Segmentation of pre- and posttreatment diffuse glioma tissue subregions including resection cavities.

Background: Evaluating longitudinal changes in gliomas is a time-intensive process with significant interrater variability. Automated segmentation could reduce interrater variability and increase workflow efficiency for assessment of treatment response. We sought to evaluate whether neural networks would be comparable to expert assessment of pre- and posttreatment diffuse gliomas tissue subregions including resection cavities. Methods: A retrospective cohort of 647 MRIs of patients with diffuse gliomas (average 55.1 years; 29%/36%/34% female/male/unknown; 396 pretreatment and 251 posttreatment, median 237 days post-surgery) from 7 publicly available repositories in The Cancer Imaging Archive were split into training (536) and test/generalization (111) samples. T1, T1-post-contrast, T2, and FLAIR images were used as inputs into a 3D nnU-Net to predict 3 tumor subregions and resection cavities. We evaluated the performance of networks trained on pretreatment training cases (Pre-Rx network), posttreatment training cases (Post-Rx network), and both pre- and posttreatment cases (Combined networks). Results: Segmentation performance was as good as or better than interrater reliability with median dice scores for main tumor subregions ranging from 0.82 to 0.94 and strong correlations between manually segmented and predicted total lesion volumes (0.94 < R 2 values < 0.98). The Combined network performed similarly to the Pre-Rx network on pretreatment cases and the Post-Rx network on posttreatment cases with fewer false positive resection cavities (7% vs 59%). Conclusions: Neural networks that accurately segment pre- and posttreatment diffuse gliomas have the potential to improve response assessment in clinical trials and reduce provider burden and errors in measurement.

Deep Learning Segmentation of Infiltrative and Enhancing Cellular Tumor at Pre- and Posttreatment Multishell Diffusion MRI of Glioblastoma.

Purpose To develop and validate a deep learning (DL) method to detect and segment enhancing and nonenhancing cellular tumor on pre- and posttreatment MRI scans in patients with glioblastoma and to predict overall survival (OS) and progression-free survival (PFS). Materials and Methods This retrospective study included 1397 MRI scans in 1297 patients with glioblastoma, including an internal set of 243 MRI scans (January 2010 to June 2022) for model training and cross-validation and four external test cohorts. Cellular tumor maps were segmented by two radiologists on the basis of imaging, clinical history, and pathologic findings. Multimodal MRI data with perfusion and multishell diffusion imaging were inputted into a nnU-Net DL model to segment cellular tumor. Segmentation performance (Dice score) and performance in distinguishing recurrent tumor from posttreatment changes (area under the receiver operating characteristic curve [AUC]) were quantified. Model performance in predicting OS and PFS was assessed using Cox multivariable analysis. Results A cohort of 178 patients (mean age, 56 years ± 13 [SD]; 116 male, 62 female) with 243 MRI timepoints, as well as four external datasets with 55, 70, 610, and 419 MRI timepoints, respectively, were evaluated. The median Dice score was 0.79 (IQR, 0.53-0.89), and the AUC for detecting residual or recurrent tumor was 0.84 (95% CI: 0.79, 0.89). In the internal test set, estimated cellular tumor volume was significantly associated with OS (hazard ratio [HR] = 1.04 per milliliter; P < .001) and PFS (HR = 1.04 per milliliter; P < .001) after adjustment for age, sex, and gross total resection (GTR) status. In the external test sets, estimated cellular tumor volume was significantly associated with OS (HR = 1.01 per milliliter; P < .001) after adjustment for age, sex, and GTR status. Conclusion A DL model incorporating advanced imaging could accurately segment enhancing and nonenhancing cellular tumor, distinguish recurrent or residual tumor from posttreatment changes, and predict OS and PFS in patients with glioblastoma. Keywords: Segmentation, Glioblastoma, Multishell Diffusion MRI Supplemental material is available for this article. © RSNA, 2024.

Management of recurrent giant hemangiopericytoma: illustrative cases.

