[Primary tumors of the brain stem. State of the problem]

Primary brainstem gliomas are still poorly studied in neurooncology. This concept includes tumors with different histological and genetic features, as well as variable clinical course and outcomes. Nevertheless, treatment implies radiotherapy without a clear idea of morphological substrate of disease in 80% of cases. Small number of studies and insufficient data on histological and genetic nature of brainstem tumors complicate clear diagnostic and treatment algorithms. This review provides current information regarding primary glial brainstem tumors. Appropriate problems and objectives are highlighted. The purpose of the review is to provide a comprehensive and updated understanding of the current state of brainstem glial tumors and to identify areas requiring further study for improvement of diagnosis and treatment of these diseases. Brainstem tumors are an understudied problem with small amount of data that complicates optimal treatment strategies. Further researches and histological verification are required to develop new methods of therapy, especially for diffuse forms of neoplasms.

[«Cavernous angiomas» of the brainstem. Clinical manifestations, diagnosis and treatment results]

Introduction

In the current literature, brainstem hematomas and various types of vascular micromalformations are combined into the one group of diseases under the general name «cavernous angioma» (CA). This approach does not make it possible to accurately determine the indications for surgery and predict postoperative outcomes.

Objective

To analyze our own experience in the diagnosis and treatment of patients with the brainstem CA.

Material and methods

There were 515 patients with CA of the brainstem (surgery - 322, conservative treatment - 193 patients) with a follow-up period of more than 5 years. Follow-up survey implied neurological examination, analysis of Karnofsky score, MRI and CT data.

Results

We identified two main groups of patients after comparison of MRI data, intraoperative findings and biopsy data: group 1 - hematomas (191 patients, 59%), group 2 - CA (131 patients, 41%). Each group was characterized by own clinical and radiological features. Postoperative outcomes depended on the disease. Debridement of hematoma ensured early postoperative improvement in 63% of patients, no changes in 21% of cases and impairment in 16% of patients. Less favorable results were observed in patients with CA and no signs of hemorrhage. Clinical impairment occurred in 73% of cases, improvement - only in 5% of patients. The most significant regression of neurological symptoms in long-term postoperative period was observed in patients with hematomas (92% of patients). These ones noted much better clinical state compared with preoperative condition.

Conclusions

The type of brain lesion is an important predictor to determine treatment approach. Postoperative outcomes differ significantly in patients with the brainstem hematoma and CA.

[Posterior decompression of the craniovertebral junction in syringomyelia combined with Chiari-1 malformation in children]

OBJECTIVE

to develop the algorithm for defining the amount of posterior decompression of the craniovertebral junction in children with syringomyelia combined with Chiari-1 malformation.

MATERIAL AND METHODS

Sixty eight children with syringomyelia and Chiari-1 malformation, under age of 18 years, underwent posterior decompression of the craniovertebral junction (PDCVJ) in the period from January 2001 to June 2016. Seven (10%) patients underwent extradural decompression (EDD), 16 (24%) patients underwent extra-arachnoid duraplasty (EAD), 25 (37%) patients underwent intra-arachnoid dissection (IAD) and duraplasty, and 20 (29%) patients underwent PDCVJ and placement of a fourth ventricle-subarachnoid shunt.

RESULTS

Clinical improvement occurred in 85% of patients, and stabilization was observed in 11% of patients. Syringomyelia regressed in 78% of cases. There were no complications associated with EDD; however, re-operation was required in 3 (43%) cases. In the case of EAD, treatment results were satisfactory in 11 (79%) patients; re-operation was required in 2 (12.5%) cases; there were no complications in the early postoperative period. The highest complication rate of 6 (30%) cases was associated with shunt placement and duraplasty. However, long-term results in this group of patients were satisfactory in 16 (94%) cases, and MRI-based positive changes were observed in 100% of cases.

CONCLUSION

According to our analysis, EAD is the method of choice for PDCVJ in children with syringomyelia and Chiari-1 malformation without myelopathy symptoms. In the presence of myelopathy symptoms, intra-arachnoid dissection (with or without shunting) is an acceptable alternative. To our opinion, the use of EDD in syringomyelia is unadvisable.

