epilepsy, and surgical resection is often performed to attenuate these epileptic seizures. Several studies have suggested that surgical removal of the surrounding hemosiderin-pigmented tissues adjacent to CA achieves better seizure control than restricted lesionectomy. Pathological examination of the resected foci reveals not only hemosiderin pigmentation but also various degrees of inflammatory change, such as hemosiderin-laden macrophages, gliosis and fibrosis. However, there is some controversy regarding the epileptogenic potential of these regions due to the uncertain nature of the mechanisms contributing to these histopathological changes.

METHODS

To investigate the correlations between neuron hyperexcitability and evident pathological changes, we performed ex vivo flavoprotein fluorescence imaging using surgically resected epileptogenic foci surrounding CA. The mirror surfaces of the tissues used for the physiological experiment were also subjected to morphological examination.

RESULTS

Hemosiderin-laden macrophages and many gemistocytic astrocytes were observed in the area adjacent to CA, where horizontal spreading excitations were detected significantly more frequently. Outside these areas, we found fine granular iron deposits and only a few fibrillary astrocytes, and weakly propagating excitations were detected. Furthermore, areas of enhanced activation were more clearly correlated with the glial proliferation index than with iron deposition.

CONCLUSION

These results suggest that the epileptogenesis in patients with CA may be based on a biological process, such as alteration of glial function, rather than direct chemical reactions involving iron deposition.

An international call for a new grading system for cerebral and cerebellar cavernomas

Surgical indications for cerebral cavernous malformations remain significantly center- and surgeon-dependent. Available grading systems are potentially limited, as they do not include epileptological and radiological data. A novel grading system is proposed for supratentorial and cerebellar cavernomas: it considers neuroradiological features (bleeding, increase in size), neurological status (focal deficits and seizures), location of the lesion and age of the patient. The score ranges from -1 to 10; furthermore, surgery should be considered when a score of 4 or higher is present. Based on neuroradiological characteristics, 0 points are assigned if the CCM is stable in size at different neuroradiological controls, 1 point if there is an increase in volume during follow-up, 2 points if intra- or extra-lesional bleeding <1 cm is present and 3 points if the CCM produced a hematoma >1 cm. Regarding focal neurological deficits, 0 points are assigned if absent and 2 points if present. For seizures, 0 points are assigned if absent, 1 point if present, but controlled by medications, and 2 points if drug resistant. We considered the site of the CCM, and in case of deep-seated lesions in a critical area (basal ganglia, thalamus) 1 point (-1) is subtracted, while for subcortical or deep cerebellar lesions 0 points are assigned, for CCMs in a cortical critical area 1 point is assigned and in case of lesions in cortical not in critical area or superficial cerebellar area, 2 points are assigned. As far as age is concerned, 0 points are assigned for patients older than 50 years and 1 point for patients younger than 50. In conclusion, a novel grading for surgical decision making in cerebral cavernomas, based on the experience of selected neurosurgeons, basic scientists, and patients, is suggested with the aim of further improving and standardizing the treatment of CCMs. The aim of this paper was also to call for both retrospective and prospective multicenter studies with the aim of testing the efficacy of the grading system in different centers.

Aeromedical Implications of Cerebral Cavernomas

BACKGROUND: Cavernomas, cavernous angiomas, or cerebral cavernous malformations are clusters of endothelium-lined blood vessels usually found in the brain. With the increasing use of radiological imaging, these are being detected incidentally in asymptomatic aircrew. The UK Civil Aviation Authority (CAA) experience of cavernomas is described and the aeromedical concerns, that is, the risk of epilepsy, hemorrhage, and the development of a neurological deficit, are considered.METHODS: A search of the CAA database between 1990 and 2020 was performed for the term cavernoma. The gender, age at diagnosis, class of certification held, clinical presentation, location, and size of the lesion were noted. A PubMed literature review for papers with complications of cavernoma was performed.RESULTS: Six cases of cavernoma have been declared to the CAA: five professional pilots and one private pilot. Five were men and one was a woman. The age range was between 38 and 60 yr, with a mean of 48 yr. Two cases presented with clinical symptoms and four were asymptomatic. Complication rates for seizure and hemorrhage were extracted from the published literature together with the significance of other factors such as cavernoma size, family history, multiplicity, and the development of new lesions.DISCUSSION: A policy for the medical certification of aircrew with cavernomas that have presented with clinical symptoms and those that are detected incidentally is proposed.Jagathesan T, OBrien M. Aeromedical implications of cerebral cavernomas. Aerosp Med Hum Perform. 2021; 92(2):120123.