BACKGROUND: Hemangiopericytoma (HPC) is a rare malignancy accounting for 0.4% of intracranial tumors. HPCs are characterized by local aggressiveness, high rates of recurrence, and a tendency to metastasize to extracranial sites. These features make management of HPCs challenging, often requiring a combination of radical resection and radiation. Given their rarity, optimal treatment algorithms remain undefined. OBSERVATIONS: The authors report a series of four patients who underwent resection of intracranial HPC. Mean age at presentation was 49.3 years. Three patients had reoperation for progression of residual tumor, and one patient was surgically retreated for recurrence. One patient received adjuvant radiotherapy following initial resection, and three patients received adjuvant radiotherapy following resection of recurrent or residual disease. There was one death in the series. Average progression-free survival and overall survival following the index procedure were 32.8 and 82 months, respectively. Progression occurred locally in all patients, with metastatic recurrence in one patient. LESSONS: The current gold-standard treatment for intracranial HPC consists of gross-total resection followed by radiation therapy. This approach allows satisfactory local control; however, given the tendency for these tumors to recur either locally or distally within or outside of the central nervous system, there is a need for salvage therapies to improve long-term outcomes for patients.

Bilateral Inferior Turbinate Flaps for Salvage Reconstruction after Proton Beam Radiotherapy for Clival Chordoma.

Clival chordoma is a rare, aggressive, notochord-derived tumor primarily managed with surgery via an endoscopic endonasal approach (EEA) and adjuvant proton beam radiotherapy. Reconstruction is commonly performed with a nasoseptal flap (NSF) at the time of initial surgery. While failures of the NSF are rare, they can occur following the initial surgery or in the setting of osteoradionecrosis. Salvage repair typically requires transfer of alternative vascularized tissues outside of the previously radiated field including regional scalp flaps such as pericranial or temporoparietal fascial flaps, or free vascularized tissue transfer. Here we describe the case of a 29-year-old woman with a history of clival chordoma with widespread skull base osteomyelitis secondary to NSF necrosis after proton beam radiotherapy. We describe successful skull base reconstruction with intranasal bilateral inferior turbinate flaps based on the sphenopalatine artery with lateral nasal wall extension, despite prior proton beam therapy and a failed prior vascularized intranasal reconstruction.

Surgical management of colloid cysts of the third ventricle: a single-institution comparison of endoscopic and microsurgical resection.

OBJECTIVE: Colloid cysts of the third ventricle are histologically benign lesions that can cause obstructive hydrocephalus and death. Historically, colloid cysts have been removed by open microsurgical approaches. More recently, minimally invasive endoscopic and port-based techniques have offered decreased complications and length of stay, with improved patient satisfaction. METHODS: A single-center retrospective analysis of patients with colloid cysts who underwent surgery at a large tertiary care hospital was performed. The cohort was assessed based on the surgical approach, comparing endoscopic resection to open microsurgical resection. The primary endpoint was rate of perioperative complications. Univariate analysis was used to assess several procedure-related variables and the cost of treatment. Multivariate analysis was used to assess predictors of perioperative complications. Total inpatient cost for each case was extracted from the health system financial database. RESULTS: The study included 78 patients with colloid cysts who underwent resection either via an endoscopic approach (n = 33) or through a craniotomy (n = 45) with an interhemispheric-transcallosal or transcortical-transventricular approach. Nearly all patients were symptomatic, and half had obstructive hydrocephalus. Endoscopic resection was associated with reduced operative time (3.2 vs 4.9 hours, p < 0.001); lower complication rate (6.1% vs 33.1%, p = 0.009); reduced length of stay (4.1 vs 8.9 days, p < 0.001); and improved discharge to home (100% vs 75.6%, p = 0.008) compared to microsurgical resection. Coagulated residual cyst wall remnants were more common after endoscopic resection (63.6% vs 19.0%, p < 0.001) although this was not associated with a significantly increased rate of reoperation for recurrence. The mean follow-up was longer in the microsurgical resection group (3.1 vs 4.9 years, p = 0.016). The total inpatient cost of endoscopic resection was, on average, one-half (47%) that of microsurgical resection. When complications were encountered, the total inpatient cost of microsurgical resection was 4 times greater than that of endoscopic resection where no major complications were observed. The increased cost-effectiveness of endoscopic resection remained during reoperation. CONCLUSIONS: Endoscopic resection of colloid cysts of the third ventricle offers a significant reduction in perioperative complications when compared to microsurgical resection. Endoscopic resection optimizes nearly all procedure-related variables compared to microsurgical resection, and reduces total inpatient cost by > 50%. However, endoscopic resection is associated with a significantly increased likelihood of residual coagulated cyst wall remnants that could increase the rate of reoperation for recurrence. Taken together, endoscopic resection represents a safe and effective minimally invasive approach for removal of colloid cysts.

