Gliomatosis Cerebri: Current Understanding and Controversies

Digital "flipbooks" for enhanced visual assessment of simple and complex brain tumors

Typical longitudinal radiographic assessment of brain tumors relies on side-by-side qualitative visualization of serial magnetic resonance images (MRIs) aided by quantitative measurements of tumor size. However, when assessing slowly growing tumors and/or complex tumors, side-by-side visualization and quantification may be difficult or unreliable. Whole-brain, patient-specific "digital flipbooks" of longitudinal scans are a potential method to augment radiographic side-by-side reads in clinical settings by enhancing the visual perception of changes in tumor size, mass effect, and infiltration across multiple slices over time. In this approach, co-registered, consecutive MRI scans are displayed in a slide deck, where one slide displays multiple brain slices of a single timepoint in an array (eg, 3 × 5 "mosaic" view of slices). The flipbooks are viewed similarly to an animated flipbook of cartoons/photos so that subtle radiographic changes are visualized via perceived motion when scrolling through the slides. Importantly, flipbooks can be created easily with free, open-source software. This article describes the step-by-step methodology for creating flipbooks and discusses clinical scenarios for which flipbooks are particularly useful. Example flipbooks are provided in Supplementary Material.

Revisiting prognostic factors of gliomatosis cerebri in adult-type diffuse gliomas

PURPOSE

There is lack of comprehensive analysis evaluating the impact of clinical, molecular, imaging, and surgical data on survival of patients with gliomatosis cerebri (GC). This study aimed to investigate prognostic factors of GC in adult-type diffuse glioma patients.

METHODS

Retrospective chart and imaging review was performed in 99 GC patients from adult-type diffuse glioma (among 1,211 patients; 6 oligodendroglioma, 16 IDH-mutant astrocytoma, and 77 IDH-wildtype glioblastoma) from a single institution between 2005 and 2021. Predictors of overall survival (OS) of entire patients and IDH-wildtype glioblastoma patients were determined.

RESULTS

The median OS was 16.7 months (95% confidence interval [CI] 14.2-22.2) in entire patients and 14.3 months (95% CI 12.2-61.9) in IDH-wildtype glioblastoma patients. In entire patients, KPS (hazard ratio [HR] = 0.98, P = 0.004), no 1p/19q codeletion (HR = 10.75, P = 0.019), MGMTp methylation (HR = 0.54, P = 0.028), and hemorrhage (HR = 3.45, P = 0.001) were independent prognostic factors on multivariable analysis. In IDH-wildtype glioblastoma patients, KPS (HR = 2.24, P = 0.075) was the only independent prognostic factor on multivariable analysis. In subgroup of IDH-wildtype glioblastoma with CE tumors, total resection of CE tumor did not remain as a significant prognostic factor (HR = 1.13, P = 0.685).

CONCLUSIONS

The prognosis of GC patients is determined by its underlying molecular type and patient performance status. Compared with diffuse glioma without GC, aggressive surgery of CE tumor in GC patients does not improve survival.

Clinical and imaging features of lymphomatosis cerebri: analysis of 8 cases and systematic review of the literature

Lymphomatosis cerebri (LC) is a rare type of primary central nervous system lymphoma with diffuse, nonenhancing infiltrative lesions and is often misdiagnosed. Our study aimed to investigate the clinical characteristics and prognosis of LC through analyzing patients from the literature and our own center, so as to improve early diagnosis and treatment. PubMed, Web of Science and our hospital databases were reviewed, and information on demographic, clinical, pathological, cerebrospinal fluid (CSF), neuroimaging and treatment options was extracted. Univariate survival analysis was conducted by generating survival curves and comparing them using the log-rank test. Multivariate analysis was performed using the Cox proportional hazards regression model to identify the prognostic predictors. A total of 81 patients (median age: 58 years; interquartile range, IQR: 50-66.5 years), 45 males and 36 females, were included. The most common symptoms were cognitive impairment (65.4%) and gait impairment (50.6%). Imaging studies indicated that all 81 patients had supratentorial structure involvement, and 93.8% (76/81) had bilateral hemisphere involvement. There were 53.3% (32/60) patients with CSF pleocytosis and 65% (39/60) patients with increased CSF protein levels. The median time of diagnosis was 4.8 months (IQR: 2.3-6.9 months). Compared with 4 (95% CI: 1.78-6.22) months for all 81 patients, the median OS was 20 (95% CI: 8.24-31.76) months for those who had chemotherapy plus radiotherapy. Multivariate Cox analysis revealed that chemoradiotherapy (HR: 0.12; 95% CI: 0.02-0.68) and higher CSF glucose level (HR: 0.01; 95% CI: 0.00-0.26) were inversely associated with death. The diagnosis of LC should be alerted when neuroimaging with bilateral hemispheric involvement and CSF abnormality with pleocytosis and increased protein. Once the diagnosis is confirmed, the combination of chemotherapy and radiotherapy can be considered if the patient's physical condition permits.Journal standard instruction requires an unstructured abstract. Kindly check and confirm.We have checked and confirmed that there is no problem.

