Subacute sclerosing panencephalitis: brain stem involvement in a peculiar pattern.

The most common pattern in subacute sclerosing panencephalitis, is in the cerebral hemisphere white matter on T2-weighted images with or without atrophy. Brain-stem lesions are rare. We report brain-stem involvement in two children with subacute sclerosing panencephalitis. A peculiar pattern, with involvement of the pons with extension to both middle cerebellar peduncles and substantia nigra but sparing the pontine tegmentum, is suggested.