The genomics and epigenetics of olfactory neuroblastoma: A systematic review.

BACKGROUND: Olfactory neuroblastoma (ONB) or esthesioneuroblastoma (ENB) is a rare malignancy of the nasal cavity believed to arise from the olfactory epithelium. The goal of this study was to systematically review the genomics, epigenetics, and cytogenetics of ONB and to understand the potential clinical implications of these studies. METHODS: A systematic literature review was performed for articles published before May 2020 using Cochrane, Embase, Pubmed, and Scopus databases. Inclusion criteria included genomics, cytogenetics, and epigenetics studies on ONB. Exclusion criteria included studies not in English or systematic reviews. Articles and abstracts were reviewed by two independent reviewers to reduce bias during article selection and synthesis of results. Of the 36 studies included in this review, 24 were research articles and 12 were abstracts. RESULTS: Although recurrent mutations among ONB tumors are uncommon, alterations in TP53, DMD, PIK3CA, NF1, CDKN2A, CDKN2C, CTNNB1, EGFR, APC, cKIT, cMET, PDGFRA, CDH1, FH, SMAD4, FGFR3 and IDH2 genes have been reported in several recent studies. In addition, cytogenetic studies revealed that the landscape of chromosomal aberrations varies widely amongst ONB tumors. CONCLUSIONS: The rare character of ONB has limited the sample size available for cytogenetic, genomic, and epigenetic studies and contributes to the limitations of this systematic review. Comprehensive genomic and epigenomic studies with larger cohorts are warranted to validate the initial reports summarized in this review and to identify potential therapeutic targets for ONB.

Hydrophilic polymer embolism identified in brain tumor specimens following Wada testing: A report of 2 cases.

Hydrophilic polymers are commonly used as coatings on intravascular medical devices. As intravascular procedures continue to increase in frequency, the risk of embolization of this material throughout the body has become evident. These emboli may be discovered incidentally but can result in serious complications including death. Here, we report the first two cases of hydrophilic polymer embolism (HPE) identified on brain tumor resection following Wada testing. One patient experienced multifocal vascular complications and diffuse cerebral edema, while the other had an uneventful postoperative course. Wada testing is frequently performed during preoperative planning prior to epilepsy surgery or the resection of tumors in eloquent brain regions. These cases demonstrate the need for increased recognition of this histologic finding to enable further correlation with clinical outcomes.

The role of indocyanine green fluorescence in endoscopic endonasal skull base surgery and its imaging correlations.

OBJECTIVE: The use of endoscope-integrated indocyanine green (E-ICG) has recently been introduced in skull base surgery. The quantitative correlation between E-ICG and T1-weighted gadolinium-enhanced (T1WGd) images for skull base tumors has not been previously assessed, to the authors' knowledge. In this study, the authors investigated the indications for use and the limitations of E-ICG and sought to correlate the endoscopic fluorescence pattern with MRI contrast enhancement. METHODS: Following IRB approval, 20 patients undergoing endoscopic endonasal skull base surgery between June 2017 and August 2018 were enrolled in the study. Tumor fluorescence was measured using a blue color value and blood fluorescence as a control. Signal intensities (SIs) of tumor T1WGd images were measured and the internal carotid artery (ICA) SI was used as a control. For pituitary adenoma, the pituitary gland fluorescence was also measured. The relationships between ICG fluorescence and MRI enhancement measurements were analyzed. RESULTS: Data showed that in pituitary adenoma there was a strong correlation between the ratios of gland/blood fluorescence to gland/ICA SI (n = 8; r = 0.92; p = 0.001) and tumor/blood fluorescence to tumor/ICA SI (n = 9; r = 0.82; p = 0.006). In other pathologies there was a strong correlation between the ratios of tumor/blood fluorescence and tumor/ICA SI (n = 9; r = 0.74; p = 0.022). The ICG fluorescence allowed perfusion assessment of the pituitary gland as well as of the nasoseptal flaps. Visualization of the surrounding vasculature was also feasible. CONCLUSIONS: Defining the indications and understanding the limitations are critical for the effective use of E-ICG. Tumor fluorescence seems to correlate with preoperative MRI contrast enhancement.