Naturopathic Treatment of Grade III Oligodendroglioma With Progression to Grade IV Isocitrate Dehydrogenase (IDH)-Mutant Astrocytoma and the Development of Spinal Gliomatosis

Primary intracranial gliomas are a heterogeneous class of lesions that rarely metastasize. Even more infrequently, they may spread caudally into the spinal cord causing spinal gliomatosis. In this case, we discuss an 18-year-old male patient with a diagnosis of grade IV astrocytoma with spinal gliomatosis, specifically detailing the radiographic progression of the disease over 38 months. We also discuss the significance of the change in the WHO classification of central nervous system tumors, as this patient's survival duration is inconsistent with the low survival rates expected of glioblastoma, and rather more consistent with a grade IV astrocytoma.

Gliomatosis cerebri with blindness: A case report with literature review

Cerebral gliomatosis (GC) is a rare diffuse infiltrative growth pattern of glioma with nonspecific clinical manifestations like visual impairment that may involve bilateral temporal lobes. Herpes simplex encephalitis (HSE) and limbic encephalitis (LE) can also lead to temporal lobe involvement. Differentiating these entities is necessary for patients with misleading presentations and imaging findings. To the best of our knowledge, this is the third case of GC presenting with blindness. The patient was a 35 years-old male in a drug rehabilitation center for heroin addiction. He presented with a headache, a single episode of seizure, and a 2-month history of bilateral decrease in visual acuity, which had acutely worsened. Magnetic resonance imaging (MRI) and computed tomography (CT) showed bilateral temporal lobe involvement. Ophthalmological studies showed bilateral papilledema, absence of visual evoked potential, and thickening of the retinal nerve fiber layer. Due to this clinical presentation, normal laboratory data, and suspicious MRI findings, further investigation with magnetic resonance spectroscopy (MRS) was performed. Results showed a greatly increased ratio of choline to creatinine(Cr) or N-acetyl aspartate (NAA), suggesting a neoplastic nature of the disease. Subsequently, the patient was referred for a brain tissue biopsy with a suspicion of malignancy. The pathology results revealed adult-type diffuse glioma with isocitrate dehydrogenase (IDH) mutation. Bilateral blindness, as well as bilateral temporal lobe involvement, each has many different causes. However, as demonstrated in this study, adult-type diffuse glioma must be considered a rare cause of concomitant bilateral temporal lobe involvement and blindness.

An enduring debate on gliomatosis cerebri

Gliomatosis cerebri (GC) is a unique glial tumor that extensively invades the cerebral white matter and has been recognized as an entity of neuroepithelial tumors since the first edition of the WHO classification of brain tumors in 1979. Thereafter, in the fourth edition of the WHO classification in 2007, it was clearly defined as a specific type of astrocytic tumor. However, in the WHO 2016 classification, which was based on the concept of integrated diagnosis using molecular genetics, GC was deleted as it was considered to be only one growth pattern of diffuse glioma and not a specific pathological entity. Since then, there has been criticism by many neuro-oncologists and the establishment of the GC working group at the NIH, and many activities in the world arguing that GC should not be deleted from the clinical discussion of brain tumors. In Japan, positive activities toward multicenter research on GC pathology should be performed, and molecular pathological evidence that can contribute to the WHO classification in the future should be developed. In this article, the author outlined the pathological characteristics of GC, which has been repeated changing since its conception, and also describes his opinion on GC as a neuro-oncologist.

