The role of AKT isoforms in glioblastoma: AKT3 delays tumor progression.

The growth factor receptor/PI3K/AKT pathway is an important drug target in many cancers including Glioblastoma. AKT, a key node in the pathway, has 3 isoforms, AKT1, AKT2 and AKT3. Here we investigate their role in GBM. We find each activated, ser473 phosphorylated isoform is present in some GBMs but expression patterns vary. There is a direct relationship between human GBM patient outcome and both AKT1 and AKT2 mRNA levels, but an inverse relationship with AKT3 mRNA. Furthermore, AKT3 mRNA levels were high in a less aggressive GBM subtype. Overexpressing AKT3 improves survival in a rodent model of GBM and decreases colony forming efficiency, but not growth rate, in glioma cells. Silencing AKT3 slows cell cycle progression in one cell line and increases apoptosis in another. Our studies of AKT3 substrates indicate (1) silencing both AKT2 and AKT3 reduces GSK3 phosphorylation (2) only AKT2 silencing reduces S6 phosphorylation. Since S6 phosphorylation is a marker of mTORC1 activity this indicates that AKT2 activates mTORC1, but AKT3 does not. Our results indicate AKT isoforms have different roles and downstream substrates in GBM. Unexpectedly, they indicate AKT3 delays tumor progression. Therefore strategies that inhibit AKT3 may be unhelpful in some GBM patients.

Laser scanning confocal endomicroscopy in the neurosurgical operating room: a review and discussion of future applications.

Laser scanning confocal endomicroscopy (LSCE) is an emerging technology for examining brain neoplasms in vivo. While great advances have been made in macroscopic fluorescence in recent years, the ability to perform confocal microscopy in vivo expands the potential of fluorescent tumor labeling, can improve intraoperative tissue diagnosis, and provides real-time guidance for tumor resection intraoperatively. In this review, the authors highlight the technical aspects of confocal endomicroscopy and fluorophores relevant to the neurosurgeon, provide a comprehensive summary of LSCE in animal and human neurosurgical studies to date, and discuss the future directions and potential for LSCE in neurosurgery.

Potential application of a handheld confocal endomicroscope imaging system using a variety of fluorophores in experimental gliomas and normal brain.

OBJECT: The authors sought to assess the feasibility of a handheld visible-wavelength confocal endomicroscope imaging system (Optiscan 5.1, Optiscan Pty., Ltd.) using a variety of rapid-acting fluorophores to provide histological information on gliomas, tumor margins, and normal brain in animal models. METHODS: Mice (n = 25) implanted with GL261 cells were used to image fluorescein sodium (FNa), 5-aminolevulinic acid (5-ALA), acridine orange (AO), acriflavine (AF), and cresyl violet (CV). A U251 glioma xenograft model in rats (n = 5) was used to image sulforhodamine 101 (SR101). A swine (n = 3) model with AO was used to identify confocal features of normal brain. Images of normal brain, obvious tumor, and peritumoral zones were collected using the handheld confocal endomicroscope. Histological samples were acquired through biopsies from matched imaging areas. Samples were visualized with a benchtop confocal microscope. Histopathological features in corresponding confocal images and photomicrographs of H & E-stained tissues were reviewed. RESULTS: Fluorescence induced by FNa, 5-ALA, AO, AF, CV, and SR101 and detected with the confocal endomicroscope allowed interpretation of histological features. Confocal endomicroscopy revealed satellite tumor cells within peritumoral tissue, a definitive tumor border, and striking fluorescent cellular and subcellular structures. Fluorescence in various tumor regions correlated with standard histology and known tissue architecture. Characteristic features of different areas of normal brain were identified as well. CONCLUSIONS: Confocal endomicroscopy provided rapid histological information precisely related to the site of microscopic imaging with imaging characteristics of cells related to the unique labeling features of the fluorophores. Although experimental with further clinical trial validation required, these data suggest that intraoperative confocal imaging can help to distinguish normal brain from tumor and tumor margin and may have application in improving intraoperative decisions during resection of brain tumors.

Label-free microscopic assessment of glioblastoma biopsy specimens prior to biobanking [corrected].

