The role of methylation profiling in histologically diagnosed neurocytoma: a case series

Molecular and clinical characterization of atypical central neurocytomas: implications for diagnosis and treatment strategies

OBJECTIVES

This study aimed to investigate the histological and molecular characteristics of atypical central neurocytomas (CNs) and evaluate their clinical treatment outcomes, with the aim of identifying reliable biomarkers for differentiation and optimal treatment strategies.

METHODS

We conducted a retrospective study including 61 patients diagnosed with CNs. Clinical data, neuroimaging, and pathological findings were analyzed. RNA sequencing was performed on tumor tissues to identify differentially expressed genes.

RESULTS

Histological atypia and the Ki-67 index showed no significant impact on progression-free survival (PFS) or overall survival (OS). RNA sequencing identified significant genetic alterations in pathways such as neuroactive ligand-receptor interaction, cAMP, MAPK, and Ras signaling. Differently expressed genes included AMOTL1, PIK3R3, TGFBR1, SMO, COL4A6, MGP, SOX4, IGF2, SLIT1, and CKS2. The five-year OS rate (p = 0.015) and PFS rate (p = 2.00 × 10-6) were significantly higher in the complete resection (CR) group compared to the incomplete resection (IR) group. Postoperative radiotherapy did not affect OS or PFS in the CR group. The five-year PFS rate (p = 3.80 × 10-5) was significantly longer in patients in the CR group who did not receive radiotherapy compared to those in the IR group who did receive radiotherapy. The extent of surgical resection and operative approaches were found to be irrelevant to perioperative complications and dysfunctions at the last follow-up.

CONCLUSION

CR is crucial for a better prognosis in patients with atypical CNs. Additional radiotherapy after CR offers little benefit. Histological atypia and the Ki-67 index are not effective in distinguishing between atypical and typical CNs. Identified genetic alterations provide insights into the aggressive behavior of atypical CNs, suggesting potential therapeutic targets and underscoring the need for further research to optimize treatment strategies.

Central Neurocytoma Treated Using Supratentorial Ventricle Radiotherapy: A Single-Institution Analysis of Five Cases in Adjuvant or Salvage Settings After Surgery

INTRODUCTION

Central neurocytoma (CN) is an extremely rare tumor primarily located in the supratentorial ventricular system, categorized as a glioneuronal or neuronal tumor.

METHODS

This study presented a retrospective analysis of five CN patients who received adjuvant or salvage radiotherapy. Patients, aged 31-59 years, underwent radiation doses ranging from 60 Gy to 50.4 Gy over 27-30 fractions.

RESULTS

All patients achieved effective local tumor control without severe complications. The median follow-up period was 51.7 months, demonstrating 100% overall and progression-free survival rates.

DISCUSSION

Our study's clinical outcomes align with previous research, despite the limitation of a small sample size. Emphasizing the necessity for additional research, our findings added to the potential evidence of radiotherapy in managing CN. Larger, long-term studies were needed to confirm these promising results.

Whole-exome sequencing reveals genetic variants that may play a role in neurocytomas

OBJECTIVES

Neurocytomas (NCs) are rare intracranial tumors that can often be surgically resected. However, disease course is unpredictable in many patients and medical therapies are lacking. We have used whole exome sequencing to explore the molecular etiology for neurocytoma and assist in target identification to develop novel therapeutic interventions.

METHODS

We used whole exome sequencing (WES) to compare the molecular landscape of 21 primary & recurrent NCs to five normal cerebellar control samples. WES data was analyzed using the Qiagen Clinical Insight program, variants of interest (VOI) were interrogated using ConSurf, ScoreCons, & Ingenuity Pathway Analysis Software to predict their potential functional effects, and Copy number variations (CNVs) in the genes of interest were analyzed by Genewiz (Azenta Life Sciences).

RESULTS

Of 40 VOI involving thirty-six genes, 7 were pathogenic, 17 likely-pathogenic, and 16 of uncertain-significance. Of seven pathogenic NC associated variants, Glucosylceramidase beta 1 [GBA1 c.703T > C (p.S235P)] was mutated in 5/21 (24%), Coagulation factor VIII [F8 c.3637dupA (p.I1213fs*28)] in 4/21 (19%), Phenylalanine hydroxylase [PAH c.975C > A (p.Y325*)] in 3/21 (14%), and Fanconi anemia complementation group C [FANCC c.1162G > T (p.G388*)], Chromodomain helicase DNA binding protein 7 [CHD7 c.2839C > T (p.R947*)], Myosin VIIA [MYO7A c.940G > T (p.E314*)] and Dynein axonemal heavy chain 11 [DNAH11 c.3544C > T (p.R1182*)] in 2/21 (9.5%) NCs respectively. CNVs were noted in 85% of these latter 7 genes. Interestingly, a Carboxy-terminal domain RNA polymerase II polypeptide A small phosphatase 2 [CTDSP2 c.472G > A (p.E158K)] of uncertain significance was also found in > 70% of NC cases.

INTERPRETATION

The variants of interest we identified in the NCs regulate a variety of neurological processes including cilia motility, cell metabolism, immune responses, and DNA damage repair and provide novel insights into the molecular pathogenesis of these extremely rare tumors.

Intraventricular central neurocytoma molecularly defined as extraventricular neurocytoma: a case representing the discrepancy between clinicopathological and molecular classifications

Central neurocytoma (CN) is classically defined by its intraventricular location, neuronal/neurocytic differentiation, and histological resemblance to oligodendroglioma. Extraventricular neurocytoma (EVN) shares similar histological features with CN, while it distributes any site without contact with the ventricular system. CN and EVN have distinct methylation landscapes, and EVN has a signature fusion gene, FGFR1-TACC1. These characteristics distinguish between CN and EVN. A 30-year-old female underwent craniotomy and resection of a left intraventricular tumor at our institution. The histopathology demonstrated the classical findings of CN. Adjuvant irradiation with 60 Gy followed. No recurrence has been recorded for 25 years postoperatively. RNA sequencing revealed FGFR1-TACC1 fusion and methylation profile was discrepant with CN but compatible with EVN. We experienced a case of anatomically and histologically proven CN in the lateral ventricle. However, the FGFR1-TACC1 fusion gene and methylation profiling suggested the molecular diagnosis of EVN. The representative case was an "intraventricular" neurocytoma displaying molecular features of an "extraventricular" neurocytoma. Clinicopathological and molecular definitions have collided in our case and raised questions about the current definition of CN and EVN.

Central neurocytoma-positive and differential diagnosis: An example through a case report

Central neurocytoma is a rare intraventricular tumor, occurring typically in the lateral ventricle of young adults. It is considered as a neuronal-glial benign tumor with favorable prognosis. Imaging is a cornerstone allowing the accurate preoperative diagnosis on the basis of several characteristic features. We report the case of a 31-year-old man who has been complaining of progressive headaches and in whom brain magnetic resonance imaging revealed a central neurocytoma. We remind then, through a literature review, the main criteria to set the diagnosis of this tumor and rule out the other possible diagnoses.