Clinical, Imaging and Neurogenetic Features of Patients with Gliomatosis Cerebri Referred to a Tertiary Neuro-Oncology Centre

INTRODUCTION

Gliomatosis cerebri describes a rare growth pattern of diffusely infiltrating glioma. The treatment options are limited and clinical outcomes remain poor. To characterise this population of patients, we examined referrals to a specialist brain tumour centre.

METHODS

We analysed demographic data, presenting symptoms, imaging, histology and genetics, and survival in individuals referred to a multidisciplinary team meeting over a 10-year period.

RESULTS

In total, 29 patients fulfilled the inclusion criteria with a median age of 64 years. The most common presenting symptoms were neuropsychiatric (31%), seizure (24%) or headache (21%). Of 20 patients with molecular data, 15 had IDH wild-type glioblastoma, with an IDH1 mutation most common in the remainder (5/20). The median length of survival from MDT referral to death was 48 weeks (IQR 23 to 70 weeks). Contrast enhancement patterns varied between and within tumours. In eight patients who had DSC perfusion studies, five (63%) had a measurable region of increased tumour perfusion with rCBV values ranging from 2.8 to 5.7. A minority of patients underwent MR spectroscopy with 2/3 (66.6%) false-negative results.

CONCLUSIONS

Gliomatosis imaging, histological and genetic findings are heterogeneous. Advanced imaging, including MR perfusion, could identify biopsy targets. Negative MR spectroscopy does not exclude the diagnosis of glioma.

Cranial Spinal Spreading of Canine Brain Gliomas after Hypofractionated Volumetric-Modulated Arc Radiotherapy and Concomitant Temozolomide Chemotherapy: A Four-Case Report

Gliomas are the second-most-common primary brain tumors in dogs. Surgery and radiotherapy are established treatment approaches with similar median survival time, whereas conventional chemotherapy is burdened by severe adverse effects. Spinal and leptomeningeal spread of gliomas have been described following radiotherapy treatment alone. The purpose of this study was to evaluate the outcome for four dogs with primary high-grade gliomas in the forebrain without evidence, at diagnosis, of neoplastic invasion along the spinal cord, that were treated with concomitant chemotherapy (temozolomide) and hypofractionated volumetric-modulated arc radiotherapy (VMAT-RT). Temozolomide was selected for its radiosensitive properties, and radiotherapy dose protocols of 37 Gy in 7 fractions or 42 Gy in 10 fractions were used. After an initial complete or partial response, tumors recurred across the cranial-spinal pathway. Post-mortem macroscopic examinations confirmed swollen spinal cord and hyperemic meningeal sleeve, with nodular lesions on the meningeal surface. Microscopically, infiltration of the spinal cord and meninges by neoplastic cells (with features of oligodendrogliomas) were observed. This work seems to suggest that the entire central nervous system should be investigated in diagnostic examinations of canine gliomas. Dose-escalation trials and/or spinal cord prophylaxis treatment could also be evaluated to prevent tumor progression.

Surgical treatment of diffuse and multi-lobes involved glioma with the assistance of a multimodal technique

Diffuse and multi-lobes involved glioma (DMG) is a rare disease, and the aim of this study was to assess the role of multimodal-assisted surgical resection of tumours combined with chemoradiotherapy and identify prognosis. Clinical data were collected from 38 patients with a diagnosis of DMG. Nineteen patients received multimodal-assisted surgical resection of tumours combined with chemoradiotherapy, and another 19 patients underwent chemoradiotherapy alone after stereotactic puncture biopsy. The clinical characteristics, magnetic resonance imaging (MRI) findings, histopathological diagnosis, progression-free survival, and overall survival of DMG patients were retrospectively analysed. Twenty-six males and 12 females were included, and the age of the participants ranged from 10 to 80 years (46.34 ± 15.61). The median overall survival in our study was 25 months, and the progression-free survival was 17 months. The extent of resection was 50.10–73.60% (62.54% ± 7.92%). The preoperative and the postoperative KPS score of the patients in the operation group showed no statistically significant difference. The results of logistic regression demonstrated that overall survival was positively associated with operative treatment + chemoradiotherapy (p = 0.003) but negatively associated with age and corpus callosal involvement (p = 0.028 and 0.022, respectively). Kaplan–Meier analyses showed that those who underwent surgical treatment had a significant progression-free and overall survival benefit compared to those who did not undergo surgical treatment (log-rank test; p = 0.011 and 0.008, respectively). Older age and involvement of the corpus callosum represent a poor prognosis in DMG patients. Multimodal-assisted surgical resection of tumours combined with chemoradiotherapy might be a treatment option for DMG. Further research is needed to obtain the clear evidence of the effect of surgical treatment.

