New CNS tumor classification: The importance in pediatric neurosurgical practice.

Background: The management of the central nervous system (CNS) tumors in the pediatric population is crucial in neurosurgical practice. The World Health Organization (WHO) has evolved its classification of CNS tumors from the 19th century to the 5th edition, published in 2021, incorporating molecular advancements. This transition from morphology to molecular characterization is ongoing. Methods: This manuscript analyzes the modifications introduced in the 5th edition of WHO's CNS tumor classification, particularly focusing on pediatric tumor families. The paper integrates clinical, morphological, and molecular information, aiming to guide pediatric neurosurgeons in their daily practice and interdisciplinary discussions. Results: The 5th edition of the WHO classification introduces a hybrid taxonomy that incorporates both molecular and histological components. The terminology shifts from "entity" to "type" and "subtype," aiming to standardize terminology. Tumor grading experiences changes, integrating molecular biomarkers for prognosis. The concept of integrated layered diagnosis is emphasized, where molecular and histological information is combined systematically. Conclusion: The 5th edition of the WHO CNS classification signifies a paradigm shift toward molecular characterization. The incorporation of molecular advances, the layered diagnostic approach, and the inclusion of clinical, morphological, and molecular information aim to provide comprehensive insights into pediatric CNS tumors. This classification offers valuable guidance for pediatric neurosurgeons, aiding in precise diagnosis and treatment planning for these complex neoplasms.

Identification of senescent, TREM2-expressing microglia in aging and Alzheimer's disease model mouse brain.

Alzheimer's disease (AD) and dementia in general are age-related diseases with multiple contributing factors, including brain inflammation. Microglia, and specifically those expressing the AD risk gene TREM2, are considered important players in AD, but their exact contribution to pathology remains unclear. In this study, using high-throughput mass cytometry in the 5×FAD mouse model of amyloidosis, we identified senescent microglia that express high levels of TREM2 but also exhibit a distinct signature from TREM2-dependent disease-associated microglia (DAM). This senescent microglial protein signature was found in various mouse models that show cognitive decline, including aging, amyloidosis and tauopathy. TREM2-null mice had fewer microglia with a senescent signature. Treating 5×FAD mice with the senolytic BCL2 family inhibitor ABT-737 reduced senescent microglia, but not the DAM population, and this was accompanied by improved cognition and reduced brain inflammation. Our results suggest a dual and opposite involvement of TREM2 in microglial states, which must be considered when contemplating TREM2 as a therapeutic target in AD.

Exploring the Combined Action of Adding Pertuzumab to Branded Trastuzumab versus Trastuzumab Biosimilars for Treating HER2+ Breast Cancer.

The binding activity of various trastuzumab biosimilars versus the branded trastuzumab towards the glycosylated extracellular domain of the human epidermal growth factor receptor 2 (HER2) target in the presence of pertuzumab was investigated. We employed size exclusion chromatography with tetra-detection methodology to simultaneously determine absolute molecular weight, concentration, molecular size, and intrinsic viscosity. All trastuzumab molecules in solution exhibit analogous behavior in their binary action towards HER2 regardless of the order of addition of trastuzumab/pertuzumab. This analogous behavior of all trastuzumab molecules, including biosimilars, highlights the robustness and consistency of their binding activity towards HER2. Furthermore, the addition of HER2 to a mixture of trastuzumab and pertuzumab leads to increased formation of high-order HER2 complexes, up to concentrations of one order of magnitude higher than in the case of sequential addition. The observed increase suggests a potential synergistic effect between these antibodies, which could enhance their therapeutic efficacy in HER2-positive cancers. These findings underscore the importance of understanding the complex interplay between therapeutic antibodies and their target antigens, providing valuable insights for the development of more effective treatment strategies.

Pediatric hemispheric cerebellar low-grade gliomas: clinical approach, diagnosis, and management challenges-experience at a tertiary care children's hospital.

