Alteration of the translational readthrough isoform AQP4ex induces redistribution and downregulation of AQP4 in human glioblastoma.

Glioblastoma multiforme (GBM) is characterized by a remarkable cellular and molecular heterogeneity that make the behavior of this tumor highly variable and resistant to therapy. In addition, the most serious clinical complication of GBM and other brain tumors is the development of vasogenic edema which dramatically increase the intracranial pressure. In the present study we evaluate the expression, supramolecular organization and spatial distribution of AQP4 and AQP4ex, the new readthrough isoform of AQP4, in relationship with the degree of vasogenic brain edema and tumor progression. To this purpose, tissue samples from regions of tumor core, peritumoral and non-infiltrated tissues of each GBM patient (n = 31) were analyzed. Immunofluorescence experiments revealed that the expression of AQP4ex was almost absent in tumoral regions while the canonical AQP4 isoforms appear mostly delocalized. In peritumoral tissues, AQP4 expression was found altered in those perivascular astrocyte processes where AQP4ex appeared reduced and partially delocalized. Protein expression levels measured by immunoblot showed that global AQP4 was reduced mainly in the tumor core. Notably, the relative amount of AQP4ex was more severely reduced starting from the peritumoral region. BN-PAGE experiments showed that the supramolecular organization of AQP4 is only partially affected in GBM. Edema assessment by magnetic resonance imaging revealed that the level of AQP4ex downregulation correlated with edema severity. Finally, the degree of BBB alteration, measured with sodium fluorescein content in GBM biopsies, correlated with the edema index and AQP4ex downregulation. Altogether these data suggest that the AQP4ex isoform is critical in the triggering event of progressive downregulation and mislocalization of AQP4 in GBM, which may affect the integrity of the BBB and contributes to accumulation of edema in the peritumoral tissue. Thus, AQP4ex could be considered as a potential early biomarker of GBM progression.

Impact of the associated anorectal malformation on the outcome of spinal dysraphism after untethering surgery.

PURPOSE: To analyze the outcome after untethering surgery in patients with spinal dysraphism (SD), with or without associated anorectal malformation (ARM). METHODS: Patients operated on for SD, with (Group A) or without (Group B) associated ARM (1999-2015), were included. The post-operative outcome was analyzed in the two groups in terms of improving of clinical symptoms (neuro-motor deficits, bladder dysfunction, bowel dysfunction) and of instrumental examinations (urodynamics, bladder ultrasound, neurophysiology). Fisher's exact test and χ2 test were used as appropriate; p < 0.05 was considered statistically significant. MAIN RESULTS: Ten patients in Group A and 24 in Group B were consecutively treated. One patient was lost at follow up. Six patients (25%) in Group B underwent prophylactic surgery. The analysis of the pre-operative symptoms in the two groups showed that a significantly higher number of patients in group A needed bowel management and presented with neuro-motor deficits, compared to group B (p = 0.0035 and p = 0.04, respectively). Group A showed a significant post-operative neuro-motor improvement as compared to group B (p = 0.002). CONCLUSIONS: Based on our results, untethering seems to be effective in neuro-motor symptoms in selected patients with ARM. In ARM patients, untethering surgery does not seem to benefit intestinal and urinary symptoms. The presence of the associated ARM does not seem to impact the medium-term outcome of patients operated for SD.

Langerhans' Cell Histiocytosis Mimicking a Pott Puffy Tumor.

Langherans' cell histiocytosis (LCH) is a rare disease mostly affecting children in the first decade of life. As clinical presentation is extremely heterogenous, a prompt diagnosis may be challenging, sometimes leading to a diagnostic delay, especially when the disease involves a single site. Herein, we report a case of a child with an unusual presentation of (LCH) mimicking a Pott puffy tumor with extracranial and epidural abscesses, surgically treated. Through this unique case we summarize possible manifestations of LCH with bone involvement and we underline the importance of considering possible complications due to bone erosions such as infection, to avoid a misdiagnosis.

Robot-assisted procedures in pediatric neurosurgery.

