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Introduction: Myxoid glioneuronal tumor of the septum pellucidum is an uncommon clinical entity, previously referred to dysembryoplastic neuroepithelial tumor located in the septum pellucidum., Methods: This study was conducted following PRISMA guidelines. A comprehensive literature search was performed in the PubMed/MEDLINE, Web of Science, and Scopus databases. In addition to the literature review, we report a rare case of a 10-year-old male patient with septal myxoid glioneuronal tumor who underwent endoscopic tumor resection as an exemplary case., Results: A total of 10 pediatric patients from 7 published records were included in this review. An analysis encompassing 11 patients, including the present patient, was performed. The mean age of the patients was 11.36 ± 3.35 years, with a male predominance. The most common presenting symptoms were headache (50%), and seizures (37.5%). Nine patients had microsurgical tumor resection, while 2 patients underwent endoscopic tumor resection. Seven patients underwent gross total or near total resection, while 4 had subtotal resection, and the prognosis for all patients was good., Conclusion: Myxoid glioneuronal tumor of the septum pellucidum represents a rare and relatively benign pathology with typical localization and histopathological features. Surgical resection is the primary treatment modality, aiming for maximal safe resection while preserving neurological function. However, complete resection may not always be achievable due to the infiltrative nature of these tumors and their proximity to critical structures. Generally, the prognosis for these tumors is favorable., Competing Interests: Declarations. Conflict of interest: The authors declare that they have no conflict of interest., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Pediatric cavum cysts are a rare yet complicated pathology to manage. The literature is scarce, primarily consisting of case series, and lacking a consensus regarding clear management. In this scoping review, we aimed to compile existing information in the literature regarding the management of pediatric cavum cysts across the last 10 years. We also present our management of 19 patients, the largest case series to date, highlighting knowledge gaps surrounding the management of this salient pathology., Methods: A literature search using PubMed and SCOPUS was conducted using the following search terms: (pediatric) AND (Cavum septum pellucidum) OR (cavum vergae) OR (cavum velum interpositum) AND (management). Eligibility criteria included peer-reviewed publication published in the last 10 years, pediatric population, cavum cyst, and English language. A retrospective search was conducted for all pediatric cavum cysts between 2013 and 2023 at our institution. Clinical and radiographic characteristics as well as intervention and outcome data were collected for both the scoping review and our cases., Results: 330 total articles were populated using our search. 12 articles met our inclusion criteria. 41.7% (n = 5) of the articles were case series, 33.3% (n = 4) were case reports, 8.3% (n = 1) was a technical article, 8.3% (n = 1) was a systematic review, and 8.3% (n = 1) was a case questionnaire. Resolution of symptoms was noted in all articles of our scoping review, regardless of treatment modality. The average age in our case series was 9.84 years old and average age at diagnosis was 5.53 years old. 6 patients (31.6%) were female and 13 patients (68.4%) were male. 2 out of the 19 patients (10.5%) were surgically treated., Conclusion: There is no clear consensus on the management of cavum cysts. A prospective, multicenter study is needed to create standardized pediatric cyst management guidelines. The current thought is that surgical intervention should be saved for those patients with obstructive hydrocephalus and signs of intracranial hypertension., (© 2024 The Author(s). Published by S. Karger AG, Basel.)

Rationale: Non-Hodgkin lymphoma affecting the brain, eyes, and cerebrospinal fluid without systemic spread is known as primary central nervous system lymphoma (PCNSL). While intracerebroventricular PCNSL is commonly found in the lateral ventricles and the third and fourth ventricles, the occurrence of PCNSL originating from the septum pellucidum is extremely rare., Patient Concerns: Two patients presented with recent memory loss and high cranial pressure., Diagnoses: Magnetic resonance imaging revealed a clear enhancing lesion in the septum pellucidum region. Pathological examination confirmed that both cases were primary large B-cell lymphoma GCB (germinal center B-cell-like) subtypes located in an "immune-privileged" area., Interventions: Both patients underwent total tumor resection, and the procedures were successfully completed without surgical complications., Outcomes: Over a 1-year period, treatment included four cycles of high-dose methotrexate combined with temozolomide. During the follow-up period (19-23 months), no recurrence of the lymphoma was observed., Lessons: In cases of PCNSL in the septum pellucidum, it is crucial to consider it as a potential differential diagnosis for intraventricular tumors. Surgical interventions should focus on maximizing tumor resection while ensuring the protection of critical structures like the fornix and peripheral neural components. The role of surgery compared to biopsy, as well as the long-term complications, necessitates extended follow-up. Additionally, an individualized treatment approach, considering factors such as age, Karnofsky performance score, and organ function assessment, can lead to positive outcomes., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Spontaneous regression of cysts of the cavum septi pellucidi (CSP) and cavum vergae (CV) is rare and little discussed. The authors present their case report of this phenomenon following a severe headache in a 23-year-old woman, in whom magnetic resonance imaging (MRI) had previously confirmed significant thinning of the left lateral cyst wall. We consider this finding to be a possible predisposing factor to rupture and the spontaneous regression of such cysts. In addition to the mechanism of cyst regression, the interrelated causes of their expansion and formation will be discussed., Competing Interests: None declared., (Thieme. All rights reserved.)