PURPOSE: This study aims to provide an exhaustive analysis of pediatric low-grade gliomas (pLGGs) in the cerebellar hemispheres, focusing on incidence, clinical characteristics, surgical outcomes, and prognosis. It seeks to enhance understanding and management of pLGGs in the pediatric population. METHODS: We conducted an observational, descriptive, retrospective, and cross-sectional study at a pediatric hospital, reviewing medical records of 30 patients with cerebellar hemispheric pLGGs treated from December 2014 to January 2023. Data collection included demographics, clinical presentation, imaging findings, surgical approach, postoperative complications, histopathological diagnosis, hydrocephalus management, and follow-up. Molecular markers and adjuvant therapies were also analyzed. RESULTS: The cohort predominantly presented with cerebellar symptoms, with 60% showing hydrocephalus at diagnosis. MRI with gadolinium was crucial for diagnosis. Surgical focus was on achieving gross total resection (GTR), accomplished in 70% of cases. Postsurgical hydrocephalus was less common, and cerebellar mutism was not reported. While a complete molecular analysis was not performed in all cases, available data suggest significant influence of molecular markers on prognosis and therapeutic options of pLGGs. CONCLUSIONS: This study highlights the unique clinical and molecular characteristics of cerebellar hemispheric pLGGs in children. The lower incidence of postoperative hydrocephalus and absence of cerebellar mutism are notable findings. Emphasizing a multidisciplinary approach, our findings contribute to a deeper understanding of pediatric pLGGs, underscoring the need for personalized treatment strategies and vigilant follow-up.

Tumors of the central nervous system. Classification of the World Health Organization 2021. Towards a paradigm shift. / Tumores del sistema nervioso central. Clasificación de la Organización Mundial de la Salud 2021. Hacia un cambio de paradigma.

The study of central nervous system (CNS) tumors is a subject of great interest and such knowledge is of great importance in medical practice. The classifications of CNS neoplasms began in the mid-19th century, until the World Health Organization (WHO) published, in 1979, the first edition of a useful systematic review for the purpose of establishing a common language for all medical specialties. To date, 5 updated editions of neoplastic taxonomy have been published. The fifth edition, from 2021, consolidates the paradigm shift brought about by molecular advances, although the transition between morphological and molecular biological characterization is still in progress. In this article, the new modifications introduced in the different most frequent families of tumors in pediatrics are analyzed, emphasizing useful information for pediatricians in their daily practice and multidisciplinary consultations.

El estudio de los tumores del sistema nervioso central (SNC) resulta ser un tema de gran consideración y su conocimiento reviste una alta importancia en la práctica médica. Las clasificaciones de las neoplasias del SNC comenzaron a mediados del siglo XIX hasta que en 1979 la Organización Mundial de la Salud (OMS) publicó la primera edición de una sistemática útil con el objetivo de establecer un lenguaje común para todas las especialidades médicas. Al día de hoy, 5 ediciones actualizaron la taxonomía neoplásica. La quinta edición del año 2021 consolida el cambio de paradigma dado por los avances moleculares, si bien todavía la transición se encuentra en proceso entre la caracterización morfológica y la biológica molecular. En este artículo, se analizan las nuevas modificaciones incorporadas en las diferentes familias tumorales más frecuentes en pediatría haciendo hincapié en aquella información de utilidad para el médico pediatra en su práctica diaria y la consulta multidisciplinaria.

Microsurgical management of radicular cyst using guided tissue regeneration technique: A case report.

BACKGROUND: Radicular cyst is a lesion of odontogenic origin that arises from epithelial remains due to periapical periodontitis caused by inflammatory reactions generated at the apex of affected teeth with infected or necrotic pulps. The therapeutic management of radicular cysts is controversial. There is only one case report of enucleation of a radicular cyst managed with microsurgery and apicoectomy, but without the use of the guided tissue regeneration (GTR) technique in the same surgical procedure. The present clinical case describes the management of a radicular cyst with microsurgical approach, performance of an apicoectomy of the tooth associated with the entity, application of GTR technique, use of a resorbable membrane of type I bovine collagen, and bovine xenograft. CASE SUMMARY: A 68-year-old patient presented with a radicular cyst from an upper lateral incisor. The microsurgical management used was aimed at enucleating the chemical membrane, performing apicoectomy of the tooth along with careful and precise retrograde filling, and implementing GTR technique using a resorbable collagen membrane and bovine xenograft. The diagnosis of radicular cyst was confirmed using histopathological analysis. The patient underwent follow-up evaluations at 10 and 30 d postoperatively. At 4 months postoperative evaluation, she remained asymptomatic, and radiographs showed significant periapical healing with adequate bone formation. CONCLUSION: These results suggest that microsurgical management using the GTR technique with collagen membrane and xenograft, contributes to bone regeneration.

