The Common Vein Copyright 2010
A pleomorphic xanthoastrocytoma is a low grade glioma seen in younger adults and children. It is thought to arise from subpial astrocytes of the cortex and generally occurs in the temporal lobes resulting in seizures. Although clinically it is a non aggressive tumor, it demonstrates mixed microscopic features. While there may be a high grade of atypia, suggestive of a higher grade lesion, there is generally no necrosis or mitotic activity. Other pathologic components include unusual lipidized neoplastic glial cells and chronic inflammatory cell infiltrates.
Clinically patients present with seizures.
Diagnosis can be suspected by the combination of clinical and imaging characteristics, however they are not specific. Ultimately the diagnosis is made by biopsy and pathologic evaluation.
While CT can be performed, MRI offers additional details in the evaluation of a pleomorphic xanthroastrocytoma. It appears as a large cortically based cystic lesion with an enhancing mural nodule, most often in the temporal lobe. It rarely demonstrates calcification which is best evaluated by CT. The solid component which enhances avidly generally abuts the meninges. These features are well seen on CT. Additional details more clearly seen on MR include a possible dural “tail” or enhancement of the adjacent meninges supporting this diagnosis. There is little surrounding increased T2 signal, or vasogenic edema, given the size of this lesion.
Treatment is generally surgical resection. Radiation and chemotherapy have not proven beneficial.