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Purpose:Liquid biopsy offers a minimally invasive tool to diagnose and monitor the heterogeneous molecular landscape of tumors over time and therapy. Detection of TERT promoter mutations (C228T, C250T) in cfDNA has been successful for some systemic cancers but has yet to be demonstrated in gliomas, despite the high prevalence of these mutations in glioma tissue (>60% of all tumors).Experimental Design:Here, we developed a novel digital droplet PCR (ddPCR) assay that incorporates features to improve sensitivity and allows for the simultaneous detection and longitudinal monitoring of two TERT promoter mutations (C228T and C250T) in cfDNA from the plasma of patients with glioma.Results:In baseline performance in tumor tissue, the assay had perfect concordance with an independently performed clinical pathology laboratory assessment of TERT promoter mutations in the same tumor samples [95% confidence interval (CI), 94%–100%]. Extending to matched plasma samples, we detected TERT mutations in both discovery and blinded multi-institution validation cohorts with an overall sensitivity of 62.5% (95% CI, 52%–73%) and a specificity of 90% (95% CI, 80%–96%) compared with the gold-standard tumor tissue–based detection of TERT mutations. Upon longitudinal monitoring in 5 patients, we report that peripheral TERT-mutant allele frequency reflects the clinical course of the disease, with levels decreasing after surgical intervention and therapy and increasing with tumor progression.Conclusions:Our results demonstrate the feasibility of detecting circulating cfDNA TERT promoter mutations in patients with glioma with clinically relevant sensitivity and specificity.

Supplementary File Figure legends

Supplementary Figure 4. Correlations between (a) progression free survival, (b) overall survival, (c) tumor grade, (d) contrast enhancement, (e) type of TERT mutation, (f) tumor volume, (g) duration of disease, (h) age. Contingency tables are provided for (i) Discovery Sample Set 1 (j) Discovery Sample Set 2 (k) MultiInstitution Validation Cohort (l) Overall Combined Cohort. (m) 4 replicates of 4 uL of cfDNA from matched CSF samples (n=4; n=3 TERT mutant and n=1 WT) was used as input for absolute quantification of TERT mutant and wildtype copies. MAF is calculated using the formula described in Methods. Copies/mL for plasma samples are plotted against Study ID, classified by SNapSHOT/Pathology as floating bars, with line at the mean copies/mL. (n) Contingency table for matched CSF plasma.

Compared to adult AVMs, there is a paucity of data on the microsurgical treatment of pediatric AVMs. We report our institutional experience with pediatric AVMs treated by microsurgical resection with or without endovascular embolization and radiation therapy. We retrospectively reviewed all patients ≤ 18 years of age with cerebral AVMs that underwent microsurgical resection at Rady Children’s Hospital 2002–2019. Eighty-nine patients met inclusion criteria. The mean age was 10.3 ± 5.0 years, and 56% of patients were male. In total, 72 (81%) patients presented with rupture. Patients with unruptured AVMs presented with headache (n = 5, 29.4%), seizure (n = 9, 52.9%), or incidental finding (n = 3, 17.7%). The mean presenting mRS was 2.8 ± 1.8. AVM location was lobar in 78%, cerebellar/brainstem in 15%, and deep supratentorial in 8%. Spetzler-Martin grade was I in 28%, II in 45%, III in 20%, IV in 6%, and V in 1%. Preoperative embolization was utilized in 38% of patients and more frequently in unruptured than ruptured AVMs (62% vs. 32%, p = 0.022). Radiographic obliteration was achieved in 76/89 (85.4%) patients. Complications occurred in 7 (8%) patients. Annualized rates of delayed rebleeding and recurrence were 1.2% and 0.9%, respectively. The mean follow-up was 2.8 ± 3.1 years. A good neurological outcome (mRS score ≤ 2) was obtained in 80.9% of patients at last follow-up and was improved relative to presentation for 75% of patients. Our case series demonstrates high rates of radiographic obliteration and relatively low incidence of neurologic complications of treatment or AVM recurrence.

