[Long-term epilepsy-associated tumors]. / Glioneironal'nye opukholi, assotsiirovannye s epilepsiei.

OBJECTIVE: The goal of this review is to summarize data concerning radiological and histological diagnosis of epileptogenic tumors, as well as to discuss their surgical treatment. MATERIAL AND METHODS: PubMed literature database was searched for relevant articles, we also used our own clinical experience. RESULTS: Benign glioneuronal tumors are the second most common cause of drug resistant epilepsy in adults after hippocampal sclerosis. Exceptionally slow growth (more than 2 years), localization in the brain cortex, presence of differentiated neuronal tissue in tumoral body and long history of epilepsy are the key features of these tumors called LEAT (long-term epilepsy-associated tumors). Management of LEAT requires epileptological as well as neurooncological approach. The epileptogenic zone commonly spreads beyond the tumor borders and simple lesionectomy alone may not be sufficient for achieving seizure freedom. CONCLUSION: LEAT typically exhibit low proliferative activity, however they should be thoroughly differentiated from more aggressive glial tumors; while this task is sometimes quite challenging, it's achievable by means of histological and immunohistochemical examination.

Ictal and interictal MEG in pediatric patients with tuberous sclerosis and drug resistant epilepsy.

PURPOSE: Drug resistant epilepsy (DRE) is common in patients with tuberous sclerosis (TS). Interictal MEG has been shown as a valuable instrument in the presurgical workup. The goal of our study was to evaluate the role of ictal MEG in epileptogenic tuber selection, especially in patients with multiple irritative zones. METHODS: The clinical and MEG data of 23 patients with TS and DRE from two medical/research centers were reviewed. Seven pediatric patients, who had seizures during MEG recording and underwent resection or disconnection surgery, were included into the study. Cortical sources of ictal and interictal epileptiform MEG discharges were compared with epileptogenic zone location in six patients with favorable surgery outcome. RESULTS: In patients who improved substantially after surgery all resected and several other tubers demonstrated epileptiform activity on interictal MEG. Ictal MEG provided crucial information about lobar location of the seizure onset zone (SOZ) in two cases, and in the other four it confirmed the SOZ location derived from the interictal data. In one case, ictal MEG findings were unreliable. In one patient, who did not benefit from surgical treatment, the resected tubers did not overlap with interictal and ictal MEG sources. CONCLUSION: The combination of interictal and ictal MEG is a valuable tool for identification of the epileptogenic tuber/tubers in presurgical work-up in patients with TS.

[Hemispherectomy in the treatment of pediatric symptomatic epilepsy of children]. / Gemisferektomiya v lechenii simptomaticheskoi epilepsii u detei.

INTRODUCTION AND PURPOSE: Hemispherectomy is a recognized option in the treatment of symptomatic forms of intractable focal epilepsy in patients with developmental brain malformations and some acquired lesions of one the hemispheres. The prognosis for an outcome of the technique is important in terms of the indications for surgical treatment. MATERIAL AND METHODS: We described the hemispherectomy technique and its variants and analyzed our own experience of surgery in 40 children. The most common (27 cases) brain pathology was extended unilateral cortical dysplasia with polymicro- or pachygyria and consequences of perinatal stroke. Six children had Rasmussen encephalitis; 6 patients had hemimegalencephaly; 1 child with Sturge-Weber syndrome had angiomatosis of the soft meninges. The patients' mean age was 3 years. Functional hemispherectomy (hemispherotomy) was used in most cases (37); 3 patients underwent anatomical hemispherectomy. RESULTS: At the time of discharge, seizures resolved in all patients; later, no seizure recurrence was observed in 25 out of 29 cases with known follow-up (the follow-up median was 2.5 years), which corresponded to class 1 outcomes on the ILAE scale (86%). Serious complications developed in 2 cases; 1 patient died; hydrocephalus and the need for bypass surgery occurred in other 2 children. These results are discussed along with the literature data, and the indications for hemispherectomy are provided. CONCLUSION: Hemispherectomy is a reliable and effective technique for treatment of symptomatic hemispheric forms of epilepsy in children. More than in 80% of patients with congenital or acquired pathology of one of the cerebral hemispheres, its deafferentation or resection leads to persistent elimination of seizures. Children with severe forms of intractable epilepsy should be promptly referred to dedicated centers to address the issue of advisability of surgical treatment.

