Tectal gliomas: natural history of an indolent lesion in pediatric patients

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.

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.

Management strategies for pediatric patients with tectal gliomas: a systematic review

Pediatric tectal gliomas generally have a benign clinical course with the majority of these observed radiologically. However, patients often need treatment for obstructive hydrocephalus and occasionally require cytotoxic therapy. Given the lack of level I data, there is a need to further characterize management strategies for these rare tumors. We have therefore performed the first systematic review comparing various management strategies. The literature was systematically searched from January 1, 2000, to July 30, 2020, to identify studies reporting treatment strategies for pediatric tectal gliomas. The systematic review included 355 patients from 14 studies. Abnormal ocular findings-including gaze palsies, papilledema, diplopia, and visual field changes-were a common presentation with between 13.6 and 88.9% of patients experiencing such findings. CSF diversion was the most performed procedure, occurring in 317 patients (89.3%). In individual studies, use of CSF diversion ranged from 73.1 to 100.0%. For management options, 232 patients were radiologically monitored (65.4%), 69 received resection (19.4%), 30 received radiotherapy (8.4%), and 19 received chemotherapy (5.4%). When examining frequencies within individual studies, chemotherapy ranged from 2.5 to 29.6% and radiotherapy ranged from 2.5 to 28.6%. Resection was the most variable treatment option between individual studies, ranging from 2.3 to 100.0%. Most tectal gliomas in the pediatric population can be observed through radiographic surveillance and CSF diversion. Other forms of management (i.e., chemotherapy and radiotherapy) are warranted for more aggressive tumors demonstrating radiological progression. Surgical resection should be reserved for large tumors and/or those that are refractory to other treatment modalities.

Pineal region tumors: an entity with crucial anatomical nuances

PURPOSE

Intra-axial "pineal region" tumors include pineal, tectal, and aqueductal tumors. All three tumor subgroups cause obstruction of the aqueduct; however, they differ in radiological nuances, pathology, differential diagnosis, and treatment. The goal of this manuscript is to describe the radiological, clinical, and pathological nuances that differentiate between these subgroups.

METHODS

All patients with intra-axial pineal region tumors were analyzed retrospectively, including demographics, radiological characteristics, pathology, treatment, and outcome.

RESULTS

Forty-nine patients (1-69 years of age) were included: 19 pineal, 10 tectal, 10 aqueductal, 4 periaqueductal, and 6 complex. The 3 main subgroups differed in various radiological and anatomical nuances. Age and gender did not differ between groups. Other factors that did not differ between groups included T1 and T2 signals, presence of blood products, a normally located (non-displaced) tectum, anterior tectal displacement, thalamic involvement, and presence of hydrocephalus. The pathological spectrum differed between the 3 main subgroups, as well as the surgical treatment, and outcome.

CONCLUSIONS

Despite sharing a close anatomical location, as well as all causing obstruction of the aqueduct with secondary hydrocephalus, the differential diagnosis, diagnostic methods, and possible treatment and surgical options differ between the various subgroups. Anatomical nuances are described to better delineate the various tumor subgroups and recommend specific treatment approaches.

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.

Case Reports of Tectal Plate Gliomas Showing Indolent Course

From 2004 to 2020, we studied three pediatric patients (age: 9-13 years, all male) and one adult patient (age: 29 years, female) with tectal plate glioma with obstructing hydrocephalus on MRI. One patient had neurofibromatosis type 1. All patients complained about headaches and vomiting, and one patient had diplopia. Endoscopic third ventriculostomy (ETV) was underwent in all patients and a biopsy was obtained from two patients. Pathologic diagnoses were a pilocytic astrocytoma and a low-grade glioma. After ETV with or without biopsy, neurological symptoms were improved in all patients. Three patients did the clinical and radiological follow-up without adjuvant treatment. One patient underwent gamma knife radiosurgery. In two pediatric patients and the adult patient, there was no clinical and radiological progression after 6.2, 6.9, and 8.0 years, respectively. One pediatric patient whose lesion had focal enhancement had radiologic progression without any neurologic symptoms after 5.1 years. Without adjuvant treatment for this lesion, there was no clinical deterioration neither further radiological progression for 6.2 years after radiological aggravation. Tectal plate gliomas showed indolent clinical courses, even after radiologic tumor progression. After the treatment of obstructing hydrocephalus, clinical and radiologic follow-up can be recommended for indolent tectal plate gliomas.

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.

Rescue bevacizumab following symptomatic pseudoprogression of a tectal glioma post-radiotherapy: a case report and review of the literature

PURPOSE

Radiation-induced pseudoprogression is a subacute clinical entity that is distinct from radiation necrosis and mimics tumor progression. Bevacizumab is a well-described treatment option for radiation necrosis, but its role in pseudoprogression is not clearly defined.

METHODS

We report a case of radiation-induced pseudoprogression rescued with bevacizumab in a 20-year-old man with a biopsy-proven low-grade astrocytoma of the tectum. A review of the literature was also conducted specific to bevacizumab as a treatment for symptomatic pseudoprogression after radiotherapy for CNS tumors.

RESULTS

This patient was treated with definitive intensity modulated stereotactic radiotherapy at a total dose of 54 Gy delivered in 30 daily fractions. Six weeks after radiotherapy the patient developed progressive headache, weakness and a documented deterioration in vision, which was accompanied by worsening of radiographic findings. A diagnosis of pseudoprogression was made and after limited benefit from a trial of dexamethasone, four cycles of bevacizumab were administered which resulted in rapid clinical and radiographic improvement.

CONCLUSIONS

Our findings support the potential use of bevacizumab as a rescue agent for symptomatic pseudoprogression.

