Atretic cephalocele - an uncommon cause of cystic scalp mass.

A 6 year-old girl presented with a midline parietal scalp swelling that had been gradually enlarging since birth. Magnetic resonance imaging revealed communication of the cyst with the subarachnoid space through a calvarial defect, with concomitant findings of vertically positioned straight venous sinus and subependymal grey matter heterotopia. A diagnosis of atretic cephalocele was thus made based on these classical imaging findings.