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Pleomorphic Xanthoastrocytoma

Last Updated: November 15, 2020

Figure 1: (Top Left and Top Right) This pleomorphic xanthoastrocytoma (PXA) demonstrates avid enhancement on postcontrast T1-weighted imaging. The nonenhancing cystic components are also evident. The adjacent enhancing dural thickening (dural tail) is also a variable feature of PXAs. (Bottom) Edema is also variable and can be present, as shown in this axial T2-weighted image.

Figure 1: (Top Left and Top Right) This pleomorphic xanthoastrocytoma (PXA) demonstrates avid enhancement on postcontrast T1-weighted imaging. The nonenhancing cystic components are also evident. The adjacent enhancing dural thickening (dural tail) is also a variable feature of PXAs. (Bottom) Edema is also variable and can be present, as shown in this axial T2-weighted image.

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

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

BASIC DESCRIPTION

  • Supratentorial cortical/peripheral astrocytic tumor

PATHOLOGY

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

CLINICAL FEATURES

  • Typically afflicts children and young adults (10–36 years of age; 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 are important prognostic factors
    • Younger patient age and BRAF mutations are associated with better prognosis

IMAGING FEATURES

  • General
    • Hemispheric tumor often located peripherally with cortical ± leptomeningeal involvement
    • Temporal lobe > frontoparietal > occipital
    • Classically cystic with solid mural nodule; nodule often abuts pial surface
    • Can have enhancing dural tail of leptomeningeal attachment
    • Often with infiltration of adjacent parenchyma beyond margin of visible tumor
    • ±Adjacent cortical dysplasia
  • CT Imaging
    • Hypodense cystic component; isodense to hyperdense mural nodule or solid components
    • Minimal-to-moderate adjacent edema
    • Calcification and hemorrhage uncommon
    • Strong enhancement of mural nodule/solid components on contrast-enhanced CT imaging
  • MRI
    • T1WI: solid component isointense to hypointense to gray matter; cystic component isointense to cerebrospinal fluid (CSF)
    • T2WI: solid component isointense to hypointense to gray matter; cystic component isointense to CSF; minimal-to-moderate surrounding T2-hyperintense vasogenic edema
    • FLAIR: heterogeneous signal intensity
    • DWI: solid components can show diffusion restriction
    • T1WI+C: generally strong enhancement; sometimes enhancing dural tail/leptomeninges

IMAGING RECOMMENDATIONS

  • MRI with contrast, including coronal images for temporal lobe evaluation

For more information, please see the corresponding chapter in Radiopaedia.

Contributor: Rachel Seltman, MD

DOI: https://doi.org/10.18791/nsatlas.v1.03.01.35

References

Crespo-Rodríguez AM, Smirniotopoulos JG, Rushing EJ. MR and CT imaging of 24 pleomorphic xanthoastrocytomas (PXA) and a review of the literature. Neuroradiology 2007;49:307–315.

Ida CM, Rodriguez FJ, Burger PC, et al. Pleomorphic xanthoastrocytoma: natural history and long-term follow-up. Brain Pathol 2015;25:575–586.

Louis DN, Ohgaki H, Wiestler OD, et al. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol 2007;114:547.

Moore W, et al. Pleomorphic xanthoastrocytoma of childhood: MR imaging and diffusion MR imaging features. AJNR Am J Neuroradiol 2014;35:2192–2196.

Osborn AG, Salzman KL, Jhaveri MD. Diagnostic Imaging (3rd ed). Philadelphia, PA: Elsevier; 2016.

Yu S, He L, Zhuang X, et al. Pleomorphic xanthoastrocytoma: MR imaging findings in 19 patients. Acta Radiol 2011;52:223–228.

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