Drug-resistant high grade glioma-related epilepsy surgery for focal motor status epilepticus localized by CT-PET imaging.

Tumor-related epilepsy is a frequent complication of glioblastoma with seizures often representing the first manifestation of the malignancy. Though tumor resection is associated with improved seizure control, extensive surgery is not always feasible if eloquent cortex is involved in seizure generation and early propagation. We describe a case of a patient with glioblastoma with drug-resistant focal status epilepticus where fluorodeoxyglucose positron emission tomography imaging was successfully used to localize the seizure-onset and optimize tumor resection. This led to successful resection of hypermetabolic tumor tissue and resolution of focal status epilepticus without damage to eloquent cortex.

Histone-mutant glioma presenting as diffuse leptomeningeal disease.

Glioblastoma multiforme is the most common malignant primary brain tumor in adults. Histone H3 mutations have been identified in pediatric and adult gliomas, with H3K27M mutations typically associated with a posterior fossa midline tumor location and poor prognosis. Leptomeningeal disease is a known complication of histone-mutant glioma, but uncommon at the time of initial diagnosis. We describe a case of glioblastoma with H3K27M mutation that initially presented with progressive vision loss due to diffuse leptomeningeal disease in the absence of a mass lesion other than a small cerebellar area of enhancement and with cerebrospinal fluid cytology negative for malignant cells on two occasions, highlighting the importance of including primary CNS malignancies in the differential of diffuse radiographic leptomeningeal enhancement.

Lay abstract Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor in adults. Histones are molecules around which DNA winds. GBM and other gliomas sometimes have genetic alterations called mutations in histone genes. Of these, a specific alteration in histone 3 called H3K27M has been described in a variety of primary brain tumors. In adult gliomas, the H3K27M mutation is typically associated with tumors located within the brainstem or other structures in the midline of the central nervous system and a poor prognosis. Although previously reported, involvement of the leptomeninges (the thin membranes covering the brain and spinal cord) is uncommon at the time of initial diagnosis of gliomas harboring H3K27M mutations. We describe a case of GBM that initially presented with vision loss due to diffuse leptomeningeal involvement. Imaging and laboratory studies, including two cerebrospinal fluid analyses by lumbar puncture, did not establish a diagnosis. Brain biopsy confirmed the presence of a tumor, and genetic testing performed on the tumor tissue identified the histone mutation. This case highlights the importance of including primary central nervous system malignancies as a possible diagnosis when there is diffuse radiographic leptomeningeal enhancement.

Functional connectivity changes in the language network during stroke recovery.

OBJECTIVE: Several neuroimaging studies have examined language reorganization in stroke patients with aphasia. However, few studies have examined language reorganization in stroke patients without aphasia. Here, we investigated functional connectivity (FC) changes after stroke in the language network using resting-state fMRI and performance on a verbal fluency (VF) task in patients without clinically documented language deficits. METHODS: Early-stage ischemic stroke patients (N = 26) (average 5 days from onset), 14 of whom were tested at a later stage (average 4.5 months from onset), 26 age-matched healthy control subjects (HCs), and 12 patients with cerebrovascular risk factors (patients at risk, PR) participated in this study. We examined FC of the language network with 23 seed regions based on a previous study. We evaluated patients' behavioral performance on a VF task and correlation between brain resting-state FC (rsFC) and behavior. RESULTS: Compared to HCs, early stroke patients showed significantly decreased rsFC in the language network but no difference with respect to PR. Early stroke patients showed significant differences in performance on the VF task compared to HCs but not PR. Late-stage patients compared to HCs and PR showed no differences in brain rsFC in the language network and significantly stronger connections compared to early-stage patients. Behavioral differences persisted in the late stage compared to HCs. Change in specific connection strengths correlated with changes in behavior from early to late stage. CONCLUSIONS: These results show decreased rsFC in the language network and verbal fluency deficits in early stroke patients without clinically documented language deficits.

Usage of fMRI for pre-surgical planning in brain tumor and vascular lesion patients: task and statistical threshold effects on language lateralization.

BACKGROUND AND PURPOSE: Functional magnetic resonance imaging (fMRI) is a non-invasive pre-surgical tool used to assess localization and lateralization of language function in brain tumor and vascular lesion patients in order to guide neurosurgeons as they devise a surgical approach to treat these lesions. We investigated the effect of varying the statistical thresholds as well as the type of language tasks on functional activation patterns and language lateralization. We hypothesized that language lateralization indices (LIs) would be threshold- and task-dependent. MATERIALS AND METHODS: Imaging data were collected from brain tumor patients (n = 67, average age 48 years) and vascular lesion patients (n = 25, average age 43 years) who received pre-operative fMRI scanning. Both patient groups performed expressive (antonym and/or letter-word generation) and receptive (tumor patients performed text-reading; vascular lesion patients performed text-listening) language tasks. A control group (n = 25, average age 45 years) performed the letter-word generation task. RESULTS: Brain tumor patients showed left-lateralization during the antonym-word generation and text-reading tasks at high threshold values and bilateral activation during the letter-word generation task, irrespective of the threshold values. Vascular lesion patients showed left-lateralization during the antonym and letter-word generation, and text-listening tasks at high threshold values. CONCLUSION: Our results suggest that the type of task and the applied statistical threshold influence LI and that the threshold effects on LI may be task-specific. Thus identifying critical functional regions and computing LIs should be conducted on an individual subject basis, using a continuum of threshold values with different tasks to provide the most accurate information for surgical planning to minimize post-operative language deficits.