Technical aspects of fourth ventricle ependymomas in adults: how I do it.

BACKGROUND: Ependymomas in the fourth ventricle in adults are rare entity. Surgical treatment of adult ependymomas is the only treatment modality since no other effective alternative is available. Radical resection often means cure but it is hindered by the nature and location of the lesion. METHODS: Technical aspects of the fourth ventricle ependymoma surgery in adults are discussed. Anatomy of the area is provided with the step-by-step surgical algorithm. CONCLUSION: Radical resection of low-grade ependymoma with a detailed understanding of the anatomy in this area is vital considering the high effectiveness of the treatment and its excellent prognosis.

The Anterior Interhemispheric Transcallosal Approach to the Ventricles: How We Do It.

Intraventricular tumors of the lateral and third ventricles are relatively rare, accounting for 1-2% of all primary brain tumors in most large series [1-4]. They can be uniquely challenging to approach due to their deep location, propensity to become large before they are discovered, and association with hydrocephalus [5, 6]. The surgeon's goal is to develop a route to these deep lesions that will cause the least morbidity, provide adequate working space, and achieve a complete resection. This must be performed with minimal manipulation of the neural structures encircling the ventricles, avoiding functional cortical areas, and acquiring early control of feeding vessels [7, 8].

Fully Endoscopic Minimally Invasive Trans-Eyebrow Supraorbital Translaminar Approach to Third Ventricle Craniopharyngiomas: Technical Nuances and Stepwise Illustrative Description.

BACKGROUND: Traditional microsurgical approaches for addressing intraventricular craniopharyngioma provide limited access to the retrochiasmatic area and tumors with significant lateral or rostrocaudal extensions. Extended endoscopic endonasal approaches can effectively overcome many of limitations, yet they require a favorable working angle between the optic chiasm and pituitary gland, as well as the involvement of the third ventricle floor by the tumor. METHODS: Herein, the authors describe the surgical nuances of a keyhole technique for resecting third ventricle craniopharyngiomas via a fully endoscopic minimally invasive trans-eyebrow supraorbital translaminar approach (ESOTLA). A case description detailing the key surgical steps and application of the approach is provided, along with a series of cadaveric photographs to highlight the relevant anatomy and step-by-step dissection process. RESULTS: The patient is a 44-year-old man who presented with polyuria, low urine specific gravity, and panhypopituitarism. Brain magnetic resonance imaging revealed a solid-cystic heterogeneous-enhanced retrochiasmatic mass within the third ventricle, consistent with craniopharyngioma. A 1-stage ESOTLA was indicated based on the narrow pituitary-chiasm angle and the high functional status of the patient. Near-total resection was achieved, and no new postoperative neurologic or endocrine change was observed. Targeted therapy was implemented based on the histologic result, and the most recent surveillance magnetic resonance imaging showed no evidence of the residual tumor. CONCLUSIONS: By combining a keyhole approach with variable-angle endoscopic visualization through a smaller bony and soft tissue exposure, ESOTLA can provide enhanced illumination within the third ventricle, potentially addressing cosmetic concerns and limited exposure area/angle of freedom associated with its conventional microsurgical counterpart.

Suprasellar masquerader: Chordoid glioma.

BACKGROUND: Chordoid glioma is a rare well-circumscribed glial neoplasm arising in adults and predominantly affects females. Tanycytes of the third ventricle have been proposed as the cell of origin owing to its location. It is characterized by chordoid features with myxoid and inflammatory stroma and recurrent PRKCA p.D463H missense mutation. CASE REPORT: We present two cases (30-year-old female and 45-year-old male) with similar complaints of behavioral change and headache. Midline suprasellar homogeneously enhancing mass was seen on contrast-enhanced magnetic resonance imaging. Histopathology and immunohistochemistry was characteristic of chordoid glioma with cords and clusters of epithelioid cells arranged in a solid pattern. There were variable amounts of myxoid stroma and lymphoplasmacytic infiltrate. No mitosis, necrosis, or brain invasion was noted. The cells expressed strong diffuse positivity for glial fibrillary acid protein (GFAP) and weak nuclear thyroid transcription factor (TTF-1). Epithelial membrane antigen (EMA)and brachyury were negative. Subsequently, the lady underwent gross total excision and died soon after the operation. The male patient received radiotherapy and is currently doing well after 6 months of follow-up. CONCLUSION: The rare occurrence as well as the radiological and morphological overlaps in chordoid gliomas make them a true masquerader. Combination of GFAP and TTF-1 in the immunohistochemical panel can be useful in differential diagnosis. Mainstay of treatment is complete surgical excision, with adjuvant radiotherapy becoming increasingly important.

