[Comparative characteristics of genetic aberrations in glioblastomas in children and adults].

Glioblastomas in children and adults are a heterogeneous group of tumors that can be divided into at least three different subgroups: pediatric glioblastomas, IDH1-mutant glioblastomas in adults (the most favorable prognostic subtype), and IDH1-wild type glioblastomas in adults. According to the frequency of detected cytogenetic aberrations (amplification of the MYC/MYCN, EGFR and PDGRFA oncogenes, homozygous deletion of the CDKN2A gene, and deletion of the PTEN gene), pediatric glioblastomas bear analogy to the subgroup of IDH1-mutant glioblastomas in adults.

[Meningiomas: anatomical pathology and molecular biology].

In the past 5-10 years, there has been a considerable progress the understanding of the biology of meningioma. The most important advances have been made by comprehensive studies of the pathogenesis of meningioma in molecular genetics. Several target genes could be identified for mutation or inactivation. Additional chromosomal regions that are usually subject to deletion or amplification and point to the presence of tumor suppressor genes or proto-oncogenes were found. The revised and updated 2000 WHO Classification is a major innovation in the histopathology of meningiomas. The new classification system more precisely and objectively determines the grade of meningioma, which allows one to more logically make a prognosis of the recurrence and aggressive behavior of the tumor. The present overview places particular emphasis on recent advances in its molecular biology. It summarizes the most important aspects of the classification of meningiomas, which makes it possible to include the results of biological observations into the respective context, and also considers the mechanisms of angiogenesis and edema development and the role of hormonal receptors in meningiomas.

[Cytogenetic aberrations in histologically benign infiltratively growing sphenoid wing meningiomas].

Meningiomas of the sphenoid wing (SW) frequently show an invasive pattern of growth and cause destruction of the adjacent structures. As a result, the rate of recurrent SW meningiomas is as high as 30%. Cytogenetic investigations showed no aberrations specific to invasively growing meningiomas. During this study, the authors evaluated 10 invasive and 5 non-invasive SW meningiomas via comparative genome hybridization (CGH) (matrix CGH), by using the gene chips of GenoSensor Array micromatrixes. The mean number of aberrations in the tumor cells was much greater in case of invasive meningiomas (67.4 versus 40.5 in case of non-invasive SW meningiomas. Furthermore, in invasive SW meningiomas, there were frequently losses in loci 1p, 6q, and 14q and gains in loci 15q and 10, which had been predetermined as molecular markers of stepwise progression of meningioma. Thus, the presence of a complex cytogenetic profile and progression-associated chromosome aberrations in benign SW meningiomas is linked with the increase of their invasive potential. Due to the fact that there are no well-defined adjuvant therapy regimens for recurring meningiomas at present, the revealed genomic aberrations may become potential targets for searching for drugs and a therapeutic intervention in future.

[Experience in using a molecular resonance coagulator in neurooncology].

The paper analyzes the experience gained in using a molecular resonance coagulator in 145 patients with tumors of the base of the skull and brain. The Vesalius NEUROsurgery N1 molecular resonance apparatus is an innovational bipolar device that is specially designed for neurosurgical application,(operations on the brain). Due to the fact that the temperature at the site of a cut does not exceed 45-50 degrees C, the apparatus has the minimum effect on tissues, nerves, nerve ending, and blood vessels, permitting a surgeon to make interventions into sophisticated anatomic formations. The apparatus operates in the modes "cut" and "coagulation" that enable operations to be performed on particularly minor and fine structures. While working on brain tissues, it is particularly important that there is no thermal injury, tissue charring, or sticking effect due to low working temperatures. The possibility of concurrently making hemostasis and tissue dissection reduces the time of an operation and considerably decreases the extent of blood loss. The clinical case given in this paper demonstrates the universality of the Vesalius NEUROsurgery N1 molecular resonance apparatus used in an infiltrative tumor of the bases of the skull. One forceps operated in different modes may provide sparing coagulation of minor cortical arteries, reduce the volume of a tumor through its bloodless dissection, arrest bleeding from the hyperostosis (wax sticking effect), prepare nerves in the upper lid slit and cavernous sinus. The Vesalius NEUROsurgery N1 molecular resonance surgical apparatus is recommended for neurosurgical care to perform brain operations requiring great caution in handling the tissues being operated on.

[Skull base meningiomas spreading into the infratemporal fossa: clinical picture, diagnosis, and treatment policy]. / Meningiomy osnovaniia cherepa, rasprostraniaiushchiecia v podvisochnuiu iamku: klinika, diagnostika, taktika lecheniia.