Glioblastoma is the most common primary brain tumor with a median 12- to 15-month patient survival. Improving patient survival involves better understanding the biological mechanisms of glioblastoma tumorigenesis and seeking targeted molecular therapies. Central to furthering these advances is the collection and storage of surgical biopsies (biobanking) for research. This paper addresses an imaging modality, confocal reflectance microscopy (CRM), for safely screening glioblastoma biopsy samples prior to biobanking to increase the quality of tissue provided for research and clinical trials. These data indicate that CRM can immediately identify cellularity of tissue biopsies from animal models of glioblastoma. When screening fresh human biopsy samples, CRM can differentiate a cellular glioblastoma biopsy from a necrotic biopsy without altering DNA, RNA, or protein expression of sampled tissue. These data illustrate CRM's potential for rapidly and safely screening clinical biopsy samples prior to biobanking, which demonstrates its potential as an effective screening technique that can improve the quality of tissue biobanked for patients with glioblastoma.

Determinants of major cardiovascular risk factors among participants of the South Carolina WISEWOMAN program, 2009-2012.

INTRODUCTION: Cardiovascular disease (CVD) is the leading cause of death among US women, accounting for 25% of all deaths in this population. Approximately 65% of these deaths occur in asymptomatic women. Hypertension, hypercholesterolemia, and diabetes mellitus (diabetes) are major risk factors for CVD and can be treated effectively if identified at an early stage. METHODS: Data were available from 3,572 uninsured first-time female participants aged 40 to 65 years, referred by their health professional to the South Carolina Well-Integrated Screening and Evaluation for Women Across the Nation (SC WISEWOMAN), 2009-2012. All women completed a structured health-risk and behavior questionnaire. Anthropometric measures were recorded and data on clinical risk-factors were collected. Prevalence-ratios (PRs) were obtained by predictive multivariable log-linear modeling. RESULTS: The prevalence of risk factors was 34.7% for uncontrolled hypertension, 9.3% for hypercholesterolemia, and 21% for diabetes. Prevalence of untreated hypertension was 15.6%; hypercholesterolemia, 8%; and diabetes, 4%. The greatest significant predictor of hypercholesterolemia was hypertension (PR = 4.37) and vice versa (PR = 2.39). The greatest significant predictors of diabetes were obesity (PR = 2.23), family history of diabetes (PR = 2.02), and hypercholesterolemia (PR = 1.85). Being obese (PR = 1.36), overweight (PR = 1.23), aged 60 years or more (PR = 1.26), and black (PR = 1.14) were significant predictors of having at least one CVD risk factor. Being black (PR = 1.09) was the only significant predictor of having comorbid conditions. CONCLUSION: Prevalence of uncontrolled CVD risk factors was high among participants in the SC WISEWOMAN program. These findings confirm that the program is reaching high-risk women who are in need of interventions to reduce their risk for CVD through lifestyle changes.

Nanoliposomes protect against AL amyloid light chain protein-induced endothelial injury.

CONTEXT: A newly-recognized pathogenic mechanism underlying light chain amyloidosis (AL) involves endothelial dysfunction and cell injury caused by misfolded light chain proteins (LC). Nanoliposomes (NL) are artificial phospholipid vesicles that could attach to misfolded proteins and reduce tissue injury. OBJECTIVE: To test whether co-treatment with NL reduces LC-induced endothelial dysfunction and cell death. METHODS: Abdominal subcutaneous adipose arterioles from 14 non-AL subjects were cannulated; dilator response to acetylcholine and papaverine were measured at baseline and following 1-hour exposure to LC (20 µg/mL, 2 purified from AL subjects' urine, 1 from human recombinant LC [AL-09]) ± NL (phosphatidylcholine/cholesterol/phosphatidic acid 70/25/5 molar ratio) or NL alone. Human aortic artery endothelial cells (HAEC) were exposed to Oregon Green-labeled LC ± NL for 24 hours and intracellular LC and apoptosis (Hoechst stain) were measured. Circular dichroism spectroscopy was performed on AL-09 LC ± NL to follow changes in secondary structure and protein thermal stability. RESULTS: LC caused impaired dilation to acetylcholine that was restored by NL (control - 94.0 ± 1.8%, LC - 65.0 ± 7.1%, LC + NL - 95.3 ± 1.8%, p ≤ 0.001 LC versus control or LC + NL). NL protection was inhibited by L-NG-nitroarginine methyl ester. NL increased the beta sheet structure of LC, reduced endothelial cell internalization of LC and protected against LC-induced endothelial cell death. CONCLUSIONS: LC induced human adipose arteriole endothelial dysfunction and endothelial cell death, which were reversed by co-treatment with NL. This protection may partly be due to enhancing LC protein structure and reducing LC internalization. Nanoliposomes represent a promising new class of agents to ameliorate tissue injury from protein misfolding diseases such as AL.

