Diffuse pediatric-type high-grade glioma (pHGG), RTK1 subtype, is an uncommon aggressive tumor affecting both children and adults. We describe the case of a 66-year-old woman who presented with a left frontal lobe mass. Following surgical resection, the patient developed herpes simplex virus 2 meningoencephalitis, resulting in death. Histological examination revealed a high-grade glioma demonstrating nuclear pleomorphism, high mitotic activity, vascular proliferation and necrosis. The tumor also exhibited oligodendroglial-like features, nuclear clusters and small true rosette-like structures. Genetic analysis identified partial arm 1p loss and 19q loss, PDGFRA, MYCN and MDM4 amplification, an ATRX mutation and a novel SYN2::PPARG fusion. Homozygous CDKN2A/B deletion was also present. Genomic DNA methylation profiling matched diffuse pediatric-type high-grade glioma, RTK1 subtype, subclass C. This case underscores the importance of utilizing advanced molecular and genomic techniques for accurately diagnosing glial tumors. Further study of the SYN2::PPARG fusion in gliomas could potentially offer insights into its role in glioma biology and possibly help elucidate therapeutic strategies for tumors with PPARG fusions.
Brentlinger et al. (Wed,) studied this question.