Occlusion of foramen of Monro is an uncommon clinical entity that usually presents in children. Common causes are obstructing mass, infectious etiologies or vascular malformation. Rarely, it may be an idiopathic stricture or membrane. We report a case of idiopathic membranous obstruction of the foramen of Monro in a 45-year-old male with no past medical or surgical history. He presented with new intermittent dull and burning bifrontal severe headache for 2 d, which was alleviated slightly by non-steroidal anti-inflammatory medication. Imaging showed marked dilation of the lateral ventricles with normal third and fourth ventricles. The patient was discharged initially with conservative medical management and close follows up; however, the headache continued to progress and neurosurgical intervention was offered. The patient underwent endoscopic exploration, fenestration of the septum pellucidum, and right ventriculoperitoneal shunt placement. Bilateral membranous obstruction of foramina of Monro and an auto-fenestrated cavum septum pellucidum were identified intraoperatively. The patient reported resolution of headache post-operatively without recurrence on 1-month follow up. This case is unusual in that the patient presented without any known neurologic history or prior intracranial infections. It became apparent at the time of surgery that chronic obstruction of the bilateral foramina with collapse of the third ventricle had developed, and the safest durable treatment for him was septostomy and cerebrospinal fluid (CSF) shunt placement.

The aim of this article is to discuss the importance of staged surgeries when approaching atypical central neurocytoma in children. Also, we show the preoperative embolization of the lesion as a maneuver to reduce the intraoperative bleeding. Central neurocytomas represent less than 0.5% of all intracranial tumors, and atypical central neurocytomas usually have unfavorable outcome, with high recurrence rate. The intraventricular location is frequent, with a predilection for the lateral ventricles. When completely resected, these lesions have a good prognosis. We report a case of a 12-year old male patient that presented with a history of headache for about 6 months, which worsened for 1 week prior to admission. Magnetic resonance imaging (MRI) brain showed a massive lesion occupying both lateral ventricles. He underwent a microsurgical treatment of a highly vascularized lesion, but the perioperative bleeding required interruption of the surgery. Thus, a preoperative embolization was able to occlude most arterial feeders and allowed subtotal resection in a second surgery. The patient had complete neurological recovery despite immediate post-operative deficits, and the histopathology was suggestive of atypical neurocytoma. Two-stage surgery with preoperative adjuvant embolization is a feasible strategy for treatment of large central neurocytomas in children., (© 2020. Belgian Neurological Society.)

Cavum septum pellucidum (CSP) and cavum vergae (CV) cysts are commonly found incidentally. They are usually asymptomatic but may present with symptoms related to obstructive hydrocephalus. There is no consensus about the management of symptomatic CSP and CV cysts. We present, to the best of our knowledge, the first systematic review of the different treatment options for symptomatic CSP and CV cysts. We conducted a literature review using PubMed database, searching for cases of symptomatic CSP and CV cysts managed surgically, and published until April 2019. Preoperative characteristics, surgical procedure, and postoperative outcome were analyzed using SPSS® software (Statistical Package for Social Sciences, IBM®). We found 54 cases of symptomatic CSP and CV cysts managed surgically (34 males, 20 females, 1.7/1 male to female ratio). Mean age was 24.3 ± 20.1 years. The most common presentation was headaches (34 patients, 62%), followed by psychiatric symptoms (27 patients, 49.1%). Preoperative radiological hydrocephalus was present in 30 patients (54.5%). The most common surgical procedure was endoscopic fenestration (39 patients, 70.9%), followed by shunting (10 patients, 18.2%), open surgery (3 patients, 5.5%), and stereotactic fenestration (1 patient, 1.8%). Complete resolution of symptoms was achieved in 36 patients (65.5%) and partial resolution in 7 patients (12.7%), and symptoms were unchanged in 2 patients. The present review suggests that surgical treatment could provide resolution of the symptoms in most of the cases, regardless of the procedure performed. Although mean follow-up was short among the studies, recurrence rate was low., (© 2020. The Author(s).)

Background: Symptomatic cysts of the septum pellucidum (CSP) are extremely rare in children and surgical indications are not well defined. A very careful clinical and neuroradiologic evaluation is necessary to consider a patient for surgical indication., Methods: We present a surgical series of 7 pediatric patients. Clinical and radiological features of the patients, including clinical presentation, previous treatment, pre, and post-operative MRI, immediate postoperative, neuropsychiatric assessment, and outcomes were reviewed., Results: There were 5 males and 2 females (mean age 8 yrs). Five patients presented a history of severe intermittent headaches, two of them were admitted with acute symptoms of raised intracranial pressure. One patient presented Epilepsy and ADHD and one patient had severe psychosis. Overall, psychiatric disorders were diagnosed in six patients, three patients had Intellectual Disability (ID). In all cases, the cyst presented a ballooning feature, with a mean volume of 18,36 cm3 (range 10,62-28,5) and significant lateral bulging of both layers. All were operated on endoscopically without complications. After surgery, a very significant decrease in cyst volume was observed (mean volume 5,68 cm3; range 3,18-10,1) with complete disappearance of the ballooning aspect. Headaches resolved in all patients. In two patients operated in emergency papilloedema and vision improved in the first week after surgery. No recurrence of the cysts was noted during follow-up in all patients., Conclusions: CSP may be associated with behavioral or psychiatric problems also in children. Neuroendoscopic surgery is a safe and effective therapeutic modality to treat CSP presenting with symptoms and signs of intracranial hypertension with good clinical results., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Third ventricle cavernous malformations (CMs) associated with ventriculomegaly and obstructive hydrocephalus are quite rare in patients. Preoperative surgical planning can be challenging due to the lesion's non-specific appearance on CT and magnetic resonance imaging that can mimic other intraventricular pathologies, such as a colloid cyst. Management of these lesions can be varied in the setting of obstructive hydrocephalus., Case Description: The patient is a 78-year-old woman who first presented to her primary care provider with balance difficulties and inability to ambulate on her own. She also had bladder incontinence and progressive, severe headaches. Imaging of the brain demonstrated entrapment of the right lateral ventricle and obstructive hydrocephalus due to a lesion in the third ventricle obstructing the right foramen of Monro, thought to be a colloid cyst. A right frontal neuroendoscopic approach with direct visualization, however, confirmed a third ventricle CM. A septal pellucidum fenestration was performed to restore cerebrospinal fluid communication and no resection of the lesion was performed. The patient recovered well after the operation and at clinical follow-up reported no headaches and was walking well without a walker and with no neurological deficits., Conclusions: A third ventricle CM was discovered after a neuroendoscopic approach for resection of a presumed colloid cyst in a patient with obstructive hydrocephalus. A neuroendoscopic septostomy was performed to treat the obstructive hydrocephalus and no resection was attempted. The patient suffered no complications and is at her neurologic baseline with no deficits., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Rosette-forming glioneuronal tumor (RGNT) is a rare tumor entity which has been reported mainly occurring in the fourth ventricle. It has been described as a benign lesion with limited extension into surrounding structures, including the cerebellar vermis, midbrain, and cerebral aqueduct. More recently, few cases involving also other midline structures have been documented as well. Here, we report about diagnosis and treatment of RGNT in the septum pellucidum in a pediatric patient which has not been described previously. A 7-year-old boy had a 3-week history of headache. Magnetic resonance imaging showed a solid mass in the septum pellucidum accompanied by hydrocephalus. The tumor was resected via a transcortical approach. Histological examination revealed the typical findings of a RGNT. At 2-year follow-up, there was no tumor recurrence, and clinical outcome was unremarkable. RGNT has to be considered in the differential diagnosis of pediatric midline tumors also outside of the fourth ventricle. Surgical resection is the first-line therapy which may result in beneficial outcome in the long term. The role of adjuvant therapy needs further definition since due to the rarity of this tumor entity, available data is very limited.

