BCAS1 defines a heterogeneous cell population in diffuse gliomas.

Oligodendrocyte precursor markers have become of great interest to identify new diagnostic and therapeutic targets for diffuse gliomas, since state-of-the-art studies point towards immature oligodendrocytes as a possible source of gliomagenesis. Brain enriched myelin associated protein 1 (BCAS1) is a novel marker of immature oligodendrocytes and was proposed to contribute to tumorigenesis in non-central nervous system tumors. However, BCAS1 role in diffuse glioma is still underexplored. This study analyzes the expression of BCAS1 in different tumor samples from patients with diffuse gliomas (17 oligodendrogliomas; 8 astrocytomas; 60 glioblastomas) and uncovers the molecular and ultrastructural features of BCAS1+ cells by immunostaining and electron microscopy. Our results show that BCAS1+ cells exhibit stellate or spherical morphology with similar ultrastructural features. Stellate and spherical cells were detected as isolated cells in all studied gliomas. Nevertheless, only stellate cells were found to be proliferative and formed tightly packed nodules with a highly proliferative rate in oligodendrogliomas. Our findings provide a comprehensive characterization of the BCAS1+ cell population within diffuse gliomas. The observed proliferative capacity and distribution of BCAS1+ stellate cells, particularly in oligodendrogliomas, highlight BCAS1 as an interesting marker, warranting further investigation into its role in tumor malignancy.

Ultrastructural Characterization of Human Oligodendrocytes and Their Progenitor Cells by Pre-embedding Immunogold.

Oligodendrocytes are the myelinating cells of the central nervous system. They provide trophic, metabolic, and structural support to neurons. In several pathologies such as multiple sclerosis (MS), these cells are severely affected and fail to remyelinate, thereby leading to neuronal death. The gold standard for studying remyelination is the g-ratio, which is measured by means of transmission electron microscopy (TEM). Therefore, studying the fine structure of the oligodendrocyte population in the human brain at different stages through TEM is a key feature in this field of study. Here we study the ultrastructure of oligodendrocytes, its progenitors, and myelin in 10 samples of human white matter using nine different markers of the oligodendrocyte lineage (NG2, PDGFRα, A2B5, Sox10, Olig2, BCAS1, APC-(CC1), MAG, and MBP). Our findings show that human oligodendrocytes constitute a very heterogeneous population within the human white matter and that its stages of differentiation present characteristic features that can be used to identify them by TEM. This study sheds light on how these cells interact with other cells within the human brain and clarify their fine characteristics from other glial cell types.

Wnt-Dependent Oligodendroglial-Endothelial Interactions Regulate White Matter Vascularization and Attenuate Injury.

Recent studies have indicated oligodendroglial-vascular crosstalk during brain development, but the underlying mechanisms are incompletely understood. We report that oligodendrocyte precursor cells (OPCs) contact sprouting endothelial tip cells in mouse, ferret, and human neonatal white matter. Using transgenic mice, we show that increased or decreased OPC density results in cognate changes in white matter vascular investment. Hypoxia induced increases in OPC numbers, vessel density and endothelial cell expression of the Wnt pathway targets Apcdd1 and Axin2 in white matter, suggesting paracrine OPC-endothelial signaling. Conditional knockout of OPC Wntless resulted in diminished white matter vascular growth in normoxia, whereas loss of Wnt7a/b function blunted the angiogenic response to hypoxia, resulting in severe white matter damage. These findings indicate that OPC-endothelial cell interactions regulate neonatal white matter vascular development in a Wnt-dependent manner and further suggest this mechanism is important in attenuating hypoxic injury.

Ventral Precentral Fiber Intersection Area: A Central Hub in the Connectivity of Perisylvian Associative Tracts.