Tectal glioma as a distinct diagnostic entity: a comprehensive clinical, imaging, histologic and molecular analysis

Tectal glioma (TG) is a rare low-grade tumor occurring predominantly in the pediatric population. There has been no detailed analysis of molecular alterations in TG. Risk factors associated with inferior outcome and long-term sequelae of TG have not been well-documented. We retrospectively studied TGs treated or referred for review at St. Jude Children’s Research Hospital (SJCRH) between 1986 and 2013. Longitudinal clinical data were summarized, imaging and pathology specimen centrally reviewed, and tumor material analyzed with targeted molecular testing and genome-wide DNA methylation profiling. Forty-five patients with TG were included. Twenty-six (57.8%) were male. Median age at diagnosis was 9.9 years (range, 0.01–20.5). Median follow-up was 7.6 years (range, 0.5–17.0). The most common presenting symptoms were related to increased intracranial pressure. Of the 22 patients treated at SJCRH, 19 (86%) required cerebrospinal fluid diversion and seven (32%) underwent tumor-directed surgery. Five patients (23%) received radiation therapy and four (18%) systemic therapy. Ten-year overall and progression-free survival were 83.9 ± 10.4% and 48.7 ± 14.2%, respectively. Long-term morbidities included chronic headaches, visual symptoms and neurocognitive impairment. Lesion ≥3cm², contrast enhancement and cystic changes at presentation were risk factors for progression. Among those with tumor tissue available, 83% showed growth patterns similar to pilocytic astrocytoma and 17% aligned best with diffuse astrocytoma. BRAF duplication (a marker of KIAA1549-BRAF fusion) and BRAF V600E mutation were detected in 25% and 7.7%, respectively. No case had histone H3 K27M mutation. DNA methylation profile of TG was distinct from other brain tumors. In summary, TG is an indolent, chronic disease with unique clinical and molecular profiles and associated with long term morbidities. Large size, contrast enhancement and cystic changes are risk factors for progression.

Diagnosis and treatment for pure aqueductal tumor

Pure aqueductal tumor (PAT) typically originates from pure aqueductal region and is extremely rare. It is radiographically similar to tectal glioma. We examined two patients with PATs who were diagnosed with pilocytic astrocytoma and rosette-forming glioneuronal tumor. Both cases showed a progressive clinical course. It is important to distinguish between PAT and tectal glioma by radiographic imaging because the treatment strategy is different. While observation is common for tectal gliomas, a biopsy is recommended at the same time of endoscopic third ventriculostomy for PAT with hydrocephalus. Low-grade PATs show an aggressive clinical course in some cases. Our two cases also showed aggressive course in spite of no genetic aggressive mutations. Sagittal view by constructive interference in steady state (CISS) imaging was helpful to make an accurate diagnosis of PAT. Close observation is needed if PAT is diagnosed as low-grade tumor.

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.

Clinical profile and outcomes in brainstem glioma: An institutional experience

Aim of the Study:

This study was to analyze the clinical outcomes of brain stem glioma treated with radiation therapy (RT) in our institution.

Material and Methods:

Records of 48 patients with brainstem glioma treated between January 2007 and January 2013 were reviewed. Demographic variables, clinical variables, radiological findings and treatment details with respect to age, sex, location of tumor ( pontine Vs non pontine ), signs and symptoms, RT dose, follow up period and outcomes were recorded. Patients were subdivided into two groups based on their age, age <15 years (Group I) and age >=15 yrs (Group II).

Results:

The median age at diagnosis was 10 years (range 4-50). Male to female ratio was 11:10. Of the 48 cases analyzed, 27 patients (56%) were in group I and 21 (44%) were in group II. Radiologically, 90.5% had involvement of pons. 10 (21%) patients received RT dose >60 Gy and 38 (79 %) patients received RT dose of 54-60 Gy. Median overall survival was 7months (range 3-44 months). Median overall survival in Group I and Group II was 4 months and 10 months respectively (P = 0.042).

Conclusions:

Brain stem glioma in pediatric age group is associated with worse outcomes than in adults.

Pediatric brainstem gliomas: new understanding leads to potential new treatments for two very different tumors

Pediatric brainstem gliomas include low-grade focal brainstem gliomas (FBSG) and high-grade diffuse intrinsic pontine gliomas (DIPG). These tumors share a crucial and eloquent area of the brain as their location, which carries common challenges for treatment. Otherwise, though, these two diseases are very different in terms of presentation, biology, treatment, and prognosis. FBSG usually present with greater than 3 months of symptoms, while DIPG are usually diagnosed within 3 months of symptom onset. Surgery remains the preferred initial treatment for FBSG, with chemotherapy used for persistent, recurrent, or inoperable disease; conversely, radiation is the only known effective treatment for DIPG. Recent developments in biological understanding of both tumors have led to new treatment possibilities. In FBSG, two genetic changes related to BRAF characterize the majority of tumors, and key differences in their biological effects are informing strategies for targeted chemotherapy use. In DIPG, widespread histone H3 and ACVR1 mutations have led to new hope for effective targeted treatments. FBSG has an excellent prognosis, while the long-term survival rate of DIPG tragically remains near zero. In this review, we cover the epidemiology, biology, presentation, imaging characteristics, multimodality treatment, and prognosis of FBSG and DIPG, with a focus on recent biological discoveries.

Focal brainstem gliomas. Advances in intra-operative management

Improved neuronavigation guidance as well as intraoperative imaging and neurophysiologic monitoring technologies have enhanced the ability of neurosurgeons to resect focal brainstem gliomas. In contrast, diffuse brainstem gliomas are considered to be inoperable lesions. This article is a continuation of an article that discussed brainstem glioma diagnostics, imaging, and classification. Here, we address open surgical treatment of and approaches to focal, dorsally exophytic, and cervicomedullary brainstem gliomas. Intraoperative neuronavigation, intraoperative neurophysiologic monitoring, as well as intraoperative imaging are discussed as adjunctive measures to help render these procedures safer, more acute, and closer to achieving surgical goals.

Gamma Knife radiosurgery for low-grade tectal gliomas

BACKGROUND

Tectal gliomas are present in a critical location that makes their surgical treatment difficult. Stereotactic radiosurgery presents an attractive noninvasive treatment option. However, tectal gliomas are also commonly associated with aqueductal obstruction and consequently hydrocephalus. This necessitates some form of CSF diversion procedure before radiosurgery. The aim of the study was to assess the efficacy and safety of Gamma Knife radiosurgery for tectal gliomas.

