CT and MRI of pleomorphic xanthoastrocytoma: unusual biologic behavior

Our goal was to present three cases of pleomorphic xanthoastrocytoma (PXA) with unusual radiographic, clinical, and pathologic aspects.

The imaging findings in three patients with proven PXA were reviewed and correlated with clinical information and review of pathologic material. Two females and one male were studied, ranging in age from 8 to 42 years old. All patients underwent MRI with gadolinium (0.1 mmol/kg). Two of the patients had serial MR studies. CT scans with and without contrast agent were also available for two patients. The medical records for all three patients were reviewed. Radiographic findings were correlated with pathologic material obtained at surgery.

Seizure disorder was the initial presentation in two patients. The third patient presented with a lytic lesion of the calvarium. Radiographic features showed rapid progression of disease over 3 months in one patient. Rapid tumor recurrence (within 7 months) without malignant transformation was proven in another patient. While typical pathological features of PXA were evident in two cases, a mixed tumor consisting of PXA and other tissue components was identified in the third case.

Although generally regarded as a benign lesion in the literature, PXA has potential for aggressive behavior. Rapid tumor recurrence can occur without malignant transformation. Radiographic features may evolve over a short period of time. Dura and bony calvarium are not necessarily respected. PXA can occur as a separate entity or as a tumor of mixed components.