title: Atypical external hydrocephalus with visual failure due to occult leptomeningeal dissemination of a pontine glioma. Case report.
abstract: The authors report on the case of a diffuse pontine glioma in a 5-year-old boy in whom radiologically and cytologically occult leptomeningeal metastases led to the development of an atypical "external" hydrocephalus, associated with grossly elevated intracranial pressure (ICP). Initial neuroimaging demonstrated only mild communicating ventricular dilation associated with a noticeable enlargement of the subarachnoid space, particularly over the surface of the frontal lobes; these features are not usually associated with significantly elevated ICP. Possible pathophysiological mechanisms resulting in this unusual clinical presentation are discussed. Early recognition of the severity of the raised ICP despite the paucity of clinical and radiological signs may have averted the development of blindness due to optic atrophy.
authors.affiliation: Department of Neurosurgery, Frenchay Hospital, Bristol; and Department of Paediatric Oncology, Bristol Royal Hospital for Sick Children, Bristol, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Tarnaris
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Edwards
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Lowis
authors.forename: Ian K
authors.initials: IK
authors.lastname: Pople
mesh_terms: D001706:Biopsy; D020295:Brain Stem Neoplasms / Q000473:pathology* / Q000532:radiotherapy; D002540:Cerebral Cortex / Q000473:pathology; D002675:Child, Preschool; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D005625:Frontal Lobe / Q000473:pathology; D005909:Glioblastoma / Q000473:pathology* / Q000532:radiotherapy; D006801:Humans; D006849:Hydrocephalus / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D019586:Intracranial Hypertension / Q000175:diagnosis / Q000209:etiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology* / Q000532:radiotherapy; D009361:Neoplasm Invasiveness; D009802:Oculomotor Nerve / Q000473:pathology; D009896:Optic Atrophy / Q000209:etiology / Q000473:pathology; D011832:Radiation Injuries / Q000150:complications; D011878:Radiotherapy / Q000009:adverse effects; D013129:Spinal Puncture; D013346:Subarachnoid Space / Q000473:pathology