PATIENTS AND METHODS

Between October 2002 and May 2011, 11 patients with tectal gliomas were treated with Gamma Knife radiosurgery. Five patients had pilocytic astrocytomas and six nonpilocytic astrocytomas. Ten patients presented with hydrocephalus and underwent a CSF diversion procedure [7 V-P shunt and 3 endoscopic third ventriculostomy (ETV)]. The tumor volume ranged between 1.2-14.7 cc (median 4.5 cc). The prescription dose was 11-14 Gy (median 12 Gy).

RESULTS

Patients were followed for a median of 40 months (13-114 months). Tumor control after radiosurgery was seen in all cases. In 6/11 cases, the tumors eventually disappeared after treatment. Peritumoral edema developed in 5/11 cases at an onset of 3-6 months after treatment. Transient tumor swelling was observed in four cases. Four patients developed cysts after treatment. One of these cases required aspiration and eventually disappeared, one became smaller spontaneously, and two remained stable.

CONCLUSION

Gamma Knife radiosurgery is an effective and safe technique for treatment of tectal gliomas. Tumor shrinkage or disappearance after Gamma Knife radiosurgery may preclude the need for a shunt later on.

True aqueductal tumors: a unique entity

BACKGROUND

Pure aqueductal tumors (ATs) differ from pineal region and tectal/tegmental tumors in that they are epicentered within the aqueduct. Nevertheless, these tumors are rarely described as a separate type of tumor, and are often grouped with other lesions located in the same vicinity. The present multicenter study focuses on our experience treating patients with pure ATs.

METHODS

Data from three large tertiary centers was collected retrospectively, including presenting symptoms, treatment paradigm, surgical approaches, pathology, and outcome.

RESULTS

Between 1999 and 2013, 16 patients with AT were diagnosed and treated at the three tertiary centers. Ages at presentation ranged from 5.5 to 57 years. Thirteen patients presented with hydrocephalus-related symptoms, and two were identified incidentally. Thirteen patients underwent an endoscopic third ventriculostomy, and two of these underwent a simultaneous endoscopic biopsy (one grade II ependymoma, one non-specified low-grade glioma). Two others underwent shunt placement. Three patients underwent resection due to tumor progression. Pathologies included glioblastoma multiforme, glioneural tumor, and ependymoma grade II. All non-resected tumors remained stable or grew only minimally.

CONCLUSIONS

ATs are a rare entities that usually present with obstructive hydrocephalus. Treatment includes primarily cerebrospinal fluid drainage (preferably via an endoscopic third ventriculostomy). Simultaneous endoscopic biopsy may be done in selected cases. Tumor resection should be reserved for growing tumors; the trans-fourth ventricular or trans-choroidal approaches are probably safer than other approaches used to reach the tectal region.

Pediatric tectal plate gliomas: a review of clinical outcomes, endocrinopathies, and neuropsychological sequelae

Pediatric tectal plate gliomas are indolent slow-growing gliomas that often present with increased intracranial pressure or incidentally on routine brain imaging. We investigated clinical outcomes, endocrinopathies, and neuropsychological sequelae associated with tectal plate gliomas. Twenty-six patients with tectal plate glioma were identified in a 20-year retrospective review. Clinical outcomes, treatments, endocrine function, neuropsychological testing outcomes and radiographic imaging were reviewed for possible signs correlating with tumor progression. Among 26 patients, 19 presented with signs or symptoms of increased intracranial pressure (73 %) versus an incidental finding in 7 (27 %). Median follow-up was 46 months (range 8-143 months). Six of 26 (23 %) experienced progressive disease after diagnosis. Five of 26 (19 %) required more than one surgical procedure due to failure of initial endoscopic third ventriculostomy. Seven of 26 had history of endocrine dysfunction, of which, five presented with endocrine dysfunction (precocious puberty or short stature), 1 developed menstrual irregularities after surgical intervention and 1 had preexisting pan hypopituitarism. Of 12 patients with available neuropsychological testing, eleven had at least one indicator of executive functioning in the low-average to impaired range. While tectal plate gliomas have been considered indolent tumors that are rarely progressive, 23 % of patients in our cohort experienced disease progression and required further therapy. Neurocognitive deficits may occur, while endocrine deficiency is uncommon. Regular multidisciplinary oncology follow-up, routine monitoring with MRI and formal neurocognitive evaluation are imperative to provide early recognition of disease progression or recurrent hydrocephalus and to improve school functioning in this population.

Complete response and long-term survival (>20 years) of a child with tectal glioma: a case report

Tectal glioma is a midbrain tumor. The patient generally presents with symptoms related to increased intracranial pressure and requires treatment for hydrocephalus. No effective pharmacological treatments have yet been introduced. This report discusses a case of a 13-year-old male diagnosed with tectal glioma who obtained a complete response and long-term survival after the treatment with antineoplastons (ANP) in phase II trial. Prior treatment consisted of placement of a ventriculoperitoneal shunt. After 6 years of stabilization there had been an increase in tumor size with signs of malignant transformation. The patient received treatment with ANP A10 and AS2-1 infusions for 20 months, obtained a complete response, and was switched to maintenance with ANP capsules. All treatments were discontinued in December 2003. Adverse events according to CTCAE v3.0 included: hypernatremia (two events of grade 3, one event of grade 2, four events of grade 1), one case of fatigue (grade 2), and one allergic reaction (grade 1). Currently, over 20 years from his diagnosis and over 13 years from treatment start he is symptom-free and leads a normal life. This report indicates that it is possible to obtain long-term survival of a child with tectal glioma with currently available investigational treatment.

Tectal plate tumours. Our experience with a paediatric surgical series

INTRODUCTION

Exophytic tectal plate tumours are a particular kind of brain stem tumour that can be treated with microsurgical resection. This paper reports our surgical experience with a paediatric series stressing and underlines the fact that this surgery can be possible because the rate of surgical mortality is low in experienced hands with acceptable morbidity.