Locoregional delivery of IL-13Rα2-targeting CAR-T cells in recurrent high-grade glioma: a phase 1 trial.

Chimeric antigen receptor T cell (CAR-T) therapy is an emerging strategy to improve treatment outcomes for recurrent high-grade glioma, a cancer that responds poorly to current therapies. Here we report a completed phase I trial evaluating IL-13Rα2-targeted CAR-T cells in 65 patients with recurrent high-grade glioma, the majority being recurrent glioblastoma (rGBM). Primary objectives were safety and feasibility, maximum tolerated dose/maximum feasible dose and a recommended phase 2 dose plan. Secondary objectives included overall survival, disease response, cytokine dynamics and tumor immune contexture biomarkers. This trial evolved to evaluate three routes of locoregional T cell administration (intratumoral (ICT), intraventricular (ICV) and dual ICT/ICV) and two manufacturing platforms, culminating in arm 5, which utilized dual ICT/ICV delivery and an optimized manufacturing process. Locoregional CAR-T cell administration was feasible and well tolerated, and as there were no dose-limiting toxicities across all arms, a maximum tolerated dose was not determined. Probable treatment-related grade 3+ toxicities were one grade 3 encephalopathy and one grade 3 ataxia. A clinical maximum feasible dose of 200 × 106 CAR-T cells per infusion cycle was achieved for arm 5; however, other arms either did not test or achieve this dose due to manufacturing feasibility. A recommended phase 2 dose will be refined in future studies based on data from this trial. Stable disease or better was achieved in 50% (29/58) of patients, with two partial responses, one complete response and a second complete response after additional CAR-T cycles off protocol. For rGBM, median overall survival for all patients was 7.7 months and for arm 5 was 10.2 months. Central nervous system increases in inflammatory cytokines, including IFNγ, CXCL9 and CXCL10, were associated with CAR-T cell administration and bioactivity. Pretreatment intratumoral CD3 T cell levels were positively associated with survival. These findings demonstrate that locoregional IL-13Rα2-targeted CAR-T therapy is safe with promising clinical activity in a subset of patients. ClinicalTrials.gov Identifier: NCT02208362 .

Toxicity, biodistribution, and ex vivo MRI detection of intravenously injected cationized ferritin.

The goal of the work was to establish the toxicity and biodistribution of the superparamagnetic protein cationized ferritin (CF) after intravenous injection. Intravenously injected CF has been used to target the extracellular matrix with high specificity in the kidney glomerulus, allowing measurements of individual glomeruli using T2*-weighted MRI. For the routine use of CF as an extracellular matrix-specific tracer, it is important to determine whether CF is toxic. In this work, we investigated the renal and hepatic toxicity, leukocyte count, and clearance of intravenously injected CF. Furthermore, we studied CF labeling in several organs using MRI and immunohistochemistry. Serum measurements of biomarkers suggest that intravenous injection of CF is neither nephrotoxic nor hepatotoxic and does not increase leukocyte counts in healthy rats at a dose of 5.75 mg/100 g. In addition to known glomerular labeling, confocal and MRI suggest that intravenously injected CF labels the extracellular matrix of the hepatic sinusoid, extracellular glycocalyx of alveolar endothelial cells, and macrophages in the spleen. Liver T2* values suggest that CF is cleared by 7 days after injection. These results suggest that CF may serve as a useful contrast agent for detection of a number of structures and functions with minimal toxicity.