Epilepsy Lesion Localization is not Predicted by Developmental Venous Anomaly Location or its FDG-PET Metabolic Activity

BACKGROUND AND PURPOSE

This study's purpose is to correlate location and metabolic activity of developmental venous anomalies (DVAs) in epilepsy patients to the seizure focus as determined by ictal/interictal encephaloelectrogram (EEG).

METHODS

A retrospective search was performed for epilepsy patients with DVAs who underwent brain ¹⁸ F-fluorodeoxyglucose positron emission tomography (¹⁸ F-FDG-PET) and magnetic resonance imaging (MRI). MRI exams were analyzed to characterize DVA location and associated structural findings. MRI and PET images were co-registered and assessment of ¹⁸ F-FDG uptake in the DVA territory was performed. The electronic medical record was reviewed for each subject to determine seizure semiology and site of seizure focus by ictal/interictal EEG.

RESULTS

Twenty-eight DVAs in 25 patients were included. Twelve DVAs demonstrated regional metabolic abnormality on ¹⁸ F-FDG-PET. There was no significant correlation between DVA site and seizure focus on EEG. DVA location was concordant with EEG seizure focus in three subjects, and all three demonstrated hypometabolism on ¹⁸ F-FDG-PET. This significance remains indeterminate, as one of these DVAs was associated with cavernoma, which could serve as the true seizure focus, and one of the patients underwent resection of the DVA without decrease in seizure frequency. Furthermore, there was no statistically significant relationship between DVA metabolic activity and DVA-EEG lobar or laterality concordance.

CONCLUSIONS

In this sample, there is no significant correlation between location of DVA and seizure focus, and hypometabolism within the DVA territory is not predictive of EEG/DVA co-localization. As use of ¹⁸ F-FDG-PET for evaluation of epilepsy increases, knowledge of this poor correlation is important to avoid diagnostic confusion and potentially unnecessary surgery in epilepsy patients.

Gamma Knife radiosurgery for cerebral cavernous malformation

This is a retrospective study examining the efficacy and safety of Gamma Knife radiosurgery (GKS) in treating patients with cerebral cavernous malformations (CCMs). Between 1993 and 2018, 261 patients with 331 symptomatic CCMs were treated by GKS. The median age was 39.9 years and females were predominant (54%). The median volume of CCMs was 3.1 mL. The median margin dose was 11.9 Gy treat to a median isodose level of 59%. Median clinical and imaging follow-up times were 69 and 61 months, respectively. After the initial hemorrhage that led to CCM diagnosis, 136 hemorrhages occurred in the period prior to GKS (annual incidence = 23.6%). After GKS, 15 symptomatic hemorrhages occurred within the first 2 years of follow-up (annual incidence = 3.22%), and 37 symptomatic hemorrhages occurred after the first 2 years of follow-up (annual incidence = 3.16%). Symptomatic radiation-induced complication was encountered in 8 patients (3.1%). Mortality related to GKS occurred in 1 patient (0.4%). In conclusion, GKS decreased the risk of hemorrhage in CCM patients presenting with symptomatic hemorrhage. GKS is a viable alternative treatment option for patients with surgically-inaccessible CCMs or significant medical comorbidities.

Supratentorial cavernoma and epilepsy: Experience with 23 cases and literature review

Background

The current study aimed to assess the role of microsurgical treatment of patients with supratentorial cavernoma with epilepsy based on analysis of our patients.

Methods

This retrospective study included 23 patients with supratentorial cavernoma on computed tomography (CT) scan and magnetic resonance imaging (MRI) of the brain admitted to the Department of Neurosurgery, Assiut University Hospitals (single tertiary hospital) between January 2014 and January 2018 (minimum 12-month follow-up). Deep-seated hemispheric and multiple cavernomas were excluded. Radiographs and hospital data of the patients were gathered and analyzed. All patients underwent the surgical procedure by one experienced neurosurgeon and the diagnosis was confirmed by pathologic evaluation.

