Hydranencephaly is a rare congenital abnormality characterized by the absence and replacement of the cerebral hemispheres with cerebrospinal fluid. Here, we present an ultrasonographic diagnosis of a case of a rare variant of fetal hydranencephaly at 38 weeks of gestation. Obstetric sonography revealed the absence of the cerebral cortex, thalami and basal ganglia with a disrupted falx and preserved posterior fossa structures. This is the first reported case of hydranencephaly with the absence of the thalami and basal ganglia, which was diagnosed prenatally. The diagnosis was confirmed with postnatal computed tomography. The early prenatal diagnosis allowed for prompt obstetric attention at a tertiary care hospital which had specialized pediatric facilities including prenatal counseling and support.