MATERIAL AND METHODS

From 1997 to 2010, 27 patients were treated for exophytic tectal plate tumours. The clinical symptomatology was characterized by an intracranial hypertensive syndrome in 77% of cases, visual disorders in 36% of cases and a Parinaud's syndrome in 12% of cases. All patients were studied using a pre-operative cranio-spinal MRI with and without gadolinium. Hydrocephalus was present in 20 cases treated with a VP shunt in 6 cases and an ETV in the other cases. The surgical removal was total in 60% of cases, partial in 28% of cases and only a large biopsy in 12% of cases. From an histological point of view benign gliomas were diagnosed in 84% of cases and in 16% of cases were classified as WHO grade II and III. Eight patients needed complementary treatment, four with chemotherapy and four with chemotherapy associated to radiotherapy. As a surgical complication two patients had hydrocephalus, one patient had a sub-dural acute haematoma, two patients had an infectious complication requiring surgical treatment and antibiotic therapy, and 5 patients a mechanical shunt dysfunction. No post-surgical mortality was observed.

RESULTS

The most recent results after a median survival of 4.3 years show that 22 patients are still alive while 5 patients died of a progressive disease. Twenty patients in school age continue to follow a normal school programme but 10 patients need assistance.

CONCLUSION

Exophytic tectal plate tumours can be treated based on a microsurgical approach in paediatric patients. In experienced hands surgery can be performed with an acceptable morbidity and with zero percent mortality. In our experience, the sub-occipital transtentorial approach permits a wide view of the region and safe surgical removal.

Pineal region masses--imaging findings and surgical approaches

The anatomy of the pineal region is complex. Despite advances in surgical techniques since the first reported successful pineal region surgery in the early 20th century, pineal region surgery remains challenging owing to the proximity of deep cerebral veins and dorsal midbrain structures critical for vision. In this article, we review the relevant surgical anatomy of the pineal region and discuss historically important and current surgical approaches. We describe specific imaging features of pineal region masses that may affect surgical planning and review neoplastic and nonneoplastic masses that occur in the pineal region.

Correlation between MRI findings and histological diagnosis of brainstem glioma

OBJECTIVE

In most studies, treatment decisions of brainstem glioma are based solely on MRI features and do not incorporate a histopathological diagnosis. In the current study, we sought to compare MRI characteristics with histopathological findings of bainstem glioma.

METHODS

From April 2003 through April 2012, 150 patients were diagnosed with brainstem gliomas by MRI and microsurgically treated in Tiantan Hospital, Beijing, China. All the MRI and histopathological findings of these patients were respectively reviewed.

RESULTS

Of the 150 patients, 65 were female and 85 were male, 120 were adults and 30 were children (age < 18 years), 108 were low-grade glioma (72.0%), 35 were high-grade glioma (23.3%). The accuracy of the MRI diagnosis for brainstem glioma was 95.3%. Data analysis of the MRI findings revealed that a focal lesion was associated with a more favorable histopathological diagnosis in intrinsic (P=0.005) and exophytic (P=0.001) brainstem glioma patients. In the intrinsic diffuse type, tumors without enhancement had more favorable pathological findings (P=0.009).

CONCLUSIONS

To our knowledge, this is the largest case series of this nature reported in the literature to date. The results of this study suggest that MRI features of brainstem gliomas could predict some pathological features and guide prognosis, choice of biopsy and treatment modalities. The pathology of tumors with a focal appearance on MRI was associated with a prognosis that was significantly better than their diffuse counterparts. For the intrinsic diffuse gliomas, non-enhancing tumors had pathology suggestive of a favorable prognosis.

Pediatric tectal plate gliomas: clinical and radiological progression, MR imaging characteristics, and management of hydrocephalus

OBJECT

Tectal plate gliomas are generally low-grade astrocytomas with favorable prognosis, and observation of the lesion and management of hydrocephalus remain the mainstay of treatment.

METHODS

A cohort of patients with tectal plate gliomas at 2 academic institutions was retrospectively reviewed.

RESULTS

Forty-four patients with a mean age of 10.2 years who harbored tectal plate gliomas were included in the study. The mean clinical and radiological follow-up was 7.6 ± 3.3 years (median 7.9 years, range 1.5-14.7 years) and 6.5 ± 3.1 years (median 6.5 years, range 1.1-14.7 years), respectively. The most frequent intervention was CSF diversion (81.8% of patients) followed by biopsy (11.4%), radiotherapy (4.5%), chemotherapy (4.5%), and resection (2.3%). On MR imaging tectal plate gliomas most commonly showed T1-weighted isointensity (71.4%), T2-weighted hyperintensity (88.1%), and rarely enhanced (19%). The initial mean volume was 1.6 ± 2.2 cm(3) and it increased to 2.0 ± 4.4 cm(3) (p = 0.628) at the last follow-up. Frontal and occipital horn ratio (FOHR) and third ventricular width statistically decreased over time (p < 0.001 and p < 0.05, respectively).

CONCLUSIONS

The authors' results support existing evidence that tectal plate gliomas frequently follow a benign clinical and radiographic course and rarely require any intervention beyond management of associated hydrocephalus.

Tectal plate gliomas: a review

INTRODUCTION

Tectal plate gliomas are generally benign neoplastic lesions arising in the brainstem which can, with local extension, obstruct the aqueduct of Sylvius and lead to hydrocephalus.

ANATOMY

Diagnosis is based on initial suspicion fostered by the presentation of an obstructive hydrocephalus followed by physical exam which may potentially reveal indications of pyramidal tract dysfunction or cranial nerve palsies.

DISCUSSION

MRI studies reveal a characteristic well-circumscribed, isodense or hypodense mass on T1-weighted images, with hyperdensity on T2 imaging. Yet current radiological methods insufficiently distinguish tectal plate gliomas from brainstem tumors or gliomas in the neighboring structures, and a definitive diagnosis requires biopsy and histopathological analysis. Management is planned according to the degree of associated signs and symptoms, and may range from diligent observation and periodic screening for advancing tumor development, to cerebrospinal fluid shunting in an effort to resolve obstructive hydrocephalus, to radio- and chemotherapy. A wide range of minimally invasive approaches using endoscopy is available for the neurosurgeon, including endoscopic third ventriculostomy and endoscopic aqueductoplasty.

