Composite pleomorphic xanthoastrocytoma-epithelioid glioneuronal tumor with BRAF V600E mutation - report of three cases

Clin Neuropathol. 2014 Mar-Apr;33(2):112-21. doi: 10.5414/NP300679.

Abstract

We report three examples of a composite pleomorphic xanthoastrocytoma-epithelioid glioneuronal tumor (PXAEGT) occurring in an adolescent male and two young women. All were superficial and two were located in proximity to the optic nerves. Previously reported composite PXA-gangliogliomas (PXA-GG), have been considered "collision tumors" since little intermingling of the two elements has been present. In contrast, we hypothesized that the two elements of the PXA-EGT might instead derive from a common origin. To test this, we sampled the separate regions of these biphasic tumors and assessed each component for the BRAF V600E mutation, a genetic feature seen in two-thirds of pure PXAs. The BRAF mutation was found in both tumor areas in all cases, suggesting a common origin for the components, rather than a collision tumor. These biphasic PXA-EGT cases represent a new histomorphological combination of neuroepithelial neoplastic elements. These cases further expand the range of glial neoplasia in which epithelioid morphology is encountered, and add to the growing list of biphasic tumors harboring the BRAF V600E mutation.

MeSH terms

  • Adolescent
  • Astrocytoma / genetics*
  • Astrocytoma / pathology*
  • Astrocytoma / surgery
  • Brain Neoplasms / genetics*
  • Brain Neoplasms / pathology*
  • Brain Neoplasms / surgery
  • DNA / genetics
  • Epithelioid Cells / pathology
  • Female
  • Ganglioglioma / genetics*
  • Ganglioglioma / pathology*
  • Ganglioglioma / surgery
  • Headache / etiology
  • Humans
  • Immunohistochemistry
  • Intracranial Hemorrhages / complications
  • Intracranial Hemorrhages / pathology
  • Magnetic Resonance Imaging
  • Male
  • Mental Disorders / etiology
  • Microscopy, Electron
  • Mutation / genetics*
  • Paresis / etiology
  • Polymerase Chain Reaction
  • Proto-Oncogene Proteins B-raf / genetics*
  • S100 Proteins / metabolism
  • Speech Disorders / etiology
  • Young Adult

Substances

  • S100 Proteins
  • DNA
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf