The small midline occipital encephalomeningocele: definition of a syndrome.

An unusual group of encephalomeningoceles is described. Two children were noted at birth to have a raised area of abnormal skin at the occipital midline. Both of these lesions were found to perforate the superior sagittal sinus and to end between the leaves of the falx cerebri, and to contain a small amount of abnormal cerebral tissue with no connection to either occipital lobe. Previous case reports are reviewed; these lesions are true encephalomeningoceles, rather than glial heterotopias. The embryology of such lesions is considered, and likely differs from the much more common occipital encephalocele arising from one or both occipital lobes.