Resection of an Intraventricular Metastatic Tumor with Minimally Invasive Port Technique: 2-Dimensional Operative Video.

The use of minimally invasive port technology has been proposed as a safe method to reduce retractor-induced parenchymal injury, particularly for the resection of deep-seated lesions.1-6 A 69-year-old woman with a history of previous colon cancer surgery presented with gait disturbances and progressive headaches. Magnetic resonance imaging revealed a tumor involving the right ventricular atrium that appeared consistent with metastasis. A parieto-occipital craniotomy was performed on the basis of the preoperatively planned surgical trajectory (Video 1). After the dural incision, the arachnoid was opened down to the sulcus under visualization with microscope. Next, the ViewSite Brain Access system tubular retractor (VBAS; Vycor Medical Inc., Boca Raton, Florida, USA) was introduced toward the lesion under navigation guidance. Once the ventricular atrium was entered, the surface of the tumor came into view. It was coagulated and progressively debulked with ultrasonic aspirator. After the mass was adequately decompressed, a plane of dissection between the ependyma and the tumor could be developed with dynamic angulation of the port in order to allow better visualization. Finally, the tumor could be gently rolled away from the choroid plexus and removed. Meticulous hemostasis was achieved, and the tubular retractor was slowly removed. The patient recovered uneventfully without neurologic deficits on follow-up, and the postoperative magnetic resonance imaging evidenced a complete resection of the tumor. The video illustrates technical nuances and demonstrates the feasibility of minimal access port surgery for the resection of intraventricular lesions with low morbidity and mortality using microsurgical techniques. The patient consented to the publication of her image.

Clinical Results and Quality of Life After Transcortical Versus Transcallosal Resection of Adult Lateral and Third Ventricle Lesions: Long-Term Outcome.

BACKGROUND: Resection of intraventricular tumors can be achieved using 2 main operative approaches: transcallosal or transcortical. This study aims to describe preoperative and postoperative factors as well as quality of life (QoL) based on long-term results in these patients. METHODS: Patients underwent surgery of primary intraventricular lesions between 2007 and 2020 via a transcortical (group A) or transcallosal (group B) route. The main clinical parameters were completeness of resection, overall survival, surgical complications, postoperative neurologic deficits, and seizure rates. QoL was assessed using a modified questionnaire Short-Form 36 inventory. RESULTS: Forty patients (19 women and 21 men) met the inclusion criteria. Group A consisted of 26 patients (12 women and 14 men; median age 45.5 years ± 16.7 standard deviation) and had lower preoperative tumor volume (confounder) compared with group B (7 women and 7 men; age 50.0 ± 17.4 years). Gross total resection was achieved in 65% in group A and 71% in group B. Follow-up was 7.8 ± 3.9 years. New seizures/permanent neurologic deficits occurred in 27%/15% (group A) and 29%/29% (group B) and surgical complications in 23% of patients. Group B had a higher degree of memory impairment (21%) compared with group A (10%). QoL impairment was present in both groups mainly regarding physical role function and mental health index. CONCLUSIONS: Keeping in mind the limitations, transcallosal surgery was associated with a higher probability of neurologic deficits and memory impairment in our series. However, it had fewer surgical complications with similar gross total resection and seizure rates.

Cytological features of chordoid glioma: A case report with summary of prior published cases.

