Impact of location on outcome in children with low-grade oligodendroglioma

Temporal Glioblastoma Mimicking Basal Ganglia Invasion: Distinguishing Removable and Unremovable Tumors

OBJECTIVE

Maximal safe resection prolongs the survival of patients with glioblastoma (GB). However, whether total resection of the enhanced lesion is pursued or abandoned depends on preoperative judgments based on the findings of magnetic resonance imaging (MRI). Anatomically, medial temporal tumor tends to invade toward the temporal stem, insula, and basal ganglia, representing tumor with high surgical risk. In the present study, we describe the key radiologic features of medial temporal GB to achieve extent of resection.

METHODS

We reviewed all GB cases located in the temporal lobe (tGB) treated between April 2013 and March 2018 at Kitasato University Hospital. On the basis of MRI, tGB was simply classified into 3 groups: medial tGB and nonmedial tGB, and medial tGB was further subdivided into invading type and mimicking type. We focused on the resectability of medial tGB.

RESULTS

Twenty-seven patients with tGB were identified. Twenty were included in the nonmedial tGB, and 7 were in the medial tGB. All medial tGB seemed to invade into the basal ganglia and/or the lenticulostriate arteries, but detailed examination revealed 2 types of tumor, invading type (3 cases) and mimicking type (4 cases). The invading type had true involvement of the basal ganglia and/or lenticulostriate arteries, whereas the mimicking type had no involvement of these structures. This new classification is highly effective, as the former is unresectable, but the latter is totally resectable.

CONCLUSIONS

Medial tGB is a challenging tumor for maximal safe resection, so our classification will help to identify cases of removable medial tGB.

Prognostic Significance of Anatomic Origin and Evaluation of Survival Statistics of Astrocytoma Patients-a Tertiary Experience

Astrocytoma constitutes the most noted malignancies of the central nervous system with worse clinical outcomes in grade IV astrocytoma or glioblastoma multiforme. Owing to poor clinical outcomes with existing therapeutic regime, there is a need to revisit the initial course of treatment. Statistical information of clinicopathological parameters could be used to understand the spread of disease and, in turn, to formulate updated treatment management. In the present study, we have seen anatomic distribution of astrocytoma subtypes in a group of 479 patients and correlated it with survival outcomes. Anatomic location was confirmed by MRI (magnetic resonance imaging) images. A registry of patients was maintained with clinicopathological details as tumor type, location, age/sex, and survival after surgery. We have observed overall survival particulars in patients diagnosed with astrocytoma. Our findings highlight that in total cases, tumor location was anatomically dominated by frontal and temporal lobes. Survival analysis in high-grade (grade III, p = 0.03; grade IV, p = 0.01) astrocytic tumors confirms poor outcomes with temporal, parietal, and occipital location as compared to frontal lobe. Overall survival study demonstrates glioblastoma multiforme (GBM) was associated with worse prognosis as compared to astrocytoma subtypes (p < 0.0001). In high-grade astrocytomas, anaplastic astrocytoma was found with 34 months of median survival age while 14 months in the case of patients with glioblastoma multiforme. In conclusion, we report dismal prognosis in parietal, temporal, and occipital lobes in grade II, grade III, and grade IV astrocytoma patients. Among astrocytoma subtypes, patients with glioblastoma multiforme were associated with worse survival outcomes. We uniquely feature the survival of astrocytoma patients for the first time and observe GBM patients have slightly longer survival.

Predictors of clinical outcome in pediatric oligodendroglioma: meta-analysis of individual patient data and multiple imputation

