Pleomorphic Xanthoastrocytoma (PXA)

Figure 1: This PXA demonstrates avid enhancement on postcontrast T1WI (top row). The nonenhancing cystic components are also evident. The adjacent enhancing dural thickening (dural tail) is also a variable feature of PXA. Edema is also variable and may be present, as on this axial T2WI (bottom).

 

Figure 2: T1 pre- (top row left) and post-contrast (top row right – axial, bottom row left - coronal) images show a brightly enhancing superficial lesion in the left parietal lobe. Although sometimes present, no duraltail is visible in this example of PXA. A cyst or CSF cleft around the mass is clearly visible on coronal T2-weighted image (bottom row right). The large amount of surrounding hyperintense edema is also more clearly visible on T2.

Basic Description

  • Supratentorial cortical/peripheral astrocytic tumor

Pathology

  • WHO II
  • Astrocyte pleomorphism and lipid-containing cells
  • May show anaplastic features (10-15%)
  • Malignant transformation in minority of cases

Clinical Features

  • Typically afflicts children and young adults (10-36 years; mean 26 years)
  • No gender predilection
  • Commonly presents with seizures, often of temporal lobe origin
  • Overall good prognosis
    • 10-year survival 70%
    • Extent of tumor resection and mitotic index important prognostic factors
    • Younger patient age and BRAF mutations associated with better prognosis

Imaging Features

  • General
    • Hemispheric tumor often located peripherally with cortical ± leptomeningeal involvement
    • Tem...
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