title: Combined oligodendroglioma/pleomorphic xanthoastrocytoma: a probable collision tumor: case report.
abstract: OBJECTIVE
  We report the first case of combined oligodendroglioma and pleomorphic xanthoastrocytoma.
  
  
  METHODS
  A female college student and competitive cross-country runner presented to the Mayo Clinic at age 18 years with complaints of progressive headache and visual disturbances. Neuroimaging revealed a heavily calcified left parieto-occipital mass with focal enhancement and remodeling of the overlying calvarium.
  
  
  METHODS
  A histological examination of the nearly gross total resection specimen disclosed a low-grade oligodendroglioma discretely abutting a superficially situated focus of pleomorphic xanthoastrocytoma. Ten months thereafter, a recurrence was suspected on the basis of the detection of a new focus of nodular enhancement. This lesion stabilized after radiation therapy, and the patient is well, without apparent residual disease 2.8 years after surgery.
  
  
  CONCLUSIONS
  This unique neoplasm is presumed to represent a collision tumor, its biological behavior being similar to that of oligodendroglioma alone. However, the possibility of an unusual, mixed oligoastrocytoma with pleomorphic xanthoastrocytoma as the astrocytic component cannot be excluded entirely. Potentially, both components have the capacity for recurrence and anaplastic transformation.
authors.affiliation: Division of Neuropathology, Washington University School of Medicine, St. Louis, Missouri 63110-1093, USA. aperry@pathology.wustl.edu
authors.forename: A
authors.initials: A
authors.lastname: Perry
authors.forename: B W
authors.initials: BW
authors.lastname: Scheithauer
authors.forename: D M
authors.initials: DM
authors.lastname: Szczesniak
authors.forename: J L
authors.initials: JL
authors.lastname: Atkinson
authors.forename: J T
authors.initials: JT
authors.lastname: Wald
authors.forename: J E
authors.initials: JE
authors.lastname: Hammak
mesh_terms: D000293:Adolescent; D001254:Astrocytoma / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D001932:Brain Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy; D009778:Occipital Lobe; D009837:Oligodendroglioma / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D010296:Parietal Lobe