BACKGROUND: The ventral part of the precentral gyrus is considered one of the most eloquent areas. However, little is known about the white matter organization underlying this functional hub. OBJECTIVE: To analyze the subcortical anatomy underlying the ventral part of the precentral gyrus, ie, the ventral precentral fiber intersection area (VPFIA). METHODS: Eight human hemispheres from cadavers were dissected, and 8 healthy hemispheres were studied with diffusion tensor imaging tractography. The tracts that terminate at the ventral part of the precentral gyrus were isolated. In addition, 6 surgical cases with left side gliomas close to the VPFIA were operated awake with intraoperative electrical stimulation mapping. RESULTS: The connections within the VPFIA are anatomically organized along an anteroposterior axis: the pyramidal pathway terminates at the anterior bank of the precentral gyrus, the intermediate part is occupied by the long segment of the arcuate fasciculus, and the posterior bank is occupied by the anterior segment of the arcuate fasciculus. Stimulation of the VPFIA elicited speech arrest in all cases. CONCLUSION: The present study shows strong arguments to sustain that the fiber organization of the VPFIA is different from the classical descriptions, bringing new light for understanding the functional role of this area in language. The VPFIA is a critical neural epicenter within the perisylvian network that may represent the final common network for speech production, as it is strategically located between the termination of the dorsal stream and the motor output cortex that directly control speech muscles.

Full endoscopic endonasal transsellar-transclival approach: the modularity concept.

BACKGROUND: Endoscopic endonasal approaches (EEAs) constitute a reasonable option for the treatment of lesions that involve the sellar and clival regions. METHODS: We describe, step by step, the full EEA expanded to the middle and lower clivus for the treatment of perisellar lesions. Delimiting different modules around the sellar region is useful in establishing the best endoscopic approach for each tumor. A craniopharyngioma (CP) with clival extension will be used as an illustrative example of the modularity concept of these approaches. CONCLUSIONS: Transsellar-transclival EEA allows complete resection of lesions located in the sellar and infrasellar region with a low rate of complications.

Indocyanine green videoangiography methodological variations: review.

Indocyanine green videoangiography (ICGVA) procedures have become widespread within the spectrum of microsurgical techniques for neurovascular pathologies. We have conducted a review to identify and assess the impact of all of the methodological variations of conventional ICGVA applied in the field of neurovascular pathology that have been published to date in the English literature. A total of 18 studies were included in this review, identifying four primary methodological variants compared to conventional ICGVA: techniques based on the transient occlusion, intra-arterial ICG administration via catheters, use of endoscope system with a filter to collect florescence of ICG, and quantitative fluorescence analysis. These variants offer some possibilities for resolving the limitations of the conventional technique (first, the vascular structure to be analyzed must be exposed and second, vascular filling with ICG follows an additive pattern) and allow qualitatively superior information to be obtained during surgery. Advantages and disadvantages of each procedure are discussed. More case studies with a greater number of patients are needed to compare the different procedures with their gold standard, in order to establish these results consistently.

Fracture of a HTR-PMI cranioplastic implant after severe TBI.

A 13-year-old girl with a large left fronto-parietal hard-tissue replacement patient-matched implant (HTR®-PMI) cranioplasty-since she suffered from a traumatic brain injury (TBI) 6 years ago-had a new severe TBI that detached and fractured the implant as well as caused a left subdural hematoma and a large frontal contusion. The hematoma and contusion were removed and the implant was substituted by a provisional titanium mesh. To the best of our knowledge, this is the first case reported about an HTR®-PMI fracture. It is theorized that the bone ingrowth into the macroporous implants, like those of hydroxyapatite, gives strength and resistance to the implant. But in the case we describe, no macroscopic bone ingrowth was detected 6 years after implantation and the traumatic force that impacted over the cranioplasty exceeded its properties.

Full endoscopic endonasal transclival approach: meningioma attached to the ventral surface of the brainstem.

