Three patterns of clinical presentation exist: seizures, focal neurological deficits and/or symptoms of increased intracranial pressure (headache, nausea and vomiting). These patterns reflect the infiltrative nature of these tumors. Some tumor types such as ganglioglioma and dysembryoplastic neuroepithelial tumor almost always present with seizures.
The MRI appearance can vary. Pilocytic astrocytomas (WHO grade I) are usually well-circumscribed tumors that enhance markedly following gadolinium administration. The presence of enhancement with this tumor type does not correlate with aggressive behavior. Grade II astrocytomas are usually low intensity on T1-weighted images, and high intensity on T2-weighted images (Chapter 2, Fig. 25). There can be subtle mass effect. Higher-grade tumors can demonstrate varying degrees of enhancement. These tumors can be difficult to differentiate from other higher-grade tumors such as malignant ependymomas and PNETs that also occur in the cerebral hemispheres.
Was this article helpful?