Tectal plate gliomas: a review

Experience of a reference center on ventriculo-gallbladder shunt as an alternative treatment for peritoneal failure in children

PURPOSE

Ventriculo-peritoneal shunt is the gold standard for non-obstructive hydrocephalus. Despite advances in material, infection prevention, and valve technologies, failure can still occur. The aim of this article is to present a comprehensive study based on the experience of a reference center in pediatric neurosurgery in Rio de Janeiro with the use of the ventriculo-gallbladder shunt as an alternative to peritoneal failure.

METHODS

A retrospective study was conducted from January 2018 to December 2023 of patients diagnosed with cerebrospinal fluid shunt dysfunction due to peritoneal failure and submitted to ventriculo-gallbladder shunt as an alternative in a reference center of Rio de Janeiro.

RESULTS

From 2018 to 2023, 18 peritoneal failures were diagnosed. Among them, 10 patients (55.5%) were selected for ventriculo-gallbladder shunt (VGS). Different causes were responsible for the hydrocephalus in these patients. VGS was placed at a mean age of 35.4 months. Four patients had temporary complications: 2 self-limited diarrheas in the first month and 2 shunt infections. After the resolution of the infection, a new VGS was placed successfully. The average follow-up was 18.8 months (follow-up 9-68 months) without further issues.

CONCLUSION

VGS is a viable option for patients facing peritoneal failure. This paper provides valuable insights into the surgical technique and outcomes associated with this alternative.

Occipital Interhemispheric Retrocallosal Transtentorial Approach to a Tectal Tumor in an 8-Year-Old Girl: Operative Video

Tectal plate tumors are a rare subset of midbrain tumors in pediatric populations. They are slow growing and low grade, with indolent and subtle manifestation unless they cause hydrocephalus.1-5 We present a tectal tumor in an 8-year-old girl (Video 1). Her clinical onset occurred with headache, vomiting, and seizure secondary to intracranial hypertension. MRI revealed a ring-enhanced, roundish lesion of tectal plate, with posterior displacement of quadrigeminal corpora determining aqueductal stenosis and obstructive triventricular hydrocephalus. First, to restore CSF circulation, we performed an endoscopic third-ventriculostomy without lesion's biopsy, since there was normal brain tissue within the third ventricle and the tumor. Tumoral marker values were in the average range, so surgery was planned to remove the tumor. The patient, after the positioning of external lumbar drainage, underwent an occipital posterior interhemispheric retrocallosal transtentorial approach, which represents a direct surgical corridor to quadrigeminal cistern and quadrigeminal plate. Arachnoidal dissection of mesencephalic cistern and cutting of the tentorium are mandatory to obtain adequate exposure of quadrigeminal region, control over vascular structures, and lesser brain retraction. Identification of anatomical components and relationships between quadrigeminal plate with vein of Galen, PCA branches, tentorium, and medial occipital veins represents a crucial point. When this approach is selected, the venous anatomy must be navigated with caution. Angiography's venous phase may provide additional planning information.6 Coagulation of vascular structures such as occipital veins is carefully avoided since it creates risk of venous infarction, leading to visual loss. Histologic examination revealed a rosette-forming glioneuronal tumor (grade I WHO 20217).

Unveiling the Efficacy of Gamma Knife Radiosurgery for Tectal Plate Gliomas

BACKGROUND AND OBJECTIVES

Tectal plate gliomas (TPGs) are midbrain tumors that grow slowly and have a benign clinical course. Most TPGs are low-grade astrocytomas, but they can encompass various histological tumor types. Gamma Knife radiosurgery (GKRS) is being explored as a potentially safe and effective treatment option for TPGs, although research in this area is limited. This study aims to evaluate GKRS's efficacy and safety in patients with TPG and provide a comprehensive review of existing literature on the topic.

METHODS

This retrospective, single-center study included 48 patients with consecutive TPG who underwent GKRS between September 2005 and June 2022. Patients diagnosed with TPGs based on radiological or tissue-based criteria and who had a minimum follow-up period of 12 months were eligible for inclusion. The primary end points were local control and the absence of GKRS-associated or tumor-associated mortality and morbidity.

