[Pleomorphic xanthoastrocytoma--a case report].

Pleomorphic xanthoastrocytoma (PXA) is a very rare and special kind of astrocytoma. Most of the patients have a relatively favorable prognosis despite its bizarre and pleomorphic cells. A 13 year old girl with PXA in the right occipitoparietal region is reported. Under light microscope, the tumor was markedly pleomorphic; mitosis was occasionally encountered and necrosis was absent. Immunohistochemically, cytoplasm of the tumor cells was positive for GFAP stain. Under electron microscope, many tumor cells contained glial filaments and large lipid vacuoles. Pericellular basal laminae could be found about some tumor cells, indicating a possible origin from subpial astrocyte. The clinicopathologic features, histogenesis, differential diagnosis and prognosis of PXA are discussed with review of literature.