Histopathological, molecular, clinical and radiological characterization of rosette-forming glioneuronal tumor in the central nervous system

Abstract

ObjectiveA rosette-forming glioneuronal tumor (RGNT) is a rare entity originally described in the fourth ventricle. Recently, RGNTs occurring in extraventricular sites and those with malignant behaviors have been reported. The purpose of this study was to analyze the clinicoradiological and histopathological features, therapeutic strategies, and outcomes of RGNTs.MethodsWe enrolled 38 patients diagnosed with RGNTs pathologically between August 2009 and June 2016. CT and MRI, including diffusion-weighted imaging and spectroscopy, were performed. The surgical treatment and histopathological and molecular features were assessed. Additionally, we searched the relevant literatures and performed a pooled analysis of individual patient data. The potential risk factors of prognosis were analyzed.ResultsOur case series included 22 male and 16 female patients, with a mean age of 25.9 years. RGNTs involved the fourth ventricle (26.3%), cerebella (34.2%), supratentorial ventricular system (13.2%), spinal cord (10.5%), temporal lobe (10.5%), thalamus (7.9%), brain stem (7.9%), frontal lobe (5.3%), pineal region (5.3%), suprasellar region (2.6%), and basal ganglia (2.6%). Statistical analyses showed that pediatric age, purely solid appearance of the tumor, and inadequate resection (only partial removal or biopsy) were risk factors associated with progression events. Patients with subtotal resection appeared to do as well as those with gross total resection.ConclusionsRGNTs can occur nearly anywhere in the CNS, at both supratentorial and infratentorial sites. Maximal safe surgical resection should be emphasized for treatment; whilst aggressive resection with the goal of complete resection may be unnecessary.

An epilepsy‐associated glioneuronal tumor with mixed morphology harboring FGFR1 mutation

“…Rosette‐forming glioneuronal tumor is a slow‐growing GNT commonly occurring in young adults . While RGNT usually occupies the fourth ventricle, it can affect almost anywhere in the CNS including the temporal lobe . Histologically, the neuronal component contains uniform neurocytes surrounding an eosinophilic neuropil core and/or small vessels which forms unique neurocytic rosettes or perivascular pseudorosettes.…”

“…1 While RGNT usually occupies the fourth ventricle, it can affect almost anywhere in the CNS including the temporal lobe. [4][5][6] Histologically, the neuronal component contains uniform neurocytes surrounding an eosinophilic neuropil core and/or small vessels which forms unique neurocytic rosettes or perivascular pseudorosettes. The glial component resembles PA and might contain OLCs.…”

“…Rosette‐forming glioneuronal tumor, which was originally described as a distinctive tumor of the posterior fossa, is a slow‐growing GNT that most commonly affects young adults . While the posterior fossa is a predominant site, RGNT can arise almost anywhere in the CNS . RGNT frequently displays classic features of PA, such as being biphasic, microcystic, containing OLCs.…”

“…1 While the posterior fossa is a predominant site, RGNT can arise almost anywhere in the CNS. [4][5][6] RGNT frequently displays classic features of PA, such as being biphasic, microcystic, containing OLCs. FGFR1 mutation, which can be occasionally seen in PA, is detected in a subset of RGNT particularly tumors of extra-cerebellar and midline location.…”

A case of recurrent epilepsy‐associated rosette‐forming glioneuronal tumor with anaplastic transformation in the absence of therapy

“…Rosette‐forming glioneuronal tumor (RGNT) is a WHO grade I neoplasm usually occurring adjacent to or within the fourth ventricle, but is also described in other anatomic locations . Histologic findings include two distinct morphologic components, one exhibiting neurocytic rosettes or perivascular pseudorosettes, and another component with fibrillary astrocytic cells similar to pilocytic astrocytoma .…”