A giant hyperostotic parasagittal meningioma in a child with neurofibromatosis type II (a case report and literature review)

Large parasagittal meningiomas, in particular hyperostotic ones, in children are rare and problematic in the differential diagnosis. The literature reports only single clinical cases related to this issue; opinions about the indications, surgical treatment options, and prognosis are contradictory. This paper presents a clinical case of a hyperostotic parasagittal meningioma with intra-extracranial growth in a 10-year-old boy with neurofibromatosis type II significantly worsening the prognosis. We discuss the epidemiological and clinical features of childhood meningiomas and issues of their diagnosis, treatment, and prognosis.

Basal ganglia germinomas in children. Four clinical cases and a literature review

Basal ganglia germinomas are a specific group of intracranial germinomas. Their early diagnosis is complicated due to their atypical localization and diversity of neuroimaging and clinical signs.

MATERIAL AND METHODS

We describe 4 cases of basal ganglia germinoma in boys of 13, 14, 15, and 16 years of age. The medical history data, clinical features, neuroimaging and histological characteristics of basal ganglia germonomas, and preliminary results of the treatment are presented.

CONCLUSION

Basal ganglia germinomas are usually verified at the late stage of the disease when patients are detected with extended lesions of the basal ganglia and severe neurological and neuroendocrine deficits. This situation is due to clinical and imaging signs that are untypical of common germinomas.

Characteristics of medulloblastoma in children under age of three years

We present a series of 51 medulloblastoma in children under three years, collected in N.N. Burdenko Neurosurgical Institute from 2000 to 2010. 57% of the tumors showed desmoplastic/nodular histology. Performed fluorescence in situ hybridization (FISH) analysis revealed the MYC oncogene amplification in 4%, the MYCN oncogene amplification - in 8%, isochromosome 17q - in 16% of cases. 9q deletion was found in 8% of desmoplastic/ nodular medulloblastomas. Our results showed that desmoplastic/nodular medulloblastoma has a positive predictive value for progression-free survival. Another feature of a biology of medulloblastomas in children younger than three years is the lack of nuclear accumulation of beta-catenin, and 6q deletion. Medulloblastomas with MYCN oncogene amplification often exhibit desmoplastic/nodular histology and a relatively favorable outcome. The most unfavorable prognostic marker is the MYC oncogene amplification, which in our series of 100% combined with the large cell/anaplastic medulloblastoma and isochromosome 17q - such tumors should be included in the "high risk" protocol.

[Diffuse bithalamic astrocytomas in children and adults]

Diffuse bithalamic glioma is rare entity. A few cases have been described so far. We present the data of 13 patients (both children and adults) with diffuse bithalamic gliomas observed and treated at Burdenko Neurosurgery Institute within the period of 2004-2011. Age of patients varied from 3 to 29 y.o. Bithalamic gliomas appear as symmetric enlargement of both thalami on MRI with frequent spreading to adjacent structures (brainstem, temporal lobes). Histologically they appear as astrocytomas (Grade II-IV). Bithalamic gliomas posess different clinical course. There is no indication for surgical treatment because of diffuse growth of these tumors. Stereotactic biopsy is indicated to verify histological origin. Treatment of bithalamic gliomas confined with radio- and chemotherapy. In cases with obstructive hydrocephalus CSF diverting operations are indicated. Attempts of surgical excision lead to worsening of patient's neurological condition. Most patients with bithalamic gliomas have unfavorable prognosis. Tumors remain stable with adjuvant therapy for a very short period of time in most cases. Benign course of this pathology with long-term follow-up is observed only in a few cases.

[Arteriovenous malformations of the Galen vein: results of treatment]

We performed retrospective and prospective analysis of surgical treatment of arteriovenous malformations of vein of Galen. Since 1987 till 2009 90 patients were operated in Burdenko Neurosurgical Institute. Age varied between 1 month and 38 years, 69 patients were children below 10. The paper describes main techniques for early diagnosis of the disease, its manifestation depending on age and type of malformation, treatment modalities, early postoperative and follow-up results. Endovascular treatment was applied in 75 (83.3%) patients. Complications with persistent neurological deficit after endovascular occlusion were observed in 10 (16%) patients, 2 patients died shortly after surgery.

CONCLUSION

endovascular surgery is the treatment of choice in arteriovenous malformations of vein of Galen; optimal age for endovascular procedure is 4-5 months; observation in asymptomatic course is ineffective.

