Pleomorphic xanthoastrocytoma, a distinctive astroglial tumor: neuroradiologic and pathologic features.

Overview

PURPOSE: To analyze and discuss CT and MR features of pleomorphic xanthoastrocytoma (PXA) and present salient histopathologic features of this distinctive astroglial tumor. METHOD: CT, MR, and histopathologic studies on seven patients with the histologic diagnosis of PXA were reviewed retrospectively. RESULTS: All patients were in their first 3 decades of life when first diagnosed and demonstrated peripherally situated supratentorial tumors of varying size involving the superficial cortex and leptomeninges. Five of six cases examined with CT showed areas of mixed attenuation with four demonstrating well-demarcated enhancement. MR demonstrated low or mixed signal intensity on T1-weighted and high or mixed signal intensity on T2-weighted sequences. All five who received gadopentetate dimeglumine showed well-defined enhancement. Three showed cyst formation. Typical histologic features included marked cellular pleomorphism with giant cells, bizarre nuclei, variable cytoplasmic lipidization and positive immunoreactivity for glial fibrillary acidic protein. Necrosis and endothelial-pericytic cell proliferation were absent. CONCLUSION: PXA has a highly suggestive neuroradiologic and distinctive histopathologic appearance.