IDH1 and astrocytoma (excluding glioblastoma): The 2021 World Health Organization (WHO) classification of tumors of central nervous system (CNS) distinguished IDH-wildtype glioblastoma from IDH-mutant astrocytoma; however, cystic glioblastoma is not captured in this classification system or other commonly described molecular profiles (WHO Classification of Tumour Editorial Board, 2021).