Cationized ferritin as a magnetic resonance imaging probe to detect microstructural changes in a rat model of non-alcoholic steatohepatitis.

PURPOSE: The goal of this work was to detect disease-related microstructural changes to the liver using magnetic resonance imaging. Chronic liver disease can cause microstructural changes in the liver that reduce plasma access to the perisinusoidal space--the site of exchange between the blood plasma and the hepatic parenchyma. The reduced plasma access to the perisinusoidal space inhibits hepatic function and contributes to the ∼30,000 chronic liver disease-related deaths per year. METHODS: The extracellular matrix-specific cationized ferritin magnetic resonance imaging probe was injected intravenously into healthy rats and a rat model of the chronic liver disease non-alcoholic steatohepatitis. Rats were subsequently imaged with T2*-weighted magnetic resonance imaging. RESULTS: This work demonstrates that the binding of cationized ferritin to the perisinusoidal extracellular matrix is reduced by 55% in a rat model of non-alcoholic steatohepatitis compared to healthy controls. This reduced binding is detectable in vivo with magnetic resonance imaging. Immunofluorescence and electron microscopy indicated that the reduced binding is due to inhibited macromolecular access to the perisinusoidal space caused by non-alcoholic steatohepatitis-related microstructural changes. CONCLUSIONS: The reduced accumulation of intravenously injected cationized ferritin may report on changes in macromolecular access to the liver parenchyma in chronic liver disease.

Expansion of endogenous T cells in CSF of pediatric CNS tumor patients undergoing locoregional delivery of IL13R〿2-targeting CAR T cells: an interim analysis.

Outcomes for pediatric brain tumor patients remain poor, and there is optimism that chimeric antigen receptor (CAR) T cell therapy can improve prognosis. Here, we present interim results from the first six pediatric patients treated on an ongoing phase I clinical trial (NCT04510051) of IL13BBζ-CAR T cells delivered weekly into the lateral cerebral ventricles, identifying clonal expansion of endogenous CAR-negative CD8+ T cells in the cerebrospinal fluid (CSF) over time. Additionally, of the five patients evaluable for disease response, three experienced transient radiographic and/or clinical benefit not meeting protocol criteria for response. The first three patients received CAR T cells alone; later patients received lymphodepletion before the first infusion. There were no dose limiting toxicities (DLTs). Aside from expected cytopenias in patients receiving lymphodepletion, serious adverse events possibly attributed to CAR T cell infusion were limited to one episode of headache and one of liver enzyme elevation. One patient withdrew from treatment during the DLT period due to a Grade 3 catheter-related infection and was not evaluable for disease response, although this was not attributed to CAR T cell infusion. Importantly, scRNA- and scTCR-sequence analyses provided insights into CAR T cell interaction with the endogenous immune system. In particular, clonally expanded endogenous CAR- T cells were recovered from the CSF, but not the peripheral blood, of patients who received intraventricular IL13BBζ-CAR T cell therapy. Additionally, although immune infiltrates in CSF and post-therapy tumor did not generally correlate, a fraction of expanded T cell receptors (TCRs) was seen to overlap between CSF and tumor. This has important implications for what samples are collected on these trials and how they are analyzed. These initial findings provide support for continued investigation into locoregionally-delivered IL13BBζ-CAR T cells for children with brain tumors.

Subtemporal Transcollateral Sulcus Approach for Temporal Horn Tumors: 2-Dimensional Operative Video and Description of the Technique.

INTRODUCTION: Purely temporal intraventricular tumors are uncommon. Given their deep location, access to these brain tumors can be challenging in terms of preserving brain tissue. The subtemporal approach spares the lateral temporal cortex and is a less traumatic corridor to reach intraventricular temporal tumors. OBJECTIVE: To describe and assess the feasibility of the subtemporal transcollateral approach for the removal of a temporal horn tumor. METHODS: We describe the subtemporal transcollateral sulcus operative technique detailed step-by-step and depicted through both video and illustrations to surgically resect a left intraventricular temporal mass in a 44-year-old woman who presented with worsening memory deficits. The surgery was performed under general anesthesia and with the use of a microscope and neuronavigation. RESULTS: The patient did not suffer from any postoperative complications. Her vision was intact, and her memory deficit was unchanged. A brain MRI showed complete removal of the tumor. The pathological examination revealed a World Health Organization grade I meningioma. CONCLUSION: The subtemporal transsulcal approach seems to be an efficient and safe way to access intraventricular lesions within the temporal horn while avoiding any disruption of the optic radiations and temporal language areas.