Chordoid glioma is an uncommon low-grade glioma and is a CNS WHO grade 2 tumour in the current WHO 2021 classification. Predominantly it is seen in the third ventricle and in young adults. Although the histological features of chordoid glioma are well documented, there is sparse literature describing its cytological features. Here we describe the squash cytological features of a case of chordoid glioma along with summary of prior published cases. The smears tend to be quite cellular, the cells show mild pleomorphism, anisonucleosis, and absent mitotic activity. The background shows a distinctive bluish myxoid stroma. It can be mistaken for high grade glioma on squash cytology.

Endoscopic endonasal approach to remove pediatric intraventricular tumors of the third ventricle.

PURPOSE: Pediatric intraventricular tumors of the third ventricle are among the most difficult-to-treat brain tumors. Recently, endonasal endoscopic surgery for suprasellar, third ventricle, and median clivus lesions has become the common procedure, and its indications are expanding to pediatric cases. We describe our strategy for endonasal endoscopic surgery for pediatric third ventricle tumors. METHOD: We report on surgical anatomies and our surgical procedures in detail, including case presentations. RESULT: Endoscopic endonasal surgery has the advantage of providing a wider view of the tumor site, hypothalamus, optic chiasm, and other critical structures. Good indications for the endoscopic endonasal approach for intra-third ventricular tumors are those arising from the floor of the third ventricle. In particular, craniopharyngioma, a typical pediatric suprasellar tumor, sometimes extends into the third ventricle, causing great operative difficulty. However, aggressive removal for long-term control while preserving memory and visual function is important. We perform surgery with a strategy of radically removing tumors without causing damage to visual or brain function, and we adopt the "4-hands technique by two neurosurgeons" in full endoscopic surgery to remove tumors safely and aggressively. CONCLUSION: We describe our strategy for endonasal endoscopic surgery for pediatric third ventricle tumors, especially those extending from the suprasellar region into the third ventricle, and present a representative case.

Granular cell tumor of the neurohypophysis presenting as a third ventricle mass.

Granular cell tumors of the neurohypophysis (GCT) are rare benign neoplasms belonging, along with pituicytoma and spindle cell oncocytoma, to the family of TTF1-positive low-grade neoplasms of the posterior pituitary gland. GCT usually present as a solid sellar mass, slowly growing and causing compressive symptoms over time, occasionally with suprasellar extension. They comprise polygonal monomorphous cells with abundant granular cytoplasm, which is ultrastructurally filled with lysosomes. Here we report the case of a GCT presenting as a third ventricle mass, radiologically mimicking chordoid glioma, with aberrant expression of GFAP and Annexin-A, which lends itself as an example of an integrated diagnostic approach to sellar/suprasellar and third ventricle masses.

Incidentally exploring natural course of a rare entity: representative case for rosette-forming glioneuronal tumors.

Rosette-forming glioneuronal tumors (RGNT) are extremely rare mostly benign tumors of the central nervous system, which are often studied for its histological aspects despite relatively small numbers of clinical especially radiological knowledge.Despite the increasing number of publications on different localizations and treatment protocols, the morphologic and temporal development process of this rare tumor entity is not clear. We were able to coincidentally observe the entire course of the tumor growth of a RGNT on subsequent MRI examinations in a typical case with mild clinical symptoms and no other neurological illnesses, thus possible clinical complications were prevented.

Transcallosal and endoscopic hybrid approach to a rare entity of pediatric intraventricular tumors-cribriform neuroepithelial tumor: a case report and literature review.

