Clinicopathological analysis of rosette-forming glioneuronal tumors.

BACKGROUND: This study aimed to investigate the clinicopathological characteristics, diagnostic indicators, and critical factors for the differential diagnosis of rosette-forming glioneuronal tumor (RGNT). PATIENTS AND METHODS: This retrospective study included six surgically treated RGNT cases. We analyzed and summarized their clinical manifestations, radiological features, histological morphology, immunophenotype, and molecular genetic changes, supplemented with a literature review. RESULTS: The patients comprised four males and two females with a mean age of 35 years. The tumors were located in the cerebellum (two cases); the fourth ventricle, quadrigeminal cistern, and third ventricle (one case each); and the fourth ventricle and brainstem (one case). Clinical manifestations included headaches in four cases, left eyelid ptosis in one case, and one asymptomatic case only identified during physical examination. Microscopically, the tumor cells were uniform in size and were marked by rosette-like or pseudorosette-like structures around the neuropil and blood vessels. Immunohistochemistry revealed biphasic patterns. The central neuropil components of the rosette-like structures around the neuropil and the pseudorosette structures of the perivascular regions expressed Syn, while the cells surrounding the rosettes expressed Olig2 and not GFAP. GFAP and S-100 were expressed in the glial components but not in the rosette or pseudorosette regions. The Ki-67 proliferation index was typically low. Molecular genetic analysis showed that the main molecular changes involved FGFR1 mutation accompanied by PIK3R1 mutation. None of the patients received chemoradiotherapy postoperatively. Follow-up durations varied between 4 and 23 months with no recorded recurrence or metastasis. CONCLUSION: RGNT is a comparatively rare mixed glioneuronal tumor that occurs in the midline structures. Its morphology shows certain overlaps with other low-grade neuroepithelial tumors. Identifying the rosettes around the neuropil is critical for morphological diagnosis, and the molecular identification of FGFR1 mutations accompanied by PIK3R1 mutations can facilitate diagnosis.

Successful Surgical Resection of an Ependymal Cyst in the Fourth Ventricle of a Dog.

Ependymal cysts represent congenital brain malformations rarely described in human medicine, where surgical resection is the treatment of choice. In veterinary medicine, only three cases have been previously reported, with one partially resected with surgery. A 6 yr old entire male American Staffordshire terrier was referred with a 4 mo history of incoordination and collapsing episodes with extensor rigidity. Neurological examination localized the lesion to the left central vestibular system and cerebellum. A brain computed tomography scan showed a hypoattenuating lesion with peripheral contrast enhancement in the fourth ventricle consistent with a cyst and secondary hydrocephalus. Treatment with prednisone was initiated, but despite an initial improvement, neurologic signs recurred and a suboccipital craniectomy to remove the cyst was performed. The cyst was first drained, and the capsule was carefully resected. The histopathological evaluation revealed a simple cubic to cylindrical epithelium with apical cilia and loose surrounding fibrillar tissue consistent with an intraventricular ependymal cyst. Four and a half years after surgery, the dog only shows short episodes of balance loss when turning abruptly but is otherwise neurologically normal. To the authors' knowledge, this is the first reported ependymal cyst in the fourth ventricle of a dog with successful surgical resection.

Experience in treating children with ocular dyskinesia and hemifacial spasm secondary to pontine tumours adjacent to the fourth ventricle and systematic review.

OBJECTIVE: To investigate the treatment plan and prognosis of children with ocular dyskinesia and hemifacial spasm secondary to pontine tumours adjacent to the fourth ventricle. METHODS: In this retrospective study, the clinical information of 10 consecutively collected children with ocular dyskinesia and hemifacial spasm secondary to pontine tumours adjacent to the fourth ventricle was analyzed. All 10 children underwent pontine tumour resection through a trans-cerebellomedullary fissure approach; 4 children underwent preoperative diffusion tensor imaging scans to determine the relationship between the tumour and facial nerve nucleus, and the other 6 children underwent intraoperative deep electroencephalography (EEG) tumour monitoring, in which the tumour electrical discharge activity of the tumour was recorded. A voxel distribution map was established to describe the distribution of the tumour location, and patient prognosis was evaluated through clinical and imaging follow-up. RESULTS: All 10 children achieved total tumour resection; 9 tumours were pathologically suggested to be ganglioglioma (WHO grade I), and 1 was a hamartoma. The symptoms of the original ocular dyskinesia and hemifacial spasm disappeared immediately after the operation. The children were followed up for 4-75 months, and none of the symptoms recurred; four cases with preoperative diffusion tensor imaging showed that the tumour was close to the facial nerve. Four in six intraoperative electrophysiological monitoring showed that the tumour had electrical discharge behaviour, and the tumour distribution map indicates a high density of tumour presence in the facial nerve nucleus and the nucleus of the abducens nerve. CONCLUSIONS: In paediatric patients, the facial symptoms are related to the location and abnormal electrical discharge of the tumour. There is no significant correlation between ocular dyskinesia and the location of the tumour. Conventional antiepileptic therapy for this disease is ineffective, and early surgical intervention for total tumour resection can achieve a clinical curative effect.