Brainstem gliomas

Historically, brainstem gliomas have been considered as a single entity. Since the introduction of magnetic resonance (MR) imaging in the late 1980s, these tumors are now regarded as a heterogeneous group of neoplasms with different age of onset, clinical and radiologic presentation, and varying behavior and natural history. This article describes the different subtypes of brainstem gliomas in children and adults. We focus on recent advances in MR such as MR spectroscopy, MR perfusion, and diffusion tensor imaging that often strongly suggest the histopathologic diagnosis of the lesion.

Brainstem glioma: a review

Brainstem gliomas (BGs) are a heterogenous group of gliomas that occur predominately in children. They can be separated into groups on the basis of anatomy and clinical behavior: diffuse intrinsic pontine glioma (DIPG), exophytic medullary glioma, and tectal glioma. DIPG is the commonest BG. Median age at onset is 6.5 years and median survival is less than 1 year. Adults with DIPG survive longer, suggesting a less aggressive and biologically different tumor from that in children. Patients present with cranial nerve dysfunction, long tract signs, or ataxia, either in isolation or in combination. Magnetic resonance imaging shows an infiltrative lesion occupying most of the pons and contrast enhancement is usually not prominent. Standard treatment is fractionated radiotherapy. Platelet-derived growth factor receptor alpha and epidermal growth factor receptor mutations have been identified. Inhibitors of these growth factor receptors are being evaluated in clinical trials. Exophytic medullary and tectal gliomas are relatively indolent tumors that can often be followed closely without treatment.

Feasibility, safety, and indications for surgical biopsy of intrinsic brainstem tumors in children

PURPOSE

Diffuse intrinsic pontine gliomas (DIPGs) are rapidly progressive and aggressive tumors that usually arise in children. Their anatomic location makes gross total surgical resection impossible, and fewer than 10% of patients survive more than 2 years after diagnosis. Often, these lesions are treated based on imaging characteristics alone. However, despite aggressive chemotherapy and radiation treatments available, prognosis remains poor. There is therefore a need for new therapies directed by biologic profiling. This necessitates a tissue diagnosis and, therefore, surgical biopsy. We have reviewed the results of biopsy for DIPGs in children at a single institution and compared our results to those available in the literature to elucidate the utility of biopsy for DIPGs.

METHODS

A historical cohort study was performed using medical records of patients under the age of 18 who underwent surgical biopsy of a DIPG at a single institution.

RESULTS

Nine patients were included, four males and five females. Age at presentation ranged from 8 months to 10 years (average 5.7 years). Pathologic diagnoses included five high grade (WHO grade III or IV) gliomas and four low grade (WHO grade II) astrocytomas. There were no intraoperative complications, and only one patient developed a new postoperative neurologic deficit.

CONCLUSIONS

Stereotactic biopsy of DIPGs is essential to obtain a pathologic diagnosis and is associated with low morbidity. This technique is important to elucidate biological characteristics of these tumors in order to direct multidisciplinary treatment plans possibly involving chemotherapy, radiation therapy, or other future clinical trial interventions for children with DIPGs.

Brain stem tumors in children and adolescents: single institutional experience

PURPOSE

Pediatric brain stem tumors (BsT) are a heterogeneous group of diseases. Our aim was to analyze our experience to find out prognostic factors.

METHOD

A retrospective study with BsT patients was performed. Imaging characteristics, extension of surgery, pathology, and adjuvant therapy were analyzed and correlated with overall survival (OS) and progression-free survival (PFS) as outcome measures.

RESULT

Since 1980 to 2010, we analyzed 65 BsT patients, 41 of them girls (63%), median age of 8 years (range 13.9 months to 17.6 years). Twenty-two patients (33.8%) had diffuse intrinsic pontine gliomas (DIPG) and 43 (66.2%) presented with focal BsT. Histology was available in 42 patients; the most frequent is low-grade glioma in 24/42 patients (57%). DIPG's histology (obtained usually at necropsy) confirmed five high-grade gliomas. After median follow-up of 49.3 months (0.5-175 months), 20/22 DIPG patients have died (90.9%), while 27/43 with focal tumors were alive (62.8%). Variables related to outcome were histology (better for low-grade glioma (LGG) OS p < 0.001), surgery (better if operated OS p < 0.001), and adjuvant therapy (worse if given, PFS p = 0.001, OS p = 0.024). The outcome for DIPG was dismal, median OS/EFS of 14.2/9.4 months, significantly worse than focal BsT (p = 0.000), while OS/EFS was 122.8/87.2 months for focal intrinsic, 88.2/47.1 months for exophytic, and 124.4/54 months for cervico-medullary tumors: no differences were found among them, except the histology (OS p < 0.001 for low-grade vs high-grade tumors).

CONCLUSION

BsT in children comprised two different groups: diffuse (DIPG) and focal gliomas. The DIPGs continue having a dismal prognosis, needing new approaches, while focal tumors including LGG have better prognosis.

Conventional and advanced MRI features of pediatric intracranial tumors: posterior fossa and suprasellar tumors

OBJECTIVE

In this article, we review the most common posterior fossa and suprasellar intracranial neoplasms in the pediatric population. We briefly discuss basic MRI concepts used in the initial evaluation of a pediatric brain tumor and then discuss sophisticated MRI techniques that give insight into the physiology and chemical makeup of these tumors to help the radiologist make a more specific diagnosis.

CONCLUSION

Diagnosis and treatment of pediatric CNS tumors necessitate a multi-disciplinary approach and require expertise and diligence of all parties involved. Imaging is an essential component has evolved greatly over the past decade. We are becoming better at making a preoperative diagnosis of that tumor type, detecting recurrence, and guiding surgical management to avoid injury to vital brain structures.

