title: MR imaging characteristics of pilomyxoid astrocytomas.
abstract: OBJECTIVE
  Pilomyxoid astrocytoma (PMA) is a recently described tumor that typically occurs in the chiasmatic-hypothalamic region in young children and has unique histopathologic and clinical characteristics. These tumors have been previously diagnosed as pilocytic astrocytoma (PA). PMA appears to have a higher rate of recurrence and CSF dissemination than typical PA.
  
  
  METHODS
  We analyzed MR findings in four patients with PMA and compared them with those of typical chiasmatic-hypothalamic PA.
  
  
  RESULTS
  MR findings of PMA were chiasmatic or hypothalamic enhancing solid tumor with hydrocephalus, highly homogeneous T2 signal intensity that extended into the deep white and gray matter, and CSF dissemination.
  
  
  CONCLUSIONS
  Larger series are needed before the MR imaging findings of chiasmatic or hypothalamic enhancing solid tumor with hydrocephalus, highly homogeneous T2 signal intensity extending into the deep white and gray matter, and CSF dissemination can be used in the differential diagnosis of such tumors.
authors.affiliation: Department of Radiology, Johns Hopkins University, Baltimore, MD 21287, USA.
authors.forename: Atilla
authors.initials: A
authors.lastname: Arslanoglu
authors.forename: Bayram
authors.initials: B
authors.lastname: Cirak
authors.forename: Alena
authors.initials: A
authors.lastname: Horska
authors.forename: James
authors.initials: J
authors.lastname: Okoh
authors.forename: Tarik
authors.initials: T
authors.lastname: Tihan
authors.forename: Leslie
authors.initials: L
authors.lastname: Aronson
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Avellino
authors.forename: Peter C
authors.initials: PC
authors.lastname: Burger
authors.forename: David M
authors.initials: DM
authors.lastname: Yousem
mesh_terms: D001254:Astrocytoma / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007029:Hypothalamic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D009897:Optic Chiasm / Q000473:pathology; D019574:Optic Nerve Neoplasms / Q000175:diagnosis* / Q000473:pathology; D013120:Spinal Cord Neoplasms / Q000556:secondary