Giant brainstem cavernoma in pediatrics: diagnosis and treatment-case report.

INTRODUCTION: Brain cavernomas or cavernous angiomas are a rare vascular malformation in the general population, even more so in pediatric patients. Their incidence in this group is less than 5% of all vascular malformations. They are typically found in the cerebral hemispheres in cortico-subcortical locations and, more rarely, in the brainstem. OBJECTIVE: To describe the diagnosis, treatment, and follow-up of a case involving a pediatric patient with a giant cavernoma in the brainstem at J.P. Garrahan Hospital. MATERIALS AND METHODS: The clinical history of the case was retrieved from the database of J.P. Garrahan Pediatric Hospital. Additionally, a literature search was conducted in high-impact factor journals using the PubMed database. CONCLUSION: Both the authors of this study and experts consulted through the literature agree that, given the eloquence of the affected area and its challenging accessibility, close monitoring and an expectant approach are advisable for such patients. Nevertheless, when the onset of the case warrants it, surgical intervention is deemed necessary in emergency situations and following the acute phase for complete resolution of the pathology.

Variation of Plasma Damage-Associated Molecular Patterns in Patients with Advanced Solid Tumors after Standard of Care Systemic Treatment.

BACKGROUND: Immunogenic cell death (ICD) is known for releasing damage-associated molecular patterns (DAMPs) from tumor cells. We aimed to find ICD signals by assessing the variation of plasmatic DAMPs (HMGB1, S100A8) before-after standard of care (SoC) systemic treatment in patients with advanced solid tumors. METHODS: Patients scheduled to start a new line of systemic treatment were included. Plasmatic concentrations of HMGB1 and S100A8 were measured (ng/mL) before and after three months of treatment. RESULTS: Fifty-two patients were included. Forty-four patients (85%) had metastases, and 8 (15%) were treated for stage III tumors. The most frequent tumor sites were colorectal (35%) and lung (25%). Forty-two patients (81%) received this treatment in the first-line setting. Thirty-six patients (69%) were treated chemotherapy (CT) alone, ten (19%) CT plus targeted therapy, two (3.8%) carboplatin-pemetrexed-pembrolizumab, three (5.8%) pembrolizumab alone and one (1.9%) cetuximab alone. Median plasmatic concentration of S100A8 was significantly higher before than after treatment in the whole population (3.78 vs. 2.91 ng/mL; p = 0.011) and more markedly in the subgroups of patients who experienced RECIST-assessed tumor response (5.70 vs. 2.63 ng/mL; p = 0.002). Median plasmatic concentration of HMGB1was not significantly different before and after treatment (10.23 vs. 11.85 ng/mL; p = 0.382) and did not differ depending on tumor response. Median PFS was not significantly different between patients whose plasma HMBG1 concentration decreased or increased (8.0 vs. 10.6 months; p = 0.29) after treatment. Median PFS was significantly longer in those patients in whom the plasma concentration of S100A8 decreased after treatment (12 vs. 4.7 months; p < 0.001). Median OS was not significantly different between patients whose plasma HMBG1 concentration decreased or increased (13.1 vs. 14.7 months; p = 0.46) after treatment. Median OS was significantly longer in those patients in whom the plasma concentration of S100A8 decreased after treatment (16.7 vs. 9.0 months; p < 0.001). CONCLUSIONS: Signals of ICD were not observed. S100A8 behaves as an inflammatory marker with decreased concentration after treatment, mostly in RECIST-responders. PFS and OS were significantly prolonged in those patients who experienced a decrease of S100A8 compared with those patients who experienced increase of plasma S100A8 at three months.

