John P. Provias

Molecular biomarkers, such as IDH1/IDH2 mutations and 1p19q co-deletion, are included in the histopathological and clinical criteria currently used to diagnose and classify gliomas. IDH1/IDH2 mutation is a common feature of gliomas and is associated with a glioma-CpG island methylator phenotype (CIMP). Aberrant genomic methylation patterns can also be used to extrapolate information about copy number variation in a tumor. This project’s goal was to assess the feasibility of DNA methylation array for the simultaneous detection of glioma biomarkers as a more effective testing strategy compared to existing single analyte tests. Methods: Whole-genome methylation array (WGMA) testing was performed using 48 glioma DNA samples to detect methylation aberrations and chromosomal gains and losses. The analyzed samples include 39 tumors in the discovery cohort and 9 tumors in the replication cohort. Methylation profiles for each sample were correlated with IDH1 p.R132G mutation, immunohistochemistry (IHC), and previous 1p19q clinical testing to assess the sensitivity and specificity of the WGMA assay for the detection of these variants. Results: We developed a DNA methylation signature to specifically distinguish a IDH1/IDH2 mutant tumor from normal samples. This signature is composed of 11 CpG sites that were significantly hypermethylated in the IDH1/IDH2 mutant group. Copy number analysis using WGMA data was able to identify five of five positive samples for 1p19q co-deletion and was concordant for all negative samples. Conclusions: The DNA methylation signature presented here has the potential to refine the utility of WGMA to predict IDH1/IDH2 mutation status of gliomas, thus improving diagnostic yield and efficiency of laboratory testing compared to single analyte IDH1/IDH2 or 1p19q tests.

A child had been followed since infancy by our multi-disciplinary neuro-oncology clinic with annual magnetic resonance imaging (MRI) under the presumed diagnosis of encephalocraniocutaneous lipomatosis (ECCL), with clinical features including nevus psiloliparus, scalp lipoma, nodular skin tag on and coloboma of the eyelid, cortical atrophy and meningeal angiomatosis. At the age of 4, she was found to have a large temporoparietal lesion causing elevated intracranial pressure requiring surgical resection. Histopathological exam of the tumor was suggestive of an intracranial sarcoma. Sequencing analysis of the tumor revealed mutations in DICER1, KRAS and TP53. Subsequent germline testing confirmed DICER1 syndrome and revealed an insignificant FGFR1 variant at a low frequency. Methylation profile of the tumor showed the tumor clustered most closely with sarcoma (rhabdomyosarcoma-like), confirming this tumor to be a primary DICER1-sarcoma. Compared to the previously reported cases, our unique case of primary DICER1-sarcoma also demonstrated neurofilament and chromogranin positivity, and genomic instability with loss of chromosome 4p, 4q, 8p, 11p, and 19p, as well as gains in chromosome 7p, 9p, 9q, 13q, and 15q on copy variant analysis. The detailed sequencing and methylation information discovered in this unique case of DICER1-sarcoma will hopefully help further our understanding of this rare and emerging entity.

Gangliogliomas represent a rare form of neuroepithelial tumor (up to 1.3% of brain tumors [1]), which even more rarely present with hemorrhage or localize intraventricularly. To date, only two cases of ganglioglioma with both of these features have been reported. Our patient is a 23-year-old woman who presented with signs and symptoms of increased intracranial pressure (ICPI), with a post-subtotal resection diagnosis of WHO Grade I ganglioglioma localizing bilaterally to the lateral ventricles. One year following the operation, the tumor showed radiologic evidence of interval hemorrhage, which was verified histopathologically following a second subtotal resection. Greater than 95% of the lesion represented a large hematoma with organization and well-defined fibrous pseudo-capsule, with very scanty fragments of adjacent/peripheral low-grade neuroglial tumor. This case represents a very rare presentation of intraventricular ganglioglioma with extensive hemorrhage. .

Time-resolved fluorescence (TRF) and diffuse reflectance (DR) spectroscopy are two optical biopsy modalities that have been studied in tumor diagnosis. Combination of TRF and DR spectroscopy allows us to obtain more features such as fluorescence intensity, lifetime, and optical properties; thus, potentially improving the tissue diagnostic accuracy. In this paper, an integrated TRF-DR spectroscopy instrument was developed to acquire TRF spectra as well as spatially resolved diffuse reflectance spectra in sequence for intraoperative detection of brain tumor margin. The performance of TRF-DR spectroscopy instrumentation was calibrated and evaluated using endogenous biomolecules, tissue phantoms, and ex vivo brain tumor specimens. The results demonstrated that the TRF-DR system is capable to retrieve the fluorescence and optical properties accurately.

Congenital brain tumors are rare, accounting for 0.5% to 4% of all pediatric brain tumors. A 10-year retrospective study based on autopsy and neurosurgical clinical reports with a diagnosis of congenital/fetal/neonatal brain tumor identified 6 cases. Four cases were diagnosed antenatally by neuroradiology. Clinical outcomes in 5 cases resulted in death; 1 patient with choroid plexus papilloma underwent successful resection of the tumor and is still alive. Tumor pathologies consisted of 2 teratomas, 2 choroid plexus papillomas, 1 gemistocytic astrocytoma, and 1 glioblastoma multiforme. A literature review of all fetal cases specific to the pathologies presented in this series was also performed. Relative to the literature, this series contains a rare case of congenital gemistocytic astrocytoma. This series further sheds light on the diagnostic, histological, prognostic, and therapeutic differences between congenital brain tumors and tumors of the same pathology in older pediatric and adult populations.

Hemimegalencephaly (HME) is a developmental abnormality of the central nervous system, identified by an abnormal increase in the size of one cerebral hemisphere. HME may present as either a syndromic or isolated case. To date the literature on HME has focused primarily on non-fetal pediatric patients, largely related to surgical resection specimens of the HME hemisphere. We present the case of a male fetus at 22 weeks gestation with intracranial abnormalities identified on a follow-up ultrasound. Gross examination of the fetal brain confirmed the increased size of the right cerebral hemisphere. The ipsilateral brain stem and cerebellum were not involved. Light microscopy demonstrated the presence of accelerated cortical differentiation along with several migrational anomalies in the HME hemisphere. Based on the gross and microscopic findings, a diagnosis of fetal hemimegalencephaly was made. The periventricular proliferative zone of the abnormal hemisphere contained a normal population of neuroepithelial precursor cells. An exhaustive immunohistochemical study found immunoreactivity for calretinin and synaptophysin, while the Ki-67 proliferation labeling was not increased in the HME hemisphere. Our case is the first autopsied report on fetal hemimegalencephaly and confirms that the key pathogenic changes may present as early as 20–22 weeks gestation. The major pathological features of our case are in keeping with a disturbance in accelerated neuronal differentiation and migrational abnormalities.

Salmonella meningitis is a rare and serious infection of the central nervous system following acute Salmonella enterica sepsis. For this pathogen, no appropriate model has been reported in which to examine infection kinetics and natural dissemination to the brain. Five mouse lines including C57BL/6, Balb/c, 129S6-Slc11a1tm1 ^Mcg , 129S1/SvImJ, B6.129-Inpp5dtm1 ^Rkh were used in the murine typhoid model to examine the dissemination of systemic Salmonella enterica serovar Typhimurium following oral infection. We report data on spontaneous meningitis and brain infection following oral infection of mice with Salmonella enterica serovar Typhimurium. This model may provide a system in which dissemination of bacteria through the central nervous system and the influence of host and bacterial genetics can be queried.