title: MR of leptomeningeal melanosis in children.
abstract: OBJECTIVE
  To delineate the magnetic resonance (MR) appearance of leptomeningeal melanosis in children.
  
  
  METHODS
  Retrospective review of the medical, surgical, pathologic and MR findings in four children with a confirmed histologic diagnosis of leptomeningeal melanosis. The brain MR was performed with T1- and T2-weighted images in all four children and three had T1-weighted post-gadolinium images. Two of the children also had T1-weighted post gadolinium spine images.
  
  
  RESULTS
  The MR brain findings consisted of cortical plaque and nodular hyperintense lesions on the noncontrast T1-weighted images in one child, marked, diffuse leptomeningeal enhancement in two children, and an enlarged, hypointense left temporal lobe with adjacent mild leptomeningeal enhancement in one child. The MR spine findings consisted of diffuse leptomeningeal enhancement in one child and hyperintensity of the cerebrospinal fluid in the other.
  
  
  CONCLUSIONS
  The T1-weighted pre- and post-contrast images were the best to demonstrate the MR findings in leptomeningeal melanosis which consisted of either diffuse or localized enhancement of the leptomeninges; or cortical plaque and nodular hyperintense lesions pre-contrast.
authors.affiliation: Department of Radiology, Children's Memorial Hospital, Chicago, Illinois 60614, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Byrd
authors.forename: M
authors.initials: M
authors.lastname: Reyes-Mugica
authors.forename: C F
authors.initials: CF
authors.lastname: Darling
authors.forename: P
authors.initials: P
authors.lastname: Chou
authors.forename: T
authors.initials: T
authors.lastname: Tomita
mesh_terms: D000293:Adolescent; D001099:Arachnoid / Q000473:pathology; D001706:Biopsy; D001921:Brain / Q000473:pathology; D001927:Brain Diseases / Q000175:diagnosis* / Q000473:pathology; D002648:Child; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008544:Melanocytes; D008548:Melanosis / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000473:pathology; D010841:Pia Mater / Q000473:pathology; D011379:Prognosis; D012189:Retrospective Studies; D012871:Skin Diseases / Q000175:diagnosis / Q000473:pathology