OBJECTIVE The aim of this study was to evaluate the association between zip code–level socioeconomic status (SES) and presenting characteristics and short-term clinical outcomes in patients with nonfunctioning pituitary adenoma (NFPA). METHODS A retrospective review of prospectively collected data from the University of Southern California Pituitary Center was conducted to identify all patients undergoing surgery for pituitary adenoma (PA) from 2000 to 2021 and included all patients with NFPA with recorded zip codes at the time of surgery. A normalized socioeconomic metric by zip code was then constructed using data from the American Community Survey estimates, which was categorized into tertiles. Multiple imputation was used for missing data, and multivariable linear and logistic regression models were constructed to estimate mean differences and multivariable-adjusted odds ratios for the association between zip code–level SES and presenting characteristics and outcomes. RESULTS A total of 637 patients were included in the overall analysis. Compared with patients in the lowest SES tertile, those in the highest tertile were more likely to be treated at a private (rather than safety net) hospital, and were less likely to present with headache, vision loss, and apoplexy. After multivariable adjustment for age, sex, and prior surgery, SES in the highest compared with lowest tertile was inversely associated with tumor size at diagnosis (−4.9 mm, 95% CI −7.2 to −2.6 mm, p < 0.001) and was positively associated with incidental diagnosis (multivariable-adjusted OR 1.72, 95% CI 1.02–2.91). Adjustment for hospital (private vs safety net) attenuated the observed associations, but disparities by SES remained statistically significant for tumor size. Despite substantial differences at presentation, there were no significant differences in length of stay or odds of an uncomplicated procedure by zip code–level SES. Patients from lower-SES zip codes were more likely to require postoperative steroid replacement and less likely to achieve gross-total resection. CONCLUSIONS In this series, lower zip code–level SES was associated with more severe disease at the time of diagnosis for NFPA patients, including larger tumor size and lower rates of incidental diagnosis. Despite these differences at presentation, no significant differences were observed in short-term postoperative complications, although patients with higher zip code–level SES had higher rates of gross-total resection.

OBJECTS Cushing's disease (CD) is the most common cause of ACTH-dependent hypercortisolism in children age ≥ 7. The utility of bilateral inferior petrosal sinus sampling (BIPSS), an important test in adults, is less defined in children. We present a case series of children with ACTH-dependent hypercortisolemia and review the literature to assess the utility of BIPSS in the diagnosis and localization of CD. METHODS We performed an IRB-approved chart review of patients aged ≤ 18 with ACTH-dependent hypercortisolism at MGH between 2000 and 2019 and collected clinical, laboratory, radiographic, BIPSS, surgical, and outcomes data. RESULTS In our cohort (n = 21), BIPSS had a sensitivity of 93% and specificity of 100% for diagnosis of CD. Compared to surgery, successful BIPSS correctly predicted adenoma laterality in 69% of cases vs. 70% by MRI. Among patients with lesions ≥ 4 mm (n = 9), BIPSS correctly lateralized in 50% vs. 100% by MRI. In patients with subtle lesions (

Simple Summary The BRAF V600E mutation has been identified as a key driver in brain tumors and brain tumor metastasis. The ability to detect this mutation in a minimally invasive plasma assay offers advantages over traditional tissue-based biopsy for the disease diagnosis and monitoring. The aim of this study was to develop an assay for the detection of BRAF V600E in the plasma of patients with brain tumors and brain tumor metastasis. We demonstrate BRAF V600E detection using a novel plasma-based ddPCR assay. We detect the mutation in circulating nucleic acids in 4/5 patients with mutant gliomas and metastatic melanoma. We also show correlation between plasma BRAF V600E and clinical status. This proof of principle study is important in the context of application of liquid biopsy in plasma to the neuro-oncologic field. The assay may be useful as a diagnostic adjunct, prognostication tool, and method for monitoring of disease and treatment response. Abstract Liquid biopsy provides a minimally invasive platform for the detection of tumor-derived information, including hotspot mutations, such as BRAF V600E. In this study, we provide evidence of the technical development of a ddPCR assay for the detection of BRAF V600E mutations in the plasma of patients with glioma or brain metastasis. In a small patient cohort (n = 9, n = 5 BRAF V600E, n = 4 BRAF WT, n = 4 healthy control), we were able to detect the BRAF V600E mutation in the plasma of 4/5 patients with BRAF V600E-tissue confirmed mutant tumors, and none of the BRAF WT tumors. We also provide evidence in two metastatic patients with longitudinal monitoring, where the plasma-based BRAF V600E mutation correlated with clinical disease status. This proof of principle study demonstrates the potential of this assay to serve as an adjunctive tool for the detection, monitoring, and molecular characterization of BRAF mutant gliomas and brain metastasis.

