In 1979, researchers described a series of young patients with clinically and histologically distinctive supratentorial gliomas which were designated pleomorphic (meningocerebral) xanthoastrocytomas (PXA). Significantly, patients with these neoplasms were reported to have a relatively favorable prognosis. The authors present a new case of PXA in a 32-year-old man. This case is unique for two reasons: (1) a relatively rapid fatal outcome with death 21 months after diagnosis; and (2) the presence, at autopsy, of extensive recurrent tumor with features of a malignant astrocytoma. Detailed electron microscopic and immunohistochemical studies, supporting the proposed subpial astrocytic origin of PXA, are presented. Literature pertaining to PXA is reviewed. This report illustrates the unique features of PXA and demonstrates its potential for aggressive behavior.