[Stereotactic radiotherapy and radiosurgery in treatment of patients with deep-seated pilocytic astrocytomas]

Pilocytic astrocytoma (PA) is a low-grade glial tumor (WHO grade I) with predominant occurrence in pediatric patients. According to many authors, stereotactic radiosurgery (SRS) and radiotherapy (SRT) promote long-term remission or retardation of tumor progression in patients with in inoperable lesions after incomplete resection or recurrence. Therefore it is essential to determine the role of SRS and SRT in complex management of patients with deep-seated PA. Since April 2005 till May 2010 101 patient with intracranial PA was treated in department for radiation therapy of Burdenko Neurosurgical Institute. The series consisted of 70 pediatric patients (below 17 years inclusively) and 31 adults, of them--51 male and 50 female patients. Mean age was 15.1 years (9.8 years in children and 28.7 in adults). In 90 patients (89.2%) tumors were previously histologically verified (tumor resection in 83 cases and biopsy in 7). In 11 (10.8%) patients diagnosis of PA was based on clinical and neurovisualization data. In most cases SRT (66 (66.3%) patients) was preformed, the rest 35 (34.7%) patients were treated by SRS. Median follow-up from the onset of disease reached 52 months (2-228 months). Catamnestic data were available in 88 (87%) patients. By the end of catamnestic follow-up (December 2010) 87 (98.8%) patients treated by SRS and SRT were alive. Median follow-up from the start of radiation treatment was 22.7 months (6-60 months). Progression of tumor was observed in 20 patients (22.7%), in 18 of them due to cyst growth. 18 patients were reoperated. In 12 operated patients histological examination and its comparative analysis were performed. We found that alterations in the tumor tissue, accompanied by regression of solid component and progression of cystic portion, represent reactive-degenerative changes in the tumor as a consequence of radiation-induced pathomorphism. SRS and STR are effective techniques for treatment of patients with primary and recurrent PA despite regardless of localization of the tumor. There procedures should be performed shortly after non-radical resection. Control of tumor growth by the present time (median follow-up is 22.7 months) reaches 98%. "Progression" of the tumor due to enlargement of cystic portion shortly after SRT and SRS represents reactive-degenerative alterations in the tumor tissue and should not be evaluated as true recurrence; without neurological deterioration these cases do not require special treatment.

[Diffuse hyperplasia of choroid plexuses of lateral ventricles]

Diffuse hyperplasia of choroid plexuses of lateral ventricles is extremely rare entity which is characterized by diffusely increased size of choroid plexuses along the entire choroid fissure and CSF hypersecretion. This disease, initially described by Davis in 1924, may be fallaciously diagnosed as bilateral choroidpapillomas. We present a case of diffuse hyperplasia of choroid plexuses of lateral ventricles in a female infant.

[Stereotactic radiosurgery in treatment of patients with hypothalamic hamartomas]

Hypothalamic hamartoma (HH) is malformation of the brain manifesting by paroxysmal disorders (gelastic seizures) and endocrine disorders (mostly precocious sexual development). Surgical resection of HH is associated with the risk of severe neurological and neuroendocrine complications. Alternative ways of treatment are being investigasted. Stereotactic radiosurgery is one of the leading techniques in treatment of pharmacoresistant seizures due to high effectiveness and low complication rate. Since 2005 till 2009 7 patients with HH were treated in Burdenko Moscow Neurosurgical Institute. Age of patients varied between 9 months and 20 years 9 mean - 8.5 years). In all cases the disease manifested by gelastic seizures with frequency differing between 2-3 per months and 17 per day. All patients received long-term combined anticonvulsant treatment (using valproates, carbamazepine, lamotrigine, oxcarbazepine, topiramate) with temporary and insufficient effect or without any effect. In 4 patients frequency of seizures increased during anticonvulsant therapy. I patient had been operated (partial resection of HH) with temporary effect which consisted of decrease in frequency of seizures for 8 months; later frequency of paroxysms increased. Main indications to radiosurgical treatment included progressive course of disease, low effectiveness of anticonvulsant therapy and high risk of direct surgical treatment. 6 patients were treated using linear accelerator "Novalis" and 1 using "Cyber-knife". Treatment was performed under pharmacological sedation (midazolam, ketamine). Marginal dose was 11-18 Gy (mean 15.7 Gy). Volume of hamartomas was 0.3-3 cm3. Follow-up period varied between 3 and 50 months. Decreased frequency of seizures was observed in 100% of cases. Stereotactic radiosurgery is an effective and safe method of treatment for HH and may be considered as treatment of choice for pharmacoresistant seizures caused by HH.