From 1997 to 2004, the Academician N. N. Burdenko Research Institute of Neurosurgery has operated on 54 patients with intracranial meningiomas spreading into the infratemporal fossa. Fifteen patients were operated on for the first time. Thirty-nine patients had undergone surgical interventions on the average 3 times (from 2 to 8). All the patients were operated on via different orbitozygomatic approaches depending on the extent of the process. Opening the upper and lower palpebral fissures and the round foramen with resection, if required, the pterygoid processes suffice to remove tumors from the areas of the upper and lower palpebral fissures, which spread into the sphenoid and maxillary sinuses. If there are tumors at the site of the base of the anterior surface of the pyramid, and the articular bursa, it is expedient to open the oval and spinous foramens, to resect the external portions of the fundus of the middle cranial fossa and, if required, the articular process of the lower jaw. By taking into account the X-ray and histological patterns, it may be stated that invasion of meningiomas is not always accompanied by the development of hyperostosis. According to our findings, extracranial growth of meningiomas points to the invasion of osseous structures of the middle cranial fossa. Furthermore, if meningiomas grow into the infratemporal fossa, they frequently involve the muscles, nerves, and mucosa. After removing the tumors spreading to the infratemporal fossa, the optimum plastic repairs of defects of the base of the skull are as follows: hermetic closure of basal defect of the dura mater with a free fat flap, by fixing it with sutures and fibrin-thrombin glue with additional plastic repair of skull base defect with local displaced tissues on a pedicle (with a temporal muscular fascioperiosteal flap, a Bisch fat flap). Further policy of management of these patients is a complicated problem. It depends on the radicalism of an operation and the invasiveness of the process. The histobiological features of infiltrative meningiomas should be studied and this will determine management policy. Conceivably, the use of postoperative radiation therapy will be substantiated in a definite group of patients.

[A broad subfrontal access to the tumors in the base of the skull]. / Rasshirennyi subfrontal'nyi dostup k opukholiam osnovaniia cherepa.

A total of 30 patients, aged 16 to 67, with neoplasms in the brain base and in paranasal sinuses were operated on, during 1997-2002, at Burdenko's Research Institute for Neurosurgery of the Russian Academy of Medical Sciences (RAMS). A majority of patients (21) had meningiomas. Other observations included: fibrous dysplasia of the anterior cranial fossa in 3 patients, chondroma in 2 patients, angiofibroma in 2 patients, pituitary adenoma in 1 patient and adamantinoma in 1 patient. The application of diluted subfrontal approach and of its modifications is indicated for extradural tumors located in the anterior cranial fossa and extending into the latticed main sinus of the nasopharynx. No increasing neurological symptomatology was noticed in any patients. Nasal liquor was not noted either. A seizure of an essential reduction of exophthalmos was registered in cases with crania-orbital neoplasm. It restored postoperatively in all patients with malfunctions of nasal breathing. Two patients died. The death reasons are not directly related with the approach technique. The diluted subfrontal approach is effective in extensive tumors of the anterior cranial fossa involving the latticed and main sinuses. Our experience of using the diluted subfrontal approach showed its efficiency not only in extensive extradural neoplasms but also in large meningiomas of the anterior cranial fossa extending into the latticed sinus, main bone platform, tubercle of sella turcica and into both optic canals. The discussed approach ensures essentially reduced brain traction as compared with the traditional subfrontal approach. The hermetic closure of defects formed in the brain basis is an important surgery stage involving the diluted subfrontal approach. This approach is, under modern conditions, a valuable addition to the methods, which are generally accepted in neurosurgery, and it has undoubtedly an indisputable perspective.

[Access to the anterior cranial fossa through the frontal sinus]. / Dostup k opukholiam perednei cherepnoi iamki cherez lobnuiu pazukhu.

In 1998 to 2001, the Academician N. N. Burdenko Research Institute of Neurosurgery operated on 15 patients aged 20 to 65 years who had bulky processes in the base of the skull and paranasal sinuses by applying an access through the frontal sinus. Most patients (n = 7) had meningiomas. The others had osteoma of the base of anterior cranial fossa (n = 2), chondroma (n = 2), angiofibroma (n = 1), fibroma (n = 1), esthesioneuroepithelioma (n = 1), and neurinoma (n = 1). The main criteria for choosing this access were the site and extent of a process, the sizes of the frontal sinus, and no signs of acute or chronic rhinosinusitis. The length of frontal sinuses in the most measurement was 3.5 to 5.0 cm, their width was 7 to 10 cm. All patients showed no progression of neurological symptoms. Three patients had a decrease in visual acuity from 1.0 to 0.8; with vascular therapy, visual disorders regressed during 2 months. Olfaction became worse in 4 cases, there was anosmia in 2 cases. Nasal liquorrhea was not observed. When there were tumors in the anterior cranial fossa, an access through the anterior wall of the frontal sinus permits radical removal of both intra- and extracranial parts of a tumor with closure of the defect with a periostal flap.