Long-term change in ventricular size following endoscopic third ventriculostomy for hydrocephalus due to tectal plate gliomas

OBJECT

Endoscopic third ventriculostomy (ETV) is an alternative to shunt placement in children with hydrocephalus due to tectal plate gliomas (TPGs). However, controversy remains regarding the amount of ventricular size reduction that should be expected after ETV. This study investigates ventricular size change after ETV for TPGs.

METHODS

Twenty-two children were identified from a 15-year retrospective database of neuroendoscopic procedures performed at the authors' institution, Children's Hospital of Alabama, in patients with a minimum of 1 year of follow-up. Clinical outcomes, including the need for further CSF diversion and symptom resolution, were recorded. The frontal and occipital horn ratio (FOR) was measured on pre- and postoperative, 1-year, and last follow-up imaging studies.

RESULTS

In 17 (77%) of 22 children no additional procedure for CSF diversion was required. Of those in whom CSF diversion failed, 4 underwent successful repeat ETV and 1 required shunt replacement. Therefore, in 21 (96%) of 22 patients, CSF diversion was accomplished with ETV. Preoperative and postoperative imaging was available for 18 (82%) of 22 patients. The FOR decreased in 89% of children who underwent ETV. The FOR progressively decreased 1.7%, 11.2%, and 12.7% on the initial postoperative, 1-year, and last follow-up images, respectively. The mean radiological follow-up duration for 18 patients was 5.4 years. When ETV failed, the FOR increased at the time of failure in all patients. Failure occurred 1.6 years after initial ETV on average. The mean clinical follow-up period for all 22 patients was 5.3 years. In all cases clinical improvement was demonstrated at the last follow-up.

CONCLUSIONS

Endoscopic third ventriculostomy successfully treated hydrocephalus in the extended follow-up period of patients with TPGs. The most significant reduction in ventricular size was observed at the the 1-year followup, with only modest reduction thereafter.

Favorable outcome with conservative treatment for children with low grade brainstem tumors

BACKGROUND

Pediatric brainstem tumors (BST) comprise a heterogeneous group of entities. Data regarding treatment options and outcome of BST, specifically brainstem low grade tumors (BSLGT) are limited. In order to better define risk groups and evaluate treatment options for pediatric BST, we performed a comprehensive analysis of all BST patients treated in our hospital during the MRI era.

PROCEDURES

We retrospectively analyzed clinical, imaging, and pathology data at presentation, treatment, and outcome of all BST patients followed at the Hospital for Sick Children in Toronto over the last 25 years.

RESULTS

Of 1,801 children with brain tumors, 223 (12%) had a brainstem primary location. Tumors without pontine involvement were BSLGT in 98.3%, whereas 75% of tumors involving the pons were high grade (P = 0.0001). Patients with BSLGT had 5-year progression-free survival (PFS) and overall survival (OS) of 57 ± 3% and 89 ± 5%, respectively. Upfront observation of tumor residual conferred no survival disadvantage with 5-year PFS and OS of 57 ± 5% and 93 ± 3%, respectively. In the group of patients requiring further treatment, 5-year PFS and OS were comparable between chemotherapy and radiotherapy with 53 ± 12% and 93 ± 4% and 66 ± 11% and 83 ± 6%, respectively (P = 0.26 and 0.3, respectively).

CONCLUSION

BST without pontine involvement are almost invariably BSLGT. Children with BSLGT have an excellent outcome even with careful initial observation. No clear benefit was observed for radiotherapy over chemotherapy when adjuvant treatment was needed. A conservative approach may be warranted for children with non-pontine brainstem lesions.

Adult brainstem gliomas

Brainstem gliomas are uncommon in adults and account for only 1%-2% of intracranial gliomas. They represent a heterogeneous group of tumors that differ from those found in their pediatric counterparts. In adults, a low-grade phenotype predominates, which is a feature that likely explains their better prognosis compared to that in children. Because biopsies are rarely performed, classifications based on the radiological aspect of magnetic resonance imaging results have been proposed to establish treatment strategies and to determine outcomes: (a) diffuse intrinsic low-grade, (b) enhancing malignant glioma, (c) focal tectal gliomas, and (d) exophytic gliomas. Despite significant advances in neuroradiology techniques, a purely radiological classification remains imperfect in the absence of a histological diagnosis. Whereas a biopsy may often be reasonably avoided in the diffuse nonenhancing forms, obtaining histological proof seems necessary in many contrast-enhanced brainstem lesions because of the wide variety of differential diagnoses in adults. Conventional radiotherapy is the standard treatment for diffuse intrinsic low-grade brainstem gliomas in adults (the median survival is 5 years). In malignant brainstem gliomas, radiotherapy is the standard treatment. However, the possible benefit of combined radiotherapy and chemotherapy (temozolomide or other agents) has not been thoroughly evaluated in adults. The role of anti-angiogenic therapies in brainstem gliomas remains to be defined. A better understanding of the biology of these tumors is of primary importance for identifying homogeneous subgroups and for improving therapy options and outcomes.

Pediatric low-grade gliomas

Pediatric low-grade gliomas encompass a heterogeneous set of tumors of different histologies. Cerebellar pilocytic astrocytomas occur most frequently followed by supratentorial diffuse fibrillary astrocytomas. Recent research has implicated activation of the RAS/RAF/MEK pathway in tumorigenesis of these tumors. Surgery is the mainstay of therapy. Overall survival rates for patients whose tumors are completely resected are 90% or greater, 10 years from diagnosis. Conversely, most optic pathway/hypothalamic, deep midline, and brain stem gliomas have minimal potential for resection; these tumors can be difficult to treat and deserve special attention. Combination chemotherapy is currently recommended as front-line adjuvant treatment for progressive or recurrent tumors. Second-line radiotherapy can also improve overall survival but is associated with more frequent and significant neurocognitive, endocrine, and other long-term toxicities.

6-year-old girl with hydrocephalus

With rare exceptions, pediatric tectal gliomas have been generally reported as low-grade tumors with relatively good prognosis. The patients are usually treated conservatively to manage the signs and symptoms of obstructive hydrocephalus. We report a case of a tectal glioma in a 6-years-old girl with histological features of anaplastic mixed oligoastrocytoma that continues to progress despite chemotherapy and radiation therapy.