Colloid cysts are uncommon, intracranial lesions frequently arising from the anterior aspect of the third ventricle. Rarely a cyst presents greater than 30 mm diameter as a giant colloid cyst. This case reports a patient with a giant colloid cyst occupying a cavum septum pellucidum et vergae. The clinical and operative significance of this anatomical variation is discussed and the giant colloid cyst literature reviewed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background and Importance: Cavum septum pellucidum (CSP) and cavum vergae (CV) cysts are common incidental findings on imaging studies. However, they may rarely present with symptoms related to the obstruction of the foramen of Monro by the cyst leaflets. There is no consensus regarding the management of symptomatic CSP and CV cysts. We present an original transcavum interforniceal endoscopic fenestration technique. The step-by-step surgical procedure and two illustrative cases are presented., Clinical Presentation: A 31-yr-old male and a 24-yr-old woman presented with symptomatic CSP and CV cysts. For both patients, neuronavigation was used to plan the procedure. An endoscope was introduced into the cyst through a right frontal burr-hole. After an examination of the endoscopic anatomy, a communication between the cyst and the third ventricle was performed using an endoscopic forceps. In both cases, directly after the fenestration, cerebrospinal fluid (CSF) passed through the communication, and the collapse of the cyst was appreciated. Symptoms were relieved in both patients, and neuropsychological assessment improved. Postoperative imaging showed a reduction in the cyst bulge, and patent foramen of Monro., Conclusion: Endoscopic fenestration of CSP and CV cysts to the third ventricle through an interforniceal navigated approach is a feasible and efficient surgical procedure. Theoretical advantages include a single tract through noneloquent brain, a perpendicular trajectory to the membrane for fenestration, and a large CSF space beyond the fenestration point., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Cysts of the septum pellucidum (CSP) are usually asymptomatic; however, in some cases they can begin expanding and cause neurological deterioration. The mechanism leading to the formation of an expanding cyst of the septum pellucidum (ECSP) is not known. Based on observations made during endoscopic treatment of ECSP we analyzed intraoperative findings in respect to cyst formation mechanism and treatment prognosis. A group of 31 patients was studied. Only cases with bulging cyst walls occupying the frontal horns observed on imaging studies were included. The main symptom was a severe, intermittent headache. In three cases short term memory deficits were diagnosed. In one case papilloedema was observed. All patients underwent endoscopic fenestration of the ECSP. There were no cases of cyst reocclusion during a follow-up period of 1-14 years (mean 6.2 years). In 30 cases headaches resolved completely and in one case its intensity was significantly smaller. There was one case of postoperative hemiparesis. In all but two cases the thin, translucent region in the anterior part of the cyst floor was found. In the region small fissures and in three cases choroid plexus were observed. Endoscopic fenestration is the efficient treatment for ECSP. ECSP is formed on the basis of not completely closed, developmental communication of the cyst with other fluid spaces. The communication is opened by transient elevation of intraventricular pressure, and acts as a valve leading to fluid accumulation among the walls of the previously asymptomatic cavum septum pellucidum.

Objective: To review and systematize literature data on the incidence of cysts of septum pellucidum, cavum vergae and cavum veli interpositi, their clinical manifestations, indications for surgical treatment and optimal surgical approach., Material and Methods: An analysis included 72 manuscripts devoted to epidemiology, pathophysiology, clinical symptoms and results of surgical treatment of brain cysts. Case reports, series of cases, reviews and original studies were analyzed., Results: Septum pellucidum cavity is always formed throughout an embryogenesis and persists in 20.34% of adults. Cavum vergae is observed in 2.32% of adults. Cyst of septum pellucidum is detected in 0.04% of adults. Analysis of 368 cases of cysts of septum pellucidum, cavum vergae and cavum veli interpositi has shown that clinical picture consists of headache (50% of cases), convulsive syndrome (23.6%), reduced intelligence (20.1%), behavioural disorders (15.8%), dizziness, nausea and vomiting (10.9%). Hydrocephalus occurs in 16.6% of cases. Endoscopic wall fenestration is preferred for cyst management., Conclusion: Brain cysts are rare and characterized by non-specific clinical manifestations. Symptomatic cyst is an indication for surgical treatment. Surgical treatment usually ensures regression of symptoms and low risk of complications.