Intrathecal injection of methotrexate and dexamethasone for vasculitis granuloma of the fourth ventricle: a case report and literature review.

Granulomatosis with polyangiitis (GPA) is a pauci-immune small vessel vasculitis characterised by neutrophil-mediated vasculitis and granuloma. The presence of intracranial parenchymal space-occupying lesions is rarely seen in GPA patients. In this manuscript, we report a case of GPA with granuloma of the fourth ventricle accompanied by obstructive hydrocephalus. Treatment with glucocorticoids (GCs) and multiple immunosuppressants cyclophosphamide (CYC), mycophenolate mofetil (MMF), and rituximab (RTX) showed poor efficacy in this case. After removal of the granuloma by craniotomy, GPA relapsed within 3 months. Under the premise of GC and MMF treatment combined with intrathecal injection of dexamethasone (DXM) and methotrexate (MTX), the intracranial granuloma gradually shrank, and the patient's general condition was alleviated, showing that this is an effective treatment method. Key Points • To date, there are few reports of granulomatous vasculitis combined with granuloma of the fourth ventricle, and our case is the second. • In this case, multiple immunosuppressants and rituximab were ineffective treatments, and the intracranial granuloma was effectively controlled by intrathecal injection of dexamethasone (DXM) and methotrexate (MTX). • Based on this report, it can be suggested that intrathecal injection is effective in treating patients with GPA and central nervous system involvement, but large-scale sample studies are needed.

The presence of a foramen of Luschka in the American alligator (Alligator mississippiensis) and the continuity of the intraventricular and subdural spaces.

In humans and most mammals, there is a notch-like portal, the foramen of Luschka (or lateral foramen), which connects the lumen of the fourth ventricle with the subdural space. Gross dissection, light and scanning electron microscopy, and µCT analysis revealed the presence of a foramen of Luschka in the American alligator (Alligator mississippiensis). In this species, the foramen of Luschka is a notch in the dorsolateral wall of the pons immediately caudal to the peduncular base of the cerebellum, near the rostral end of the telovelar membrane over the fourth ventricle. At the foramen of Luschka there was a transition from a superficial pia mater lining to a deep ependymal lining. There was continuity between the lumen of the fourth ventricle and the subdural space, via the foramen of Luschka. This anatomical continuity was further demonstrated by injecting Evans blue into the lateral ventricle which led to extravasation through the foramen of Luschka and pooling of the dye on the lateral surface of the brain. Simultaneous subdural and intraventricular recordings of cerebrospinal fluid (CSF) pressures revealed a stable agreement between the two pressures at rest. Perturbation of the system allowed for static and dynamic differences to develop, which could indicate varying flow patterns of CSF through the foramen of Luschka.

Is Antihelminthics Necessary in Postoperative Treatment of Intraventricular Neurocysticercosis? A Systematic Review.