Initial Experience Using Intraoperative Magnetic Resonance Imaging During a Trans-Sulcal Tubular Retractor Approach for the Resection of Deep-Seated Brain Tumors: A Case Series.

BACKGROUND: Treatment of deep-seated subcortical intrinsic brain tumors remains challenging and may be improved with trans-sulcal tubular brain retraction techniques coupled with intraoperative magnetic resonance imaging (iMRI). OBJECTIVE: To conduct a preliminary assessment of feasibility and efficacy of iMRI in tubular retractor-guided resections of intrinsic brain tumors. METHODS: Assessment of this technique and impact upon outcomes were assessed in a preliminary series of brain tumor patients from 2 centers. RESULTS: Ten patients underwent resection with a tubular retractor system and iMRI. Mean age was 53.2 ± 9.0 yr (range: 37-61 yr, 80% male). Lesions included 6 gliomas (3 glioblastomas, 1 recurrent anaplastic astrocytoma, and 2 low-grade gliomas) and 4 brain metastases (1 renal cell, 1 breast, 1 lung, and 1 melanoma). Mean maximal tumor diameter was 2.9 ± 0.95 cm (range 1.2-4.3 cm). The iMRI demonstrated subtotal resection (STR) in 6 of 10 cases (60%); additional resection was performed in 5 of 6 cases (83%), reducing STR rate to 2 of 10 cases (20%), with both having tumor encroaching on eloquent structures. Seven patients (70%) were stable or improved neurologically immediately postoperatively. Three patients (30%) had new postoperative neurological deficits, 2 of which were transient. Average hospital length of stay was 3.4 ± 2.0 d (range: 1-7 d). CONCLUSION: Combining iMRI with tubular brain retraction techniques is feasible and may improve the extent of resection of deep-seated intrinsic brain tumors that are incompletely visualized with the smaller surgical exposure of tubular retractors.

Upfront Magnetic Resonance Imaging-Guided Stereotactic Laser-Ablation in Newly Diagnosed Glioblastoma: A Multicenter Review of Survival Outcomes Compared to a Matched Cohort of Biopsy-Only Patients.

BACKGROUND: Laser ablation (LA) is used as an upfront treatment in patients with deep seated newly diagnosed Glioblastoma (nGBM). OBJECTIVE: To evaluate the outcomes of LA in patients with nGBM and compare them with a matched biopsy-only cohort. METHODS: Twenty-four nGBM patients underwent upfront LA at Cleveland clinic, Washington University in St. Louis, and Yale University (6/2011-12/2014) followed by chemo/radiotherapy. Also, 24 out of 171 nGBM patients with biopsy followed by chemo/radiotherapy were matched based on age (< 70 vs ≥ 70), gender, tumor location (deep vs lobar), and volume (<11 cc vs ≥11 cc). Progression-free survival (PFS), overall survival (OS), and disease-specific PFS and OS were outcome measures. Three prognostic groups were identified based on extent of tumor ablation by thermal-damage-threshold (TDT)-lines. RESULTS: The median tumor volume in LA (n = 24) and biopsy only (n = 24) groups was 9.3 cm3 and 8.2 cm3 respectively. Overall, median estimate of OS and PFS in LA cohort was 14.4 and 4.3 mo compared to 15.8 mo and 5.9 mo for biopsy only cohort. On multivariate analysis, favorable TDT-line prognostic groups were associated with lower incidence of disease specific death (P = .03) and progression (P = .05) compared to other groups including biopsy only cohort. Only age (<70 yr, P = .02) and tumor volume (<11 cc, P = .03) were favorable prognostic factors for OS. CONCLUSION: The maximum tumor coverage by LA followed by radiation/chemotherapy is an effective treatment modality in patients with nGBM, compared to biopsy only cohort. The TDT-line prognostic groups were independent predictor of disease specific death and progression after LA.

Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy for Glioblastoma of the Corpus Callosum.