Background: Rosette-forming glioneuronal tumors (RGNTs) with multifocal growth throughout the ventricular system are extremely rare, and only 1 case of RGNT with dissemination limited to supratentorial ventricles has previously been reported. Recent evidence based on molecular data suggest that low-grade glioneuronal tumors (GNT) involving the septum pellucidum and the lateral ventricles, with either dysembryoplastic neuroepithelial tumor-like or RGNT-like features, may belong to a neuropathologic entity distinct from cortical dysembryoplastic neuroepithelial tumor and "typical" fourth ventricle RGNT, respectively. Given their rarity, the classification of these neoplasms is still uncertain and their clinicopathological and radiological aspects are only partially known., Case Description: A 24-year-old male presented a GNT with RGNT-like morphological features centered in the septum pellucidum with multifocal masses occupying the lateral ventricles and the third ventricle with extraventricular infiltration of the frontal lobe. The patient underwent subtotal resection and 4 years follow-up. The clinicopathological and radiological features of the neoplasm are discussed., Conclusions: Advanced magnetic resonance imaging (magnetic resonance spectroscopy and perfusion-weighted imaging) may provide valuable information in the differential diagnosis between rare GNTs and other more frequent intraventricular neoplasms. In the present case, the enhancing remnant portion of the tumor showed remarkable contrast enhancement variability during the follow-up with slow in situ progression. However, available data suggest that spontaneous contrast enhancement "fluctuations" over time in RGNT may not represent a reliable indicator of tumor behavior., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Cysts of the Cavum septi pellucidi (CSP), cavum vergae (CV) and cavum veli interpositi (CVI) are anterior midline intracranial findings which are typically incidental - only rarely do we encounter symptomatic cysts of this type. Only a quite small number of these cysts series have been published, controversies regarding optimal management still exist., Patients and Methods: This is a retrospective study of 10 patients treated at 2 clinics between 2002-2018. 9 patients underwent surgery and 1 is under long-term monitoring. Apart from demographic data, the study analyzed symptoms, cyst size and progression over time, ventricle size, complications, and treatment modality., Results: CSP with CV was found in 8 cases with 1 case each of CSP and CVI. The study comprised 6 men and 4 women, including 4 children. The mean follow-up time was 43.4 months. The average cyst size was 20.4 mm in CSP and 19.8 mm in CV; the CVI was 33 mm. Headache was most commonly reported (70%) followed by behavioral disturbance (30%). Disturbance in memory, psychomotor development, school performance, visual acuity, and vomiting was variously noted in 20%. The prevailing symptom was headache in adults and behavioral and autonomic disturbance in children. Postoperatively, cysts had reduced by an average of 44.3% while the ventricles remained unchanged. Symptoms resolved in all cases with residual problems in patients presenting with memory loss. No complications were noted., Conclusion: Endoscopic fenestration is the method of choice in the treatment of symptomatic midline cysts. We recommend that any further research focuses on precisely establishing their clinical presentation, particularly neuropsychological symptoms., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Cavum septi pellucidi (CSP) are benign developmental cystic midline cavities that are located between the lateral ventricles through the foramina of Monro. CSP are usually asymptomatic and have no cerebrospinal fluid (CSF) flow. Although their incidence is increased in association with head trauma, as well as psychiatric and behavioural disorders, this increase seldom causes disease. Herein, we discuss the case of a toddler who presented with episodic headaches for 6 weeks with associated vomiting triggered by strenuous activity. His neurological examination was normal. His MRI brain scan revealed large cavum septum pellucidum with obstructive hydrocephalus. He underwent endoscopic fenestration of the cyst with resolution of both hydrocephalus and the symptoms. Although CSP are generally asymptomatic, in rare situations, as in our illustrative case, they may cause obstructive hydrocephalus that requires urgent attention. CSF flow studies are helpful in confirming the diagnosis., (© 2019 S. Karger AG, Basel.)

Introduction: Cavum septi pellucidi (CSP) cysts have a very low incidence (0.04%). Symptomatic patients usually present aspecific symptoms. For this reason, the management of these patients is still debated., Materials and Methods: We selected the case of a ten year old patient, with a clinical history of frontal morning headaches and difficulty in concentration. Brain MRI documented a septum pellucidum cyst and a moderate biventricular dilation. We submitted the case, and a questionnaire concerning indications to surgery and management options to an international group of 54 pediatric neurosurgeons, analyzing the results and comparing them with the current literature., Results: The majority of the participants (50%) indicated as appropriate at the early stage only a clinical observation. In case of persistence of clinical symptoms, 58% opted for intracranial pressure (ICP) monitoring, which, if raised, was considered by 91% as an adequate indication to proceed with surgical treatment. A total of 98% of the participants indicated endoscopic fenestration of the cyst as the preferred surgical strategy., Conclusions: The management of symptomatic patients with CSP cyst is controversial. Our results suggest that in most of the patients with aspecific symptoms, clinical observation and eventually ICP monitoring are adequate to identify patients for surgery.

Intraventricular rupture of a colloid cyst is a rare phenomenon and has been proposed as a mechanism for sudden death in patients with colloid cysts. Imaging of a colloid cyst during rupture has been described in only one other instance. The authors report a highly unusual case of a 53-year-old man who presented with acute onset headaches and imaging findings of hydrocephalus caused by a colloid cyst originating from the septum pellucidum and superior surface of the roof of the third ventricle. Interestingly, the colloid cyst revealed imaging signs of intraventricular rupture characterized by a tail-like drainage of cystic contents into the occipital horn of the lateral ventricle. The patient was surgically treated with a craniotomy and transcallosal approach to the colloid cyst, where it was noted that the cyst wall was spontaneously open. This rare case highlights unique imaging findings of a rare event in an infrequent pathology confirmed with intraoperative microscopy. The authors further document the process of cyst rupture and speculate on its pathomechanisms.

