Crossed cerebellar atrophy in children: a neurologic sequela of extreme prematurity.

Unilateral atrophy of a cerebellar hemisphere occurring as a sequela of ischemic or destructive injury of the contralateral cerebral hemisphere is uncommon in children. We reviewed our experience with this phenomenon and found an unexpected association with extreme prematurity and a complicated perinatal course with a poor subsequent neurologic outcome. We retrospectively identified eight children, aged 8 months to 13 years, in whom cerebellar atrophy associated with cerebral injury was diagnosed on MR or CT, and reviewed their past medical history, neurologic findings, and neuroimaging studies. Seven patients were born extremely premature, EGA 25-28 weeks, and had severe perinatal intracranial hemorrhage. Neurologic problems include severe developmental delay in seven, spastic paresis in six, and seizures in five. Neuroimaging showed severe unilateral holohemispheric atrophy in four, bilateral asymmetric holohemispheric atrophy in two, and left temporoparietal atrophy in one. Cerebellar atrophy was unilateral in five and bilateral but asymmetric in two. Gliosis of the atrophic cerebellum occurred in one patient. Sequential neuroimaging in one patient showed evolution of crossed cerebellar atrophy at 8 months of age. The final patient, a term infant, had an idiopathic perinatal left cerebral infarct. In our experience, crossed cerebellar atrophy was an uncommon manifestation of extreme prematurity complicated by severe intracranial hemorrhage and/or ischemic necrosis of white matter. The cerebellar atrophy is most often a secondary degenerative phenomenon rather than a result of direct cerebellar injury.