Purpose: Liquid biopsy offers a minimally invasive tool to diagnose and monitor the heterogeneous molecular landscape of tumors over time and therapy. Detection of TERT promoter mutations (C228T, C250T) in cfDNA has been successful for some systemic cancers but has yet to be demonstrated in gliomas, despite the high prevalence of these mutations in glioma tissue (>60% of all tumors). Experimental Design: Here, we developed a novel digital droplet PCR (ddPCR) assay that incorporates features to improve sensitivity and allows for the simultaneous detection and longitudinal monitoring of two TERT promoter mutations (C228T and C250T) in cfDNA from the plasma of patients with glioma. Results: In baseline performance in tumor tissue, the assay had perfect concordance with an independently performed clinical pathology laboratory assessment of TERT promoter mutations in the same tumor samples [95% confidence interval (CI), 94%–100%]. Extending to matched plasma samples, we detected TERT mutations in both discovery and blinded multi-institution validation cohorts with an overall sensitivity of 62.5% (95% CI, 52%–73%) and a specificity of 90% (95% CI, 80%–96%) compared with the gold-standard tumor tissue–based detection of TERT mutations. Upon longitudinal monitoring in 5 patients, we report that peripheral TERT-mutant allele frequency reflects the clinical course of the disease, with levels decreasing after surgical intervention and therapy and increasing with tumor progression. Conclusions: Our results demonstrate the feasibility of detecting circulating cfDNA TERT promoter mutations in patients with glioma with clinically relevant sensitivity and specificity.

Liquid biopsy offers a minimally invasive tool to diagnose and monitor the heterogeneous molecular landscape of tumors over time and therapy. Gliomas have been challenging to sample with blood-based liquid biopsy due to low levels of circulating tumor-derived nucleic acid, and prior efforts have shown specific point mutations in less than 5% of glioma patients. Detection of TERT promoter mutations (C228T, C250T) in cfDNA has been successful for some systemic cancers but has yet to be demonstrated in gliomas, despite the high prevalence of these mutations in glioma tissue (>60% of all tumors). Here, we developed a novel digital droplet PCR (ddPCR) assay, that incorporates features to improve sensitivity and allows for the simultaneous detection and longitudinal monitoring of two TERT promoter mutations (C228T and C250T) in cfDNA from the plasma of glioma patients. In baseline performance in tumor tissue, (n = 157 samples), the assay had perfect concordance with an independently performed clinical pathology laboratory assessment of TERT promoter mutations in the same tumor samples (95% CI 94%-100%). Extending to matched plasma samples, we detected TERT mutations in both discovery and blinded multi-institution validation cohorts with an overall sensitivity of 62.5% (95% CI 52%-73%) and a specificity of 90% (95% CI 80%-96%) compared to the gold standard tumor tissue-based detection of TERT mutations. Upon longitudinal monitoring in 5 patients, we report that peripheral TERT mutant allele frequency reflects the clinical course of the disease with levels decreasing after surgical intervention and therapy and increasing with tumor progression. Our results demonstrate the feasibility of detecting circulating cfDNA TERT promoter mutations in glioma patients with clinically relevant sensitivity and specificity using a novel, enhanced ddPCR approach. The functionality of this assay also suggests a new clinical role for plasma-based cfDNA analysis to complement tissue-based histopathologic and molecular characterization for diagnosis and spatiotemporal monitoring of brain tumors.

