PLEOMORPHIC XANTHOASTROCYTOMA, A DISTINCTIVE ASTROGLIAL TUMOR - NEURORADIOLOGIC AND PATHOLOGICAL FEATURES

PURPOSE: To analyze and discuss CT and MR features of pleomorphic xant hoastrocytoma (PXA) and present salient histopathologic features of th is distinctive astroglial tumor. METHOD: CT, MR, and histopathologic s tudies on seven patients with the histologic diagnosis of PXA were rev iewed retrospectively. RESULTS: All patients were in their first 3 dec ades of life when first diagnosed and demonstrated peripherally situat ed supratentorial tumors of varying size involving the superficial cor tex and leptomeninges. Five of six cases examined with CT showed areas of mixed attenuation with four demonstrating well-demarcated enhancem ent. 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. Th ree showed cyst formation. Typical histologic features included marked cellular pleomorphism with giant cells, bizarre nuclei, variable cyto plasmic lipidization and positive immunoreactivity for glial fibrillar y acidic protein. Necrosis and endothelial-pericytic cell proliferatio n were absent. CONCLUSION: PXA has a highly suggestive neuroradiologic and distinctive histopathologic appearance.