Histologic spectrum and molecular subgroups of ependymal tumors

Abstract

Ependymal tumors are relatively infrequent neuroepithelial neoplasms, but they have a wide and complex histologic spectrum including subtypes and variants recognized by the current Word Health Organization (WHO), and some special morphologic variants or growth patterns such as giant cell morphology, melanin differentiation, signet - ring, fat or vacude metaplasia, cartilage metaplasia with or without bone formation, oncocytic, epithelioid, and so on. Pathologists need to pay attention to identification and differential diagnosis of these special morphologic variants. Genomic and DNA methylation profiling studies have defined nine distinct molecular subgroups of ependymal tumors. RELA fusion - positive ependymoma has now been designated as one of the distinctive molecular variants of ependymoma by 2016 WHO classification of central nervous system tumors. Risk stratification by molecular subgrouping is superior to histological grading. However, how to integrated molecular genetic features into the histological spectrum need to be further researched.

DOI: 10.3969/j.issn.1672-6731.2017.10.002