[Hippocampal sclerosis: pathogenesis, clinical features, diagnosis, and treatment]. / Skleroz gippokampa: patogenez, klinika, diagnostika, lechenie.

Hippocampal sclerosis, also known as Ammon horn sclerosis or mesial temporal sclerosis, is usually associated with intractable epilepsy and characterized by specific patterns of neuronal loss and gliosis in the medial temporal lobe structures. Hippocampal sclerosis manifests clinically as epilepsy, often intractable epilepsy; in most cases, this condition is surgically treatable. As the most common histological diagnosis in adult patients subjected to epilepsy surgery, hippocampal sclerosis is characterized by complex pathogenesis and requires a multidisciplinary approach to its diagnosis and treatment. This article reviews the pathologic features, natural history, pathogenesis, and electroclinical and MRI signs of hippocampal sclerosis.

[Supracerebellar transtentorial approach to tumors of the posterior portions of the medial temporal region].

OBJECTIVE: Despite the advances in microsurgery, the choice of the most adequate approach to the posterior part of the medial temporal region (MTR) remains a very controversial issue. The supracerebellar transtentorial approach (STA) is considered as the most preferable one, since it provides the optimal balance between retraction, incision, and resection of the brain tissue. Here, we present our consecutive series of 20 patients who underwent STA surgery. MATERIAL AND METHODS: Twenty patients with glial tumors affecting the posterior MTR underwent STA surgery between 2006 and 2014. The mean age of the patients was 20 years. Benign tumors were predominant (18 out of 20 cases). RESULTS: Resection of the posterior and middle MTRs was conducted in 16 cases. The anterior MTR was accessed through STA in 1 patient only; in 2 patients, STA was combined with the infraoccipital approach. Cerebellar edema occurred in 4 patients, with hemiparesis persisting in one of the cases for 1 year after surgery. Of 8 patients with drug resistant epilepsy, the Engel class 1 or 2 outcome was achieved in 6 cases within 1 year after surgery. CONCLUSION: STA provides an excellent surgical route to the posterior and middle MTR portions; however, the anterior MTR portions cannot be reached safely. The operative risks of STA increase as the surgeon proceeds with resection of the anterior MTR portions. Anterior MTR structures can be removed using a combination of the supracerebellar and infraoccipital transtentorial approaches or two-stage resection.

[Magnetoencephalography in the presurgical evaluation of patients with drug-resistant epilepsy].

Magnetoencephalography (MEG) in combination with structural MRI (magnetic source imaging, MSI) plays an increasingly important role as one of the tools for presurgical evaluation of medically intractable focal epilepsy. The aim of the study was to compare the MSI and commonly used video EEG monitoring method (vEEG) in their sensitivity to interictal epileptic discharges (IED) in 22 patients with drug resistant epilepsy. Furthermore, the detection and localization results obtained by both methods were verified using the data of electrocorticography (ECoG) and postsurgical outcome in 13 patients who underwent invasive EEG monitoring and surgery. The results showed that MSI was superior to vEEC in terms of sensitivity to IED with difference in sensitivity of 22%. The data also suggested that MSI superiority to vEEG in detecting epileptic discharges might, at least partly, arise from better MEG responsiveness to epileptic events coming from the medial, opercular and basal aspects of cortical lobes. MSI localization estimates were in the same cortical lobe and at the same lobar aspects as the epileptic foci detected by ECoG in all patients. Thus, magnetic source imaging can provide critical localization information that is not available when other noninvasive methods, such as vEEG and MRI, are used.