Background: Cavum septum pellucidum (CSP) and cavum vergae are actually fluid-filled, generally communicating midline cavities located between the third ventricle and corpus callosum. There have been various reports of their association with many behavioral and psychiatric disorders. Infrequently, they have been associated with an obstructive hydrocephalus-like picture. Although the structure and management of CSP has long been known, it has been an enigma as far as functional significance and management indications are concerned. The authors of this article try to analyze the significance of a persistent cavum and involvement of the same entity in varied presentations ranging from an incidental imaging finding to acute hydrocephalus, and propose a possible implication on the present surgical intervention paradigm., Purpose: To assess the surgical outcome of fenestration of a CSP cyst., Methods: Retrospective analysis of 3 patients who underwent endoscopic fenestration for CSP with obstructive hydrocephalus between 2012 and 2014 was done, and data were analyzed for symptomatic clinical improvement in particular behavior., Results: Pre- and postoperative brain MRI showed a significant decrease in the size of the cyst as well as the ventricles. There were no recurrences during follow-up. All of the patients improved., Conclusions: (1) Endoscopic fenestration of symptomatic CSP cysts is a safe treatment option. (2) Neurocognitive assessment is essential in the evaluation and outcome assessment of CSP., (© 2017 S. Karger AG, Basel.)

We review our experience with four patients who presented to our Medical Center from 2005-2015 with adult idiopathic occlusion of the foramen of Monro (FM). All patients underwent CT scanning and MRI. Standard MRI was performed in each patient to rule out a secondary cause of obstruction (T1-weighted without- and with gadolinium, T2-weighted, fluid-attenuated inversion recovery [FLAIR] and diffusion-weighted imaging [DWI] protocols). When occlusion of the FM appeared to be idiopathic, further high-resolution MRI with multiplanar reconstructions for evaluation of stenosis or an occluding membrane at the level of the FM was performed (T1-weighted without- and with gadolinium, T2-weighted 3D turbo spin-echo). Occlusion of the FM was due to unilateral stenosis and septum pellucidum deviation in two patients, to an occluding membrane in one, and to bilateral stenosis in one patient. Urgent surgical intervention is mandatory when there are signs of increased intracranial pressure while asymptomatic patients may be managed conservatively. In this patient series, truly bilateral stenotic obstruction of the FM was best managed with ventriculoperitoneal shunt and patients with membranous obstruction or unilateral stenosis with septum deviation were treated endoscopically., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Cadaveric surgical simulation carries the advantage of realistic anatomy and haptic feedback but has been historically difficult to model for intraventricular approaches given the need for active flow of CSF. This feasibility study was designed to simulate intraventricular neuroendoscopic approaches and techniques by reconstituting natural CSF flow in a cadaveric model. In 10 fresh human cadavers, a simple cervical laminectomy and dural opening were made, and a 12-gauge arterial catheter was introduced. Saline was continuously perfused at physiological CSF pressures to reconstitute the subarachnoid space and ventricles. A neuroendoscope was subsequently inserted via a standard right frontal bur hole. In 8 of the 10 cadavers, adequate reconstitution and endoscopic access of the lateral and third ventricles were achieved. In 2 cadavers, ventricular access was not feasible, perhaps because of a small ventricle size and/or deteriorated tissue quality. In all 8 cadavers with successful CSF flow reconstitution and endoscopic access, identifying the foramen of Monro was possible, as was performing septum pellucidotomy and endoscopic third ventriculostomy. Furthermore, navigation of the cerebral aqueduct, fourth ventricle, prepontine cistern, and suprasellar cistern via the lamina terminalis was possible, providing a complementary educational paradigm for resident education that cannot typically be performed in live surgery. Surgical simulation plays a critical and increasingly prominent role in surgical education, particularly for techniques with steep learning curves including intraventricular neuroendoscopic procedures. This novel model provides feasible and realistic surgical simulation of neuroendoscopic intraventricular procedures and approaches.

Introduction: The cavum of the septum pellucidum occurs in up to 15% of adults and is considered as an anatomical variant. How- ever, some patients reveal symptoms which are associated with the evolution from the cavum in the form of a cyst of the septum pelludum. Cyst incidence is much lower. The pathomechanism and risk factors of such changes are not fully understood. Among the theories for the formation of the cyst, most attention is given to the hypothesis of the mechanism of the valve in the flow of cerebrospinal fluid. However, this statement can be validated only on the basis of direct observation, which can be made in vivo only with the help of the endoscopic method. The aim of this study was to describe the clinical and radiological features coexisting with the expanding cysts of the septum pellucidum. The research also included considerations on the pathogenesis of the expanding cysts of the septum pellucidum, as well as the evaluation of the intraoperative endoscopic image., Material and Methods: The study included 27 patients of the Department of Neurosurgery Pomeranian Medical University in Szczecin, diagnosed with an expanding cyst of the septum pellucidum, who underwent neurosurgery treatment. The patients' clinical and radiological symptoms were evaluated before and after surgical intervention. Analysis of the intraoperative endoscopic images was also performed., Results: The most common clinical symptoms in patients before surgery were similar: headache, dizziness, nausea and vomiting, advanced nervous functions disorders, and visual defects. In most cases the symptoms resolved after surgical treatment, which proves their association with the occurrence of cysts. Significant differences in radiographic measurements before and after surgery where also noted, which allowed the determination of clinical and radiological criteria for the diagnosis of expanding cysts of the septum pellucidum, and intravital intraoperative findings allowed direct proof of the cyst's filling mechanism. The obtained results allowed us to prove the hypothesis of the valve mechanism as the main factor causing the symptoms in patients with expanding cysts of the septum pellucidum, and to determine the components of the syndrome of the septum pellucidum cyst. They confirmed the validity of the selection of surgical treatment using an endoscope. Furthermore, changes in the geometry of the structures of the central nervous system observed in the analysis of radiological images before and after surgery made further research on the dynamics of this anatomical area in patients with expanding cysts of the septum pellucidum reasonable.

