Imaging features of high-grade astrocytoma with piloid features: A single center case series

High-grade astrocytoma with piloid features (HGAP) is a recently described IDH-wildtype tumor with limited literature describing its imaging features. We present our institution's experience and the largest imaging-focused cohort of HGAP reported to date, offering a comprehensive analysis of MRI features of seventeen intracranial and one spinal HGAP, while introducing novel imaging features that have not been previously described. These include focal areas of diffusion restriction, surrounding spiculated, finger-like enhancement and increased perfusion metrics. Additionally, we highlight imaging features of HGAP arising in patients with Neurofibromatosis Type 1, such as intraventricular tumor spread, unusual temporal lobe location and multifocal presentation.