Results

A total of 23 patients underwent surgical intervention consist of 15 (65%) men and 8 (35%) women. Their age varies from 11 to 59 year with an average of 36.6 years. All patients presented with seizure. The supratentorial cavernomas were located commonly in temporal lobes; 9 patients (39.1%). 19 (83%) of cavernoma located in the left side. 18 (78%) of cavernoma had a size <2 cavernoma. Complete excision was confirmed in postoperative investigations (CT and MRI brain images). All 10 patients with only one seizure preoperatively were seizure free at follow-up. Of nine patients who had experienced between two and five seizures preoperatively, 7 (78%) were seizure free, and of four patients with numerous seizures preoperatively, 3 (75%) were seizure free.

Conclusion

Our retrospective population study demonstrates an insight into the supratentorial cavernoma and suggests that microsurgical removal of the symptomatic cavernoma is generally accepted as the most effective and safe method.

Is additional mesial temporal resection necessary for intractable epilepsy with cavernous malformations in the temporal neocortex?

PURPOSE

Cavernous malformation (CM) in the temporal neocortex causes intractable epilepsy. Whether to resect additional mesial temporal structures in addition to the lesionectomy is a still controversial issue. To clarify the need for the procedure, we retrospectively analyzed pre- and postoperative clinical data of patients with surgically removed CM.

SUBJECTS AND METHODS

We included data from 18 patients with CM in the temporal neocortex who presented with intractable epilepsy. Eleven patients of our early series were treated with extended resection, i.e., lesionectomy and the resection of additional mesial temporal structures. Seven patients underwent lesionectomy, i.e., removal of the CM and of hemosiderin-stained surrounding brain tissue. Pathological assessments of the resected hippocampus were performed. Chronic intracranial electroencephalography (EEG) recordings were obtained in 6 patients. We performed perioperative neuropsychological assessments in all patients.

RESULTS

The seizure outcome was recorded as Engel class I in 17 patients (94.4%); Ia = 12 (66.7%) Ib = 2 (11.1%), Ic = 1 (5.6%), Id = 2 (11.1%), and class IIb in one patient (5.6%). Adding resection of the mesial temporal structures to lesionectomy did not alter the seizure outcome. Pathology of hippocampus revealed limited neuronal loss in CA4. Ictal onsets in the ipsilateral lateral cortex were detected in all 6 patients who underwent intracranial EEG. In 4 patients each, we also detected ictal onsets from the ipsilateral mesial temporal structures and from the contralateral temporal lobe. Postoperatively, in the patients where their CM was located in the language-dominant hemisphere (n = 10), the full-scale intelligence quotient (IQ) and the performance IQ increased (p < 0.05), whereas the verbal memory (WMS-R) deteriorated in two of 5 patients.

CONCLUSION

Excellent seizure outcomes were obtained even the lesionectomy alone. To confirm appropriate surgical strategy for lateral temporal CM with intractable epilepsy, further studies in large sample size are needed.

[Surgical treatment of epilepsy in patients with mediobasal temporal cavernous malformations]

OBJECTIVE

Epilepsy is a frequent clinical manifestation of cavernous malformations (CMs) of the mediobasal temporal region (MBTR). Surgical removal of CMs is an excellent technique for treating associated epilepsy and may range from pure lesionectomy to tailored resection of the temporal lobe.

PURPOSE

The study purpose was to determine the optimal surgical management for epilepsy in patients with CMs of the MBTR.

MATERIAL AND METHODS

We retrospectively analyzed the clinical data, neuroimaging findings, surgical techniques, and surgical outcomes in 11 patients with epilepsy and CMs of the MBTR. All patients underwent video-electroencephalography, magnetic resonance imaging, and computed tomography in the pre- and postoperative periods. Nine patients underwent preoperative implantation of foramen ovale electrodes. In all cases, surgery was accompanied by electrocorticography (ECoG).

RESULTS

CMs were located in the anterior MBTR in 7 cases, anterior and middle thirds of the MBTR in 1 case, middle third in 2 cases, and middle and posterior thirds in 1 case. In 8 patients, preoperative monitoring revealed a seizure onset area in the MBTR. These patients underwent cavernomectomy with ECoG-guided resection of the hemosiderin ring and adjacent tissue using the pterional (4 cases) or supracerebellar transtentorial approach (4). In 3 cases, anterior temporal lobectomy with cavernomectomy was additionally used due to spreading of pathological activity to the lateral temporal neocortex. Seizure control after surgery was excellent in 7 patients (class 1 ILAE) and good in 4 (class 2 ILAE).

