CNS Tumor with BCOR Internal Tandem Duplication: The First Case in Southeast Asia

Abstract

The central nervous system (CNS) tumor with BCOR internal tandem duplication (ITD) or high-grade neuroepithelial tumor with BCOR alterations (HGNET-BCOR) has been proposed as a new entity of CNS embryonal tumor. We report herein the first case of CNS tumor with BCOR ITD in Southeast Asia. The patient was a 2-year-old girl who presented with head tilt and ataxia. CNS showed a posterior fossa mass, 5.7x5.2x4.2 cm, with faint enhancement and internal hemorrhage. The lesion was removed, and the pathological examination revealed a hypercellular tumor comprising neoplastic cells with oval hyperchromatic nuclei. Perivascular pattern was occasionally observed. Pseudopalisading necrosis was seen but microvascular proliferation was absent. Although the clinical features of HGNET-BCOR are not distinctive and may overlap with other high-grade primary CNS tumors, awareness of the pathological features and the positive BCOR immunostain should lead to a final diagnosis with the identification of BCOR ITD using a molecular method.