Cerebral hemiatrophy or Dyke-Davidoff-Masson syndrome is a condition 
characterized by seizures, facial asymmetry, contralateral hemiplegia or 
hemiparesis, and mental retardation. These findings are due to cerebral injury 
that may occur early in life or in utero. The radiological features are 
unilateral loss of cerebral volume and associated compensatory bone alterations 
in the calvarium, like thickening, hyperpneumatization of the paranasal sinuses 
and mastoid cells and elevation of the petrous ridge. The authors describe three 
cases. Classical findings of the syndrome are present in variable degrees 
according to the extent of the brain injury. Pathogenesis is commented.