OBJECTIVE Oligodendroglioma is a rare primary CNS neoplasm in the pediatric population, and only a limited number of studies in the literature have characterized this entity. Existing studies are limited by small sample sizes and discrepant interstudy findings in identified prognostic factors. In the present study, the authors aimed to increase the statistical power in evaluating for potential prognostic factors of pediatric oligodendrogliomas and sought to reconcile the discrepant findings present among existing studies by performing an individual-patient-data (IPD) meta-analysis and using multiple imputation to address data not directly available from existing studies. METHODS A systematic search was performed, and all studies found to be related to pediatric oligodendrogliomas and associated outcomes were screened for inclusion. Each study was searched for specific demographic and clinical characteristics of each patient and the duration of event-free survival (EFS) and overall survival (OS). Given that certain demographic and clinical information of each patient was not available within all studies, a multivariable imputation via chained equations model was used to impute missing data after the mechanism of missing data was determined. The primary end points of interest were hazard ratios for EFS and OS, as calculated by the Cox proportional-hazards model. Both univariate and multivariate analyses were performed. The multivariate model was adjusted for age, sex, tumor grade, mixed pathologies, extent of resection, chemotherapy, radiation therapy, tumor location, and initial presentation. A p value of less than 0.05 was considered statistically significant. RESULTS A systematic search identified 24 studies with both time-to-event and IPD characteristics available, and a total of 237 individual cases were available for analysis. A median of 19.4% of the values among clinical, demographic, and outcome variables in the compiled 237 cases were missing. Multivariate Cox regression analysis revealed subtotal resection (p = 0.007 [EFS] and 0.043 [OS]), initial presentation of headache (p = 0.006 [EFS] and 0.004 [OS]), mixed pathologies (p = 0.005 [EFS] and 0.049 [OS]), and location of the tumor in the parietal lobe (p = 0.044 [EFS] and 0.030 [OS]) to be significant predictors of tumor progression or recurrence and death. CONCLUSIONS The use of IPD meta-analysis provides a valuable means for increasing statistical power in investigations of disease entities with a very low incidence. Missing data are common in research, and multiple imputation is a flexible and valid approach for addressing this issue, when it is used conscientiously. Undergoing subtotal resection, having a parietal tumor, having tumors with mixed pathologies, and suffering headaches at the time of diagnosis portended a poorer prognosis in pediatric patients with oligodendroglioma.

Mortality in children with low-grade glioma or glioneuronal tumors: A single-institution study

BACKGROUND

While pediatric low-grade glioma/glioneuronal tumors (LGG/LGGNTs) are considered slow-growing, indolent tumors with excellent long-term prognosis, mortality due to the disease is not unknown. Few studies have addressed the cause of death in this population.

METHODS

Retrospective review of clinicopathologic and radiologic data for children 21 years or younger with LGG/LGGNT who died at St. Jude Children's Research Hospital between April 1985 and June 2015. Our primary objective was to determine the causes and timing of mortality in affected children.

RESULTS

For the 87 eligible patients, median age at diagnosis was 7.7 years (range, 0.21-21 years), median age at death was 14.26 years (range, 0.58-32 years), and median time to death from diagnosis was 4.02 years (range, 0.21-24 years). Midbrain/thalamus was the most common tumor location (n = 34), followed by suprasellar/hypothalamic (n = 18) and cerebrocortical (n = 13). Astrocytoma not otherwise specified (n = 24), pilocytic astrocytoma (n = 23), and fibrillary astrocytoma (n = 11) were the predominant histologic diagnoses. Causes of death included progressive primary disease (PD) (n = 43), progression of PD with histological features of a high-grade glioma at progression or at autopsy (PD-HGG) (n = 15), second cancer (n = 3), suicide (n = 4), and vehicular accident (n = 3). Among the 15 patients with PD-HGG, 12 received radiation therapy before histologic confirmation of progression.

CONCLUSIONS

PD and PD-HGG contributed to 66% of the mortality in our patient cohort. Early psychological intervention should be included as part of the multidisciplinary management approach of children with LGG/LGGNT to reduce the risk of suicide in vulnerable subjects.

Pediatric Thalamic Gliomas: An Updated Review

CONTEXT

- Neoplasms originating in the thalamus are rare overall (1% of all brain tumors); however, they comprise approximately 5% of pediatric intracranial tumors and approach 15% of all malignant pediatric intracranial tumors in some series.

OBJECTIVE

- To update readers about the current understanding of the diverse histology, biology, and behavior of pediatric thalamic tumors. Histologic verification is now thought to be critical for planning treatment, and, as a result, biopsy and total/subtotal resections are much more common today than in the past.

