Hydranencephaly Secondary to Placental Fetal Vascular Malperfusion in a Pregnancy with Extensive Uterine Fibromatosis

INTRODUCTION: Hydranencephaly is a rare, destructive fetal brain disorder usually attributed to early bilateral carotid occlusion. CASE PRESENTATION: We report a 34-year-old primigravida with extensive uterine fibromatosis whose fetus showed normal neurosonography at 13 + 1 weeks, rapidly evolving to severe ventriculomegaly and near-complete supratentorial destruction by 18 weeks, with normal karyotype, array-CGH, and noncontributory exome sequencing. Postmortem examination confirmed classic hydranencephaly with preserved deep gray nuclei and a small cerebellum, while both carotid arteries were patent. Placental histology revealed multifocal avascular villi and umbilical cord lesions consistent with fetal vascular malperfusion, indicating chronic, likely intermittent impairment of fetal blood flow. CONCLUSION: This case supports a primary ischemic-vascular mechanism mediated through placental fetal vascular malperfusion rather than malformative or genetic causes and highlights the importance of systematic placental assessment in destructive fetal brain lesions.