RESULTS

During a median follow-up of 28.5 months (range, 12-128), the radiological assessment showed tumor control in all cases, with 16.7% achieving a complete response and 68.8% achieving a partial response. Pseudoprogression occurred in 6.2% of cases, with onset ranging from 3 to 8 months. Clinical outcomes revealed no permanent neurological deterioration, with symptoms improving in 14.6% of patients and remaining stable in the others. One patient in the pseudoprogression group experienced transient Parinaud syndrome. One patient died during follow-up because of unrelated causes. The mean survival time after GKRS was 123.7 months. None of the clinical, radiological, or radiosurgical variables showed a correlation with partial/complete response, clinical improvement, or overall survival.

CONCLUSION

There is limited research available on the management of TPGs, and this study presents the largest patient cohort treated with GKRS, along with a substantial follow-up duration. Despite its limitations, this study demonstrates the efficacy and low-risk profile of GKRS for TPGs.

Modern Radiation Treatment Planning Parameters and Outcomes in Pediatric Tectal Gliomas

Purpose

Pediatric low-grade tectal gliomas are rare, indolent tumors of the brain stem. We reviewed outcomes of pediatric patients who received a diagnosis of low-grade tectal gliomas and report dosimetric parameters for those receiving radiation therapy (RT).

Methods and Materials

We retrospectively reviewed all pediatric patients (age <18 years) at our institution diagnosed with a low-grade glioma between 1993 and 2020 (n = 288). Twenty-three patients with tectal gliomas were identified. Patients who received RT (n = 8) had detailed dosimetric analyses performed. Doses to critical structures and any resulting toxicities were reviewed. Minimum follow-up was 2 years and complete follow-up was available for all patients.

Results

Twenty-three patients, with a median age of 8.9 years, were included (range, 0.5-16.2 years). At a median follow-up of 7.4 years (range, 2-24 years), all were alive at the end of the study period. Three patients (13%) were treated with upfront RT; none of these patients developed local failure (LF) after a median follow-up of 10.6 years. One patient was treated with upfront chemotherapy with no evidence of progression afterward. Nineteen patients were initially observed after diagnosis and 26% of them (n = 5) experienced local progression. All 5 were treated with salvage RT, with 1 patient requiring further treatment with chemotherapy. Fractionation schedules for patients undergoing upfront or salvage RT included 50.4 Gy in 28 fractions (n = 4), 54 Gy in 30 fractions (n = 2), and 51 Gy in 30 fractions (n = 2). For patients treated after 2007, the gross tumor volume was delineated on a T2 magnetic resonance imaging with an average gross tumor volume-to-planning target volume expansion of 4.5 mm (range, 3-5 mm). Detailed dosimetric parameters were available for all patients treated with RT.

Conclusions

Our review supports the indolent behavior for most tectal gliomas. For the subset of tumors with evidence of progression, modern photon RT results in excellent oncologic outcomes with minimal late effects.

Tectal Plate Glioma: A Clinical and Radiologic Analysis of Progression and Management in Adults

BACKGROUND

Tectal plate gliomas (TPGs) are a heterogeneous group of uncommon brain tumors. TPGs are considered indolent and are usually managed conservatively but they have the potential to transform into higher-grade tumors. The aims of this study were to investigate the natural history of adult TPG, treatment outcomes, and overall survival.

METHODS

A retrospective cohort analysis was performed of adult patients with TPG between 1993 and 2021. Baseline clinical, radiologic, and management characteristics were collected. The primary outcome was tumor progression, defined as increasing size on radiologic assessment or new gadolinium contrast enhancement. Secondary outcomes included management and mortality.

RESULTS

Thirty-nine patients were included, of whom 23 (52.2%) were men. Median age at diagnosis was 35 years (interquartile range, 27-53). Radiologic tumor progression was observed in 8 patients (20.5%). The 10-year progression-free survival was 72.6% (95% confidence interval [CI], 0.58-0.91). The 10-year overall survival was 86.5% (95% confidence interval, 0.75-1.0). Cerebrospinal fluid diversion procedures were used in 62% of the cohort (n = 24). Seventeen patients (43.6%) underwent at least 1 endoscopic third ventriculostomy, whereas only 6 patients (15.4%) underwent at least 1 ventriculoperitoneal shunt.

