Abstract
A giant fusiform aneurysm of the basilar artery was present in a 10-year-old boy with a 2-year history of intermittent headaches and the acute onset of neurologic signs. Elevated sedimentation rate, cerebrospinal fluid pleocytosis, and an apparent response to corticosteroid therapy suggest a chronic inflammatory vascular process. The uniqueness of this aneurysm in a child and the possible underlying arteriopathies are discussed. © 1977 American Academy of Neurology.