title: Pleomorphic xanthoastrocytoma: report of two cases with unconventional clinical presentations.
abstract: OBJECTIVE
  Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytic neoplasm with a relative circumscribed architecture that typically arises superficially in the cerebral hemispheres of teenagers and young adults. Our aim is to highlight unconventional clinical presentations of this distinct neoplasm.
  
  
  METHODS
  We report two cases of PXA with unconventional clinical features, including clinical, pathologic, and immunohistochemical features.
  
  
  RESULTS
  The first case developed in the left frontal lobe of a 20-year-old female with neurofibromatosis type 1 (NF1). Focal anaplastic features were present. The neoplastic cells were immunoreactive for GFAP, S-100 protein and focally for synaptophysin, with a MIB-1/Ki-67 proliferative labelling index of 16%. The second case developed in a 39-year-old female as a suprasellar neoplasm. The neoplastic cells expressed GFAP, S-100 protein and focally CD34. The adenohypophysis was positive for synaptophysin and pituicytes for TTF1. Molecular studies were negative for BRAF (V600E) mutation in both cases.
  
  
  CONCLUSIONS
  PXA is a distinct circumscribed neoplasm that may present in unexpected locations or clinical backgrounds. Neuropathologists must be aware of these unconventional presentations in order to provide a precise diagnosis leading to appropriate treatment.
authors.forename: M Adelita
authors.initials: MA
authors.lastname: Vizcaíno
authors.forename: Dario V
authors.initials: DV
authors.lastname: Caccamo
authors.forename: Ellen
authors.initials: E
authors.lastname: Fox
authors.forename: Fausto J
authors.initials: FJ
authors.lastname: Rodriguez
mesh_terms: D000328:Adult; D001254:Astrocytoma / Q000175:diagnosis / Q000235:genetics / Q000473:pathology*; D001932:Brain Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000473:pathology*; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism*; D005909:Glioblastoma / Q000175:diagnosis / Q000235:genetics / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D009154:Mutation; D009418:S100 Proteins / Q000378:metabolism; D055815:Young Adult
chemical_list: D005904:Glial Fibrillary Acidic Protein; D009418:S100 Proteins