[Aneurysms of cerebral arteries in children and adolescents]

BACKGROUND

Intracranial aneurysms are rare lesions in children and adolescents and their epidemiology, clinical and anatomic features are poorly understood. Aim of the study was to reveal the specific features of cerebral aneurysms in children and adolescents and to develop guidelines for management of these patients.

MATERIALS AND METHODS

The study was performed on consecutive series of 125 patients under 18 years of age harboring 145 aneurysms. All of them were treated in Burdenko Neurosurgical Institute (Moscow, Russia) from 1987 to 2007.

RESULTS

Specific features of pediatric aneurysms include: high incidence on a background of connective tissue disorder (42%) and abnormalities of circle of Willis (20%), frequent localization in bifurcation of internal carotid artery (13.8%), its cavernous segment (17.9%), or in posterior part of circle of Willis (23.5%). In children giant aneurysms were observed in 31.7% of cases, fusiform in 19.3% and partially thrombosed in 33.8%. Complications of aneurysms in children with hemorrhagic type of course included recurrent hemorrhages (42.9%), hematomas (31%), hydrocephalus (16.7%) and seizures (33.3%). Generally, 107 pediatric patients (85.6%) with 118 aneurysm (81.4%) were operated. Microsurgical treatment was performed in 57% of patients and endovascular procedures in 43% In the series of 107 operated patients we observed excellent early postoperative results in 53 cases (49.5%), good in 45 (42.1%) and poor in 9 (8.4%). Postoperative mortality was 0.95% (1 patient).

CONCLUSION

Considerable proportion of complex aneurysms in children and adolescents produces certain difficulties of treatment; however, due to good functional outcomes in this age group the range of causes of denial must be minimized.

[Vein of Galen malformations in children]

The literature review deals with historical stages of understanding of vein of Galen AVM pathogenesis in children up to state-of-art considerations. The authors analyzed existing classifications, clinical presentation, variants of natural course, problems of diagnostics and management of these patients. Causes of complications and possible ways for their prevention are also discussed.

[Giant cavernous malformation of the cerebellum in a baby]

The paper presents a rare case of successful removal of giant cavernous malformation of the cerebellum in a baby. It describes the specific features of differential diagnosis of space-occupying lesions of the posterior cranial fossa in infants in detail.

[Analysis of the results of surgical treatment for symptomatic epilepsy caused by temporal lobar neoplasms]

The present study involves the analysis of the results of surgical treatment in 35 patients with drug-resistant epilepsy caused by local temporal lobar lesions: glioma without growth (n = 31), gliosis (n = 1), and cavernoma (n = 3). The medial location of neoplasms involving the hippocampus was noted in 25 cases, their extrahippocampal location was observed in 10 cases. The history of seizures was 2 to 18 years; the duration of a postoperative follow-up was 1 to 6 years. Electrocorticographic and EEG findings indicated that in all cases the eliptogenic zone was located in the medial portions of the temporal lobes at the site of lesion. The first stage of surgery was to remove a neoplasm; the adjacent portions of an epileptogenic zone were resected only with preserved convulsive activity in the surrounding areas. Good results (Classes I-II) were observed in cases of the medial location of a lesion in both total removal of a neoplasm and additional resections; in the group of patients the results were better than in routine removal (seizures ceasing in 4 of 5 and in 3 of 12 patients, respectively). Bad results (Classes III-V) were noted with partial removal of a neoplasm from the medial portions (n = 4), there were much better results (Classes I-II) with its total removal from the medial portions and with its partial removal from other areas. With total removal of extrahippocampal neoplasms, seizures were retained (Classes III-IV); additional resections of neocortical zones (n = 2) failed to improve the results of treatment. With resections in the entorial cortical area, the results were better (Class II). Our findings confirm that hippocampal removal plays an important role in symptomatic temporal epilepsy for an adequate monitoring of seizures.

[Experience in surgical treatment of patients with focal forms of temporal epilepsy]

Fifteen patients with focal lesions of temporal epilepsy were examined before and 6 months to 4 years after surgery. There were low-grade gliomas in 13 cases, muscle tissue heterotopy in 1 case, and medial temporal sclerosis in 1. Epileptogenic lesions were localized in the medial structures of the temporal lobe in 10 cases and in the lateral temporal regions in 5 cases. Comprehensive neurophysiological study, including intraoperative electrocorticography, was used to identify an epileptogenic zone (EZ). EZs were found in the medial structures on the affected side in all patients. Lesionectomies were performed in all cases. It was combined with medial resection in 12 cases (it was done in 10 patients until epileptic activity disappeared). Nine patients stopped having seizures after surgery. One patient had only auras. Improvements were slight in 5 patients. A relationship was found between the surgical outcomes and the site of a lesion and EZ. They authors conclude that complete recovery may occur in cases with medial locations of a lesion and EZ. The outcomes of surgery are much poorer in cases with the lateral sites of an lesion and in those with the medial site of EZ.