CONCLUSION

Surgery in patients with epilepsy caused by CMs of the MBTR should be performed based on non-invasive and invasive presurgical evaluation. If the seizure onset area is located in the MBTR, lesionectomy with ECoG-guided resection of the adjacent temporal cortical areas can be performed using the pterional or supracerebellar transtentorial approach. Lateral spread of epileptic activity requires cavernomectomy and anterior temporal lobectomy.

Surgical Management and Long-Term Seizure Outcome After Surgery for Temporal Lobe Epilepsy Associated with Cerebral Cavernous Malformations

OBJECTIVE

Operative strategies for cerebral cavernous malformation (CCM)-associated temporal lobe epilepsy and timing of surgical intervention continue to be debated. This study aimed to establish an algorithm to evaluate the efficacy of surgical intervention strategies, to maximize positive surgical outcomes and minimize postsurgical neurologic deficits.

METHODS

47 patients having undergone operation for CCM-associated temporal lobe epilepsy were retrospectively reviewed. They had received a diagnostic series for seizure localization, including long-term video electroencephalography (vEEG), high-resolution magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT). In patients with mesial temporal lobe CCMs, the involved structures (amygdala, hippocampus, or parahippocampal gyrus) were resected in addition to the lesions. Patients with neocortical epileptogenic CCM underwent extended lesionectomy guided by intraoperative electrocorticography; further performance of amygdalohippocampectomy depended on the extent of hippocampal epileptogenicity.

RESULTS

The study cohort contained 28 patients with drug-resistant epilepsy (DRE), 12 with chronic epilepsy (CE), and 7 with sporadic seizure (SS). Normal temporal lobe metabolism was seen in 7/7 patients of the SS group. Hypometabolism was found in all patients with chronic disease except for those with posterior inferior and middle temporal gyrus cavernous malformations (CMs). Of the 31 patients with superficial neocortical CCM, 7 had normal PET without hippocampal sclerosis, 14 had ipsilateral temporal lobe hypometabolism without hippocampal sclerosis, and 10 had obvious hippocampal sclerosis and hypometabolism. Seizure freedom in DRE, CE, and SS was 82.1%, 75%, and 100%, respectively. A significant difference was found between lesion laterality and postoperative seizure control; the rate was lower in left-sided cases because of less aggressive resection.

CONCLUSIONS

Our study demonstrates that the data from the presurgical evaluation, particularly regarding CM location, responsiveness to antiepileptic drugs, and temporal lobe metabolism, are crucial parameters for choosing surgical approaches to CCM-associated temporal lobe epilepsy. By this operative strategy, patients may receive maximized seizure control and minimized postsurgical neurologic sequelae.

Outcome after conservative management or surgical treatment for new-onset epilepsy in cerebral cavernous malformation

OBJECTIVE

The aim of this study was to determine seizure outcome, functional outcome, and the withdrawal of antiepileptic drugs (AEDs) after conservative or surgical treatment of patients with new-onset cavernoma-related epilepsy (CRE).

METHODS

The authors conducted a retrospective comparative observational study of 79 consecutive patients, each with a single sporadic cerebral cavernous malformation (CCM) and new-onset CRE.

RESULTS

Forty-one patients underwent initial surgery (IS), and 38 patients underwent initial conservative (IC) treatment. Of those in the latter group, 19 underwent delayed surgical (DS) treatment. At the last follow-up, 88%, 32%, and 79% of patients in the respective groups had been seizure free for at least 2 years (International League Against Epilepsy [ILAE] Class 1; IS vs IC, p < 0.0001) and 78%, 8%, and 58%, respectively, had been off AEDs (IS vs IC, p < 0.0001). The cumulative probability of staying seizure free (ILAE Class 1) during a 5-year period was 73% (mean seizure-free follow-up 49.8 ± 2.7 months, 95% CI 44.4–55.1 months) for the IS group, 22% (mean 31.8 ± 3.6 months, 95% CI 24.8–38.8 months) for the IC group, and 68% (mean 48.6 ± 4.3 months, 95% CI 40.1–57.1 months) for the DS group (IS vs IC p < 0.001). Long-term operative morbidity was 3%, and long-term morbidity in the conservatively treated group was also 3%.