PET findings in lymphomatosis and gliomatosis of the brain: a comparison of C-11 methionine PET/CT and F-18 FDG PET/CT

BACKGROUND

Positron emission tomography (PET) findings for gliomatosis and lymphomatosis have been rarely reported.

PURPOSE

To compare PET/computed tomography (CT) findings using ¹¹C-methionine (MET) from PET/CT findings using ¹⁸F-fluorodeoxy glucose (FDG) for patients with lymphomatosis or gliomatosis of the brain.

MATERIAL AND METHODS

Participants comprised all 10 patients with lymphomatosis or gliomatosis of the brain treated at our institution in the past 12 years. Underlying pathologies comprised intravascular lymphoma (n = 1), lymphomatosis (n = 3), and gliomatosis (n = 6). All cases were pathologically diagnosed. In seven patients, both MET-PET/CT and FDG-PET/CT were performed simultaneously in a single study. In three patients, only FDG-PET/CT was performed. The degree of tracer accumulation to the lesion was evaluated qualitatively. Quantitatively, the ratio of maximum standard uptake value (SUV_max) in tumor to that in normal tissue (T/N ratio) was measured and compared between FDG and MET.

RESULTS

Qualitatively, MET accumulated to part of the lesion in six of seven patients and almost all of the lesion in one in seven patients. FDG accumulated to part of the lesion in three of ten patients and almost all of the lesion in one of ten patients. No FDG accumulation was seen in the lesion in six patients. Quantitatively, mean ± SD T/N ratio was significantly higher with MET (2.11 ± 0.63) than with FDG (1.18 ± 0.84; P < 0.05, Wilcoxon signed-rank test).

CONCLUSION

In lymphomatosis and gliomatosis, FDG accumulates in only part of the lesion. FDG is thus less suitable than MET for depicting these lesions.

Leptomeningeal dissemination of anaplastic medullary cone astrocytoma: an unexpected findings in a patient with leptomeningeal enhancement and clinical history of multiple myeloma

We report a challenging autopsy case with an insidious clinical presentation with diffuse lepto- and pachymeningeal enhancement in a context of a complex clinical history. Clinical features, neuroradiological and anamnestic data were consistent with central nervous system (CNS) dissemination of a previously known lambda restricted multiple myeloma. Autoptic findings allowed to discard this hypothesis. Unexpectedly, CNS sampling revealed an atypical glial cell proliferation within the sacral meningeal layers. No primary intraparenchymal CNS glial lesion was found. Findings supported the final diagnosis of anaplastic astrocytoma IDH1-wild type of the medullary cone with diffuse leptomeningeal and cerebrospinal fluid (CSF) dissemination. This occurrence represents an extremely rare condition itself, further complicated by the clinical history of the patient that led to formulate the most probable diagnosis of localization of the primary known disease. This autopsy case underlines that patients previously diagnosed with a primary tumor are not only at risk of recurrences or progression of the original disease, but they must be always accurately checked for eventual onset of a second tumor, including rare conditions such as gliomatosis.