BACKGROUND: Glioblastoma of the corpus callosum is particularly difficult to treat, as the morbidity of surgical resection generally outweighs the potential survival benefit. Laser interstitial thermal therapy (LITT) is a safe and effective treatment option for difficult to access malignant gliomas of the thalamus and insula. OBJECTIVE: To assess the safety and efficacy of LITT for the treatment of glioblastoma of the corpus callosum. METHODS: We performed a multicenter retrospective analysis of prospectively collected data. The primary endpoint was the safety and efficacy of LITT as a treatment for glioblastoma of the corpus callosum. Secondary endpoints included tumor coverage at thermal damage thresholds, median survival, and change in Karnofsky Performance Scale score 1 mo after treatment. RESULTS: The study included patients with de novo or recurrent glioblastoma of the corpus callosum (n = 15). Mean patient age was 54.7 yr. Mean pretreatment Karnofsky Performance Scale score was 80.7 and there was no significant difference between subgroups. Mean tumor volume was 18.7 cm3. Hemiparesis occurred in 26.6% of patients. Complications were more frequent in patients with tumors >15 cm3 (RR 6.1, P = .009) and were associated with a 32% decrease in survival postLITT. Median progression-free survival, survival postLITT, and overall survival were 3.4, 7.2, and 18.2 mo, respectively. CONCLUSION: LITT is a safe and effective treatment for glioblastoma of the corpus callosum and provides survival benefit comparable to subtotal surgical resection with adjuvant chemoradiation. LITT-associated complications are related to tumor volume and can be nearly eliminated by limiting the procedure to tumors of 15 cm3 or less.

Natural history of colloid cysts of the third ventricle.

OBJECTIVE Colloid cysts are rare, histologically benign lesions that may result in obstructive hydrocephalus and death. Understanding the natural history of colloid cysts has been challenging given their low incidence and the small number of cases in most reported series. This has complicated efforts to establish reliable prognostic factors and surgical indications, particularly for asymptomatic patients with incidental lesions. Risk factors for obstructive hydrocephalus in the setting of colloid cysts remain poorly defined, and there are no grading scales on which to develop standard management strategies. METHODS The authors performed a single-center retrospective review of all cases of colloid cysts of the third ventricle treated over nearly 2 decades at Washington University. Univariate analysis was used to identify clinical, imaging, and anatomical factors associated with 2 outcome variables: symptomatic clinical status and presentation with obstructive hydrocephalus. A risk-prediction model was defined using bootstrapped logistic regression. Predictive factors were then combined into a simple 5-point clinical scale referred to as the Colloid Cyst Risk Score (CCRS), and this was evaluated with receiver-operator characteristics. RESULTS The study included 163 colloid cysts, more than half of which were discovered incidentally. More than half of the incidental cysts (58%) were followed with surveillance neuroimaging (mean follow-up 5.1 years). Five patients with incidental cysts (8.8%) progressed and underwent resection. No patient with an incidental, asymptomatic colloid cyst experienced acute obstructive hydrocephalus or sudden neurological deterioration in the absence of antecedent trauma. Nearly half (46.2%) of symptomatic patients presented with hydrocephalus. Eight patients (12.3%) presented acutely, and there were 2 deaths due to obstructive hydrocephalus and herniation. The authors identified several factors that were strongly correlated with the 2 outcome variables and defined third ventricle risk zones where colloid cysts can cause obstructive hydrocephalus. No patient with a lesion outside these risk zones presented with obstructive hydrocephalus. The CCRS had significant predictive capacity for symptomatic clinical status (area under the curve [AUC] 0.917) and obstructive hydrocephalus (AUC 0.845). A CCRS ≥ 4 was significantly associated with obstructive hydrocephalus (p < 0.0001, RR 19.4). CONCLUSIONS Patients with incidentally discovered colloid cysts can experience both lesion enlargement and symptom progression or less commonly, contraction and symptom regression. Incidental lesions rarely cause acute obstructive hydrocephalus or sudden neurological deterioration in the absence of antecedent trauma. Nearly one-half of patients with symptomatic colloid cysts present with obstructive hydrocephalus, which has an associated 3.1% risk of death. The CCRS is a simple 5-point clinical tool that can be used to identify symptomatic lesions and stratify the risk of obstructive hydrocephalus. External validation of the CCRS will be necessary before objective surgical indications can be established. Surgical intervention should be considered for all patients with CCRS ≥ 4, as they represent the high-risk subgroup.

Subependymal giant cell astrocytoma in the absence of tuberous sclerosis complex: case report.