Molecular Imaging of Glucose Metabolism for Intraoperative Fluorescence Guidance During Glioma Surgery.

PURPOSE: This study evaluated the use of molecular imaging of fluorescent glucose analog 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG) as a discriminatory marker for intraoperative tumor border identification in a murine glioma model. PROCEDURES: 2-NBDG was assessed in GL261 and U251 orthotopic tumor-bearing mice. Intraoperative fluorescence of topical and intravenous 2-NBDG in normal and tumor regions was assessed with an operating microscope, handheld confocal laser scanning endomicroscope (CLE), and benchtop confocal laser scanning microscope (LSM). Additionally, 2-NBDG fluorescence in tumors was compared with 5-aminolevulinic acid-induced protoporphyrin IX fluorescence. RESULTS: Intravenously administered 2-NBDG was detectable in brain tumor and absent in contralateral normal brain parenchyma on wide-field operating microscope imaging. Intraoperative and benchtop CLE showed preferential 2-NBDG accumulation in the cytoplasm of glioma cells (mean [SD] tumor-to-background ratio of 2.76 [0.43]). Topically administered 2-NBDG did not create sufficient tumor-background contrast for wide-field operating microscope imaging or under benchtop LSM (mean [SD] tumor-to-background ratio 1.42 [0.72]). However, topical 2-NBDG did create sufficient contrast to evaluate cellular tissue architecture and differentiate tumor cells from normal brain parenchyma. Protoporphyrin IX imaging resulted in a more specific delineation of gross tumor margins than intravenous or topical 2-NBDG and a significantly higher tumor-to-normal-brain fluorescence intensity ratio. CONCLUSION: After intravenous administration, 2-NBDG selectively accumulated in the experimental brain tumors and provided bright contrast under wide-field fluorescence imaging with a clinical-grade operating microscope. Topical 2-NBDG was able to create a sufficient contrast to differentiate tumor from normal brain cells on the basis of visualization of cellular architecture with CLE. 5-Aminolevulinic acid demonstrated superior specificity in outlining tumor margins and significantly higher tumor background contrast. Given the nontoxicity of 2-NBDG, its use as a topical molecular marker for noninvasive in vivo intraoperative microscopy is encouraging and warrants further clinical evaluation.

Cerebellar infarction requiring surgical decompression in patient with COVID 19 pathological analysis and brief review.

BACKGROUND: This report and literature review describes a case of a COVID-19 patient who suffered a cerebellar stroke requiring neurosurgical decompression. This is the first reported case of a sub-occipital craniectomy with brain biopsy in a COVID-19 patient showing leptomeningeal venous intimal inflammation. CLINICAL DESCRIPTION: The patient is a 48-year-old SARS-COV-2 positive male with multiple comorbidities, who presented with fevers and respiratory symptoms, and imaging consistent with multifocal pneumonia. On day 5 of admission, the patient had sudden change in mental status, increased C-Reactive Protein, ferritin and elevated Interleukin-6 levels. Head CT showed cerebral infarction from vertebral artery occlusion. Given subsequent rapid neurologic decline from cerebellar swelling and mass effect on his brainstem emergent neurosurgical intervention was performed. Brain biopsy found a vein with small organizing thrombus adjacent to focally proliferative intima with focal intimal neutrophils. CONCLUSION: A young man with COVID-19 and suspected immune dysregulation, complicated by a large cerebrovascular ischemic stroke secondary to vertebral artery thrombosis requiring emergent neurosurgical intervention for decompression with improved neurological outcomes. Brain biopsy was suggestive of inflammation from thrombosed vessel, and neutrophilic infiltration of cerebellar tissue.