A rare case of gliomatosis cerebri lurking beneath the shadows of a stroke mimic

Gliomatosis cerebri (GC) is a diffuse infiltrative neoplastic glial process with a devastating prognosis. Considering its rarity, unpredictable clinical manifestations, and lack of characteristic radiographic features, GC is a difficult diagnosis that is quite often delayed. In this report, we present a case of a 61-year-old man with a history of chronic alcohol abuse and atrial fibrillation who presented with right arm weakness initially presumed to be from an acute ischemic stroke. GC was not diagnosed until six months after initial symptoms and diagnosis was indicated when considering the neurocognitive findings in conjunction with suggestive radiographic findings. The presence of a rapid, expansile lesion in the cortex, corpus callosum, and infratentorial structures with mild parenchymal enlargement, as shown in our case, is more revealing of an invasive entity typical of GC rather than an ischemic process and other pathologies. This case demonstrates the fatal challenges of its prompt recognition and the therapeutic limitations for those patients presenting with advanced symptoms at the time of diagnosis. Recognizing GC in cases with such rapid multilobe clinical features with similar diffusely invasive patterns of growth on imaging can avoid a delay in diagnosis and improve patient quality of life.

Aberrant Rac pathway signalling in glioblastoma

Glioblastoma is an aggressive and incurable form of brain cancer. Both mutation analysis in human glioblastoma and mouse modelling studies have shown that aberrant activation of the PI 3-kinase pathway is a central driver of glioblastoma malignancy. The small GTPase Rac is activated downstream of this pathway, mediating a subset of the effects of aberrant PI 3-kinase pathway activation. Here I discuss the current state of our knowledge on Rac activation mechanisms in glioblastoma. Current knowledge on roles for specific PI 3-kinase pathway responsive Rac guanine nucleotide exchange factors in glioblastoma is reviewed. Rac is best known for its role in promoting cell motility and invasion, but there is also evidence for roles in multiple other cellular processes with cancer relevance, including proliferation, differentiation, apoptosis, DNA damage responses, metabolism, angiogenesis and immunosuppression. I review what is known about the role of Rac in these processes in glioblastoma. Finally, I assess possible strategies to inhibit this pathway in glioblastoma through either direct inhibition of Rac or inhibition of upstream activators or downstream mediators of Rac signalling.

Fluctuation of Clinical Signs With Near-Syncopal Episodes in a Dog With Gliomatosis Cerebri: A Diagnostic Challenge

A 2-year-old Bull Mastiff cross Boxer neutered male dog was evaluated because of 2-month history of non-progressive right head tilt and mild vestibular ataxia. MRI of the brain revealed a faint T2W, FLAIR, DWI and ADC heterogenous hyperintense and T1W isointense intra-axial lesion with indistinct margins at the level of the pons and medulla oblongata. The lesion did not show any susceptibility artefact on T2* GRE images or contrast enhancement and CSF analysis was normal. Analysis of the spectra from MRS of the thalamus not promptly available at the time of the MRI study revealed a decreased level of NAA, as seen in people with gliomatosis cerebri. The dog represented 3 weeks later and, on this occasion, displayed left-sided head tilt, left-sided postural reaction deficits and near-syncopal episodes associated with state of confusion. Repeated MRI revealed a larger non-enhancing intra-axial lesion with a more hyperintense signal than previously described. CSF was normal and PCR of CSF for infectious diseases was negative. Thoracic and abdominal computed tomography did not reveal any primary or metastatic process. Immunosuppressive treatment was attempted and the dog remained stable over 5 days, then developed generalized tonic-clonic seizures which led to status epilepticus and death. Histopathology supported the diagnosis of gliomatosis cerebri. Gliomatosis cerebri remains difficult to diagnose ante-mortem, due to the broad age of onset and the variable duration and wide range of clinical signs. The mismatch between MRI findings and clinical presentation, the fluctuating clinical signs with near-syncopal episodes associated with a state of confusion, the presence of an infiltrative brain disease as depicted on MR imaging and a normal CSF analysis, should prompt the clinician to consider possible diagnosis of a widespread infiltrative neoplasm. Although, MRS may help narrow the differential diagnosis in favor of a neoplastic lesion, the overall prognosis remains poor.

