Lateral posterior fossa encephalocele with associated migrational disorder of the cerebellum in an infant.

Encephaloceles are acquired or congenital defects in which intracranial contents protrude through a defect in the calvaria. The embryogenesis of these lesions is incompletely understood. The vast majority of lesions occur at or near the anatomical midline. The authors present an extremely rare case of a laterally oriented, pathologically proven encephalocele associated with a posterior fossa cyst and cerebellar migrational defect in an infant. The authors review past and current theories of encephalocele formation as it relates to this case.