Compared to adult AVMs, there is a paucity of data on the microsurgical treatment of pediatric AVMs. We report our institutional experience with pediatric AVMs treated by microsurgical resection with or without endovascular embolization and radiation therapy.We retrospectively reviewed all patients ≤ 18 years of age with cerebral AVMs that underwent microsurgical resection at Rady Children's Hospital 2002-2019.Eighty-nine patients met inclusion criteria. The mean age was 10.3 ± 5.0 years, and 56% of patients were male. In total, 72 (81%) patients presented with rupture. Patients with unruptured AVMs presented with headache (n = 5, 29.4%), seizure (n = 9, 52.9%), or incidental finding (n = 3, 17.7%). The mean presenting mRS was 2.8 ± 1.8. AVM location was lobar in 78%, cerebellar/brainstem in 15%, and deep supratentorial in 8%. Spetzler-Martin grade was I in 28%, II in 45%, III in 20%, IV in 6%, and V in 1%. Preoperative embolization was utilized in 38% of patients and more frequently in unruptured than ruptured AVMs (62% vs. 32%, p = 0.022). Radiographic obliteration was achieved in 76/89 (85.4%) patients. Complications occurred in 7 (8%) patients. Annualized rates of delayed rebleeding and recurrence were 1.2% and 0.9%, respectively. The mean follow-up was 2.8 ± 3.1 years. A good neurological outcome (mRS score ≤ 2) was obtained in 80.9% of patients at last follow-up and was improved relative to presentation for 75% of patients.Our case series demonstrates high rates of radiographic obliteration and relatively low incidence of neurologic complications of treatment or AVM recurrence.

Glioblastoma (GBM) is the most aggressive primary brain tumor with a median survival of 15 months despite standard care therapy consisting of maximal surgical debulking, followed by radiation therapy with concurrent and adjuvant temozolomide treatment. The natural history of GBM is characterized by inevitable recurrence with patients dying from increasingly resistant tumor regrowth after therapy. Several mechanisms including inter- and intratumoral heterogeneity, the evolution of therapy-resistant clonal subpopulations, reacquisition of stemness in glioblastoma stem cells, multiple drug efflux mechanisms, the tumor-promoting microenvironment, metabolic adaptations, and enhanced repair of drug-induced DNA damage have been implicated in therapy failure. Extracellular vesicles (EVs) have emerged as crucial mediators in the maintenance and establishment of GBM. Multiple seminal studies have uncovered the multi-dynamic role of EVs in the acquisition of drug resistance. Mechanisms include EV-mediated cargo transfer and EVs functioning as drug efflux channels and decoys for antibody-based therapies. In this review, we discuss the various mechanisms of therapy resistance in GBM, highlighting the emerging role of EV-orchestrated drug resistance. Understanding the landscape of GBM resistance is critical in devising novel therapeutic approaches to fight this deadly disease.

Sequencing studies have provided novel insights into the heterogeneous molecular landscape of glioblastoma (GBM), unveiling a subset of patients with gene fusions. Tissue biopsy is highly invasive, limited by sampling frequency and incompletely representative of intra-tumor heterogeneity. Extracellular vesicle-based liquid biopsy provides a minimally invasive alternative to diagnose and monitor tumor-specific molecular aberrations in patient biofluids. Here, we used targeted RNA sequencing to screen GBM tissue and the matched plasma of patients (n = 9) for RNA fusion transcripts. We identified two novel fusion transcripts in GBM tissue and five novel fusions in the matched plasma of GBM patients. The fusion transcripts FGFR3-TACC3 and VTI1A-TCF7L2 were detected in both tissue and matched plasma. A longitudinal follow-up of a GBM patient with a FGFR3-TACC3 positive glioma revealed the potential of monitoring RNA fusions in plasma. In summary, we report a sensitive RNA-seq-based liquid biopsy strategy to detect RNA level fusion status in the plasma of GBM patients.