[A cryptococcal granuloma of the midbrain]

The paper describes the most infrequent case of cryptococcal granuloma of the midbrain in a HIV-negative female patient aged 41 years. The patient with midbrain lesion without signs of meningitis was found to have a bulky midbrain opercular formation that was regarded as a nodal glioma. The diagnosis of cryptococcal granuloma was established after removal of the formation (via occipito-transtentorial access with dissection of the lamina tecti) and pathomorphological examination. Microbiological studies verified the diagnosis. Despite the initiation of specific treatment with amphotericin B, the patient died on day 12 following surgery for cryptococcal meningoencephalitis.

[Intraoprative identification and monitoring of motor structures of the brain stem]

The purpose of this work was to evaluate the method of identification of motor structures of the bottom of the IV ventricle in order to find the zone through which it is possible to safely approach the bulky formation and to assess the efficacy of subsequent monitoring of these structures for the prevention of their intraoperative injury. Fourteen patients with bulky tumors of the caudal portions of the brain stem aged 4 to 57 were examined. Motor structures of the brain stem (nerves VII or IX, X, and XII, depending on the site of injury) were identified by direct electrostimulation of the surface of the rhomboid fossa and recording of the motor functions by mechanography of EMG. The results indicate that intraoperative identification of motor structures followed by monitoring thereof is a useful instrument which helps reduce the surgical risk of injuring these structures during surgery on the brain stem.

[The prognostic significance of the histological characteristics of cerebellar astrocytomas in children]

The late term results of surgical treatment of cerebellar astrocytomas in children are compared with the specific features of the histological structure of the tumor and the volume of the surgical intervention. The authors distinguish the prognostically unfavourable characteristics of the histological structure of cerebellar astrocytomas (mitotic figures, even occasional, polymorphism of cells or nuclei, combination of dense cellularity with proliferation of endothelium in the vessels) which determine the prognosis in total or subtotal removal of the tumor. The index "volume of operation" acquires highest prognostic significance in subtotal removal of the tumor. A recurrent tumor develops in all cases after subtotal removal, irrespective of the histological structure.

[The efficacy of gamma teletherapy in the combined treatment of medulloblastomas in the posterior cranial fossa of children]

The results of radiation therapy conducted after various schemes were compared in 77 patients operated on for medulloblastoma of the posterior cranial fossa: 1. irradiation of the posterior cranial fossa area; 2. irradiation of this area and the entire length of the spinal marrow; 3. total irradiation of the CNS. Stages in a metastatic process necessitate irradiation in stages, i.e. irradiation of the posterior cranial fossa and the length of the spinal marrow followed by irradiation of the cerebral hemispheres one year after the operation. Total irradiation of the CNS shortly after the operation is recommended only in the presence of early metastases.

[EEg changes after removal of craniopharyngiomas in children]

Electroencephalograms (EEG) were studied after removal of craniopharyngioma in 75 children. Correlation of the character of ECG changes with the severity of the clinical condition was revealed. Maximally manifested pathological EEG activity of the central areas of the cortex and a phase character of the EEG changes with different duration of the phases determined by the patient's condition were common to all patients, irrespective of the severity of their condition which was determined by the degree of the pathological changes in the thalamo-hypothalamic structures. Prognostic signs of the EEG changes were identified, which characterized a favorable or a complicated course of the postoperative process.

[Late results of surgical treatment of tumors of the posterior cranial fossa in children]

The work is based on the analysis of the course followed by the disease in 533 patients aged 18 months to 15 years who underwent operation for benign and malignant tumors of the cerebellum and fourth ventricle in the period between 1964 and 1975. The late results were appraised in 1980-1981 in 269 patients. The minimum follow-up period of the surviving patients is 5 years, the maximum period 16 years. Catamnestic study showed that among all tumors of the posterior cranial fossa in children, only cerebellar astrocytoma and chorioidpapilloma were marked by a favourable late prognosis. Total sparing removal of these tumors leads to practical recovery of most patients.