Newborn with a brain cyst on prenatal ultrasound

MRI of cavum velum interpositum
Axial (left), coronal (above right) and sagittal (below left) T2 MRI of the brain shows a cerebrospinal fluid space between the atria and trigones of the lateral ventricles, behind the foramen of Monro, beneath the columns of the fornices and above the tela choroidea of the third ventricle.

The diagnosis was cavum velum interpositum.