PURPOSE: Cribriform neuroepithelial tumor (CRINET) is a provisional category of intraventricular tumors, sharing similarities with AT/RTs, and there is a lack of data about its pathology, prognosis, and surgical approaches in the literature. We have been challenged to describe the surgical approach to a rare case of CRINET and describe the intraoperative features since none has been described before. Surgical resection and chemotherapy hold a great importance of favorable prognosis. METHODS: Twenty-month-old male with intraventricular tumor underwent transcallosal intraventricular tumor resection and endoscopic intraventricular second look stages. The tumor was initially considered choroid plexus carcinoma and histopathological results pointed CRINET. The patient also received Ommaya reservoir for intrathecal chemotherapy employment. The patient's preoperative and postoperative MRI scans and tumor's pathological features are described with a brief history of the disease in the literature. RESULTS: Lack of SMARCB1 gene immunoreactivity and presence of cribriform non-rhabdoid trabecular neuroepithelial cells led to the CRINET diagnosis. The surgical technique helped us to approach directly into the third ventricle and perform total resection and intraventricular lavage. The patient recovered without any perioperative complications and is consulted pediatric oncology for further treatment planning. CONCLUSION: With our limited knowledge on the matter, our presentation may provide an inside to the course and progress of the CRINET as a very rare tumor and may help to set a basis for future investigations focused on its clinical and pathological features. Long courses of follow-up periods are required for establishing treatment modules and assessing the responses to surgical resection techniques and chemotherapy protocols.

A Predictive Nomogram for Postoperative Hydrocephalus After Intra- and Paraventricular Tumor Resection: A Retrospective Study of 196 Patients.

BACKGROUND: Hydrocephalus is a common complication of intra- and paraventricular tumors both before and after tumor resection. We investigated the risk factors for postoperative hydrocephalus and established a predictive nomogram to improve surgical planning and adjust the frequency of postoperative clinical and radiographic monitoring. METHODS: A retrospective study of 196 intra- and paraventricular tumor patients with follow-up data was conducted to investigate the risk factors for postoperative hydrocephalus via univariate and multivariate Cox regression analyses. We developed a nomogram incorporating these factors based on multivariate analysis and according to scores calculated by the predictive model; a hazard function curve was used to compared risk of hydrocephalus. RESULTS: Among the 196 patients, 33 had postoperative hydrocephalus. Intraventricular tumor (P = 0.005), glioblastoma (P = 0.010), preoperative hydrocephalus (P = 0.007), and radiotherapy (P = 0.033) were independent risk factors for postoperative hydrocephalus. The nomogram including these independent risk factors had moderate predictive accuracy, with a concordance index of 0.716 (95% confidence interval [CI]: 0.605-0.828), while the area under the curve values at 6, 12, and 24 months were 0.708 (95% CI: 0.563-0.853), 0.763 (95% CI: 0.656-0.870) and 0.861 (95% CI: 0.779-0.943), respectively. The hazard function showed differences between the lower and higher nomogram score groups. The higher the nomogram score, the higher the risk of postoperative hydrocephalus (P < 0.001). CONCLUSIONS: The established nomogram performs well for predicting postoperative hydrocephalus. Clinicians can use this nomogram to review their practice regarding hydrocephalus associated with intra- and paraventricular tumors, plan surgical treatment and adjust the frequency of postoperative clinical and radiographic monitoring.

Immune Microenvironment and Lineage Tracing Help to Decipher Rosette-Forming Glioneuronal Tumors: A Multi-Omics Analysis.

Rosette-forming glioneuronal tumors (RGNT) are rare low-grade primary central nervous system (CNS) tumors. The methylation class (MC) RGNT (MC-RGNT) delineates RGNT from other neurocytic CNS tumors with similar histological features. We performed a comprehensive molecular analysis including whole-exome sequencing, RNAseq, and methylome on 9 tumors with similar histology, focusing on the immune microenvironment and cell of origin of RGNT. Three RGNT in this cohort were plotted within the MC-RGNT and characterized by FGFR1 mutation plus PIK3CA or NF1 mutations. RNAseq analysis, validated by immunohistochemistry, identified 2 transcriptomic groups with distinct immune microenvironments. The "cold" group was distinguishable by a low immune infiltration and included the 3 MC-RGNT and 1 MC-pilocytic astrocytoma; the "hot" group included other tumors with a rich immune infiltration. Gene set enrichment analysis showed that the "cold" group had upregulated NOTCH pathway and mainly oligodendrocyte precursor cell and neuronal phenotypes, while the "hot" group exhibited predominantly astrocytic and neural stem cell phenotypes. In silico deconvolution identified the cerebellar granule cell lineage as a putative cell of origin of RGNT. Our study identified distinct tumor biology and immune microenvironments as key features relevant to the pathogenesis and management of RGNT.