DATA SOURCES

- A PubMed search using the keywords "pediatric + thalamic + glioma" yielded 45 publications with a total of 445 cases of thalamic gliomas in patients less than 18 years of age. We found only 9 substantial institutional series tabulating all encountered thalamic histologic types in children. This survey confirmed a high proportion of astrocytomas, 81% (214 of 265), of which approximately two-thirds were diffuse astrocytomas (146 of 214) and one-third were pilocytic astrocytomas (68 of 214). Of the diffuse astrocytomas, 34% (49 of 146) were low grade (World Health Organization grade II) and 55% (81 of 146) were high grade (World Health Organization grade III or IV), making the latter subgroup the largest single category of all pediatric thalamic tumors. Oligodendrogliomas and ependymomas (mostly anaplastic in both cases) comprised 10% and 3% of all pediatric thalamic tumors, respectively.

CONCLUSIONS

- Tissue diagnosis is now thought crucial for prognostication and treatment, particularly as more potentially therapeutic molecular targets are discovered. Secure diagnosis allows identification of tumors for which resection is more feasible and beneficial.

Identification and targeting of an FGFR fusion in a pediatric thalamic "central oligodendroglioma"

Approximately 1–5% of pediatric intracranial tumors originate in the thalamus. While great strides have been made to identify consistent molecular markers in adult oligodendrogliomas, such as the 1p/19q co-deletion, it is widely recognized that pediatric oligodendrogliomas have a vastly different molecular make-up. While pediatric thalamic or “central oligodendrogliomas” are histologically similar to peripheral pediatric oligodendrogliomas, they are behaviorally distinct and likely represent a cohesive, but entirely different entity. We describe a case of a 10-year-old girl who was diagnosed with an anaplastic glioma with features consistent with the aggressive entity often diagnosed as central or thalamic oligodendroglioma. We performed whole-exome (paired tumor and germline DNA) and transcriptome (tumor RNA) sequencing, which demonstrated an FGFR3-PHGDH fusion. We describe this fusion and our rationale for pursuing personalized, targeted therapy for the patient’s tumor that may potentially play a role in the treatment of similar cases.

Oligodendrogliomas in Children: Clinical Experiences With 20 Patients

Oligodendrogliomas occurring rarely in children are incompletely characterized. The purpose of this study was to identify prognostic factors affecting the local control and survival in the management of children with oligodendrogliomas. We retrospectively analyzed clinical data on 20 pediatric patients with oligodendrogliomas treated at Chang Gung Children's Hospital between 1994 and 2014. There were 12 males and 8 females with a median age of 9.2 years at diagnosis (range, 3 mo to 18 y). Eighteen (90%) tumors were located in the cerebral hemispheres, 10 cases were located on the right, 8 on the left. One was located in the third ventricle and 1 in the thoracic spine. Presenting symptoms included seizures (n=7), headache (n=5), visual field defects (n=3), limb weakness (n=2), vomiting (n =1), back pain (n=1), and increased head circumference (n=1). All patients underwent craniotomy: 8 gross total resections, 8 subtotal resections, and 4 biopsies. Nine of the patients had pure oligodendroglioma and 11 had anaplastic oligodendroglioma (WHO grade III or IV). Ten children had adjuvant therapy including radiation (n=7), chemotherapy (n=1) or both (n=2). With the median follow-up of 5.3 years (range, 1.2 to 14.7 y), the 5-year overall survival and disease-free survival rates were 78.9% with 65.0%, respectively. Total tumor resection offers better overall survival regardless of the histologic grading. Our data demonstrate that patients with less than gross total resections are at increased risk for progression and may benefit from more aggressive therapy.

Conventional and advanced (DTI/SWI) neuroimaging findings in pediatric oligodendroglioma

PURPOSE

Oligodendroglioma are rare pediatric brain tumors. The literature about neuroimaging findings is scant. A correct presurgical diagnosis is important to plan the therapeutic approach. Here, we evaluated the conventional and advanced neuroimaging features in our cohort of pediatric oligodendrogliomas and discuss our findings in the context of the current literature.

METHODS

Clinical histories were reviewed for tumor grading, neurologic manifestation, treatment, and clinical status at the last follow-up. Neuroimaging studies were retrospectively evaluated for tumor morphology and characteristics on conventional and advanced magnetic resonance imaging (MRI).