OBJECTIVE: Patients with intraventricular neurocysticercosis (IVNCC) may require cerebrospinal fluid diversion surgery for late-onset hydrocephalus in the postsurgical period. Controversy exists regarding cysticidal treatment. Our main objective was to compare surgically treated cases of IVNCC that received postoperative anthelmintics with those that did not regard the incidence and treatment of late-onset hydrocephalus. METHODS: We searched the Medline database and extracted the following data: age, gender, stage of development of cysticercosis, type of operation, frequency of delayed hydrocephalus, cerebrospinal fluid diversion surgery, outcome, and follow-up. RESULTS: We analyzed 130 articles on intraventricular cysticercosis and identified 117 cases of isolated IVNCC and 314 patients in the case-control series who met inclusion criteria. There was no significant difference in postoperative delayed hydrocephalus between isolated IVNCC and case-control study groups. Children under the age of 16 received anthelmintic drugs more frequently during the postoperative period. Statistical relevance was observed in all patient groups regarding the application of steroids in favor of cysticidal therapy Endoscopy was a better option than craniotomy for cases of isolated IVNCC and case-control studies. Other variables were not relevant. CONCLUSIONS: Patients who received antihelminths did not show a statistically significant reduction in delayed hydrocephalus compared to individuals who did not receive after surgical resection of the parasite. Corticosteroid therapy prevailed in people who have been treated with anthelmintics. Children under the age of 16 were administered anthelmintic drugs more frequently during the postoperative period. Endoscopy was the preferred method for all groups, but some patients with cysts in the fourth ventricle required a craniotomy.

Treatment of brainstem and fourth ventricle lesions by the full neuroendoscopic telovelar approach.

OBJECTIVE: To explore the surgical techniques, advantages, and disadvantages of neuroendoscopic telovelar approach in the treatment of brainstem and fourth ventricle lesions. METHODS: The clinical data of 5 patients treated by neuroendoscopic telovelar approach from March 2020 to March 2022 were analyzed retrospectively. RESULTS: Among the 5 patients, there were 3 cavernous hemangiomas in pontine arm and 2 tumors in brainstem and fourth ventricle. All patients could successfully complete the operation, and 4 patients recovered well, other 1 patient discharged automatically for serious complications of other systems after the operation. CONCLUSION: The telovelar approach has gained popularity as a safe and effective strategy for lesions in fourth ventricular and brainstem. However, without removing the posterior arch of the atlas, it is difficult to enter the upper part of the fourth ventricle under a microscope. Transcranial neuroendoscopy can effectively compensate for the shortcomings of microscopy, whether used as an auxiliary measure for microsurgery or alone with proficient endoscopic techniques, it will provide greater application in minimally invasive surgery for fourth ventricle and brainstem lesions. By utilizing the excellent degree of freedom of transcranial neuroendoscopy, there is no need to open the posterior arch of the atlas, making the surgery more minimally invasive. However, the sample size of this study is small, and it was completed under the very mature neuroendoscopic technology of our team. Its general safety and practicality still require extensive clinical research validation.

Subependymomas of the fourth ventricle: To operate or not to operate?

BACKGROUND: There is a paucity of literature regarding the clinical characteristics and management of subependymomas of the fourth ventricle due to their rarity. Here, we describe the operative and non-operative management and outcomes of patients with such tumors. METHODS: This retrospective single-institution case series was gathered after Institutional Review Board (IRB) approval. Patients diagnosed with a subependymoma of the fourth ventricle between 1993 and 2021 were identified. Clinical, radiology and pathology reports along with magnetic resonance imaging (MRI) images were reviewed. RESULTS: Patients identified (n = 20), showed a male predominance (n = 14). They underwent surgery (n = 9) with resection and histopathological confirmation of subependymoma or were followed with imaging surveillance (n = 11). The median age at diagnosis was 51.5 years. Median tumor volume for the operative cohort was 8.64 cm3 and median length of follow-up was 65.8 months. Median tumor volume for the non-operative cohort was 0.96 cm3 and median length of follow-up was 78 months. No tumor recurrence post-resection was noted in the operative group, and no tumor growth from baseline was noted in the non-operative group. Most patients (89 %) in the operative group had symptoms at diagnosis, all of which improved post-resection. No patients were symptomatic in the non-operative group. CONCLUSIONS: Surgical resection is safe and is associated with alleviation of presenting symptoms in patients with large tumors. Observation and routine surveillance are warranted for smaller, asymptomatic tumors.

Endoscopic trans-Magendie foramen biopsy of the superior medullary velum: Technical note.