CONCLUSIONS

Patients with CCM and new-onset CRE who underwent IS treatment showed better results in seizure control and the discontinuation of AEDs than the conservatively treated patients. Operative morbidity was comparable to the morbidity from symptomatic CCM hemorrhage in the conservative group. Half of the patients who started with conservative treatment underwent subsequent surgical treatment; however, a longer duration of epilepsy prior to surgery did not worsen postoperative seizure outcome.

Pathology of cavernous malformations

Cavernous malformations (CMs) are low-pressure angiographically occult lesions, composed of blood-filled sinusoidal locules known as "caverns." Although these lesions were once believed to be congenital in nature, there is compelling evidence to support de novo formation of CMs as well. They can occur as sporadic lesions or be inherited in an autosomal-dominant phenotype in familial forms of the disease. The pathophysiology of CMs is commonly believed to be due to abnormal vascular pathology. Three genes, CCM1, CCM2, and CCM3, have been extensively studied for their role in vascular pathology, resulting in abnormal angiogenesis and compromising the structural integrity of vessel endothelial cell. The expression of growth factors has been researched to gain insight into the dynamic behavior of CM lesions. Gross and microscopic images are utilized in this chapter to illustrate the pathologic findings of these lesions. Ultrastructural analysis demonstrates the aberrations in CM endothelial cells and structural integrity that may provide better understanding into how and why these lesions have a propensity to hemorrhage.

Temporal lobe epilepsy and cavernous malformations: surgical strategies and long-term outcomes

OBJECTIVE

Cerebral cavernous malformations (CCM) of the temporal lobe often present with seizures. Surgical resection of these lesions can offer durable seizure control. There is, however, no universally accepted methodology for assessing and surgically treating these patients. We propose an algorithm to maximize positive surgical outcomes (seizure control) while minimizing post-surgical neurological deficit.

METHODS

A retrospective review of 34 patients who underwent epilepsy surgery for radiographically proven temporal lobe CCM was conducted. Patients underwent a relatively standard work-up for seizure localization. In patients with mesial temporal lobe epilepsy (MTLE), a complete resection of the epileptogenic zone was performed including amygdalo-hippocampectomy in addition to a lesionectomy if not contraindicated by pre-operative work-up. Patients with neocortical epilepsy underwent intraoperative electrocorticography (ECoG)-guided lesionectomy.

RESULTS

Seizure-free rate for mesial and neocortical (anterior, lateral, and basal) location was 90 vs. 83 %, respectively. Complete resection of the lesion, irrespective of location, was statistically significant for seizure control (p = 0.018). There was no difference in seizure control based on disease duration or location (p > 0.05). Patients with mesial temporal CCM who presented with MTLE were presumed to also have mesial temporal sclerosis (MTS), or dual pathology. These patients underwent routine resection of the mesial structures. Interestingly, patients who had MTLE and basal (neocortical) lesions who underwent a mesial resection for suspected MTS were found not to have dual pathology.

CONCLUSIONS

Patients with temporal lobe CCM should be offered resection for durable seizure control, prevention of secondary epileptogenic foci, and elimination of hemorrhage risk. The preoperative work-up should follow a team approach. Surgical intervention should include complete lesionectomy in all cases. Intra or extra-operative ECoG for neocortical lesions may be beneficial. Management of mesial temporal CCMs (archicortex) should consider resection of a well-defined epileptogenic zone (including mesial structures) due to high probability of pathologically proven MTS. The use of this treatment algorithm is useful for the education and treatment of these patients.

Treatment and outcome of epileptogenic temporal cavernous malformations

Background:

The aim of this study is to explore the treatment and outcome of epileptogenic temporal lobe cavernous malformations (CMs).

Methods:

We analyzed retrospectively the profiles of 52 patients diagnosed as temporal lobe CMs associated with epilepsy. Among the 52 cases, 11 underwent a direct resection of CM along with the adjacent zone of hemosiderin rim without electrocorticogram (ECoG) monitoring while the other 41 cases had operations under the guidance of ECoG. Forty-six patients were treated by lesionectomy + hemosiderin rim while the other six were treated by lesionectomy + hemosiderin rim along with extended epileptogenic zone resection. The locations of lesions, the duration of illness, the manifestation, the excision ranges and the outcomes of postoperative follow-up were analyzed, respectively.