RESULTS

Five children with oligodendroglioma were included in this study. Four children were diagnosed with a low-grade oligodendroglioma. The location of the tumors included the frontal and temporal lobe in two cases each and the fronto-parietal lobe in one. In all oligodendrogliomas, tumor margins appeared sharp. In the high-grade oligodendroglioma, a cystic and partially hemorrhagic component was seen. In all children, the tumor showed a T1-hypointense and T2-hyperintense signal. The signal intensity on fluid attenuation inversion recovery (FLAIR) images was hyperintense in four and mixed hypo-hyperintense in one child. The anaplastic oligodendroglioma showed postcontrast enhancement and decreased diffusion while the low-grade oligodendrogliomas showed increased diffusion. One low-grade oligodendroglioma showed calcifications on susceptibility weighted imaging.

CONCLUSION

Conventional MRI findings of pediatric oligodendrogliomas are nonspecific. Advanced MRI sequences may differentiate (1) low-grade and high-grade pediatric oligodendrogliomas and (2) pediatric oligodendrogliomas and other brain tumors.

Brainstem oligodendroglial tumors in children: two case reports and review of literatures

PURPOSE

There is little information on pediatric oligodendroglial tumor located in the brainstem because of its rarity.

METHODS

Here, we present two pediatric cases of pontine oligodendroglial tumors with radiological findings atypical for diffuse intrinsic pontine glioma.

RESULTS

The first patient was an 8-year-old boy. Brain magnetic resonance imaging (MRI) demonstrated diffuse high-intensity changes in the pons, left middle cerebellar peduncle, and part of the left cerebellar hemisphere on T2-weighted and fluid-attenuated inversion recovery images, with an enhanced spot lesion in the left cerebellar hemisphere. The pathological diagnosis was anaplastic oligodendroglioma, and we identified a mutation in histone H3.3 in the tumor specimen. He succumbed to massive disseminated relapse 7 months from diagnosis despite local radiation therapy. The second patient, a 2-year-old girl, was diagnosed with oligoastrocytoma. Brain MRI revealed a large mass in her rostral pons extended to the fourth ventricle with obstructive hydrocephalus. The tumor recurred with intracranial dissemination 56 months post-surgery.

CONCLUSIONS

Pediatric brainstem oligodendroglial tumors can include histone H3.3-mutated tumors and have a tendency to disseminate throughout the neuroaxis at the time of relapse.

Predicting the "usefulness" of 5-ALA-derived tumor fluorescence for fluorescence-guided resections in pediatric brain tumors: a European survey

BACKGROUND

Five-aminolevulinic acid (Gliolan, medac, Wedel, Germany, 5-ALA) is approved for fluorescence-guided resections of adult malignant gliomas. Case reports indicate that 5-ALA can be used for children, yet no prospective study has been conducted as of yet. As a basis for a study, we conducted a survey among certified European Gliolan users to collect data on their experiences with children.

METHODS

Information on patient characteristics, MRI characteristics of tumors, histology, fluorescence qualities, and outcomes were requested. Surgeons were further asked to indicate whether fluorescence was "useful", i.e., leading to changes in surgical strategy or identification of residual tumor. Recursive partitioning analysis (RPA) was used for defining cohorts with high or low likelihoods for useful fluorescence.

RESULTS

Data on 78 patients <18 years of age were submitted by 20 centers. Fluorescence was found useful in 12 of 14 glioblastomas (85 %), four of five anaplastic astrocytomas (60 %), and eight of ten ependymomas grades II and III (80 %). Fluorescence was found inconsistently useful in PNETs (three of seven; 43 %), gangliogliomas (two of five; 40 %), medulloblastomas (two of eight, 25 %) and pilocytic astrocytomas (two of 13; 15 %). RPA of pre-operative factors showed tumors with supratentorial location, strong contrast enhancement and first operation to have a likelihood of useful fluorescence of 64.3 %, as opposed to infratentorial tumors with first surgery (23.1 %).

CONCLUSIONS

Our survey demonstrates 5-ALA as being used in pediatric brain tumors. 5-ALA may be especially useful for contrast-enhancing supratentorial tumors. These data indicate controlled studies to be necessary and also provide a basis for planning such a study.