Canine Gliomatosis Cerebri: Morphologic and Immunohistochemical Characterization Is Supportive of Glial Histogenesis

Gliomatosis cerebri (GC) is a glioma subtype with diffuse neuroparenchymal infiltration without architectural distortion. GC was first used in human neuropathology and remained controversial until its elimination from the diagnostic lexicon in 2016. GC is currently defined as a diffuse growth pattern of glioma rather than a distinct entity. In this article, we characterize 24 cases of canine GC and classify these neoplasms as diffuse gliomas. Selected cases of canine GC were reviewed and immunolabeled for oligodendrocyte lineage transcription factor 2 (Olig2), glial fibrillary acidic protein (GFAP), and 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase). The mean age of affected dogs was 7 years, and 9 were brachycephalic. Gross lesions (8 cases) consisted mainly of parenchymal swelling. Histologically, of the 24 cases, there was widespread infiltration of neoplastic cells with astrocytic (12 cases), oligodendroglial (8 cases), or mixed morphology (4 cases) in the brain (18 cases), spinal cord (4 cases), or both (2 cases). Secondary structures occurred across different tumor grades and were not restricted to high-grade neoplasms. Astrocytic neoplasms had moderate nuclear immunolabeling for Olig2 and robust cytoplasmic immunolabeling for GFAP. Oligodendroglial neoplasms had robust nuclear immunolabeling for Olig2, moderate or absent cytoplasmic immunolabeling for GFAP, and moderate cytoplasmic immunolabeling for CNPase. Tumors with mixed morphology had robust nuclear immunolabeling for Olig2 and variable cytoplasmic immunolabeling for GFAP and CNPase. Morphologic and immunohistochemical features confirmed a glial histogenesis for all tumors and allowed for their classification as diffuse, low- or high-grade astrocytoma; oligodendroglioma; or undefined glioma. Further research is needed to confirm or refute the hypothesis that canine GC represents an infiltrative growth pattern of canine glioma.

Predictive factors for overall survival in surgical cases of gliomatosis cerebri from the National Cancer Database

Gliomatosis Cerebri (GC) is a rare, aggressive, diffusely infiltrating cerebral tumor. Prognostic indicators and management strategies are currently poorly characterized. The National Cancer Database was queried for patients with histologically confirmed GC between 2004 and 2016. Demographic, tumor, and treatment characteristics were collected, including the Charlson/Deyo score, a comorbidity index adapted from the Charleston Comorbidity Index. Allowable values for the Charlson/Deyo score are 0 (no recorded comorbidities), 1, 2, and 3+ (most severe). Factors associated with overall survival were identified via bivariate log-rank tests and multivariate stepwise Cox proportional hazards models. The query returned 108 GC patients. The median age was 60.0 years, males were predominantly affected (63%), and most patients were white (86%). While 12% of cases achieved near/gross total resection and 27% of cases achieved partial resection, most surgeries were for biopsy (61%). Treatments included radiation therapy in 64% and chemotherapy in 63% of patients. The median overall survival was 15.1 (95% confidence interval [CI] = 11.1-24.8) months. On bivariate analysis, chemotherapy improved overall survival (p = 0.01) while radiation therapy (p = 0.07) and extent of resection (p = 0.48) did not. On multivariate analysis, older patients (hazard ratio [HR] = 1.07, CI = 1.03-1.11, p < 0.01) and Charlson/Deyo scores of ≥1 versus 0 (HR = 3.47, CI = 1.40-8.60, p < 0.01) had significantly increased mortality risk following surgery. In particular, the Charlson/Deyo score is a novel prognostic factor for GC that may guide clinical and surgical decision-making for this rare, rapidly fatal tumor. Further prospective studies are warranted to clarify the effects of chemotherapy versus radiation as treatment modalities for GC.

Gliomatosis cerebri (GC) or GC-like? A picture to be reconsidered in neuro-oncology based on large retrospective analysis of GC series

INTRODUCTION

Gliomatosis cerebri (GC), defined until 2016 as a distinct astrocytic glioma entity, has been removed from the 2016 World Health Organization classification of tumors of the central nervous system. However, its identity is still debated.

MATERIALS AND METHODS

We retrospectively present 122 patients, including a subgroup with histology confirmation (n = 75, cohort b).