Results:

All of the 52 patients were treated by microsurgery. There was no neurological deficit through the long-term follow-up. Outcomes of seizure control are as follows: 42 patients (80.8%) belong to Engel Class I, 5 patients (9.6%) belong to Engel Class II, 3 patients (5.8%) belong to Engel Class III and 2 patients (3.8%) belong to Engel Class IV.

Conclusion:

Patients with epilepsy caused by temporal CMs should be treated as early as possible. Resection of the lesion and the surrounding hemosiderin zone is necessary. Moreover, an extended excision of epileptogenic cortex or cerebral lobes is needed to achieve a better prognosis if the ECoG indicates the existence of an extra epilepsy onset origin outside the lesion itself.

State of the Art Approach to the Classification of Epileptic Seizures and Epilepsies

In the light of the latest knowledge acquired from clinical and laboratory research dealing with genetic, molecular biology and neuroimaging, existing classifications were successively revised by the International League Against Epilepsy (ILAE) in 2001, 2006, and 2010. In the latest classification established in 2010, proposals articulated radical changes in terms of concepts and definitions of the previously published classifications and put forward new classifications for epileptic seizures, epilepsies and electroclinical syndromes. This review refers to the changes of the new classification with their reasons and criticisms.

Cerebral cavernous malformations in the setting of focal epilepsies: pathological findings, clinical characteristics, and surgical treatment principles

Cavernous cerebral malformations (CCMs) are a well-defined epilepsy-associated pathology. They represent lesions/conglomerates of abnormally configured vessels leading to seizures either as a result of physiological changes affecting the cerebral cortex immediately surrounding the CCM (an epileptogenic mechanism that is relevant for both temporal and extratemporal lesions), or as a result of promoting epileptogenicity in remote but anatomo-functionally connected brain regions (a mechanism that is particularly relevant for temporal lobe lesions). This review details the pathological findings in CCMs and discusses the mechanisms of epileptogenicity in this context. The bulk of the review will focus on therapeutic strategies. Medical therapy using antiepileptic drugs is recommended as a first-line therapy, but surgical removal of the CCM with the surrounding cortex should be pursued if seizures prove to be drug resistant. Early timing of the resection and complete removal of any associated epileptic pathology are critical for best outcomes. In addition to reviewing the available data from prior series, we present original research from two specialized epilepsy centers targeted at answering particularly pressing clinical questions mainly related to the ideal timing and extent of surgery. Further research is needed to define the best surgical strategies in patients with temporal lobe CCMs and structurally normal hippocampi.

Surgical Resection Can Be Successful in a Large Fraction of Patients With Drug-Resistant Epilepsy Associated With Multiple Cerebral Cavernous Malformations

BACKGROUND:

Multiple cerebral cavernous malformations (mCCMs) are known as potentially epileptogenic lesions. Treatment might be multimodal. Management of patients with mCCMs and epilepsy is challenging.

OBJECTIVE:

To evaluate (1) algorhythmic therapeutic sequences in patients with epilepsy associated to mCCMs, (2) whether there are predictive parameters to anticipate the development of drug-resistant epilepsy, and (3) seizure after epilepsy surgery compared to conservatively-treated drug-resistant patients.

METHODS:

All inpatients and outpatients with epilepsy associated to mCCMs from 1990 to 2010 and follow-up &gt;12 months available were retrospectively analyzed.

RESULTS:

Twenty-three patients matched inclusion criteria. Epilepsy became drug-resistant in 18/23 (78%) patients. No predictors were found for development of drug-resistant epilepsy. Median follow-up for both groups was 7.8 years. Nine patients did not qualify for surgical therapy and were treated conservatively. One patient of this cohort (11%) was seizure-free (International League Against Epilepsy [ILAE] class 1). Surgical treatment was performed in 9 patients; 7/9 (78%) of these patients were seizure-free (ILAE class 1) after epilepsy surgery for at least 12 months compared with 1/9 patients in the non-operated group. In 7/9 cases (78%) the largest CCM was resected. In 8/9 (89%) not all CCMs were resected.

