Prenatal diagnosis of isolated agenesis of the septum pellucidum with ultrasound and magnetic resonance imaging

Septo-optic dysplasia is characterized as a midline anomaly with agenesis of the septum pellucidum, optic nerve hypoplasia and pituitary dysfunction. The septal agenesis can occur in isolated form, but its prenatal differentiation from septo-optic dysplasia can be challenging. The isolated agenesis of septum pellucidum is an asymptomatic anatomical variation, based on the few literature data available. We report a case where prenatally performed high magnetic field magnetic resonance imaging helped the differential diagnosis by visualizing and assessing thickness of the optic nerves and chiasma. The development of the infant was followed for 24 months and showed no abnormalities. Our case report confirms that isolated agenesis of the septum pellucidum is probably an asymptomatic variation and the visualization of the optic nerves with high magnetic field fetal MRI could be a crucial point of the differential diagnosis and provide possibility to exclude septo-optic dysplasia in utero.