CONCLUSIONS

TPG has an overall favorable clinical prognosis, although progression occurs in 1 in 5 patients. Showing accurate factors by which patients with TPG may be risk stratified should be a key area of further research. A follow-up duration of 10 years would be a reasonable window based on the radiologic progression rates in this study; however, larger cohort studies are needed to answer both questions definitively.

Atypical Molecular Features of Pediatric Tectal Glioma: A Single Institutional Series

We present 4 children (diagnosed between 1 and 8 y, 3 females and 1 male) with molecularly distinct tectal gliomas (2 KRAS mutant, 1 EGFR mutant, 1 SRGAP3-RAF-1 fusion) that contributes to the growing literature of this uncommonly biopsied tumor. The patient with EGFR R222C mutation had a more severe course, earlier diagnosis, subsequent leptomeningeal metastatic disease, required more aggressive therapies, and died 9 years after diagnosis. Patients with KRAS mutations and SRGAP3-RAF-1 fusion had a more indolent course. Our series expands the molecular phenotype of tectal glioma with the potential for leptomeningeal dissemination. Future studies on establishing genotypic/phenotypic correlation from those who undergo biopsy are needed.

Pediatric Pineal Region Tumors: Special Reference to Posterior Interhemispheric Trans-Tentorial Approach

Pediatric pineal region tumors consist of tumors of pineal gland origin and parapineal origin. The former are comprised of germ cell tumor (GCT) and pineal parenchymal tumor. The latter originate from the surrounding neural structures, such as the midbrain and thalamus; thus, they are often benign gliomas during childhood. Pineal region tumors often cause obstructive hydrocephalus, which is the main cause of presenting symptoms. Advanced imaging discloses precise location and extension of the tumor and associated anomalies such as hydrocephalous, dissemination, hemorrhage, etc. Hydrocephalus has been managed with CSF diversion, mostly using an endoscopic third ventriculostomy. Because of different treatment paradigms for each tumor type, histological confirmation is needed either through biopsy, tumor markers for GCTs, and/or surgical resection sampling. Radical resection of these tumors remains a challenge due to their deep-seated location and involvement of delicate neural and vascular structures. Comparison of common craniotomy approaches, occipital transtentorial (OT) and infratentorial supracerebellar (ITSC), is reviewed for their advantages and disadvantages. Surgical area exposure and blind spots are important factors for successful tumor removal. The surgical techniques and nuances that the author employs for tumor resection via a posterior interhemispheric transtentorial approach are presented.

Retrospective Analysis of Imaging Characteristics of Tectal Gliomas

BACKGROUND AND PURPOSE

Tectal gliomas (TGs) are rare tumors that involve critical locations in the brainstem, including the superior and inferior colliculi and the Sylvian aqueduct. The rarity of these tumors and the lack of large clinical studies have hindered adequate understanding of this disease. We sought to determine the association between imaging characteristics of TG and progression-free survival (PFS).

MATERIALS AND METHODS

In this retrospective cohort study, impact of imaging characteristics (contrast enhancement, calcifications, cystic changes, presence of hydrocephalus) on survival was analyzed for 39 patients with TG. We used the Kaplan-Meier survival analysis method for determining the association between imaging characteristics and PFS. Progression-free survival was measured from time of diagnosis to radiographic or pathological disease progression during observation period. Progression was defined as more than 25% increase of the lesion in size, per response assessment in neuro-oncology, together with clinical deterioration and/or a need for intervention. Progression-free survival differences by various imaging characteristics were assessed using the log-rank test and univariable Cox proportional hazard regression. Because most of the studies in the current literature tend to overrepresent pediatric patients, we aimed to determine the association between TG tumors' imaging characteristics and PFS in both adult and pediatric patients. All statistical analyses were performed using STATA version 16.1 (Stata Corp, College Station, Tex).

RESULTS

Of the 39 patients, radiographic tumor progression was observed in 15 cases (38.5%). Median PFS for 39 patients during observation was 21.8 years. Tectal gliomas that showed contrast enhancement initially or developed contrast enhancement during surveillance on magnetic resonance imaging had significantly lower PFS than those without (hazard ratio, 3.55; 95% confidence interval, 1.09-11.58; log-rank P value, 0.02).

CONCLUSIONS

Analysis of this patient population showed that contrast-enhancing TGs should not be categorically defined as benign lesions. This subgroup of patients should be followed closely for signs of progression.