Binding Affinity of Trastuzumab and Pertuzumab Monoclonal Antibodies to Extracellular HER2 Domain.

The binding affinity of trastuzumab and pertuzumab to HER2 has been studied using both experimental and in silico methods. The experiments were conducted using the antibodies in their complete IgG form, as used in clinical therapy, and the extracellular domain of the HER2 protein in solution. This approach provides a precise, reproducible, and reliable view of the interaction between them in physicochemical conditions similar to those found in the tumoral environment. Dynamic light scattering and size exclusion chromatography coupled with tetra detection were utilized to characterize the protein complexes, measure their concentrations, and calculate the equilibrium-free binding energy, ΔGbind. In addition, PRODIGY, a QSAR-like model with excellent predictive ability, was employed to obtain in silico ΔGbind estimations. The results obtained indicate that pertuzumab exhibits a slightly higher binding affinity to HER2 than trastuzumab. The difference in binding affinity was explained based on the contribution of the different interfacial contact (IC) descriptors to the ΔGbind value estimated by the PRODIGY model. Furthermore, experiments revealed that the pertuzumab IgG antibody binds preferentially to two HER2 proteins, one per Fab fragment, while trastuzumab mainly forms a monovalent complex. This finding was interpreted based on a geometrical model that identified steric crowding in the trastuzumab-HER2 complex as compared with the pertuzumab-HER2 complex.

[Solid pseudopapillary neoplasm. Report of three cases and review of the literature]. / Neoplasia sólida pseudopapilar. Reporte de tres casos y revisión de la literatura.

Background: Solid pseudopapillary neoplasm, or Frantz-Gruber tumor, is a diagnostic challenge for the surgical pathologist. It is classified by the WHO as a malignant epithelial tumor of the pancreas, its prevalence is low, it occurs in only 1 to 2% of all malignant tumors of the pancreas, it usually affects mainly young women, its origin is still unclear, it is generally It presents as a solitary, encapsulated lesion, without invasion of peripancreatic tissues with rare cases of metastasis, which is why it is considered a low-grade malignant tumor by the WHO. The objective of this article is to present three clinical cases and to evaluate the epidemiology, clinical manifestations, morphology and immunohistochemical expression of the tumor in a review of the bibliography, as well as to compare it with the cases already reported on the subject. Clinical case: Three cases of Frantz tumor were diagnosed by the pathology department of a tertiary hospital are presented, which correspond to two women aged 17 and 34, as well as a 52-year-old man whose presentation by age and sex is rare. Conclusions: After the bibliographical review and the analysis of the cases presented, we verified the difficulty to make a correct diagnosis, since its presence is rare in the daily practice of the surgical pathologist. The morphological patterns of the solid pseudopapillary tumor are varied and can often be reminiscent of neuroendocrine tumors of the pancreas, whose presentation rate is higher.

Inflammatory myofibroblastic tumor of the lung involving the central nervous system in pediatric patients.

INTRODUCTION: The inflammatory myofibroblastic tumor (IMT) is a very rare lesion with an incidence of less than 0.1% of total neoplasms and with main affection in the lungs. Involvement in the central nervous system is extremely rare, but with a much more aggressive course than IMT diagnosed in the rest of the body. We report the 2 cases presented in our neurosurgery department to date; both were treated satisfactorily without intercurrences in 10 years of follow-up. HISTORICAL BACKGROUND: The World Health Organization described the IMT as a distinctive lesion composed of myofibroblastic spindle cells accompanied by an inflammatory infiltrate of plasma cells, lymphocytes, and eosinophils. CLINICAL PRESENTATION: Clinical manifestations of patients with CNS IMT vary and may consist of headache, vomiting, seizures, and blindness. Seizures are the most common symptom in patients with focal lesions. DIAGNOSIS: The true origin of this entity remains to be elucidated, but to date, etiologies ranging from chromosomal alterations to autoimmune or postinfectious mechanisms have been described. Due to its rarity and non-specificity in imaging, the final diagnosis of IMT in the brain parenchyma relies on pathological examination. MANAGEMENT: Treatment options are controversial and include total or subtotal removal, high-dose steroids, and radiation therapy. In the last decade, the development of ALK Tyrosine Kinase Inhibitors allows the possibility of chemotherapy in those patients harboring ALK mutations. CONCLUSION: IMT is a rare tumor that can exceptionally be found in the CNS. The cause is still unknown although the different studies focus on a neoplastic origin. The diagnosis is based in the use of different modalities of imaging and with histological confirmation. Optimal management is gross total resection whenever possible, is the only established curative treatment. Further research with longer follow-up is needed to clarify the natural history of this rare tumor.

