Assuntos
Fusão Gênica , Glioma/genética , Neoplasias de Tecido Nervoso/genética , Proteínas Proto-Oncogênicas B-raf/genética , Deleção de Sequência , Neoplasias da Medula Espinal/genética , Adolescente , Pré-Escolar , Feminino , Seguimentos , Glioma/diagnóstico por imagem , Glioma/metabolismo , Glioma/patologia , Humanos , Masculino , Gradação de Tumores , Neoplasias de Tecido Nervoso/diagnóstico por imagem , Neoplasias de Tecido Nervoso/metabolismo , Neoplasias de Tecido Nervoso/patologia , Medula Espinal/diagnóstico por imagem , Medula Espinal/metabolismo , Medula Espinal/patologia , Neoplasias da Medula Espinal/diagnóstico por imagem , Neoplasias da Medula Espinal/metabolismo , Neoplasias da Medula Espinal/patologia , Adulto JovemRESUMO
BACKGROUND: Dysembryoplastic neuroepithelial tumors (DNETs) are uncommon neural tumors presenting most often in children and young adults and associated with intractable seizures. Rare midline neoplasms with similar histological features to those found in DNETs have been described near the septum pellucidum and termed "DNET-like neoplasms of the septum pellucidum." Due to their rarity, these tumors have been described in just a few reports and their genetic alterations sought only in small series. METHODS: We collected 20 of these tumors for a comprehensive study of their clinical, radiological, and pathological features. RNA sequencing or targeted DNA sequencing was undertaken on 18 tumors, and genome-wide DNA methylation profiling was possible with 11 tumors. Published cases (n = 22) were also reviewed for comparative purposes. RESULTS: The commonest presenting symptoms and signs were related to raised intracranial pressure; 40% of cases required cerebrospinal fluid diversion. Epilepsy was seen in approximately one third of cases. All patients had an indolent disease course, despite metastasis within the neuraxis in a few cases. Radiologically, the septum verum/septal nuclei were involved in all cases and are the proposed site of origin for septal DNET (sDNET). Septal DNET showed a high frequency (~80%) of mutations of platelet derived growth factor receptor A (PDGFRA), and alterations in fibroblast growth factor receptor 1 (FGFR1) and neurofibromatosis type 1 (NF1) were also identified. In a genomic DNA methylation analysis alongside other neural tumors, sDNETs formed a separate molecular group. CONCLUSIONS: Genetic alterations that are different from those of cerebral DNETs and a distinct methylome profile support the proposal that sDNET is a distinct disease entity.