BACKGROUND: Intracranial meningiomas without dural attachment (MWODA) are rare entities. We present the first case published, to the best of our knowledge, regarding a MWODA attached to the ventral surface of the brainstem. This location makes the patient subsidiary to treatment through an expanded endonasal transclival approach. CLINICAL PRESENTATION: A 16-year-old female with suspected diagnosis of recurrence of a clear cell meningioma (CCM) at a distance from the initial lesion, located on the premedullary cistern. The patient underwent a pure endoscopic low transclival approach. The attachment to the ventral surface of the brainstem was confirmed intraoperatively. Postoperative MRI confirmed gross total resection and treatment was complemented with adjuvant fractionated stereotactic radiotherapy. No complications related to the procedure were observed. CONCLUSION: MWODA may appear attached to the ventral brainstem. The expanded endonasal approach to the clivus provides a critical anatomical advantage in the treatment of medial lesions, even ventral meningiomas, to the lower cranial nerves. Reconstruction principles must be strictly respected to reduce complications.

Microscopic versus endoscopic pituitary surgery.

INTRODUCTION AND OBJECTIVE: The endoscopic techniques used in pituitary surgery have evolved greatly in recent years. Our objective in this study was to conduct a review of the systematic reviews published in the English language literature, to examine their consistency and conclusions reached following studies comparing microsurgery and endoscopic surgery in hypophyseal surgery. MATERIALS AND METHODS: We carried out a bibliographic search on MEDLINE and EMBASE electronic databases, selecting those systematic reviews and meta-analyses published from the year 2000 until January 2013, focusing on comparisons between microsurgical and endoscopic techniques. RESULTS: We concluded with type A consistency that hospital stay was shorter and diabetes insipidus and rhinological complications were less frequent in the endoscopy group. We concluded with type B consistency that lower rates of patient blood loss, shorter operative times, higher rate of gross total resection, lesser association to visual impairment and lower rate of hypopituitarism were observed in the endoscopy group. Vascular complications and cerebrospinal fluid fistulas were reduced with microsurgery. It is crucial to perform a combined analysis of all the systematic reviews treating a specific topic, observing and analysing the trends and how these are affected by new contributions. CONCLUSION: Randomized multicenter studies are necessary to resolve the controversy over endoscopic and microsurgical approaches in hypophyseal pathology.

[Sacral metastasis simulating aneurysmal bone cyst]. / Metástasis sacra simulando quiste óseo aneurismático.

Cystic spinal lesions with characteristic patterns, such as the presence of haematic fluid-fluid levels (H-FFL), have been associated with many tumoral lineages, more frequently with aneurysmal bone cyst (ABC) and exceptionally with metastasis. We present the case of a 60-year-old man with the finding of a sacral cystic bone lesion with H-FFL, with initial suspicion of ABC and confirmed diagnosis of metastasis. The case presented is, to our knowledge, the second case published of spinal cystic bone metastasis with H-FFL pattern with unknown primary tumour at the time of diagnosis and the only one that received resective surgical treatment, achieving pulmonary and metastatic disease control with good quality of life after 1 year of follow up.

[Endonasal skull base endoscopy]. / Endoscopia endonasal de base de cráneo.

INTRODUCTION AND OBJECTIVE: The endoscopic endonasal techniques used in skull base surgery have evolved greatly in recent years. Our study objective was to perform a qualitative systematic review of the likewise systematic reviews in published English language literature, to examine the evidence and conclusions reached in these studies comparing transcranial and endoscopic approaches in skull base surgery. MATERIAL AND METHODS: We searched the references on the MEDLINE and EMBASE electronic databases selecting the systematic reviews, meta-analyses and evidence based medicine reviews on skull based pathologies published from January 2000 until January 2013. We focused on endoscopic impact and on microsurgical and endoscopic technique comparisons. RESULTS: Full endoscopic endonasal approaches achieved gross total removal rates of craniopharyngiomas and chordomas higher than those for transcranial approaches. In anterior skull base meningiomas, complete resections were more frequently achieved after transcranial approaches, with a trend in favour of endoscopy with respect to visual prognosis. Endoscopic endonasal approaches minimised the postoperative complications after the treatment of cerebrospinal fluid (CSF) leaks, encephaloceles, meningoceles, craniopharyngiomas and chordomas, with the exception of postoperative CSF leaks. CONCLUSIONS: Randomized multicenter studies are necessary to resolve the controversy over endoscopic and microsurgical approaches in skull base surgery.