CONCLUSION:

After initial diagnosis of epilepsy associated to mCCMs, a primary conservative approach is reasonable. Surgical treatment can be successful in a large fraction of cases with drug-resistant epilepsy where an epileptogenic lesion is identified. Cases where surgery is not undertaken are likely to remain intractable.

The outlook for adults with epileptic seizure(s) associated with cerebral cavernous malformations or arteriovenous malformations

Cerebral cavernous malformations (CCMs) and arteriovenous malformations (AVMs) are common: their asymptomatic prevalence on brain magnetic resonance imaging (MRI) is 1 in 625 and 1 in 2,000, respectively. The risk of epileptic seizure(s) for people with AVMs and CCMs affects their domestic, social, and professional lives, and may influence their decisions about treatment. This article summarizes the seizure risks for people with AVMs and CCMs, gleaned from published original articles indexed in OVID Medline and Embase before 1 January 2012. In the absence of prior intracranial hemorrhage and nonhemorrhagic focal neurologic deficit, a population-based study in Scotland, United Kingdom, found that the 5-year risks of first seizure were 8% for AVM and 4% for CCM; presentation with intracranial hemorrhage or focal neurologic deficit raised this risk for AVM (23%) but not for CCM (6%). Features associated with the occurrence of epileptic seizures for CCM are lesion multiplicity and cortical CCM location, whereas for AVM the most consistently reported associations are younger age, temporal location, cortical involvement, and nidus diameter >3 cm. In the absence of prior intracranial hemorrhage and nonhemorrhagic focal neurologic deficit, the 5-year risk of developing epilepsy following a first seizure is 58% for AVM and 94% for CCM, though there is no difference in the chance of achieving 2-year seizure freedom in this time frame (45% AVM vs. 47% CCM). Observational case series describe encouraging differences in seizure frequency before and after AVM and CCM treatment, but the shortage of studies demonstrating dramatic effects in comparison to concurrent control groups justifies the need for more controlled studies, ideally with randomized treatment allocation when the benefits of AVM or CCM treatment are uncertain.

Surgical treatment of symptomatic cerebral cavernous malformations in eloquent brain regions

BACKGROUND

Despite the increased risk of hemorrhage and deteriorating neurological function of once-bled cerebral cavernous malformations (CM), the management of eloquently located CMs remains controversial.

METHODS

All eloquently located CMs (n = 45) surgically treated between 03/2006 and 04/2011 in our department were consecutively evaluated. Eloquence was characterized according to Spetzler and Martin's definition. The following locations were approached: brainstem, n = 16; sensorimotor, n = 8; visual pathway, n = 7; cerebellum (deep nuclei and peduncles), n = 7; basal ganglia, n = 4, and language, n = 3. Follow-up data was available for 41 patients (91 %) with a median interval of 14 months. Outcomes were evaluated according to the Glasgow outcome and the modified Rankin scale.

RESULTS

Immediately after surgery, 47 % (n = 21) had a new deficit. At follow-up, 80 % (n = 36) recovered to at least preoperative status or were better than before surgery, 9 % (n = 4) exhibited a slight, and 7 % (n = 3) had a moderate neurological impairment. Only two cases (4 %) with a new permanent severe deficit were observed, both related to dorsal brainstem surgery. The outcome after the surgery of otherwise located brainstem CMs was as beneficial as that for non-brainstem CMs. Patients with initially poor neurological performance fared worse than oligosymptomatic patients.

CONCLUSIONS

Despite the high postoperative transient morbidity, the majority improved profoundly during follow-ups. Compared with natural history, surgical treatment should be considered for all eloquent symptomatic CMs. Dorsal brainstem location and poor preoperative neurological status are associated with an increased postoperative morbidity.

Surgical management of cavernous malformations presenting with drug-resistant epilepsy

Cerebral cavernous malformations (CMs) are dynamic lesions characterized by continuous size changes and repeated bleeding. When involving cortical tissue, CMs pose a significant risk for the development of drug-resistant epilepsy, which is thought to be result of an altered neuronal network caused by the lesion itself and its blood degradation products. Preoperative evaluation should comprise a complete seizure history, neurological examination, epilepsy-oriented MRI, EEG, video-EEG, completed with SPECT, PET, functional MRI, and/or invasive monitoring as needed. Radiosurgery shows variable rates of seizure freedom and a high incidence of complications, thus microsurgical resection remains the optimal treatment for CMs presenting with drug-resistant epilepsy. Two thirds of patients reach Engel I class at 3-year follow-up, regardless of lobar location. Those with secondarily generalized seizures, a higher seizure frequency, and generalized abnormalities on preoperative or postoperative EEG, show poorer outcomes, while factors such as gender, duration of epilepsy, lesion size, age, bleeding at the time of surgery, do not correlate consistently with seizure outcome. Electrocorticography and a meticulous removal of all cortical hemosiderin - beyond pure lesionectomy - reduce the risk of symptomatic recurrences.

