title: Occurrence and distribution of pilomyxoid astrocytoma.
abstract: OBJECTIVE
  To know the occurrence and distribution of Pilomyxoid Astrocytomas amongst tumours previously diagnosed histologically as Pilocytic Astrocytoma and to assess the clinical impact of this new entity.
  
  
  METHODS
  Retrospective Diagnostic review of all cases histologically diagnosed as WHO Grade I Astrocytoma at a single Neurosurgical unit between 1990 and 2003.
  
  
  RESULTS
  Of a total of 91 cases identified, 9 were found to have Pilomyxoid histology. Of these, 8 were children (mean age 3.33 years) and 1 adult. 6 tumours were hypothalamochiasmatic in location. The clinical course of Pilomyxoid tumours was aggressive marked by maturation, multiple recurrences and disease control was rarely achieved with single treatment modality as opposed to typical pilocytics. The overall survival of the pilomyxoid group was not statistically different from the pilocytic tumours.
  
  
  CONCLUSIONS
  Encompassing all age-groups and locations, Pilomyxoid Astrocytomas constitute about 10% of all tumours previously diagnosed as Pilocytic Astrocytoma. Nearly two-thirds are hypothalamo-chiasmatic in location. Knowledge of this entity is essential for appropriate aggressive treatment and follow-up.
authors.affiliation: Department of Neurosurgery, Leeds General Infirmary , Leeds , UK.
authors.forename: D
authors.initials: D
authors.lastname: Bhargava
authors.forename: P
authors.initials: P
authors.lastname: Sinha
authors.forename: P
authors.initials: P
authors.lastname: Chumas
authors.forename: Y
authors.initials: Y
authors.lastname: Al-Tamimi
authors.forename: A
authors.initials: A
authors.lastname: Shivane
authors.forename: A
authors.initials: A
authors.lastname: Chakrabarty
authors.forename: S
authors.initials: S
authors.lastname: Surash
authors.forename: F
authors.initials: F
authors.lastname: Novegno
authors.forename: D
authors.initials: D
authors.lastname: Crimmins
authors.forename: A K
authors.initials: AK
authors.lastname: Tyagi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000145:classification / Q000453:epidemiology / Q000401:mortality / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007029:Hypothalamic Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000473:pathology*; D015994:Incidence; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009093:Mucus; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D019574:Optic Nerve Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000473:pathology*; D012189:Retrospective Studies; D055815:Young Adult