Rosette-forming glioneuronal tumor

Abstract

Rosette-forming glioneuronal tumor (RGNT) is a Grade I tumor, which is classified among neuronal and mixed-glial tumors category of the central nervous system by the World Health Organization in their recent classification [1]. First described as a distinct variant of mixed glioneuronal tumor in 1998, RGNT is a rare, slow-growing neoplasm of the fourth ventricular region, preferentially affecting young adults and composed of a biphasic cytoarchitecture including two distinct histologic components. The first component has uniform neurocytes forming rosettes somewhat resembling Homer Wright rosettes and/or perivascular pseudorosettes; the other is astrocytic in nature and resembles pilocytic astrocytoma (Figure 17.1) [2]. In intraoperative squash smears, the biphasic character of these tumors may cause misdiagnosis due to sampling error; only one part of the tumor may be represented in the smear preparation. © 2018 by Taylor and Francis Group, LLC.