Adult idiopathic occlusion of the foramen of Monro (AIOFM) is a rare condition, with only few cases described in the modern literature. We propose that AIOFM may result from unilateral or bilateral occlusion of Monro foramina, as well as from progression of a monolateral hydrocephalus. Different surgical strategies may be required for effective treatment according to the type of occlusion. To date, only 12 cases of AIOFM have been reported in the literature. We report the cases of two patients, aged 20 and 47 years respectively, who presented with intracranial hypertension secondary to bilateral ventricular dilatation due to obstruction at the level of the foramen of Monro. Both patients were successfully treated with endoscopic fenestration of the primarily obstructed foramen of Monro and, in one patient, fenestration of the septum. We propose that septum pellucidum displacement could play a role in the occlusion of the second foramen of Monro. AIOFM can, therefore, result also from unilateral stenosis of Monro. The difference in AIOFM (i.e. unilateral vs bilateral) will be useful in guiding the most suitable surgical approach in this rare condition.

Colloid cysts are common cysts are often located in the anterior third ventricle and septum pellucidum location is extremely rare. Cysts in septum pellucidum can be missed at surgery because of their unusual location. We describe three patients with colloid cysts in the septum pellucidum, with two in the cavum septum pellucidum. Various surgical implications of this unusual location are enumerated.

Background: Choroid plexus papilloma (CPP) in the third ventricle is a rare benign intracranial tumor., Methods: We report 3 pediatric cases of CPP in the third ventricle. The lesions were totally removed by a different surgical approach in each case., Results: When remarkable hydrocephalus is present, the transcortical approach is easier to perform, but may expose the patient to epilepsy and subdural effusion postoperatively. The transcallosal approach offers direct exposure of the ventricle system with minimal risk of cortical damage. The transcallosal-transforaminal approach with posterior enlargement of the foramen of Monro along the choroidal fissure provides a direct trajectory into the third ventricle through the natural cleft. The transcallosal-interforniceal approach does not depend on the size of the foramen of Monro, but it carries a risk for damage to the both fornices. The midline plane of the septum pellucidum and the forniceal columns in children are sometimes easily identifiable and separable, and in such cases the transcallosal-interforniceal approach appears to be a safe route for tumors extending to the posterior third ventricle. The interforniceal approach should be reserved for lesions that cannot be removed safely via the transforaminal approach., Conclusions: Young children have a small total blood volume and fragile cardiovascular status. Therefore, it is critical to preserve the venous system and to ligate the feeding artery before extirpation of the tumor. The surgical approach to the third ventricular CPPs should be tailored to individual children based on tumor size, location, and vascularity., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: The aim of this study was to noninvasively visualize whether cerebrospinal fluid (CSF) compartments are in communication., Case Description: An enlarging cavum septi pellucidi (CSP) produced progressive hydrocephalus following subarachnoid hemorrhage. We questioned what were the dynamics of CSF flow that led to enlargement of the CSP., Conclusion: With this case report, we show the usefulness of a newly described magnetic resonance imaging time-spatial labeling inversion pulse technique to establish that an enlarging CSP was the cause of progressive hydrocephalus and that the hydrocephalus was successfully endoscopically treated when the CSP was fenestrated into the ventricular system, establishing communication between the two CSF compartments., (Copyright © 2013 Elsevier Inc. All rights reserved.)

INTRODUCTION. Intracranial arachnoids cysts are considered benign developmental anomalies that occur within the arachnoid membrane and generally contain clear and colourless fluid resembling cerebrospinal fluid. The prevalence of these cysts is higher in the first two decades of life, and the incidence is widely quoted as approximately 1% of all space-occupying intracranial lesions. Arachnoids cysts in the elderly person are a rare occurrence. We report the unusual presentation of a woman with an intraventricular arachnoid cyst treated with endoscopic technique. CASE REPORT. A 75-year-old woman presented with progressive hemiparesis of two years duration. Cranial MR imaging showed a right parieto-occipital intraventricular cyst with local mass effect and moderate dilatation of lateral ventricles. A right-sided burr hole was made and the arachnoids cyst was reached and cysto-ventricle shunting was realized. This was followed by a septum pellucidum fenestration. There were no complications during the surgery and the patient presented no symptoms at time of discharge. CONCLUSIONS. The neuroendoscopic approach to intraventricular arachnoid cysts was effective with few complications.