OBJECTIVE During the last 3 decades, robotic technology has rapidly spread across several surgical fields due to the continuous evolution of its versatility, stability, dexterity, and haptic properties. Neurosurgery pioneered the development of robotics, with the aim of improving the quality of several procedures requiring a high degree of accuracy and safety. Moreover, robot-guided approaches are of special interest in pediatric patients, who often have altered anatomy and challenging relationships between the diseased and eloquent structures. Nevertheless, the use of robots has been rarely reported in children. In this work, the authors describe their experience using the ROSA device (Robotized Stereotactic Assistant) in the neurosurgical management of a pediatric population. METHODS Between 2011 and 2016, 116 children underwent ROSA-assisted procedures for a variety of diseases (epilepsy, brain tumors, intra- or extraventricular and tumor cysts, obstructive hydrocephalus, and movement and behavioral disorders). Each patient received accurate preoperative planning of optimal trajectories, intraoperative frameless registration, surgical treatment using specific instruments held by the robotic arm, and postoperative CT or MR imaging. RESULTS The authors performed 128 consecutive surgeries, including implantation of 386 electrodes for stereo-electroencephalography (36 procedures), neuroendoscopy (42 procedures), stereotactic biopsy (26 procedures), pallidotomy (12 procedures), shunt placement (6 procedures), deep brain stimulation procedures (3 procedures), and stereotactic cyst aspiration (3 procedures). For each procedure, the authors analyzed and discussed accuracy, timing, and complications. CONCLUSIONS To the best their knowledge, the authors present the largest reported series of pediatric neurosurgical cases assisted by robotic support. The ROSA system provided improved safety and feasibility of minimally invasive approaches, thus optimizing the surgical result, while minimizing postoperative morbidity.

Embryological and clinical implications of the association between anorectal malformations and spinal dysraphisms.

PURPOSE: To describe the association of anorectal malformation (ARM) and spinal dysraphism (SD) in terms of impact on the management of SD and embryogenetic implications. METHODS: Patients with SD associated with (A) or without (B) ARM were included. The two groups were further divided into operated on (A1/B1) or not (A2/B2) for SD. Groups A and B were compared for type of SD (embryogenetic classification) and prevalence of neurosurgery; Groups A1 vs. A2 for type of ARM (Wingspread classification); Groups A1 vs. B1 for age at neurosurgery, neurophysiology, and clinical symptoms. MAIN RESULTS: One hundred twenty-one patients with SD, 83 with and 38 without ARM were consecutively treated (1999-2015). Group A was associated only with SDs developing after primary neurulation, corresponding to the period of cloacal septation and organogenesis (p = 0.0007). Untethering surgery was significantly less frequent in Group A (p < 0.0001 and p = 0.04, respectively). Higher ARMs were not associated with increased risk for neurosurgery. No other significant differences were detected. CONCLUSIONS: In our series, ARMs were associated only with SD developing after primary neurulation, suggesting a single insult leading to both SD and the associated ARM. Neurosurgery is indicated less frequently in patients with ARM-associated SD, despite the similar preoperative clinical features.

Spinal ependymoma in a patient with Kabuki syndrome: a case report.

BACKGROUND: Kabuki syndrome is a rare disorder characterized by the association of mental retardation and postnatal growth deficiency with distinctive facial appearance, skeletal anomalies, cardiac and renal malformation. Two causative genes have been identified in patients with Kabuki syndrome. Mutation of KMT2D (MLL2) was identified in 55-80% of patients, while 9-14% of KMT2D negative patients have mutation in KDM6A gene. So far, few tumors have been reported in patients with Kabuki syndrome. We describe the first case of a patient with spinal ependymoma and Kabuki syndrome. CASE PRESENTATION: A 23 years old girl followed at our Center for KMT2D mutated Kabuki syndrome since she was 4 years old presented with acute lumbar pain and intermittent tactile hyposthenia of the feet. Spine magnetic resonance revealed a lumbar endocanalar mass. She underwent surgical resection of the lesion and histologic examination showed a tanycytic ependymoma (WHO grade II). CONCLUSION: Kabuki syndrome is not considered a cancer predisposition syndrome. Nonetheless, a number of tumors have been reported in patients with Kabuki syndrome. Spinal ependymoma is a rare disease in the pediatric and young adult population. Whereas NF2 mutations are frequently associated to ependymoma such an association has never been described in Kabuki syndrome. To our knowledge this is the first case of ependymoma in a KMT2D mutated Kabuki syndrome patient. Despite KMT2D role in cancer has previously been described, no genetic data are available for previously reported Kabuki syndrome patients with tumors. Nonetheless, the association of two rare diseases raises the suspicion for a common determinant.

Comparative analysis of explanted DBS electrodes.

