Central neurocytoma: establishment of the disease entity

Central neurocytoma exhibits radial glial cell signatures with FGFR3 hypomethylation and overexpression

We explored the genomic events underlying central neurocytoma (CN), a rare neoplasm of the central nervous system, via multiomics approaches, including whole-exome sequencing, bulk and single-nuclei RNA sequencing, and methylation sequencing. We identified FGFR3 hypomethylation leading to FGFR3 overexpression as a major event in the ontogeny of CN that affects crucial downstream events, such as aberrant PI3K-AKT activity and neuronal development pathways. Furthermore, we found similarities between CN and radial glial cells based on analyses of gene markers and CN tumor cells and postulate that CN tumorigenesis is due to dysregulation of radial glial cell differentiation into neurons. Our data demonstrate the potential role of FGFR3 as one of the leading drivers of tumorigenesis in CN.

Clinicopathological features and treatment outcome of central neurocytoma: a single institute experience

Background

Despite the increased interest in publishing data on central neurocytoma, its management remains controversial. The overall incidence is approximately 0.5% of brain tumors. The reporting of institutional experience is of major need for such category of tumors to increase our knowledge and experience. In this study, we describe the clinical presentation, pathological data, and treatment outcomes of central neurocytoma.

Results

Medical records of patients with neurocytoma treated in our center from July 2008 to December 2018 were retrospectively reviewed. Extra ventricular neurocytomas were excluded from analysis due to the known aggressive behavior compared to central neurocytoma. Seventeen patients treated at our center as central neurocytoma were included in the study. The frequent clinical presentation was headaches (58.8%) and paresis (35.3%). Ten patients (58.8%) developed symptoms before the age of 30 years. All patients were treated with surgical resection. Gross total resection was performed in 11 cases (64.7%) and subtotal resection was performed in 3 cases (17.7%). Four patients developed disease progression following the first excision (23.5%), for which additional resection was performed. Two patients received fractionated radiotherapy; one after the first resection due to residual disease postoperatively and the other patient following the third excision due to multiple recurrences with radiotherapy doses of 50.4 Gy and 54 Gy, respectively. The median follow-up time was 51 months (range of 14–106). The 5-year progression-free survival was 70 ± 13%. The overall survival for our cohort of patients was 100%.

Conclusions

Central neurocytoma is a rare tumor of neuronal origin and surgery is the mainstay of treatment with a favorable prognosis. Adjuvant radiotherapy can be offered in patients with residual disease or multiple recurrences, especially in patients with tumors of high MIC-1 LI.

Glioneuronal tumors: clinicopathological findings and treatment options

Glioneuronal tumors are very rare CNS neoplasms that demonstrate neuronal differentiation, composed of mixed glial and neuronal cells. The majority of these lesions are low grade and their correct classification is crucial in order to avoid misidentification as ‘ordinary’ gliomas and prevent inappropriate aggressive treatment; nevertheless, precise diagnosis is a challenge due to phenotypic overlap across different histologic subtype. Surgery is the standard of therapeutic approach; literature concerning the benefit of adjuvant treatments is inconclusive and a globally accepted treatment of recurrence does not exist. Targetable mutations in the genes BRAF and FGFR1/2 are recurrently found in these tumors and could take a promising role in future treatment management.