Provision of rapid and specific ex vivo diagnosis of central nervous system lymphoma from rodent xenograft biopsies by a fluorescent aptamer.

OBJECTIVE: Differentiating central nervous system (CNS) lymphoma from other intracranial malignancies remains a clinical challenge in surgical neuro-oncology. Advances in clinical fluorescence imaging contrast agents and devices may mitigate this challenge. Aptamers are a class of nanomolecules engineered to bind cellular targets with antibody-like specificity in a fraction of the staining time. Here, the authors determine if immediate ex vivo fluorescence imaging with a lymphoma-specific aptamer can rapidly and specifically diagnose xenografted orthotopic human CNS lymphoma at the time of biopsy. METHODS: The authors synthesized a fluorescent CNS lymphoma-specific aptamer by conjugating a lymphoma-specific aptamer with Alexa Fluor 488 (TD05-488). They modified human U251 glioma cells and Ramos lymphoma cells with a lentivirus for constitutive expression of red fluorescent protein and implanted them intracranially into athymic nude mice. Three to 4 weeks postimplantation, acute slices (biopsies, n = 28) from the xenografts were collected, placed in aptamer solution, and imaged with a Zeiss fluorescence microscope. Three aptamer staining concentrations (0.3, 1.0, and 3.0 µM) and three staining times (5, 10, and 20 minutes) followed by a 1-minute wash were tested. A file of randomly selected images was distributed to neurosurgeons and neuropathologists, and their ability to distinguish CNS lymphoma from negative controls was assessed. RESULTS: The three staining times and concentrations of TD05-488 were tested to determine the diagnostic accuracy of CNS lymphoma within a frozen section time frame. An 11-minute staining protocol with 1.0-µM TD05-488 was most efficient, labeling 77% of positive control lymphoma cells and less than 1% of negative control glioma cells (p < 0.001). This protocol permitted clinicians to positively identify all positive control lymphoma images without misdiagnosing negative control images from astrocytoma and normal brain. CONCLUSIONS: Ex vivo fluorescence imaging is an emerging technique for generating rapid histopathological diagnoses. Ex vivo imaging with a novel aptamer-based fluorescent nanomolecule could provide an intraoperative tumor-specific diagnosis of CNS lymphoma within 11 minutes of biopsy. Neurosurgeons and neuropathologists interpreted images generated with this molecular probe with high sensitivity and specificity. Clinical application of TD05-488 may permit specific intraoperative diagnosis of CNS lymphoma in a fraction of the time required for antibody staining.

Evaluation of Diagnostic Accuracy Following the Coadministration of Delta-Aminolevulinic Acid and Second Window Indocyanine Green in Rodent and Human Glioblastomas.

PURPOSE: Fluorescence-guided-surgery offers intraoperative visualization of neoplastic tissue. Delta-aminolevulinic acid (5-ALA), which targets enzymatic abnormality in neoplastic cells, is the only approved agent for fluorescence-guided neurosurgery. More recently, we described Second Window Indocyanine Green (SWIG) which targets neoplastic tissue through enhanced vascular permeability. We hypothesized that SWIG would demonstrate similar clinical utility in identification of high-grade gliomas compared with 5-ALA. PROCEDURES: Female C57/BL6 and nude/athymic mice underwent intracranial implantation of 300,000 GL261 and U87 cells, respectively. Tumor-bearing mice were euthanized after administration of 5-ALA (200 mg/kg intraperitoneal) and SWIG (5 mg/kg intravenous). Brain sections were imaged for protoporphyrin-IX and ICG fluorescence. Fluorescence and H&E images were registered using semi-automatic scripts for analysis. Human subjects with HGG were administered SWIG (2.5 mg/kg intravenous) and 5-ALA (20 mg/kg oral). Intraoperatively, tumors were imaged for ICG and protoporphyrin-IX fluorescence. RESULTS: In non-necrotic tumors, 5-ALA and SWIG demonstrated 90.2 % and 89.2 % tumor accuracy (p value = 0.52) in U87 tumors and 88.1 % and 87.7 % accuracy (p value = 0.83) in GL261 tumors. The most distinct difference between 5-ALA and SWIG distribution was seen in areas of tumor-associated necrosis, which often showed weak/no protoporphyrin-IX fluorescence, but strong SWIG fluorescence. In twenty biopsy specimens from four subjects with HGG, SWIG demonstrated 100 % accuracy, while 5-ALA demonstrated 75-85 % accuracy; there was 90 % concordance between SWIG and 5-ALA fluorescence. CONCLUSION: Our results provide the first direct comparison of the diagnostic utility of SWIG vs 5-ALA in both rodent and human HGG. Given the broader clinical utility of SWIG compared with 5-ALA, our data supports the use of SWIG in tumor surgery to improve the extent of safe resections. CLINICAL TRIAL: NCT02710240 (US National Library of Medicine Registry; https://www.clinicaltrials.gov/ct2/show/NCT02710240?id=NCT02710240&draw=2&rank=1 ).

