We describe three children born at term investigated for neonatal seiz
ures or transient apnoea. Cranial ultrasound and MRI unexpectedly reve
aled symmetrical periventricular cysts adjacent to the anterior horns.
We found no evidence of prenatal viral infection, intraventricular or
subependymal haemorrhage or hypoxic-ischaemic lesions. The lesions we
re not seen on MRI at 3 months of age, but there was no compensatory d
ilatation of the anterior horns nor secondary loss of white matter. Th
e appearance and location of these transient cysts were different from
those of the cystic changes which typically follow germinal matrix ha
emorrhage or periventricular leukomalacia. Their pathogenesis and clin
ical significance remain to be determined.