A gut feeling about insular seizures

A 43-year-old man presented to the Prince of Wales Hospital, Sydney, New South Wales, Australia, after experiencing his first tonic-clonic seizure. For the previous 2 years he had undergone gastroenterological investigation of episodes of gagging associated with hypersalivation and lachrymation, occurring three or four times per week. EEG showed epileptiform discharges in the right anterior temporal region; brain MRI revealed a lesion in the right insular cortex. Video-EEG telemetry demonstrated that the episodes of gagging were focal seizures. Antiepileptic drug therapy resulted in no further episodes occurring over the next 10 months.

Epidermoid cyst involving the medial temporal lobe: surgical pathologic features of the epileptogenic lesion

Epidermoid cysts in the middle fossa are rare and may involve the temporal lobe and lateral ventricle. Affected patients often suffer from seizures, but the pathomechanisms underlying the epileptogenic lesions have remained unclear. Here we report the surgical pathological features of the hippocampus in a 31-year-old woman with mesial temporal lobe epilepsy (mTLE), in whom an epidermoid cyst involving the right basal cistern and inferior horn of the lateral ventricle was evident. The ictal electrocorticogram indicated seizure onset at the parahippocampal gyrus. An anterior temporal lobectomy and amygdalohippocampectomy were performed. Histologically, the hippocampus showed marked atrophy with severe loss of pyramidal neurons in the cornu Ammonis subfields and granule cell loss in the dentate gyrus. At the ventricular surface of the hippocampus, there were small granulomatous lesions with spicularly anchored keratin substance. These features indicated multiple and chronic stab wounds by the cyst contents and consequent local inflammatory responses within the parenchyma. The predisposition to adhesion between the tumor and hippocampus may have caused neurons to develop abnormal irritability to certain chemical mediators present in the cyst. Epileptogenicity involving the atrophic hippocampus and medial temporal lobes nearby may have developed in association with these processes. This case appears to provide information that is useful for surgical planning in patients with mTLE and epidermoid cysts involving the medial temporal lobe.

Cerebral cavernous malformations and intractable epilepsy: the limited usefulness of current literature

BACKGROUND

Cerebral cavernous malformations (CCM) are known to be highly epileptogenic lesions. A number of studies on CCM surgery deal with CCM-associated seizures and/or epilepsy. In order to counsel patients with CCM-associated epilepsy, clear results from such studies would be highly useful. This study reviews the current literature with the aim to assess its usefulness for presurgical decision-making with emphasis on differentiating outcomes in different epilepsy types.

METHODS

A systematic Medline search identified 27 studies between 1991 and 2009 through the keywords "cavernomas, cavernous, hemangioma, AND epilepsy, AND surgery". They were analysed with regard to clarity of definition of epilepsy subtypes, precision of definition of drug-resistant epilepsy, information on surgical procedure and presurgical workup, seizure outcome and length of follow-up.

RESULTS

Twenty studies included only surgically treated patients. Three types of epilepsy were defined: drug-resistant epilepsy, epilepsy or single/sporadic seizures. In 12 of 27 studies, at least one of these categories remained unclear. The classic definition of drug-resistant epilepsy was not used in the vast majority of studies, with many groups using their own definition. In 30%, the surgical procedure was not described precisely, although 52% of studies used a differentiated preoperative evaluation. Seizure outcome was described using a widely accepted classification in only 48% of series, and in over half of the studies outcome results contained cases with insufficient length of follow-up.

CONCLUSIONS

A large proportion of recent studies on surgery for CCM-associated epilepsy are not using criteria and definitions for the classification of epilepsy and outcome that are commonly used by epileptologists or epilepsy surgeons. This results in the limited usefulness of a large part of the literature for the purpose of preoperative counselling a patient with CCM-associated epilepsy.