MRI-based diagnosis and treatment of pediatric brain tumors: is tissue sample always needed?

Traditional management of newly diagnosed pediatric brain tumors (PBTs) consists of cranial imaging, typically magnetic resonance imaging (MRI), and is frequently followed by tissue diagnosis, through either surgical biopsy or tumor resection. Therapy regimes are typically dependent on histological diagnosis. To date, many treatment regimens are based on molecular biology. The scope of this article is to discuss the role of diagnosis and further treatment of PBTs based solely on MRI features, in light of the latest treatment protocols. Typical MRI findings and indications for surgical biopsy of these lesions are described.

Long-Term Outcomes of Patients with Hydrocephalus Secondary to Tectal Plate Glioma versus Idiopathic Aqueductal Stenosis: Results from a Single Center

INTRODUCTION

Tectal plate gliomas (TPG) constitute a distinct entity of benign tumors of the brain stem which show an indolent clinical course. Adequate treatment of secondary hydrocephalus is undoubtedly a major factor in the outcome. However, little is known about to what degree the tumor itself determines the long-term outcome of these patients.

METHODS

We retrospectively analyzed and compared the clinical and radiological data of 16 pediatric TPG patients with data of 12 pediatric idiopathic aqueductal stenosis (IAS) patients treated in our center from 1988 to 2018. For both groups, we assessed the long-term outcome in terms of hydrocephalus management, and for the TPG group, we assessed tumor growth during follow-up. In a separate prospective part of the study, we performed a neuropsychological evaluation in a subgroup of patients using a standardized testing battery, covering intelligence, learning, memory, executive functions, and an inventory on depression.

RESULTS

In the TPG group, the mean clinical and radiological follow-up was 84 and 70 months, respectively. On average, the maximum diameter of the tumor increased by 11% (p = 0.031) and the estimated tumor volume with 35% (p = 0.026) on radiological follow-up. The fronto-occipital horn ratio (FOHR) decreased by 23% on average after treatment. In the IAS group, the mean clinical and radiological follow-up was 117 and 85 months, respectively. In this group, the FOHR decreased by 21% on average. Neurocognitive testing revealed significant higher scores in the TPG group on global intelligence (TPG = 109, IAS = 85.5, U = 3, p < 0.01, z = -2.71), performance (TPG= 100, IAS = 85, U = 7, p = 0.03, z = -2.2), and verbal intelligence (TPG = 122, IAS = 91.5, U = 2, p < 0.00, z = -2.87) as well as working memory (TPG = 109.5, IAS = 77, U = 0.5, p = 0.01, z = -2.46).

CONCLUSION

Our results suggest that the long-term outcome in TPG patients is acceptable and that cognition is substantially better preserved than in patients with IAS. This puts the idea of a significant contribution of the tumoral mass to disease outcome on the long term in question. Adequate and prompt management of hydrocephalus is the most important factor in long-term cognitive outcome.

Tectal Low-Grade Glioma with H3 K27M Mutation

BACKGROUND

In the revised World Health Organization 2016 classification of central nervous system tumors, "diffuse midline glioma, H3 K27M-mutant" has been added as a new diagnostic entity. However, some confusion exists concerning this diagnostic entity because H3 K27M-mutant diffuse midline glioma is diagnosed with grade IV regardless of morphologic phenotype. Furthermore, the significance of H3 K27M mutation in tumors that aren't typical "diffuse midline glioma, H3 K27M-mutant," such as those with an unusual location and nontypical histology, remains unclear.

CASE DESCRIPTION

To elucidate further such unusual tumors, we describe here a rare case of pediatric low-grade glioma located in the tectum, which was morphologically a pilocytic astrocytoma (PA) with genetically H3 K27M mutation but no microvascular proliferation, necrosis, mitoses, or other genetic alterations, insofar as we were able to observe. At the latest follow-up, 28 months after surgery, radiotherapy, and chemotherapy, the patient was found to be free from any neurologic deficits and MRI demonstrated that the tumor was stable without tumor regrowth. This case might be identified as "diffuse midline glioma, H3 K27M-mutant", grade IV, when applying only the current World Health Organization 2016 classification. In addition, we discuss the morphologically benign gliomas harboring the H3 K27M mutation based on the literature.