Clinicopathologic features of pediatric oligodendrogliomas: a series of 50 patients

Oligodendrogliomas are an important adult form of diffuse gliomas with a distinctive clinical and genetic profile. Histologically similar tumors occurring rarely in children are incompletely characterized. We studied 50 patients with oligodendrogliomas (median age at diagnosis 8 y, range 7 mo to 20 y). Tumors resembling dysembryoplastic neuroepithelial tumors or pilocytic astrocytomas or those having a "mixed" histology were excluded. Tumors at first diagnosis were low grade (n=38) or anaplastic (n=12). Histologic features included uniform round cells with perinuclear halos (100%), secondary structures (predominantly perineuronal satellitosis) (90%), calcifications (46%), and microcysts (44%). Sequential surgical specimens were obtained in 8 low-grade oligodendroglioma patients, with only 1 progressing to anaplasia. Studies for 1p19q performed in 40 cases demonstrated intact 1p19q loci in 29 (73%), 1p19q codeletion in 10 (25%), and 1p deletion with intact 19q in 1 (2%). Except for 2 young patients (3 and 11 y of age), patients with 1p19q codeletion were older than 16 years at diagnosis. Mutant IDH1 (R132H) protein immunohistochemistry was positive in 4 (of 22) (18%) cases, 3 of which also had 1p19q codeletion, whereas 1p19q status was not available on the fourth case. There was a nonsignificant trend for worse overall survival in grade III tumors, but no significant association with age, extent of resection, or 1p19q status. In summary, oligodendrogliomas with classic histology occur in the pediatric population but lack 1p19q codeletion and IDH1 (R132H) mutations in most instances. They are predominantly low grade, recur/clinically progress in a subset, but demonstrate a relatively low frequency of histologic progression.

Pediatric low-grade gliomas: how modern biology reshapes the clinical field

Low-grade gliomas represent the most frequent brain tumors arising during childhood. They are characterized by a broad and heterogeneous group of tumors that are currently classified by the WHO according to their morphological appearance. Here we review the clinical features of these tumors, current therapeutic strategies and the recent discovery of genomic alterations characteristic to these tumors. We further explore how these recent biological findings stand to transform the treatment for these tumors and impact the diagnostic criteria for pediatric low-grade gliomas.

Neurosurgical treatment of oligodendroglial tumors in children and adolescents: a single-institution series of 35 consecutive patients

OBJECT

The object of this study was to delineate long-term results of the surgical treatment of pediatric CNS tumors classified as oligodendroglioma (OD) or oligoastrocytoma (OA) WHO Grade II or III.

METHODS

A cohort of 45 consecutive patients 19 years or younger who had undergone primary resection of CNS tumors originally described as oligodendroglial during the years 1970-2009 at a single institution were reviewed in this retrospective study of surgical morbidity, mortality, and academic achievement and/or work participation. Gross motor function and activities of daily living were scored using the Barthel Index (BI).

RESULTS

Patient records for 35 consecutive children and adolescents who had undergone resection for an OA (17 patients) or OD (18 patients) were included in this study. Of the 35 patients, 12 were in the 1st decade of life at the first surgery, whereas 23 were in the 2nd decade. The male/female ratio was 1.19 (19/16). No patient was lost to follow-up. The tumor was localized to the supratentorial compartment in 33 patients, the posterior fossa in 1 patient, and the cervical medulla in 1 patient. Twenty-four tumors were considered to be WHO Grade II, and 11 were classified as WHO Grade III. Among these latter lesions were 2 tumors initially classified as WHO Grade II and later reclassified as WHO Grade III following repeat surgery. Fifty-four tumor resections were performed. Two patients underwent repeat tumor resection within 5 days of the initial procedure, after MRI confirmed residual tumor. Another 10 patients underwent a second resection because of clinical deterioration and progressive disease at time points ranging from 1 month to 10 years after the initial operation. Six patients underwent a third resection, and 1 patient underwent a fourth excision following tumor dissemination to the spinal canal. Sixteen (46%) of the 35 children received adjuvant therapy: 7, fractionated radiotherapy; 4, chemotherapy; and 5, both fractionated radiotherapy and chemotherapy. One patient with primary supratentorial disease experienced clinically malignant development with widespread intraspinal dissemination 9 years after initial treatment. Only 2 patients needed treatment for persistent hydrocephalus. In this series there was no surgical mortality, which was defined as death within 30 days of resection. However, 12 patients in the study, with follow-up times from 1 month to 33 years, died. Twenty-three patients, with follow-up times from 4 to 31 years, remained alive. Among these survivors, the BI was 100 (normal) in 22 patients and 80 in 1 patient. Nineteen patients had full- or part-time work or were in normal school programs.