Pediatric spinal cord biopsy: A case series from a high-volume referral center.

Pediatric patients presenting with intramedullary spinal cord lesions often require specific diagnoses to guide their treatment plans. Though results from magnetic resonance imaging and lumbar puncture may narrow the differential diagnosis, these tests cannot always provide a definitive diagnosis. In such cases, spinal cord biopsy may be undertaken to provide a specific histopathologic diagnosis for guiding treatment. Data from the adult population show 24% of spinal cord biopsies can be nondiagnostic and the procedure may carry a 21% complication rate. Therefore, spinal cord biopsy may portend a similar high risk-to-benefit ratio in the pediatric population. Here, we review spinal cord biopsy cases scheduled for diagnosis, and not debulking, at a high volume pediatric referral center during a seventeen-year period. We report our experience with five patients who met our inclusion criteria. Due to the rarity of the procedure, statistically significant factors associated with improved diagnostic yield or peri-operative complication could not be identified. A definitive diagnosis which guided the post-operative treatment plan was obtained in four of our five patients. None of our patients developed post-operative motor deficits. However, these patients were susceptible to the same risks of open spine surgery, such as wound infections and spinal deformities. Our case series shows that intramedullary spinal cord biopsies may provide tissue for obtaining histopatholgic diagnoses. However, the potential risks of complication, and the possibility of obtaining nondiagnostic tissue, should be discussed with patients, families and their medical treatment teams.

Neurosurgical Flexible Probe Microscopy with Enhanced Architectural and Cytological Detail.

BACKGROUND: Microscopic delineation and clearance of tumor cells at neurosurgical excision margins potentially reduce tumor recurrence and increase patient survival. Probe-based in vivo fluorescence microscopy technologies are promising for neurosurgical in vivo microscopy. OBJECTIVE: We sought to demonstrate a flexible fiberoptic epifluorescence microscope capable of enhanced architectural and cytological imaging for in vivo microscopy during neurosurgical procedures. METHODS: Eighteen specimens were procured from neurosurgical procedures. These specimens were stained with acridine orange and imaged with a 3-dimensional (3D)-printed epifluorescent microscope that incorporates a flexible fiberoptic probe. Still images and video sequence frames were processed using frame alignment, signal projection, and pseudo-coloring, resulting in resolution enhancement and an increased field of view. RESULTS: Images produced displayed good nuclear contrast and architectural detail. Grade 1 meningiomas demonstrated 3D chords and whorls. Low-grade meningothelial nuclei showed streaming and displayed regularity in size, shape, and distribution. Oligodendrogliomas showed regular round nuclei and a variably staining background. Glioblastomas showed high degrees of nuclear pleomorphism and disarray. Mitoses, vascular proliferation, and necrosis were evident. CONCLUSIONS: We demonstrate the utility of a 3D-printed, flexible probe microscope for high-resolution microscopic imaging with increased architectural detail. Enhanced in vivo imaging using this device may improve our ability to detect and decrease microscopic tumor burden at excision margins during neurosurgical procedures.

Fluorescence-guided stereotactic biopsy: a proof-of-concept study.

