Pure neuronal and mixed neuronal-glial tumors of the central nervous system are uncommon but fascinating because they are less aggressive than the more common glial tumors and their prognosis is excellent. Neurologic manifestations are varied and include seizures, symptoms of increased intracranial pressure, and neurologic deficits according to tumor location. Many neuronal tumors of the central nervous system demonstrate characteristic radiologic findings. At magnetic resonance (MR) imaging, gangliocytomas demonstrate low signal intensity on T1-weighted images, high signal intensity on T2-weighted images, and frequent enhancement on gadolinium-enhanced T1-weighted images. Characteristic MR imaging findings of Lhermitte-Duclos disease are a nonenhancing mass in a cerebellar hemisphere with a striated pattern. Central neurocytomas are typically located in the lateral ventricles near the foramen of Monro with a characteristic attachment to the septum pellucidum. Ganglioneurocytoma is a rare variant of central neurocytoma that is characterized by differentiation toward ganglion cells. In ganglioglioma, a well-defined cystic mass with a solid mural nodule is typically seen. Extension of enhancement to the leptomeninges is characteristic of desmoplastic infantile ganglioglioma and correlates with the firm dural attachment of the solid component. Dysembryoplastic neuroepithelial tumor has a well-demarcated, multilobulated or gyriform appearance.

Chordomas and chondrosarcomas occur rarely in the skull base and have been often considered commonly with respect to the management. The aim of this study was to investigate the clinical results in each series of these tumors and analyze comparative outcome. Between 1991 and 2005, 30 consecutive patients with pathological diagnosis of chordoma (n=19) or chondrosarcoma (n=11) of the skull base were managed by multimodal treatment combining surgical resection with conventional photon radiotherapy and/or gamma knife radiosurgery. A retrospective analysis was conducted on these patients (aged 3 to 69 years; mean age of 37.3 years; 17 females and 13 males; mean follow-up of 56.1 months). Four deaths occurred among the patients with chordoma. The progression-free survival rate at 3 and 5 years was 61.5 and 40.0% in chordoma. In contrast, no mortalities were observed, and there was only one recurrence among the patients with chondrosarcoma. The progression-free survival rate at 3 and 5 years was 88.9 and 80.0% in chondrosarcoma. Among 15 survivors with chordoma, four patients were suffering from severe disability with progressive disease. On the other hand, most patients with chondrosarcoma harbored stable disease and less disabling symptoms except one instance of recurrence. As the biological behavior of chordoma is much more aggressive than that of chondrosarcoma in the skull base, one should make a distinction between these entities to plan an optimal treatment strategy.

Gliosarcoma (GS) is a rare variant (2%) of glioblastoma (GBM) that poses clinical genomic challenges because of its poor prognosis and limited genomic information. To gain a comprehensive view of the genomic alterations in GS and to understand the molecular etiology of GS, we applied whole-exome sequencing analyses for 28 GS cases (6 blood-matched fresh-frozen tissues for the discovery set, 22 formalin-fixed paraffin-embedded tissues for the validation set) and copy-number variation microarrays for 5 blood-matched fresh-frozen tissues. TP53 mutations were more prevalent in the GS cases (20/28, 70%) compared to the GBM cases (29/90, 32%), and the GS patients with TP53 mutations showed a significantly shorter survival (multivariate Cox analysis, hazard ratio=23.9, 95% confidence interval, 2.87–199.63, P=0.003). A pathway analysis showed recurrent alterations in MAPK signaling (EGFR, RASGRF2 and TP53), phosphatidylinositol/calcium signaling (CACNA1s, PLCs and ITPRs) and focal adhesion/tight junction (PTEN and PAK3) pathways. Genomic profiling of the matched recurrent GS cases detected the occurrence of TP53 mutations in two recurrent GS cases, which suggests that TP53 mutations play a role in treatment resistance. Functionally, we found that TP53 mutations are associated with the epithelial–mesenchymal transition (EMT) process of sarcomatous components of GS. We provide the first comprehensive genome-wide genetic alternation profiling of GS, which suggests novel prognostic subgroups in GS patients based on their TP53 mutation status and provides new insight in the pathogenesis and targeted treatment of GS.