BACKGROUND: Hardware-related complications frequently occur in deep brain stimulation. Microscopy and spectroscopy techniques are effective methods for characterizing the morphological and chemical basis of malfunctioning DBS electrodes. A previous report by our team revealed the morphological and chemical alterations on a malfunctioning explanted electrode when it was compared to a new device. The aim of this preliminary study was to verify whether these morphological and chemical alterations in the materials were a direct result of the hardware malfunctioning or if the failure was correlated to a degradation process over time. METHODS: Two DBS electrodes were removed from two patients for reasons other than DBS system impairment and were analyzed by a scanning electron microscope and by an energy-dispersive X-ray spectroscopy. The results were compared to a malfunctioning device and to a new device, previously analyzed by our group. RESULTS: The analysis revealed that the wear of the polyurethane external part of all the electrodes was directly correlated with the duration of implantation period. Moreover, these alterations were independent from the electrodes functioning and from parameters used during therapy. CONCLUSIONS: This is the first study done that demonstrates a time-related degradation in the external layer of DBS electrodes. The analyses of morphological and chemical properties of the implanted devices are relevant for predicting the possibility of hardware's impairment as well as to improve the bio-stability of DBS systems.

Behavioral disorders as unusual presentation of pediatric extraventricular neurocytoma: report on two cases and review of the literature.

BACKGROUND: Extraventricular neurocytomas (EVNs) are rare parenchymal brain tumors, distinct from central neurocytomas that are typically located within the supratentorial ventricular system. Seizures and headache represent the most common symptoms of extraventricular neurocytomas in the cerebral hemisphere both in adult and pediatric population. CASE PRESENTATION: We describe two cases of pediatric EVN with clinical onset characterized by behavioral and attention deficit/ hyperactivity disorders. The association between behavioral/attention disorders in childhood and the presence of a frontal neurocytoma has never been described before. Furthermore, inappropriate levels of inattention, hyperactivity and impulsivity are common among the neurobehavioral and developmental disorders in childhood. We reviewed 43 pediatric cases of extraventricular neurocytoma included in the PubMed database and their clinical presentation, and we never found this unusual relationship. CONCLUSION: In childhood, the attention/hyperactivity disorders seem to be often over-diagnosed. When these deficits are more subtle and do not well-fit in a specific neurocognitive disorder, the clinicians should have a suspicion that they might mask the clinical features of a frontal lesion. This paper is focused on the clinical presentation of the extraventricular neurocytoma and the possible organic etiology of an attention and hyperactivity deficit.

The role of neurosurgeon in the multidisciplinary approach to ectopic or bifocal intracranial germinoma: A systematic review and report of two illustrative cases.

BACKGROUND: Pure germinoma typically originates from the midline and is usually found in the pineal and suprasellar regions in 76-90 % of cases. When it is in both regions, it is considered bifocal (10 % at diagnosis). If pure germinoma is located outside of the midline, it is considered ectopic, with a global incidence of about 0.7 %. The study aims to describe the clinical and surgical approach to patients with atypical intracranial ectopic germinoma (IEG) and bifocal germinoma (BG) through a literature review with the goal to delineate the correct diagnostic and therapeutic pathway, to reduce the diagnostic delay and improve the prognosis of these patients. METHODS: A systematic review of the literature in most common electronic database (PubMed, Ovid MEDLINE and Ovid EMBASE) on IEG and BG, in according with the "PRISMA statement" criteria, from January 1990 to September 2022 was done. In addition, two rare cases of IEG and BG were reported. RESULTS: This systematic review included 16 papers (20 patients) with a final diagnosis of IEG and 30 papers (121 patients) with a final diagnosis of BG. IEGs seems to involve primary basal ganglia (40 %) and corpus callosum (40 %). For IEGs, biopsy (70 %, 14 cases out of 20) was the most common surgical approach: open approach (35 %), stereotactic minimally invasive approach (30 %) or endoscopic trans-sphenoidal approach (5 %). Partial resection was performed in 10 % of cases, whereas a total resection was performed in 20 % of cases. Also for BGs, biopsy was the most common surgical approach in 80 % of patients, whereas surgical resection (partial or total) was performed in 5.3 % of patients. CONCLUSION: IEG and BG are rare type of primary intracranial germ cell tumor, whose unusual location often can cause delays in diagnosis, which can have a significant impact on the patient's prognosis and requiring a multidisciplinary and timely approach.