The authors report the case of a 14-year-old male with a subependymal giant cell astrocytoma (SEGA) that occurred in the absence of tuberous sclerosis complex (TSC). The patient presented with progressive headache and the sudden onset of nausea and vomiting. Neuroimaging revealed an enhancing left ventricular mass located in the region of the foramen of Monro with significant mass effect and midline shift. The lesion had radiographic characteristics of SEGA; however, the diagnosis remained unclear given the absence of clinical features of TSC. The patient underwent gross-total resection of the tumor with resolution of his symptoms. Although tumor histology was consistent with SEGA, genetic analysis of both germline and tumor DNA revealed no TSC1/2 mutations. Similarly, a comprehensive clinical evaluation failed to reveal any clinical features characteristic of TSC. Few cases of SEGA without clinical or genetic evidence of TSC have been reported. The histogenesis, genetics, and clinical approach to this rare lesion are briefly reviewed.

Molecular and cellular heterogeneity: the hallmark of glioblastoma.

There has been increasing awareness that glioblastoma, which may seem histopathologically similar across many tumors, actually represents a group of molecularly distinct tumors. Emerging evidence suggests that cells even within the same tumor exhibit wide-ranging molecular diversity. Parallel to the discoveries of molecular heterogeneity among tumors and their individual cells, intense investigation of the cellular biology of glioblastoma has revealed that not all cancer cells within a given tumor behave the same. The identification of a subpopulation of brain tumor cells termed "glioblastoma cancer stem cells" or "tumor-initiating cells" has implications for the management of glioblastoma. This focused review will therefore summarize emerging concepts on the molecular and cellular heterogeneity of glioblastoma and emphasize that we should begin to consider each individual glioblastoma to be an ensemble of molecularly distinct subclones that reflect a spectrum of dynamic cell states.

Acalvaria.

Acalvaria is a rare congenital malformation characterized by an absence of skin and skull. The authors describe a newborn at an estimated 38 weeks gestational age who was delivered via cesarean section from a 32-year-old mother. Upon delivery, the child was noted to have a frontal encephalocele and an absence of calvaria including skull and skin overlying the brain. A thin membrane representing dura mater was overlying the cortical tissue. After multiple craniofacial operations, including repair of the encephalocele and application of cultured keratinocytes over the rostral defect, the patient demonstrated significant closure of the calvarial defect and was alive at an age of more than 17 months with near-average development.

Layer-specific CREB target gene induction in human neocortical epilepsy.

Epilepsy is a disorder of recurrent seizures that affects 1% of the population. To understand why some areas of cerebral cortex produce seizures and others do not, we identified differentially expressed genes in human epileptic neocortex compared with nearby regions that did not produce seizures. The transcriptome that emerged strongly implicates MAPK signaling and CREB-dependent transcription, with 74% of differentially expressed genes containing a cAMP response element (CRE) in their proximal promoter, more than half of which are conserved. Despite the absence of recent seizures in these patients, epileptic brain regions prone to seizures showed persistent activation of ERK and CREB. Persistent CREB activation was directly linked to CREB-dependent gene transcription by chromatin immunoprecipitation that showed phosphorylated CREB constitutively associated with the proximal promoters of many of the induced target genes involved in neuronal signaling, excitability, and synaptic plasticity. A distinct spatial pattern of ERK activation was seen in superficial axodendritic processes of epileptic neocortex that colocalized with both CREB phosphorylation and CREB target gene induction in well demarcated populations of layer 2/3 neurons. These same neuronal lamina showed a marked increase in synaptic density. The findings generated in this study generate a robust and spatially restricted pattern of epileptic biomarkers and associated synaptic changes that could lead to new mechanistic insights and potential therapeutic targets for human epilepsy.

Advances in the management of subependymal giant cell astrocytoma.

BACKGROUND: Subependymal giant cell astrocytoma (SEGA) is the most common central nervous system tumor in patients with tuberous sclerosis complex (TSC). Although these lesions are generally benign and non-infiltrative, they commonly arise in the region of the foramen of Monro, where they can cause obstructive hydrocephalus and sudden death. METHODS: Surgical resection has been, and presently remains, the standard treatment for SEGAs demonstrating serial growth on neuroimaging in the setting of symptomatic hydrocephalus or progressive ventriculomegaly. DISCUSSION: Surgery can be curative; however, not all SEGAs are amenable to safe and complete resection. Gamma Knife stereotactic radiosurgery provides another treatment option but has highly variable response rates with limited data demonstrating its efficacy. Newer medical therapy targeting mammalian target of rapamycin (mTOR), the key protein kinase that is constitutively activated in TSC, has demonstrated promising results in recent clinical trials. In both case reports and clinical trials, treatment with mTOR inhibitors results in a significant reduction in SEGA volume and improvement or resolution of ventriculomegaly. This has led to the approval of everolimus for the treatment of SEGA in tuberous sclerosis patients who are not candidates for surgery. This review summarizes the surgical and medical management of SEGA in patients with TSC.

