title: "Acquired" Chiari I malformation. Case report.
abstract: Tonsillar descent of the cerebellum in Chiari I malformations is often considered a congenital defect. A patient is presented in whom magnetic resonance (MR) imaging revealed normally positioned cerebellar tonsils; however, 1 year later MR imaging was repeated for evaluation of gait abnormalities and showed descent of the cerebellar tonsils. This case illustrates worsening symptoms with progressive descent of the cerebellar tonsils and suggests that Chiari I malformations can evolve postnatally.
authors.affiliation: Department of Neurosurgery, New York University Medical Center, New York.
authors.forename: P P
authors.initials: PP
authors.lastname: Huang
authors.forename: S
authors.initials: S
authors.lastname: Constantini
mesh_terms: D001139:Arnold-Chiari Malformation / Q000175:diagnosis*; D002531:Cerebellum / Q000002:abnormalities; D004677:Encephalocele / Q000175:diagnosis; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging