Methylation Profiling Improves the Care of Pediatric Brain Tumor Patients

Abstract We describe a pediatric patient with an intra-axial tumor; histopathologic examination of the resected specimen was unable to establish a precise diagnosis. While the initial targeted next-generation sequencing (NGS) panel was also nondiagnostic, genomic DNA methylation profiling indicated that the tumor was an astroblastoma, MN1-altered. A more comprehensive NGS panel was then run, which confirmed an MN1-BEND2 fusion. This case displays the limitations and pitfalls of a histological and immunohistochemical-based diagnosis in a case of an infrequently encountered pediatric brain tumor. Furthermore, it highlights the growing need for performing DNA methylation, paired with a comprehensive NGS panel, to ensure an accurate diagnosis in modern surgical neuropathology.