OBJECTIVEAccurate histopathological diagnoses are often necessary for treating neuro-oncology patients. However, stereotactic biopsy (STB), a common method for obtaining suspicious tissue from deep or eloquent brain regions, fails to yield diagnostic tissue in some cases. Failure to obtain diagnostic tissue can delay initiation of treatment and may result in further invasive procedures for patients. In this study, the authors sought to determine if the coupling of in vivo optical imaging with an STB system is an effective method for identification of diagnostic tissue at the time of biopsy.METHODSA minimally invasive fiber optic imaging system was developed by coupling a 0.65-mm-diameter coherent fiber optic fluorescence microendoscope to an STB system. Human U251 glioma cells were transduced for stable expression of blue fluorescent protein (BFP) to produce U251-BFP cells that were utilized for in vitro and in vivo experiments. In vitro, blue fluorescence was confirmed, and tumor cell delineation by fluorescein sodium (FNa) was quantified with fluorescence microscopy. In vivo, transgenic athymic rats implanted with U251-BFP cells (n = 4) were utilized for experiments. Five weeks postimplantation, the rats received 5-10 mg/kg intravenous FNa and underwent craniotomies overlying the tumor implantation site and contralateral normal brain. A clinical STB needle containing our 0.65-mm imaging fiber was passed through each craniotomy and images were collected. Fluorescence images from regions of interest ipsilateral and contralateral to tumor implantation were obtained and quantified.RESULTSLive-cell fluorescence imaging confirmed blue fluorescence from transduced tumor cells and revealed a strong correlation between tumor cells quantified by blue fluorescence and FNa contrast (R2 = 0.91, p < 0.001). Normalized to background, in vivo FNa-mediated fluorescence intensity was significantly greater from tumor regions, verified by blue fluorescence, compared to contralateral brain in all animals (301.7 ± 34.18 relative fluorescence units, p < 0.001). Fluorescence intensity measured from the tumor margin was not significantly greater than that from normal brain (p = 0.89). Biopsies obtained from regions of strong fluorescein contrast were histologically consistent with tumor.CONCLUSIONSThe authors found that in vivo fluorescence imaging with an STB needle containing a submillimeter-diameter fiber optic fluorescence microendoscope provided direct visualization of neoplastic tissue in an animal brain tumor model prior to biopsy. These results were confirmed in vivo with positive control cells and by post hoc histological assessment. In vivo fluorescence guidance may improve the diagnostic yield of stereotactic biopsies.

Epithelioid glioblastoma presenting as aphasia in a young adult with ovarian cancer: A case report.

Our patient's clinical history and preoperative radiographic evaluation suggested central nervous system (CNS) metastatic disease. Ultimately, final pathology revealed epithelioid glioblastoma (eGBM), a newly classified CNS primary tumor. This reinforces the importance of direct tissue sampling and including eGBM on the differential for young patients with histories of systemic cancer presenting with new CNS lesions.

Delta-Aminolevulinic Acid-Mediated Photodiagnoses in Surgical Oncology: A Historical Review of Clinical Trials.

Fluorescence imaging is an emerging clinical technique for real-time intraoperative visualization of tumors and their boundaries. Though multiple fluorescent contrast agents are available in the basic sciences, few fluorescence agents are available for clinical use. Of the clinical fluorophores, delta aminolevulinic acid (5ALA) is unique for generating visible wavelength tumor-specific fluorescence. In 2017, 5ALA was FDA-approved for glioma surgery in the United States. Additionally, clinical studies suggest this agent may have utility in surgical subspecialties outside of neurosurgery. Data from dermatology, OB/GYN, urology, cardiothoracic surgery, and gastrointestinal surgery show 5ALA is helpful for intraoperative visualization of malignant tissues in multiple organ systems. This review summarizes data from English-language 5ALA clinical trials across surgical subspecialties. Imaging systems, routes of administration, dosing, efficacy, and related side effects are reviewed. We found that modified surgical microscopes and endoscopes are the preferred imaging devices. Systemic dosing across surgical specialties range between 5 and 30 mg/kg bodyweight. Multiple studies discussed potential for skin irritation with sun exposure, however this side effect is infrequently reported. Overall, 5ALA has shown high sensitivity for labeling malignant tissues and providing a means to visualize malignant tissue not apparent with standard operative light sources.