Pediatric aneurysms commonly occur in the vertebrobasilar circulation with complex morphologies.1 “Aneurysmal malformations”, or fistulous vessel dilations without a nidus have also been described.2 Vessel friability and sensitivity to blood loss can complicate surgery. A 21-month-old male with motor and speech delay was found to have a giant posterior fossa aneurysmal malformation. He was lethargic, with minimal speech, and moved all extremities with mild hypotonia. Imaging demonstrated a 6.9x5.1x4.6 cm aneurysm arising from a fenestrated right V4 segment. This communicated via a single connection with the deep venous system, draining through the superior vermian cistern veins, posterior mesencephalic vein, basal vein of Galen, and inferior sagittal sinus, consistent with an arteriovenous fistula with secondary aneurysmal dilatation. Endovascular sacrifice was not feasible, in addition to concern for swelling after embolization. Three-dimensional modeling confirmed close proximity of the single inflow and outflow tracts. A suboccipital and left far lateral craniotomy for clip trapping and excision of the aneurysmal arteriovenous malformation was performed in a lateral position to completely decompress the brainstem (Video 1). Angiography prior to closure and post-operative vascular imaging demonstrated complete aneurysmal resection and fistula disconnection, with patency of normal vasculature. The post-operative course was notable for transient swallowing difficulties likely from lower cranial nerve irritation, and refractory hydrocephalus requiring a shunt. The patient was meeting all developmental milestones on two-year follow up. This case highlights the complex vascular pathology often seen in pediatric patients, and the importance of pre-surgical planning and careful microsurgical technique in achieving a successful outcome.

The operative exoscope is a novel tool that combines the benefits of surgical microscopes and endoscopes to yield excellent magnification and illumination while maintaining a comparatively small footprint and superior ergonomic features. Until recently, current exoscopes have been limited by 2-dimensional viewing; however, recently a 3-dimensional (3D), high-definition (4K-HD) exoscope has been developed (Sony-Olympus, Tokyo, Japan). 1 Our group had previously described the first in-human experiences with this novel tool including microsurgical clipping of intracranial aneurysms. We have highlighted the benefits of the exoscope, which include providing an immersive experience for surgeons and trainees, as well as superior ergonomics as compared with traditional microsurgery. 2 To date, exoscopic 3D high-definition indocyanine green (ICG) video angiography (ICG-VA) has not been described. ICG-VA, now a mainstay of vascular microsurgery, uses intravenously injected dye to visualize intravascular fluorescence in real time to assess the patency of arteries and assess clip occlusion of aneurysms. 3 , 4 The ability to safely couple this tool with the novel exoscope has the potential to advance cerebrovascular microsurgery. Here, we present a case of a 11-year-old male with Alagille syndrome, pancytopenia, and peripheral pulmonary stenosis found to have a 12 × 13 × 7 mm distal left M1 aneurysm arising from the inferior M1/M2 junction. The patient was neurologically intact without evidence of rupture. In order to prevent catastrophic rupture, the decision was made to treat the lesion. Due to the patients underlying medical conditions including baseline coagulopathy, surgical management was felt to be superior to an endovascular reconstruction, which would require long-term antiplatelet therapy. Thus the patient underwent a left-sided pterional craniotomy with exoscopic 3D ICG-VA. As demonstrated in Video 1 , ICG-VA was performed before definitive clip placement in order to understand flow dynamics with particular emphasis on understanding the middle cerebral artery outflow. Postoperatively, the patient remained at his neurologic baseline and subsequent imaging demonstrated complete obliteration of the aneurysm without any neck remnant. The patient continues to follow and remains asymptomatic and neurologically intact without radiographic evidence of residual or recurrence.

BACKGROUND Although mechanical thrombectomy has become the standard of care for large-vessel occlusion, the role of conscious sedation versus general anesthesia (GA) with intubation during thrombectomy remains controversial. Aphasia may increase patient agitation or apparent uncooperativeness/confusion and thereby lead to higher use of GA. The purpose of this study was to identify risk factors for GA and determine if the side of vessel occlusion potentially impacts GA rates. MATERIALS AND METHODS Patients who underwent mechanical thrombectomy of the middle cerebral artery (MCA) for acute ischemic stroke at our institution between April 2014 and July 2017 were retrospectively reviewed. Patient characteristics, procedural factors, and outcomes were assessed using multivariate regression analyses. Mediation analysis was utilized to investigate whether aphasia lies on the causal pathway between left-sided MCA stroke and GA. RESULTS Overall, 112 patients were included: 62 with left-sided and 50 with right-sided MCA occlusion. Patients with left-sided MCA occlusion presented with aphasia significantly more often those with right-sided occlusion (90.3% vs. 32.0%; P