Brainstem gliomas in children and adults

PURPOSE OF REVIEW

The purpose of this review is to determine if recent advances in diagnostic and treatment modalities result in improvement in the pattern of care of brainstem gliomas.

RECENT FINDINGS

New MRI techniques may contribute to differential diagnosis and aid neurosurgeons in removing resectable brainstem tumors. A better radiological analysis of these heterogeneous tumors improves their classification and helps to better distinguish prognosis subgroups. However, biopsy remains indicated in many contrast enhancing brainstem masses in adults because of the great variety of differential diagnosis.

SUMMARY

Diffuse brainstem glioma is the most common subtype of brainstem tumor and remains a devastating malignancy in children. Conventional radiotherapy is the standard of care and chemotherapy has been disappointing to date. Given the lack of efficacy of conventional drugs, a better understanding of the biology of this tumor is the key to more targeted therapy.

Indolent dorsal midbrain tumor: new findings based on positron emission tomography

OBJECT

Intrinsic tumors arising in the dorsal midbrain cause obstructive hydrocephalus and have an indolent clinical course. Positron emission tomography (PET) with fluorine-18-labeled fluorodeoxyglucose (FDG) and l- [methyl-(11)C]methionine (MET) was used to evaluate the biological behaviors of dorsal midbrain tumors.

METHODS

The authors report on 4 patients (3 males and 1 female) with dorsal midbrain tumors who presented with obstructive hydrocephalus. A diagnosis was made with MR imaging in each patient. To manage the hydrocephalus, endoscopic third ventriculostomy was performed in all cases. The patients did not undergo any other surgical procedures except endoscopic biopsy procedure, chemotherapy, or radiation therapy. The patients in 3 cases underwent FDG- and MET-PET within 6 months of CSF-diverting procedures, and the patient in 1 case underwent PET 10 years after the procedure.

RESULTS

After the CSF-diverting procedure, clinical symptoms resolved or improved in all patients. Gliosis or glial proliferation was diagnosed in 1 patient, and possible low-grade glioma in 2 patients. Although all tumors appeared hyperintense on T2-weighted MR images, their appearance on T1-weighted images was variable (iso- and/or hypointense), and partial lesion enhancement was observed on images from 2 patients. On the other hand, the PET features of these lesions were almost identical, and the scans did not show a high uptake of FDG and MET compared with the cortical uptake in a normal brain. The mean tumor tissue/normal tissue ratio of FDG uptake was 0.65, and that of MET was 0.99.

CONCLUSIONS

Positron emission tomography findings suggested that the indolent dorsal midbrain lesion had nontumorous characteristics, thus supporting a good prognosis. Positron emission tomography studies may be more informative and predictive of the biological behavior of dorsal midbrain tumors than a biopsy procedure.

Tectal glioblastoma

Brain stem gliomas are a heterogeneous group of neoplasms arising mostly in paediatric patients. Tectal plate gliomas represent a particular type of brain stem tumours usually with a benign, indolent clinical course, presenting with signs of raised intracranial hipertension due to supra-tentorialhydrocephalous caused by aqueductal stenosis. Seldom high-grade lesions arise in this location with tremendous therapeutic implications. When a malignant tumour is clinically and radiographically suspected a biopsy should be performed to obtain histhological confirmation. Treatment is then planned in a case-by-case basis. We present the case of a glioblastoma of the tectal plate in a 22 years-old woman operated upon by a supracerebellar-infratentorial approach.

Treatments for astrocytic tumors in children: current and emerging strategies

Strategies for the treatment of childhood cancer have changed considerably during the last 50 years and have led to dramatic improvements in long-term survival. Despite these accomplishments, CNS tumors remain the leading cause of death in pediatric oncology. Astrocytic tumors form the most common histologic group among childhood brain tumors. They are a heterogeneous group that from a practical therapeutic point of view can be subdivided into low-grade astrocytomas (LGA), optic pathway gliomas (OPG), high-grade astrocytomas (HGA), and brainstem gliomas (BSG). This article focuses on the practical application of treatments that lead to long-term survival, improved quality of life, and reduced long-term complications. Improvement in therapy has led to better outcomes for patients with LGA and OPG. Careful follow-up without any treatment is indicated for a small percentage of patients diagnosed with LGA with an indolent course including children with neurofibromatosis type 1 (NF1). Surgery is the main recommended treatment for children with resectable LGA. Radiation therapy is generally recommended for children with progressive LGA, or after failure of chemotherapy, accomplishing tumor control at 10 years in over 60% of patients. Cytotoxic chemotherapy is usually reserved for children who have had treatment failure with surgery and radiation therapy. It is also offered for children who are too young to be treated with radiation or to defer or avoid radiotherapy. Carboplatin and vincristine achieve 5% complete and 28% partial responses but the use of vincristine is criticized due to poor penetration of the CNS. A regimen of tioguanine, procarbazine, mitolactol, lomustine, and vincristine is frequently administered as an alternative to carboplatin and vincristine in LGA. The introduction of temozolomide has allowed better responses, including a 24% complete response rate compared with 0-5% complete response rates with the previous regimens. OPG are usually histologically LGA, and are treated with similar chemotherapy regimens. OPG is the most common type of brain tumor associated with NF1. Tumor growth in some of these patients is slow with no treatment recommended for an extended period of time. The prognosis for children with the remaining types of astrocytomas remains poor. Surgical resection is typically the first step in the treatment of HGA followed in older children by radiation therapy. The data regarding chemotherapy are mixed. Combination chemotherapy before or after radiation, including cisplatin, carmustine, cyclophosphamide, and vincristine or carboplatin, ifosfamide, cyclophosphamide, and etoposide has provided disappointing results. Clinical trials with temozolomide and agents directed against single targets have not shown substantially better results, but it is hoped that currently conducted studies will provide better outcomes. Diffuse intrinsic BSG are among the most difficult-to-treat brain tumors. Surgical treatment is not recommended for diffuse intrinsic BSG and standard radiation therapy is typically given in children aged >3 years. None of the numerous chemotherapy regimens, including temozolomide, has provided a significant response rate or an improvement in survival. It is expected that newer agents affecting multiple targets such as AEE-788 and antineoplastons, and combinations of single-targeted agents with chemotherapy will provide better results. Careful evaluation of histology, location of the tumor, patient age, and consideration of treatment-related morbidity play an important part in selecting between clinical observation, surgery, radiation, chemotherapy, or investigational agents. The goals of treatment for astrocytic tumors should extend well beyond objective responses and increased survival. Improvement of quality of life is an equally important objective of treatment. Radiation therapy and chemotherapy result in serious late toxicities.