CONCLUSIONS

We describe here a rare case and present a short literature review of circumscribed/nondiffuse gliomas, particularly in PA with H3 K27M mutation. However, the significance of H3 K27M mutation for PA remains unclear, so further studies and clinical data are needed to elucidate the biology and optimal treatment of such tumors.

Rare clinical presentations of pleomorphic xanthoastrocytoma with a high proliferative index: Two case reports

INTRODUCTION

Pleomorphic xanthoastrocytomas (PXA) are rare, typically benign, slow-growing tumors that commonly occur in the cerebral hemispheres. We describe two cases of clinically aggressive PXA with uncommon locations; one was in the tectal plate, and the other had simultaneous multicentric lesions.

PATIENT CONCERNS

The both cases presented with severe headache with no significant past medical history.

DIAGNOSIS

PXA World Health Organization grade II were histopathologically diagnosed from surgically resected specimens, and immunohistochemical and sequence analysis revealed a high Ki-67 proliferative index and BRAF V600E mutation in both the cases.

INTERVENTIONS

The first case presented with multicentric lesions and underwent partial resection, whereas the second case presented with a tectal plate tumor that was managed by gross total surgical resection. Strong 5-aminolevulinic acid (5-ALA)-induced fluorescence was observed in both the lesions. Postoperative radiotherapy plus concomitant and adjuvant temozolomide was administered to both the patients.

OUTCOMES

Despite completing adjuvant chemo-radiotherapy, both the patients had local tumor recurrence at 2 and 5 months after the operation, respectively.

CONCLUSION

The progressive clinical courses in our cases suggest that additional postoperative therapy should be considered during the treatment of PXA with a high Ki67 index, and that temozolomide with radiotherapy, followed by temozolomide maintenance therapy, may not prevent recurrence in such tumors. Importantly, our experience implies that unlike other subtypes of low grade gliomas, 5-ALA fluorescence is useful for intraoperative visualization of PXA.

Tectal gliomas: assessment of malignant progression, clinical management, and quality of life in a supposedly benign neoplasm

OBJECTIVE Tectal gliomas constitute a rare and inhomogeneous group of lesions with an uncertain clinical course. Because these supposedly benign tumors are frequently followed up by observation over many years, the authors undertook this analysis of their own case series in an effort to demonstrate that the clinical course is highly variable and that there is a potential for a progressive biology. METHODS Clinical data analysis of 23 cases of tectal glioma (involving 9 children and 14 adults) was performed retrospectively. Radiographic data were analyzed longitudinally and MR images were evaluated for tumor volume, contrast enhancement, and growth progression. Quality of life was assessed using the EORTC BN20 and C30 questionnaires during follow-up in a subgroup of patients. RESULTS The patients' mean age at diagnosis was 29.2 years. The main presenting symptom at diagnosis was hydrocephalus (80%). Six patients were treated by primary tumor resection (26.1%), 3 patients underwent biopsy followed by resection (13.1%), and 3 patients underwent biopsy only (13.1%). For additional treatment of hydrocephalus, 14 patients (60.9%) received shunts and/or endoscopic third ventriculostomy. Radiographic tumor progression was observed in 47.9% of the 23 cases. The mean time between diagnosis and growth progression was 51.5 months, and the mean time to contrast enhancement was 69.7 months. Histopathological analysis was obtained in 12 cases (52.2%), resulting in 5 cases of high-grade glioma (3 cases of glioblastoma multiforme [GBM], grade IV, and 2 of anaplastic astrocytoma, grade III), 5 cases of pilocytic astrocytoma, 1 diffuse astrocytoma, and 1 ganglioglioma. Malignant progression was observed in 2 cases, with 1 case progressing from a diffuse astrocytoma (grade II) to a GBM (grade IV) within a period of 13 years. Quality-of-life measurements demonstrated distinct functional deficits compared to a healthy sample as well as glioma control cohorts. CONCLUSIONS Analysis of this case series shows that a major subpopulation of tectal gliomas show progression and malignant transformation in children as well as in adolescents. These tumors therefore cannot be considered inert lesions and require histological confirmation and close follow-up. Quality-of-life questionnaires show that tectal glioma patients might benefit from special psychological support in emotional, social, and cognitive functionality.