Objectives: Monoventricular hydrocephalus (MH) is a rare condition in which the site of obstruction is located around one of the interventricular foramen. In this paper, the authors offer their experiences in the neuroendoscopic management of this uncommon type of hydrocephalus., Patients and Methods: The authors retrospectively reviewed 12 neuroendoscopic procedures performed between July 2003 and June 2011 with MH. Clinical and radiological charts were reviewed and analysed., Results: The operative course is a simple and successful procedure, and the postoperative complaints are mild. The postoperative radiological findings showed maintenance of ventricular enlargement in four cases and a significant decrease in enlargement in eight patients. However, upon shifting of the septum pellucidum, the periventricular transudation disappeared in all patients., Conclusions: Fenestration of the septum pellucidum by neuroendoscope is the best treatment for patients with monoventricular hydrocephalus. The approach for fenestration of the septum pellucidum is based on the experience of the neurosurgeon and the preoperative planning., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: Traditional surgical treatments for this rare disease include open surgical procedures and ventriculoperitoneal shunting. In 1995, endoscopic fenestration was first applied to treatment of cysts of the septum pellucidum (CSP). However, cyst fenestration generally takes a bilateral approach by making two burr holes leading to two fenestrations in the lateral walls of the cyst. Some disadvantages are related to bilateral fenestration. So far, there is no consensus on the surgical indications, the endoscopic approaches, and techniques for CSPs. Based on our experience with 14 cases of symptomatic CSP treated with neuronavigation-assisted endoscopic unilateral cyst fenestration via a single burr hole, we discuss the operative indications and the utility of endoscope-assisted techniques in combination with neuronavigation., Methods: 14 patients underwent endoscopic CSP fenestration via a right frontal approach using a rigid endoscope and neuronavigation. Neuronavigation helped locating optimal skin incision, puncture point, optimal operation trajectory, and real-time operation monitoring. Postoperatively, a follow-up study on the 14 patients was performed., Results: The follow-up period ranged from 6 months to 2 years. Postoperatively, the mass effect of the cysts and the self-reported symptoms disappeared immediately. In 7 patients with papilledema, the optic fundus examinations showed that papilledema improved. The computerized tomography (CT) or magnetic resonance imaging (MRI) scans showed significant decrease in the cyst size and no recurrence during the follow-up. In 2 patients with accompanying hydrocephalus, the hydrocephalus disappeared., Conclusion: The results after uni- and bilateral CSP fenestration show no significant difference. Avoiding damage of contralateral tissue, the surgical trauma in unilateral fenestration is less than in bilateral fenestration. Furthermore, the unilateral approach shortens the operation time. We believe that unilateral cyst fenestration is a better therapeutic option in symptomatic CSP., (Georg Thieme Verlag KG Stuttgart · New York.)

Objective: Primary central nervous system non-Hodgkin lymphoma (PCNSL) is a malignant lymphoma limited to the cranial-spinal axis in the absence of systemic lymphoma. Historically, PCNSL accounts for fewer than 5% of all cases of primary intracranial neoplasms. PCNSL is rare in immunocompetent young adults. Although the prognosis for PCNSL is poor, approximately 20%-30% percent of cases achieve a cure., Methods: We report two cases of PCNSL originating in the ventricle in otherwise healthy immunocompetent young adults., Results: A 27-year-old man presented with 10 days of nausea, vomiting, and headache and was found to have a large intraventricular mass emanating from the choroid plexus with resultant hydrocephalus. He underwent placement of external ventricular drain and systemic and intrathecal chemotherapy for cytologically proven PCNSL. A 31-year-old pregnant woman presented with headaches, vision difficulties, and ataxia and was found to have a septum pellucidum mass. She underwent craniotomy and subtotal resection of the mass with subsequent systemic therapy and whole brain radiation for treatment of PCNSL., Conclusions: To our knowledge, this is the first report of primary CNS lymphoma of the choroid plexus and septum pellucidum in otherwise healthy, immunocompetent young adults., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: The management of complex hydrocephalus is challenging. There is no consensus of the best treatment for isolated fourth ventricles, arachnoid cysts, and multiloculated hydrocephalus, although the avoidance of multiple shunts is desirable. We reviewed our experience with the use of endoscopic techniques to simplify complex multicompartmental hydrocephalus to determine its efficacy and safety., Methods: We performed a retrospective study of 114 consecutive adults and children undergoing endoscopic management of hydrocephalus by a single surgeon. The type of hydrocephalus and endoscopic procedure performed were recorded. The management algorithm for simplification of complex hydrocephalus is reviewed. All patients were followed up in the office or by telephone., Results: A total of 143 endoscopic procedures were performed on 114 patients with a mean age of 4.4 years (4 weeks to 32 years). The endoscopic procedures performed included cyst fenestration, septum pellucidotomy, endoscopic third ventriculostomy, aqueductal plasty with and without stent, and removal of cystercicotic cysts. Twenty-two (19.3%) patients had planned staged endoscopic procedures. Mean follow up was 65 months (range 33-122 months). Eighty-two (72%) patients were reduced to 1 shunt, shunt independence was achieved in 32 (28%) patients, and only 8 (11%) patients required shunt revision in the follow-up period., Conclusions: Endoscopic simplification of complex hydrocephalus enables dependence on only a single shunt in the majority of patients, and a significant proportion achieve shunt independence. Endoscopic management should be considered before the placement of a second shunt, and some cases require staged endoscopic procedures to adequately communicate multicompartmental hydrocephalus., (Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.)

In the original description, rosette-forming glioneuronal tumors (RGNTs) were restricted to the fourth ventricle and/or posterior fossa. Here, we first report an unusual case of RGNT centered in the septum pellucidum and associated with multiple masses occupying the wall of the bilateral lateral ventricles and the third ventricle. No mass was found in the fourth ventricle. Histological and immunohistochemical examination revealed that the tumor presented biphasic differentiation characterized by predominantly neurocytic rosettes and pilocytic astrocytoma-like components with obvious microvascular proliferation. Chromosome 1p/19q deletions and isocitrate dehydrogenase 1 and 2 (IDH1/2) mutations were not identified. Because this case exhibited a worrisome growth pattern, further studies and long-term follow-up are needed to determine the true nature of these tumors., (© 2011 Japanese Society of Neuropathology.)

Background: Cavum septum pellucidum (CSP) cysts are rare lesions which are frequently asymptomatic. Some clinical findings may be associated with CSP cysts, such as headache and other symptoms of increased intracranial pressure, neurological deficit, and mental status changes. There is still controversy in the management of symptomatic cases, especially in children. The main difficulty is to establish a correlation between symptoms and the cyst. When indicated, the treatment is essentially surgical, and the ideal operative technique is also a matter of debate., Case Report: We present a case of a 14-year-old boy with a symptomatic CSP cyst who was successfully treated by neuronavigation-assisted neuroendoscopy with a bilateral fenestration. A literature review is provided with regard to clinical presentation, treatment, and outcome in children., Conclusion: The treatment is considered whenever there is an association of a CSP cyst on imaging studies and symptoms attributable to the obstruction of the cerebrospinal fluid flow or direct compression of surrounding structures by the cyst. Endoscopic fenestration is a less invasive and highly effective technique, and is currently the treatment of choice for such lesions in children.