BACKGROUND: Surgery of the fourth ventricle is challenging due to the presence of several surrounding delicate structures. Traditional approaches do not offer an easy visualization of these areas, especially those on the roof. Thanks to the most recent developments in neurosurgical endoscopy, it is possible to access the fourth ventricle via physiological pathways, avoiding unnecessary stress or damage to the nervous and vascular structures. METHODS: We present the case of a patient with a lesion at the lingula-superior medullary velum, and an history of surgically resected lung and pancreatic adenocarcinomas. An endoscopic biopsy of the lesion through the foramen of Magendie was performed. The few reports on this endoscopic approach were also critically reviewed. RESULTS: The retrograde endoscopic exploration through a suboccipital, trans-Magendie foramen approach using a flexible endoscope allowed the clear visualization of the superior medullary velum and the possibility to obtain diagnostic biopsies of the lesion with a minimally invasive technique. CONCLUSIONS: The trans-Magendie navigation with a flexible endoscope is a safe and elegant technique to approach lesions located in any point of the fourth ventricle, particularly in its rostral portion.

Transpeduncular Approach for Resection of Ruptured Fourth Ventricular Arteriovenous Malformation.

The lateral recess of the fourth ventricle can be challenging to access surgically. We present a case of a previously ruptured arteriovenous malformation (AVM) of the fourth ventricle that was surgically resected via a retrosigmoid craniotomy and transinferior cerebellar peduncular approach. The patient is a 54-year-old female who experienced an intraventricular hemorrhage several months before presentation to our institution. Imaging studies suggested the presence of an AVM located in the right lateral recess of the fourth ventricle. After discussion of all possible treatment options, the patient elected to proceed with surgical resection. To access the lesion, we performed a retrosigmoid craniotomy and entered into the fourth ventricle via s small incision in the inferior cerebellar peduncle. Postoperative imaging demonstrated complete removal of the AVM nidus. Video 1 demonstrates this approach and discusses the anatomic landmarks used to guide resection.

Intraoperative Neurophysiologic Monitoring in Predicting Dysphagia After Brainstem and Fourth Ventricle Surgery.

OBJECTIVE: Dysphagia represents the main complication of posterior fossa neurosurgery. Adequate diagnosis of this complication is warranted to prevent untimely extubation with subsequent aspiration. Intraoperative neurophysiologic monitoring (IONM) modalities may be used for this purpose. However, it is not known which IONM modality may be significant for diagnosis. This study aimed to define the most significant IONM modality for dysphagia prognostication after posterior fossa neurosurgery. METHODS: The analysis included 46 patients (34 with tumors of the fourth ventricle and 12 with brainstem localization) who underwent surgical excision of the tumor. Neurologic symptoms before and after neurosurgery were noted and magnetic resonance imaging with the subsequent volume estimation of the removed mass was performed, followed by an IONM findings analysis (mapping of the nucleus of the caudal cranial nerves [CN] and corticobulbar motor-evoked potentials [CoMEP]). RESULTS: Aggravation of dysphagia was noted in 24% of the patients, more often in patients with tumor localization in the fourth ventricle (26%) than in those with brainstem mass lesions (16%). Mapping of the caudal cranial nerve nuclei did not correlate with the dysfunction of these structures. CoMEP was significantly associated with the neurologic state of the CN. The decrease in CoMEP is a significant prognostic factor for postoperative bulbar symptoms appearance or aggravation. CONCLUSIONS: Mapping the CN is an important identification tool. The CoMEP modality should be used intraoperatively to determine the functional state of the CN and predict postoperative dysphagia.

FOURTH VENTRICLE ENTRAPMENT MANAGEMENT AND ITS OUTCOMES: CASE-SERIES FROM A SINGLE NEUROSURGERY CENTER.

This case-series aims to report the elaborate management of FVEs in our center and their outcome. Data from 2017 to 2022 were retrospectively collected. We reviewed patient's demography, clinical findings, radiology results, operative procedures, and complications after surgery. Five patients with FVE diagnosis underwent neurosurgical procedures. The procedures include VP shunt, endoscopic cyst fenestration and fourth ventricle peritoneal shunt (FVPS). Out of five patients, 3 had favorable outcomes, 1 deceased, and 1 patient were still hospitalized. The underlying diseases varied from hemorrhage, cyst, infection, congenital, and neoplasm. FVE etiologies range from congenital to intraventricular hemorrhage complications and infection. VPS, FVPS, and endoscopic treatment with stenting or fenestration are surgical options for treating FVE patients. CSF diversion using shunt device is the simplest procedure. Patients with FVE in general have favorable outcome after CSF diversion of any method.

Effects of the Fourth Ventricle Compression Technique and Rib Raising Osteopathic Technique on Autonomic Nervous System Activity Measured by Heart Rate Variability in 35 Healthy Individuals.