RESULTS

Radiological features showed extension limited to 3 lobes in 31%; bilateral, midline, and basal ganglia and subtentorial involvement in 95%, 52%, 84%, and 60%, respectively; and contrast enhancement in 59.5%. Perioperative mortality occurred in 4%. Histology concluded for grades II, III, and IV, respectively, in 31%, 35%, and 22% (not specified in 12%). Thirty-one percent had isocitrate dehydrogenase (IDH) 1 mutation. Treatments included radiotherapy in 51.2% and chemotherapy in 74.5%. Median overall survival was 17 months. Negative prognostic factors for survival were older age, poorer Karnofsky Performance Scale (KPS), subtentorial, midline and disseminated disease, and lack of chemotherapy, at univariate analysis. At multivariate analysis, KPS ≥ 80, chemotherapy, and subtentorial and disseminated disease remained prognostic (p < 0.0001). For cohort b, same prognostic factors were confirmed, except for midline location, at univariate analysis; at multivariate analysis, only KPS ≥ 80 and chemotherapy remained prognostic (p < 0.0001).

CONCLUSION

We described clinical, neuroimaging, management, and histomolecular features of one of the largest GC series. We identified KPS ≥ 80, radiological pattern as subtentorial localization and dissemination, and chemotherapy as prognostic factors, at multivariate analysis. Planning prospective study, associated to focused genetic assays, could help to clarify if GC has specific features that may result in the identification as a separate entity from other gliomas.

Clinical relevance of molecular subgrouping of gliomatosis cerebri per 2016 WHO classification: a clinicopathological study of 89 cases

The extremely invasive phenotypes and genotypes related to progression of gliomatosis cerebri (GC) remain unclear although GC has been removed as an independent entity from the 2016 WHO classification. Hence, categorization of GC under the current WHO molecular classification is essential, and the molecular subgroups that might contribute to GC progression should be compared with the histopathological differences between initial and new lesions identified during follow-up. Analyses of IDH1/2 and TERTp mutations and 1p/19q co-deletion, and immunohistochemistry of IDH1-R132H, ATRX, p53 and galectin-3 were performed. Anaplastic astrocytoma, IDH-wildtype (AA-IDHwt) was the common molecular subgroup (52.8%), followed by diffuse astrocytoma, IDH-wildtype (DA-IDHwt) and AA, IDH-mutant (AA-IDHmt) (each 16.9%), DA-IDHmt (7.9%), glioblastoma (GBM)-IDHwt (3.3%) and GBM-IDHmt (2.2%). Approximately 92% of the AA-IDHwt lesions progressed to histologically confirmed GBM in the newly enhanced lesions harboring the TERTp mutation and expressing galectin-3. Similar to primary GBMs, GC-related GBMs that progressed from the IDHwt subgroups showed microvascular proliferation, palisading necrosis or thrombotic occlusion, implying that a subset of IDHwt subgroups may evolve to overt GBM. Molecular subgrouping did not provide the perfect prediction for the survival of GC patients. The AA-IDHwt group showed worse overall and progression-free survival (PFS) than the AA-IDHmt group. Biopsy plus radiotherapy, chemotherapy and temozolomide treatment for DA-IDHwt, and resection plus radiotherapy and temozolomide treatment for AA-IDHwt prolonged PFS. In conclusions, majority of GC was of the AA-IDHwt subgroup, which progressed to GBM. Molecular subgroups may assist in the selection of treatment modalities, because "GC pattern" still remains as a special growth of gliomas in WHO 2016 classification without established treatment guideline.

Gliomatosis Cerebri: A Unique Presentation with Accompanying Clinical Nuance

Gliomatosis cerebri (GC) has classically been considered a rare malignancy with a poor prognosis and is developmentally unique from solid tumors. More recently, GC has become better understood as a phenotype along the spectrum of gliomas and, most importantly, not mutually exclusive from the more common presentation of a tumor mass. The following case report illustrates not only the implications of the ontogeny of gliomas in clinical practice but also the successes that can accompany the early recognition of such a disease. Here, we report the presentation of a solid temporal lobe glioma, which, on presentation, was disseminating along well-defined mesolimbic white matter tracts. Once properly diagnosed and managed, the patient remarkably proceeded to achieve an impressive outcome given the extent of her pathology.