Corpus callosotomy offers useful palliation for selected patients with medically intractable seizures, particularly those with uncontrolled and disabling drop attacks. Here the authors present their technique for performing a corpus callosotomy that allows for complete sectioning of the callosum while avoiding entry into the lateral ventricles. The anatomical basis for the technique is the presence of a definable cleft just ventral to the corpus callosum in the midline, formed by the fusion of the two laminae of the septum pellucidum. This small cleft is typically present even in the absence of a cavum septum pellucidum on MR imaging. The authors have found that dividing the body of the corpus callosum by exploiting the cleft of the septum pellucidum in the absolute midline is a simple and expeditious way to perform a callosotomy without entering the lateral ventricles.

Introduction: Spontaneous regression of pilocytic astrocytoma after incomplete resection is well recognized, especially for cerebellar and optic pathway tumors, and tumors associated with Neurofibromatosis type-1 (NF1). The purpose of this report is to document spontaneous regression of pilocytic astrocytomas of the septum pellucidum and to discuss the possible role of cannabis in promoting regression., Case Report: We report two children with septum pellucidum/forniceal pilocytic astrocytoma (PA) tumors in the absence of NF-1, who underwent craniotomy and subtotal excision, leaving behind a small residual in each case. During Magnetic Resonance Imaging (MRI) surveillance in the first three years, one case was dormant and the other showed slight increase in size, followed by clear regression of both residual tumors over the following 3-year period. Neither patient received any conventional adjuvant treatment. The tumors regressed over the same period of time that cannabis was consumed via inhalation, raising the possibility that the cannabis played a role in the tumor regression., Conclusion: We advise caution against instituting adjuvant therapy or further aggressive surgery for small residual PAs, especially in eloquent locations, even if there appears to be slight progression, since regression may occur later. Further research may be appropriate to elucidate the increasingly recognized effect of cannabis/cannabinoids on gliomas.

Background: Endosopic septum pellucidotomy is used for treating patients with unilateral and specific types of bilateral hydrocephalus. The ideal location for septostomy is controversial; however, an avascular region is preferred., Objective: As the septal veins (SVs) are viewed only from one side, we studied the symmetry of the SVs in an attempt to define a safe area for septostomy., Methods: Sixteen cadaver brains were dissected. The septum pellucidum was exposed bilaterally and divided into 3 regions. SVs of both sides were evaluated according to number, size, distribution, and location relative to common markers on both sides., Results: Each side included 1 to 7 large veins (mean ± standard deviation, 2.3 ± 1.4), 0 to 3 small veins (2.05 ± 1.73), and a total of 2 to 7 veins (4.35 ± 1.53). Of the large veins, 88% were located in the anterior septal region (anterior to the foramen of Monro). Among the 10 brains that were extensively dissected, 90% had asymmetric SVs (either in the number of large veins or in the existence of any veins) in at least 1 of the septal regions, and 50% of brains had asymmetric SVs in the anterior region., Conclusion: Distribution of the SVs is asymmetric in most cases. We recommend septostomy be performed at the anterior area of the middle septal region, at the level of the foramen of Monro, mid-height between the corpus callosum and fornix. Careful evaluation of preoperative images and thorough coagulation at the septostomy site are essential to avoid injury to a contralateral large SV.

Tumors located within the third ventricle have some potential limitations during surgical approach. Generally speaking, it is impossible to reach the third ventricle without incision of any neural structure. We report a patient with choroid glioma in the anterior part of the third ventricle, and coincident cavum septum pellucidum (CSP) in whom we could remove the tumor gross totally without damaging any neurovascular structures. The tumor expanded the space between the rostrum of the corpus callosum and the column of the fornix and lifted up the floor of CSP. The transcavum-septum-pellucidum approach anterior to foramen of Monro was chosen to remove the anterior third ventricle tumor. We propose that the tumor had likely expanded within the above-mentioned space and elevated the floor of CSP thus increasing the anteroposterior diameter of the floor providing a feasible avenue to third ventricle making it feasible to pass through the enlarged space safely. Overall, cavum septum pellucidum provided a feasible route to approach the anterior third ventricle directly.

The authors present the case of an 11-week-old girl in whom hydrocephalus developed secondary to intermittent obstruction of the third ventricle by a choroid plexus cyst. The patient presented to the emergency department at the authors' institution with a 1-day history of projectile vomiting, lethargy, and dysconjugate gaze. Hydrocephalus was confirmed on head CT. During hospitalization, the symptoms resolved with a decrease in ventricular size. One week later, the patient again presented with similar symptoms, and MR images with 3D-constructive interference in steady state sequences revealed that a cyst was blocking the third ventricle. The patient subsequently underwent endoscopic fenestration of the cyst with resolution of hydrocephalus and symptoms. The authors present a unique description of the diagnosis of intermittent obstructive hydrocephalus caused by a third ventricular region choroid plexus cyst in an infant.

A choroid plexus papilloma is a rare CNS neoplasm arising from the neuroepithelial lining of the choroid plexus. A third ventricular location of a choroid plexus papilloma is rare compared with the more common sites in the lateral and fourth ventricles. Cystic choroid plexus papilloma represents an infrequent subtype that may present diagnostic ambiguity. The authors present a case of cystic choroid plexus papilloma within a cavum septum pellucidum that radiographically mimicked neurocysticercosis.