CONCLUSIONS

Pediatric oligodendroglial tumors are mainly localized to the supratentorial compartment and more often occur in the 2nd decade of life rather than the 1st. Two-thirds of the patients remained alive after follow-ups from 4 to 31 years. Twelve children succumbed to their disease, 9 of them within 3 years of resection despite combined treatment with radio- and chemotherapy. Three of them remained alive from 9 to 33 years after primary resection. Among the 23 survivors, a stable, very long-term result was attainable in at least 20. Five-, 10-, 20-, and 30-year overall survival in patients with Grade II tumors was 92%, 92%, 92%, and 88%, respectively.

The use of 5-aminolevulinic acid fluorescence guidance in resection of pediatric brain tumors

INTRODUCTION

Whereas in the adult population 5-Aminolevulinic acid (5-ALA) fluorescence guidance has been widely accepted for improving the extent of tumor resection, the application in children remains an off-label use. Even though most pediatric study protocols require a complete resection for improving outcome parameters, only few pediatric patients have been operated with fluorescence guidance, and it remains questionable, whether and which pediatric tumors show useful fluorescence. We present casuistic reports of application of 5-ALA in children collected from three different neurosurgical departments.

PATIENTS AND METHODS

In children with suspected malignant intracerebral tumor or recurrence, individual informed consent was obtained in each case from the parents. 5-ALA was administered according to the adult protocol, with 20 mg/kg, 2 h before induction of anesthesia. We retrospectively analyzed 18 patients (13 male, 5 female; age 3-18 years), using the intraoperative neurosurgical protocol, the postoperative MRI results, and the follow-up clinical examinations.

RESULTS

The use of 5-ALA fluorescence guidance proved to be safe in our group of pediatric patients. Fluorescence guidance was most useful for recurrent glioblastoma resection. Medulloblastoma tissue displayed fluorescence only inconsistently, and most pilocytic astrocytoma remained without staining. Ganglioglioma showed partial staining in the central tumor areas, without allowing the use for circumferent resection.

CONCLUSION

The off-label use of 5-ALA fluorescence guidance in pediatric patients appears to be most useful in recurrent high-grade gliomas. Fluorescence accumulation in other pediatric brain tumor entities is not predictable and should be evaluated in future clinical studies before being integrated into the current treatment protocols.

Long-term follow-up of the multicenter, multidisciplinary treatment study HIT-LGG-1996 for low-grade glioma in children and adolescents of the German Speaking Society of Pediatric Oncology and Hematology

The Hirntumorstudien (HIT)-LGG-1996 protocol offered a comprehensive treatment strategy for pediatric patients with low-grade glioma (LGG), ie, observation, surgery, adjuvant radiotherapy, and chemotherapy to defer the start of irradiation in young children. In this current study, we sought to determine clinical factors for progression and survival. Between October 1, 1996 and March 31, 2004, 1031 patients were prospectively recruited into an observation arm (n = 668) and a nonsurgical arm stratifying 12 months of vincristine-carboplatin chemotherapy (n = 216) and conventional radiotherapy/brachytherapy (n = 147) in an age-dependent manner. Median patient age was 6.9 years; 28 patients had diencephalic syndrome, 44 had dissemination, and 108 had neurofibromatosis type 1(NF-1). Main tumor location was the supratentorial midline (40.4%), and the main histology was pilocytic astrocytoma (67.9%). Following a median observation of 9.3 years, 10-year overall survival (OS) was 0.94 and 10-year event-free survival (EFS) was 0.47. Ten-year progression-free survival was 0.62 following radiotherapy and 0.44 following chemotherapy. Sixty-one of 216 chemotherapy patients received radiotherapy 0.3-8.7 years after initial diagnosis. By multivariate analysis, diencephalic syndrome and incomplete resection were found to be unfavorable factors for OS and EFS, age ≥11 years for OS, and supratentorial midline location for EFS. Dissemination, age <1 year, and nonpilocytic histology were unfavorable factors for progression following radiotherapy (138 patients); and diencephalic syndrome, dissemination, and age ≥11 years were unfavorable factors following chemotherapy (210 patients). NF-1 patients and boys experienced prolonged tumor stabilization with chemotherapy. A nationwide multimodal treatment strategy is feasible for pediatric LGG. Extended follow-up yielded results comparable to single-institution series for the treatment groups. Three-quarters of surviving chemotherapy patients have not yet received radiation therapy. Infants with or without diencephalic syndrome and dissemination bear the highest risk for death and progression following diagnosis or treatment.