Gliosarcoma with multiple extracranial metastases: case report and review of the literature.

Gliosarcoma is a rare malignant neoplasm of the central nervous system with a propensity for metastasis. There are fewer than 20 reported cases of extracranial metastases of gliosarcoma with the majority of cases reflecting a tendency for hematogenous dissemination. Here we describe the case of a 47-year-old man who developed pervasive extracranial metastases from a temporal gliosarcoma following radio- and chemotherapy for a primary glioblastoma. The patient initially presented with progressively worsening headaches, left-sided weakness and numbness associated with right temporo-parietal mass for which he underwent craniotomy with stereotactic gross-total excision. Two months postoperatively, interstitial brachytherapy and external beam radiotherapy were initiated. The patient initially declined chemotherapy. The tumor recurred twice and the patient underwent re-operation and multiple courses of chemotherapy; histopathological diagnosis remained glioblastoma multiforme. Nineteen months following initial resection the patient's clinical status deteriorated and CT scan demonstrated multiple intrathoracic, hepatic and splenic lesions. Postmortem examination revealed widespread, infiltrating gliosarcoma with intravascular gliomatosis and extensive visceral metastases. This is the first report of pervasive extracranial metastases to numerous sites, several of which have not been previously reported. The histogenesis and the potential role of therapeutic irradiation in the development of gliosarcoma are briefly reviewed.

A common pattern of persistent gene activation in human neocortical epileptic foci.

Epilepsy is a disease of recurrent seizures that can develop after a wide range of brain insults. Although surgical resection of focal regions of seizure onset can result in clinical improvement, the molecular mechanisms that produce and maintain focal hyperexcitability are not understood. Here, we demonstrate a regional, persistent induction of a common group of genes in human epileptic neocortex in 17 patients with neocortical epilepsy, regardless of the underlying pathology. This relatively small group of common genes, identified using complementary DNA microarrays and confirmed with quantitative reverse transcription polymerase chain reaction and immunostaining, include the immediate early gene transcription factors EGR-1, EGR-2, and c-fos, with roles in learning and memory, and signaling genes such as the dual-specificity kinase/phosphatase MKP-3. Maximal expression of these genes was observed in neurons in neocortical layers II through IV. These neurons also showed persistent cyclic adenosine monophosphate response element binding protein (CREB) activation and nuclear translocation of EGR-2 and c-fos proteins. In two patients, local interictal epileptiform discharge frequencies correlated precisely with the expression of these genes, suggesting that these genes either are directly modulated by the degree of epileptic activity or help sustain ongoing epileptic activity. The identification of a common set of genes and the persistent activation of CREB signaling in human epileptic foci provide a clinically relevant set of biological markers with potential importance for developing future diagnostic and therapeutic options in human epilepsy.

The CNS pericyte response to low oxygen: early synthesis of cyclopentenone prostaglandins of the J-series.

Exposure to low oxygen induces adaptive changes at the microvascular level that are beneficial to cell survival. These adaptive changes involve complex signaling mechanisms between the vascular endothelial cell and the pericyte, and are important to the maintenance of vascular homeostasis and hemostasis. We have investigated the early response of the central nervous system (CNS) microvascular pericyte to low oxygen. In vitro exposure of primary rat CNS pericytes to low oxygen induced the rapid synthesis and release of the cyclopentenone prostaglandin (PG) PGD2 and PGJ2 within 15-30 min following hypoxic stress signal. Hypoxia-induced release of PGD2/PGJ2 was COX-1 dependent and did not involve COX-2. The exogenous addition of 15-deoxyDelta(12,14) PGJ2 to pericytes under normoxic conditions increased glut-1 protein in the absence of hypoxia. PGD2 and PGJ2 may be early signaling molecules in the pericyte stress response.