Urgent endoscopy versus early endoscopy: Does urgent endoscopy play a role in acute non-variceal upper gastrointestinal bleeding? / Endoscopia urgente frente a endoscopia precoz: ¿tiene algún papel la endoscopia urgente en la hemorragia digestiva alta aguda no varicosa?

INTRODUCTION: The main clinical practice guidelines recommend endoscopy within 24hours after admission to the Emergency Department in patients with non-variceal upper gastrointestinal bleeding. However, it is a wide time frame and the role of urgent endoscopy (<6hours) is controversial. MATERIAL AND METHODS: Prospective observational study carried out at La Paz University Hospital, where all patients were selected, from January 1, 2015 to April 30, 2020, who attended the Emergency Room and underwent endoscopy for suspected upper gastrointestinal bleeding. Two groups of patients were established: urgent endoscopy (<6hours) and early endoscopy (6-24hours). The primary endpoint of the study was 30-day mortality. RESULTS: A total of 1096 were included, of whom 682 underwent urgent endoscopy. Mortality at 30days was 6% (5% vs 7.7%, P=.064) and rebleeding was 9.6%. There were no statistically significant differences in mortality, rebleeding, need for endoscopic treatment, surgery and/or embolization, but there were differences in the necessity for transfusion(57.5% vs 68.4%, P<.001) and the number of concentrates of transfused red blood cells (2.85±4.01 vs 3.51±4.09, P=.008). CONCLUSION: Urgent endoscopy, in patients with acute upper gastrointestinal bleeding, as well as the high-risk subgroup (GBS ≥12), was not associated with lower 30-day mortality than early endoscopy. However, urgent endoscopy in patients with high-risk endoscopic lesions (ForrestI-IIB), was a significant predictor of lower mortality. Therefore, more studies are required for the correct identification of patients who benefit from this medical approach (urgent endoscopy).

Systemic sterile induced-co-expression of IL-12 and IL-18 drive IFN-γ-dependent activation of microglia and recruitment of MHC-II-expressing inflammatory monocytes into the brain.

The development of neuroinflammation, as well as the progression of several neurodegenerative diseases, has been associated with the activation and mobilization of the peripheral immune system due to systemic inflammation. However, the mechanism by which this occurs remains unclear. Here, we addressed the effect of systemic sterile induced-co-expression of IL-12 and IL-18, in the establishment of a novel cytokine-mediated model of neuroinflammation. Following peripheral hydrodynamic shear of IL-12 plus IL-18 cDNAs in C57BL/6 mice, we induced systemic and persistent level of IL-12, which in turn promoted the elevation of circulating pro-inflammatory cytokines TNF-α and IFN-γ, accompanied with splenomegaly. Moreover, even though we identified an increased gene expression of both TNF-α and IFN-γ in the brain, we observed that only IFN-γ, but not TNF-α signaling through its type I receptor, was required to induce both the trafficking of leukocytes from the periphery toward the brain and upregulate MHC-II in microglia and inflammatory monocytes. Therefore, only TNF-α was shown to be dispensable, revealing an IFN-γ-dependent activation of microglia and recruitment of leukocytes, particularly of highly activated inflammatory monocytes. Taken together, our results argue for a systemic cytokine-mediated establishment and development of neuroinflammation, having identified IFN-γ as a potential target for immunomodulation.