Transsphenoidal encephalocele associated with agenesis of corpus callosum: value of metrizamide computed cisternography.

Transsphenoidal encephaloceles are rare congenital malformations that are classified among the medial dysraphias and that are therefore associated with an agenesis of the corpus callosum. Clinically, the diagnosis is difficult, but hypertelorism and weakening eyesight should be of suggestive value. Diagnosis is basically radiological. In the past, it was founded on roentgenography, tomography of the base of the skull, pneumoencephalography, and angiography when necessary. Today, metrizamide computed cisternography using axial transverse and coronal sections, supplemented by sagittal reconstructions, allows for a complete examination of bony, meningeal, and cerebral abnormalities.