CNS tumor with EP300::BCOR fusion: discussing its prevalence in adult population

Abstract

The Central Nervous System (CNS) tumor with BCOR internal tandem duplication (ITD) has recently been added as a novel embryonal histomolecular tumor type to the 2021 World Health Organization (WHO) Classification of CNS Tumors. In addition, other CNS tumors harboring a BCOR/BCORL1 fusion, which are defined by a distinct DNA-methylation profile, have been recently identified in the literature but clinical, radiological and histopathological data remain scarce. Herein, we present two adult cases of CNS tumors with EP300::BCOR fusion. These two cases presented radiological, histopathological, and immunohistochemical homologies with CNS tumors having BCOR ITD in children. To compare these tumors with different BCOR alterations, we performed a literature review with a meta-analysis. CNS tumors with EP300::BCOR fusion seem to be distinct from their BCOR ITD counterparts in terms of age, location, progression-free survival, tumor growth pattern, and immunopositivity for the BCOR protein. CNS tumors from the EP300::BCOR fusion methylation class in adults may be added to the future WHO classification.

Diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters (DGONC), new name and new problems: an illustration of one case with atypical morphology and biology

“…The variety of histopathology and grading (neurocytic from embryonal morphology with neuropil islands and spongioblastic features) in association with the co-expression of OLIG2 and neuronal markers may morphologically resemble CNS NB-FOXR2 [2,6]. However, in contrast to the aforementioned tumors, DGONC expresses SOX10, which may potentially be important for a diagnosis [7]. A chromosome 1q gain, which is almost always observed in CNS NB-FOXR2, may also be encountered in DGONC (19/35 reported cases, 54%) [1,5,6].…”