Management of pineal region tumors

Tumors of the pineal region represent a diverse collection of tumors with a variety of natural histories. This diversity necessitates accurate histologic diagnosis to allow rational therapeutic planning. Evaluation of a pineal lesion should begin with craniospinal MRI and analysis of the cerebrospinal fluid (CSF). Whereas certainty of the histologic diagnosis is now a requirement for treatment in Western nations, some Asian centers continue to recommend a test dose of radiation therapy based on the high incidence of germinoma in those countries. If there is high clinical suspicion of a germinoma or tectal glioma, stereotactic or endoscopic biopsy may be pursued. All other lesions should be referred for open biopsy with microsurgical techniques. This approach provides adequate tissue for diagnosis, may be curative in low-grade tumors, and may substantially improve survival in patients with malignant tumors. If open surgery is not desired by the patient or practitioner, stereotactic or endoscopic biopsy may be followed by radiosurgery for localized, well-demarcated tumors. Radiation therapy is the first-line therapy for germinomas. Although the optimal radiation dosage and volume have not been decided, the current Children's Oncology Group trial may offer definitive evidence to address this dilemma in germ cell tumors. Evidence of CSF seeding requires craniospinal radiation and adjuvant chemotherapy regardless of tumor type. Diagnosis of any of the malignant tumors (non-germ cell tumors, pineoblastomas, and parenchymal tumors of intermediate determination) also requires craniospinal radiation (with local tumor doses of at least 50 Gy) and adjuvant chemotherapy (generally platinum based). Patients with tectal gliomas may undergo excision with or without postoperative radiation; however, they also may be observed with vigilant follow-up alone.

Total Resection of a Hemorrhagic Tectal Pilocytic Astrocytoma-Case Report-

A 21-year-old man presented with a hemorrhagic pilocytic astrocytoma of the tectal plate manifesting as sudden onset of severe headache, vertigo, nausea, and vomiting. Computed tomography demonstrated acute hydrocephalus and hemorrhage within the brain stem and fourth ventricle. Magnetic resonance (MR) imaging revealed a dorsally exophytic tectal tumor as hypointense on the T(1)-weighted image and hyperintense on the T(2)-weighted image with contrast enhancement. Radical resection of the tumor was selected because of the unusual aggressive clinical course with hemorrhage and suspicion of malignant components. The tumor was totally resected via an occipital transtentorial approach using a neuronavigation system without surgical complications. The histological diagnosis was pilocytic astrocytoma. The patient was discharged home without neurological deficits on the 9th postoperative day. Twenty-three months after the surgery, follow-up MR imaging demonstrated no recurrence. Tectal plate pilocytic astrocytoma is rarely associated with hemorrhage but should be considered in the differential diagnosis of intracranial hemorrhage with acute presentation. Such exceptional tectal tumors should be resected radically and undergo histological examination to decide on further appropriate treatment.

Gamma Knife surgery for focal brainstem gliomas

Object

Focal tumors, a distinct subgroup of which is composed of brainstem gliomas, may have an indolent clinical course. In the past, their management involved monitoring of open-ended imaging studies and shunt placement if cerebrospinal fluid diversion was required. Nonetheless, their treatment remains a significant challenge for neurosurgeons. Gamma Knife surgery (GKS) has recently been tried as an alternative to surgical extirpation. In the present study the authors assess clinical and imaging results in 20 patients who harbored focal brainstem gliomas treated with GKS between 1990 and 2001.

Methods

There were 10 male and 10 female patients with a mean age of 19.1 years. Sixteen tumors were located in the midbrain, three in the pons, and one in the medulla oblongata. The mean tumor volume at the time of GKS was 2.5 cm3. In 10 cases a tumor specimen was obtained either by open surgery or stereotactic biopsy, securing the diagnosis of pilocytic astrocytoma in five patients and nonpilocytic astrocytoma in five others. In the remaining 10 cases, the diagnosis was based on clinical and neuroimaging findings. The prescription Gamma Knife dose varied between 10 and 18 Gy, except in three patients who were receiving a boost to a site in which external-beam radiation was previously delivered. An average of four isocenters were utilized per GKS.

Patients were followed up for a mean of 78.0 months. The tumors disappeared in four patients and shrank in 12 patients. Of these patients, one experienced transitory extrapyramidal symptoms and fluctuating impairment of consciousness (from somnolence to coma) for 6 months. Another patient whose tumor disappeared 3 years following GKS died of stroke 8 years postoperatively. The rest of the patients either remained stable or improved clinically. Tumor progression occurred in four patients; of these four, one patient developed hydrocephalus requiring a ventriculoperitoneal shunt, two showed neurological deterioration, and one 4-year-old boy died of tumor progression.

Conclusions

Gamma Knife surgery may be an effective primary treatment or adjunct to open surgery for focal brainstem gliomas.

Brainstem tumors: where are we today?

Brainstem tumors comprise 10-20% of all pediatric central nervous system tumors. The management of these tumors has evolved dramatically in the past century. Once considered uniformly fatal, it is now known that brainstem tumors have distinguishing characteristics and do not behave identically. The focality and location of the lesion is determined from the clinical history, presentation, and associated imaging. Based on these findings, it is possible to predict the behavior of the tumor and choose an appropriate intervention. Focal lesions have a good prognosis and are treated operatively while diffuse lesions have a poor prognosis and are managed medically. This article reviews the current classification of brainstem tumors, current management options and future directions for the treatment of these rare tumors.