title: Immunophenotype of pleomorphic xanthoastrocytoma.
abstract: Pleomorphic xanthoastrocytoma (PXA) is an uncommon tumor, often seizure-associated and occurring in the temporal lobe of young adults. Although its cells are considered astrocytic in nature, recent studies suggest the presence of neuronal differentiation and a possible relationship to glioneuronal neoplasms. We immunostained 40 cases of PXA, including two composite PXA-gangliogliomas (PXA-GG), with a panel of glial (glial fibrillary acidic protein, S-100 protein) and neuronal markers (class III beta-tubulin, synaptophysin, neurofilament proteins, MAP2, and chromogranin A). Conventional PXAs demonstrated immunoreactivity for glial fibrillary acidic protein (100% of cases), S-100 protein (100%), class III beta-tubulin (73%), synaptophysin (38%), NF proteins (18 and 8%), and MAP2 (8%). Chromogranin A stain was absent in all conventional PXA cases. Neoplastic ganglion cells in both PXA-GGs stained with class III beta-tubulin, synaptophysin, and chromogranin A. Ultrastructural studies, performed in nine cases, demonstrated neuronal features including microtubules, dense core granules, and/or clear vesicles largely limited to cell processes (two PXAs) and in the cytoplasm (PXA component of one PXA-GG). Although the essential nature of PXA is clearly and uniformly glial, the significance of the limited neuronal differentiation is unclear, as it is the relationship between conventional PXA and PXA-GG. We found no evidence that the former is a precursor of the latter.
authors.affiliation: Department of Pathology, Mayo Clinic, Rochester, Minnesota 55905, USA. Giannini.Caterina@Mayo.edu
authors.forename: Caterina
authors.initials: C
authors.lastname: Giannini
authors.forename: Bernd W
authors.initials: BW
authors.lastname: Scheithauer
authors.forename: Maria B S
authors.initials: MB
authors.lastname: Lopes
authors.forename: Takanori
authors.initials: T
authors.lastname: Hirose
authors.forename: Johan M
authors.initials: JM
authors.lastname: Kros
authors.forename: Scott R
authors.initials: SR
authors.lastname: VandenBerg
mesh_terms: D001254:Astrocytoma / Q000737:chemistry* / Q000276:immunology; D015415:Biomarkers / Q000032:analysis; D001932:Brain Neoplasms / Q000737:chemistry* / Q000276:immunology; D053379:Chromogranin A; D002864:Chromogranins / Q000032:analysis; D000939:Epitopes / Q000032:analysis*; D018303:Ganglioglioma / Q000737:chemistry; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D008565:Membrane Proteins / Q000032:analysis; D008869:Microtubule-Associated Proteins; D016900:Neurofilament Proteins / Q000032:analysis; D009457:Neuroglia / Q000276:immunology*; D009474:Neurons / Q000276:immunology*; D009418:S100 Proteins / Q000032:analysis; D016708:Synaptophysin / Q000032:analysis; D014404:Tubulin / Q000032:analysis
chemical_list: D015415:Biomarkers; D053379:Chromogranin A; D002864:Chromogranins; D000939:Epitopes; D005904:Glial Fibrillary Acidic Protein; C489788:MAP2 protein, human; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D016900:Neurofilament Proteins; D009418:S100 Proteins; C110294:S100A1 protein; D016708:Synaptophysin; D014404:Tubulin