Recurrent IDH-mutant astrocytoma WHO grade 4 diagnosed during pregnancy: case report with literature review.

High-grade gliomas during pregnancy are exceedingly rare and pose complex clinical challenges. Molecular features such as IDH mutations and CDKN2A/B deletions have become central to diagnosis and prognostication in the 2021 WHO classification of CNS tumors. We report the case of a 31-year-old pregnant woman diagnosed at 24 + 5 weeks of gestation with an IDH1-mutant astrocytoma, WHO Grade 4, harboring a heterozygous CDKN2A/B deletion. She initially presented with progressive neurological symptoms and underwent emergency craniotomy with subtotal tumor resection. Despite early neurosurgical intervention and temporary clinical stabilization, the tumor recurred rapidly within five weeks, prompting a simultaneous cesarean section and re-craniotomy at 31 weeks' gestation. Both mother and infant survived the perioperative period without complications. However, the patient passed away within two years of diagnosis, highlighting the tumor's aggressive course. This case illustrates the poor prognostic implications of CDKN2A/B loss, even in tumors with a favorable IDH mutation status. The molecular profile-especially the presence of any CDKN2A/B deletion-may define a more aggressive subtype of IDH-mutant astrocytoma. Timely neurosurgical intervention, multidisciplinary care, and integrated obstetric-neurosurgical strategies are crucial. There is a pressing need for clinical guidelines addressing high-grade glioma management in pregnancy, particularly in the era of molecular tumor classification.