Gliomatosis Cerebri Among Children and Adolescents: An Individual-Patient Data Meta-analysis of 182 Patients

BACKGROUND

Gliomatosis cerebri is a rare but fatal widespread infiltrating central nervous system tumor. We aimed to describe diagnostic and prognostic features of gliomatosis cerebri among children and adolescents.

METHODS

We conducted a systematic literature review for published case reports and case series on patients with histologically confirmed gliomatosis cerebri and extracted data on an individual patient level for those aged 0-18 years. Multivariable Cox proportional hazard models were fit for overall survival.

RESULTS

Following screening of 274 published studies, 182 gliomatosis cerebri patients (63% males) aged 0-18 years with individual-level data available were identified. The most common presenting symptoms were seizures (52%), focal motor deficits (36%), and headache (30%). Imaging showed bilateral hemisphere involvement in 60%, infratentorial infiltration in 39%, and a focal contrast-enhanced mass (type II gliomatosis cerebri) in 27% of cases. Anaplastic astrocytoma was the most common histologic subtype of pediatric gliomatosis cerebri, whereas MGMT promoter methylation, IDH1 mutations, and codeletion of 1p/19q were less common molecular aberrations, as compared to adult gliomatosis cerebri. In the multivariable analyses, age at diagnosis >4 years, extended central nervous system infiltration, coordination abnormalities, and cognitive decline were predictors of worse outcome. Conversely, IDH1 mutations were associated with prolonged overall survival. Chemotherapy and extended surgical resection were associated with improved outcome, whereas radiotherapy was not associated with overall survival and was inferior to chemotherapy alone.

CONCLUSION

Gliomatosis cerebri among children and adolescents presents distinct histopathologic and molecular features compared to adults. However, similar associations of chemotherapy, and, when feasible, extended surgical resection, with favorable outcomes were noted among the 2 age groups.

Gliomatosis cerebri: a consensus summary report from the Second International Gliomatosis cerebri Group Meeting, June 22-23, 2017, Bethesda, USA

Gliomatosis cerebri (GC) is an aggressive glioma characterized by an invasive growth pattern and a dismal prognosis. The low incidence and non-specific symptoms at presentation pose unique challenges for early diagnosis and disease-specific research. There is no standard of care for the treatment of patients with a GC phenotype. Understanding the biology of this entity is a critical step in determining effective treatments. Toward this end, the Second International GC Group convened at National Institutes of Health, Bethesda on June 22nd-23rd 2017. This paper summarizes the main conclusions and recommendations for research priorities to fight this fatal condition.

Incidence and survival of gliomatosis cerebri: a population-based cancer registration study

Gliomatosis cerebri (GC) comprises a rare widespread infiltrating growth pattern of diffuse gliomas. We explored the incidence patterns and survival rates of GC in a population-based registration sample from the Surveillance, Epidemiology and End, Results database (1973-2012). GC cases (n = 176) were identified based on their International Classification of Diseases in Oncology (ICD-O-3) morphology code (9381). We calculated age-adjusted incidence rates (AIR) and evaluated temporal trends. Survival was assessed with Kaplan-Meier curves and Cox regression models. The annual AIR of GC was 0.1/million. We noted increasing trends in the preceding registration years (1973-2002; annually, + 7%) and a tendency of clinical/radiological approaches to substitute the gold-standard histological assessment for diagnosis. GC was diagnosed in the entire age spectrum (range 1-98 years), but higher incidence rates (0.43/million) were noted among the elderly (≥ 65 years). A slight male preponderance was identified (male-to-female ratio: 1.4). Median overall survival was 9 months with a 5 year survival rate of 18%. Increasing age, primary tumor location not restricted to the cerebral hemispheres and rural residence at diagnosis were identified as negative prognostic factors, whereas receipt of radiotherapy, surgical treatment, race and method of diagnosis were not associated with outcome. This first comprehensive overview of GC epidemiology exemplifies the rarity of the disease, provides evidence for male preponderance and increased incidence among the elderly and shows lower survival rates compared to the published single center reports. Expansion of registration to histological and molecular characteristics would allow emergence of clinical prognostic factors at the population level.