Minimally Invasive Resection of Intraventricular Pilocytic Astrocytoma Using the Aurora Surgiscope in an Adult Patient: Technical Note.

BACKGROUND: Pilocytic astrocytomas account for approximately 5%-6% of all gliomas and are most commonly diagnosed between the ages of 8 and 13 years. Although they may occur throughout the neuraxis, approximately two thirds arise from the cerebellum and optic pathway. Other locations of origin include midline structures such as thalamus, hypothalamus, and periventricular regions. Surgical approaches to lateral or third ventricular tumors include anterior transcallosal, subfrontal translamina terminalis, and anterior transcortical approaches. The Aurora Surgiscope is a single-use, disposable minimally invasive neurological endoscope designed for intraparenchymal hemorrhage evacuation. We present the successful use of this system to aid resection of a large intraventricular pilocytic astrocytoma. METHODS: A 29-year-old man presented with signs of developing hydrocephalus and was found to have a large intraventricular tumor, which was later identified to be a rare intraventricular pilocytic astrocytoma. A ventriculostomy was performed as a temporizing measure, and he was transferred to our tertiary care facility for surgical management. Sulcal dissection was performed, and the endoscope was inserted to create a minimally invasive corridor to the lateral ventricle. Using the endoscope, bimanual surgery using multiple instruments simultaneously was possible and enabled gross total resection of the tumor. RESULTS: The patient tolerated the procedure well and was discharged at his neurological baseline level. CONCLUSIONS: Extensive sulcal dissection preceding placement of the endoscope allowed access to the intraventricular space with minimal passage of parenchymal tissue. High-definition visualization was provided and allowed the operating surgeon to freely use both hands during surgery.

Rosette Forming Glioneural Tumor Treated with Conformal Radiation.

Rosette forming glioneural tumors (RGNT) are a rare type of low-grade brain tumor included in 2007 in WHO classification. Given the benign nature of the disease, a complete surgical excision has been considered optimum. However, a handful of cases have reported the locally aggressive nature of RGNT. In addition, radiation may also be considered for a tumor located in areas where surgical excision is difficult. We present a similar case, where surgical risk was weighed against resection and we treated the patient with conformal radiation.

Non-enhancing intraventricular tumours in adults.

Intraventricular tumours are relatively uncommon among all brain tumours, and non-enhancing lesions, mostly subependymoma, are even less frequently reported. Select cases of subependymoma can show variable contrast enhancement as well. Gross total surgical resection is recommended for treating these lesions, with no significant role of adjuvant chemotherapy or radiotherapy.

Large lateral intraventricular tumors - Outcome of radical surgery.

This is a retrospective analysis of 145 cases of lateral intraventricular tumors that were larger than 4 cm in their maximum dimension. The aim of surgery was radical tumor resection. During the period January 2000 to December 2019, 145 cases of lateral intraventricular tumors were treated by surgery by an interhemispheric approach. There were 101 males and 44 females. The ages of the patients ranged from 2 months to 77 years (average 29 years). Histological examination of tumors identified 73 central neurocytomas, 20 choroid plexus papillomas, 23 subependymal giant cell astrocytomas (SEGA), 5 ependymomas, 21 gliomas, 2 primitive neuroectodermal tumors (PNET/embryonal tumors) and 1 atypical teratoid rhabdoid tumor (ATRT). Nineteen patients had mild to severe hemiparesis in the immediate post-operative period. Eight patients died in the postoperative period. At a follow up of 1 year 137 patients were leading active and symptom free lives. Twenty seven patients received adjuvant radiation treatment. At a follow-up of more than 3 years, 8 additional patients died of their disease. Tumor recurrence or re-growth was observed in 13 patients and 2 patients needed reoperation. Surgery on large lateral intraventricular tumors can be associated with significant postoperative morbidity and mortality. Majority of tumors in this location are relatively 'low-grade' malignant tumors and when successfully treated, the long term outcome can be gratifying.