BACKGROUND Fourth ventricle compression (CV4) is a cranial osteopathic manipulation technique for brain and cranial nerve function. Rib raising is an osteopathic technique that reduces rib restriction and conditions associated with sympathetic hypertonia. This study aimed to evaluate the effects of the CV4 and rib raising osteopathic techniques on autonomic nervous system activity, measured by heart rate variability, in 35 healthy individuals. MATERIAL AND METHODS The study involved 35 healthy participants, randomly divided into 2 groups. The experimental group received osteopathic therapy in the form CV4 and rib raising techniques for 30 min. The placebo group had a sham procedure performed using an ultrasound transducer for 20 min. The test of heart rate variability was conducted for 6 min, with participants in a seated position. RESULTS A significant decrease in heart rate values was observed in the experimental group (P=0.012), and an increase in the standard deviation of all the rib raising intervals parameter and a decrease in the high frequency% parameter was observed in the placebo group (P=0.035, P=0.048; respectively). There were no differences in other parameters between the groups. CONCLUSIONS The use of the CV4 technique and rib raising technique leads to a significant decrease in heart rate, which can be interpreted as increased parasympathetic activity; however, the use of these techniques did not affect the other parameters.

The different shapes of the fourth ventricle.

With a distinctive shape and surrounding anatomical structures, the fourth ventricle is located in the posterior cranial fossa. There are various pathologies, either developmental or acquired, that can present as a characteristic deformity of the fourth ventricle. Therefore, this paper will cover the anatomy of the fourth ventricle and correlate this to the various pathologies. The aim of this review is to improve the ability of the readers to recognise the change in shape and configuration of the fourth ventricle, enabling early detection of pathologies.

Predictors of postoperative complications and functional outcomes in pediatric patients with surgically treated fourth ventricle tumors.

BACKGROUND: Tumors of the fourth ventricle are frequently treated pathologies in pediatric neurosurgery. Data regarding predictors for permanent neurological deficits, long-term functional outcomes, cerebellar mutism (CM), the extent of resection (EOR), and oncological outcomes are scarce. We attempt to contribute to this topic with an analysis of our institutional cohort. METHODS: A retrospective single-center study of patients aged ≤ 19 years who underwent primary surgical resection of a fourth ventricular tumor over a 15-year period (2006-2021). Predictors analyzed included age, gender, surgical approach, anatomical pattern, tumor grade, EOR, tumor volume, and others as appropriate. RESULTS: One hundred six patients were included (64 males, mean age 7.3 years). The rate of permanent neurological deficit was 24.2%; lateral tumor extension (p = 0.036) and tumor volume greater than 38 cm3 (p = 0.020) were significant predictors. The presence of a deficit was the only significant predictor of reduced (less than 90) Lansky score (p = 0.005). CM occurred in 20.8% of patients and was influenced by medulloblastoma histology (p = 0.011), lateral tumor extension (p = 0.017), and male gender (p = 0.021). No significant difference between the transvermian and telovelar approach in the development of CM was detected (p = 0.478). No significant predictor was found for the EOR. EOR was not found to be a significant predictor of overall survival for both low-grade and high-grade tumors; however, gross total resection (GTR) was protective against tumor recurrence compared to near-total or subtotal resection (p < 0.001). In addition, survival was found to be better in older patients (≥ 7.0 years, p = 0.019). CONCLUSION: The overall rate of postoperative complications remains high due to the eloquent localization. Older patients (> 7 years) have been found to have better outcomes and prognosis. Achieving GTR whenever feasible and safe has been shown to be critical for tumor recurrence. CM was more common in patients with medulloblastoma and in patients with tumors extending through the foramen of Luschka. The telovelar approach uses a safe and anatomically sparing corridor; however, it has not been associated with a lower incidence of CM and neurological sequelae in our series, showing that each case should be assessed on an individual basis.

Rare Case of Hemorrhagic Atypical Choroid Plexus Papilloma of Fourth Ventricle in Adult: A Diagnostic Dilemma.

Choroid plexus papillomas are highly vascular tumors, and such tumors causing subarachnoid hemorrhage have been reported in literature. Similarly, few articles have reported atypical fourth ventricular choroid plexus tumors in adults. However, such an atypical tumor presenting with grossly hemorrhagic transformation without any acute symptoms could not be found in the literature.