Brain Tectal Tumors: A Flexible Approach

BACKGROUND AND IMPORTANCE

Mesencephalic tectal gliomas represent a subset of midbrain tumors, which are more frequent in children than in adults. They usually become symptomatic when causing hydrocephalus by occluding the aqueduct. Because of their slow progression, due to their benign histology, they are characterized by a relatively good prognosis, although hydrocephalus might jeopardize patients' prognosis. Treatment is usually represented by cerebrospinal fluid diversion associated or not with biopsy.

CLINICAL PRESENTATION

We report 2 illustrative cases of tectal gliomas in adults where endoscopic third ventriculostomy (ETV) and simultaneous endoscopic biopsy were obtained during the same operation by means of a single burr hole with a flexible endoscope.

CONCLUSION

We recommend using this overlooked neurosurgical tool for such cases, since it allows the surgeon to safely perform an ETV, then judge whether biopsy can be done or not, without harming the patient, and possibly achieving an important piece of information (histopathological diagnosis) to manage this subset of oncological patients.

Endoscopic third ventriculostomy for hydrocephalus due to tectal glioma

BACKGROUND

Tectal gliomas commonly present with hydrocephalus from obstruction of the aqueduct of Sylvius. The creation of a ventriculostomy in the floor of the third ventricle (ETV) has been previously reported to by-pass aqueduct obstruction. The goal of this study was to determine the safety and efficacy of ETV in the presence of an obstructing tectal glioma.

METHODS

We retrospectively reviewed the clinical presentation, management, and clinical outcome after ETV in patients diagnosed with tectal glioma and obstructive hydrocephalus in our institution over a period of 15 years. Shunt freedom at follow-up was the main outcome variable. Long-term clinical outcome was assessed at the most recent clinic visit. Clinical outcome was ranked as excellent, good, or poor according to resolution of symptoms and patient functional status.

RESULTS

The median age at presentation was 16.5 years (range: 6.4 to 59 years) and the most common presenting symptom was headache. Eleven patients had ETV as a primary procedure and three patients underwent ETV as a substitute for shunt revision at the time of shunt failure. At follow-up (median 3.9 years, range: 2.2 to 7 years) 13 of 14 patients remain shunt independent with excellent (n=9) or good outcomes (n=5).

CONCLUSIONS

In patients with tectal glioma causing obstructive hydrocephalus, ETV can be performed safely in the primary setting or as a substitute for shunt revision. A high rate of shunt freedom (78%-100%) at prolonged follow-up can be expected in this patient population.

Tectal Lesions in Children: A Long-Term Follow-Up Volumetric Tumor Growth Analysis in Surgical and Nonsurgical Cases

BACKGROUND/AIMS

Different tectal masses have been described; most are low-grade gliomas. Only 20-30% of all lesions grow, as shown on follow-up MRIs, requiring surgical resection at some point. The aim of this study is to describe the experience of a single institution managing pediatric patients with tectal lesions.

METHODS

We retrospectively studied and analyzed 40 children with tectal lesions managed from 1990 to 2006; the mean age at diagnosis was 9.4 years. A volumetric classification was used to analyze tumor growth trends. More than 1 year of imaging follow-up was available for 23 patients.

RESULTS AND CONCLUSION

Medium- and large-volume-size lesions were associated with the need for surgery. About half of the nonsurgical lesions grew at least 50% over a period of 4.5 years and did not require surgical resection.

Pilocytic astrocytomas

Pilocytic astrocytoma (PA) is the most common pediatric brain tumor in children. PAs are a distinct histologic and biologic subset of glioma that have a slow growth rate and may even spontaneously regress. These tumors tend to arise in the cerebellum and chiasmatic/hypothalamic region, but can also occur in other regions of the central nervous system. Dissemination is uncommon, but may occur in newly diagnosed PAs. Alterations in the Ras/RAF/mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway (Ras/ERK) have been discovered in a majority of PAs, with KIAA1549-BRAF fusions being the most commonly identified alteration. Children with neurofibromatosis 1 are predisposed to developing PAs, primarily within the optic pathway. When required, treatment consists of surgery, chemotherapy, and/or radiation, although new molecular agents targeting the Ras/ERK and related signaling pathways are promising new approaches. The 10-year survival rates are greater than 90% in pediatric patients; however, they are poorer in adults. Tumors that are amenable to complete resection (i.e., cerebellum and cortex) have the best overall survival.