Specific Imaging Findings

Pleomorphic xanthoastrocytomas (PXAs) generally present as supratentorial hemispheric peripherally located cystic masses (60%) with a solid portion that abuts the meninges. The solid nodule enhances with contrast and may result in enhancement of a “dural tail” (70%) or scalloping of the adjacent inner table of the skull. They are most commonly found in the temporal, frontal, and parietal lobes but may occur anywhere in the cerebral hemispheres and even within the ventricles. Their size and degree of contrast enhancement are variable and calcifications and hemorrhage are rare. On MRI, the signal intensity of the solid tumor is variable but the cyst is nearly always of signal intensity similar to CSF on all sequences. Rarely, brain invasion, metastases, and/or necrosis are seen.

Pertinent Clinical Information

PXAs are tumors of young adults (with about 60% found below 18 years of age) without gender predilection. These are slow growing tumors which most commonly present with chronic seizures, headaches, and dizziness. Survival rates are better than 70% at 10 years after the initial diagnosis, however they may degenerate into higher grades. Surgery is the treatment of choice with gross total resection giving the best results, and re-resection is done for recurrences. Chemotherapy and radiation may be used for unresectable tumors as well as for primary and recurrent anaplastic PXAs, but their role is not clearly established. The only features that correlate with survival are the extent of initial resection and mitotic rate.