Impact of chemotherapy on disseminated low-grade glioma in children and adolescents: report from the HIT-LGG 1996 trial

BACKGROUND

We describe demographic data of disseminated childhood low-grade glioma (DLGG) prospectively recruited in the HIT-LGG 1996 study and evaluate the impact of primary chemotherapy (CT) on the outcome of these tumors, which have previously only been described in small and retrospective series.

PATIENTS AND METHODS

The multicenter study HIT-LGG 1996 accrued 1181 children and adolescents with low-grade glioma. 61 patients (5.2%) had tumor dissemination, with 2.8% being present at diagnosis. Frequencies of dissemination for different subgroups were calculated. Efficiency of first-line CT with vincristine/carboplatin was defined in 24 children with dissemination prior to first-line non-surgical-treatment.

RESULTS

Incidence of dissemination was high among infants (16%) with hypothalamic-chiasmatic-glioma (HCG) and diencephalic syndrome. A relevant percentage of HCG showed isolated spinal dissemination. CT achieved objective and overall response rates of 25% and 79% of the primary tumor and a similar response of disseminated lesions. Clinical stabilization or improvement could be achieved in the majority of patients during treatment. However, 20 of 24 patients experienced further progression and 5-year PFS was 6%. Dissemination prior to CT was a negative prognostic factor for PFS within the study (P = 0.005). Overall-survival of primary DLGG was inferior compared to LGG without dissemination at diagnosis (P < 0.001).

CONCLUSION

Complete MRI scan should be a standard diagnostic procedure in young children with hypothalamic-chiasmatic tumors especially if presenting with diencephalic syndrome. Dissemination in childhood LGG relates to impaired PFS. CT delays progression for responders. Multicenter studies have to evaluate the efficacy of extended treatment strategies in DLGG to improve outcome.

Incidence of gliomas by anatomic location

The anatomic location of a glioma influences prognosis and treatment options. The aim of our study was to describe the distribution of gliomas in different anatomic areas of the brain. A representative population-based sample of 331 adults with glioma was used for preliminary analyses. The anatomic locations for 89 patients from a single center were analyzed in more detail from radiologic imaging and recorded on a three-dimensional 1 x 1 x 1-cm grid. The age-standardized incidence rate of gliomas was 4.7 per 100,000 person-years. The most frequent subtypes were glioblastoma (47%) and grade II-III astrocytoma (23%), followed by oligodendroglioma and mixed glioma. The gliomas were located in the frontal lobe in 40% of the cases, temporal in 29%, parietal in 14%, and occipital lobe in 3%, with 14% in the deeper structures. The difference in distribution between lobes remained after adjustment for their tissue volume: the tumor:volume ratio was 4.5 for frontal, 4.8 for temporal, and 2.3 for parietal relative to the occipital lobe. The area with the densest occurrence was the anterior subcortical brain. Statistically significant spatial clustering was found in the three-dimensional analysis. No differences in location were found among glioblastoma, diffuse astrocytoma, and oligodendroglioma. Our results demonstrate considerable heterogeneity in the anatomic distribution of gliomas within the brain.

Thalamic gliomas in children: an extensive clinical, neuroradiological and pathological study of 14 cases

OBJECT

Thalamic tumors represent only 1 to 5% of brain neoplasms but frequently affect children. However, pediatric series are rare and go back to several years in spite of recent advances in the neuroradiological, pathological, and molecular fields.

METHODS

We report a series of 14 pediatric thalamic gliomas with clinical, neuroradiological, and pathological studies including p53 immunostaining in 11 cases and 1p19q status in three cases.

RESULTS

Our series included five pilocytic astrocytomas, seven oligodendrogliomas, and two glioblastomas. Pilocytic astrocytomas were characterized by strong contrast enhancement, lack of p53 expression, and excellent prognosis. Oligodendrogliomas frequently demonstrated an aspect of unilateral thalamic enlargement lacking or with slight contrast enhancement. Some of them expressed p53 or demonstrated 1p loss. Anaplastic oligodendrogliomas and glioblastomas displayed a poor outcome, with a mean survival of 8 months after surgery.

CONCLUSION

Our series of pediatric thalamic gliomas clearly distinguishes pilocytic astrocytomas from anaplastic oligodendrogliomas regarding neuroimaging, pathology, and prognosis.

Imaging surgical epilepsy in children

INTRODUCTION

Epilepsy surgery rests heavily upon magnetic resonance imaging (MRI). Technical developments have brought significantly improved efficacy of MR imaging in detecting and assessing surgical epileptogenic lesions, while more clinical experience has brought better definition of the pathological groups.

DISCUSSION

MRI is fairly efficient in identifying developmental, epilepsy-associated tumors such as ganglioglioma (with its variants gangliocytoma and desmoplastic infantile ganglioglioma), the complex, simple and nonspecific forms of dysembryoplastic neuroepithelial tumor, and the rare pleomorphic xanthoastrocytoma. The efficacy of MR imaging is not as good for the diagnosis of focal cortical dysplasia (FCD), as it does not necessarily correlate with histopathological FCD subtypes and does not show the real extent of the dysplasia which may even be missed in a high percentage of cases. Further developments with better, multichannel coils, higher magnetic fields, specific sequences, and different approaches (such as diffusion tensor imaging) for depicting the structural abnormalities may hopefully improve this efficacy. A general review of the MR features of the diverse pathologies concerned with epilepsy surgery in the pediatric context is provided with illustrative images.

From the archives of the AFIP: Oligodendroglioma and its variants: radiologic-pathologic correlation

Oligodendroglioma is the third most common glial neoplasm and most commonly arises in the frontal lobe. It occurs in males more frequently, and the peak manifestation is during the 5th and 6th decades. Children are affected much less commonly. The clinical presentation is often of several years duration with most patients presenting with seizures, reflecting the strong predilection of this tumor to involve the cortical gray matter. Current histopathologic classification schemes recognize two main types of tumors: well-differentiated oligodendroglioma and its anaplastic variant. Less commonly, neoplastic mixtures of both oligodendroglial and astrocytic components occur and are termed oligoastrocytomas, with both well-differentiated and anaplastic forms. Surgical resection is the mainstay of initial treatment, and many patients experience a long progression-free period. Recent genotyping has revealed chromosomal loss of 1p and 19q as a genetic signature in most oligodendrogliomas, and these tumors respond favorably to chemotherapy. Hence, radiation therapy is now generally reserved for partially resected tumors and cases that failed to benefit from chemotherapy. At cross-sectional imaging, the tumor characteristically involves the cortical gray matter and frequently contains calcification. Robust enhancement is not a common feature and suggests transformation to a higher histologic grade. Advanced magnetic resonance imaging techniques and metabolic imaging play increasingly important roles in both pre- and postoperative assessment of these complex neoplasms.

[MRI for oligodendrogliomas]

MRI has dramatically improved the management of cerebral tumors and consequently oligodendrogliomas. T1 and T2-weighted images and gadolinium enhancement are very useful for tumor detection and characterization. Tumor enhancement is of a great prognostic value because it is highly predictive of high-grade oligodendroglioma. Three-dimensional MR images provide, with high precision, the anatomical location and the relationships with functional structures (motor and language areas). The recent technical progress in MRI and the use of diffusion images in the screening of tumors lead to a better definition of the lesion. Comparative analysis of MRI images is helpful to detect eventual relapse and adverse effects of treatment.